Development of a windborne debris impact fragility curve for Cross-Laminated Timber using experimental testing: Fid-Bau Portal

Development of a windborne debris impact fragility curve for Cross-Laminated Timber using experimental testing

Stoner, Michael / Pang, Weichiang

Abstract Cross-Laminated Timber (CLT) is an engineered wood product with high rigidity, dimensional stability, and desirable environmental properties. Because of these characteristics, it presents the potential to resist the impact loads associated with windborne debris in both tornadoes and hurricanes. Full-scale experimental debris impact testing was performed on 3-layer CLT in order to determine its response to debris impact loading scenarios. A variety of missile masses, speeds, and impact locations were tested to determine this response. Various forms of failure were observed including missile perforation, excessive backside deflection, and dislodgement of debris on the backside of tested panels. Analysis of the experimental data was then performed with the goal producing a debris impact fragility curve for CLT. The resulting curves were based on relating a missile's kinetic energy with the probability of failure as defined by relevant testing standards. The results of this study point towards 3-ply CLT having a high likelihood of surviving impacts from EF-2 and EF-3 level missiles with a decreased likelihood of surviving debris from EF-4 and EF-5 level events. For qualification as a material for safe rooms, thicker panels and additional connection design would be required.

Highlights • The ability of 3-ply CLT to resist windborne debris was experimentally determined. • Performance varied based on impact location, axis orientation, and connection type. • Panel-to-panel connections exhibited increased vulnerability to windborne debris. • Calculated fragility curves predicted 60% probability of failure from EF-5 debris.