TABLE OF CONTENTS

Acknowledgement i

Abstract ii

1. OVERVIEW

1.1 About Simplex Infrastructures Ltd. 1

1.2 About Silveroak Estate 4

1.2.1 Master Plan 6

1.2.2 Proposed Logistics 7

1.2.3 Floor Plan of Towers 8

2. RESIDENTIAL BUILDING CONSTRUCTION

2.1 Introduction 10

2.2 Safety Practices 12

2.2.1 Fire Safety 14

2.2.2 Electrical Safety 16

2.2.3 Organization Chart 18

2.2.4 Personal Protective Equipment (PPE) 19

2.3 Construction Equipments 21

2.4 Construction Materials 25

2.5 Planning 35

2.6 Surveying 37

2.7 Quality Control 41

2.8 Reinforcement 51

2.9 Brickwork, Plastering and Finishing 53

2.10 Foundation: Pile Work 58

2.11 Shuttering and Scaffolding 61

2.12 General Notes 65

2.13 Store Management 69

2.14 Conclusion 72

References 73

i

ACKNOWLEDGEMENT:

The success and the final outcome of this training required a lot of guidance and assistance

from a lot of people and I am extremely fortunate to get this all along the due course of my

training. First of all I feel greatly indebted to Mr. S.K. Maity (Technical Director, Simplex

Infrastructures Ltd.) and Mr. Susanta Bhattacharjee (Project Manager, Silveroak Estate

Project), who provided us the golden opportunity to undergo training in this valuable project

of Simplex Infrastructures Ltd. A special thanks to Mr. Subhajeet Ganguly, for his constant

support, cooperation, and motivation provided to me during the training.

I am also deeply grateful to Mr. Debanjan Basu, Mr. Puspajit Sarkar, Mr. Milan Kumar Basu,

Mr. Janardan Mundhra, Mr. Pradip Maity, Mr. Pratap Kumar Das, and Mr. Pinaki

Choudhury, to name a few, from Simplex Infrastructures Ltd. for the supervision and support

provided by them during the training.

I would like to thank all my fellow trainees, without whose company this project would never

have ended in a fruitful way.

Finally, I would like to thank the entire team of both Simplex Infrastructures Ltd. and

Salarpuria Group related to the Silveroak Estate project for making this project a success.

ii

ABSTRACT

This report is an account of a month long industrial training received at Simplex

Infrastructures Ltd.’s residential project in collaboration with Salarpuria group, the Silveroak

Estate at Rajarhat. During the course of the training, a lot of exposure was received on the

practical works done in the construction site. The various departments of the site, which

worked together as one unit, which included the departments of Safety, Planning, Surveying,

Construction, Quality Control, Mechanical, Electrical and Store, was visited and thorough

knowledge was received about the method of functioning of these units and the technical

details. All the insights received during the industrial training are hereby accounted in the

report.

1. OVERVIEW

1

1.1 ABOUT SIMPLEX INFRASTRUCTURES LTD.

Simplex Infrastructures Limited, an ISO 9001:2008 certified company is one of the largest

infrastructure solution providers in India since 1924. As the first name in ground engineering,

Simplex has played a part in the construction of many historical buildings and structures of India.

The company was incorporated on 19th December 1924 under the control of H.P. Lancaster of the

United Kingdom, and later the company was taken over by the Kolkata-based Mundra family after

the Indian independence. SIL provides the services in the areas of Ground Engineering, Power,

Industrial, Urban Utilities, Building & Houses, Roads, Railways, Bridges and Marine. The Company

has diversified geographical presence across India and overseas also. The year of inception itself,

SIL had introduced cast-in-situ driven piles in Asia, at Kolkata. Then, the company had started

construction of major Steel Plants during the year 1935 and had built King George Docs, Mumbai in

1940. SIL had entered into the civil & structural construction of Industrial Projects during the year

1952 and further forayed into Housing and Building segment in the period of 1955. In 1958, the

company was designed and constructed the first ever RCC framed structure in Asia; the 17- storied

National Tower at Kolkata. During the year 1960, SIL made a foray into the civil & structural

construction of Thermal Power Plants and has been associated with over 80% of Thermal Power

Plants across India ranging from 10 MW to 1000 MW Turbo Generators. Urban Utilities segment

was added to the company's activities in the year 1965, by the way of water treatment plant at

Howrah for HIT. After three years, in 1968, took up the Marine Construction and now associated

with all the major ports in India. The overseas presence was made by the company in the year 1982

itself, opened the first overseas office for the execution of projects in Sri Lanka and also in the same

year of 1982, SIL made its foray into Roads, Bridges and Railways segment. Started piling jobs in

UAE, Abu Dhabi in the year 1990 and in 1991 SIL developed indigenous technique for jointed pre-

cast concrete piles upto 150 meters depth at Ernakulam. The Company successfully built an

international class hotel at Tashkent, Uzbekistan during the year 1992 and SIL went to public in the

year of 1993. During the year 1998, the company entered into an innovative LIG/MIG sourcing on

turnkey basis. Also SIL made its foray into turnkey coding towards construction in the identical

period of 1998. The Company had started the event of civil & structural construction of Nuclear

Power Plants since the year 2002. During 2003, SIL undertakes the civil & structural construction of

Hydro Power Plants and also established presence in the Middle East Countries. An ISO 9001:2000

2

certification was handed over to the company in 2004 and in 2005, the company had changed its

name from Simplex Concrete Piles (India) Limited to Simplex Infrastructures Limited for a more

holistic representation of the company. In the same year, SIL secured contract for an irrigation canal

in Hyderabad. During the year 2006, the company secured contract for doubling of railway tracks on

South-Central Railway line in Guntakal - Raichur railway, AP. Also obtained several piling and civil

contracts in Middle East Countries. In 2007, the company bagged Rs 4.52 billion order in industrial

structures segment, Rs 1.78 billion in urban utilities, Rs 1.12 billion in piling and Rs 600 million in

marine structures segment. Also, SIL secured a contract from DP World for Rs 5,800 million for

ICTT Kochi Phase 1A in November 2007. The Rig and Real Estate Development business was

added to the company's business in the year 2008. SIL bagged new orders worth Rs 6.53 billion from

different sectors including an order from Ritz Carlton Hotel, Bangalore, for the construction of a

cement plant, sewerage system and thermal power plant in March 2008.

• Ranked among Top 5 India's Fastest Growing Large Companies by Business Today, June 15, 2008.

• Titled as "Overall Best Managed Company" by Asia Money in 2005.

• Twice nominated as "Most Admired Infrastructure Company" by NDTV Profit in 2006 & 2008.

• Over 7700 employees as on March 31, 2010 with more than 80% being technically qualified.

• The company enjoys an uninterrupted profit track record since inception.

• The Company reported a turnover of Rs. 45524 million and profit after tax of Rs. 1225 million for

the year 2009 - 2010.

• The Company's shares are listed on the National Stock Exchange, Bombay Stock Exchange and

Calcutta Stock Exchange enjoying a market capitalization of Rs. 25000 million (as on 31st July

2010).

3

CORPORATE POLICIES

H.S.E. POLICY QUALITY POLICY

ISO 9001:2008

4

1.2 ABOUT SILVEROAK

ESTATE

The Silveroak Estate Project is a residential project and is a joint venture of the two construction giants Simplex Infrastructures Ltd. and Salarpuria Group. The project is located in the heart of the upscale and much coveted Rajarhat area of Kolkata, and is in proximity to hospitals, educational institutes, shopping malls (City Centre II - 2 km), Kolkata Airport (2.4 km), Rajarhat Central Business District and Salt Lake Sector V. This project, which is of nearly 440 crores, is rated as a Five Star by CRISIL Real Estate Star Ratings. Construction on the site started on December 2011, and is expected to reach completion by June 2016.

OVERVIEW

Land Area : 7.5 Acres (Approx.) in Ph. I

No. of Blocks : 8 in Phase I

No. of Floors : B+G+8

No. of Flats: 516 (approx.) in Phase I

Unit Size

2 BHK Flat ( sqft. ) : 1,080 to 1,280

3 BHK Flat ( sqft. ) : 1,512 to 1,660

4 BHK Flat ( sqft. ) : 2,003

5 BHK Duplex ( sqft. ) : 3,320

SBP: 22%

Open Space: 70%

Ceiling Height: 9.6 Feet

Municipality: Rajarhat Gopalpur

Municipality

Water Supply: Boring

Electricity: WBSEB

FEATURES

Club (Approx 30, 000 Sq. Ft. ) Cafeteria with al fresco dining

Mini Theatre Banquet Hall

Jogging track Reading room

Community hall Bar B-Q Corner

Multi Gymnasium Indoor games room

Senior citizens park Outdoor Playing area

Steam Room & Jacuzzi Children’s park & play area

Card Room Swimming Pool with Baby pool

3 tier security system 24 Hr Power Back up (Limited)

Water filtration plant Landscape garden

Laundry facilities Utility store, etc

5

SPECIFICATIONS

Foundation :

R.C.C. Pile Foundation.

Structure :

RCC framed Structure including Basement.

Flooring :

Vitrified Tiles of Reputed make, Wooden flooring in master

bedroom.

. Exterior Finish :

Latest available durable outer finish.

Other Doors :

All doors are of wooden frame with solid core flush Doors.

Windows :

UPVC/Powdered coated Aluminum window open able type.

Kitchen :

Granite cooking platform with 600 mm high Ceramic tile

Dado. Flooring of anti-skid tiles.

Extra Facility :

Common Toilet for servant in each floor, Power back up at

an extra cost.

Electrical :

Insulated copper concealed wiring with Modular switches.

MCB for each flat, TV/AC point in all Bed rooms and

Living Dining, AC ledge will be provided.

Main Doors :

Main doors will be of wooden frame and Teak wood polish

finish. Night latch, decorative handle, magic eye will be

provided of reputed make

Toilet :

Hot & Cold Water line by CPVC pipes. C.P. flooring will be of First class and reputed make. Decorative Ceramic tiles up-to

2.4 M. Floor is of matching antiskid Ceramic tiles.

INFORMATION

CLIENT: Salarpuria Group

CONTRACTOR: Simplex Infrastructures Ltd.

SPONSOR: Salarpuria Simplex Dwellings LLP

PRINCIPLE DESIGNERS: Aedos

ARCHITECT: Sanon Sen & Associates Pvt. Ltd.

STRUCTURAL CONSULTANT: S.P.A. Consultants Pvt. Ltd.

MEP CONSULTANTS: Spectral Services Consultants Pvt. Ltd.

LEGAL ADVISOR: Victor Moses & Co.

SITE CODE: C2668

1.2.1

1.2.2

8

1.2.3 FLOOR PLAN OF TOWERS:

Figure 1: Floor Plan of Towers 1 & 2

9

Figure 2: Floor Plan of Towers 3 & 4

2. RESIDENTIAL BUILDING

CONSTRUCTION

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2.1 INTRODUCTION:

Building construction is the process of preparing for and forming buildings and building

systems. Construction starts with planning, design, and financing and continues until the

structure is ready for occupancy. Building construction is the process of adding structure

to real property or construction of buildings. However, all building construction projects

include some elements in common – design, financial, estimating and legal considerations.

Normally, the job is managed by a project manager, and supervised by a construction

manager, design engineer, construction engineer or project architect. The engineer has to

keep in mind the municipal conditions, building bye laws, environment, financial capacity,

water supply, sewage arrangement, provision of future, aeration, ventilation etc., in

suggestion a particular type of plan to any client. Many projects of varying sizes reach

undesirable end results, such as structural collapse, cost overruns, and/or litigation. For this

reason, those with experience in the field make detailed plans and maintain careful oversight

during the project to ensure a positive outcome.

The different departments involved in building construction are:

• Planning

• Survey

• Estimation

• Resources

• Quality

• Safety

• Execution

Sequence of work in building construction:

1) Site Clearance 2) Demarcation of Site

3) Positioning of Central coordinate ie (0,0,0) as

per grid plan

4) Surveying and layout

5) Excavation 6) Laying of PCC

7) Bar Binding and placement of foundation steel 8) Shuttering and Scaffolding

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9) Concreting 10) Electrical and Plumbing

11) Deshuttering 12) Brickwork

13) Doors and windows frames along with lintels 14) Wiring for electrical purposes

15) Plastering 16) Flooring and tiling work

17) Painting 18) Final Completion and handing over the

project

For the successful execution of a project, effective planning is essential. Those involved with

the design and execution of the infrastructure in question must consider the environmental

impact of the job, the successful scheduling, budgeting, construction site safety, availability

and transportation of building materials, logistics, inconvenience to the public caused

by construction delays and bidding, etc.

