Behaviour of Structural Insulated Panels (SIPs) under both short-term and long-term loadings

Structural Insulated Panels (SIPs), as a load-bearing construction material, have recently attracted continuingly growing interest. They are structurally sufficient, energy efficient, easy to use in construction and more sustainable. SIPs are a composite sandwich panel system, typically made of two oriented strand board (OSB) panels and one insulation core material such as expanded polystyrene (EPS) or polyurethane (PUR). They have high strength-to-weight ratio and can resist axial, transverse and racking loads. Therefore, they can be used as structural materials for roof, wall and floor panels. An entire building structure can be made of SIPs without including many conventional construction materials such as steel or masonry. Due to the limited application and research on SIPs, the knowledge of this material is still lacking. This is exacerbated by the fact that the structural performance of SIPs has been reported varies from manufacturer to manufacturer as they use different SIP construction and connection details. In applying SIPs as structural materials, apart from addressing conventional structural issues, there is another major concern related to their long-term performance, mainly caused by creep. Both facial and core materials experience high creep behaviour, and it has been found that the creep of SIPs is predominantly caused by the core material. This paper will report studies conducted at University of Birmingham on structural behaviours of SIPs under both short-term and long-term loadings.