Much to the dismay of long-suffering commuters, the fresh pavement on Interstate 40 in Durham that was finished just last winter has begun to crumble. After several years of construction-related traffic congestion, the barrels, cones and concrete barriers will have to be trotted back out for another interminable period.
The probable source of the pavement breakdown has already been identified and reported, both by DOT and Applied Pavement Technology, a consultant hired to assess the problems. The project expanded I-40 from four to six lanes, with one new 14.5-inch-thick lane in each direction where the grassy median had been. The existing 11.5-inch lanes were topped with three inches of new concrete in a process called "bonded overlay," in which the new concrete is essentially laminated to the old. As with many highway paving projects, the old lanes had been sawed across at approximately 20-foot intervals to allow for expansion and contraction without buckling or cracking. As has been well documented in industry literature, the overlay should have been sawed completely through and the cuts located directly above the original pavement joints so the slabs would move together in the heat and cold.
Instead, as tests have confirmed, the contractor did not cut the full three inches through the overlay in most places, nor were the cuts properly aligned with those in the old pavement. When the bottom layer expanded and contracted as the weather changed, the pressure on the top layer caused it to crack, crumble and become unglued.
DOT officials initially announced they would seek repairs free of charge from the contractor, Granite Construction of California. But the consultant's report noted that the project plans did not include any drawings or specifications for the depth or location of the saw cuts; a Granite engineer told The News & Observer that the specs had called for a 1.5 inch cut, half the necessary depth. In either case, the fault would appear to lie with DOT rather than Granite.
But DOT's glaring screw-up with the plans is only the beginning of the story, and questions about the I-40 project (and others) need to be raised--if not by DOT in its internal investigation, then by someone else.
The consultant's report notes several issues with the inspection of the project. Inspectors are supposed to check the work of the contractor and conduct tests on a daily basis to ensure that the construction is going according to plan. But the inspections were apparently lacking in some critical areas. "Verifying sawcut depth is a routine and very necessary field inspection activity for all concrete pavement construction projects, whether they be new construction or resurfacing," the report states. "There is no record of any joint sawcut depth measurements being made in the field during construction for the bonded overlay."
Moreover, bond strength test data showed unusual variability and "raise a concern about the accuracy of testing," according to the report. The strength testing was supposed to have been done 14 days after the concrete was poured, but was instead done at different intervals. Evidence indicates that "the existing pavement surface preparation may not have been performed as required on a consistent basis," according to the report, and rough patches on the overlay surface that should have been caught by inspectors were bad enough that DOT started making repairs on them in July.
While DOT has about 900 inspectors on staff in its Highway Division, inspection services for the I-40 project were contracted out to HNTB, a large transportation infrastructure firm with 60 offices nationwide. HNTB is one of six companies with an open-ended contract to perform construction and engineering services for DOT on an as-needed basis. One might think that a project of the magnitude and import of the I-40 widening would have been a candidate for in-house inspections, but DOT spokesman Ernie Seneca says that private contractors are hired whenever DOT personnel are tied up with other ongoing projects, which was the case with I-40. "It's a workload issue," Seneca says.
Just what HNTB did on the job is unclear, because DOT is shielding HNTB's inspection diaries from public view. DOT has the option to withhold the diaries under the open-records statute, says Seneca, though he will not say why the agency is refusing to release the records beyond the fact that it's legal. The records may not contain anything incriminating, but hiding them only fuels suspicion to the contrary.
HNTB spokeswoman Barbara Pruitt acknowledged that the company was involved in the project, but in a minimal way. "We furnished inspectors to DOT, who then managed those inspectors," Pruitt says. "Beyond that, we were not on-site involved in it." Pruitt referred further questions back to DOT.
Asked to detail DOT's oversight role when private firms perform services that are often done in-house, Seneca has little to offer beyond saying that the Division Engineer is responsible for the administration of contracts, and that the Resident Engineer for the project has general oversight responsibility. It shouldn't be that difficult to determine if DOT routinely conducts spot inspections of its own, or reviews the daily diaries, or otherwise has procedures in place to make sure that contractors are doing what they're supposed to do. Whatever happened on I-40, the lack of internal oversight meant that design, construction and inspection errors were not caught until it was too late.
Seneca says that DOT will review the consultant's report and continue the investigation to its completion, though "responsibility is one of the key things that has not been determined at this juncture." At the very least, this should mean that several individuals will be fingered for shirking their duties and punished accordingly.
But disciplining a couple of lower-level bureaucrats--who may only have been doing what they've always done or been told to do, after all--won't address the systemic ills that the report and other information suggest may be at the core of the I-40 mess. If I-40 was plagued by a series of mistakes that were not caught, it would be ludicrous to believe that other projects have not suffered from the same deficiencies, even if the results aren't as dramatic. "If this is the way that business is being done, then it's a problem that has to be directly addressed," says Board of Transportation member Ken Spaulding, whose district includes the project. "Unless you change the process, then once the spotlight is off [the bad I-40 pavement], you go back to business as usual and problems as usual."
Repairs to I-40 are already under way. The consultant recommended grinding away the I-40 overlay and replacing it with a more traditional asphalt, a solution DOT is already planning to implement. But that fix only has a life span of eight to 12 years as opposed to the 20-plus years that the original design anticipated. Efforts to minimize inconvenience to the motoring public mean that much of the work will be done at night, which will increase its cost. So the highway, originally projected to cost less than $50 million, will cost millions to repair, then millions more to upgrade in a decade, possibly topping $100 million not too far down the road.
Meanwhile, opponents of the Triangle Transit Authority rail plan, already stripped to the bone, are drooling in anticipation of the prospect that the latest round of federal hoops will derail it entirely. As The N&O reported in its recent series on transit, rail projects are subject to constant ridership analyses, financial assessments and other reviews, any one of which can jeopardize federal funding. Highways, on the other hand, undergo little such scrutiny. The I-40 project stands as a metaphor for the idea that building new lanes as the sole solution to traffic congestion is a strategy doomed to cost us more than we can possibly anticipate.