Associated Engineering developed a bearing replacement scheme to address the removal of PCB contaminants in the main truss span bearings of this highly visible eight-lane structure. Mandatory bearing replacement offered the ideal opportunity to upgrade the steel truss spans by installing base isolation bearings and enhancing seismic performance.
Seismic base-isolation design was carried out to extract optimal performance from the existing capacity-limited substructure. Key to bearing replacement was to develop a scheme to jack up the steel trusses, which had no jacking provision. Innovative designs were prepared for the complex temporary work needed to replace bearings of up to 7 MN load capacity.
Key services included:
- Inspection of the truss spans.
- Preliminary and detailed design for the bearing replacements.
- Integration of construction staging and public safety into the designs.
- Load rating of the truss spans using 3-D BIM and structural modeling.
- Structural evaluation, design, and construction services for concrete pier strengthening.
- Seismic assessment using modern bridge performance criteria.
- Development of environmental authorization applications, and liaison with Federal Agencies regarding application of PCB regulations to bridges.