Experimental and numerical study on an adjustable steel façade connector for hybrid timber-concrete structures

This study investigates the structural performance of a novel steel connector featuring a serrated interface, developed for attaching timber frame façades to reinforced concrete slabs in hybrid construction. Four full-scale specimens were tested under two representative loading scenarios: combined wind suction and gravity load (Configuration 1), and pure gravity load (Configuration 2). Configuration 1 exhibited a tension–shear response governed by brittle fracture of connection bolts, whereas Configuration 2 showed a ductile plate-dominated behavior characterized by progressive counterbore tear-out. These two configurations illustrate distinct load-transfer and failure mechanisms expected under different façade loading conditions. Finite element analyses in LS-DYNA accurately reproduced the load–displacement behavior and captured the transition from bolt-governed fracture to plate-dominated tearing. A semi–analytical component-based model, calibrated against experimental and numerical results, provided consistent predictions of stiffness and resistance. The results further indicate that, under the considered serviceability and ultimate limit state load cases, the connector remains within the quasi-elastic range, highlighting its practical suitability for façade applications. The findings also emphasize the importance of considering both combined and gravity-dominated loading in façade connection design.