Tag Archives: instrumentation

I-94 and Sargent Road Interchange Reconstruction

David Wanlass, P.E. Project Manager

David Wanlass, P.E.
Project Manager

The I-94 and Sargent Road Interchange is a key transportation route for this area – especially when Michigan International Speedway is holding a race or the University of Michigan is hosting a football game. When MDOT began considering a major reconstruction of this area, the team understood careful planning would be required to keep traffic flowing.  What was not so apparent was how subsurface conditions would increase project complexity.

The realigned segment of Sargent Road and portions of the realigned ramps (with embankments up to 24 feet high) were to be constructed through significant wetland areas with up to 6 feet of peat, muck and organic silt at the surface, underlain by up to 39 feet of loose granular soils.  Construction could not proceed without treating these soils. Click on the video below learn how this challenge was solved.

P.S. This project approach is being presented at the 2014 Ohio Transportation Engineering Conference later today.

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Ann Arbor Wastewater Treatment Plant Upgrade

Ann Arbor, Michigan

Rehabilitation of the Ann Arbor Wastewater Treatment Plant was the largest capital project undertaken in the city’s recent history. The project included rebuilding half of the wastewater treatment plant and renovating the other half while remaining in continuous service. The City hired Walsh Construction Company to lead the work, and Walsh in turn tapped G2 Consulting Group to oversee the challenging underground work portion of the project.

Fast Facts

Project Owner

City of Ann Arbor

Scope

Because most of the work occurred underground, several geotechnical engineering firms were retained by subcontractors to perform work. G2 coordinated these technical efforts for consistency among the various disciplines on site and managed Walsh’s geotechnical risk.

G2 Services Provided

Geotechnical engineering
Geotechnical instrumentation monitoring
Retention wall design

Challenges/Solutions

      • One of the great challenges at this project site was the hydrogeological characteristics. The complicated artesian conditions coupled with the depths of required excavations and the presence of the Huron River along the perimeter of the project site required careful consideration and coordination among all the trades involved.  G2 provided an independent evaluation of site dewatering to help expedite the subcontractor submittal approval process and to evaluate the proposed phased dewatering across the site.
      • G2 constructed a mathematical model of the hydrogeological conditions and calibrated the model based on actual pumping and drawdown response on the project site. G2 used existing geotechnical data along with the geotechnical instrumentation data being collected during the course of the project to evaluate how much dewatering to perform during specific underground tasks across the site. This reduced the amount of energy consumed during construction by only pumping the amount required at specific locations.
      • Several small braced excavations were required during construction.  G2 designed earth support systems using the materials and equipment available on site allowing Walsh to self-perform work and expedite the schedule.

Smart. Results. Fast. G2 provided geotechnical solutions to address challenging conditions for this highly visible project, expediting the schedule, reducing costs and managing risk.

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Clintondale Pump Station

Clinton Township, Michigan


After nearly four decades of service, the Clintondale Pump Station was experiencing serious problems: its three, 500 horse power pumps had outlived their life, its operations were outdated, maintenance had to be done in confined space, and the lines leading to the facility were severely inadequate to feed the pumps. The Macomb County Public Works Office retained a construction team led by Walsh Construction to construct a facility to meet current and future needs.  Walsh turned to G2 Consulting Group to solve the challenging geotechnical conditions that were threatening construction.

Fast Facts

Project Owner

Macomb County Public Works Office

Scope

G2 Consulting Group provided geotechnical engineering consulting to the construction team to address artesian conditions on the project site.

G2 Services Provided

Geotechnical Design
Remote Geotechnical Instrumentation
Construction Engineering

Challenges/Solutions

  •  Extensive underground construction was required to construct the new pump station design, and the team knew that artesian groundwater conditions existed on site.
  • Instead of proceeding with the expensive jet grouting originally recommended to address this, G2 designed a depressurization plan to manage artesian groundwater conditions that included temporary earth retention systems and a geotechnical instrumentation monitoring plan to proceed with construction safely.
  • Key to this approach was a remote geotechnical instrumentation plan to continuously monitor groundwater pressures within the aquifer around the shafts and settlement within the cohesive soils at different depths to verify anticipated conditions. The use of continuous monitoring proved to be especially beneficial when structural questions arose during demolition and when the site lost power during dewatering.

Smart. Results. Fast. G2 developed a more conventional construction approach that ultimately saved the owner nearly $2 million, while enabling the construction team to better manage owner risk while maintaining the project schedule.

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I-94 & I-69 Interchange Reconstruction

Port Huron Township, St. Clair County, Michigan


The Michigan Department of Transportation reconstructed 3.7 miles of the I-94/I-69 interchange in Port Huron Township, St. Clair County, replacing bridges and reconstructing ramps. G2 Consulting Group and Toebe Construction teamed up to complete this $76 million project, maximizing construction efficiency and minimizing construction cost – while protecting nearby residences.

Fast Facts

Project Owner

Michigan Department of Transportation

Scope

3.7 miles of interstate, replacing bridges and reconstructing ramps

G2 Services Provided

Geotechnical engineering
Remote instrumentation monitoring settlement and vibration
Value engineering

Challenges/Solutions

      • The construction schedule was contingent on embankment soils settling. The team installed 12 vibrating wire piezometers to monitor pore water pressure changes as the embankments were constructed. In addition, a new innovative settlement cell system was used to monitor actual settlement of embankment soils to signal when bridge construction could proceed. This approach shortened the specified six-month waiting period by one month.
      •  Project budget was tight. Prior to starting, G2 recommended Elastizell as a more cost effective light weight fill in place of the polystyrene block that was proposed in the design, simplifying installation and reducing material costs. G2 also worked with Toebe Construction to optimize equipment efficiency and reduce construction costs, particularly during installation of piles, using static load tests and PDA testing to confirm design capacities for the piles.
      • Nearby residential structures were protected by specifying the maximum vibration levels allowed during construction. G2 then implemented remote vibration units to monitor vibration continually – without needing a field engineer on site – providing critical data while minimizing costs.

Smart. Results. Fast. G2 provided geotechnical solutions to protect  nearby residences and provide adequate support for the roadway and embankments, while shortening the project schedule and reducing costs.

Dugway Tunnel Project Underway in Cleveland

G2-49

Mark Stapleton, P.E.
Project Manager

The Northeast Ohio Regional Sewer District is completing a massive stormwater control project in the Cleveland area to protect Lake Erie, while meeting the needs of their growing community. G2 Consulting Group worked closely with Walsh Construction to submit plans and specifications for several shafts within 30 days of notice to proceed. Check out the video below for more project details.

(Double click on image below to see on full screen)

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