COLUMNS

Vertical members which will transfer load from the horizontal members ( beam, roof etc.) to the underlying foundation or structure Columns carries compressive load. It should not buckle (lateral displacement) or crush under load.

Based on the material of construction Classification – Based on the material of construction Wooden Columns Concrete Columns Brick Columns Stone Columns Steel Columns Composite Columns

Concrete columns

Brick columns

Stone columns

Natural stacked stone columns

Classification – Based on the slenderness ratio slenderness ratio = effective length Least lateral dimension Short Columns Slenderness ratio < 12 Failure by Crushing Long columns Slenderness ratio > 12 Failure by Buckling

Based on the cross-section Classification – Based on the cross-section Cross section of columns 10

Classification – Based on the position of loading a) Axially loaded Columns b) Eccentrically loaded Columns P P e (a) (b)

Classification – Based on the support condition

Tributary Areas A column generally picks up load from halfway to its neighbours It also carries the load that comes from the floors above 7/39

Extremely common structural element Beams Extremely common structural element In buildings majority of loads are vertical and majority of useable surfaces are horizontal Beams support loadings that are applied perpendicular to their axes. If they are designed on the basis of strength, they must resist allowable shear and bending stresses. 1/39

Structural Members for transferring vertical loads horizontally Beams Structural Members for transferring vertical loads horizontally action of beams involves combination of bending and shear 2/39

Requirements stability - Should not fall over adequate strength - Should not break stability - Should not fall over adequate functionality – Should not deflect too much 3/39

What do we need to know span - how supported loads on the beam material, shape & dimensions of beam allowable strength & allowable deflection 4/39

Tributary Areas A beam picks up the load halfway to its neighbours Each member also carries its own weight this beam supports the load that comes from this area span spacing 6/39

Dead Loads on Elements Code values per cubic metre or square metre Multiply by the volume or area supported Length Height Thickness Load = Surface area x Wt per sq m, or volume x wt per cu m 8/39

Live Loads on Elements Code values per square metre Multiply by the area supported Area carried by one beam Total Load = area x (Live load + Dead load) per sq m + self weight 9/39

Loads on Beams Point loads, from concentrated loads or other beams Distributed loads, from anything continuous Distributed Load Point Load Reactions 10/39

What the Loads Do The loads (& reactions) bend the beam, and try to shear through it Bending Shear 11/39

Beam supported on roller and hinge 29

A beam that is fixed or anchored at one end and free at the other end Cantilever Beam A beam that is fixed or anchored at one end and free at the other end H  M R V

A beam that spans beyond the supports is called overhang beam Overhang may be on one side or on both sides W

Statically Determinate Beams Beams in which the reactions of the supports may be determined by the use of the equations of static equilibrium are called statically determinate beams. The values of these reactions are independent of the deformations of the beams. Eg: Cantilevers, simply supported beams, overhanging beams etc. 32

Statically Indeterminate Beams If the number of reactions exerted upon the beam exceeds the number of equations of static equilibrium, then the static equations must be supplemented by equations based upon the deformations of the beam. This type of beams are called statically indeterminate beams. Eg: Propped Cantilevers, fixed beams etc.

Cross section of beams 34

Based on the material of construction Classification – Based on the material of construction Wooden Beams Concrete Beams Stone Beams Steel Beams Composite Beams

Composite Beam

Walls

The primary function of a wall is to enclose or divide space of the building to make it more functional and useful Walls provide privacy, afford security and give protection against heat, cold, sun and rain Walls provide support to floors and roofs

Requirements of a good wall A good wall has following characteristics: Strength and stability Durability and fire resistance Sound insulation Adequate protection from weather changes like wind, rain etc. Low initial and maintenance costs Horizontal joints should be continuous and vertical joints should be staggered

Types of wall Walls may be basically divided into two types: Load-bearing walls Non load-bearing

Load-bearing walls are those designed to carry super-imposed loads (transferred through roofs etc), in addition to their own weight (self weight) Non load-bearing walls carry their own load only. They generally serve as divide walls or partition walls.

Load bearing walls may further be divided into following types: Solid masonry wall Most commonly used Built of individual blocks of material, such as bricks, clay or concrete blocks or stone, usually in horizontal course cemented together with suitable mortar.

Cavity wall A Cavity wall or hollow wall is the one which consists of two separate walls, called leaves or skins, with a cavity or gap in-between. The space between the leaves is either left as a continuous cavity or filled with non-load bearing insulating and water proofing material.

Faced wall It is a wall in which the facing and backing are of two different materials which are bonded together to ensure common action under load.

Veneered wall It is a wall in which the facing is attached to the backing but not so bonded so as to result in common action under load.

Retaining walls Constructed to retain the earth filling Required in the construction of hill roads, abutments etc.

Road Train retaining wall

highway

High-rise building basement wall

Non load-bearing walls Partition wall Thin internal wall which is constructed to divide the space within the building into rooms and areas

Non load-bearing walls Panel wall Mainly used in framed construction Supported at each storey but subjected to lateral loads

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