Interceptor Improvements Incorporate “Complete Streets”
Metropolitan Council Environmental Services (MCES) provides regional wastewater conveyance and treatment for numerous communities in the Minneapolis/St. Paul metro area, including Edina and Richfield. HR Green provided final design and construction support services for a new gravity sanitary sewer interceptor in Richfield. The new interceptor, which consists primarily of 36- and 42-in. diameter reinforced concrete pipe, crosses under a major interstate and courses through fully developed suburban streets.
Two portions of the project were accelerated to fit the construction schedules of the Minnesota Department of Transportation (MnDOT) and a school district. MnDOT required that the existing interceptor be re-located away from a bridge that crosses the interstate and was scheduled for reconstruction. HR Green prepared the sewer design and worked with MnDOT to incorporate the design into their contract documents for demolition and reconstruction of the bridge. The sewer construction was done concurrent with bridge demolition over a weekend closure. Schedule was critical since the freeway had to re-open on Monday morning. The sewer design was carefully prepared and reviewed to optimize its constructability within the tight weekend period. The freeway crossing was completed smoothly and the interstate was open for Monday morning rush hour.
The remainder of the project involved extensive, deep construction in urban streets with numerous utility conflicts. The alignment followed a four lane concrete arterial street in Richfield which had become outdated. HR Green’s transportation planners had been leading an effort to transform the major arterial streets in Richfield and saw the opportunity to work with MCES, the City, the Three Rivers Park District and the public to develop a Context Sensitive Solutions (CSS) that incorporates transit, pedestrian and bicyclist features in conjunction with installation of the new interceptor. The result is Richfield’s first “Complete Street” system. The process became a “win-win” scenario, with the City achieving an updated streetscape and MCES achieving a reduced street restoration expense. The project was constructed in three phases, beginning in 2008 and concluding in October 2011.
At a glance:
- HR Green provided final design and construction support services for a new gravity sanitary sewer interceptor that crossed under a major interstate and coursed through fully developed suburban streets.
- This project required extensive coordination with MnDOT and a tight construction schedule that needed to be completed in one weekend.
- HR Green’s water and transportation groups worked together with MCES, the City and other stakeholders to install the interceptor and restore an outdated street to incorporate Context Sensitive Solutions (CSS). This achieved an updated streetscape for the City and MCES achieving a reduced street restoration expense.
- The project also exemplifies the application of design flexibility by engineers in service of the public interest.