MonFayette Expressway over the Monongahela River
The MonFayette Expressway is a new 26 mile long urban toll road being built by the Pennsylvania Turnpike Commission that will connect the former industrial areas of the Monongahela Valley with Pittsburgh. The MonFayette crosses the Monongahela itself between Duquesne and North Braddock, Pennsylvania. The crossing requires dual 4 lane bridges. 1100 foot long spans are required in order to provide clearance for the heavy barge traffic on the river. Mr. Gottemoeller provided aesthetic advice to the engineering team during bridge type selection and preliminary design.
The bridges' surroundings include the Edgar Thompson Works of U.S. Steel, a Monongahela River lock and dam, railroad yards and bridges and vacant brownfield sites, all separated by wooded hillsides from the rest of the area. The thrill rides of the Kennywood Amusement Park overlook the site from the south. There are no residential communities nearby and the more distant ones have expressed no interest in the bridge. The visual challenge was to find a bridge that fit the overall form of the valley and the large elements within it.
The type study considered truss, arch and cable stayed bridges. Performance elements such as constructability and maintainability were investigated along with cost an appearance. The cable stayed bridges ranked best on all three factors, performance, cost and appearance. The tower designs have been further refined to optimize their appearance.
Geotechnical studies are now underway in preparation for final design. No completion date has been established.