Anything which exerts pressure or thrust on a structure is termed as load. The Basic requirement of any structural component of a building is that it should be strong enough to carry or support all possible types of load to which it is likely to be subjected. Estimation of the loads for which a structure should be designed is one of the most difficult problems in structural design. The designer must be able to study the loads which are likely to be acting on the structure throughout its lifetime and the loads to which the structure may be subjected during a short period. It is also necessary to consider the combinations of loads for which the structure has to be designed. It is ensured that the building or the structure is structurally safe, strong, durable and economical.