TODD VENEZIA
NY Post Online
September 20, 2001 -- As rescue workers sift through tons of wreckage at the World Trade Center, they may soon face a hidden danger - the collapse of a huge retaining wall that encased the fallen foundation.
The Port Authority says there is no immediate threat that the so-called "bathtub" wall will give way - but experts say workers will have to shore up the concrete bulwark before all the rubble is removed.
"It seems that would be very important to the safety of the workers," said structural engineer Keith Brenner. "And just from the way that effort down there is going, I'm sure they are going to be looking into this."
The bathtub is a 70-foot- deep, 16-acre well, ringed by a concrete-and-steel retaining wall. It contains the World Trade Center's foundation along with seven stories of basements, shopping concourses, parking garages and a PATH train station.
The wall was designed to hold back the landfill that makes up much of lower Manhattan around the trade center - and give the foundation a clear path to bedrock.
The bathtub is now filled with untold tons of debris that fill an enormous, smoldering crater.
Before the attack, the wall was held in place by the trade center's basement floors and foundation. Now, without that support, some fear the only thing holding up the wall is the mass of debris.
That means recovery workers may have to perform a delicate operation and shore up the walls before the bulk of the rubble is removed.
If the walls collapse, the surrounding landfill could pour in, burying the WTC rubble, endangering surrounding buildings, and possibly lead to flooding.
"The walls require lateral support. You've got the Hudson River across the street," engineer George Tamaro, one of those leading the debris-removal effort, recently told The New York Times.
Port Authority spokesman Dave Jamison told The Post yesterday it's still too early to assess the state of the wall, but added there is no danger now of the debris pile or surrounding building shifting.
"I'm sure they'll look at it at some point and see what they may have to do to brace it," he said. "At this point, we don't know."
Such retaining walls are common around the foundations of tall buildings and usually need to be shored up after a collapse, Brenner said.
Related:
