Civil engineering is a professional engineering discipline that deals with the design , construction , and maintenance of the physical and naturally built environment, including works such as roads, bridges, canals, dams, airports, sewerage systems, pipelines, and railways. In civil engineering, designing means finding out the dimension of a structural member and amount of other materials (reinforcement, prestressing etc.) which will be sufficient to withstand diifferent types of loads and forces applied on that member, at the same time it will be economic and providing serviceability.

Mechanical Engineering is the discipline that applies engineering , physics, engineering mathematics, and materials science principles to design , analyze, manufacture, and maintain mechanical systems. ... It is the branch of engineering that involves the design , production, and operation of machinery.