Published on June 24th, 2013 | by UC&D Magazine0
For UDOT, Building Bridges is as Simple as A-B-C
By Brad Fullmer
It’s been more than 5 ½ years – October 27-28, 2007 to be exact – since the first bridge for the Utah Department of Transportation (UDOT) was rolled into place using self-propelled modular transporters (SPMTs), a project that heralded the arrival of UDOT’s Accelerated Bridge Construction (ABC) movement.
Since the time of that I-215 45th South Bridge move, UDOT has forged a reputation nationwide as the leader in ABC technology, and has moved more bridges into place via ABC methods than all other states combined, according to former UDOT Executive Director John Njord, who retired in early 2013 from the Department after more than 25 years, including 12 years as the top executive.
“I’ve gained a little perspective in the month I’ve worked as a consultant with other states across the country and their hesitance with ABC,” said Njord. “(UDOT) has done more ABC bridges than all other states combined. We learned of the technology from Florida, but have taken it to a whole new level. UDOT is committed to reducing (traffic) impacts. ABC is a tremendous method in doing just that. It’s striking to see how reluctant other states are in embracing the concept.”
According to Carmen Swanwick, Chief Structural Engineer for UDOT, by the end of August 2013, 42 total bridges in Utah will have been moved using ABC techniques, including 25 via SPMTs, 16 by lateral slide (using rollers and hydraulic jacks), and one (Layton I-15 Interchange) that was ‘launched’ into place.
There are myriad reasons for utilizing ABC, including increased safety for the contractor and public, reduced onsite construction time, reduced environmental impact, and increased constructability. Perhaps the main reason, though, is a significant reduction in mobility impacts and traffic delays.
“We consider user costs when performing our analyses. The cost savings to the public of utilizing ABC is the driving factor.” – Carmen Swanwick, UDOT Chief Structural Engineer
“We consider user costs when performing our analyses,” said Swanwick. “The contractor has an incentive to get (the project) done faster.”
“ABC is a part of what we’re trying to accomplish – it’s not the end goal,” added Carlos Braceras, a 27-year UDOT veteran who was named Executive Director in June. “The end goal is to deliver projects as quickly as possible within budget, with the least impact to the public.”
The Genesis of ABC for UDOT
While the I-215 45th South bridge is often alluded to as the beginning of the ABC movement in Utah, the reality is ABC techniques have been implemented since 2002. The program began slowly, with the utilization of precast concrete elements such as deck panels, approach slabs and abutments. After visiting Florida DOT in 2005 about ABC, UDOT officials were ready to embark on the Department’s ‘bridge move’ phase.
UDOT hired consulting engineering firm Michael Baker Jr. (Baker), a national firm with an office in Midvale, in November 2006 for the design of the I-215 45th South Bridge. According to Michael Arens, Operations Manager for Baker’s Midvale office, UDOT officials and representatives from Baker took a scanning tour to New York City in January 2007 to witness SPMTs move a bridge off barges and onto abutments over the Harlem River. The experience was invaluable.
“Even though it wasn’t an exact same type of project, it was valuable to meet with the contractor and talk about challenges they encountered and different tricks they found out during their process,” said Arens. “In addition we did a lot of research on (existing) data.”
Baker started design in March 2007, and shortly thereafter UDOT brought in Draper-based Ralph L. Wadsworth Construction (RLW) as the contractor in a CM/GC process, which was a unique project delivery method at the time. According to a September 2011 report prepared by WCEC Engineers, Inc. of Salt Lake City, the original programmed budget for the project was $6.6 million, but construction costs came in at just under $7.3 million. The savings in costs to the traveling public, however, were significant. The bridge was able to be moved into place in approximately 58 hours, requiring I-215 to be closed for less than 2 ½ days. Using UDOT’s daily traffic volumes on I-215 and 45th South from 2007, assuming a user cost of $15 per hour, the savings from ABC via SPMTs was estimated at $40 million.
“The cost savings to the public of utilizing ABC is the driving factor,” said Swanwick.
