EGINEERING SPECIFICATIONS

CIVIL AND STRUCTURE

The following grades -of concrete shall be used. Richer concrete grades may be used to suit the design and local conditions.

Grade M-25

Only where required by design considerations/

e.g.,

— Long span beams, with restricted sizes

— Pipe rack frames of large spans (Beams and columns only) subjected to heavy loads.

Tall buildings, heavily loaded technological structures, only where column sizes are restricted.

- Precast members element)

Grade M-20

(to suit type of structure/

CONCRETE GRADES

1.

2.

2. Grade- M-20

—Building and pipe rack foundations including pile caps for large pile groups.

— Equipment foundations subjected to static And dynamic loads.

— Suspended Slabs, beams and columns in superstructure. .

— Pipe rack frames (beams and columns)

— Water retaining structures

—Retaining walls

— Precast members (to suit type of structure/

element) _

Grade M-15

caps for small pipe groups Nominally reinforced foundations

Nominally loaded foundations Minor equipment foundations Slab on

grade subjected to heavy loads e.g., technological structures,

warehouses, workshops. Cable -trenches

SPECIFICATION FOR DESIGN & CONSTRUCTION OF CIVTL & STRUCTURAL WORKS

GENERAL

SCOPE

This specification gives the general requirement! for the design, material and construction of all civil and structural works, the scope of which la given separately.

The following are also part of work covered by this specification.

a) Placing in position and fixing of all items such as insert-plates, pipe sleeves, anchor bolts etc.

-b) -Provision -of foundations consistent -with the soil conditions at site. It shall be the contractor's responsibility to decide the type of foundations to be provided (including piling if required).

1.1.3 Contractor shall be responsible for the design and construction of all works, RCC, structural steel and other relevant civil structural works.

1.1.4 The contractor shall submit to the owner all the design data (i.e., standards, references and ; technical literature), calculations and drawings for sub-structure, Superstructure. and all other connected works for approval /review as par - attached list. . However, the approval of the drawings by the owner does not absolve the . contractor of his responsibilities regarding the soundness of the structure.

1.1.5 -: . -The contractor shall submit a list of drawing h e proposes to make along with a time—schedule ' for submission of these drawings for approval/ review, taking into account the interaction .

1. 1.1

1.1.1

1.1.2

with other engineering disciplines -and the overall project schedule. The contractor shall submit necessary number of prints - -for approval/review and final records.

All designs (including computer output) drawings and construction shall be done as per relevant Indian Standards and Structural Design Specifications using metric system and English language.

All design calculations and drawings shall be neat, clear and systematic and done/printed using durable approved quality paper.

All steel structures shall be fire proofed -ft as :per' Owner's requirements and fire insurance regulations. All concrete structures shall also have fire resistance as for steel structures and aggregate type and concrete covers to reinforcement bars shall be provided accordingly.

Obtaining statutory approval, if any, .shall be Contractor4s responsibility.

All drawings pertaining to civil—structural engineering shall be submitted separately. Also design/drawings for various units/ Structure shall be submitted under separate transmittals to enable proper recording and control of review/approval work.

Contractor shall submit progress reports of submittal/review of design/drawing work on approved format.

'Contractor shall ensure that detailed scope of t/work is furnished by him with bid,

1.1.6

1.1.7

1,1.8

1.1.9 1.1.10

1.1.11

1.1.12

In case of computer aided analysis/designs, shall relevant back-ups such as load etc. calculation, flow charts, computer data etc. shall be furnished. Computer outputs shall be in clear, easily understandable formats and shall be submitted in properly bound volumes.

All engineering standards proposed to be used for civil constructions shall be submitted in suitably bound volumes before starting submission of detailed designs and drawings.

DESIGN

The design shall be on the basis of structural design specifications enclosed herewith and shall conform to the relevant Indian Standard Codes.

All structures/part of structures in contact with water/liquid shall be designed as water retaining structures strictly -as per ISs3370 parts I -to IV.

Soil data to be used for the design of the foundations and structures shall be as per annexure.

CONSTRUCTION

The construction shall be done as per relevant Indian Standards.

Any payment \ clause in each of the above specifications shall not be applicable for work awarded on a lump sum basis.

All regulations and laws on construction safety, labour, sanitation and health, etc. AS far as they are applicable, shall be complied with by the -contractor.

1 . 3 . 2

1.1.13

1.1.14

1.2

1.2.1

1.2.2

1.2.3

1.3

1.3.1

.5

1.3.3

MATERIALS

Material Specifications for civil -and structural work shall conform to the .relevant Indian Standard.

