Heavy Underground Distribution Manholes & Vaults

St. Louis, Missouri
Ameren Missouri
Start Date
August 2012
Completion Date
Construction Cost
Total $23M

In order to improve customer service and reliability throughout their service territory, Ameren is investing millions of dollars to make improvements to their heavy underground electric distribution system in St Louis and the surrounding region. This system includes over 10,000 heavy underground distribution vaults and manholes of various ages and condition.

Ameren selected DMA to provide professional services for this Project through multiple Indefinite Delivery/Indefinite Quantity (ID/IQ) contracts. The Project required a multi-discipline team of Engineers and Surveyors.

Our Structural Engineers and Inspectors performed inspections of the electric vaults and manholes. These specially trained field personnel performed confined space entry into energized structures in order to maintain electric service to customers. Detailed condition evaluation reports were prepared to document existing conditions including physical geometry; obstructions and clearances; and structural deficiencies.

Each manhole and vault exhibited different characteristics and challenges. In most cases, 3rd party utilities ran through or adjacent to the structure thereby making repairs or modifications difficult. However, similar structural deficiencies and repair techniques were identified early in the Project. DMA developed Standard Drawings and Specifications for common repairs which were adopted by Ameren for future projects.

DMA also provided topographic, utility, and property surveys and developed plans for utility adjustments, relocations, and site restoration.   Our Engineers coordinated with Ameren and other utility companies to schedule outages for required utility relocations. Many of the structures were located within high-traffic streets and roadways. Consequently, traffic control and construction phasing plans were developed by our Civil Engineers to insure the constructability of the improvements while minimizing the impact on the traveling public. We coordinated these issues with local transportation authorities and regulatory agencies for approvals and permits.