Experimental Evaluation of the Durability of Timber–Steel Hybrid Connection Interfaces under Accelerated Ageing
Abstract
Engineered wood products are increasingly used in structural applications for their favourable strength-to-weight ratio, with uptake further driven by the global shift towards low-carbon construction; however, their structural performance can be limited by a low modulus of elasticity and brittle behaviour. Hybridisation with steel therefore emerges as an effective strategy to improve stiffness, strength, and ductility, provided that continuous connection interfaces along the member length between the timber and steel can maintain strong composite action. The durability of such connections remains uncertain because timber undergoes moisture-induced swelling and shrinkage, while steel exhibits comparatively smaller temperature-driven dimensional changes, which may lead to stress concentrations and connection degradation. This study investigates the long-term performance of continuous laminated veneer lumber (LVL)–steel connection interfaces using two accelerated ageing protocols, namely a modified ASTM D1037 wet–dry cyclic method representing severe exposure and a controlled temperature–humidity variation regime representing more realistic in-service conditions. Four connection configurations are examined, incorporating adhesive bonding, mechanical fastening, or a combination of both. The shear performance of the aged connections is evaluated and compared against unaged reference specimens. Adhesive-based connections showed pronounced degradation after ageing, including complete delamination under the modified ASTM cycling, whereas screw-based connections exhibited greater resistance to ageing-related degradation. Overall, the findings demonstrate that cyclic moisture exposure can strongly influence the performance of continuous timber–steel hybrid connections, and while adhesive bonding can provide high initial stiffness and capacity, its durability remains vulnerable under severe wetting and drying conditions, indicating the need for further research into improved adhesive formulations and surface preparation methods.
Reference
Abdulaziz Abdulmalik; Benoit P. Gilbert; Hong Guan; Tuan Ngo; Alex Remennikov. (2026). Experimental Evaluation of the Durability of Timber–Steel Hybrid Connection Interfaces under Accelerated Ageing. Elsevier BV. https://doi.org/10.2139/ssrn.6506529
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