Following a sudden summer down pour in sunny Florida, a commercial facility’s roof collapsed causing significant property damage to very expensive electronic equipment. Near the center section of roof collapse appeared the remains of a roof drain that displayed a drainage restriction created by a smaller roof membrane opening than allowed by the size of the roof drain fitting (i.e., created a restrictive orifice). Almost immediately blame for the catastrophe was directed at the roofer and plumber who had installed the roof and drain. An investigation revealed the structural collapse included a failure of steel roof truss separating from a precast wall panel. Xray examination of the precast panel documented the designed reinforcing steel for the truss connection to be missing from the concrete panel. Further reconstruction of the rain event (with meteorologist support sing doppler recordings) determined the quantity of water from the rain event was well within the drainage capacity of the subject roof drain. Further evidence of associated steel structural connections not installed per design contributed to cyclical thermal loading of the deficient truss-precast panel connection leading up to its ultimate demise.
This case, as many others, indicate the importance of early documentation and preservation of material evidence of an accident scene and thorough analysis of the systems, and environmental factors that can contribute to such catastrophes.
