Analysis of second-order elasticity of steel frames with semi-rigid connections

In the analysis of internal forces in steel frames, it is often assumed that the connections between columns and beams are either rigid or pinned. However, the connections have been proved to be semi-rigid theoretically and practically. FEM is used in this paper taking into consideration of second order effect and nonlinear model by Frye Morris to study the behavior of steel frames with semi-rigid connections. A comparison is made between simplified methods of horizontal notion force proposed by Code for Design of Steel Structures (GB50017) and by AISC-LRFD (1994), which reveals that the second order effect in the steel frames increases accounting for the semi-rigid connection and the simplified method proposed by GB50017 does not satisfy the semi-rigid steel frames.