The contractor shall procure and provide the whole of the materials required for the construction including steel, cement, and other building materials, tools, tackles, construction plant and equipment for the completion and maintenance of works, and shall make his own arrangement for procuring such materials and for the transport thereof. Contractor shall use materials which bear The ISI stamp and/or equivalent which are supplied by reputed suppliers an DGS&D list,

DRAWINGS

Detailed working drawings, on the basis of which actual execution of work is to proceed will be furnished on an agreed time schedule by the contractor to owner for approval/review.

1.4

1.4.1

1.4.2

1.5

Concrete Structures

— General purpose

— Raft foundations

— Machine foundations

— Water retaining structure

— Piling

Steel Structures

DESIGN SPECIFICATIONS

Scope

The design criteria given herein establish -the minimum basic requirements £or design of reinforced concrete structures and structural steel works.

2.0

2.1

2-

Structural steel .in general building construction

Steel tubes In general building construction

Metal arc welding for

general building construction.

2.2.3

All other relevant codes specified or referred in the above codes and wherever the reference is made, shall be With latest revisions.

Any exceptions or additions to "these speci-

fications, Including any mandatory rules or

regulations which are to apply, shall be

indicated on the design

drawings/calculations.

DESIGN DATA

Meteorological Data

Temperature (Refer Design Criteria)

Rainfall (Refer Design Criteria)

Wind

Basic wind pressure - as per IS:875.

Approved shape factors to be considered.

Seismic

Zone III as defined in IS:1893.

Importance factor as defined in IS: 1893 shall be as follows:

— Pipe Racks : 1.5

— Equipment supporting structures : 1.5

— Compressor houses : 1.5

— Equipment foundations j As for equipment design,

Co-efficient of Friction

l 0.5

: 0.3

2.2.4

2.3.

2.4

2.4.1

2.4.

2

2.4.

3

2.4.

4

2.4.5

2.5 Steel on

concrete

Steel on steel

Concrete on soil

DESIGN CRITERIA

Loads j IS:875 and Annexure—1 of these -specifications.

Load cases and their combinations at Annexure 2.

Design basis for pipe racks at Annexure 3.

MINIMUM'HEIGHTS OF PLINTH/PEDESTALS

The minimum heights of plinth/pedestals above HPP/finished grade/floor level shall be:

300 mm above nearest road or pavement level.

Pedestals for struc-tural columns

— Open area

— Covered area

All equipment supporting foundations/pedestals:

- Open area - Covered area . - Stair Pedestals - Ladder Pedestals

As required but £ 300 mm As required but <{ 150 mm 150 mm 150 mm

Equipments supported As required but ••£ 150 mm on structures above slab/grating.

GROUTING

As required but •£ 25 mm

As required but «f 25 mm

non shrink grout shall be used.

FOUNDATIONS

The foundation type and its depth shall be decided by the contractor as per clause 2.7. Minimum factor of safety against overturning of foundations shall be 2 and against sliding shall be 1.5.

2.6

2.6.1

2.6.2

2.6.3 SOIL DATA

2.7

2.8.6

Building plinth

300 mm

150 mm

2.8.7

For structural

columns

For equipment

2.8.8

LEAN CONCRETE Lean concrete blinding layer of mix

1:4:8 shall be provided under : floor slabs and

foundations, However, for water retaining

structures mix shall be 1:3:6.

Minimum thickness of lean concrete layer shall be 75 mm_ and .shall extend 50 mm beyond the foundation edge. However, for _water retaining structures thickness shall be 1OO mm and shall extend 75 mm beyond the "foundation edge.

Lean concrete of MIX 1:4:8 shall be used as filler. material wherever loose sub grade exists, where the levels are to be maintained on newly filled up excavations, by removing the loose fill.

MATERIAL

CONCRETE

Grades of concrete to be used for different structures and foundations shall be as per Annexure 4. Other concrete grades shall be used to suit the design and local conditions. Different grades of concrete shall not be used in the came structure. Concrete grades shall be specified in 'the construction drawings.

REINFORCING BARS

Reinforcing .bars shall be cold/hot rolled

high yield deformed bars conforming .to IS:1786/

1139.

CEMENT

Ordinary Portland cement conforming to IS 269 shall be used for concrete structures.

2.8.9 2.8.9.1

2.8.9.2

2.8.9.3

'

2.8.10

2.8.10.1

2.8.10.2.