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2.2 SAFETY PRACTICES

Safety practices are adopted at workplace to protect human life and property of the company in a safe and secure manner. Workplace safety is about preventing injury and illness to employees and volunteers in the workplace. Therefore, it's about protecting the company's most valuable asset: its workers. By protecting the employees’ well-being, the company reduces the amount of money paid out in health insurance benefits, workers' compensation benefits and the cost of wages for temporary help. Also factor in saving the cost of lost-work hours (days away from work or restricted hours or job transfer), time spent in orienting temporary help, and the programs and services that may suffer due to fewer service providers, stress on those providers who are picking up the absent workers' share or, worse case, having to suspend or shut down a program due to lack or providers.

SAFETY AT CONSTRUCTION SITE

The leading safety hazards on site are falls from height, motor vehicle crashes, excavation accidents, electrocution, machines, and being struck by falling objects. Some of the main health hazards on site are asbestos, solvents, noise, and manual handling activities.

Falls from heights are the leading cause of injury in the construction industry. Fall protection is needed in areas and activities that include, but are not limited to: ramps, runways, and other walkways; excavations; hoist areas; holes; formwork; leading edge work; unprotected sides and edges; overhand bricklaying and related work; roofing; precast erection; wall openings; residential construction; and other walking/working surfaces. The height limit where fall protection is required is not defined. It used to be 2 metres in the previous issue of Work at Height Regulations. It is any height that may result in injury from a fall. Protection is also required when the employee is at risk to falling onto dangerous equipment. Fall protection can be provided by guardrail systems, safety net systems, personal fall arrest systems, positioning device systems, and warning line systems. All employees should be trained to understand the proper way to use these systems and to identify hazards. The employee or employer will be responsible for providing fall protection systems and to ensure the use of these systems. Employees on construction sites also need to be aware of dangers on the ground. The hazards of cables running across roadways were often seen, until cable ramp equipment was invented to protect hoses and other equipment which had to be laid out.

The safety guidelines as briefed by the Safety Department personals should be followed thoroughly. Toolbox meetings should be conducted and the safety details as laid down by the Safety personals should be followed by the Engineer or Supervisor, Lack of safety causes accidents, which further causes:

• Loss of life at work • Loss of company as compensation has to be paid to the injured party • Damage to property • Damages the reputation of the company

• Causes panic within the workers

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OCCUPATIONAL HEALTH, SAFETY AND ENVIRONMENT POLICY AT

SIMPLEX INFRASTRUCTURES LTD.

SAFETY INSTRUCTIONS AT SILVEROAK ESTATE, SALUA, RAJARHAT (SITE C-2668)

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2.2.1 FIRE SAFETY Each year there are hundreds of fires on construction sites, potentially putting the lives of workers and members of the public at risk. Fire safety in construction is about preventing fires from starting and ensuring people's safety if they do. The various steps to be taken for ensuring safety against fire at the site are:

• Risk assessment:

1. Identify hazards: Consider how a fire could start and what could burn;

2. People at risk: Employees, contractors, visitors and anyone who is vulnerable, e.g. disabled;

3. Evaluation and action: Consider the hazards and people identified in 1 and 2 and act to remove

and reduce risk to protect people and premises;

4. Record, plan and train: Keep a record of the risks and action taken. Make a clear plan for fire

safety and ensure that people understand what they need to do in the event of a fire; and

5. Review: Your assessment regularly and check it takes account of any changes on site.

• Means of escape:

1. Routes: Your risk assessment should determine the escape routes required, which must be kept

available and unobstructed;

2. Alternatives: Well-separated alternative ways to ground level should be provided where possible;

3. Protection: routes can be protected by installing permanent fire separation and fire doors as soon as

possible;

4. Assembly: Make sure escape routes give access to a safe place where people can assemble and be

accounted for. On a small site the pavement outside may be adequate; and

5. Signs: Will be needed if people are not familiar with the escape routes. Lighting should be

provided for enclosed escape routes and emergency lighting may be required.

• Means of giving warning: Set up a system to alert people on site. This may be temporary or permanent mains operated fire alarm (tested regularly), a klaxon, an air horn or a whistle, depending on the size and complexity of the site. The warning needs to be distinctive, audible above other noise and recognizable by everyone. • Means of fighting fire: Fire extinguishers should be located at identified fire points around the site. The extinguishers should be appropriate to the nature of the potential fire.

15

FIRE TRIANGLE:

CLASSIFICATION OF FIRE AND TYPE OF EXTINGUISHER USED:

Type: Description: Fuel examples: Extinguished by: Class A Combustible

Materials Wood, Paper Water, Foam

Class B/C Flammable Liquid, Gases

Petrol, Propane Foam, CO2

Class C or E Electrical Appliances Computers, Fuse boxes

Dry Chemical Powder, CO2

Class D Combustible Metals

Magnesium, Lithium Dry Chemical Powder

Class K or F Combustible Cooking Media

Cooking oils and fats Watermist

HOW TO USE A FIRE EXTINGUISHER?

By following the PASS rule:

• P : Pull the pin • A : Aim at the base of fire

• S : Squeeze the handle • S : Sweep side-to-side

HOW TO RESPOND IN CASE OF A FIRE?

By following the RACE rule:

• R : Rescue the victims

• A : Alert the nearest fire station and necessary persons by calling the helpline • C : Contain the spread of fire

• E : Extinguish fire by following the P.A.S.S. rule and Evacuate

Fire Triangle

The fire triangle or combustion triangle is a simple model for understanding the necessary ingredients for most fires. The triangle illustrates the three elements a fire needs to ignite: heat, fuel, and an oxidizing agent (usually oxygen). A fire naturally occurs when the elements are present and combined in the right mixture, and a fire can be prevented or extinguished by removing any one of the elements in the fire triangle. For example, covering a fire with a fire blanket removes the "oxygen" part of the triangle and can extinguish a fire.

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2.2.2 ELECTRICAL SAFETY

In worksites alone, electricity can be indispensable. It is used to drill holes, transport devices, weld metals, process food and heat chemicals. But with its efficiency comes great danger. Many times electrical hazards have become the cause of injuries and fatalities in the workplace. It’s actually one of the leading causes of accidents in construction sites. Like other serious hazards, electrical shock is not inevitable. What sets it apart, though, from other workplace perils is that it is often the beginning of a series of accidents. Its final injury may be a burn, cut, broken bone or a fall. The most common among these is burn and it may come in the form of electrical burns, arc burns, and thermal contact burns. The first step towards electrical safety is controlling or eliminating factors in your workplace that pose electrical hazards. Ground fault electrical shock happens to be the most common electrical hazard in construction sites. At the construction site of Silveroak Estate, the following electrical safety equipments are used:

• Miniature Circuit Breakers (MCBs): It is an automatically operated electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit. Its basic function is to detect a fault condition and interrupt current flow. A circuit breaker can be reset (either manually or automatically) to resume normal operation.

• Earth Leakage Circuit Breakers (ELCBs): It is a safety device used in electrical installations with high earth impedance to prevent shock. It detects small stray voltages on the metal enclosures of electrical equipment, and interrupts the circuit if a dangerous voltage is detected.

• Residential Current Breaking Overload (RCBO): It is installed at a place where there is a need to prevent overload on a particular circuit at the same time as preventing anyone getting a shock that has the potential to kill them.

• Residual Current Circuit Breakers (RCCBs): It is an electrical wiring device that disconnects a circuit whenever it detects that the electric current is not balanced between the energized conductor and the return neutral conductor. Such an imbalance may indicate current leakage through the body of a person who is grounded and accidentally touching the energized part of the circuit, causing lethal shocks. RCCBs are designed to disconnect quickly enough to prevent injury caused by such shocks. The RCCBs at the site were rated I/P 63 A and O/P 30 mA.

Workers play a big part in eliminating and controlling electrical hazards at workplace. It should be made sure that they are given copies of safety meetings and emergency plans for electrical hazards. High voltages, grounding, electric current, arcing and the lack of guarding are among the inherent hazards of electricity which the “qualified” persons should be familiar with. Electrical protective equipment should always be used every time they work where there are potential electrical hazards. Specialized PPE may consist of rubber insulating gloves, sleeves, hoods, matting, line hose, blankets, and industrial protective helmets. Electrical extension cords are numerous on construction sites and

17

become damaged because of the rough conditions in which they are used. Inspect to ensure:

• All extension cords are three-wire cords; • The ground pin is on a male plug;

• There is no unbroken insulation on the cord; • End appliances (plug and receptacle) are gripped to insulation; • All wires are continuous and unbroken;

• All cords are protected from damage, likely to occur when passing through a door or window;

• Metal boxes with knockouts are not used on extension cords; • Plugs are dead-front (molded or screwed in place); • Romex (non-metallic sheathed cable) is not used as flexible cord;

• Cords are not stapled or hung from nails; • Bushing is passing through holes in covers or outlet boxes.

Also, check these items:

• Temporary lights are not supported by cords; • Bulb guards are used on temporary lights; • Electrical power tools with non-dead man switches have a magnetic restart (when

injury to the operator might result if motors were to restart following power failures); • Provisions are made to prevent machines from automatically restarting upon

restoration of power in place;

• Outlets do not have reversed polarity; • Power tools are double insulated or have a ground pin;

Guard all of exposed electric of more than 50 volts so no one can come in contact (receptacles, light-bulb sockets, bare wires, load center, switches). Guard by:

• Using approved enclosures; • Locating them in a room, vault or similar enclosure accessible only to qualified

persons;

• Arranging suitable permanent, substantial partitions or screens so only qualified persons have access to the space within reach of live parts;

• Locating them on a suitable balcony or platform that is elevated and arranged to exclude unqualified persons;

• Elevating them 8 feet or more above the working surface.

It's important to take the time prior to beginning work at construction sites each day. The fluid nature of the activities, along with the changing environment and high potential for damage can let these items become a hazard quickly.

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2.2.3 ORGANIZATIONAL CHART

Chairman and Managing Director

Director

Project Coordinator Senior Advisor, HSE

HSE Corporate Office HRD Head

Project Head(s)

Deputy Project Head(s)

Project HSE Head(s) Senior Engineer(s)

(Civil/Mechanical/Electrical)

Engineer(s)

(Civil/Mechanical/Electrical) HSE Engineer, Officer

HSE Supervisor Jr. Engineer, Supervisor

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2.2.4 PERSONAL PROTECTIVE EQUIPMENT

(P.P.E.)

Personal protective equipment (PPE) refers to protective clothing, helmets, goggles, or other garments or equipment designed to protect the wearer's body from injury. The hazards addressed by protective equipment include physical, electrical, heat, chemicals, biohazards, and airborne particulate matter. "Protective clothing" is applied to traditional categories of clothing, and "protective gear" applies to items such as pads, guards, shields, or masks, and others. The purpose of personal protective equipment is to reduce employee exposure to hazards when engineering and administrative controls are not feasible or effective to reduce these risks to acceptable levels. PPE is needed when there are hazards present. PPE has the serious limitation that it does not eliminate the hazard at source and may result in employees being exposed to the hazard if the equipment fails. Any item of PPE imposes a barrier between the wearer/user and the working environment. This can create additional strains on the wearer; impair their ability to carry out their work and create significant levels of discomfort. Any of these can discourage wearers from using PPE correctly, therefore placing them at risk of injury, ill-health or, under extreme circumstances, death. Good ergonomic design can help to minimize these barriers and can therefore help to ensure safe and healthy working conditions through the correct use of PPE.

PPE: Description: Use: Helmet Should be checked for IS

2925 mark. Colour coding of Helmets are as follows:

• White: Company Staff • Green: Safety Dept. • Red: Electrician • Yellow: Skilled

Workers • Yellow Load Carry:

Unskilled Workers • Blue: Subcontractor’s

Staff • Orange:

Visitors/Trainees • Grey: Mechanical • Black: Security

It is a form of protective gear worn to protect the head from injuries.

Safety Shoe It is a durable boot or shoe that has a protective reinforcement in the toe and usually combined with a mid sole plate to protect against punctures from below.

Protects the foot from falling objects or compression, and prevents penetration from below, and also is shock, heat and fire proof and provides better grip.

Hand gloves: • Rubber Gloves • Leather Gloves

Personal protective equipment worn over the hands. Used during general

Protects hands against cold or heat, damage by friction, abrasion or chemicals, and

20

• Cotton Gloves • Insulated Type

Gloves

material handling, masonry, hot work, electrical works.

disease or provides a guard for what a bare hand should not touch.

