With more than 220 construction projects in progress or scheduled to start this year, the Utah Department of Transportation (UDOT) has its hands full overseeing nearly $3.3 billion in statewide infrastructure development. One key endeavor is the Blackrock Reconstructed Project, which calls for the replacement of three aging highway bridges in northwest Utah to facilitate safer, more efficient travel for commuters and freight traffic. 

Named for the historic “Black Rock” landmark, a cape on the Great Salt Lake’s southern shoreline that marks the entrance to Tooele County, the Blackrock Reconstructed Project consists of rebuilding the eastbound and westbound I-80 bridge structures crossing over Union Pacific Railroad (UPRR) tracks as well as a flyover at the intersection of SR 36 and I-80 in Lake Point. A third southbound lane is also being constructed on SR 36, between Hardy Road and Sunset Road, to prevent traffic from queuing on I-80 as a result of the signal at Saddleback Boulevard.

By incorporating innovative solutions such as bridge information modeling (BrIM) and accelerated bridge construction (ABC), UDOT is fulfilling its broader mission to meet growing transportation demands while keeping current systems running as smoothly as possible.

Utah’s Escalating Transportation Demands

Utah serves as a major crossroads for passenger and freight movement, both regionally and nationally. Approximately 196 miles of I-80 run through the northern part of the state, extending from Tooele County in the west to the I-80/U.S. 189 area in the east. 

According to UDOT’s 2019-2050 Statewide Rural Long-Range Transportation Plan (LRP), freight transport represents almost half of all vehicles traversing I-80 and I-15, another major corridor in the state. The transportation plan states further: “Utah sees significant regional and national freight traffic on its freeway routes, as goods crisscross the country and serve Utah’s local markets. Utah also contributes its own freight traffic to the national network, through the generation of food products and extraction of natural resources for energy production. In 2015, Utah carried $159 billion worth of goods in trucks on its roadways, and that number is projected to increase to $275 billion by 2045.”

The LRP also indicates that Utah is experiencing some of the highest population growth rates in the nation, particularly on the periphery of existing urban areas. This is most certainly true for Tooele County, which has strong commuting ties to the Salt Lake City metro area, according to researchers at the Kem C. Gardner Policy Institute at the University of Utah. Ranked as one of the fastest-growing areas in the United States, Tooele County appeals to many outdoor adventurers, tourists, and history enthusiasts thanks to its scenic landscape, unique attractions, and rich cultural legacy.

In addition to providing necessary design upgrades to roadway infrastructure originally built between the 1950s and 1980s, the Blackrock Reconstructed Project will help to address some of the strains on the existing system caused by population growth and freight transport. 

Key Members of the Project Team

In 2018, UDOT awarded a Construction Manager/General Contractor contract to Granite Construction Company, a nearly century-old organization headquartered in Watsonville, California. The firm has completed more than $12.5 billion in alternative procurement projects over the last two decades. According to the company’s website, its methods related to design-build, public-private partnership and CMAR/CMGC projects “lead to a more economical process, promote a collaborative design process and more buildable plans, share risk, foster innovation and address specific owner objectives.”

Two global design consultants also lent their expertise on the Blackrock Reconstruction Project: Michael Baker International, a provider of engineering and consulting services, and HDR, a firm offering engineering, architecture, environmental, and construction services. Approximately 15 subcontractors are being utilized as well, including: Harris Rebar (reinforcing steel); Utah Pacific Bridge & Steel (steel girders); OlsenBeal Associates (steel girder erection); Forterra (concrete girders and deck panels); and AAA Barricade Company (traffic control).

A Sophisticated Engineering Model

Construction on this estimated $41 million project has been underway since spring 2018. The three new bridges are engineered to meet current design standards and provide a 75-year life span. These rebuilds will require less routine maintenance and deliver smoother, more efficient traveling experiences.

Crews completed the new SR 36/I-80 flyover in September 2019, which was built approximately 3 feet from to the original bridge in order to minimize traffic impacts. The old SR 36 bridge was demolished in October 2019.

