The Culver Line Viaduct, located in Brooklyn, between the tunnel opening of Carroll Street Station and the tunnel opening south of the Fourth Avenue Station, was built in the 1930s. The goal of this project was to rehabilitate the concrete viaduct deck including removing existing track, performing direct current (DC) power and signal work, and installing cables within the viaduct limit to permit repair and rehabilitation of the existing concrete deck.
Judlau Contracting was the general contractor for the project. The work entailed removing and replacing existing waterproofing, protection concrete, and the deteriorated protective netting from the underside of the concrete deck. Upon starting the work, it quickly became apparent that the deterioration of the concrete structure was far greater than anticipated, which posed a scheduling risk because new waterproofing could not be installed until the structure was rebuilt. Some areas of the viaduct were so badly deteriorated that they presented an immediate safety concern for the riding public and surrounding buildings. Judlau worked together with the owner to expedite the critical repairs, without major disruption to train service.
The work also included the replacement of ballasted track with low vibration track (LVT) using LVT resilient concrete blocks. There was also a significant amount of signal work, including the replacement of signal switches, DC work, providing new turn outs between tracks B3 and B4, converting track switches from 25 N/S to diamond cross over (new interlocking), and installing new communication based train control (CBTC) ready signal switches within the viaduct limit. A new signal relay room was constructed to support the addition of the interlocking and CBTC signal. A new central instrument room was also built.
Structural repairs to the deck first required removal of existing tracks, traction power system, signal system, and waterproofing. Most challenging was the requirement that these removals had to be accomplished while train service remained in operation on adjacent tracks. In addition, the structure had protective netting underneath and a mesh pinned to the parapet and walls to protect the public from falling debris. What made this a particularly challenging task was that most of the netting was over occupied buildings and active city streets, and as high as 100 feet above street level. The mesh on the outside of the parapet that was also used to protect the public needed to be removed to an elevation of 5 feet from the top. This was necessary to make the concrete repairs and apply a protective structural fiberglass coating. This was done on the outside of the structure that wrapped over the top of the wall to secure the parapet and prevent any more spalls or debris from falling and prolong the useful life of the viaduct.
Quality and safety
Judlau incorporates quality and safety in all aspects of its work. The quality work plans were developed by the quality engineer in conjunction with the project team and field supervisory people. Based on the contract requirements and manufacturers’ recommendations, Judlau developed a plan to address how specific components of the work were to be constructed. The final product from these meetings resulted in clearly written explanations and procedures so that everyone understood the requirements when carrying out the work.
It is Judlau’s utmost goal on every project to avoid accident or injury. Over the life of the Culver Line project, the company was able to maintain a lost time rate and a recordable rate that was less than the national average. Considering the project’s location and materials and the logistics involved, this was a remarkable accomplishment. To promote jobsite safety, Judlau held monthly safety breakfast meetings with the entire workforce, including subcontractors. During the meetings, the team leaders reinforced the safety message to the workforce, addressed any incidents to avoid recurrences, and shared relevant information. When there was no incident, Judlau distributed safety awards to the top five individuals who demonstrated a strong commitment to safety. This had a positive ripple effect across the entire project team.
Benefits for society
The project made critical repairs and updates to the track and signal system, ensuring a safer and more reliable ride for the general public. It rehabilitated the right-of-way for enhanced public safety to the surrounding community. The project also gave New York City Transit the ability to extend the Brooklyn G line service in future.