PERFORMANCE-BASED PLASTIC DESIGN METHOD FOR Y-TYPE HIGH STRENGTH STEEL COMPOSITE ECCENTRICALLY BRACED FRAMES

In Y-type high strength steel composite eccentrically braced frames (YEBF), link members use steel with a low yield point while beams and columns use high strength steel. This approach can reduce steel consumption and increase economic efficiency. The traditional design method for EBF is based on elastic theory; the plastic deformation is concentrated in certain stories, resulting in presence of weak layers in the structure. In this paper, a performance-based plastic design (PBPD) method is used to design YEBF with shear link (S-YEBF). Target drift and ideal global failure models are adopted as the key parameters to estimate and control the plastic behavior of the structure, which causes all links to dissipate energy under rare earthquakes. Moreover, the story drifts are uniform along the structural height, and they avoid the presence of a weak layer in the structure. A 1/2-scale model for a multi-story PBPD design of S-YEBF was designed to research the seismic performance using a shake table test. The finite element models of the 10-story PBPD of S-YEBF structures and the traditional design of S-YEBF structure were developed. Nonlinear pushover and dynamic analyses were adopted to study the seismic performance of the structures. The results indicate that the S-YEBF structures designed by PBPD method have good seismic performance, and the structures closely follow an ideal failure model. All links entered the plastic stage to dissipate the energy. The story drifts are distributed uniformly along the structural height. The PBPD structure uses less steel than the traditional design. The PBPD method for S-YEBF can be applied to various practical engineering problems.