Project Type: Evaluation, Design
The Vital Structure: 

Steam Tunnel Sump Pit Repairs

Issue

  Vital Structures was contacted to evaluate leaking and deterioration of a concrete sump pit in a steam utility tunnel. The Owner planned a phased project to update five (5) sump pits in their tunnel system, and retained Vital Structures for structural engineering and remedial waterproofing services
Concrete Sump Pit
Groundwater infiltration into the sump pit was controlled using hydro-active chemical grouts and crystalline cementitious grout.

Diagnosis

:After performing abatement and draining the sumps, we performed concrete sounding and perform exploratory test cuts of the sump pit which is located approximately 30’-0” below grade. Our evaluation found that the sump pit walls had previously been repaired to control a full-depth hole in the sump wall. The repair had failed, and the sump had been allowing ground water to flow into the sump system for years, contributing to the accelerated decline of the pumps.      

Solution

Vital Structures prepared design documents and performed construction administration for the structural and waterproofing repairs, including five (5) sump pits and one (1) elevated platform. The project scope included the following:

  • Partial- and full-depth concrete repairs, including a continuous ‘scab’ wall overlay vertical repairs.
  • Polyurethane and acrylate grout injection waterproofing to control groundwater infiltration into the sumps.
  • Crystalline cementitious slurry waterproofing ‘liners’ inside of the sump pits.
  • New bar grating covers with embedded steel shelf angles and pre-located penetrations, as coordinated with the mechanical engineer.
  • A new overhead access platform at the intersection of two (2) existing concrete tunnels.
Galvanized steel bar grating covers.

Evaluate. Guide. Revitalize.

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