Timber-framed shear walls are commonly used in residential buildings to provide lateral strength and stiffness against wind and earthquake loads. Wood-based panel products, such as plywood and oriented strand board, are typically fixed to timber framing with nails or screws to provide the necessary racking resistance of a shear wall. Plasterboard is a panel product used on walls to achieve a smooth finished surface. Plasterboard provides some strength and stiffness to the wall even though its primary function is architectural; however, most shear wall tests ignore the influence of plasterboard. The aim of this study is to quantify the influence of plasterboard on the structural performance of timber-framed shear walls. To achieve this aim, six (6) timber-framed shear walls (groups P1 and P2) were fabricated with 7mm F8 plywood sheathing on one side and 10mm plasterboard on the other side and tested under a monotonic loading protocol. Results were then compared with previous test results of three (3) similar timber-framed shear walls (group M1) without plasterboard. Results show that plasterboard improved the ultimate racking strength of these shear walls by up to 53%, a statistically significant result. Shear wall stiffness and failure modes were not affected by adding plasterboard.

This project experimentally investigated some of the most common timber bracing systems used in the Australian residential construction market and was one of the world’s largest studies of its kind. The objective of the study was to verify the design capacities of these bracing systems. The study found that plasterboard substantially improves the capacity of timber-framed shear walls and that design values for most systems are conservative; however, some adverse findings of the study relate to systems with sheathing on both sides of the wall, short length walls and cross-braced walls with stud straps.

The sheathing-to-timber connection (STC) is a critical component of timber-framed shear walls. The STC provides the shear wall system with its racking resistance, while anchors and tiedowns provide resistance to sliding and overturning, respectively. Because building materials are exposed to weathering during construction, this study aims to quantify the influence of weathering on the structural performance of STCs. To achieve this aim, a total of 117 small-scale specimens were fabricated with 5 different sheathing types and 2 different timber species. Each specimen comprised 2 panels of sheathing connected to 2 short lengths of pine timber (90×35 mm cross-section), with a total of 16/2.8ϕ×30 mm (l) galvanised clouts at 45 mm spacings. Some specimens were tested under the EN 594 monotonic loading protocol and others were tested under the ISO 16670 cyclic loading protocol. Some specimens were exposed to the weather for a period of 6 months before being tested, while others were stored in an air-conditioned environment before being tested. The results show that weathering reduces the ultimate and yield capacity of STC connections by 3% and 5% on average, respectively; however, this result is not statistically significant for most sheathing types. The results varied, with some configurations having an ultimate capacity up to 16% higher and others having an ultimate capacity as much as 20% lower for weathered specimens compared to unweathered specimens. However, weathering reduces the stiffness of STCs by 61% and ductility by 50%, a statistically significant result. For most sheathing types, these findings do not support reductions to the design capacity of STCs that have been exposed to weathering.