Source: http://enr.construction.com, June 12, 2006
By: Bill Chastain
With joy and relief, the contractor on Tampa’s Lee Roy Selmon Crosstown Expressway is set to complete the elevated portion in August, a year after the original date. Despite many setbacks, including an ongoing lawsuit, officials say the high-tech reversible lane toll road will fulfill technical expectations.
PCL Civil Constructors, a division of Edmonton-based PCL Enterprises, in April placed the 3,032nd and final segment of the 29,000-ft-long elevated portion—a big milestone for an ambitious but troubled project.
Initially, the project had a price tag of $372 million and a July 2005 completion date. Heavy commuter traffic on 9 miles between downtown Tampa and the eastern suburb of Brandon made the innovative toll road, designed by Tallahassee-based Figg Engineering Group, an attractive solution.
Then came the problems. One pier sank 11 ft in April 2004 and another sank slightly three months later (ENR 12/20/04 p. 17). Pat McCue, director for owner Tampa-Hillsborough County Expressway Authority, was fired, and repairs pushed the cost to $470 million. Ardaman & Associates, Orlando, oversaw testing of the existing piers and the locations of future piers. Its calculations cited flaws in foundations designed by URS Corp., San Francisco, that overestimated the strength of the limestone layer supporting the piers and the depths needed for test bores.
The authority has sued URS Corp. for at least $120 million. Figg also is listed in the civil suit. Under court orders, all parties will resume mediation in July.
Repairs have been made to 155 of the 224 piers. Sixty-eight piers received reinforcements, where a pair of 48-in. sister shafts were placed adjacent to the originally designed shaft. A second solution called for a series of micro piles to be drilled around existing shafts to create a stronger foundation.
“If we felt as though the original 6-ft drilled shaft was deficient in its ability to carry basic loads when the bridge was constructed on top of it, we would make that repair with sister shafts,” says Ralph Mervine, now executive director of the Tampa-Hillsborough County Expressway Authority. “If we felt as though the original 6-ft shaft was deficient only in safety factor, then we would make up that difference in micro piles.”
PCL, whose workers endured public scrutiny and “guilt by association” with the project, completed repairs by working 24 hours a day, six days a week. Its $145-million contract to build the superstructure was not affected by the lawsuit.
“I guess the thing we were happiest about is we were able to weather the finger-pointing,” says Jerry Harder, president of PCL Civil Constructors. “During the entire time we maintained our relationship with the owner. I think the most difficult thing for us was not knowing what was going to be done in terms of repairs and the length of time it took to establish a redesign. That was difficult because we had people on standby.”
PCL now is working on finishing touches, including grinding of the deck, grooving, painting, installation of lighting and the installation of switches to direct traffic as part of the reversible lane design.
The three-lane, precast concrete elevated road is built on piers within the median of the existing expressway. It will allow for one-way traffic into the city in the mornings and one-way traffic to Brandon in the afternoon. No rights-of-way had to be obtained and existing traffic could flow during construction. The piers use just 6 ft of the 40-ft median.
Almost 200 spans of 142-ft lengths are comprised of 90-ton segments. A 250-ton crane placed segments onto a custom-fabricated truss for final erection. Hollow cores within the segments contain sensors facilitating intelligent highway systems.
“Most everyone is looking beyond the design problem and [is] more interested in the functionality of the reverse lane now,” says Mervine. “We’ve had visits from several cities interested in this.”