Structural Insulated Panel (sip) fractional creep deflection

Structural Insulated Panels (SIPs) show advantages In strength, thermal performance and speed of installation when compared to stick built residential and light commercial construction. Manufacturers are increasingly concerned with substantiating the long term performance of their product to code officials, consumers, distributors, specifiers and designers and creep tests consume a significant part of the structural testing protocol. This paper presents a fractional deflection analysis designed to predict the composite SIP creep behavior from the creep behavior of the respective face and core component materials. The experimental plan includes testing the effects of SIP thickness, core type, and stress level. When optimized this technique could minimize the size and number of specimens required to substantiate weep behavior of full scale sandwich SIPs. The fractional creep deflection technique was reasonably acceptable for predicting the three month relative deflection to within -18% + 11% for EPS and Urethane SIPs in three thicknesses in the linear viscoelastic range.