Experimental Investigation of Timber Buckling‐Restrained Braces under Cyclic Loading

Abstract

This paper presents the results from an experimental investigation of the hysteretic behaviour of a novel‐developed class of timber‐buckling‐restrained bracings (T‐BRBs). The proposed system, which has been evaluated with and without an external steel tube, consists of a steel core and an oak mass timber casing. To evaluate the hysteretic behaviour of the T‐BRB, nine half‐scale test specimens, each 2700 mm in length, were fabricated with varying configurations and subjected to cyclic loading. The results indicate that the T‐BRB bracing is prone to global buckling, premature splitting, and rupture of the casing ends when the timber casing is fastened only with screws and no steel tube is used. These kinds of failures lead to cumulative inelastic deformation (CID) ratios that are below the minimum performance requirements prescribed by AISC. However, the integration of external 5 mm and 6.3 mm thick steel tubes effectively prevents casing rupture, ensures uniform stress distribution, and facilitates the development of full inelastic deformation in the steel core. The experimental results confirm that the tube‐confined T‐BRBs exhibit highly stable hysteresis loops, enhanced energy dissipation, and improved seismic resilience and display considerable promise as a sustainable and efficient alternative to conventional BRBs in timber–steel hybrid structures.