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| More work to be done on 4th Av line structural rehab tunnel project; express track closure til 2020? (1508060) | |||
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More work to be done on 4th Av line structural rehab tunnel project; express track closure til 2020? |
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Posted by gold_12th on Sun Mar 24 10:42:01 2019 This retroactive modification, which was the subject of a notification memo to Board members in February, is for additional steel repair/replacement as part of the ongoing 4th Avenue Line Subway Tunnel Structural Rehabilitation project from 39th Street to 60th Street in the borough of Brooklyn.The project scope, which was based on visual noninvasive inspections, includes removing and replacing 312 corroded steel columns and connection elements; repairing approximately 325 roof beams; painting of all structural steel; repairing/rebuilding cracked concrete floors; and sealing of all active water leaks with chemical grout. The work also includes raising the level of the street ventilation gratings, providing them with a more robust and better drainage system; and reconstructing the roadway curbs along 4th Avenue to accommodate the new drainage system. This section of the 4th Avenue line was constructed between 1909 and 1915 and consists of four tracks. Ventilator gratings located above the express tracks along the median of 4th Avenue allow air to flow between street level and the subway system. Because the gratings sit flush with the median, just a few inches above street level, the tunnel is often exposed to rain and snow runoff which is often laden with corrosive roadway deicing salts. The ventilators include a drip pan system to prevent the runoff as well as dirt and debris from reaching the subway tracks. This drip pan system has been rehabilitated several times over the life of the tunnel; it is often clogged, allowing accumulated salt-laden water to pour into the tunnel structure. More than a century of exposure to these elements has taken a toll on the tunnel’s structural elements in the immediate vicinity of the ventilator gratings. Post-award surveys of the roof beams that involved removal of concrete encasement immediately adjacent to the ventilators showed that the steel deterioration was more severe and pervasive beneath the concrete than anticipated. As a result, contractual quantities for steel repair are insufficient to address the extent of repairs required within the contract limits. This state-of-good-repair modification is for more of the same repairs specified by the base contract, and includes replacement of an additional 44 columns and repairs to 401 additional roof beams, all within the contract limits. In order to complete this additional work within the existing express track shutdown, the acting SVP, Capital Program Management approved a retroactive waiver on February 15, 2019, authorizing the immediate commencement of work. Additionally, this modification requires that the additional work be performed during two 12-hour shifts, seven days a week. The contractor’s revised proposal was $32,954,750. The revised in-house estimate is $21,100,000. Negotiations resulted in the agreedupon lump-sum price of $23,040,000 and no impact to the project schedule. Savings of $9,914,750 were achieved. This price is found to be fair and reasonable. Vendor Name (Location): El Sol Contracting/ES II Enterprises, JV (Maspeth, New York) Contract Number: C-33835 Description: Subway Tunnel Structural Rehabilitation, 39th Street to 60th Street, 4th Avenue Line, B Division (BMT) in Brooklyn Contract Term (including Options, if any): May 18, 2017–March 17, 2020 Additional Work Order/Modification: #4 Current Amount: $ 61,630,550 This Request: $23,040,000 page 181; http://web.mta.info/mta/news/books/pdf/190325_1030_Transit.pdf |
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