The I-15 Exit 118 Interchange project in Mesquite, Nevada provided an exciting and innovative bridge system for its owners. Funded by the Regional Transportation Commission of Southern Nevada, the new crossing allows industrial truck traffic access to the freeway without impacting nearby casino resort guests. Although it was originally designed as a two-span girder bridge, the Nevada Department of Transportation (NDOT) and the City of Mesquite allowed for alternative conceptual designs to be submitted for approval. Atkins North America, the project's engineer, and Meadow Valley Contractors (MVC), the project's contractor, worked closely with Contech Engineered Solutions to brainstorm the best option. MVC had some familiarity with Contech's products and wanted to learn more about them. After the precast arch options were presented, their approach to the project began to take shape.
Many factors played a role in deciding which bridge system would work best, eventually culminating into twin 78’ x 27'-10" E-Series BEBO® Concrete Arches, 76’ in length. With both NDOT and the City enthusiastic about this precast BEBO option, the proposal was accepted, and the design phase commenced. The precast, modular system, complete with MSE headwalls and wingwalls, was installed over each side of I-15 with the local road, Lower Flat Top Drive, running across the top.
Overall, the precast option added more value to the project than the original steel girder option. The speed of construction, for instance, allowed the contractor to meet the aggressive demands of the schedule, while also reducing negative impact to motorists. In addition, cost savings were realized in terms of material, equipment, and labor. With the units being produced off-site, fewer labor hours were required on-site, resulting in a safer environment for vehicles and workers. Last but not least, NDOT and the City were excited to be the first to install such a unique and aesthetic looking bridge to the Nevada interstate.
A major component of the project was managing the schedule. Shutting down lanes of traffic on a busy interstate fosters a lot of negative attention. To minimize disruption to traffic, installation of the BEBO structures started at night and continued through the early morning hours. During that time, vehicles were routed to a bypass road that would eventually become the ramps leading to and from the interchange. In all, 76 precast arch pieces were lifted into place via two cranes. There were minor challenges along the way, but working as a team, Contech and MVC found solutions and kept the project moving forward. In fact, even though five nights were allocated for the bridge installation, only three were needed.
A key factor of the project involved enhancing the bridge's design, thus raising the aesthetic value. Contech’s marketing department produced a conceptual image of the bridge depicting the desired visual elements. Because MSE walls are commonly used in conjunction with BEBO arches, the image also included art on the end walls featuring the natural views of the nearby Virgin Mountain Range. At the end of construction, the conceptual image very closely matched the completed bridge.
Perhaps the most unique element of the project was the utilization of a BEBO Arch system as a freeway interchange. Not only did the bridge provide vertical clearance for 60 feet of right-of-way, it was the first BEBO ever utilized in an interchange configuration. When compared to a traditional bridge, and in addition to the benefits mentioned above, the nature of the buried arch system offers minimal maintenance for the life of the bridge.
"The BEBO arch provided by Contech was the right choice for this project," concluded Jed Wheeler, Project Manager with MVC. "Contech's design team was responsive in submitting the information needed for NDOT's approval. Their construction team was on-site while installing the arch segments to help with any questions or concerns. In the end, all key stakeholders were happy with the functionality and aesthetics of the bridge structure, and we look forward to working with Contech on future projects."