2.6.10.3

2 . 8 . 1 1 CONCRETE CONSTRUCTION AND INSPECTION

2.8.11.1 GENERAL

Specifications for construction and inspection of concrete shall be in accordance with equivalent IS std

DRAWINGS

Detailed working drawings shall be prepared and furnished by the contractor. Each drawing should carry adequate construction details, and indicate the diameter wise.requirement of reinforcement and grade wise quantity of concrete. The working drawing should be supplemented by Bar-Bending Schedules.

STEEL STRUCTURES

This specification covers the requirements governing the design, fabrication and erection of structural steel for structures, platforms, buildings, pipe racks and other works in steel.

CODES AND STANDARDS

As per annexure

DESIGN

GENERAL

All designs and details eh all be In accordance with IS:8OO and other relevant codes.

DESIGN -CRITERIA

As per clause 2.6 of these specifications.

ALLOWABLE STRESSES

The allowable stresses shall be as per IS:800 and relevant IS codes.

2.8.12

2.9

2.9.1

2.9.2

2.9.3

2.9.3.U

2.9.3.2

2.9.3.3

2.9.3.4

MINIMUM THICKNESS OF STEEL MEMBERS

The minimum thickness of various components of a structure shall be:

Trusses, purlins, girts and bracing Columns, beams _

Gussets

Stiffeners - Base Plates

The minimum thickness of rolled shapes for the above purpose shall be mean flange thickness, regardless of web thickness. -Metal exposed to marked corrosive. action shall be increased in thickness or otherwise protected against corrosion, using due engineering Judgment in each instance.

SLENDERNESS AND DEPTH RATIOS

The slenderness ratio of main members in tension or compression shall be in accordance with IS:800,

For other structural elements the following limiting ratios of depth to span shall be used.

— Trusses

— Rolled beams and girders for ordinary floors and rafters

— Supporting floor beams for Vibrating machinery

— Roof purlins & girts

— Gable columns

— Gantry girders (Rolled sections) —

Gantry girders (Built up)

6 mm

8 mm 8 mm 8 mm

10 mm

2.9.3.5

1/10

1/24

1/15

1/45

1/3.0

1/15

1/12

CONNECTIONS

All connections shall be welded as far as

possible.

Field connections shall be made with black bolts for ladders, handrail posts, stair stringers, removable members, and floor plates, platforms framing members 200 mm (8

M) and under in size, "purlins, -girts and

minor pipe support members that require -not more than three bolts per connection.

The minimum size of bolts shall be 16 mm unless limited by the size of the connected parts.

2.9.3.6

fti

MATERIAL

Unless otherwise specified, steel for hot trolled structural .shapes and plates shall conform to IS 1226/2062.

Steel tubes for structural purpose shall conform to IS:1161.

High strength bolts shall conform to IS:3757.

Bolts shall conform to IS;1367,

FABRICATION ERECTION AND_INSPECTION

The fabrication, erection and inspection of• steel structures shall be in accordance with GNFC Construction Specifications.

FABRICATION

Splices shall not be located closer than one meter. No splice in cantilevered beams shall be located closer to the support than one half the length. no splice shall be made in the middle fourth or in one eighth of the Span near support..

DRAWINGS

Detailed Working drawings shall be prepared and

furnished by the contractor. Each drawing

should carry adequate construction details and

be supplemented by fabrication and erection

drawings and section vise MTO.

ERECTION

Bolt holes for field connections shall be with the tolerances net forth In IS:800.

Welding shall be done in -accordance with IS823

Any erected section of a structure shall be self supporting to any external force likely to be

2.9.4

2.9.6

2.9.5

2.9.5.1

2.9.5.2

2.9.7

exerted -while erection is in progress. Any temporary bracing added to the structure for self support and alignment shall be designed to withstand all conditions of loading.

PAINTING, GALVANIZING; FIREPROOFINGS

All fabricated structural steel, unless galvanized shall receive a shot ;coat of primer, and painted.

-

Steel which is to be fireproofed (marked F.P. on design drawings) shall -be fabricated unpainted, and shall be given a coat of cement wash before encasement in concrete.

BUILDING CLASSIFICATION

Building shall be classified according

to the type of construction and material inputs.

BUILDING TYPES

TYIE A R.C.C. FRAME STRUCTURES

— Ground floor in concrete over hard

core/send.

- Rest of the floors in reinforced

concrete.

" Floor finish with mosaic/resilient tiles of

Kota stone etc. as required, (for office

building and control room) .

