his is the first of a series about the five finalists for ASCE’s Outstanding Civil Engineering Achievement (OCEA) awards. Established in 1960, the OCEA Award recognizes a project that makes a significant contribution to both the civil engineering profession and society as a whole. The winner of this year’s OCEA award will be announced at ASCE’s Outstanding Projects And Leaders (OPAL) Gala, March 20, at the Renaissance Arlington Capital View Hotel in Arlington, Virginia. Today, read about the I-15 Corridor Expansion project.
I-15 Corridor Expansion Project
Like many interstates in the U.S., Interstate 15 in Utah County, Utah, had reached the end of its design life. The infrastructure was deteriorating and needed to be updated; congestion and population growth in the area demanded the freeway be widened.
The Utah Department of Transportation’s (UDOT) $1.725 billion I-15 Corridor Expansion (I-15 CORE) project used innovative procurement, scheduling, and planning techniques to complete the highway expansion project 2 years ahead of schedule while saving taxpayers $260 million. The expanded roadway relieves congestion for motorists who travel to and from Salt Lake City and Provo. By using accelerated bridge construction, wireless paving and grading, and diverging diamond interchanges, the impact to traffic was reduced for the over 130,000 motorists traveling through the I-15 CORE every day.
ASCE News Associate Editor Doug Scott interviewed Brian G. Tolbert, P.E., project manager/infrastructure with the Fluor Corporation, who served as deputy project director of the I-15 CORE project.
1. What is the most innovative or creative aspect of your project?
Accelerated Bridge Construction (ABC) is not entirely new to UDOT projects, on a singular basis. However, PRC [Provo River Contractors, a joint venture of Fluor, Ames Construction, Ralph L. Wadsworth Construction, and Wadsworth Brothers Construction] moved 5 bridges into place using ABC methods over the course of the I-15 CORE project. In particular, our team set a Western Hemisphere record for moving the Sam White Bridge via self-propelled modular transport (SPMT), the longest completed bridge structure and the longest continuous 2-span bridge structure. This bridge is 354 feet long and 80 feet wide, and was coined the “Super Bowl” of bridge moves due to its football-field size and the fact [that] it was moved around the time of the NFL Super Bowl. The Sam White Bridge was only the second multispan bridge structure moved in the Western Hemisphere. The first multispan moved by SPMT was the 200 South bridge, which was moved into place by PRC the prior weekend. The use of large-scale wireless paving was another innovative aspect of this project. The use of cloud computing allowed up-to-date design information to be available nearly real-time for this GPS-guided system.
2. What was the biggest challenge?
Constructing the largest transportation project in Utah history, faster than any other megaproject, while maintaining all existing lanes of traffic, was the biggest challenge. Essentially, the entire 24-mile stretch was under construction at the same time. Coordinating all of the construction activities, including traffic lane shifts and effective public outreach, was a significant challenge, too. Maintaining the safety of our workers exposed to high levels of traffic adjacent to work zones was also a major issue during construction.
3. Did your project have any technical issues that you had to overcome? If so, what were they and how did you overcome them?
The entire project area is ancient lake bed. This results in soils that aren’t ideal for construction, particularly when accelerating the project to a record pace. Perhaps the most time-consuming technical issue to resolve relates to the poor subsurface conditions near Utah Lake that affectan approximate 3-mile stretch of the interstate. The proposed design contemplated raising this section of roadway along the lake by approximately 5 feet to exceed the 100-year flood plain elevation. However, this amount of embankment was predicted to induce long-term settlements that would have lasted for years and resulted in significant settlement amounts – up to 2 feet. PRC and UDOT overcame this issue by redesigning the interstate vertical profile to reduce the embankment-inducing settlement, while also designing and constructing earthen berms along the lake border to provide a dam effect and keep the interstate from being submerged in flood events. Also, highway detention areas in the highway alignment were constructed that would function in the event [that] the 100-year flood occurred.
4. What time and budget challenges did your project have and what did you do to overcome them?
The extremely short construction schedule was the biggest challenge on the project. We had less than 3 years to design and build a $1.1 billion interstate freeway. We brought in 3 of the industry leaders to complete the design using over 300 design engineers in only 14 months. These firms were HDR, Michael Baker, and Jacobs. During the construction phase our team worked double shifts six days [a] week. We also came up with innovative techniques for cold-weather concrete paving and MOT [Maintenance of Traffic] shifts to help facilitate the schedule.
5. Sustainability is one the three initiatives here at ASCE. Describe how your project adheres to being sustainable.
Our project recycled a large majority of the pavement and base materials that were demolished by the project. Instead of going to landfills or other disposal sites, this material was crushed into useable size and composition for embankment and pavement base materials. Slag, a by-product of steel processing, was used extensively throughout the project, which reduced the need for excavation of other sources. A secondary sustainability benefit was the reduction in traffic congestion and delay [through] utilizing innovative MOT strategies that maintained the existing number of lanes open to traffic throughout 90% of the construction schedule. UDOT estimates this reduction in congestion provided over $800 million in user-cost savings.
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