ANALYSIS ON DAMAGE AND FAILURE BEHAVIOR OF STEEL FRAME WELDED CONNECTIONS

In order to evaluate the effect of damage on buildings and predict the failure forms of structures, a series of tests with different configurations were carried out subjected to various cyclic loading patterns. Typical failure modes and probable damage reasons were discussed in depth. Cumulative hysteretic energy, maximum deformation, maximum load, yield displacement and yield load were calculated for all connections. Then, the various index models were summarized and applied in all the tests, and the damage developmental curves of ten damage indices for each connection were obtained based on these basic parameters. Finally, the prediction and evaluation capacity of various damage models were compared for describing the degraded performance and failure modes. The tests and analysis results show that: The loading history significantly affected the distributive shapes of the damage indices. For “large amplitude”loading, specimens indicated a progressive failure while a sudden failure for “small amplitude”. Different damage indices have their own scope of application. The selected parameters of the damage indices have great effect on the degradation curves. The model with only displacement variable was recommended, which is easy to be formulated and embedded in application program.