- Floor finish with I.F.S ./Ironite etc. as

required. (for pump house, compressor house, sub stations) .

— Side cladding in brick masonry plastered, or

pointed/A.C. sheets.

_- Interior wall (if any) in brick masonry,

- False ceiling where required in wood on/ aluminum frame work with Nova teak board or equivalent,

— Roof finish with water proofing and thermal

insulation as per required. -

- Doors of aluminum/steel/wood as required.

2.9.8

2.9.8.1

2.9.8.2

3.0

3.1 3.2

• Windows and ventilators of aluminum/steel/wood

framing with suitable glazing.

— Toughened glass for glazing of doors with or

without glazing- as required (for office

building)

TYPE B BUILDINGS WITH LOAD BEARING WALL5

Similar to type 'A' excepting for walls

which shall be load bearing type.

TYPE C R.C.C.COLUMNS WITH STEEL ROOF

-- RCC Columns and beams.

— Ground floor in concrete over hard core/sand.

-Floor. finish with I. P. S. /Ironite, as required.

— Side cladding in brick masonry, plastered or pointed A/C sheets.

— Interior walls(if any) in brick masonry.

— Roof covering An A.C. sheets/concrete over steel roof.

— Exterior doors/windows of steel as required.

— Steel rolling shutters as required.

— Interior doors of steel/wood as required.

TYPE D: STRUCTURAL STEEL COLUMNS WITH STEEL ROOF.

Similar to type C excepting for columns and beams which –shall be of. structural steel.

TYPE E: BRICK MASONRY WALLS AND PIERS WITH STEEL ROOF

Similar to type C excepting for columns and beams which shall be of structural steel.

LIST CF BUILDINGS AND THEIR TYPES

Buildings - --• Type

Compressor House •-

Pump House

3.4

3.5

3.6

3.7

Type A/C/D

REQUIREMENTS OF MINIMUM DESIGN LOADS IN BUILDINGS AND OTHER STRUCTURES

SCOPE

These requirements are intended to govern assumptions for dead, live and other loads in the design of buildings and other structures. The loads specified herein are the minimum suitable for use with stresses and load factors recommended in current design specifications for concrete, steel and any other structural materials used in buildings.

DEFINITIONS

Dead Load: The weight of all permanent construction including walls, floors, roofs, partitions, stairway and fixed service equipment and other equipment excluding their contents.

Live Load: The weight superimposed by the use and occupancy of the building or other structure, not including the wind load, earthquake load or dead load.

DEAD:LOADS

•Weights of specific materials and constructions. In estimating dead loads for purpose of design, the actual weights of materials and construction shall be used. By construction it is meant type of construction, e.g., walls, partitions, floor finish, etc.

Weight of fixed Service Equipment: In .estimating dead loads for purposes of design, the weight of

•fixed service equipment such as heating ventilating

-And air conditioning -systems shall be included wherever it is carried by the structural members.

Weight of 'Process Equipments: In estimating loads '-for purpose of design, the empty weight of the equipment including all fixtures and attached

-piping but excluding contents shall be considered.

Annexure—1

1 .2 ,

1 .1 ,

1.3 ,

^

<P

Provision for Parturitions: In office building or other similar buildings, where parturitions might be subject to erection or arrangement, provision for partition Weight shall be made by considering additional load of 100 kg/m2 whether or not partition are shown on the plans unless the specified live load -exceeds JOO kg/m2 .

LIVE LOADS

Live Loads on Floors

Live loads on floors of various types of buildings and other structures: Live loads on floors shall comprise of a]1 loads other than dead loads. The minimum live loads on floor for different uses shall be as given in Table—I. The loads specified in Table-I are uniformly distributed static loads ±n kg/m2 on plan area and provide for normal effects of impact and acceleration, but do not take into consideration special concentrated loads and other 'loads.

Process Equipment: In estimating live loads for purpose of design, the contents of the equipment shall be considered.

Live Loads on Roofs

Live loads on various types of Roofs: Flat roofs, sloping roofs and curved roofs shall be designed for live Loads as given in Table II, of IS 1875.

Impact and Vibrations — In accordance with IS 875

WIND LOADS - In accordance with IS-875.

SEISMIC LOADS - In accordance with IS:1893. COMBINATION OF LOADS

Generally combination of loads shall be as stated herein.

Combining Loads — Except when stated otherwise, all. loads listed herein shall be considered to act in the following combinations,

1.4.

1.4.1

.

