YARDLEY, PA – The Delaware River Joint Toll Bridge Commission recently awarded a contract for professional engineering services to inspect the in-water masonry substructures that support the agency’s multi-span roadway and pedestrian bridges.
A primary focus of the effort will involve examining whether river currents have eroded rock, gravel, or sand around piers and select abutments, potentially compromising a respective bridge’s structural integrity. The erosion condition is called bridge scour, and it is the most common cause of bridge failures in the United States and around the world.
The Federal Highway Administration’s (FHWA) National Bridge Inspection Standards require the performance of underwater inspections at an interval not to exceed five years. The last inspections of Commission’s 20 river crossings occurred under a 2021 contract.
Between 2010 and 2011, the Commission conducted an extensive series of substructure repairs and scour-remediation measures at its network of piers and abutments, some of which have portions dating back to the early 19th century or are founded on submerged rock-filled timber cribs. That ambitious project was based on the findings of underwater inspections conducted after a series of floods that inundated the region between 2004 and 2006.
The latest underwater inspections contract was awarded at the Commission’s April 27 meeting to Pickering, Corts, and Summerson, Inc. of Newtown, PA for a not-to-exceed amount of $399,194.68. The engineering firm is expected to begin work in the coming weeks and provide assessments of each bridge’s substructures including – but not limited to – the following factors:
- The physical condition of substructure elements
- The physical condition of substructure protective devices
- A bathometric survey at piers
- Cross sections up and downstream
- The condition and location of streambed materials
- The condition and stability of waterway channels
- The condition and stability of channel protective materials
- An observed scour assessment
The consultant is responsible for all project management, administration and coordination with the necessary agencies for safe completion.
The inspection process will be conducted at 19 of the Commission’s 20 river crossings. The Easton-Phillipsburg (Route 22) Toll Bridge will not be part of the study process because it is supported solely by two land piers, making river piers unnecessary. (Note: Land-based substructures that keep dry during normal river levels get inspected every two years by the Commission’s general engineering consultant.)
In the event that an inspection uncovers a potentially major finding at a respective bridge, the consultant must immediately inform the Commission for purposes of determining whether immediate corrective or remedial measures are warranted. Upon completion, the consultant will deliver a comprehensive report with a summary of findings, photographs, sketches showing scour and undermining conditions where they exist, conclusions, recommendations and cost estimates for repairs at any river crossing corrective actions.
