Low-tech steel damper: square tube parts for similar tension/compression bracing behavior

Abstract

Bracing systems have been essential for lateral load resistance in buildings but are limited by low energy dissipation and susceptibility to buckling under compressive loads. Yielding dampers have been introduced to enhance these systems, but they often suffer from asymmetrical behavior in tension and compression, complex manufacturing, and difficult design processes. This paper introduces the Double Square Tube-form Yielding Parts (DSTYP) steel damper, designed to provide symmetrical behavior under both tension and compression, ease of manufacturing, and simple design via four straightforward formulas. The DSTYP damper dissipates energy using two square tube-form parts that alternate between tension and compression under axial loads. Laboratory tests and finite element analysis (FEA) reveal the damper's hysteretic load-displacement behavior. Based on FEA results, two formulas for initial stiffness and yielding strength are derived, facilitating the damper's design for use in multi-story buildings with concentric bracings. Nonlinear time history analyses of a 5-story building with chevron bracing demonstrate that the proposed dampers can reduce maximum roof acceleration and base shear by approximately 30% and 20%, respectively, compared to conventional bracing systems.