1.4.2,

1.5.

produce the most unfavorable effects in buildings, foundations or structural members concerned. The most unfavorable effect may occur when one or more of the contributing load are acting.

D=Dead load consisting of

the weight of the member itself the weight of all materials of construction incorporated into the building to be permanently supported by the member, including built in partitions.

L=Loads due to intended use and occupancy (including loads due to movable partitions, traveling cranes , earth and hydrostatic pressure; horizontal components of static or inertial forces.

W=Wind Load

S=Seismic Load

T= Loads, forces and effects due to contraction

or expansion resulting from temperature changes, shrinkage, creep in component materials, movement due to differential settlement or combinations thereof.

NOTES: . Live load to be considered shall be partial or full whichever causes the most critical condition or whichever is most likely to occur in combination with the specified loading combination.

D+L+(WorS)+T

D D + L

D+(WorS) D+T D+L+(WorS) D+L+T D+T+(WorS)

(1)

(2)

(3) (4) (5)

(6)

(7)

(8)

Where

a)

b)

In ordinary buildings/structures, effects due to temperature fluctuations shrinkage and creep can be .ignored in the design calculations and as such load combinations 4,6,7,8 need not be considered. However, in special structures and at such locations where temperature fluctuations are large, such combinations shall be considered

Check for case where erection loads are likely to take place shall be made for D+L (such part as would be imposed during period of erection) WorS + Erection load.

Dead Load Counteracting Live Load —;When loads other than dead counteract live loads in a structural member or Joint, special care shall be exercised by the designer to ensure adequate safety for possible stress reversals.

1.6 Soil and Hydrostatic Pressure

Pressure on basement walls — In design of basement walls and similar approximately vertical structures below grade, provision shall be made for the lateral pressure of adjacent soil. Due allowance shall be made for possible surcharge from fixed or moving loads. When a portion or whole of the adjacent .soil is below a free water surface, computations shall be based on the weights of the soil diminished by buoyancy (submerged weight of the soil) plus full hydrostatic pressure.

Uplift on Floors — In .the design of basement floors •- and similar approximately horizontal constructions below grade, -the upward pressure of water, if any shall be taken as the full hydrostatic pressure applied over the entire area. The hydrostatic

head shall be measured from the underside of the

construction. Factor of safety against uplift shall be 1.2. For purpose of calculating downward load due to over burden, the weight .for the same shall be calculated for -volume over projected plan area. only. In other words volume' of overburden beyond '-projected plan area shall not be considered.

1.7 Reduction in Floor Live Loads

Reduction in floor live loads for design of .supporting members e.g., beams, columns, walls_, their supports and foundations shall be in accordance with relevant clauses of IS1875.

TABLE I LIVE LOADS OF FLOORS

S.No. Occupancy or use (Types of Floors)

Process Buildings (Both open type and enclosed type structures)

Operating Area: Maintenance

Area:

Metallurgical Plants Chemical Plants

Compressor House/T.G. House

Operating Area 750

Maintenance Area - 750

Service Platforms

On Vessels and Towers 300

Isolated Platforms (for 250 valve operation)

Gross Overs 200

Access Walkways 250

Substations

Panel Floor 1000

Stairs 300

Office Buildings

Offices. • : _ • - - • _ - 300

Lobbies . •/ • 500

Stairs & Exit ways ' 500

6.0 Warehouse &Workshops

Light ^ v 500

Medium 750

Heavy 1000

Or more as per actual

Loading conditions.

Or more as per actual

Loading conditions.

Or more as per actual

Loading conditions.

Includes panel loads

Files and computer rack

Require heavier loads

Based on anticipated

Occupancy.

Check for wheel load

Where applicable.

Remarks Live Load Kg/m2

1.0

1.1

1.2

6.1

6.2

6.3

500

750

500

Note: 1) For live loads on floors other than those mentioned above refer to Table I of IS:875.

2) Stair cases (Plan area)

- For Sr, No. 1.0 & 2.0 500 Kg/m2 for Treads 250 kg/m for Stringers.

