Experimental evaluation of OSB-faced structural insulated panels subject to blast loads

Abstract This paper reports the results of an experimental program to quantify the blast protection provided by as-built and strengthened structural insulated panels (SIP) subjected to short-duration uniform pressure loads in a blast load simulator facility. SIPs are used in residential and light-commercial buildings. The SIPs used in this study had an overall thickness of 117 mm with 11 mm thick oriented strand board (OSB) facers and a 95-mm thick polyurethane closed-cell foam core. This type of sandwich panel provides improved energy efficiency and reduced construction time. A total of eight panels were tested in four different configurations: (1) as-built SIP design with standard connections, (2) as-built SIP design with strengthened roof connection, (3) flexural strengthened SIP using galvanized steel straps with strengthened roof connections, and (4) flexural strengthened SIP using fiber reinforced polymer (FRP) wallboard with strengthened roof connections. Each panel in this experimental program was 1.2 m by 2.4 m and was tested independently. The panels were subjected to two to five incrementally increasing pressure-impulse combinations. The first was a low pressure shot to verify the elastic performance of the SIP. The magnitude of the pressure-impulse combination for the subsequent shots increased until ultimate failure of the panels. By strengthening the roof connection, the as-built panels withstood a 27% larger impulse. The steel strap and FRP flexural strengthening with the strengthened roof connections led to a three-fold and five-fold increase in impulse resisted, respectively, when compared to the as-built SIP with standard connections. The results of the experimental study were validated using single-degree-of-freedom (SDOF) models. The SDOF analysis included an elastic resistance function for each panel configuration. The SDOF analysis estimated displacements 9% larger than the experimental results on average. The analytical model was more conservative for the lower pressure shots indicating that one-way behavior of SIPs subjected to shortduration uniform pressure loads may be reasonably estimated using fundamental bending mechanics. Overall, the results of the experimental and analytical study indicated simple strengthening methods may be used to significantly improve the blast resistance of SIPs.