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Publication Number: FHWA-HRT-07-015
Date: July 2007
When a gasoline tanker truck crashed and exploded into flames on the San Francisco Bay Area's most heavily traveled freeway interchange in the early morning hours of Sunday, April 29, 2007, the outlook seemed bleak for area residents and commuters. A portion of the I-80 eastbound to I-580 eastbound connector road collapsed onto the connector road between westbound I-80 and southbound I-880, closing two integral parts of the interchange known as "The Maze," which carried some 80,000 vehicles a day. The local media predicted months of gridlock, detours, and misery for drivers. Instead, in just over 1 week the roadway's damaged lower deck was reopened to traffic. And in less than a month, the upper deck was also back in business. How did the California Department of Transportation (Caltrans) and its contractors beat expectations and get traffic flowing again on this vital interchange? "The rapid repair was a combination of ingenuity, teamwork, and old-fashioned hard work," says Randell Iwasaki, Chief Deputy Director of Caltrans.
Within minutes of the accident, Caltrans and the California Highway Patrol had closed the damaged sections. Temporary detour signs were set up, and Caltrans activated its Emergency Operations Center. A proclamation issued by Governor Arnold Schwarzenegger permitted Caltrans to award emergency contracts. One of Caltrans' first steps in accelerating the repair process was to hire a demolition contractor, Cleveland Wrecking Company, which was at work on the day of the accident on a project just across the bay in San Francisco. Within minutes of Caltrans awarding a contract on April 29, Cleveland Wrecking took crews and equipment from its San Francisco project and sent them over to the Maze to begin removing the collapsed section of the roadway.
Meanwhile, staff from across Caltrans worked to expedite the design and reconstruction of the I-880 and I-580 connectors and coordinated with representatives from the City of Oakland to organize traffic control and plan detours on city streets. To encourage the use of public transportation, the State declared a "free transit day" on Monday, April 30. Buses, trains, and ferries ran at full capacity on the 30th, while commuters who did not use public transit altered their regular routes and stayed away from the Maze. Despite the dire predictions, the expected gridlock failed to materialize.
|A gasoline tanker truck explosion on April 29, 2007, closed two integral parts of the San Francisco, CA, interchange known as "The Maze."|
Once the debris was cleared, steel and concrete samples were taken from the I-880 connector ramp for testing and evaluation. The tests showed that while the fire had warped and twisted the I-880 girders, the structural integrity had not been compromised and the girders could be straightened. The concrete deck was also repairable. After installing falsework to support the freeway, Caltrans and its contractor, American Civil Constructors, used hydraulic jacks to lift the entire structure 23 cm (9 in) and bring the roadway back into alignment, as the warped girders had resulted in a dropoff between sections. Once the deck was realigned, the damaged concrete, barriers, and electrical components were replaced. Meanwhile, work began on fixing the girders by using a heat straightening process. The falsework assumed most of the structural load, allowing the ramp to be reopened to traffic on May 8 while workers continued the heat straightening. On the same day, Caltrans awarded the contract to rebuild the I-580 connector ramp to C.C. Myers, Inc., of Rancho Cordova, California. Nine contractors had been invited to place bids on this emergency project, with seven ultimately submitting bids. C.C. Myers had the lowest bid of the seven. Myers' extensive experience with accelerated projects included the reconstruction of I-10 following the 1994 Northridge earthquake in Los Angeles.
|"This was a team effort. Our subcontractors did a fantastic job. When the owner, the contractor, and the subcontractors all work off the same page, it shows what you can accomplish."|
The Caltrans contract called for a milestone of opening the roadway in 50 days. While the contract was bid at just $867,075, for every day the project finished earlier than 50 days, the contractor would earn a bonus of $200,000, with a cap of $5 million. A $200,000 daily penalty would be assessed if the milestone was not met. Less than an hour after the contract was signed on May 8, Myers' staff was on site and ready to start work. Myers also quickly hired Con-Fab of Lathrop, California, to build a new bent cap and Stinger Welding of Coolidge, Arizona, to build the new girders. Stinger contacted specialty steel mills in Sewickley, Pennsylvania, and Houston, Texas, and within just a few days the steel was on its way to Arizona for fabrication. To drastically cut the delivery time, Myers had Stinger hire two truck drivers for each rig hauling the steel. Caltrans helped to speed up the fabrication process by sending engineers and inspectors to Arizona to assist with and monitor the fabrication and be available to answer any questions immediately. Caltrans also provided the shop drawings to both Con-Fab and Stinger within 24 hours of the contract award.
|A portion of the I-80 eastbound to I-580 eastbound connector road collapsed onto the connector road between westbound I-80 and southbound I-880.|
|New girders are installed on the I-580 ramp.|
"This project was all about partnerships and also minute by minute, hour by hour daily planning," says Dan Himick, President of C.C. Myers.
"When we all focus and come to the table with the same goal, we can get things done quickly," adds Gene Fong, Division Administrator for the Federal Highway Administration's (FHWA) California Division office. "The results far exceeded expectations." FHWA's Division office held daily meetings during the reconstruction to talk about the status of the project and help coordinate its partnering role with Caltrans. The work contracted met all Federal and State contract requirements.
The 17-m (55-ft) long, 120-ton bent cap was ready for delivery on May 15. A 30-axle tractor trailer rig hauled it from Lathrop to Oakland, closely followed by the local news media. As news helicopters hovered overhead, cranes lifted the bent cap off the truck and set it atop the columns. It was a perfect fit. On May 16, the first two new girders were smoothly lifted into place. Over the next several nights, the rest of the girders were trucked to Oakland, with the last two girders installed in the early morning hours of May 20. With two crews working 12-hour shifts, the diaphragms and wood deck forms were added as soon as the first girders were installed. Once the wood forms were ready, additional workers were brought in to start assembling the rebar. This process continued as the rest of the new girders were brought in. Once the last of the new girders were installed on May 20, it took only a short time to add the additional forms and remaining rebar. That afternoon, the new deck was ready to pour.
|Concrete is poured for the new I-580 connector ramp.|
|The I-880 ramp reopened to traffic on May 8, 2007.|
|The first vehicles traveled across the new I-580 ramp on May 24, 2007, beating all predictions.|
Myers and Caltrans used high early strength concrete for the new deck. After placing the concrete, water hoses were used to regularly moisten the curing blanket to keep the concrete from drying too quickly. Assuring a moist cure increased the concrete's strength. While the concrete cured, workers finished fixing the barrier rails, replacing the damaged electrical wiring and hardware, and cleaning up the work site. Caltrans had announced that the road would reopen sometime before the morning commute on Friday, May 25. Instead of holding a ceremony, everyone from the Governor on down agreed that the road would reopen as soon as it was ready, without causing any further delay to commuters. At 8:40 p.m. on Thursday, May 24, the first vehicles traveled across the new ramp, beating all predictions. As the San Francisco Chronicle declared in its headline the next morning, "A-Maze-ing!"
Finishing well ahead of the 50-day milestone, C.C. Myers earned the maximum bonus amount. "This was a team effort," says Himick. "Our subcontractors did a fantastic job. When the owner, the contractor, and the subcontractors all work off the same page, it shows what you can accomplish."
"All involved sought creative and innovative methods to cut the construction time without compromising quality," adds Iwasaki. "Almost from the first moment, Caltrans and its contractors were determined to turn a horrific accident into the project of a lifetime, something in which everyone could take pride."
To learn more about the Maze reconstruction project, contact Randell Iwasaki at Caltrans, 916-654-5791 (email: email@example.com).
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