Best Highway/Bridge: NDOT 3935 Fernley Bridges

NDOT 3935 Fernley Bridges

Fernley, Nev.

BEST PROJECT

Submitted by Q&D Construction

Owner/Civil Engineer Nevada Dept. of Transportation (NDOT)

Lead Design Firm NDOT; Jacobs

General Contractor Q&D Construction

Structural Engineer Jacobs

Eight bridges along Interstate 80 stand ready for any movement, thanks to an $18-million seismic retrofit program. It involved upgrades to four westbound and four eastbound bridges: I-700, I-717, H-844 and I-740.

Unlike most projects that only use one seismic retrofit approach, this project utilized a multimethod approach, which included steel shells for column reinforcement, cast-in-place concrete for substructure strengthening, composite fiberglass wraps and fiber wrap applications. For example, crews installed steel casings around the bridge columns, which had to be fabricated and welded on site. To install carbon fiber reinforced protection wraps on the underside of several bridge superstructures, workers had to perform these tasks upside down—this project was only the contractor’s second time using this technique.

The combination of solutions ensures that the reinforcement efforts will support specific structural needs and ensure I-80 remains a vital economic corridor during any seismic event.

Photo courtesy Q&D Construction

Full traffic crossovers were built to temporarily shift traffic to one side of the freeway during construction. Some of the bridges required pier cap extensions and post-tensioning as part of seismic restraining upgrades as well.

During excavation for the retrofit pier footings at the I-717 bridge, an effort that included installing shoring beneath the existing structure, crews encountered an unforeseen utility line directly in the work area. The team responded by resequencing work. Drilling and doweling began on the above-ground faces of the existing pier walls, while the earthwork crew simultaneously advanced construction of the traffic crossover. This allowed for open excavation to fully identify the utility in a safe manner while maintaining progress on the critical path.

Also on the I-717 structure, crews placed ultra-high-performance concrete (UHPC), marking the first time the material has been used in a Nevada transportation project. UHPC is more than seven times stronger than conventional concrete and has the unique property of forming a non-Newtonian fluid when mixed, which allows it to flow under pressure but set rapidly once placed.