250 kg/m2 for Treads and Stringers

2 300 kg/m2 for Treads ..and Stringers

2

500 kg/m2 for Treads

and Stringers

- For 3.0

- For 4.0

- For 5.0 & 6.0

LOAD CASES AND THEIR COMBINATIONS FOR

DESIGN OF STRUCTURES AND FOUNDATIONS

STACKS, TOWERS AND VERTICAL VESSELS

CASES — Dead Load (DL1) - Weight of equipment excluding fire proofing, piping, all loose materials, insulating, platforms supported from the equipment — Empty Weight (1)

- Dead Load (D.L2) - Weight of equipment including fire proofing, piping, all inter- nals, insulating, platforms supported from the equipment and weight of water - Test Weight (2)

- Dead Load (D.L3) - As (2) above but includes

- weight of liquid contents instead of

water -Operating weight (3)

- Erection Loads (E.L) - Temporary loads

and forces caused by erection (4)

- Live Load (L.L.) - On Platforms (5)

- Thermal load (T.L.) - where applicable (6)

- Pressure Load (P.L) - where applicable

and resulting from use-of expansion joints (7)

- Wind Load (W.L1) - 25% of wind load (8)

- Hind load (W.L2) -100% of wind load (9)

- Seismic Load (S-.L) ' (10)

NOTES - When piping weight is not indicated separately or included in the weight of the equipment, the same shall be considered to be minimum 10—15% of the operating weight of the equipment or more as per actual piping arrangement,

- To allow for surface area of piping, platforms and

other attachments fixed to the equipment, increase surface area exposed to the wind by e minimum 20% or more as per actual arrangement.

-—For first two platforms consider 50% L.L on each platform. For rest of the platforms consider 25% L.L on each platform.

Annexure—2

COMBINATIONS;

(1)

(2)

(3)

(4)

(5)

(5)

ERECTION (I)

TESTING (II)

OPERATING (III)

(9) or (10)

(8)

(6) (7)

(9) or (10)

EXCHANGERS AND HORIZONTAL-VESSELS

CASES — Dead Load (D.L1) — Weight of equipment when empty i.e.. Dry

— Dead Load (D.L2) - Weight of equip.when full i,e., Wet

- Temperature Load (T.L.)-mue x (D.L2) shared equality by all supports and acting in

longitudinal direction

— Bundle Pull

- Wind Load (W.L1) in longitudinal direction (5)

— Wind Load (w.L2) in transverse direction (6)

- Seismic Load (S.L) (7)

Allow for piping weight by adding 10% of equipment empty weight or more -as per accruals.

— Value of coefficient of friction (mue) to be taken as 0.1 with provision of Teflon pads and 0.25 when sliding steel plates ere provided.

— Bundle pull = 50-Kg per centimeter of exchanger shell diameter or 0.86 of the bundle weight, whichever is more (0,86 =Impact factor x coefficient of friction =1,5 x 0.57)

— Besides calculating wind load on equipment, calculate wind load on pedestals or piers.

(1) + (5) or {6)

(2) + (5) or (6)

(2) + {3 } + { ( 5 ) or ( 6 ) } or (7)

(2 ) + (7)

(1)

(2)

(3)

(4)

NOTES

COMBINATIONS

I.

II.

III

IV

IV.

im.—

r.M

th

»f

to t

h.-

frorr

ow

«r.

: • OPEN FRAME TYPE STRUCTURES SUPPORTING EQUIPMENT

C •-

»

-

•

> OT

3

CASESi • - Dead Load (DL1) — Weight of structures

V

C o •B —

equipment and piping without contents

(1)

• 0

*

£

a

^

L

=

c

— Dead. Load (D,L2) - As (1) above but

•

;

including contents at testing

(2) i

>

"

o

I

i

— Dead Load (D.L.3) - As (1) above but

v

_ ft O C a

o

including contents during operation

(3) o

S

g c

~

z

- Live Load (L.L1) - 50%

(4)

o

I

""T t

- Live Load (L.L2) - 100%

(5)

- Thermal Load (TL.) where applicable

- Pressure Load (P.L) where applicable

(6)

(7)

e:

»

•

£

= V

- Wind Load (W .L I) - 25%

(8). I

T

'

5

-

c

>

a

- Wind Load (W.L2) - 100%

(9) =

c

-

•

— Seismic Load (s.L)

(10)

5

-

?

^

\

COMBINATIONS

5

t

E = ~ « 0-C

ERECTION (I) (1) + (9) Or (10)

5

= u

: TESTING (II) (2) + (4) + .(8) -

C

a

5

S ^

*

*

OPERATING (III) (3) + (5) - + (6) + (7)+ (9) or (10)

NOTES - Every portion of "the structure shall be designed to resist the effects of the combinations stated above.

— In designing a structural member subjected to several maintenance loads, consideration shall be limited to two crane or trolley loads acting simultaneously and to one bundle pulling load.

