In resoect to a composite beam-column made of a H-shaped steel having relatively large width-to-thickness ratio, the followings have been comprehended from experimental results on its plastic mechanical behavior underS-point bending. 1. Concrete-crash does not much influence plastic mechanical behavior, which is recognized stiffening effect by concrete. 2. In case of yield of web by shear force at the maximum load, its in-plane shear deformation increases plastic deformation capacity. 3. Plastic deformation capacity is linearly corresponding to [numerical formula], which can be also evaluated with the previous results on the stub columns under compression.
