Free preview · Where the load comes from
Structure is the argument a building makes with gravity, and it is an argument you can follow without solving a single equation by hand. Start with where the load comes from. Dead load is the permanent weight of the building itself: slab, beams, walls, floor finish, plaster, waterproofing, the stone cladding someone added in month nine. It is predictable and it dominates in concrete construction. A 125mm reinforced concrete slab weighs roughly 3 kN per square metre before finishes; a 230mm brick wall adds around 4 kN per metre run per storey height. These two numbers alone explain most of a residential frame. Live load is the changing weight of use: people, furniture, stored goods. Codes assign it by occupancy — around 2 kN per square metre for residential rooms, 3 for balconies and corridors, more for assembly or storage. It is applied where it can occur, not where it usually does. Then the environmental loads: wind, which matters most on tall, light or coastal buildings; seismic, which in India is governed by zone and matters everywhere from Zone III upwards; and water and earth pressure on anything below ground. The designer's takeaway is not the arithmetic but the instinct: heavy things want short spans and direct support, and every kilogram you add at the top must be carried all the way down.