Safety Belt or Full body Harness with double lanyard

A belt or strap that attaches a person to an immovable object for safety. Some safety harnesses are used in combination with a shock absorber, which is used to regulate deceleration when the end of the rope is reached.

Protects a person from injury due to fall from a height. The harness is an attachment between a stationary and non-stationary object and is usually fabricated from rope, cable or webbing and locking.

Nose Mask It is a flexible pad held over the nose and mouth by elastic straps to protect against dusts encountered during construction activities, such as dusts from concrete, wood etc.

Prevents inhalation of dust and other minute foreign particles.

Ear Plugs An earplug is a device that is meant to be inserted in the ear canal to protect the user's ears from loud noises or the intrusion of water, foreign bodies, dust or excessive wind.

Protects the ear from loud noises or intrusion of foreign body.

Face Shield A face shield is a device used to protect wearer's entire face (or part of it) from impact hazard such as flying objects and sparks and chemical splashes.

Protects the face from getting hit by flying particles or sparks (during welding).

Goggles • White • Black

White goggles are used in chipping and pile breaking. Black goggles are used to protect the eyes from bright lights as well as particles, e.g. welding.

Protects the area surrounding the eye in order to prevent particulates, water or chemicals from striking the eyes.

Apron An apron is an outer protective garment that covers primarily the front of the body. It is a type of uniform.

Worn for hygienic reasons as well as in order to protect clothes from wear and tear. Used in hot works.

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2.3 CONSTRUCTION EQUIPMENTS

Construction equipments can be further classified into:

• Electrical Equipments, and • Mechanical Equipments

Electrical Equipments:

Electrical equipment at construction site includes Vibrators, Welding Machines, Diesel Generators etc.

• Vibrators: Concrete vibrators consolidate freshly poured concrete so that trapped air and excess water are released and the concrete settles firmly in place in the formwork. Improper consolidation of concrete can cause product defects, compromise the concrete strength, and produce surface blemishes such as bug holes and honeycombing. The rotation of the vibrators is in anti-clockwise direction, and the machine vibrates at the rate of 2900 RPM.

• Welding Machines: Welding is a fabrication or sculptural process that joins materials, usually metals or thermoplastics, by causing coalescence. This is often done by melting the work pieces and adding a filler material to form a pool of molten material (the weld pool) that cools to become a strong joint, with pressure sometimes used in conjunction with heat, or by itself, to produce the weld. These processes use a welding power supply to create and maintain an electric arc between an electrode and the base material to melt metals at the welding point. They can use either direct (DC) or alternating (AC) current, and consumable or non-consumable electrodes. The welding region is sometimes protected by some type of inert or semi-inert gas, known as a shielding gas, and filler material is sometimes used as well.. A welding power supply is a device that provides an electric current to perform welding. Welding usually requires high current (over 80 amperes) and it can need above 12,000 amperes in spot welding. Low current can also be used; welding two razor blades together at 5 amps with gas tungsten arc welding is a good example.

Concrete Vibrator

Welding Machine

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Mechanical Equipments:

In construction industry a lot of mechanical work has to be done. Uses of machinery reduce the amount of work and saves time. It also reduces number of workmen employed to do a particular job. In construction, mechanical equipments refer to primarily the heavy equipments. Heavy equipment refers to heavy-duty vehicles, specially designed for executing construction tasks, most frequently ones involving earthwork operations. They are also known as, heavy machines, heavy trucks, construction equipment, engineering equipment, heavy vehicles, or heavy hydraulics. They usually comprise five equipment systems: implement traction, structure, power train, control and information. Heavy equipment functions through the mechanical advantage of a simple machine, the ratio between input force applied and force exerted is multiplied. Currently most equipment use hydraulic drives as a primary source of motion.

List of mechanical equipment used during construction of Silveroak Estate, Rajarhat:

Equipment: Use: • Pumps: Moves fluids, or sometimes slurries, by mechanical action.

o Submersible Pump Prevents pump cavitations, a problem associated with a high elevation difference between pump and the fluid surface.

o Sump Pump Removes water that has accumulated in a water collecting sump basin

o Concrete Pump Transfers liquid concrete by pumping. o Diesel Pump Pumps fuel into the cylinders of a diesel engine, or a pump

functioning using diesel as the fuel. o Tullu Pump Mini monoblock universal pump. o Jumbo Drain Pump Pumping out dirty water mixed with soil.

• Hydra Lifts and lowers heavy materials and moves them horizontally.

• Dumper Carries bulk material on building sites. • Backhoe Used in excavations. • Batching Plant Combines various ingredients to form concrete. • Bar Cutting Machine Cuts reinforcing bars. • Bar Bending Machine Bends reinforcing bars. • Transit Mixer Transports and mixes concrete up to the construction site. • Air Compressor Converts power into kinetic energy by compressing and

pressurizing air, which can be released in quick bursts on command.

• Building Hoist Carries personnel, materials, and equipment quickly between the floors of a structure.

• Winch Machine Pulls in or lets out or otherwise adjusts the "tension" of a rope or wire rope.

• Weight Batcher Batching plant in which all ingredients for a concrete mix are measured by weight.

• Poclain Excavator, etc. Used in excavation

23

Some of the equipments at work in the site:

Concrete Mixer Truck:

Batching Plant:

Building Hoist:

24

Backhoe at work in Tower 6:

Backhoe loader and pumps:

25

2.4 CONSTRUCTION MATERIALS:

CONCRETE:

Concrete is a mixture of cement, sand, stone aggregates and water. A cage of steel rods used

together with the concrete mix leads to the formation of Reinforced Cement Concrete

popularly known as RCC.

Concrete has two main stages

1) Fresh Concrete

2) Hardened Concrete

Fresh Concrete should be stable and should not segregate or bleed during transportation and

placing when it is subjected to forces during handling operations of limited nature. The mix

should be cohesive and mobile enough to be placed in the form around the reinforcement and

should be able to cast into the required shape without loosing continuity or homogeneity

under the available techniques of placing the concrete at a particular job. The mix should be

amenable to proper and through compaction into a dense, compact concrete with minimum

voids under the existing facilities of compaction at the site. A best mix from the point of view

of campactibility should achieve a 99 percent elimination of the original voids present. The

stability of a concrete mix requires that it should not segregate and bleed during the

transportation and placing. Segregation can be defined as separating out of the ingredients of

a concrete mix, so that the mix is no longer in a homogeneous condition. Only the stable

homogeneous mix can be fully compacted. The segregation depends upon the handling and

placing operations. The tendency to segregate, amount of coarse aggregate, and with the

increased slump. The tendency to segregate can be minimized by:

• Reducing the height of drop by concrete.

• Not using the vibration as a means of spreading a heap of of concrete into a level

mass over a large area.

• Reducing the continued vibration over a longer time, as the coarse aggregate tends to

settle to the bottom and the scum would rise to the surface.

• Adding small quantity of water which improves cohesion of the mix.

Bleeding is due to the rise of water in the mix to the surface because of the inability of the

solid particles in the mix to hold all the mixing water during settling of particles under the

26

effect of compaction. The bleeding causes formation of a porous, weak and non durable

concrete layer at the top of placed concrete. In case of lean mixes bleeding may create

capillary channels increasing the permeability of the concrete. When the concrete is placed in

different layers and each layer is compacted after allowing certain time to lapse before the

next layer is laid, the bleeding may cause a plane of weakness between two layers. Any

laitance formed should be removed by brushing and washing before a new layer is added.

Over compacting the surface should be avoided.

Hardened Concrete One of the most important properties of the hardened concrete is its

strength which represents the ability if concrete to resist forces. If the nature of the force is to

produce compression, the strength is termed compressive strength. The compressive strength

of hardened concrete is generally considered to be the most important property and is often

taken as the index of the overall quality of concrete. The strength can indirectly give an idea

of the most of the other properties of concrete which are related directly to the structure of

hardened cement paste. A stronger concrete is dense, compact, impermeable and resistant to

weathering and to some chemicals. However, a stronger concrete may exhibit higher drying

shrinkage with consequent cracking, due to the presence of higher cement content. Some of

the other desirable properties like shear and tensile strengths, modulus of elasticity, bond,

impact and durability etc. are generally related to compressive strength. As the compressive

strength can be measured easily on standard sized cube or cylindrical specimens, it can be

specified as a criterion for studying the effect of any variable on the quality of concrete.

However, the concrete gives different values of any property under different testing

conditions. Hence method of testing, size of specimen and the rate of loading etc. are

stipulated while testing the concrete to minimize the variations in test results. The statistical

methods are commonly used for specifying the quantitative value of any particular property

of hardened concrete.

Compressive strength of concrete is defined as the load which causes the failure of specimen,

per unit area of cross-section in uniaxial compression under given rate of loading. The

strength of concrete is expressed as N/mm2. The compressive strength at 28 days after

casting is taken as a criterion for specifying the quality of concrete. This is termed as grade of

concrete. IS 456 – 2000 stipulates the use of 150 mm cubes. Tensile strength of concrete is

low; it ranges from 8-12 per cent of its compressive strength. An average value of 10 per cent

is generally adopted. Shear strength is generally 12-13 per cent of its compressive strength.

The concrete subjected to bending and shear stress is accompanied by tensile and

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compressive stresses. The shear failures are due to resulting diagonal tension. Bond strength

is taken as 10 per cent of its compressive strength. The resistance of concrete to the slipping

of reinforcing bars embedded in concrete is called bond strength. The bond strength is

provided by adhesion of hardened cement paste, and by the friction of concrete and steel. It is

also affected by shrinkage of concrete relative to steel.

Facts about Cement and Concrete

1) Water required by 1 bag of cement is something in the range of 25-28 litres

2) Quality of concrete has nothing to do with its color.

3) The mortar / concrete should be consumed as early as possible after addition of water to it.

The hydration of cement starts the moment water is added to it. As the hydration progresses

the cement paste starts stiffening and loses its plasticity. The concrete should not be disturbed

after this. Normally, this is about 45 – 50 minutes.

4) MPa is abbreviated form of mega Pascal, which is a unit of pressure. 1 MPa is equivalent

to a pressure of 10Kg /cm2. The strength of concrete & cement is expressed in terms of

pressure a standard cube can withstand. The Ordinary Portland Cement, commonly called

OPC is available in three grades namely 33, 43 & 53 grades. Thus, for 43 grade cement

standard cement & sand mortar cube would give a minimum strength of 43 MPa or 430 Kg

/cm2 when tested under standard curing conditions for 28 days. Compressive Strength of

Concrete depends on following factors:

w/c ratio Characteristics of cement Characteristics of aggregates

Time of mixing Degree of compaction Temperature and period of curing

Age of concrete Air entertainment Conditions of testing

Precautions for water to be used in concrete

It is good to use potable quality of water, and

seawater isn’t recommended.

It should be free from impurities and harmful

ingredients.

The water fit for mixing is fit for curing too Ensure that water is measured and added.

Low water to cement ratio is essential for good

performance of the structure in the long run.

Use of too much or too little water for mixing, or

water carelessly added during mixing

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Using concrete which has already begun to set. Inadequate compaction of concrete

Too much troweling of the concrete surface. Incomplete mixing of aggregate with cement

Use of dirty aggregate or water containing earthy

matter, clay or lime.

Common Reasons for lack of quality in concrete

work

Improper grading of aggregates resulting in

segregation or bleeding of concrete.

Placing of concrete on a dry foundation without

properly wetting it with water.

Use of minimum quantity of mixing water,

consistent with the degree of workability

required to enable easy placing and compaction

of concrete, is advisable.

Leaving the finished concrete surface exposed to

sun and wind during the first ten days after

placing without protecting it and keeping it damp

by proper methods of curing.

CONCRETING AT CONSTRUCTION SITE:

Construction joints are the joints provided between successive pours of concrete that have

been carried out after a time lag. As far as possible the construction joints should be avoided

and every care should be taken to keep their numbers minimal. Since, presence of these joints

creates a plane of weakness within the concrete body, these joints should be preplanned and

their location should be such that they are at places where they are subjected to minimum

bending moment and minimum shear force.

POURING AND CONSOLIDATION: Concrete (M20) was used for all works in column,

beams and slabs. It was well consolidated by vibrating using portable mechanical vibrators.

Care was taken to ensure that concrete is not over vibrated so as to cause segregation. The

layers of concrete are so placed that the bottom layer does not finally set before the top layer

is placed. The vibrators maintain the whole of concrete under treatment in an adequate state

of agitation, such that deaeration and effective compaction is attained at a state commensurate

with the supply of concrete from the mixers. The vibrator continue during the whole period

occupied by placing of concrete, the vibrators being adjusted so that the centre vibrations

approximate to the centre of the mass being compacted at the time of placing. Shaking of

reinforcement for the purpose of compaction should be avoided. Compaction shall be

completed before initial setting starts i.e. within thirty minute of addition of water to the dry

mixture. The concrete was deposited in its final position in a manner to preclude segregation

of ingredients. In case of column and walls, the shuttering was so adjusted that the vertical

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drop of concrete is not more than 1.5 m at a time. In case of concreting of slabs and beams,

the pipe from the batching plant was directly taken to the closest point.

