Client: Grand Traverse County Board of Public Works
Location: Grand Traverse County, MI
Prime Consultant NTH Consultants, Ltd.
Total Project Budget: $6.6 million
NTH Project Budget: Ongoing Project
Start Date: July 2005
Completion Date: August 2005
Grand Traverse County Septage Treatment Facility
The Grand Traverse County Septage Treatment facility was constructed in 2004-2005. Designed to provide septage treatment for waste haulers throughout the county, the facility will provide pre-treatment of the fluid component of the septage. The treated fluid will be passed on to the Traverse City Sewage Treatment Plant for further processing and disposal. The solids will be processed into a Class A bio-solid, suitable for landfill disposal or further processing into soil enhancer material.
As construction of the plant was nearing completion, the East wall of the East Membrane Tank, which was full of septage, collapsed. The falling wall and released septage hit the adjacent dewatering building to the east, causing damage to the west wall of the building and to the electrical room attached to this building. The majority of the septage was retained within the boundary of the site, and was cleaned up in a short time after the spill. Given the critical nature of the electrical room equipment, the entire facility was shut down, with the exception of the Unload building.
Project Scope The failure of the East membrane tank raised concerns about the integrity of other tanks and structures at the site. Grand Traverse County retained NTH to conduct a failure assessment of the East Membrane Tank and to perform condition surveys of the other tanks and buildings at the site, including:
Direct observation of the failure areas
Review and evaluation of the project plans and specifications
Concrete core sampling
Petrographic analysis and compression testing of the concrete
Nondestructive and destructive testing to locate and evaluate the reinforcing steel
Soil testing to determine drainage characteristics
Following this assessment and identification of the reason for failure, NTH was retained to work with the designer to share information and assist in development of repair plans and specifications. Once repair/reconstruction plans are finalized, remedial measures will be implemented by the original design/build joint-venture. NTH is being retained by the county to provide full-time and part-time construction monitoring through the repair/replacement stage.
Project Application NTH quickly responded to the client’s request, mobilizing a team to observe conditions and collect core samples of the concrete. A program of nondestructive and destructive testing of the concrete and reinforcing steel was initiated shortly thereafter. Through observation, testing and review of the original design, NTH determined the failure mechanism and other design and construction issues requiring attention.
In the press and public eye from the beginning, this high-profile project afforded NTH the opportunity to demonstrate its commitment to maintaining a professional demeanor in working through a challenging situation. Taking special care to maintain a good working relationship with the designer and contractor, NTH created an atmosphere that enhanced the engineering of this re-design process, meeting critical project schedules and deadlines to deliver a quality resolution to the project issues.