|Concrete overlay work on middle lane of westbound bridge. (Photo courtesy of Cianbro Corp.)|
Cianbro Corp., the contractor on a problematic Chesapeake Bay Bridge concrete repaving project, has provided detailed comments to back up its contention that it adhered to specifications and procedures approved by the Maryland Transportation Authority, the bridge's owner. For example, the Pittsfield, Maine-based company said, it repeatedly told the authority that the specified matrix restorer was breaking the overlay bond, not restoring it.
Delamination on parts of the repaved deck caused the state to have Cianbro redo a large portion of the overlay work and prompted state Transportation Secretary Robert L. Flanagan to bring in an outside review panel to determine what caused the problem. Flanagan also is restudying a planned second phase of the bridge project, which will delay its completion date for months.
The panel's report, released Feb. 10, didn't assess blame, but cited several factors that led to the overlay failure, including the bridge's thin deck, inadequate preparation of the substrate surface, use of an epoxy matrix restorer, silica-fume concrete mixtures and a sprayed-on curing compound, as well as placing concrete in cold temperatures.
In comments when the problem became public last September and after the review panel's report was issued, Cianbro officials said they had done the work according to project specs and the state agency's direction. At a Feb. 17 press conference at Cianbro's Baltimore office, Mike Hart, Mid-Atlantic regional vice president for the company, said "In general, we agree with the report," but added that Cianbro thinks it is "very important to clarify some issues" in that document.
Hart went through the six factors outlined by the panel, which was led by former Transportation Research Board Executive Director Thomas B. Deen. In one key point, Hart said that in January 2002, even before the overlay work began, Cianbro and its subcontractor, Pioneer Contracting Co., Odenton, Md., told the state authority that the matrix restoring agent was inappropriate for the job. "It was acting as a bond breaker and not a bond restorer," Hart said.
He added that after Cianbro repeated its views on the material over several months, the authority agreed to have core samples done to see if the restorer was working. In May 2003, Cianbro said the authority directed it to stop using the compound because the tests backed up the company's position.
Regarding the substrate surface preparation, Hart said Cianbro found it was encountering the top mat of reinforcing steel at a 1.5-inch depth, though the contract documents called for removing 2 inches of concrete. The state agency then changed the specs to remove only 1.5 in. so the steel wouldn't be harmed, he said.
Concerning the type of concrete mixture used, Hart said Maryland state agencies approved and modified the silica-fume mix design and added that the company provided concrete mixtures that conformed to the specifications of the contract and were approved by the MdTA."
Hart also said that the agency changed the minimum temperature benchmark for placing the overlay from 45 to 35 degrees in February 2003. He added, "All temperatures at the time of concrete placement were within the contract specifications and were specifically approved by MdTA's representatives on site at the time of placement."
Regarding curing methods, Hart said the state authority approved all such work on the project.
Asked whether he thought the specifications were flawed, Hart said, "I'm not going to comment on that."
When the review panel's report was released, Flanagan said that its members weren't charged with assessing blame for the problems. He added that the state attorney general's office would deal with "allocation of responsibility."
The project involved a combination of new concrete overlay and full-depth replacement of sections of the four-mile-long, three-lane westbound bridge, which was finished in 1973. It is parallel to a 53-year-old eastbound bridge.
Cianbro was the only bidder on the first phase, awarded in 2001 and initially valued at $33.5 million. It called for overlays on 95 spans totaling more than 12,500 ft. and deck replacement on 21 spans stretching for 3,900 ft. The contract later was increased by $10 million and the overlay that had to be redone will cost an additional $7 million. Gary Gorman, Cianbro's project manager, said the overlay encompassed 12,584 ft. on each of three lanes. Of that 37,750 lane-feet, about 22,600 ft. have been or will be redone.
Hart said Cianbro was the sole bidder on phase two, which was to cover work on 6,700 ft. and eight spans of the bridge. He declined to say what price the company bid, but said he had heard orally from the Maryland Transportation Authority that the bid probably would be rejected.
The Maryland DOT did not return a call requesting comment by enr.com's deadline, But Flanagan was quoted by the Baltimore Sun as confirming that the state won't award the phase-two contract, though adding that Cianbro is "fully qualified to do the work out there." Flanagan, who also chairs the transportation authority, which is a unit of the state DOT, said he decided to change the parameters of phase two following recommendations of the review panel.