Forensic Analysis of a Large Volume Rack Building Impacted by Hurricane Michael (2018)

Abstract

Metal building systems (MBS) are extremely common and frequently used in commercial, industrial, and warehouse applications thus serving critical roles in local economies. Damage sustained to these buildings through extreme events, such as hurricanes, can prove devastating and prolong recovery of communities. However, extreme events near design values occur infrequently in the United States providing little opportunity to evaluate building design. Hurricane Michael (2018) was such an event. A detailed field investigation was conducted on the Watson’s Marina building, a metal rack MBS. Watson’s Marina experience a partial collapse of the windward wall with estimated windspeeds below design windspeeds. A combination of LIDAR data, arial and ground based photography, and design data was used document damage and to create a numerical model using the commercial structural analysis software SAP2000. Both static wind loads calculated with ASCE 7-10 and dynamic wind loads from wind tunnel data were used to simulate Hurricane Michael’s effect on Watson’s Marina. Overall the study found that failure was initiated due to roof purlin buckling in windward bay roof purlins. Three primary reasons were identified for roof purlin failure, an unanticipated load path, underestimation of windward wall design wind pressures, and greater than expected internal pressures. Identification of these factors provides a guide for future mitigation and gives direction for future research.