The fastest ABC bridge moves to date for UDOT was done by Wadsworth Brothers Construction (WBC) of Draper in August 2008 on four bridges on I-80 at Mountain Dell and Lambs Canyon up Parley’s Canyon near Salt Lake City. WBC replaced the four bridges in 37 hours over two weekends. The bridges were built adjacent to the existing structures in the median of I-80 over an approximate four-month period and were moved into place via SPMTs. According to the Federal Highway Administration, it was the first project in the nation to demolish, move and replace two bridge superstructures in 16 hours, and was the first total closure of a major Interstate trucking route for bridge replacement. By using off-site construction and SPMTs, UDOT estimated that motorist delay was decreased by 180,000 hours, with a user savings of more than $2.5 million. In addition, WBC’s bid of $9 million was $1.5 million less than the lowest traditional construction bid.
“The key to making that project successful was planning,” said Guy Wadsworth, President of WBC. “We planned every aspect of the job in great detail. Everything had to go as planned or chaos would have unfolded and traffic would have been backed up for 20 miles. We also learned from the first weekend closure and implemented our lessons learned to replace the second set of bridges in six hours less than the first set.”
Ralph L. Wadsworth Construction has the most experience of any Utah contractor when it comes to doing ABC projects for UDOT, with RLW having completed 34 bridge moves since October 2007, including 13 via SPMTs.
Con Wadsworth, President of RLW, said his company really earned its ABC chops on the I-80 Reconstruction project (titled ‘Innovate 80’ by UDOT) in the summer of 2008, when it constructed seven bridges at a staging area off the I-80 1300 East exit – better known as a ‘bridge farm – and moved them into place via SPMTs over a six-week period from June to August. RLW also moved an eighth bridge at I-215 and 33rd South on that same project.
“Innovate 80 set the stage for everything that’s happened since,” said Con. “We were lucky we pulled it off without a hitch. It was a hairy job, but the Layton I-15 Interchange bridge move was actually more difficult in some respects. It took us another step in ABC work that no one else had tried.”
Other DOTs Following Suit
UDOT’s most recent high-profile SPMT bridge moves occurred on the I-15 Utah County Corridor (CORE) project (completed December 2012), where four bridges were moved into place using SPMTs, including the first-ever two-span bridges – the 200 South Bridge and the Sam White Bridge – in Spring 2011. Arens said the bridges were 330 ft. and 354 ft. in length, respectively and required four lines of SPMTs. DOT officials from other states were on hand to witness the Sam White Bridge move – the largest two-span superstructure ever moved into place via SPMTs in the Western Hemisphere, adding to UDOT’s ABC lore.
The most recent bridge slide in Utah occurred at the end of May on the $5.57 million I-15; Manderfield Bridge project north of Beaver.
“It’s been very good,” Arens said of his firm’s involvement with UDOT’s ABC process. “A lot of state DOTs are interested. It’s awesome how other states are seeing UDOT as a trailblazer in figuring this out.”
Arens said he recently helped the Wisconsin DOT write the ABC portion of its bridge manual and is going to Milwaukee to provide quality assurance/oversight for WISDOT’s first ABC bridge move on June 14. In addition, Baker is under contract with the Iowa DOT to provide oversight and detail review with its first bridge move this fall.
“It’s definitely something that is growing outside of Utah,” Arens said. “Transportation officials recognize the value of it in reducing the impact on the traveling public.”
“Accelerated Bridge Construction has its uses, although it’s too expensive to implement on every bridge,” added Guy Wadsworth. “For those high-volume interchanges where long-term bridge construction would result in extensive highway user costs and delays, it pays for itself. Having a core group of experienced contractors in Utah who can perform this type of work is useful to UDOT.”
“I think it’s in the future of every state; it’s just a matter of time,” said Njord. “Here is the state of Utah, representing less than 1% of the (U.S.) population, yet we’ve delivered more ABC projects than all states combined. It’s a remarkable achievement.”