The Showa bridge pictured at left had only recently been opened to traffic. The bridge had seven spans across the river, each supported by piers consisting of structural steel girders carrying a reinforced concrete deck. Two of the piers collapsed. The corresponding spans of the bridge collapsed and dropped into the river. The successive spans toward the west bank also dropped while one end of each span remained connected at the top of successive piers. The construction was such that one end of the girders was locked and the other end was free to slide longitudinally off the pier after about 30 cm of movement.

Image Credit: NOAA National Geophysical Data Center