THE SIMPLIFIED FORMULA OF NATURAL PERIOD FOR STEEL FRAME WITH SEMI-RIGID CONNECTIONS

Extensive studies show that the behaviors of semi-rigid connection greatly influenced the dynamic behaviors of structure. Changed the values of parameters, the natural period of basic structure is calculated with the THEASF program, and the relations between the natural period and each parameter are obtained. A simplified formula of natural period for steel frame with semi-rigid connection is obtained, which can be considered the effects of all parameters of structure. The numerical results show that this simplified formula is reliable and can be used in preliminary seismic design of this kind of structure.