Method of Concreting:

Concrete mix design for different structure should be as per notes in the specific approved

drawing. For design mix concrete, the mix shall be designed to provide the grade of concrete

having the required strength, workability & durability requirements given in IS 456 for each

grade of concrete taking into account the type of cement, minimum cement content and

maximum W/C ratio conforming to exposure conditions as per tender specifications. Mix

design and preliminary tests are not necessary for nominal mix concrete (M5, M7.5, M10,

M15, M20 as Specified in IS 456 - Table 9). However works tests shall be carried out as per

IS 456. No concreting shall be done without the approval of engineer. Prior notice shall be

given before start of concreting. Cement shall be measured by weight in weigh batching

machines of an approved type; aggregate shall be measured by volume/weight. The machines

shall be kept clean and in good condition and shall be checked and adjusted for accuracy at

regular intervals when required by the engineer. Material shall be weighed within 2.5%

tolerances, inclusive of scale and operating errors. The weigh batching machines shall

discharge efficiently so that no materials are retained. Concrete shall be mixed in mechanical

mixers of an approved type. In no case shall the mixing of each batch of concrete continue for

less than 2 minutes. The water to be added in concrete shall be adjusted based on moisture

contents in fine and coarse aggregates. During hot and cold weather, suitable methods to

reduce the loss of water by evaporation in hot weather and heat loss in cold weather will be

adopted as per procedure set out in IS: 786. The compaction of concrete will be done by

immersion type needle vibrator which shall be inserted into concrete in vertical position not

more than 450 mm apart. Vibration will be applied systematically to cover all areas

immediately after placing concrete and will be stopped when the concrete flattens and takes

up a glistening appearance, or rise of entrapped air ceases or coarse aggregate blends into the

surface but does not completely disappear. The vibrator shall be slowly withdrawn to ensure

closing of the hole resulting from insertion. Unless otherwise approved, continuous

concreting shall be done to the full thickness of foundation rafts, slabs, beams & similar

members. For placing on slope, concreting will be started at the bottom and moved upwards.

Concrete shall not fall from a height of more than 1m to avoid segregation. Special care shall

be taken to guarantee the finish and water-tightness of concrete for liquid retaining structures,

underground structures and those if specifically mentioned. The minimum level of surface

30

finish for liquid retaining structures shall be Type F-2 and it shall be hydrotested to approved

procedure. Any leakage during hydrotest or subsequently during defect liability period, if

occurred shall be effectively stopped either by cement /epoxy pressure grouting or any other

approved method. Curing of concrete with approved water shall start after completion of

initial setting time of concrete and in hot weather after 3 hours. Concrete will be cured for a

minimum period of seven days when OPC with high water cement ratio is used, curing for

minimum 10 days in hot weather or low water cement ratio is used and where mineral

admixture used minimum curing period is 14 days. Freshly laid concrete shall be protected

from rain by suitable covering. Curing shall be done by continuous sprays or ponded water or

continuously saturated coverings of sacking canvas, hessian or other absorbent material for

the period of complete hydration with a minimum of 7 days. Curing shall also be done by

covering the surface with an impermeable material such as Polyethylene, which shall be well

sealed and fastened. Alternatively curing compound of approved make can be applied

immediately after stripping of formwork. The workability of concrete shall be checked by the

site engineer. The prepared surface shall be inspected and certified in pour card. Staining or

discoloration shall be washed out. If surface is not upto the acceptable standard, as per IS

456, cement wash is to be provided on exposed concrete surface of foundation, beam,

column, wall etc. All blemishes and defect if any shall be rectified immediately after the

removal of formwork. For each sample of concrete pour 150mm cubes shall be prepared and

cured. 3 nos shall be crushed at 7days and other 3 nos at 28 days. Record shall be made for

each test in enclosed formats as per ITP. PVC water stoppers shall be provided in

construction joints as per AFC drawing confirming to IS-12200. Prior approval shall be taken

for location & material. Alternatively G.I. sheet of 200 mm wide and 18 gauge thick shall

also be used for the same with the approval of Engineer.

CEMENT:

Portland cement is composed of calcium silicates and aluminate and aluminoferrite It is

obtained by blending predetermined proportions limestone clay and other minerals in small

quantities which is pulverized and heated at high temperature – around 1500 deg centigrade

to produce ‘clinker’. The clinker is then ground with small quantities of gypsum to produce a

fine powder called Ordinary Portland Cement (OPC). When mixed with water, sand and

stone, it combines slowly with the water to form a hard mass called concrete. Cement is a

hygroscopic material meaning that it absorbs moisture In presence of moisture it undergoes

31

chemical reaction termed as hydration. Therefore cement remains in good condition as long

as it does not come in contact with moisture. If cement is more than three months old then it

should be tested for its strength before being taken into use. The Bureau of Indian Standards

(BIS) has classified OPC in three different grades The classification is mainly based on the

compressive strength of cement-sand mortar cubes of face area 50 cm2 composed of 1 part of

cement to 3 parts of standard sand by weight with a water-cement ratio arrived at by a

specified procedure. The grades are

(i) 33 grade

(ii) 43 grade

(iii) 53 grade

The grade number indicates the minimum compressive strength of cement sand mortar in

N/mm2 at 28 days, as tested by above mentioned procedure. Portland Pozzolana Cement

(PPC) is obtained by either intergrinding a pozzolanic material with clinker and gypsum, or

by blending ground pozzolana with Portland cement. Nowadays good quality fly ash is

available from Thermal Power Plants, which are processed and used in manufacturing of

PPC.

Advantages of using Portland pozzolana cement over OPC: Pozzolana combines with lime

and alkali in cement when water is added and forms compounds which contribute to strength,

impermeability and sulphate resistance. It also contributes to workability, reduced bleeding

and controls destructive expansion from alkali-aggregate reaction. It reduces heat of

hydration thereby controlling temperature differentials, which causes thermal strain and

resultant cracking n mass concrete structures like dams. The colour of PPC comes from the

colour of the pozzolanic material used. PPC containing fly ash as a pozzolana will invariably

be slightly different colour than the OPC.One thing should be kept in mind that is the quality

of cement depends upon the raw materials used and the quality control measures adopted

during its manufacture, and not on the shade of the cement. The cement gets its colour from

the nature and colour of raw materials used, which will be different from factory to factory,

and may even differ in the different batches of cement produced in a factory. Further, the

colour of the finished concrete is affected also by the colour of the aggregates, and to a lesser

extent by the colour of the cement. Preference for any cement on the basis of colour alone is

technically misplaced.

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Setting of Cement: When water is mixed with cement, the paste so formed remains pliable

and plastic for a short time. During this period it is possible to disturb the paste and remit it

without any deleterious effects. As the reaction between water and cement continues, the

paste loses its plasticity. This early period in the hardening of cement is referred to as

‘setting’ of cement. Initial set is when the cement paste loses its plasticity and stiffens

considerably. Final set is the point when the paste hardens and can sustain some minor load.

Both are arbitrary points and these are determined by Vicat needle penetration resistance.

Slow or fast setting normally depends on the nature of cement. It could also be due to

extraneous factors not related to the cement. The ambient conditions play an important role.

In hot weather, the setting is faster, in cold weather, setting is delayed Some types of salts,

chemicals, clay, etc if inadvertently get mixed with the sand, aggregate and water could

accelerate or delay the setting of concrete.

Storage of Cement: It needs extra care or else can lead to loss not only in terms of financial

loss but also in terms of loss in the quality. Following are the don’ts that should be followed:

(i) Do not store bags in a building or a godown in

which the walls, roof and floor are not completely

weatherproof.

(ii) Do not store bags in a new warehouse until

the interior has thoroughly dried out.

(iii) Do not be content with badly fitting windows

and doors, make sure they fit properly and ensure

that they are kept shut.

(iv) Do not stack bags against the wall. Similarly,

don’t pile them on the floor unless it is a dry

concrete floor. If not, bags should be stacked on

wooden planks or sleepers.

(v) Do not forget to pile the bags close together (vi) Do not pile more than 15 bags high and

arrange the bags in a header-and-stretcher

fashion.

(vii) Do not disturb the stored cement until it is to

be taken out for use.

(viii) Do not take out bags from one tier only.

Step back two or three tiers.

(ix) Do not keep dead storage. The principle of

first-in first-out should be followed in removing

bags.

(x) Do not stack bags on the ground for

temporary storage at work site. Pile them on a

raised, dry platform and cover with tarpaulin or

polythene sheet.

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COARSE AGGREGATE:

Coarse aggregate for the works should be river gravel or crushed stone .It should be hard,

strong, dense, durable, clean, and free from clay or loamy admixtures or quarry refuse or

vegetable matter. The pieces of aggregates should be cubical, or rounded shaped and should

have granular or crystalline or smooth (but not glossy) non-powdery surfaces. Aggregates

should be properly screened and if necessary washed clean before use. Coarse aggregates

containing flat, elongated or flaky pieces or mica should be rejected. The grading of coarse

aggregates should be as per specifications of IS-383. After 24-hrs immersion in water, a

previously dried sample of the coarse aggregate should not gain in weight more than 5%.

Aggregates should be stored in such a way as to prevent segregation of sizes and avoid

contamination with fines. Depending upon the coarse aggregate color, there quality can be

determined as:

Black Very good quality

Blue Good quality

Whitish Bad quality

FINE AGGREGATE:

Aggregate which is passed through 4.75 IS Sieve is termed as fine aggregate. Fine aggregate

is added to concrete to assist workability and to bring uniformity in mixture. Usually, the

natural river sand is used as fine aggregate. Important thing to be considered is that fine

aggregates should be free from coagulated lumps. Grading of natural sand or crushed stone

i.e. fine aggregates shall be such that not more than 5 percent shall exceed 5 mm in size, not

more than 10% shall IS sieve No. 150 not less than 45% or more than 85% shall pass IS sieve

No. 1.18 mm and not less than 25% or more than 60% shall pass IS sieve No. 600 micron.

ADMIXTURES:

Admixtures are those ingredients/materials that are added to cement, water, and aggregate

mixture during mixing in order to modify or improve the properties of concrete for a required

application. Broadly the following five changes can be expected by adding an admixture

(i) Air entertainment (ii) Water reduction for better quality

(iii) Acceleration of strength development (iv) Improving the workability

(v) Water retention

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Some of the important purposes for which the admixtures could be used are

1. Acceleration of the rate of strength

development at early ages

2. Retardation of the initial setting of the concrete

3. Increase in strength 4. Improvement in workability

5. Reduction in heat of evolution 6. Production of coloured concrete or mortar

7. Control of alkali-aggregate expansion 8. Reduction in the capillary flow of water and

increase in impermeability to liquids

9. Improvement of pumpability and reduction

in segregation in grout mixtures

10. Increase in durability or in resistance to special

conditions of exposure

The best way to test the admixture is by making trial mixes with the concrete materials to be

used on the job and carefully observing and measuring the change in the properties. This way

the compatibility of the admixture and the materials to be used, as well the effects of the

admixture on the properties of fresh and hardened concrete can be observed. The amount of

admixture recommended by the manufacturer or the optimum quantity determined by

laboratory tests should be used.

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2.5 PLANNING:

Construction planning is a fundamental and challenging activity in the management and

execution of construction projects. It involves the choice of technology, the definition of

work tasks, the estimation of the required resources and durations for individual tasks, and

the identification of any interactions among the different work tasks. A good construction

plan is the basis for developing the budget and the schedule for work. Developing the

construction plan is a critical task in the management of construction, even if the plan is not

written or otherwise formally recorded. In addition to these technical aspects of construction

planning, it may also be necessary to make organizational decisions about the relationships

between project participants and even which organizations to include in a project. For

example, the extent to which sub-contractors will be used on a project is often determined

during construction planning. The following tasks are done in construction planning:

• Choice of Technology and Construction Method: As in the development of

appropriate alternatives for facility design, choices of appropriate technology and

methods for construction are often ill-structured yet critical ingredients in the success

of the project. For example, a decision whether to pump or to transport concrete in

buckets will directly affect the cost and duration of tasks involved in building

construction. A decision between these two alternatives should consider the relative

costs, reliabilities, and availability of equipment for the two transport methods.

