Steel structure buildings have developed fast recently and all kinds of structural styles or special shape built-up member is widely used

so it is essential to take careful consideration into reasonable simplification of the special steel shape-lumber's computation.Based on the research on several forms commonly used in the steel structure split-level beam

are compared the result on special shape beam of a certain steel structure store bearing concentrated load.It is found that there are great differences between simplified computation and actual computation on whole section about the form of T-shape beam added to I-shape beam.Combined with the stipulation to the bending strength calculation of the member in"code of the steel structure design"

the biggest shearing stress of the cross section is calculated according to the derivation formula of shearing stress and the errors between the theoretical calculation and the finite element computed result are compared

and conclusion are made that the limitation to the simplified computation is dramastic.Therefore

suggestion is made that such heteromorphous steel grider should take the whole section as the computation object.