Lateral force resistance of structural insulated panels consisting of wood-based sheathing and a polyurethane core

Abstract

A structural insulated panel (SIP) is an emerging building material with a composite structure; these panels are widely used as wall, floor, or roof members. When used as a wall member, the lateral force resistance is an important index for product design and structural design. In this study, oriented stranded board (OSB) and structural plywood were used as the facing panels, and polyurethane insulated board was used as the core layer. The influences of different wall thicknesses, facing materials, module combinations, and loading methods on the lateral force resistance performance of the SIP walls were systematically investigated. Results show that the ultimate load in the racking test increased linearly with increase in the thickness of the SIP wall. SIPs with structural plywood sheathing obtained higher racking resistance values than SIPs with OSB sheathing. Lateral force resistance of the SIP walls with the 600 mm by 2400 mm module was 13.5% higher than that of the SIP walls with the 1200 mm by 2400 mm module. A decrease in the nail spacing significantly strengthened the lateral force resistance of the SIP walls. There was a 5.7% difference in ultimate shear load values obtained from tests based on the ISO 22452 and ASTM E72 standards. Failure modes of the SIP walls depended on the type of sheathing and the monotonic loading method (direct vs. multi-stage loading). The satisfying shear strengths of the SIP walls obtained in this study provide guidance for the practical use of SIPs as shear walls.