Chicago's good vibrations

After nearly 30 years of tunnelling works for the Chicago Tunnel and Reservoir Plan (TARP), a local politician has been calling for the project to be shutdown before it is even completed.

Ronald Waters, an elected official of the City of Harvey, has been calling for a cease-and-desist order to be served on the joint venture contractors Jay Dee/Affholder amid claims that blasting operations for the project were causing damage to pipes and the foundations of nearby residences.

The works in question are on the 12.4km Little Calumet leg that, when commissioned, will complete the 176km deep tunnel system as part of TARP. This US$167M contract was awarded to the joint venture in January 2002 for the main 5.5m diameter tunnel, smaller collector tunnels, nine drop shafts, over 7,000m of pipeline and a launch shaft. Affholder was primarily involved on the main tunnel, which was driven through limestone using a Robbins TBM. Jay Dee was responsible for the collector tunnels as well as the drop shafts. Three shafts were in close proximity to the City of Harvey, meaning residents became aware of blasting from three sites instead of one.

The joint venture has stated that the blasts are not the cause of damage and that it monitors every blast with seismographs, saying all blasts have been below the contractual lower limit. A pre-blast survey was also undertaken for all structures within 150m of any blast.

Gregory Hauser, project manager for the JV, said the seismographs were leased from a specialist who calibrates the equipment monthly, as well as reviewing the data to prepare a report and analysis.

In addition, he said they had engaged two different firms of structural engineers to inspect and asses the alleged damage. Speaking at the end of March, Hauser said, "to date there is no evidence that the damage claimed is in any manner connected to the construction or the blasting." In response to the clamour for a cease-and-desist order, Hauser said he was unaware of any grounds on which such an order could be served, as all permits were in place and agreements were being adhered to.

About 130 residents are believed to have reported varying degrees of damage, all from the same general area around the three shaft sites. Hauser said there was a procedure for sending claims that had been denied by the JV to binding arbitration and only five such claims were at that stage of resolution.