Abstract
The federal highway administration (fhwa) assisted in the national transportation safety board (ntsb) determination of the cause of the collapse of the spans of the northbound us-51 bridge over the hatchie river on april 1, 1989. The collapse resulted in five vehiclesgoing into the river and eight people being killed. The bridge site, field observations, stream stability, analysis of aerial photographs, model studies, and foundation analysis are discussed. This paperappears in transportation research record no. 1279, Hydrology and environmental design 1990.