Some time ago in 2015, the City received a call from a resident regarding sinkholes in the grassy areas near the structures that span the waterways in the Palm Beach Isles community. In the process of trying to determine the cause of the sinkholes, City staff noticed the condition of the structures and felt there was a need to have a structural analysis performed to determine the structural integrity of the waterway spans. Staff contacted Erdman Anthony, one of the City’s engineering consultants under contract, to perform the structural analysis. Erdman Anthony then retained the services of Alan Gerwig and Associates (AGA) to perform the structural analysis. In November of 2015 AGA completed their analysis of the over the water structures and provided the City with a written assessment as well as probable cost estimates to correct the issues.
According to the AGA report, the structures are beyond repair and need to be replaced due to the level of deterioration that has taken place. In order to proceed with replacement of the structures a design of the structures has to be completed. The design fee proposed by Erdman Anthony which includes permitting, geotechnical engineering, maintenance of traffic concepts, habitat survey, environmental service and bridge design is $292,906. Preliminary estimates to replace the structures are approximately $1.9M which includes permitting fees and contingency; however, more accurate costs will be provided once the design of the structures is completed.
Based on the report’s recommendation and the visible condition of the structures, staff requests that City Council approve the work order with Erdman Anthony to provide design services for the over the water structures in the Palm Beach Isles community.
During the past four year, staff has moved expeditionsly to design and permit the strucutres replacement. During the process, it was discovered that there are protected species in the waters adjacent to the bridges, specifically Johnson Seagrasses. The discovery of this endangered species has significantly altered the permitting process and the permits required by the Federal Government are now lengthy.
During the period of 2019 and 2020, AGA has been performing monthly inspections to monitor the condition of the structures. On Friday April 17, 2020 the City was notified by AGA of accelerated deterioration on the southern structures and the deck of the further west strucutres. City Executive staff met with AGA office on Monday April 20, 2020 to visually inpsect the structures and provide direction on solutions. Staff met with AGA and David Logan of Murray Logan on Monday as well and provided the plans and scope for the temporary stabilization.
Due to the natuare of this safety issue, the City shall immediately move to stabilize the structures as recommended by AGA.