• Defining Work Tasks: At the same time that the choice of technology and general

method are considered, a parallel step in the planning process is to define the various

work tasks that must be accomplished. These work tasks represent the necessary

framework to permit scheduling of construction activities, along with estimating the

resources required by the individual work tasks and any necessary precedence or

required sequence among the tasks. The terms work "tasks" or "activities" are often

used interchangeably in construction plans to refer to specific, defined items of work.

• Defining Precedence Relationships among Activities: Once work activities have been

defined, the relationships among the activities can be specified. Precedence relations

between activities signify that the activities must take place in a particular sequence.

Numerous natural sequences exist for construction activities due to requirements for

36

structural integrity, regulations, and other technical requirements. For example, design

drawings cannot be checked before they are drawn.

• Estimating Activity Durations: In most scheduling procedures, each work activity has

associated time duration. These durations are used extensively in preparing a

schedule. A straightforward approach to the estimation of activity durations is to keep

historical records of particular activities and rely on the average durations from this

experience in making new duration estimates. Since the scopes of activities are

unlikely to be identical between different projects, unit productivity rates are typically

employed for this purpose.

• Estimating Resource Requirements for Work Activities: In addition to precedence

relationships and time durations, resource requirements are usually estimated for each

activity. Since the work activities defined for a project are comprehensive, the total

resources required for the project are the sum of the resources required for the various

activities. By making resource requirement estimates for each activity, the

requirements for particular resources during the course of the project can be

identified. Potential bottlenecks can thus be identified, and schedule, resource

allocation or technology changes made to avoid problems.

• Coding Systems: One objective in many construction planning efforts is to define the

plan within the constraints of a universal coding system for identifying activities.

Each activity defined for a project would be identified by a pre-defined code specific

to that activity. The use of a common nomenclature or identification system is

basically motivated by the desire for better integration of organizational efforts and

improved information flow. In particular, coding systems are adopted to provide a

numbering system to replace verbal descriptions of items. These codes reduce the

length or complexity of the information to be recorded. A common coding system

within an organization also aids consistency in definitions and categories between

projects and among the various parties involved in a project. Common coding systems

also aid in the retrieval of historical records of cost, productivity and duration on

particular activities. Finally, electronic data storage and retrieval operations are much

more efficient with standard coding systems.

37

2.6 SURVEYING Surveying or land surveying is the technique, profession, and science of accurately determining the

terrestrial or three-dimensional position of points and the distances and angles between them,

commonly practiced by licensed surveyors, and members of various building professions. These

points are usually on the surface of the Earth, and they are often used to establish land maps and

boundaries for ownership, locations (building corners, surface location of subsurface features) or

other governmentally required or civil law purposes (property sales). Surveyors determine the

position of objects by measuring angles and distances, along with various factors that can affect the

accuracy of their observations. From this information, they can calculate more advanced constructs

such as vectors, bearings, co-ordinates, elevations, areas, volumes, plans and maps. Measurements

are also often split into horizontal and vertical components to simplify calculation. Most surveys

points are measured relative to previously measured points. This forms a reference or control

network where each point can be used by a surveyor to determine their own position when beginning

a new survey. Survey points are usually marked on the earth's surface by an object ranging from

small nails driven into the ground to large beacons that can be seen from long distances. The

surveyor can set up their instruments on this position and measure to nearby objects. Sometimes a

tall, distinctive feature such as a steeple or radio aerial has its position calculated a reference point

that angles can be measured against.

METHODS OF SURVEYING:

Triangulation is a method where a surveyor first needs to know the horizontal distance between two

of the objects, known as the baseline. Then the height, distances and angular position of other objects

can be derived, as long as they are visible from one of the original objects. High-accuracy transits or

theodolites were used for this work, and angles between objects were measured repeatedly for

increased accuracy.

Offsetting is an alternate method of determining position of objects, and was often used to measure

imprecise features such as riverbanks. The surveyor would mark and measure two known positions

on the ground roughly parallel to the feature, and mark out a baseline between them. At regular

intervals, a distance was measured at right angles from the first line to the feature. The measurements

could then be plotted on a plan or map, and the points at the ends of the offset lines could be joined

to show the feature.

38

Traversing is a common method of surveying smaller areas. Starting from an old reference mark or

known position, the surveyor creates a network of reference marks covering the area to be surveyed.

They then measure bearings and distances between the reference marks, and to the features to be

surveyed. Most traverses form a loop pattern or link between two prior reference marks to allow the

surveyor to check their measurements are correct.

TYPES OF SURVEYING:

Specializations of surveying may be classed differently according to the local professional

organization or regulatory body, but may be broadly grouped as follows.

As-built survey: a survey carried out during or

immediately after a construction project for record,

completion evaluation and payment purposes.

Cadastral or Boundary surveying: a survey that

establishes or re-establishes boundaries of a parcel

using its legal description.

Compass and tape survey: perhaps the simplest type,

as the name suggests, a tape and a compass are used

in this type of surveying.

Control surveying: Control surveys establish

reference points that surveyors can use to establish

their own position at the start of future surveys.

Deformation survey: a survey to determine if a

structure or object is changing shape or moving.

Leveling: either finds the elevation of a given point

or establish a point at a given elevation.

Engineering surveying: those surveys associated with

the engineering design (topographic, layout and as-

built) often requiring geodetic computations beyond

normal civil engineering practice.

Tape survey: accurate for distance, lacked

substantially in their accuracy of measuring angle and

bearing standards that are practiced by professional

land surveyors.

Hydrographic survey: a survey conducted with the

purpose of mapping the shoreline and bed of a body

of water for navigation, engineering, or resource

management purposes.

Dimensional control survey: This is a type of Survey

commonly used in the oil and gas industry to replace

old or damaged pipes on a like-for-like basis, the

advantage this type is that the instrument used to

conduct the survey does not need to be level.

Measured survey: a building survey to produce plans

of the building.

Topographic survey measures the elevation of points

on a particular piece of land, and presents them as

contour lines on a plot.

Structural survey: a detailed inspection to report upon

the physical condition and structural stability of a

structure.

Foundation survey: a survey done to collect the

positional data on a foundation that has been poured

and is cured.

39

MODERN SURVEYING INSTRUMENTS:

Theodolite: A theodolite is a precision instrument for measuring

angles in the horizontal and vertical planes. Theodolites are used

mainly for surveying applications, and have been adapted for

specialized purposes in fields like meteorology and rocket launch

technology. Theodolites may be either transit or non-transit. Transit

theodolites (or just "transits") are those in which the telescope can be

inverted in the vertical plane, whereas the rotation in the same plane is

restricted to a semi-circle for non-transit theodolites. Some types of

transit theodolites do not allow the measurement of vertical angles.

Total Stations: A total station is an electronic/optical instrument used

in modern surveying and building construction. The total station is an

electronic theodolite (transit) integrated with an electronic distance

meter (EDM) to read slope distances from the instrument to a

particular point. Most modern total station instruments measure angles

by means of electro-optical scanning of extremely precise digital bar-

codes etched on rotating glass cylinders or discs within the instrument.

Measurement of distance is accomplished with a modulated microwave or infrared carrier signal,

generated by a small solid-state emitter within the instrument's optical path, and reflected by a prism

reflector or the object under survey. Some total stations can measure the coordinates of an unknown

point relative to a known coordinate can be determined using the total station as long as a direct line

of sight can be established between the two points. Some models include internal electronic data

storage to record distance, horizontal angle, and vertical angle measured, while other models are

equipped to write these measurements to an external data collector, such as a hand-held computer.

Theodolite:

Total Station:

40

SURVEYING AT THE SITE:

A Reconnaissance Survey was conducted, which gave the following information regarding the site:

• Site is located within 2.4 km of Kolkata Airport and within 2 km of City Centre 2.

• The site is a water logged area hence dewatering should be done.

• Leveling is required since the land is not uniformly level.

• The ground is soft.

• Labour available near the site.

• Houses are located near the site.

Post the Reconnaissance Survey, a Detailed Survey was conducted, to accurately determine the

boundaries of the required areas of the site with the help of theodolites and total stations.

41

2.7 QUALITY CONTROL

Utility systems need infrastructure to last as long as possible. One way to ensure longevity is

through quality control. To have good quality control in construction projects is to perform

good inspections. Remember, you can inspect it now or fix it later. Quality control is

critically important to a successful construction project and should be adhered to throughout a

project from conception and design to construction and installation. Inspection during

construction will prevent costly repairs after the project is completed. The inspector,

engineer, contractor, funding agency, permit agency, and system personnel must work

together to inspect, document, and correct deficiencies.

What is Quality Control?

For construction projects, quality control means making sure things are done according to the

plans, specifications, and permit requirements. One of the best ways to assure good

construction projects is to use an inspector. The first step an inspector should take is to

become familiar with the plans, specification, and permit requirements and, equally

important, to have some common sense. Quality control during all construction phases needs

to be better, and the utility system needs to know what is being installed while the work is

being done.

Roles and functions of various departments of Quality Management

Quality Assurance: The primary function of quality assurance is to obtain completed

construction that meets all contract requirements. Assurance is defined as a degree of

certainty. Quality assurance personnel continually assure--or make certain--that the

contractor's work complies with contract requirements.

Quality Assurance Personnel: The role of quality assurance personnel is to assure that the

CQC system is functioning properly. To do this, QA personnel:

• Examine the quality control methods being used to determine if the contractor is properly

controlling design activities in design-build contracts.

• Examine the quality control methods being used to determine if the contractor is properly

controlling construction activities.

• Make certain that the necessary changes are made in the contractor's QC system, if

excessive construction deficiencies occur.

42

• Assist the contractor in understanding and implementing the contract requirements.

• Examine ongoing and completed work.

• Review QC documentation to assure adequacy.

Contractor Quality Control: The primary function of CQC is the successful execution of a

realistic plan to ensure that the required standards of quality construction will be met. In

CQC, the contractor defines procedures to manage and control his own, designer of record,

consultant, architect-engineer, all subcontractor and all supplier activities so that the

completed project complies with contract requirements. The design QC plan shall be

managed by a Design QC Manager who has verifiable engineering or architectural design

experience or is a registered engineer or architect. The Design QC Manager is under the

supervision of the QC Manager.

Quality Control Personnel: CQC or Contractor Quality Control is a contractor responsibility.

This includes:

• Produce the quality specified in the plans and specifications and for design-build contracts

in the Request for Proposal, as well as the contractor's accepted proposal,

• Develop and maintain an effective CQC system,

• Perform all control activities and tests, and

• Prepare acceptable documentation of CQC activities.

The contractor also is required to place a competent representative onsite to oversee the CQC

system. He must have full authority to act for the contractor on CQC matters. His

responsibilities include workmanship, methods, and techniques to ensure that all work is

performed properly by qualified and careful craftsmen. For design-build contracts,

responsibility also includes design quality and the performance of constructability,

operability and environmental review of the design. At our site, Simplex Infrastructures Ltd.

being the contractor, the quality control was done by them.

43

Test conducted on site for quality control

TESTS ON CONCRETE:

SLUMP TEST

Slump test is used to determine the workability of fresh concrete. Slump test as per IS: 1199 –

1959 is followed.The apparatus used for Slump Test are Slump Cone and Tamping Rod.

• APPARATUS:

Abram’s Cone (Top diameter: 10 cm, Bottom Diameter: 20 cm, Height: 30 cm)

Tamping Rod (Diameter: 16 mm)

• PROCEDURE:

i) The internal surface of the mould is thoroughly cleaned and applied with a light

coat of oil.

ii) The mould is placed on a smooth, horizontal, rigid and nonabsorbent surface.

iii) The mould is then filled in four layers with freshly mixed concrete, each

approximately to one-fourth of the height of the mould.

iv) Each layer is tamped 25 times by the rounded end of the tamping rod (strokes are

distributed evenly over the cross section).

v) After the top layer is rodded, the concrete is struck off the level with a trowel. Once

the cone is filled and topped off [ excessive concrete from top is cleared ] raise the

cone within 5-10 seconds.

vi) The mould is removed from the concrete immediately by raising it slowly in the

vertical direction.

vii) The difference in level between the height of the mould and that of the highest

point of the subsided concrete is measured.

viii) This difference in height in mm is the slump of the concrete.

• REPORTING OF RESULTS:

The slump measured should be recorded in mm of subsidence of the specimen during

the test. Any slump specimen, which collapses or shears off laterally gives incorrect

result and if this occurs, the test should be repeated with another sample. If, in the

repeat test also, the specimen shears, the slump should be measured and the fact that

the specimen sheared, should be recorded. In case of a dry sample, slump will be in

the range of 25-50 mm that is 1-2 inches. But in case of a wet concrete, the slump

may vary from 150-175 mm or say 6-7 inches. So the value of slump is specifically

mentioned along the mix design and thus it should be checked as per your location.

