Learning from disaster: A talk with Gene Corley

W. Gene Corley is a senior vice president at Construction Technology Laboratories Inc. in Skokie, Ill. He is also a fellow with the American Society of Civil Engineers (ASCE). Corley has participated in or led numerous structural investigations into building failures around the world, responding to earthquakes and other natural disasters, in addition to unnatural disasters caused by terrorism.

In that role, Corley led the Federal Emergency Management Agency's 1995 performance assessment team that examined the bombing of the Alfred P. Murrah Federal Building in Oklahoma City. He is now in a similar role, leading the ASCE investigation into the World Trade Center's building performance on the morning of Sept. 11, 2001.

Q Where were you on Sept. 11?

A I was in my office in Skokie on a conference call with other ASCE members discussing another study that we were already doing. One of us was in New York and another was on a cell phone in Washington, not far from the Pentagon. The rest of us watched it on television and we knew what could happen. It was just terrible.

Q You've watched the unedited video of the fire and collapse as much as anyone. What does it show?

A I have seen a lot of horrible things in my life (from other disasters), so you somehow learn to take away what you need and minimize the effect of the rest. You just have to turn away from some scenes, but other images are very instructive. For instance, in some instances you can actually see some of the steel columns just glowing from the heat of the fires.

Q What did that tell you?

A Subsequent investigation of the steel members and the connections made us realize that much of the fireproofing had been shaken off by the impact of the planes. The beams sagged and fireproofing just slid off. Of most significance, though, we saw that connections for transfer beams and trusses need greater fire protection. And such fireproofing needs to still be effective under deformation, after impact.

Q What other recommendations are in the report?

A Well, people can read our whole report to Congress online at www.fema.gov, but basically, we make five main recommendations:

1) Buildings at higher risk need a lot of redundancy and robustness in their structural systems. That's why the Trade Center was able to stand so long;

2) Fire resistance needs to relate to the fire load and connections need to be fire-rated. We need more test data here;

3) Sprinklers need to be reliable and redundant. The Trade Center fires all burned so long because the impact of the planes had cut off the main water supply for the sprinklers;

4) Exit areas (which were clustered in the core of the building) need greater strength and redundancy; some walls actually collapsed onto the stairs, blocking the escape path; and

5) Exit areas also need separation. Most in the towers were clustered in the core of the building.

Q Do you have faith that Congress will respond to these recommendations appropriately?

A It was my belief that the House Committee was working hard to determine how to do a better job in future studies. In particular, (they were) looking for ways to keep the public informed and to make it easier to obtain the needed data in a timely manner.

Members of the committee seemed particularly interested in satisfying the voters in their district (as is appropriate). It was my impression that (they) expected that we would accomplish less than we did in the first phase. However, they seemed to understand that much more work is needed. Their actions appear to be aimed toward providing the needed resources. And $16 million already has been appropriated for that purpose.

Q What should be done with Ground Zero?

A I feel very strongly about this. We ought to put very tall buildings right back there. A memorial makes sense, but an appropriate monument tends to bring buildings back into the site. If it doesn't, to me, that gives away too much to the terrorists.