— In designing open frame type structures

maintenance loads shall not be combined with

Wind or seismic loads.

— Where a common structure supports two or more items of equipment, variable effects such -as Weight of contents, end thermal loads shall be based on compatible conditions for loading combinations.

Truss Type Construction

D.L + L.L On Roof (100%)

Portal Type Construction

D.L + L.L on roof (100%) - Max, Crane Load + W.L.

(II) D.L + W.L D.L + W.L

LOAD COMBINATION FOR DESIGN OF ROOF LEG

D.L + L.L +. Surge

D.L + L.L + Surge + W.L. (50%)

D.L + L.L (50%) + Surge (50%) + W.L

LOAD COMBINATION FOR DESIGN OF CRANE GIRDER

(I) One crane loaded + surge .

(II) One crane loaded + surge + one crane unloaded.

(Ill) 'Two cranes fully loaded + surge (from heavier crane only) - No vertical impact to the considered.

LOAD COMBINATION FOR DESIGN OF COLUMN (OUTER LEG/CRANE LEG) AND FQUNDATIPN

(I) D.L + L.L (*) + surge

**(!!) D.L + L.L (*) + surge + W.L (50%)

**(III) D.L + W.L' (100%)

Notes

- Crane girders and supporting frame work shall be designed to carry the maximum wheel loads with wheel spacing as per the crane manufacturer.

CRANE BAYS

LOAD COMBINATION FOR ROOF DESIGN

(I)

(I)

**(II)

** (III)

— For designs prepared based on assumed loads and spacing, the design shall be reviewed for actual loads and spacing and if required corrective action taken.

— Vertical impact, horizontal surge and longitudinal tractive force shall be as per IS:875.

— Unless otherwise stated crane loads are position of wheel loads giving maximum design load and include vertical impact.

* Includes maximum crane load with vertical impact.

** Permissible stresses can be increased as per ISi800 for load combinations marked thus (**) provided contribution of wind load is more than the allowable increase in permissible stresses.

The above combinations are for one bay structures. For multi-bay structures, check shall be made for the following loading combinations.

(I) One crane in each aisle, with maximum wheel loads (including

specified vertical impact) and 50% combined surge and traction

from each crane.

(II) Maximum of two cranes in one aisle and one or two cranes in an adjacent aisle with maximum wheel loads, with full surge of the heaviest crane. No vertical impact or traction force shall be taken.

DESIGN BASIS FOR PIPE RACKS

LAYOUT AND GEOMETRY (Dimensions in mm) .

Spans (Transverse — Columns centre to centre)

Preferred 3000, 4500, 6000, 7500, '8000,/9000,

10,000

Acceptable; 1000 to 1500 increments above 3000.

longitudinal Bays (Main Transverse Bents -

Centre to centre)

Preferred 6000, 7000, 8OOO

Acceptable multiples of 500 or as required by spacing.

Keeping in mind compactness of racks, space availability and clearance for piping, bracing is generally limited to selected longitudinal bents located strategically approximately every 36 metres plus or minus 6 .metres where bracing limits minimum restriction to traffic etc. Generally bracings

shall not be permitted in transverse direction. However, if permitted as per layout, the bracings with minimum restriction to traffic can be provided.

Intermediate Supports

For -small lines, (depending upon piping requirements) intermediate supports shall be introduced. For transverse bents at 7500 centre and above, there

shall be two intermediate supports. Large diameter pipes shall be considered to span between main so that only -smaller lines throw light loading on intermediate supports.

Longitudinal Beams

Longitudinal beams shall be provided between the bents. Their function shall be to tie up main bents, provide supports for .intermediate supports and to distribute forces due to pipe anchors which cannot be generally located at an early stage. This way longitudinal Forces are ultimately resisted by the braced bays which need not necessarily be located directly below the pipe anchor.

1.0

1.1

1.2

1.3.

1.4

Annexure-3

1.5

DESIGN LOADING •

Piping Vertical Loads .••

Vertical loads are due to 'the weight of piping/ insulation, valves etc. Generally /these are determined or estimated as per job requirements. However, broadly, piping could be classified as light/ medium or heavy. The uniform load on the beams shall be calculated by multiplying the respective piping load per square meter with its area of command i.e., area supported by the beam.

