Forensic Investigations into the Performance of Large-Volume, Low-Rise Buildings Affected by Hurricane Michael (2018)

Hurricane Michael made landfall near Mexico Beach, FL, on October 10, 2020, as a Category 5 hurricane with peak gust wind speeds over 70 m/s. Following landfall, the authors conducted forensic investigations of twenty-three large-volume, low-rise buildings in Panama City, FL, that failed in below-design conditions. The buildings represented multiple structural systems, including pre-engineered metal buildings, precast tilt-up concrete systems, and metal rack buildings, and represented a range of years of construction. This paper describes the forensic assessments and observed failure mechanisms. It further details the load paths in three case study buildings and hypothesizes regarding the principal factors involved in the premature failures, informed by static and dynamic analysis of the structural systems through 3D, linear elastic finite element models. The analysis demonstrates the critical importance of the longitudinal load path through the end bay of the windward wall in the observed collapse mechanisms.