What's behind the newfound urgency in restoring roadway infrastructure?
How is it decided that a heavily damaged, three-span interstate bridge can be completely rebuilt in 47 days?
Or, how does a state highway department get away with closing 5 1/2 miles of heavily traveled interstate completely for two consecutive weekends to speed up a repavement project and then get praised by the traveling public for doing so?
And how did the urban interstate bridge that suddenly and mysteriously cracked during the middle of winter get rebuilt in a little under seven months?
What made all of this happen, in an industry known for schedule overruns and multi-year construction projects?
Nowadays, the huge increases in traffic demand that damaged or destroyed infrastructure be back at work in the shortest possible time. And the time lost while repairing a bridge or highway represents real money; in some cases millions of dollars a day while the structure is out of commission. These factors have ushered in the age of accelerated reconstruction of damaged or destroyed pieces of America's infrastructure. So what's making all of this possible?
It's a whole new way of looking at highway reconstruction, ranging from the use of design-build contracting techniques to innovative financing that makes funds available faster to using newer construction methods and materials that speed up the completion of the project. In one case, it was simply a matter of improving communications.
But the glue that is making the whole thing work is the close partnerships and working relations that the states, communities, contractors and the federal government have forged. And some of the initiative has come from the Federal Highway Administration (FHWA) in its role as a pioneer in transportation, breaking the mold and promoting business not as usual.
In the last few years this has all come together, resulting in the record restoration times of structures. Workshops have been held around the country to document and inform the highway community of the logistics and mechanics of all this information.
Here's how three different state highway departments dealt with three different infrastructure reconstruction problems, each with it's own peculiar circumstances; one a vital commercial interstate link, the second with a potentially large public relations problem and the third dependent on the successful identification of structural failure.
A classic example of bypassing the normal bureaucratic way of doing things occurred when a bridge on I-40 in Oklahoma was destroyed in May of 2002 by a string of barges that had drifted off course on the Arkansas River. Fourteen people lost their lives in this tragedy.
Not only was there a loss in human life; there was a potential loss of $430,000 a day for the bridge's users.
I-40 is one of the transcontinental interstates that cross the country. It begins in Wilmington, N.C., and terminates in Barstow, Calif., and carries a tremendous amount of commerce and travelers; this particular bridge carried about 20,000 vehicles a day.
Within one hour of the tragedy, FHWA Oklahoma Division Administrator Walter Kudzia and his Assistant Division Administrator Lubin Quinones were on the phone with their counterparts in the Oklahoma state DOT (ODOT), discussing how they could help the state move quickly to repair the span. At the same time that morning, the ODOT Chief Engineer (Get name.) was arriving at the scene. Because of the circumstances, he stayed on for several days.
Once it was determined that the cause of the collapse was an accidental collision and not an act of terrorism, detours were established and opened so that delay to traffic was kept to a minimum.
Kudzia and Oklahoma Director of Transportation Gary Ridley then met to decide how to structure the bidding to get the bridge restored as quickly as possible.
"I pushed for A+B bidding with incentive/disincentive provisions and greatly reduced bid response times," said Kudzia. "I stressed that this was an emergency situation and normal procedures in designing and replacing the spans would not be appropriate."
The contract time, in hours, however, was determined by Ridley and his staff, using a critical path methodology.
A rare prebid meeting was held just a week or so after the collapse at the bridge site so potential contractors could see the extent of the damage. At the same time, ODOTdecided to tap funds normally only available for scheduled and approved projects to get the demolition and construction underway immediately. They would be replaced later with emergency funds, which take longer to make their way through the bureaucracy.
FHWA's Kudzia concurred.
A contract was let to design the new spans at the same time demolition of the damaged spans was taking place. The contract called for the design to be complete in 16 days; it was actually completed in 12 days.
A short list of qualified bidders was drawn up and the bidders were given just four days to return their bids; the normal time for returning bids would have been 21 days. At the end of the four-day period, the bids were opened, the low-bidder selected and the recommendation made to the Oklahoma Transportation Commission, who approved it the same day.
In other words, in less time than it would have normally taken to put a project out for bid, wait the 21 days to receive the bids, select the winner and award the contract, the I-40 bridge project was designed, the damaged structure removed and a contract for its replacement awarded. Total elapsed time: 18 days.
While the project was completed ahead of schedule, the contractor was sufficiently motivated to do so. His reward was $1.5 million in incentives. But it was the intense and in-depth relations between the governmental agencies and the contractor which made the project happen.
Shut it all down
How can closing an interstate be justified in the face of a daily traffic count in excess of 85,000 vehicles?
The answer is obvious, when the alternatives to accomplishing this repaving project add up to more inconvenience to motorists and neighboring communities, numerous safety concerns and significant negative emergency response and economic and transit impacts.
