News article on WTC rebuild planning, Oct 2002

NYC 9/11 Public Portal Document

can’t toe rebuilt without new Wall By Graham Rayman STAFF WRITER The World Trade Center “bathtub,” which keeps out tile Hudson River, suffered so much damage on Sept. 11 that a new wall will have to be added Wore tie-backs have been drilled and installed at the site permanent rebuilding can occur, the engineer who About 1,000 in total will be installed. designed the wall and leads the repair projec* said The abolition of Building 6 along Vesey Street on yesterday. the north side of the site took out Boor slabs holding The new determination adds another element oi up ihe wall, a result, workers wiU have to install complexity to the monumental reconstruction of the more than 100 additional tiebacks in a section trade center site, which already involves extensive known as “the donut.” repair of the existing wall called the slurry wall — Workers have currently reached about seven sto­ major subway and PATH projects, and debris recov­ nes deep. As the debris removal project reaches ery. “The slurry wall is not suitable for reuse in a per­ lower and lower, workers are finding an increasine manent situation because it suffered so much ran­ amount of water due to increased water pressure. dom damage,” said George Tamaro, who directed its Engineers have recorded leaks of 100 to 200 gal­ original construction for the Port Authority in 1967. lons per minute in places ontheslurrvw^n “It will serve adequately as a temporary measure^ “It’s an ongoing problem 'that every day we’re find­ but after five to eight years, I would get uncomfort­ ing more leaks,” said Pablo Lopez, an engineer with Mueser-Rutledge. __ able about it,” he said. “I just don’t like some of the To plug the lealis, workers with the New Jer- things I’m seeing down there.” sey-based MoreTrench Machine Co. feed rope treat­ Tamaro, a partner at Mueser-Rutledge Consulting ed with an expansion chemical into a hole in the wall Engineers, believes that a second interior waH — or until the void is filled, then intercept the crack ami “liner wall” — must be constructed to augm^t the pump in sealing paste, company president John original “bathtub.”-The project would cost $16 mil­ Donohoe said. lion to $20 million, he estimated. The company has also installed a series of wells “It’s not an insurmountable job,” Tamaro said. “li outside the bathtub to lower the level of the ground wotdd be part of the process of building Ihe base­ water, which in turn reduces pressure on the wall. ment.” Pumps are also being used to get rid of the water, Larry Silverstein, who holds the lease on the .tirade and engineers hope to use the trade center’s origin^ center site, met with Tamaro recently on the possibil­ '’■fosel sump pumps as wdl. ity that the liner wall was needed, Silverstein spokes­ man Howard Rubenstein said. Silverstein will seek to meet with Tamaro “tomor­ row or as soon as possible to see what should be done,” Rubenstein said. A Port Authority spokesman did not return a phone call. Hoe lang, a professor of geotechnical engineering at Columbia University, said such a project will add time to the overall reconstruction of the site. “The w^.ismot something that can be permanently re­ paired so this is probably the best solution.” Ncoschy The bathtub wall bisects the trade ceate s^pn a noiih-to-south line at Greenwich Street, and/con- tainsthe footprints of both towers. The walll^^sef -wjthin-6 to 16 feet of the 1 and 9 subway .tUH^&i^f ;^ee feet thick and as deep as 100 feet, into.bedrock with cables attached with tie-ha^. ' The structure of the towers supported O wall -but-many of the floor slabs that suppbrt^^^ wal were faocked out when the buildings cO^_p^. Th< dfferis iteelf has largely held up the i^^^^e pi^-live months. Some areas were unsupport^. Me debris has shifted so mutirithat^oaip-day, f huge construction “grappler” dropped feet with the-C^er inside, knocking himunconsaous. time and under intense forces, sectiot^fthe i^^^an to shift, OnOct,7,:a long<g<^pp^ to ebon of&e sl^ a mputer datashowed;'Workers uat^^^ers

^oved a foot or more. . J, u ’an;^tt^^ever

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