Reporting on the scene, at the time, was Mike Buchanan who later worked for WJLA TV and then as a commentator for WTOP Radio.
As recalled by one firefighter quoted by Dave Statter, rescue crews would “stand along the top of the collapsed debris and everybody would simultaneously stomp on the concrete while yelling. Then at a signal, all would stop and there would be total silence on the entire work site while people would listen for any kind of a response from underneath. Never got any, though."
Sad update, Sept. 14, 2010: Turns out that Mike Buchanan was laid off at WTOP radio in 2008. I’ve fixed that and now also mention his WJLA days.