Main Beams

The load categories and loads are;

S.No. Load Category Piping Load

Equivalent Pipe size and Spacing (Pipe filled with water/ no insu-lation)________

6" dia 40 @ 250 mm. centre to centre

8" dia Sch. @ 38 mm centre to centre

. 10" ,0 Sch.,20 @ 300 mm centre to centre

2.1.1.2 BL PIPE RACKS

For pipe racks under respective load categories —carrying pipes of sizes larger than the ones

indicated -above, additional point loads shall have to be considered over and above the respective uniformly distributed loads. ..

2.1.2 Intermediate Beams

Design for a uniform load intensity equal to 25% of the uniform .load on the main beams for the respective pipe rack load category. Where inter-mediate beams are provided, total vertical load .on main beams on account of uniformly .distributed load shall be reduced by 10%.

R£Y.

2.0

2.1.1

2.1.1.1

LIGHT 150 Kg/m2

200 Kg/m2 1.1 MEDIUM .

300 Kg/m2 Ill HEAVY

2,1,3 Longitudinal Beams

Design for uniform load intensity equal to 25% of the -uniform load intensity on main beams for the respective pipe rack load category plus point loads from intermediate beams. .Also check shall be made for 8" and above diameter/more number of pipes being supported on such longitudinal beams.

2-2 Piping Horizontal Loads

2.2.1 frictional Force Parallel to the Pipe

2.2il.l Main and Intermediate Beams

These shall be designed for horizontal force equal to 10% of the corresponding total vertical load and considered as uniformly distributed over the whole span of the beam.

2.2,1,2 Longitudinal Beams

These shall be designed for axial compression based on fractional force parallel to the pipes acting on main intermediate beams Simultaneously with vertical loads.

2,2.2 Anchor Force in Longitudinal Direction

2.2,2,1 .Main Beams

These shall be designed for anchor forces as per piping layout,

2.2,2*2 Longitudinal Beams

The transfer of- anchor forces will be through longitudinal beams to the braced bays. These beams shall be designed for axial compression load corresponding .to anchor force over and above the frictional force acting simultaneously with vertical piping load. •

2.2.3 Anchor Force in Transverse Direction

The main beams of the anchor bays shall be designed

for -anchor forces as given -in piping layout. These will be in addition to wind load acting transversely.

Wind Loads

Basic Wind pressure shall be as per provisions of IS B75

The projected area for calculating transverse wind load shall be product of spacing between the two adjacent bents and projected height This is based on span of pipe rack, probable depth of longitudinal beam and probable maximum. size of the pipe.

Generally -wind in longitudinal direction -shall not govern, however, in specific Cases -where applicable shall be checked if required.

Seismic Loads

Generally wind loads will be governing. But for plants located in high seismic prone area, seismic forces -may govern. In such cases, check for seismic forces shall be made. The seismic forces shall be calculated as per IS 1893.

Seismic Coefficient

The basic horizontal seismic coefficient shall be as per IS l893. .

Importance Factor

The importance factor for pipe racks in ISBL areas be 1,5

seismic Force

In Transverse Direction

Calculate the total' lateral force at each tier, based, on -.the total dead load at the level under consideration. This force shall be considered as external concentrated load at each level in trans-verse direction.

2.3

2.3.2

2.3.3 2.4

2.4.2

2.4.3

2.4.4

2.4.4.1

In Longitudinal Direction

This shall be calculated at each tier based on the beam reactions at the level under consideration. This force shall be considered as -external. concentrated load at each level in longitudinal direction. The transfer of these forces will be through longitudinal beams to the braced bays.

The above forces are over and above the anchor forces.

Loading Combinations

Case

I

Max.

D.L.

only

Case

II

Max.

D.L.

+ W.L

Case

III

.Min.

D.L.

+ W.L

Case

IV

.Max.

D.L.

+ S.L

Case

V

Max.

D.L.

+ T.L

Case

VI

Special loading

Lal lo;

= ding,

Dead load/ W.L. = Wind Load Seismic load, T.L. = Thermal load.

Where the total pipe rack is in structural steel it shall be designed as a portal fixed at base. However, in longitudinal direction, the column shall. be designed as fixed or hinged at base as per stability requirements.

Moment connections .shall be welded.

Pipes shall be considered to provide full lateral restraint to the beams. Effective length in longitudinal direction for 'T* support shall be 1.5 L -where L is height of the support.

Limiting deflection shall be 25 mm. maximum vertical at any level.

The transverse beam of the main bent which carry considerable thrust from pipe anchors shall be checked and investigated for lateral stability and if heed be stiffened or braced.

2.4.4.2

2.4.4.3 3.0

Where D.L. = S.L.

4.7

4.8