Bridge collapse puts spotlight on rapid building technique

The deadly collapse of a pedestrian bridge in Florida has cast a spotlight on a rapid construction technique widely used around the U.S.

It is called Accelerated Bridge Construction, or ABC. It involves assembling large sections of a span offsite, and then moving the massive pieces into place.

The technique eliminates the lengthy road closings and other traffic disruptions that can result when a bridge is built out over a highway piece by piece.

In the Miami-area disaster that killed at least six people on Thursday, the question is where was the fatal mistake — in the design of the bridge, in its construction or in the materials?