This year, workers are erecting the remaining two bridges over the railway tracks, which will be 4 feet higher than the original structures to meet current UPRR clearance standards. The westbound I-80 bridge is being built first, followed by the eastbound I-80 bridge.

With continuous improvement in mind, Granite assisted UDOT with transitioning from document-based information exchanges to integrated data models by developing BrIM standards, workflow processes, and procedures for design and construction of the replacement bridges.

“In support of UDOT’s goal to implement 3-D engineered models for construction by utilizing 3-D design tools in preconstruction, providing design files to contractors, and developing processes and procedures to advertise projects with the models as the legal document, UDOT commissioned that the three new bridges be designed and built using entirely 3-D technology,” says UDOT Project Manager John Montoya.

According to the Federal Highway Administration’s website, 3-D engineered models “are widely used by the highway community to more effectively connect a project’s design and construction phases. These models and the as-found, digital geospatial data that supports them can also be applied to other phases in the project delivery cycle to positively affect safety, project costs, contracting, maintenance, and asset management.” 

BrIM is similar to building information modeling, or BIM, in that it is a collaborative digital tool used to make more informed decisions about constructability, staging and safety throughout design and construction. One hallmark of this forward-thinking technology is its inclusion of life cycle considerations for each project component. By providing a deeper, more accurate understanding of future bridge operations, BrIM enables project owners to optimize their maintenance programs and save valuable time and resources.

Montoya adds, “What makes this innovation so highly valuable is that BrIM technology provides better accuracy in observing details that are not easily addressed in traditional plan sets. While it does actually require more upfront time than typical 2-D design, it has shown to give better direction for contractors, subs, and project team members during construction of the actual bridges.”

Temporary Bridge Keeps Traffic Moving

Because I-80 is a vital conduit between Tooele and Salt Lake counties, keeping traffic moving safely has been a central focus throughout construction. According to project officials, the heavily traveled roadway carries an average 26,000 vehicles per day.

“Any disruption to the I-80 arterial can result in hours of travel delay for commuters in the area,” Montoya says. “The solution to this challenge is the addition of a temporary bridge for eastbound I-80 traffic, allowing the contractor to shift traffic away from the westbound I-80 bridge and focus fully on construction without any impact to traffic.” 

The plan is to utilize the temporary bridge during demolition and reconstruction of the existing eastbound and westbound I-80 bridges. At 400 feet long, this is the longest temporary bridge ever launched by UDOT. It consists of prefabricated sections that can be quickly assembled and moved into place with little impact to traffic. The structure is also cost-effective to build and can be used again on other projects due to the fact that it is made of highly durable materials, including 1.3 million pounds of steel.

Construction and launch of the temporary bridge was accomplished in six stages using the ABC approach, which is proven to reduce construction schedules, lessen impacts on the traveling public and minimize total project costs, among other benefits. After the foundational supports were built, the team used an ABC technique known as bridge-jacking to move the five bridge segments, ranging in size from 60 to 100 feet, into place. 

Starting at the west abutment, hydraulic jacks were initially used to lift the structure so that foundational rollers could be installed at 25-foot intervals between the bridge and the skid track. Next, the bridge segments were lowered onto the roller system and pushed into place by a Caterpillar D8 Dozer. A cantilevered launching nose served to guide the installation until it reached the east abutment, at which point crews used hydraulic jacks again to lift the bridge, remove the rollers and track, and lower the structure into its permanent position before adding metal decking and asphalt pavement.

The temporary bridge, located just east of the SR 201/I-80E junction in western Salt Lake County, was completed in January. After it opened, crews shifted eastbound I-80 traffic onto it and westbound traffic to the existing eastbound lanes. The traffic shift has allowed for two lanes to remain open in each direction while construction of the permanent westbound structure is underway.

At the time of reporting, workers were in the process of demolishing the original westbound structure. The project team expects to set the new girders, pour the deck, and switch traffic to the newly completed westbound I-80 bridge by summer 2020. Once traffic has been switched, reconstruction of the existing eastbound I-80 bridge will commence. Project officials anticipate that all Blackrock Reconstructed Project activities will conclude by the end of this year.