Slump depends on many factors like properties of concrete ingredients

etc. Also temperature has its effect on slump value. So all these para

kept in mind when deciding the ideal slump. Value of Slump can be increased by the

addition of chemical admixtures like mid

(super-plasticizers) without changing the water/cement ratio.

COMPRESSION TEST

Out of many test applied to the concrete, this is the utmost important which gives an idea

about all the characteristics of concrete. By this single test one judges that whether

Concreting has been done properly or not. For cube test two t

of 15 cm X 15 cm X 15 cm or 10cm X 10 cm x 10 cm depending upon the size of aggregate

are used. For most of the works cubical moulds of size 15 cm x 15cm x 15 cm are commonly

used. This concrete is poured in the mould and tem

After 24 hours these moulds are removed and test specimens are put in water for curing. The

top surface of these specimens should be made even and smooth. This is done by putting

cement paste and spreading smooth

by compression testing machine after 7 days curing or 28 days curing. Load should be

applied gradually at the rate of 140 kg/cm2 per minute till the Specimens fails. Load at the

failure divided by area of specimen gives the compressive strength of concrete.

the procedure for Compressive strength test of Concrete Cubes:

• APPARATUS:

Compression testing machine

• PREPARATION OF CUBE SPECIMENS:

making these test specimens are from the same concrete used in the field.

• SPECIMEN:

6 cubes of 15 cm size Mix. M15 or above

• MIXING:

mentioned along the mix design and thus it should be checked as per your location.

Slump depends on many factors like properties of concrete ingredients

etc. Also temperature has its effect on slump value. So all these para

kept in mind when deciding the ideal slump. Value of Slump can be increased by the

addition of chemical admixtures like mid-range or high-range water reducing agents

plasticizers) without changing the water/cement ratio.

Out of many test applied to the concrete, this is the utmost important which gives an idea

about all the characteristics of concrete. By this single test one judges that whether

Concreting has been done properly or not. For cube test two types of specimens either cubes

of 15 cm X 15 cm X 15 cm or 10cm X 10 cm x 10 cm depending upon the size of aggregate

are used. For most of the works cubical moulds of size 15 cm x 15cm x 15 cm are commonly

used. This concrete is poured in the mould and tempered properly so as not to have any voids.

After 24 hours these moulds are removed and test specimens are put in water for curing. The

top surface of these specimens should be made even and smooth. This is done by putting

cement paste and spreading smoothly on whole area of specimen. These specimens are tested

by compression testing machine after 7 days curing or 28 days curing. Load should be

applied gradually at the rate of 140 kg/cm2 per minute till the Specimens fails. Load at the

ea of specimen gives the compressive strength of concrete.

the procedure for Compressive strength test of Concrete Cubes:

Compression testing machine

PREPARATION OF CUBE SPECIMENS: The proportion and material for

specimens are from the same concrete used in the field.

6 cubes of 15 cm size Mix. M15 or above

44

mentioned along the mix design and thus it should be checked as per your location.

Slump depends on many factors like properties of concrete ingredients – aggregates

etc. Also temperature has its effect on slump value. So all these parameters should be

kept in mind when deciding the ideal slump. Value of Slump can be increased by the

range water reducing agents

Out of many test applied to the concrete, this is the utmost important which gives an idea

about all the characteristics of concrete. By this single test one judges that whether

ypes of specimens either cubes

of 15 cm X 15 cm X 15 cm or 10cm X 10 cm x 10 cm depending upon the size of aggregate

are used. For most of the works cubical moulds of size 15 cm x 15cm x 15 cm are commonly

pered properly so as not to have any voids.

After 24 hours these moulds are removed and test specimens are put in water for curing. The

top surface of these specimens should be made even and smooth. This is done by putting

ly on whole area of specimen. These specimens are tested

by compression testing machine after 7 days curing or 28 days curing. Load should be

applied gradually at the rate of 140 kg/cm2 per minute till the Specimens fails. Load at the

ea of specimen gives the compressive strength of concrete. Following are

The proportion and material for

specimens are from the same concrete used in the field.

45

Mix the concrete either by hand or in a laboratory batch mixer

• HAND MIXING:

(i) Mix the cement and fine aggregate on a water tight none-absorbent platform until

the mixture is thoroughly blended and is of uniform color.

(ii) Add the coarse aggregate and mix with cement and fine aggregate until the coarse

aggregate is uniformly distributed throughout the batch.

(iii) Add water and mix it until the concrete appears to be homogeneous and of the

desired consistency

• SAMPLING:

(i) Clean the mounds and apply oil

(ii) Fill the concrete in the molds in layers approximately 5cm thick

(iii) Compact each layer with not less than 35strokes per layer using a tamping rod

(steel bar 16mm diameter and 60cm long, bullet pointed at lower end)

(iv) Level the top surface and smoothen it with a trowel

• CURING:

The test specimens are stored in moist air for 24hours and after this period the

specimens are marked and removed from the molds and kept submerged in clear fresh

water until taken out prior to test.

• PRECAUTIONS:

The water for curing should be tested every 7days and the temperature of water must

be at 27±2oC.

• PROCEDURE:

(I) Remove the specimen from water after specified curing time and wipe out excess

water from the surface.

(II) Take the dimension of the specimen to the nearest 0.2m

(III) Clean the bearing surface of the testing machine

(IV) Place the specimen in the machine in such a manner that the load shall be applied

to the opposite sides of the cube cast.

(V) Align the specimen centrally on the base plate of the machine.

(VI) Rotate the movable portion gently by hand so that it touches the top surface of

the specimen.

(VII) Apply the load gradually without shock and continuously at the rate of

140kg/cm2/minute till the specimen fails

46

(VIII) Record the maximum load and note any unusual features in the type of failure.

• NOTE:

Minimum three specimens should be tested at each selected age. If strength of any

specimen varies by more than 15 per cent of average strength, results of such

specimen should be rejected. Average of three specimens gives the crushing strength

of concrete.

• CALCULATIONS:

Size of the cube= 15cm x15cm x15cm

Area of the specimen (calculated from the mean size of the specimen)= 225cm2

Characteristic compressive strength (fck) at 7 days =

Expected maximum load =fck x Area x fs

Range to be selected is …………………..

Similar calculation should be done for 28 day compressive strength

Maximum load applied =……….tones = ………….N

Compressive strength = (Load in N/ Area in mm2)=……………N/mm2

• REPORT:

a) Identification mark

b) Date of test

c) Age of specimen

d) Curing conditions, including date of manufacture of specimen

e) Appearance of fractured faces of concrete and the type of fracture if they are

unusual

• RESULT:

Average compressive strength of the concrete cube = ………….N/ mm2 (at 7 days)

Average compressive strength of the concrete cube =………. N/mm2 (at 28 days)

Percentage strength of concrete at various ages:

The compressive strength of concrete increases with its age. Table shows the strength of

concrete at different ages in comparison with the strength at 28 days after casting.

Age: Strength %:

1 day 16%

3 days 40%

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7 days 65%

14 days 90%

28 days 99%

Compressive strength of different grades of concrete at 7 and 28 days

Grade of

Concrete

Minimum compressive strength

N/mm2 at 7 days

Specified characteristic compressive strength

(N/mm2) at 28 days

M15 10 15

M20 13.5 20

M25 17 25

M30 20 30

M35 23.5 35

M40 27 40

M45 30 45

CHECKING QUALITY OF FINE AGGREGATES AND BRICKS:

For checking the quality of fine aggregates, a field test was conducted in which the sand was

placed in a flask containing water. The sand was allowed to settle for some time and then

after few hours the reading of the silt or other impurity layer is taken. If that reading is less

than 5% of the total sand that is put in the flask, then we accept the sand but if it is more than

5% the sand is rejected. Bricks were sent to the college laboratory for testing and thereby

checking the quality of the bricks used at site.

48

TESTS ON CEMENT:

INITIAL AND FINAL SETTING TIME

We need to calculate the initial and final setting time as per IS: 4031 (Part 5) – 1988. To do

so we need Vicat apparatus conforming to IS: 5513 – 1976, Balance, whose permissible

variation at a load of 1000g should be +1.0g, Gauging trowel conforming to IS: 10086 –

1982.

• PROCEDURE:

i) Prepare a cement paste by gauging the cement with 0.85 times the water required to

give a paste of standard consistency.

ii) Start a stop-watch, the moment water is added to the cement.

iii) Fill the Vicat mould completely with the cement paste gauged as above, the mould

resting on a non-porous plate and smooth off the surface of the paste making it level

with the top of the mould. The cement block thus prepared in the mould is the test

block.

• INITIAL SETTING TIME:

Place the test block under the rod bearing the needle. Lower the needle gently in order

to make contact with the surface of the cement paste and release quickly, allowing it

to penetrate the test block. Repeat the procedure till the needle fails to pierce the test

block to a point 5.0 ± 0.5mm measured from the bottom of the mould.The time period

elapsing between the time, water is added to the cement and the time, the needle fails

to pierce the test block by 5.0 ± 0.5mm measured from the bottom of the mould, is the

initial setting time.

• FINAL SETTING TIME:

Replace the above needle by the one with an annular attachment. The cement should

be considered as finally set when, upon applying the needle gently to the surface of

the test block, the needle makes an impression therein, while the attachment fails to

do so. The period elapsing between the time, water is added to the cement and the

time, the needle makes an impression on the surface of the test block, while the

attachment fails to do so, is the final setting time.

49

CONSISTENCY TEST:

The basic aim is to find out the water content required to produce a cement paste of standard

consistency as specified by the IS: 4031 (Part 4) – 1988. The principle is that standard

consistency of cement is that consistency at which the Vicat plunger penetrates to a point 5-

7mm from the bottom of Vicat mould.

• APPARATUS: Vicat apparatus conforming to IS: 5513 – 1976, Balance, whose

permissible variation at a load of 1000g should be +1.0g, Gauging trowel conforming

to IS: 10086 – 1982.

• PROCEDURE:

i) Weigh approximately 400g of cement and mix it with a weighed quantity of water.

The time of gauging should be between 3 to 5 minutes.

ii) Fill the Vicat mould with paste and level it with a trowel.

iii) Lower the plunger gently till it touches the cement surface.

iv) Release the plunger allowing it to sink into the paste.

v) Note the reading on the gauge.

vi) Repeat the above procedure taking fresh samples of cement and different

quantities of water until the reading on the gauge is 5 to 7mm.

• REPORTING OF RESULTS:

Express the amount of water as a percentage of the weight of dry cement to the first

place of decimal.

50

TESTS ON AGGREGATES:

FINE AGGREGATES:

SIEVE ANALYSIS

Sieve analysis helps to determine the particle size distribution of the coarse and fine

aggregates. This is done by sieving the aggregates as per IS: 2386 (Part I) – 1963. In this we

use different sieves as standardized by the IS code and then pass aggregates through them and

thus collect different sized particles left over different sieves.

COARSE AGGREGATES:

AGGREGATE CRUSHING VALUE

This test helps to determine the aggregate crushing value of coarse aggregates as per IS: 2386

(Part IV) – 1963. The apparatus used is cylindrical measure and plunger, Compression testing

machine, IS Sieves of sizes – 12.5mm, 10mm and 2.36mm.

• PROCEDURE:

i) The aggregates passing through 12.5mm and retained on 10mm IS Sieve are oven-

dried at a temperature of 100 to 110oC for 3 to 4hrs.

ii) The cylinder of the apparatus is filled in 3 layers, each layer tamped with 25

strokes of a tamping rod.

iii) The weight of aggregates is measured (Weight ‘A’).

iv) The surface of the aggregates is then leveled and the plunger inserted. The

apparatus is then placed in the compression testing machine and loaded at a uniform

rate so as to achieve 40t load in 10 minutes. After this, the load is released.

v) The sample is then sieved through a 2.36mm IS Sieve and the fraction passing

through the sieve is weighed (Weight ‘B’).

vi) Two tests should be conducted.

• RESULT:

Aggregate crushing value = (B/A) x 100%.

