RIGID STRUCTURAL FRAME

• INTRODUCTION OF RIGID FRAME STRUCTURE• Part of a structure• Types of structure• Framed structure• Structural load• Load bearing and framed structure• Load bearing and non load bearing wall• Advantages and disadvantages

RIGID STRUCTURAL FRAME

INTRODUCTI

ON

Rigid frame structure can be defined as the structures in which beams and columns are made monolithically and act collectively t resist the moments which are generating due to applied load.

It provide more stability. This type of frame structures resists shear, moment and torsion more effectively than any other type of frame structures. That’s why it is used in world’s most astonishing building Burj Al –Arab.

SUB STRUCTURE AND SUPER STRUCTURE

SUB STRUCTURE AND SUPER STUCTURE

Substructure is a solid base under the ground that supports a building above the ground [ super structure]

Super structure of a building is the portion of structure above foundation. It provides necessary utility of building with comfort , structural safety , ventilation, etc.

PARTS OF STRUCTURE

BEAMS

• Beam is the horizontal member of a structure carrying transverse loads. Beam is rectangular in cross section. It carry floor slab or roof slab. Beam transfer all load including self weight to the column or wall

BEAMS

TYPES OF BEAMS

Simply supported beam

Fixed beam

Cantilever beam

Continuous beam

Overhanging beam

COLUMNS• An isolated vertical load

bearing member is called column , width of which is neither less than its thickness nor more than four times its thickness.

• Pier is similar to a column except that it is bonding into load bearing wall at the sides to form an integral part and extends to full height of the wall.

COLUMN AND BEAM• Both are load carrying elements but differ in method or way of handling

load by each member That means , columns bear compression of load whereas beams bear bending movement and shear force of load.

• Similar materials are used in the construction of column and beams which are steel , timber and concrete.

• A building can’t stand without columns but can stand without beams.• Design classification of both are different. Columns are classified as

slender or short while beams are classified as T, L or rectangular.• The ties of columns and ties or shear reinforcement of beams act

differently.• One should be careful in stating behavior of each because behaviors of

both elements are different.

LINTEL

• Lintel is a short beam with its ends built into a wall. It is a horizontal structural member placed over small openings of wall for door , window, ventilator, cupboard etc.

FOUNDATION• A foundation is the lowest and

supporting layer of a structure. Foundations are generally divided into two categories – shallow foundation and deep foundation.

• SHALLOOW AND DEEP foundation Depends on whether load transfer is at deeper depths.

• Needs for these two types of foundation--soil strength , ground water condition , foundation loads, construction methods and impact on adjacent property.

TYPES OF FOUNDATION

• Shallow foundation– Column footings without or with tie/ grade beams, individual or combined wall footing, slab on grade, raft

• Deep foundation– Cassis or without sockets, end bearing or friction pile groups of influence , made of concrete [ regular or site cast] or steel.

FRAME STRUCTURE• Frame structure are the

structures having combination of beam, column and slab to resist lateral and gravity load. These structures are usually used to overcome large moments developing due to the applied loading.

1. Rigid frame structure2. Braced frame structure

FOOTING

• The lowest load bearing part of a building , typically below ground level I called footing.

• There are three main types of footing

• Strip footing• Raft/ Mat footing• Isolated / Mat footing

STRUCTURAL LOADS• Loads are external forces acting on a

structure. Stresses are internal forces that resist loads.

• The following are loads forces and stresses to be considered in designing super structures of building , bridges and culverts.

1. Dead load2. Live load3. Wind load4. Snow load5. Earthquake load6. Hydrostatic and soil pressure7. Impact load

PRIMARY LOADS

PRIMARY LOADS• DEAD LOAD consists of weight

of various structural members and weight of any objects that are permanently attached to structure. Hence , for a building, dead load include weight of columns , beams and girders, floor slab, roofing walls, windows, plumbing, electrical fixtures and other miscellaneous attachments.

•

• LIVE LOADS OR IMPOSED LOADS are , temporary, of short duration, or moving. These dynamic loads may involve considerations such as impact, momentum, vibration, slosh dynamics of fluids, fatigue, etc. Live loads sometimes referred to as probabilistic loads include all forces that are variable within object’s normal operation cycle not including construction or environmental loads.

LOAD BEARING WALL• It carries weight of the building and

distributes that load onto building’s foundation. Load bearing walls which are easiest to identify are home’s exterior walls.

• These walls carry weight of roof system. Roof trusses rest on these walls and create a continuous plane all the way down to the building’s foundation. In most residential walls, a 2nd set of load bearing walls, one on each floor, exists along centerline of home. In the basement this wall is created by a metal beam. Directly above metal beam on 1st and 2nd floors, a wall down the middle of home also helps support roof truss weight.

NON – LOAD BEARING WALL• A framed wall is any wall in

home that is not a load bearing wall. Closets are a typical example of walls which are not load bearing walls. Also called partition walls, framed walls create internal rooms in a home. They can be moved, removed or shortened without affecting the building’s structural integrity.

LOAD BEARING STRUCTURE • Load is transferred to

foundation via load bearing internal and external walls ex. Masonry houses, pyramids in Egypt. They are generally characterized by having a small window to wall ratio [ i.e. more structural wall area than window openings] and internal walls. Due to large stresses within brick or stone walls height of load bearing structures is limited.

FRAMED STRUCTURE• A framed structure is composed

of beams and columns. With load being transferred into beams via floor and then down to foundation through columns. These type of structure can have open internal spaces and clad in glass [ curtain walling] or have large windows. Ex. Modern day skyscrapers. First framed building was Home Insurance Building in Chicago built in 1884-85.

DIFFERENCE

LOAD BEARING STRUCTURE• Cost is less• Suitable up to three stories.• Walls are thicker , hence

floor area is reduced.• Slow construction• Not possible to alter position

of walls after construction.• Resistance to earthquake is

poor

FRAMED STRUCTURE• Cost is more.• Suitable for any numbers of

stories.• Walls are thinner hence more

floor area available for use.• Speedy construction.• Position of walls may be

changed , whenever necessary.• Resistance to earthquake

forces is good.

ADVANTAGES AND DISADVANTAGES OF FRAME STRUCTURES

• Advantages – One of the best easy in construction, easy to teach labor at construction side.

• Disadvantages– Span lengths are usually restricted to 40ft when normal reinforced concrete otherwise spans greater than that , can cause lateral deflections.

Selection of frame versatility and advantages over normal tradition

structures for high rise building is due to their load bearing structures

• Actually performance of load bearing structures is usually dependent on mass of structures. To fulfill this requirement, there is need of increase in volume of structural elements [ wall, slab]. This increase in volume of structural elements leads toward the construction of thick wall. Due to Such type of construction , labor and construction cost increases. In construction of thick wall there will be need of great attention which will further reduce speed of construction.

• If we contrast of load bearing structures with frame structures , frame structures appear to be more flexible , economical and can carry heavy loads. Frame structures can be rehabilited at any time and flexible in use.

THANKYOU

-------MANISHA AGARWAL