Important of various types of loads on a building structure

The types of loads acting on structures for buildings

  • Dead load
  • Live load
  • Wind load
  • Earthquake load

Dead load (D.L)

It is defined as the force whose magnitude, positions and direction remain constant. It is the load of the materials used in the construction of the building i.e. self-weight of different compounds of the building like the floor, walls, plaster, doors, windows, beams, columns, slabs etc. A dead load of any such part is calculated by multiplying its volume by unit weight of the material. The unit weight of the material. The unit weight of common material used in building construction is given in I.S – 875, 1967

Building Material Unit Weight(KN/m3)
Stone 20 to 28
Bricks 20 to 24
Steel 78
Plain Cement – concrete 22

Live load

It is the movable superimposed load acting on the structure. It comprises of the weight of occupants, furniture, equipment, machinery etc. it is considered to be uniformly distributed load acting on the area. The minimum live load to be for design depends upon the type of building as shown in the table. Their maximum magnitude, worst position, and direction should be taken into account. I.S 875-1964 gives minimum live load per square meter of the floor area as equivalent static uniformly distributed loads.

Types of floor Minimum live load (KN/m)
residential building, hospital 2.00
office room, small workspace 2.50
Steel 78
bank and reading room 3.00
classrooms, assembly halls for lightweight 4.00

For multistoried building, while designing columns, wall and foundation, full load on each floor is not considered and reduction in live load is considered, as all floors are not likely to be simultaneously loaded. The live load for upper floor is reduced by applying reduction factors as shown in the table.

No. of floors Reduction in live load
First floor No reduction
Second floor 10%
Third floor 20%
Fourth floor 30%
Fifth floor 40%

Wind load

Wind load is effective in case of tall building. When the wind is obstructed by the structure is exerts a pressure it exerts a pressure on a structure known as wind pressure.

Earthquake load

The effect of the earthquake is taken equivalent to imparting acceleration to the foundation in the direction in which the wave is traveling.

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