摘要
with the constant popularity of the precast assembly gasification, the application of the composite section beam which can change into different sections is wilder. This passage, based on the hypothesis that the interface is smooth, simplify the double composite section beam and deduce the anchorage-bolt-shear and composite-section-beam-bending-capacity formulas when there is a slip on the interface in elastic stage. Moreover, it contains some prospect and summarizes of the later research.