A second-order inelastic analysis of plane steel frames using a work-increment-control solution technique

A refined plastic hinge analysis method, known as one of the most effective and practical second-order inelastic analysis methods for steel frames, is able to evaluate the ultimate structural behavior of steel frames by considering the geometric and material nonlinearities. However, an appropriate advanced nonlinear solution technique has to be incorporated to help structural engineers perform the rational design of steel frames by predicting the ultimate strength and post-failure structural behavior accurately. In this study, a refined plastic hinge analysis method, combined with a work-increment-control solution technique with an iterative procedure in incremental loading steps, was presented in order to overcome the shortcomings of the load-increment-control solution techniques employed in previous studies. In the workincrement- control solution technique of present study, one convergence criterion refining the problem of using two convergence criteria in the conventional increment/iteration procedure of work-increment-control solution techniques and an automatic incremental algorithm calculating the load factor and the magnitude of incremental work for next incremental loading step were employed. To verify the accuracy and appropriateness of the present approach, three representative plane steel frames employed in previous studies were analyzed, and the analysis results were compared with those by other approaches. The present approach, that evaluated fairly accurately the load-displacement relationships, ultimate loads, plastic hinge numbers and locations, and the post-critical responses up to the formation of collapse mechanism of the plane steel frames, proved to be acceptable.