Considering different shaped beams like I-beam or T-beam or hollow square beam or hollow rectangular beam - what effect will the same live load have on deflection and shear and bending moment of each?

Answer 1

There isn't a way to answer this question because of the variation possible in the different beam shapes. Web and wall thickness can vary greatly, even if we throw out an arbitrary "standard" like making all the beams equal in cross-sectional area. No way this is gonna be testable in any lab. The engineering director would kick you out and tell you to write some standards for comparison. We can make a few statements that shed some light on the difficulty of the problem. A single beam is under stress just by its weight, and with a live load, the different types of stress increase. There are a number of different forces acting on the beam, and beams of different shapes will react differently to the same loads, whether they be static, live or dynamic. Different steel shapes are used in different applications to take advantage of the strength characteristics of those different shapes. For instance, in a standard I beam, the majority of the loads are carried by the top and bottom flanges and the strength of the beam is increased as the web depth becomes greater. Links are provided, and it will be helpful to just skim the introductory parts of the articles. Going completely through the posts with understanding requires some pretty heavy duty math knowledge. Surf on over and check things out.