Usually, the root causes of a failure or accident are difficult to isolate and quantify. The causes may be a combination of interrelated deficiencies. This is one reason for the complexity of construction disputes and the confusion that often accompanies failure litigation. Failure of the Tacoma Narrows Bridge in 1940 led tosignificant advances in wind engineering and the design of lightweight structures. For example, in the 1970s, a number of failures caused by corrosion occurred in reinforced concrete parking garages in the eastern United States.
Parking structures are among the most vulnerable constructed facilities.
They are exposed to a wide range of fluctuating thermal conditions. Vehicles deposit corrosive de-icing salts used on roadways onto the parking deck surfaces. These surfaces are not rinsed periodically by rain, as is the case for most highway structures. Parking facilities are utilitarian structures, low on the typical owner's maintenance priority list. Investigation of a parking structure failure usually uncovers contributing factors from every category in the list of failure causes.