Beam-to-column connection with cantilever beam high-strength bolted-splicing in rigid steel frame is widely used in multi-stories or high-rise buildings and industry workshops in the USA and Japan, which is also the recommended connection type in our Technicall Specification for Steel Structure of Tall Buildings and Code for Seismic Design of Buildings.

To apply this novel method to design of steel portal frames, the integrated nonlinear analysis, the assessment of frame systems and the practical design formats of steel portal frames with tapered members were studied.

Employing a non linear finite element analysis program, which is designed especially for the calculation of the limit temperature of the steel portal frames with the tapered members against fire, authors carries out research on the influence of a number of parameters on the limit temperature of steel portal frames subjected to fires.

The calculation formulas of the end moments,the rotation rigidity and the transmission coefficient were derived by using three parameters mechanical model to simulate the moment rotation of beam-column connections of semi-rigid steel frame and helical spring to simulate semi-rigid connections of the nodes.

The coupling element-free Galerkin with finite element method for semi-rigid steel frames is given.