Comparative seismic behavior assessment of a new damper-equipped and conventional chevron-braced frames

Abstract

This paper presents the results of experimental studies performed on three 1/3-scale steel building frames for comparative assessment of the cyclic behavior of a Chevron frame equipped with a newly-developed damper, THDF (Torsional Hysteretic Damper for Frames) in relation to a Chevron special concentrically braced frame (SCBF) and an eccentrically braced frame with a vertical H-link. THDF is a damper with a displacement-dependent post-elastic stiffness, developed for Chevron frames. First, the SCBF was designed as a full-scale frame according to the requirements of AISC 360–16 and AISC 341–16, and scaled down to 1/3-scale according to similitude requirements due to limitations of the testing facilities. The other two frames are designed as scaled frames by adjusting their braces and energy dissipation elements so that the frames have similar levels of yield force. The frames are subjected to quasi-static cyclic tests of increasing amplitude until failure. In the case of SCBF and H-link frames, the force levels observed in the tests were higher than predicted due to oversight in the fabrication of the test specimens, which may not be the case in practice. In the case of the H-link frame, this led to early failure of the connection before the full plasticization of H-link. SCBF was tested up to low-cycle fatigue failure of both braces. The THDF-equipped frame showed stable force-displacement loops with little variation in force levels and a better distribution of energy among the stories.