Avondale (State Street) Bridge
The State Street Bridge in Avondale will be replaced with a 36’-6” single-span adjacent pre-stressed concrete NEXT beam superstructure with a composite reinforced concrete deck. The superstructure will be supported by new, reinforced concrete abutments with stone pattern architectural treatments on the upstream and downstream faces. Rock will line the stream banks in front of the abutments to protect them from the effects of scour. The geometry of the new superstructure will differ from that of the existing bridge, eliminating the east (downstream) sidewalk and providing a wider curb-to-curb width of 26’-0”, while a new 5’-8” wide concrete sidewalk will replace the existing west (upstream) sidewalk. Guide rail will be installed on all approaches to the structure and will transition to Type 10M Bridge Barrier. Stone pattern architectural treatments also will be included on the outside of the bridge barrier walls. Two underground utilities within the project limits, a gas main and a water main, are being relocated as a part of this project.
The existing bridge closed to traffic on July 13th. Within a week of the bridge closure, environmental controls consisting of silt fence and compost filter sock were installed under the guidance of an environmental subcontractor. In addition, cofferdams were installed along both streambanks to allow for removal of the existing abutments and excavation for the new abutments.
The existing PECO gas main was temporarily capped on each side of the bridge as planned for the duration of the reconstruction, and demolition of the bridge began. Waterline relocation has been postponed due to unanticipated excessive cost. The County is working to obtain both estimated force account costs from the contractor and additional estimates from specialized utility contractors.
Beam CollapseOn August 10th, during removal of the bridge superstructure, a beam collapsed resulting in partial overturning an excavator. Both the beam and the excavator came to rest on the cofferdams, completely spanning the stream and not entering the water. No one was injured in the incident. The contractor immediately installed environmental controls across Indian Creek in case of a fluid leak and carefully emptied fuel from the excavator to prevent potential spills during removal of the machine. The PA Department of Environmental Protection was notified and determined that a site visit was not needed as the environmental threat had been mitigated. The excavator was up-righted onto the roadway by late evening with the assistance of a commercial towing company, and bridge removal continued the following day.
As of August 24th, the bridge superstructure, including the sidewalks, bridge rail, deck, and beams have been removed. The abutments are removed almost to stream level. Abutment demolition will continue after relocation of the water line.
Subsequent to capping the existing main, PECO determined that a temporary main is needed to maintain the current level of service to residents, and as such, will install a temporary gas main downstream of the bridge within the next few weeks.
Construction of the new bridge is expected to continue through winter. The opening of the new bridge is anticipated for mid-spring when warmer temperatures allow for completion of the new approach roadways in accordance with PennDOT standards.
Funding is provided by the County of Chester, with the County seeking 80% reimbursement in state funds through retro-reimbursement. The project must meet PennDOT standards as it will ultimately be funded by the state.