Pump Station A Rehabilitation

location

New Orleans, LA

owner

New Orleans Sewerage & Water Board

approx. contract value

$3,517,000

This project's objective was to restore the structural integrity of this pumping station located in a historical preservation area.

scope of work

The building’s foundation was sinking, which caused severe structural failure to the walls. The state of the building at the time of award included a significant risk of structural failure as evidenced by numerous structural cracks in the existing fa├žade.

The work was designed to install micropiles adjacent to the existing foundation, concrete encasement to enlarge the existing grade beam, construction of a 34′ tall concrete backup wall, beams and pilasters, brick crack repair, concrete sidewalk and re-installation of the floor slab.

Upon mobilization, Cycle determined through survey monitoring that the building was in active failure. The building was temporarily braced as required. As a result of the foundation continuing to settle, Cycle provided a value engineering option to install helical piles, which could be installed a lot quicker than micropiles and would arrest the settlement of the building a lot faster. Additionally, due to the deteriorating existing masonry wall conditions, Cycle suggested installing the backup wall via shotcrete in lieu of the traditional cast in place. Cycle felt that pouring concrete conventionally against the existing wall would present problems based on the liquid head of the concrete. Installing a shotcrete wall would eliminate the majority of the forming and allow the material to be placed in a systematic fashion that would limit the pressure on the existing wall. This allowed a more efficient installation of the concrete backup wall and expedited the time needed to achieve structural stability.

Once the new concrete foundation was installed and the roofing system shored to take pressure off the walls, the masonry walls were repaired with a combination of helical stitching and epoxy/grout injection. Rebar was installed against the existing wall and supported from the new foundation. Simpson Heli-Tie Helical wall ties were installed, and then the shotcrete was installed in lifts beginning from the foundation to the top. The wall was then hand-finished and floated prior to painting.

The project was a collaborative effort with the design team, ownership and our team coming together to tackle some unique existing conditions. The use of shotcrete in this application is not common in our market. At Cycle, we try to always look for smarter and more creative ways to provide the desired end product and limit risk for all involved.

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