51

2.8 REINFORCEMENT

Steel reinforcements are used, generally, in the form of bars of circular cross section in concrete structure. They are like a skeleton in human body. Plain concrete without steel or any other reinforcement is strong in compression but weak in tension. Steel is one of the best forms of reinforcements, to take care of those stresses and to strengthen concrete to bear all kinds of loads. Mild steel bars conforming to IS: 432 (Part I) and Cold-worked steel high strength deformed bars conforming to IS: 1786 (grade Fe 415 and grade Fe 500, where 415 and 500 indicate yield stresses 415 N/mm2 and 500 N/mm2 respectively) are commonly used. Grade Fe 415 is being used most commonly nowadays. This has limited the use of plain mild steel bars because of higher yield stress and bond strength resulting in saving of steel quantity. Some companies have brought thermo mechanically treated (TMT) and corrosion resistant steel (CRS) bars with added features. Bars range in diameter from 6 to 50 mm. Cold-worked steel high strength deformed bars start from 8 mm diameter. For general house constructions, bars of diameter 6 to 20 mm are used. Transverse reinforcements are very important. They not only take care of structural requirements but also help main reinforcements to remain in desired position. They play a very significant role while abrupt changes or reversal of stresses like earthquake etc. They should be closely spaced as per the drawing and properly tied to the main/longitudinal reinforcement

Terms used in Reinforcement

Bar-bending-schedule: Bar-bending-schedule is the schedule of reinforcement bars prepared in advance before cutting and bending of rebars. This schedule contains all details of size, shape and dimension of rebars to be cut.

Lap length: Lap length is the length overlap of bars tied to extend the reinforcement length.. Lap length about 50 times the diameter of the bar is considered safe. Laps of neighboring bar lengths should be staggered and should not be provided at one level/line. At one cross section, a maximum of 50% bars should be lapped. In case, required lap length is not available at junction because of space and other constraints, bars can be joined with couplers or welded (with correct choice of method of welding).

Anchorage Length: This is the additional length of steel of one structure required to be inserted in other at the junction. For example, main bars of beam in column at beam column junction, column bars in footing etc. The length requirement is similar to the lap length mentioned in previous question or as per the design instructions.

52

Reinforcement for the playground at the site:

Shear Reinforcements:

53

2.9 BRICKWORK, PLASTERING

AND FINISHING

BRICKWORK

Brickwork is masonry done with bricks and mortar and is generally used to build partition

walls. Every brickwork has a fine side, the side of the brickwork at which the mason actually

stands and builds the brickwork, and an unfine side or the opposite side. Proper measures

should be taken to ensure that the dimensions and the quality of the brickwork on the fine

sides are maintained accurately. At the site, all the external walls were of concrete and most

of the internal walls were made of bricks, and Fly ash bricks were used. English bond was

used and a ration of 1:4 (1 cement: 4 coarse sand) was used irrespective of whether the wall is

5 inches or 10 inches for convenience. Some temporary constructions were done (mainly for

safety purposes) which were made with a mix of 1:8 or 1:9. The reinforcement shall be 2 nos.

M.S. round bars or as indicated. The diameter of bars was 8mm. The first layer of

reinforcement was used at second course and then at every fourth course of brick work. The

bars were properly anchored at their ends where the portions and or where these walls join

with other walls. The in laid steel reinforcement was completely embedded in mortar.

Tower 3 Brickwork:

54

The bricks used at our site were modular bricks. Now bricks can be of two types, which are:

1) Traditional Bricks-The dimension if traditional bricks vary from 21 cm to 25cm in

length,10 to 13 cm in width and 7.5 cm in height in different parts of country .The commonly

adopted normal size of traditional brick is 23 * 11.5*7.5 cm with a view to achieve

uniformity in size of bricks all over country.

2) Modular Bricks- Indian standard institution has established a standard size of bricks such

a brick is known as a modular brick. The normal size of brick is taken as 20*10*10 cm

whereas its actual dimensions are 19*9*9 cm masonry with modular bricks workout to be

cheaper there is saving in the consumption of bricks, mortar and labour as compared with

masonry with traditional bricks.

STRENGTH OF BRICK MASONRY

The permissible compressive stress in brick masonry depends upon the following factors:

1. Type and strength of brick.

2. Mix of mortar.

3. Size and shape of masonry construction.

The strength of brick masonry depends upon the strength of bricks used in the masonry

construction. The strength of bricks depends upon the nature of soil used for making and the

method adopted for molding and burning of bricks .since the nature of soil varies from region

to region ,the average strength of bricks varies from as low as 30kg/sq cm to 150 kg /sq cm

the basic compressive stress are different crushing strength.

There are many checks that can be applied to see the quality of bricks used on the site.

Normally the bricks are tested for Compressive strength, water absorption, dimensional

Brickwork in Tower 3:

55

tolerances and efflorescence. However at small construction sites the quality of bricks can be

assessed based on following, which is prevalent in many sites.

• Visual check – Bricks should be well burnt and of uniform size and color.

• Striking of two bricks together should produce a metallic ringing sound.

• It should have surface so hard that can’t be scratched by the fingernails.

• A good brick should not break if dropped in standing position from one metre above ground

level.

• A good brick shouldn’t absorb moisture of more than 15-20% by weight, when soaked in

water

For example; a good brick of 2 kg shouldn’t weigh more than 2.3 to 2.4 kg if immersed in

water

for 24 hours.

PRECAUTIONS TO BE TAKEN IN BRICK MASONRY WORK

• Bricks should be soaked in water for adequate period so that the water penetrates to its full

thickness. Normally 6 to 8 hours of wetting is sufficient.

• A systematic bond must be maintained throughout the brickwork. Vertical joints shouldn’t

be

continuous but staggered.

• The joint thickness shouldn’t exceed 1 cm. It should be thoroughly filled with the cement

mortar 1:4 to 1:6 (Cement: Sand by volume)

• All bricks should be placed on their bed with frogs on top (depression on top of the brick for

providing bond with mortar).

• Thread, plumb bob and spirit level should be used for alignment, verticality and

horizontality of construction.

• Joints should be raked and properly finished with trowel or float, to provide good bond.

• A maximum of one metre wall height should be constructed in a day.

• Brickwork should be properly cured for at least 10 days.

56

PLASTERING

Sand-cement plaster is used extensively in building work as a decorative or protective

coating to concrete and masonry walls and concrete ceilings. We know that in general

plastering purposes we use a mix of 1:6 on the walls and 1:4 on the ceiling, however at the

site a mixture of 1:4 is applied throughout for convenience. The thickness of the plaster is

kept at 6-8 mm in the ceiling, 10-12 mm in the walls and 20-25 mm at the external surface.

Before plastering, a layer of cement slurry is applied on the surface for better bonding of the

plaster with the substrate. In various parts of the constructions, especially at the joints in

brickwork, during plastering chicken wire mesh is used to hold cement or plaster, thus

increasing the bonding strength between the plaster and the substrate, in a process known

as stuccoing. It is provided either horizontally or vertically, and in the case of brickwork, it is

provided after a vertical gap of 2-3 layers of bricks. Concrete reinforced with chicken

wire yields ferrocement, a versatile construction material. If the mesh is not provided

properly, then surface cracks will develop. Plaster has important requirements in the fresh

and hardened states. In the fresh state plaster must be workable, cohesive and plastic, and

have good water retention. The properties of fresh plaster depend on the materials used,

especially the sand, and on mix proportions. In the hardened state, plaster must be: strong

enough to hold paint and withstand local impact and abrasion; free of unsightly cracking;

well bonded to the substrate; have an acceptable surface texture; and have acceptable surface

accuracy (with reference to a plane or curved surface). The properties of hardened plaster

depend on the properties of the fresh plaster and the substrate, and on workmanship. For

accurate work, apply screed strips before the wall is plastered. These are narrow strips of

plaster along the perimeter of the wall, or at suitable intervals on the wall, that act as guides

for the striker board. Using a rectangular plasterer’s trowel, push plaster onto the wall or

ceiling using heavy pressure to compact the plaster and ensure full contact with the substrate.

The plaster should be slightly proud of the intended surface. Once the plaster starts to stiffen,

it should be struck off to a plane (or curved) surface using a light striker board or as it is

locally known as “funty”. Material removed in this way should be discarded. If plaster is to

be applied in more than one coat, the undercoat(s) should be scored with roughly parallel

lines about 20 mm apart and 5 mm deep. The purpose of scoring is two-fold; to provide a key

for the next coat and to distribute cracking so that it is less noticeable.

57

FINISHING

Concrete that will be visible, such as slab like driveway, highway or patios often need finishing. Concrete

slabs can be finished in many ways, depending on the intended service use. Options include various colors

and textures, such as exposed aggregate or a patterned stamped surface. Some surface may require only

strike off and screeding to proper contour and elevation, while for other surface a broomed,

floated, or troweled finish may be specified. In slab construction screeding or strike off is the process of cutting

off excess concrete to bring the top surface of the slab to proper grade. A straight edge is

moved acrossthe concrete with a sawing motion and advanced forward a short distance with each movement.

Bull floating eliminates high and low spots and embeds large aggregate particles immediately after strike

off. This look like a long handled straight edge pulled across the concrete. Joining is required to eliminate

unsightly random cracks. Construction joints are made with a groover or by inserting strips of plastic,

wood, metal, or performed joints material into the unhardened concrete. Saw cut joints can be made

after theconcrete is sufficiently hard or strong enough to prevent the reveling. Afterthe concrete has been jointe

d it should be floated with a wood or metal handfloat or with a finishing machine using float blades. This

embeds aggregateparticles just beneath the surface; removes slight imperfections, humps, and voids; and

compacts the mortar at the surface in preparation for addition finishing operations. Where a smooth, hard,

dense surface is desired, floating should be followed by steel troweling.

Troweling should not be done on aSurface that has not been floated; troweling after only bull floating is not an

adequate finish procedure. A slip resistant surface can be produced by brooming before the concrete

has thoroughly hardened but it should be sufficient hard to retain the scoring impression.

Finished Surface:

58

2.10 FOUNDATION: PILE WORKS

There are many reasons a geotechnical engineer would recommend a deep foundation over a

shallow foundation, but some of the common reasons are very large design loads, a poor soil

at shallow depth, or site constraints (like property lines). There are different terms used to

describe different types of deep foundations including the pile (which is analogous to a pole),

the pier (which is analogous to a column), drilled shafts, and caissons. Piles are generally

driven into the ground in situ; other deep foundations are typically put in place using

excavation and drilling. DMC piling is used at this site. In DMC, or Direct Mud Circulation

pile, water jet is let through the piling chisel which comes out from bottom with mud. In

DMC pile foundation, bentonite suspension is pumped into the bottom of the hole through the

drill rods and it overflows at the top of the casing. The mud pump should have the capacity to

maintain a velocity of 0.41 to 0.76 metres per second to float the cuttings.

EQUIMENTS USED AT THE SITE:

Equipment: Use:

Tripod Stand Used as a platform for supporting the weight

and maintaining the stability of the

equipments

Piling Winch Used to wind up or wind out or otherwise

adjust the "tension" of the cable

DMC Chisel Used for boring the soil for the pile

DMC Pipes Used to allow the water jet

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Bailor Used for driving the casing

Tremie Pipes Used for placing concrete below water level

Hopper Large sized storage tanks which discharges

concrete from the bottom

Pumps Used for circulating bentonite slurry

Chute Cart Transporting materials

SPECIFICATIONS OF PILES USED AT THE SITE:

Diameter of Pile: 500 mm

Clear Cover: 50 mm on all sides

Tremie Pipe Diameter: 200 mm

DMC Pipe Diameter: 150 mm

Specific Gravity of Bentonite: 1.1 g/cc

Grade of Concrete: M25

Cement Content: 400 kg/m3

Concrete Mix: (Cement : Water : Fine Aggregates: Coarse Aggregates)

1:2:1:1

METHOD FOR PILING:

• Excavate till the COL of pile.

• Predict the level of concrete inside the pile by driving rebar to touch the hard strata of

concrete.

• Excavate till the predicted level of pile till visibility of concrete

• Chip off loose concrete/ laitance from the top level of exposed concrete and ensure

the quality of concrete after chipping.

• Straighten the distorted vertical bars & tie the lateral ties/ helical to COL

• Fix the formwork of the required size up to the pile COL

• Apply the bonding agent (Nitobond EP) before pouring the concrete with the help

ofan extended brush.

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• Pour concrete of the same grade (M30)

• Strip the form work after 24 hrs

• Back fill around the piles in layers not exceeding 200mm up to COL and allow for

PCC

• FDT to be carried out as per relevant IS Code and Technical specification.

• Curing of concrete with approved water shall start after completion of Initial setting

time of concrete and in hot weather after 4 hours. Concrete will be cured for a

minimum period of seven days when OPC with high water cement ratio is used;

curing for minimum 10 days in hot weather or low water cement ratio is used. Curing

shall be done by continuous sprays or pond water or continuously saturated coverings

of sacking canvas, hessain or other absorbent material for the period of complete

hydration with a minimum of 7 days. Curing shall also be done by covering the

surface with an impermeable material such as Polyethylene, which shall be well

sealed and fastened.

