Experimental study of multiple power-actuated fastener connections in shear wall structures

Hybrid structures combining cold-formed and hot-rolled steel members offer significant advantages in construction efficiency and structural performance over conventional single-material systems. This paper presents an experimental investigation into the behaviour of power-actuated fastener (PAF) connections in shear wall systems joining high-strength to mild steel members. A newly developed shear test rig was designed to replicate realistic in-panel loading conditions while overcoming testing limitations of conventional single lap-joint methods, such as top-sheet curling and net-section tension failure. Forty-eight connection tests were conducted using two and six PAFs, incorporating three fastener types from two manufacturers. High-strength cold-reduced steel sheets (1.2, 1.5, 1.9, and 2.4 mm thick) were attached to 6 mm mild steel bases. The experimental results revealed no significant group effect on the ultimate strength of connections with multiple PAFs in a single row compared to single-fastener connections, for both primary failure modes: top-sheet bearing and fastener pullout-by-shear. Another key finding was that connection strengths governed by top-sheet bearing were well predicted using a bearing coefficient of 3.4, as recently proposed in the literature, improving prediction accuracy by 8.6% compared to the current codified value of 3.7 in Australia/New Zealand (AS/NZS 4600:2018) and North American (ANSI/SDI AISI S100–24). These proposals were calibrated and confirmed using a combined dataset from this study and those relevant in the literature. • Experiments on power-actuated fastener (PAF) connections in shear wall structures were conducted. • A novel test rig was developed and commissioned for testing power-actuated fastener (PAF) connections under pure shear. • Tests on two- and six-PAF connections were conducted using three different PAFs and four plate thicknesses. • The primary failure modes observed across the test specimens were sheet bearing and pullout-by-shear. • Experimental results indicated no significant group effect on the ultimate strength of multiple-PAF connections.