SEISMIC BEHAVIOR OF GABLE FRAME CONSISTING OF TAPERED MEMBERS

This paper reports the dynamic responses of a one-fifth-scale gable-frame structure composed of tapered members subjected to El Centro earthquake ground motions, using a shaking table. The test structure was designed according to the American Institute of Steel Construction (AISC) working stress design method. The width-thickness ratio of the flange and the depth-thickness ratio of the web of the members satisfy the requirements of a compact section. The unbraced length also meets the criteria for a compact section based on the dimensions of the shallow-end cross section. Failure of the test structure is due to lateral buckling of rafters. No local buckling prior to the lateral buckling is observed. The experimentally determined ultimate strength of the test structure is compared with those predicted by the codes AISC load and resistance factor design (LRFD), AS 1250, and BS 5950. The experimental results are also compared with those of a similarly designed gable frame composed of prismatic members, tested under similar conditions.