Client: Jefferson County Commissioners
Year Completed: 2009
Project Cost: $560,000
The JC-29 bridge, locally known as Howe Road Bridge, is owned by Jefferson County. The old superstructure – a steel pony truss with timber stringers and deck – was removed in 2005 leaving just the cut stone masonry abutments and wingwalls. GD&F designed a replacement structure that complied with all PennDOT bridge standards.
GD&F designed a 62-foot single span, one lane, structural galvanized steel (W33 x 118 girders) bridge with a composite deck consisting of galvanized steel grid decking and half-filled with lightweight concrete. The existing stone abutments were capped to support the superstructure at a considerable savings in cost and construction time.
A sub-surface investigation showed that any bridge foundation work would create an acid mine drainage discharge. GD&F’s geophysical investigation revealed that suitable bearing conditions existed beneath the existing stone abutments, provided superstructure loads were minimized. GD&F examined several alternatives and selected the steel girder/composite deck bridge as the most cost-effective option. The proposed alignment was designed as a free-access, one lane facility that conforms to the PennDOT’s rural design criteria for rolling terrain.
The proposed vertical alignment (sag vertical curves and a crest vertical curve on both approaches) was changed to accommodate the increased superstructure depth and waterway opening. A one lane bridge was designed according to PennDOT’s “Right-Size” criteria.
GD&F did all preliminary engineering and final design work including the hydrology/hydraulics report, categorical exclusion report, type, size and location study, joint permit application, subsurface investigation, foundation report, plans, specifications, cost estimate, construction administration and inspection.
The project was completed on-time and within PennDOT’s budget parameters.