The possible shear of the upper chord will change beam from flexural member to member under flexure and compression force . this is emphasised through design example . as a result ， we find that composite floor system is good for reducing the height of floor system 在组合楼盖体系设计中，笔者指出，可能的桁架弦杆剪力会使作为桁架弦杆侧向支承的梁由弯曲构件变为压弯构件，这是在与桁架体系相适应的楼盖体系设计中应该注意的一个环节。
