More Cement Needed For Tunnel Under Allegheny RiverPOSTED: 11:36 am EDT July 26,
2007 PITTSBURGH -- The Port Authority of Allegheny County said it will need about four times more cement than expected to strengthen the soil for the $435 million North Shore Connector.Drilling is expected to start in about two months for the project, which will connect Downtown with the North Shore via a trolley tunnel under the Allegheny River.The extra money, about $3 million to $4 million, will come from a contingency fund and is not expected to increase the project's overall cost, said Henry Nutbrown, the Port Authority's manager of engineering and construction.Cement is being used as a grout to create a shaft of fortified soil at the start and end of the project.Workers encountered looser soil than expected, requiring more cement to fill in the spaces in the gravel and silt mixture.After the shafts are built, a tunnel-boring machine will drill about 20 feet below the river.The Port Authority may ask the project's general contractor, DMJM Harris, to share the costs, contending some soil samples were inaccurate.A DMJM Harris spokesman said it was analyzing the test borings and would not comment further until the work is done. Related Links: More Allegheny County NewsGet RSS Headlines | Free Desktop Alert Copyright 2007 by ThePittsburghChannel. All rights reserved. This material may not be published, broadcast, rewritten or redistributed. The Associated Press contributed to this report. |
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