LH Ford Bridge Project
The LH Ford Bridge, constructed in 1968-69, includes 28 diverse spans. Our recent efforts focused on spans 22 to 24, featuring a segmental box girder deck supported by scaffolding. These particular spans include 28.0m back spans and a central span with 19.32m long cantilever arms that uphold a 24.12m drop-in box girder span. The structural support includes an expansion bearing at one end and a hinged bearing at the other at the half joints supporting the drop-in girder. Additionally, piers 21 through 24 utilise mild steel hinged bearings. Currently, the bridge experiences significant sag deflections and a lack of strength at the half joints. To address these issues, our proposed enhancement plan includes the addition of two new piers, strategically placed at each half joint to reinforce structural integrity.
As the Project Director and Structures Lead for this project, Vince was responsible for the delivery of the load rating assessment review of the superstructure and led the load rating assessment of the substructure. Vince Scolaro, Mehran Ameli and Brendan Quinn were also responsible for the checking of the final design rectification works for the superstructure, detailed design of the new piers, the design checking of the existing superstructure for all temporary works required and the drawing delivery for the bridge substructure and all temporary works. This included assessment of the existing bridge superstructure for the proposed hanging scaffold, identification of all bridge superstructure reinforcement to ensure minimal existing reinforcement was damaged for the installation of all bearing plates and external tensioning anchors, assessment of the existing piers for the temporary bracing required to ensure alignment of the new piers with the bridge bearings under thermal variations and responsible for all CPS activities. The proposed strengthening design involved the addition of external pre-stress to both the main span and back spans, addition of 2 new piers (one under each half joint, replacement of the bearings to include a soft (elastomeric bearing) and hard (pot bearing) at each new pier, provision of new shear keys at each new pier and remediation of the existing concrete barriers.
Technical innovations achieved
Development of a temporary bracing / stressing system for the jacking of the existing bridge and construction of the new bridge bearings and shear keys under live traffic.
Benefits to the Client
Traffic restrictions virtually eliminated (with the exception of the bridge jacking process).
