The objectives of structural design is to design the structure for stability, strength and serviceability.
The design of a structure must satisfy three basic requirements:
To prevent overturning, sliding or buckling of the structure, or parts of it, under the action of loads.
To resist safely the stresses induced by the loads in the various structural members.
To ensure satisfactory performance under service load conditions – which implies providing adequate stiffness and reinforcements to contain deflections, crack-widths and vibrations within acceptable limits, and also providing impermeability and durability (including corrosion-resistance), etc.
There are two other considerations that a sensible designer ought to bear in mind, viz., economy and aesthetics. One can always design a massive structure, which has more-than-adequate stability, strength and serviceability, but the ensuing cost of the structure may be exorbitant, and the end product, far from aesthetic.