Excavation/Site Development: 96th Street & Frederick Street Emergency Culvert Construction

Omaha culvert construction

Roloff subcontracting reinforcing steel installation, allowing crews to form and pour concrete more efficiently.

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Our nation’s infrastructure is in critical need of repair and the 96th Street & Frederick Street Emergency Culvert Construction project in Omaha, Nebraska, was just another example.

96th Street, one of Omaha’s major collector roadways, began to show signs of settlement in spring 2021. Further investigation into the settlement led to the decision to close the street and replace a culvert under the street.

“The hazard was created by a deteriorated corrugated steel plate culvert. Corrosion at the invert of the culvert led to material loss and a loss of structural resistance to lateral earth forces. We witnessed a significant and sudden settlement event on March 25, 2021 that raised concern to the level of an imminent collapse, and we made the decision to close the roadway,” said Austin E. Rowser, PE, Construction Engineer, City of Omaha, Public Works Department.

The 96th Street and Frederick Street Emergency Culvert Construction project consisted of removing an existing 18-ft by 12-ft CMP elliptical pipe culvert, and the construction of a twin 10-ft x 12-ft box culvert and associated storm inlet piping, as well as street reconstruction. The primary goal of the project was to design a new culvert that exceeds the existing culvert’s hydraulic performance, while limiting the impacts to the channel and surrounding area. The project was delivered using design-build contract delivery, which allowed construction to begin well head of final design. The contract was award to Omaha-based contractor L.G. Roloff Construction Co. Inc., with Nexus Alliance as the engineer.

Omaha culvert construction

The approximately $2 million design-build project fixed the issue of settlement, increases safety for motorists and pedestrians, and allows for future capacity improvements in the future.

Channel flows were a major factor on this project for a couple reasons. First, there was no historical information to determine anticipated flows in the channel for either dry or wet weather events. Second, the project location was in an established neighborhood, so the construction footprint had to be kept to a minimum. Roloff determined the flows from wet weather events could not be pumped and crews would have to do their best to work around wet weather events.

Roloff deployed a bypass system that would handle the usual dry weather flows, and closely monitored the forecast to avoid any major setbacks due to channel flows after wet weather events.

As with many projects on existing roadways, utility coordination is critical to a project’s success. Given the emergency status of this project, there was no utility coordination up front. Due to the design-build delivery method of the project, Roloff was able to work with the utilities during design to figure out the most cost-effective solution for all parties involved. This resulted in some temporary removals and some temporary relocations.

Teamwork

Roloff self-performed 90% of the project scope. For the first time in company’s history, Roloff utilized Reinforcing Steel Installers (RSI) as a subcontractor to install the reinforcing steel. The use of this subcontractor allowed Roloff to form and pour sections of the structure much more quickly vs. relying on its our own people. RSI turned out to be a valuable partner. They were there when they said they would be there and were very efficient. This approach will now be considered on future projects.

Ready Mixed Concrete Co. supplied the concrete for the cast-in-place box culvert. The concrete design mix was perfect for the job and there were no quality issues. Ready Mixed Concrete Co. has a long history of providing quality material and this job was no exception. Drake-Williams Steel supplied the reinforcing steel for the culvert. Their team worked closely with Roloff to deliver steel as areas reached final design and as schedule demanded. ASP Enterprises consulted on the stream bank stabilization and furnished the gabion baskets to complete the work.

Omaha culvert construction

The roadway was restored and back to normal just before the holiday season.

Project Benefits

The first and most important benefit of the project is safety. Had the settlement problem not been discovered and fixed immediately, it could have led to accidents or injuries for motorists or pedestrians and a public relations problem for the City of Omaha. Roloff Construction’s rapid response and flexibility related to project design and the City’s decision to completely close the roadway to provide adequate space for construction created efficiencies that resulted in higher production and an earlier project finish.

The roadway was restored, and things were back to normal just before the holidays. Due to increasing congestion in the area, there are plans to widen 96th Street in the future. The upside of the emergency nature of our project is that a future street-widening project can now be completed without box culvert construction, which should shorten the duration of that project.

“The timeline for completing this approximately $2 million project was very quick, especially given the size of the culvert and the needed utility relocations,” Rowser said. “The city is very happy with the outcome of this project, the timeliness of Roloff, the quality of construction, and the urgency with which Roloff conducted the work.”

Quick Facts

Project Name: 96th Street & Frederick Street Emergency Culvert Construction

Construction Category: Excavation/Site Development

Project Owner: City of Omaha

Contractor: L.G. Roloff Construction

Engineer: Nexus Alliance

City / State Project: Omaha, Nebraska

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