San Francisco transit officials are hiring a contractor to fix the water leaks in the Central Subway’s Chinatown-Rose Pak station. The work to mitigate the water intrusion will require a 17-day closure of all four stations of the Central Subway next year, transit officials outlined in a presentation last week.
The San Francisco Municipal Transportation Agency (SFMTA) Board of Directors on Dec. 3 approved a nearly $6.5 million contract with the firm Renseco Inc. to mitigate the ongoing water intrusion at the Chinatown-Rose Pak station. The work will take place next year from Feb. 26 to March 14. Transit officials said during the work period there will be no T-Third serving the Central Subway stations. Muni passengers instead will be told to take the 30-Stockton or 45-Union/Stockton as alternatives during the closure of the Central Subway.
Albert Hoe, the Central Subway program manager, told directors that crews will perform three different methods to plug the water leaks in the Chinatown station. He said that Renesco plans to inject a “slurry or cementitious base into port holes” will seal the cracks where from the water is leaking and push the water out. Other methods used to seal the cracks include using chemical grouting to seal small cracks.
“With these two hybrid options, we believe this gives the best chance to mitigate and take care of any of the Chinatown station water mitigation efforts that we need to sort of go forward,” Hoe said.
A third method being used is to inject grout on the floor to seal joints and cracks. Hoe described it as “sewing the crack together with grout.”
Panels are rusted and water is leaking onto the one of the staircases between the platform and concourse levels.
Hoe said the water leaks were first noticed toward the end of constructing the station when crews noticed water intrusion at the southern crossover cavern. The SFMTA at the time asked the contractor to mitigate the water intrusion using a yellow waterproofing membrane, which had already been installed throughout the different sections of the station.
Crews were successful in fixing the water leak at the southern cavern. However, Hoe said he believes that the water moved and is now in the platform cavern and also into the head house of the station. Damage from the water leaks is noticeable at the station where panels are rusted and water is leaking onto the one of the staircases between the platform and concourse levels.
Director Steve Heminger questioned Hoe on who would pay for the repairs and if the agency would submit a claim to the main contractor, Tutor Perini. Hoe said the agency already approved a global settlement agreement with Tutor Perini in accepting the work and closing out the contract.
Hoe said that funds for the repairs will come out of the agency’s capital reserve budget that was set aside for finishing the Central Subway. The reserve has approximately $29.4 million, Hoe said. He added that there is a warranty on the work and he is working with the City Attorney’s Office in seeking other avenues beyond Tutor Perini.
Other work happening at the Chinatown station includes installing new artwork on the plaza level, which should be completed before the Lunar New Year. Additionally, Hoe said there will be a display of artifacts that were found during the excavation of the station, such as an old sewing machine.
