Flexural Testing of Structural Insulated Panels Before and After Creep Testing

Abstract

The effect of duration of load testing on flexural properties of structural insulated panels was investigated herein. Structural insulated panels were manufactured by a member of the Structural Insulated Panel Association (SIPA) in accordance with International Code Council-Evaluation Service Report 4689. Two panel depths 16.5 cm and 31.1 cm (6.5 in. and 12.25 in.) were tested in short duration 1/3-point bending per American Society for Testing and Materials standards. All structural insulated panels had joints or discontinuities in the foam layer in a location that was subject to shear stress during the bending tests. Failure mode for all panels was horizontal shear within the foam layer. Within each panel depth, no statistically significant differences were detected between the maximum load values before and after creep testing. This finding indicates that the creep test loading was not detrimental to the strength of the structural insulated panels. While the results were not deemed to be statistically different for the Δy_max (midspan deflection at P_max) for the 31.1 cm depth class, they were statistically different from the 16.5 cm depth class. Overall, it appeared that there was minimal effect of the creep test loading on Δy_max of the SIPs.