Redmill Pedestrian Bridge

The Redmill Pedestrian Bridge was designed by Gibson-Thomas for Indiana County. The bridge lies several miles north of Vintondale in Blacklick Township, Cambria County and crosses the North Branch of Blacklick Creek. It is located along a portion of the former Cambria & Indiana Railroad Rexis Branch. Floods in 1972 and 1977 had damaged the rail line and had washed away the bridge at this location. By 1993 the railroad was ceasing operations and had donated the right-of-way for trail use.  Reconstructing the bridge would allow the connection of two separate portions of Rails to Trail enhancement projects, all funding under Section 130 of the 1991 Intermodal Surface Transportation Efficiency Act legislation.

The existing abutments were initially evaluated for stability in 1996. The north abutment had been subjected to severe scouring events during previous floods and was found to be five feet into the stream channel. Large portions were also missing. Therefore, to alleviate future scour concerns, the proposed design moved the abutment 20 feet to the north and the bearing elevation of the footing was placed on competent rock 30 feet below the trail surface. The structure to be placed on these abutments was a prefabricated steel thru-truss bridge with a span of 120’-0” and a composite glue-laminated deck. Additionally, specialty guide rail composed of pressure-treated lumber was designed an incorporated to maintain the aesthetic appeal of the trail approaches.

Significant consideration was given during the design phases to the constructability of the finished product. The project is located in a very rural area along the border of Cambria and Indiana Counties and was only accessible via narrow, winding township roads and the trail itself. The bridge structure was designed with strategically-placed field splices to ensure that the girders could be delivered to the site. Also, access to the southern portion of the site was hindered by the inability to use the southern two miles of existing trail as an access road. Therefore, a temporary causeway across the stream was utilized to access the southern abutment and trail approach.

The Redmill Pedestrian Bridge and the adjacent trail segments opened for use in 1999. This bridge provided for a connection between the main Ghost Town Trail at Vintondale to the south to the SR 0422 corridor (and future expansions) to the north.

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Gibson-Thomas is a multi-discipline consulting engineering firm established in 1916 in Latrobe, Pennsylvania. Our past experience, key staff and commitment to total client satisfaction are the major factors that our clients consider when contracting with Gibson-Thomas.

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