Bundled Approach Efficiently Mitigates Scour Damage for County-Owned Bridges

The County of Bradford, Pennsylvania recently packaged the repair of six bridges in a “bundled” approach to fix damages and mitigate future wear and tear caused by the scouring effect of heavy volumes of moving water, especially during heavy rain and flooding events.

The innovative program benefitted the county because it improved safety to the motoring public and as such, the bridges have been removed from PennDOT’s Scour Critical Bridge List. The bundling approach achieved economies of scale for the client because it allowed Larson Design Group as program manager to complete the design work efficiently as applied to six bridge and allowed the contractor to complete similar types of tasks on the six structures. Familiarity between LDG and the sole contractor provided for effective communication, smooth processes for invoicing, material certifications and general coordination on the projects which saved significant time. As a result, all six repairs were done on time and under budget.

County officials have said publicly that they were pleased with the outcome and would consider future program bundles in the future.

LDG’s design strategy was to install concrete underpinning and rock protection on the substructure of each bridge to remove scour and undermining and protect the structures from future scour issues. This has eliminated the need for the county to provide manpower and funds to monitor and document the bridges during future flood events as mandated for bridges on PennDOT’s Scour Critical Bridge list. It also allows the County staff to respond to other more serious issues during a flood event.  In the event there is damage to one of these structures from a flood event in the future, the County is likely to receive funding for the repairs because the bridge was adequately protected.

To achieve this outcome, LDG prepared and obtained permits for each structure from the Pennsylvania Department of Environmental Protection. LDG also prepared erosion and sedimentation plans, coordinated consent from adjacent property owners so that construction crews could have temporary access, and coordinated construction.  A shallow buried gas line was discovered at one of the sites that required crossing for access during design. LDG coordinated with the gas company and deployed timber mats to protect the location.  Construction at the site was completed with no issues.

Facts and Figures:

Clear Span Length Range = 20.5’ to 171’

Clear Roadway Width Range = 12.1’ to 25.9’

Minimum Underclear Range = 3.2’ to 10.5’

LDG Construction Cost Estimate = $199,600.00

As-Built Cost = $75,300.00

Bid Spread = $75,300 to $307,454.00

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