Independent Cost Estimating and Construction Engineering Inspection on a Critical Downtown Connector

Nashville is one of the fastest growing cities in the United States, according to data from the U.S. Census Bureau, attracting people from around the world with an interest in the Music City.

The Broadway corridor is a critical route into downtown Nashville, with the State Route 1 (US 70) Broadway Viaduct — known locally as Broadway Bridge — carrying tens of thousands of vehicles every day for employment, entertainment and tourism. The safety of local vehicle traffic and pedestrians led the Tennessee Department of Transportation to replace the 73-year-old bridge, which had outlived its lifespan, was starting to deteriorate and became too costly to maintain.

HDR was selected by TDOT as the independent cost estimator, part of a construction manager/general contractor delivery method. Our team collaborated with TDOT and the contractor to initially estimate 100% cost of replacing the Broadway Viaduct Bridge before construction, as well as 60% and 90% design milestones. We also reviewed the contractors schedule to check for feasibility.

Once construction of the bridge was approved by TDOT, our role transitioned to a construction engineering inspection consultant. Our team provided project coordination among various stakeholders, led the inspection process and maintained records.

Coordinating the Build to Limit Impact

In addition to connecting downtown Nashville with other parts of the city, the Broadway Viaduct Bridge stretches over five active railroad tracks and 11th Avenue, a main north and south connector that provides access to the Gulch, a rapidly growing commercial and residential development area southwest of downtown Nashville.

Construction of the bridge was scheduled on an accelerated 10-month timeline. Efficiency was paramount throughout construction to maintain accessibility and limit the impact on thousands of daily commuters, train traffic and area businesses. The bridge remained open to traffic while the replacement bridge substructure was built within 1 foot of the underside of the original bridge structure. The work was done using Accelerated Bridge Construction techniques for precast bridge elements for the superstructure and hybrid cast-in-place and precast elements for the substructures.

Once the substructure was complete, contractors took just nine weeks to demolish and remove the old bridge and install the rest of the new structure before reopening to traffic. During that closure, the contractor worked nearly 24 hours a day, leading us to add additional inspection resources to cover the demanding construction schedule. To accommodate a request from a nearby hotel to reduce daytime noise, we coordinated nightly construction to saw concrete from the old bridge into panels, remove piece by piece and crush at another location.

Contractors also shortened the length of the new bridge to avoid disruption to train traffic on five active railroad lines underneath the bridge. Interior bents supporting the old bridge were removed and replaced by two bents on either side of the structure. The layout change included a single long span of girders that avoided construction in the railroad right of way and increased the vertical clearance to allow for safe passage of taller trains.

The project finished on time and under budget. The Broadway Viaduct Bridge was officially opened in October 2023 during a ceremony with the Tennessee governor and the Tennessee Department of Transportation.