Piling for Tower 7 at the site:

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2.11 SHUTTERING AND SCAFFOLDING

DEFINITION

The term ‘SHUTTERING’ or ‘FORMWORK’ includes all forms, moulds, sheeting,

shuttering planks, walrus, poles, posts, standards, leizers, V-Heads, struts, and structure, ties,

prights, walling steel rods, bolts, wedges, and all other temporary supports to the concrete

during the process of sheeting.

FORM WORK

Forms or moulds or shutters are the receptacles in which concrete is placed, so that it will

have the desired shape or outline when hardened. Once the concrete develops adequate

strength, the forms are removed. Forms are generally made of the materials like timber,

plywood, steel, etc.

Generally camber is provided in the formwork for horizontal members to counteract the

effect of deflection caused due to the weight of reinforcement and concrete placed over that.

A proper lubrication of shuttering plates is also done before the placement of reinforcement.

The oil film sandwiched between concrete and formwork surface not only helps in easy

removal of shuttering but also prevents loss of moisture from the concrete through absorption

and evaporation.

The steel form work was designed and constructed to the shapes, lines and dimensions shown

on the drawings. All forms were sufficiently water tight to prevent leakage of mortar. Forms

were so constructed as to be removable in sections. One side of the column forms were left

open and the open side filled in board by board successively as the concrete is placed and

compacted except when vibrators are used. A key was made at the end of each casting in

Shuttering in Tower 4 at site:

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concrete columns of appropriate size to give proper bonding to columns and walls as per

relevant IS Codes.

CLEANING AND TREATMENT OF FORMS

All rubbish, particularly chippings, shavings and saw dust, was removed from the interior of

the forms (steel) before the concrete is placed. The form work in contact with the concrete

was cleaned and thoroughly wetted or treated with an approved composition to prevent

adhesion between form work and concrete. Care was taken that such approved composition is

kept out of contact with the reinforcement.

]

DESIGN

The form-work should be designed and constructed such that the concrete can be properly

placed and thoroughly compacted to obtain the required shape, position, and levels subject

ERECTION OF FORMWORK

The following applies to all formwork:

a) Care should be taken that all formwork is set to plumb and true to line and level.

b) When reinforcement passes through the formwork care should be taken to ensure close

fitting joints against the steel bars so as to avoid loss of fines during the compaction of

concrete.

c) If formwork is held together by bolts or wires, these should be so fixed that no iron is

exposed on surface against which concrete is to be laid.

d) Provision is made in the shuttering for beams, columns and walls for a port hole of

convenient size so that all extraneous materials that may be collected could be removed just

prior to concreting.

e) Formwork is so arranged as to permit removal of forms without jarring the concrete.

Wedges, clamps, and bolts should be used where practicable instead of nails.

Forms made at the site:

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f) Surfaces of forms in contact with concrete are oiled with a mould oil of approved quality.

The use of oil, which darkens the surface of the concrete, is not allowed. Oiling is done

before reinforcement is placed and care taken that no oil comes in contact with the

reinforcement while it is placed in position. The formwork is kept thoroughly wet during

concreting and the whole time that it is left in place.

Immediately before concreting is commenced, the formwork is carefully examined to

ensure the following:

a) Removal of all dirt, shavings, sawdust and other refuse by brushing and washing.

b) The tightness of joint between panels of sheathing and between these and any hardened

core.

c) The correct location of tie bars bracing and spacers, and especially connections of bracing.

d) That all wedges are secured and firm in position.

e) That provision is made for traffic on formwork not to bear directly on reinforcement steel.

VERTICALITY OF THE STUCTURE

All the outer columns of the frame were checked for plumb by plumb-bob as the work

proceeds to upper floors. Internal columns were checked by taking measurements from outer

row of columns for their exact position. Jack were used to lift the supporting rods called

props.

Props in Tower 1 at site:

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STRIPPING TIME OR REMOVAL OF FORMWORK

Forms were not struck until the concrete has attained a strength at least twice the stress to

which the concrete may be subjected at the time of removal of form work. The strength

referred is that of concrete using the same cement and aggregates with the same proportions

and cured under conditions of temperature and moisture similar to those existing on the work.

Where so required, form work was left longer in normal circumstances

Form work was removed in such a manner as would not cause any shock or vibration that

would damage the concrete. Before removal of props, concrete surface was exposed to

ascertain that the concrete has sufficiently hardened. Where the shape of element is such that

form work has re-entrant angles, the form work was removed as soon as possible after the

concrete has set, to avoid shrinkage cracking occurring due to the restraint imposed. As a

guideline, with temperature above 20 degree following time limits should be followed:

Structural Component Age

Footings 1 day

Sides of beams, columns, lintels, wall 2 days

Underside of beams spanning less than 6m 14 days

Underside of beams spanning over 6m 21 days

Underside of slabs spanning less than 4m 7 days

Underside of slabs spanning more than 4m 14 days

Flat slab bottom 21 days

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2.12 GENERAL NOTES

The general notes specify the quantities and quantities of materials, the proportion of the

mortar, workmanship, the method of preparation and execution, and the methods of the

measurement. The company prepares the general notes of various items of work, and gets

them printed in the book from under the name of general notes. Some of the general notes are

given below related to Building Construction.

1. Earthwork in excavation in foundation:

• Excavation: Foundation trenches shall be dug out to the exact width of the foundation

concrete and the sides shall be vertical. If the soil is not good and does not permit

vertical sides, the sides should be sloped back or protected with timber shoring.

• Finish and Trench: The bottom of the foundation trenches shall be perfectly leveled

both longitudinally and transversally and the sides of the trench shall be dressed

perfectly vertical from bottom up to least thickness of lose concrete may be laid to the

exact width as per design. The bed of the trench shall be tightly watered and well

rammed. Soft or defective spots shall be dug out excess digging if done through

mistake shall be filled with concrete.

• Measurement: The measurement of the excavation shall be taken in cu m as for

rectangular trench, bottom width of concrete multiplied by the vertical depth of the

foundation from ground level and multiplied by the length of the trench.

2. Foundation: The foundation of the building should be so planned and the lay out of the

foundation should be on the ground should be correct in the measurement.

• Should not place the concrete in the foundation before checked by the Engineer-in

charge.

• If building has the basement more than two raft foundations should be provided.

• In the P.C.C. it should be in the ratio of 1:4:8 and 75 mm thick 75 mm projected

beyond raft foundation.

• The concrete provided in the raft foundation should be M-25 grade conforming to IS

456.

• The design and thickness of the raft foundation provided by the soil testing.

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3. Reinforcement Concrete Work:

• All reinforcement shall be of tested quality high yield strength deformed bars

conforming to IS 1786 shall be used as reinforcement steel.

• The lap length of bars shall be equal to K(splice factor) x diameter of small bar.

• Lapping of bars shall be suited staggered and in no case more than 50% bars shall be

lapped at any section.

• The chair to support the raft foundation bars can be provided at the distance of the one

meter.

• The length of the anchorage should be 300mm.

• The reinforcement should be provided as per the detailed drawing specification.

• The bars of the reinforcement should straight not be in the zigzag manner.

• Check the slump of the concrete when concrete is placing.

• Clean cover to the main reinforcement shall be as follows:

Structural element: Top: Bottom: Sides:

1. Footing/raft 50 50 50

2. Column dimension up to

230

- - 25

3. Column dimension up

above 230

- - 40

4. R.C.C. wall up to150

thick.

25 25 25

5. R.C.C. wall above150

thick.

40 40 40

6. Beams 25 25 25

7. Lintel up to 200 mm depth 15 15 15

8. Lintel above 200 mm

depth

25 25 40

9. Slab & chhaja 15 15 25

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4. Plastering:

• The joints of the brick work shall raked out to a depth of 12 mm and the surface of the

wall washed and clean and kept wet for the two days before plastering. The material

of mortar should be of standard specification.

• The thickness of the plastering shall be of 12mm to ensure uniform thickness of

plaster; patches of 15 cm shall be applied first at about 2 m apart to act as guide. First

mortar shall be dashed and pressed over the surface and then brought to a true smooth

and uniform surface by means of float and trowel.

• Wall plastering shall be started from top and worked down towards floor. Ceiling

plastering shall be completed before starting of wall plaster.

• All corner and edge shall be rounded. The plastered surface shall be kept wet for

10days the surface should be protected from rain, sun, frost, etc.

• For wall plastering 1:6 cement mortar and for ceiling plastering 1:4 cement mortar

with coarse sand is used.

5. 25 cm Cement Concrete floor:

• The cement concrete shall be of proportion 1:2:4 cement shall be fresh Portland

cement of standard specification. The coarse aggregate shall be hard and tough of

3cm gauge, well graded and free from dust, dirt, etc. the sand shall be coarse of 5

mm maximum size and down, well graded, clean and free from dust, direct and

organic matters.

• The floor shall be leveled and divided into panels or bays of maximums size or

1.2mx1.2m and the sides of the panels shall be bounded with teak wood battens 2.

cm thick and 5 cm wide or flat iron of same thickness and fixed with weak mortar, or

with nails or hooks. Required camber or slope should be given in floor for draining

wash water.

• Mixing of concrete shall be down by measuring with boxes to have the required

proportion as specified.

o First cement and sand mixed dry and the dry mix of cement and sand mixed

with ballast dry, and the mixed by adding water slowly and gradually to the

required quantity, and mixed thoroughly to have a uniform plastic mix.

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o Base: In ground floor the c.c. floor shall be laid on a 7.5cm base of weak

cement concrete as per standard specifications.

6. White Washing: Fresh white lime slaked at site of work should be mixed with sufficient

water to make a thin cream. It shall then be screened through a coarse cloth, and gum in

proportion of 100 gms of gums to 16 liters of wash shall be added. The surface should be dry

and thoroughly cleaned from dust and dirt. The wash shall be applied with Moonj or jute

brush, vertically and horizontally. And the wash kept stirred in container while using. Two or

three coats shall be applied as specified, and each coat shall perfectly dry before the

succeeding coat is applied over it. Dry before the succeeding coat shall be applied as

specified, and each coat shall be perfectly dry before the succeeding coatis applied as

specified, and each coat shall be perfectly dry before the succeeding coat is applied over it.

After finishing the surface shall be of uniform color. In old surface, the surface should be

cleaned and repaired with cement mortar where necessary and allowed to dry before white

wash is applied.

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20. CONCLUSION:

It was a wonderful learning experience at the site of Simplex Infrastructure Ltd.’s project

Silveroak Estate, for a month in Rajarhat. I gained a lot of insight regarding almost every

aspect of the construction site. I was given exposure in almost all the departments at the site,

and was elucidated about the various intricate details by the personals present on the site,

which helped me in increasing my knowledge about the basic & advanced techniques of

building construction. I learnt that as a Civil Engineer, one should possess good knowledge

about how the things are done practically at the construction site. Theoretical knowledge

alone is insufficient for a Civil Engineer, or as an Engineer as a whole. Besides, this training

program makes me realized the value of working together as a team and as a new experience

in working environment, which imposes challenges to us in every minute. I was exposed to

the various challenges which a civil engineer had to face during construction i.e. labour

problems, cost management, environmental challenges etc. The friendly welcome from all the

employees was really appreciative, sharing their experience and giving their piece of wisdom,

gained by them in their long line of work. The experience will surely help me in my future

and also in shaping my career further as a Civil Engineer.

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REFERENCES

The various books, codes and journals used as a reference for this report are:

• IS 456:2000

• IS 800:2007 • N.N. Basak (1994), Surveying and Levelling; Project Surveys: Project on Township;

pg 468-69 • M.S. Shetty, Concrete Technology, Types of Cement and their tests, pg 27-65 • Dr. B.C. Punmia, Ashok Kumar Jain, Arun Kumar Jain (1993), Building

Construction; Masonry-2: Brick Masonry, Plastering and Pointing, Form-work; pg 241-304, 595-609, 711-19

• B.A. Gilly, A. Touran, and T. Asai, "Quality Control Circles in Construction", ASCE Journal of Construction Engineering and Management, Vol. 113, No. 3, 1987, pg 432

• Hinze, Jimmie W., Construction Safety, Prentice-Hall; 1997. • Improving Construction Safety Performance, Report A-3, The Business Roundtable,

New York, January 1982.

The various websites used as a reference for this report are:

• www.simplexinfra.com • www.silveroakestate.com

• www.nkrealtors.com • www.en.wikipedia.org • www.google.co.in

• www.scribd.com • www.understandconstruction.com