This was the dilemma facing the Washington Department of Transportation (WSDOT) when they addressed the repaving of a 5 1/2 mile section of busy I-405. Busy is the right word for this section of the highway; it is the main north-south bypass around Seattle.
It all started two years prior to the actual paving operation, in 1995, when WSDOT staff met with municipal officials of the cities that were adjacent to the section that needed to be repaved. The staff presented officials with a matrix that described several different approaches to accomplishing the work, including one that had the work being done during nighttime hours, an approach that would have taken an entire construction season. Other options included day work and partial weekend closures. The approach that made the most sense from being least intrusive on the motoring public and the neighborhood communities was a total freeway closure over two weekends.
This approach offered several additional advantages:
_It was the least expensive;
_It offered the best possible finished product in terms of quality; and
_It promised motorist and worker safety.
But the prospect of closing the interstate, even at nights on weekends, posed a huge public relations problem, both for WSDOT and the neighboring community populations. It was decided to employ every possible means of communications to let everyone know what was going to happen.
For its part, the local media were very supportive by providing detailed information to the public. WSDOT public information staff mounted a major public relations program, making the construction engineer as well as public information personnel available for interviews. But that was just the beginning. Communication and coordination continued with the local cities throughout the entire construction period. Advance notice to the media had already begun in the spring of 1997 with additional reminders given out one month before the closings. Variable message signs with detailed information on the closures were installed two weeks prior to the closures. This was followed by detailed news releases and phone calls to targeted radio and TV stations. WSDOT also provided internet postings, telephone hotlines, community fliers and various other communications methods.
Two weekends were selected in August, the month when the weather is driest. An eight-mile section of southbound I-405 was closed from 8 p.m. Friday night until 5 a.m. the following Monday. The process was repeated the following weekend with the northbound section.
In spite of the potential for massive disruption, the freeway closures and construction work went well. The contractor met all schedule and quality expectations. The partnering work with the contractor was important to ensure all issues were addressed and resolved in advance. Particularly crucial was the haul route, which the contractor innovatively reduced by arranging with the Boeing Co. to temporarily lease a nearby parking lot to stockpile material and set up a portable hot-mix asphalt plant. The proximity of the plant was an enormous benefit.
An unexpected benefit came out of the project; increased productivity. Production rates for applying hot-mix asphalt averaged 350 tons/hour as compared to a normal 205-313 tons per hour for night paving on comparable projects.
The City of Milwaukee, Wis., is used to cold temperatures. So when the temperature dropped to 4 degrees below zero on the morning of Dec. 13, 2000, most folks went about their business as usual.
Except those who were driving across the Hoan bridge, on their way to work. Just before the rush hour, a 100-200-ft section of the bridgecracked from top to bottom, causing a sag in the northbound lanes about 200 ft from the bridge's edge. One person, who was on his way to his job at about 6:30 a.m., said that he noticed the sudden sagging a little bit. "It felt a little different. I thought maybe there was a pothole forming," he observed.
The bridge was once dubbed the "Bridge to Nowhere" because even though the structure connected the lakefront's north shore with its south shore, it fell far short of its envisioned use. But on that day, the bridge was carrying in upwards of 37,000 vehicles a day. Experts predicted it would take over a year to repair. One local official said that was far too long, claiming that the bridge is a lifeline to local communities.
So the urgency of getting the bridge back to working order was established. But that couldn't happen until the reason for the failure was established.
"Was it the Welding? Was it the Steel?Was it the Cold? Was it the Traffic? Was it the Soils?" asked a headline in the Milwaukee Journal newspaper.
"The driving force that controlled this was the desire to get the bridge fixed as soon as possible," said Tom Strock, Structural Systems Engineer with the FHWA's Wisconsin Division. "We accelerated the failure analysis. We also wanted to propose an interim 'fix'; something that could possibly prevent further cracking. We called this a 'prophylactic retrofit', a procedure wherebya series of 2,000holes would be drilled in the surviving beams. The holes would prevent the spreading of any subsequent cracks developing."
A contractor was selected and the work was performed on Jan. 16, 2001. Work was accelerated so that at least two lanes on the southbound span could be opened as soon as possible.
"There was also the urgency to get the material from the failed beams into analysis to find out why they failed," continued Strock. "This had to be done so we could make sure that what we were replacing would not be subject to the same failure."
A meeting was scheduled with the Senate/House transportation committee on Jan. 18 to give them a briefing on what was being proposed. "It provided the local government folks an opportunity to tell the legislators how important the bridge was to the well-being ofMilwaukee and the surrounding areas. Eventually, they went along with our recommendations," Strock added.
