Experiment on Non-compact H-shaped Members and Frames Subjected to Cyclic Loads and the Prediction of Capacities

A series of cyclic loading test were carried out to investigate the performance of steel members with non-compact elementsas well as the frames composed of these members. The tests show that, in general, the members reach their ultimate early anddeteriorate quickly, but both the members and frames can develop enough non-elastic deformation and keep a certain resistancenecessary to prevent from complete collapse. The test results provide a foundation for the evaluation of the capacity of the non-compact element members and frames. A member section based capacity prediction method is proposed ignoring the so-calledP-Delta effect due to the relatively small axial force ratio of the light weight steel beam-columns, while the concept of effectivearea is adopted. It is proved that the ultimate is able to be predicted. By using the procedure to compute the member capacity,mechanism analysis is also tried to predict the ultimate of the frames under lateral cyclic loads. Though the failure type of thesteel beams and columns is different from those which have full plastic capacity, the simplified method is proved to be ableto predict the ultimate satisfied. Furthermore, two criteria are provided to ensure the necessary capacity and ductility while thenon-compact or slender members are applied in the seismic zones; and corresponding limitations of ratio of width to thicknessof member plates are further suggested to satisfy the two criteria.