Seismic design of multistory tension-only concentrically braced beam-through frames aimed at uniform inter-story drift

In this paper, a seismic design procedure aimed at achieving uniform inter-story drift in multistory tension-only concentrically braced beam-through frames (TOCBBTFs) is presented. The TOCBBTF is designed so that the columns and beams would remain elastic for their negligible lateral stiffness while tension-only concentric braces resist all lateral loads as a reliable way of absorbing seismic energy under seismic loading. The hysteretic energy dissipation of the tension braces can be treated as supplemental damping ratio of the structure, and lateral stiffness ratio between braces and main structure exerts a significant impact on seismic behavior of the structure. Three performance objectives of seismic design procedure aiming for uniform inter-story drift along the building height are established first. From the perspective of supplemental viscous damping and proper lateral stiffness of the structure, the seismic design method is proposed and applied to 4- and 6- story model structures to demonstrate the design procedure. Time-history analyses are carried out to verify whether the pre-specified performance objectives are achieved or not. The analysis results show that the seismic performance of the 4- and 6-story model structure designed with the proposed design procedure agrees very well with the pre-specified design objectives.