Unfortunately, during the course of the hearing, another crack appeared, this one about 7 ft long. As approval for the retrofit had already been cleared a plate was bolted over the newly formed crack. "As luck would have it, during the bolt-on process another crack appeared, sounding like an explosion," commented Strock. "When we looked over to see how far the crack had spread, we saw that it been stopped by the drilled holes. In other words, our prophylactic retrofit had functioned as we predicted it would."
An additional briefing was given to the Governor and the Secretary of Transportation on Feb. 16 to describe how the retrofit had worked. Everyone now agreed that the south span was probably safe for limited, low-speed passage. Accordingly, on Feb. 17, the south span was open for two-way traffic. A four-ton limit on vehicle weight was imposed and trucks were prohibited. All of these restrictions were precautionary in nature; no one felt that the span was unsafe.
Meanwhile, the analysis had proceeded, but initially it started off on a wrong supposition--that the problem was one of fatigue. There were several groups involved in the analysis; FHWA's own Turner Fairbank Highway Research Center, WisDOT, Lichtenstein Engineering, Lehigh University, Northwestern University and Michigan Tech University.
Prior to the completion of the failure analysis, WisDOT district engineers set upon a separate course to develop plans for a total replacement of the three girder spans of the bridge, estimated to cost $40 million. "They even went ahead and selected a consultant to design the new span," added Strock. "We urged them to hold off until the analysis was complete and they agreed to wait."
The failure analysis focused on the global and localized structure load paths and stress, extensive material properties testing and detailed microscopic examination of the failure surfaces. The material properties exceeded the requirements at the time the bridge was constructed and most would meet current requirements. Therefore, the failure could not be attributed to poor material. The findings of the failure analysis pointed to the geometric configuration of the web, vertical stiffener and horizontal shelf plates creating a zone of stress concentration and triaxeal constraint to a very localized portion of the web plate. This combination of effects resulted in a condition were the web was not physically able to yield under high stress and initiated a brittle fracture from an uninspectable microscopic flaw. This is the first time that this failure mode has been documented in a bridge failure.
Once the failure mode was understood, the solution to retrofit the remaining bridge became rather apparent. The structural analysis showed that the bridge could be modified to function safely without the lower lateral bracing connected to the horizontal shelf plate. The removal of these items would eliminate both the stress concentration and the constraint conditions which contributed to the failure. After receiving approval from upper management, retrofit plans were prepared and a retrofit contract was authorized using Advanced Construction (AC) funds. All this happened in just 16 days from the agreement on the failure mode. The use of AC funds allowed the project to proceed without delay of trying to identify additional funding sources. The final retrofit project restored the bridge to full unrestricted traffic on Oct. 11, 2001, at a cost of just $7.5 million. This effort resulted in a substantial savings in both time and money over the total replacement solution.
On March 25, 2002, U.S. DOT Transportation Secretary Norm Mineta presented a symbolic $12 million check to Gov. Scott McCallum to help offset the total cost of the Hoan Bridge failure. Mineta's presentation, which took place overlooking the Hoan Bridge, was a fitting tribute towards the exemplary teamwork of everyone involved with and affected by the unexpected failure of the bridge on Dec. 13, 2000.
Fastest way to go
The above three accelerated construction projects are just representative of this trend that is occurring across the country. For example, accelerated paving projects that usually allow a total closing of the section of highway to be repaved/rebuilt/rehabilitated have been successfully completed in Detroit, Mich., Wilmington, Del., Louisville, Ky., Portland, Ore., and Columbus, Ohio. In the Columbus project, the section of I-670 to be rebuilt expanded the road from four to eight lanes and reduced construction time from four years to 18 months.
Of the wisdom of shutting down this entire section of I-670, Gordon Proctor, director of the Ohio Department of Transportation said, "Under the appropriate conditions, a full closure can be an effective way to complete projects faster and improve highway safety for highway workers and motorists."
And in Birmingham, Ala., in January of 2002, a tanker truck struck a bridge support at the junction of I-65/20-59, a critical juncture that carries about 140,000 vehicles a day. While this interstate intersection was out of commission it was costing the state at least $100,000 a day in user costs. Through an extraordinary partnership between the state DOT, the FHWA and the contractor, the bridge was able to be replaced just 53 days after the crash occurred.
It does appear that accelerated construction is here to stay.
Using innovative techniques and creative thinking, the accelerated construction approach has proven to be a viable solution for the construction of today's complex, multiphase urban projects. States like Indiana and Pennsylvania have already benefited from employing this concept. A number of other states have recognized its potential as well and are preparing to employ it in the near future. FHWA and the Technology Implementation Group of the American Association of State Highway & Transportation Officials (AASHTO) have unified efforts to advocate and promote the accelerated construction approach. For more information on the FHWA/AASHTO Accelerated Construction Program, please call Dan Sanayi at 202/493-0551; e-mail: [email protected],or Jim Sorenson at 202/366-1333; e-mail: [email protected].