Civil Engineering and our Homes – The Loads that our Houses take
An average roof slab of a 1200 Sqft House weighs 40 Metric Tons, i.e 40,000 Kgs, add another 60,000 Kgs for the walls so you have one floor weighing a whooping 100 Metric Tons, i.e 100,000 Kgs. The weight of the occupants is comparatively much less. So a House needs to be strong to take its own weight, the weight or the load caused by the occupants is of little consequence in the overall structural stability of the Building.
The Definition and Provisions of the Loads on a building to be considered for the purpose of Structural Design has been covered by IS Codes IS : 875 (Parts 1 to 5) as mentioned below and the earthquake loads are to be considered as per IS: 1893-1984
Part 1 Dead loads
Part 2 Imposed loads
Part 3 Wind loads
Part 4 Snow loads
Part 5 Special loads and load combinations
Earthquake load is covered in a separate standard, namely, IS: 1893-1984* which should be considered along with the above loads.
The House is subject to tremendous stresses arising out of its own weight and the superimposed loads and the structural design of the building is needed just to equate the strength of the components of the building to the loads they are supposed to take in the worst of situations arising any time throughout the life of the building plus a factor of safety (FOS) to keep it within safety limits even during those extreme situations.
All along the life of the Building, may be even 100 years or more, so many things are supposed to change e.g environment, the use class and pattern, the surroundings, the ground water levels and seepage problems etc. Then intermittently or continuously, during its life, a building may be subjected to man made or natural extremities of load e.g a blast, an earthquake, a big fire, a social function or a gathering in the house, extreme temperatures, a high speed gale, flooding in the area or flooding of one or more corners of the building, accumulation of snow on the roof (in snow bound areas) even some Architectural changes wanted or digging etc. within the influence area of the foundation.
* information given above has been collected from various sources online and offline and the author acknowledges their contributions.