What’s Going On Inside That Big White Tent on Cesar Chavez?

Someday, Cesar Chavez Boulevard will be a glamorous, tree-lined thoroughfare equipped with clever design touches that allow cars, bikes, and pedestrians to share the street safely and efficiently. But today is not that day. Today, Cesar Chavez is a gnarled maze of traffic pylons, heavy equipment, and congested traffic. Yet amid all the construction chaos, one new feature is rather conspicuous: a large white tent that was recently erected at the intersection with Florida Street.

For residents of Bernalwood’s north side, the purpose of the tent has become the object of much conjecture and speculation. Some say the the tent will serve as the venue for a Teatro ZinZanni-style pop-up dinner theater, with the menu selected and prepared by chefs from the Hillside Supper Club. Others cite rumors which say the tent will play host to the bar mitzvah reception of young Herbert Schwartzmann of Peralta Avenue, who requested a “Bob the Builder” theme.

Fellow citizens, your Bernalwood investigative team is here today to tell you that those theories are incorrect. The truth of the matter is that the tent shelters the access point for a high-tech effort to stabilize the subterranean 19th century sewer pipe, which was recently supplanted by the brand-new pipe installed on the north side of the street.

The stabilization effort uses a technology called Cured-In-Place-Pipe (CIPP) that involves stuffing giant, resin-impregnated felt tubes into the old old sewer pipe. You can see a pile of the felt tubes stacked up here:

The felt tubes are become solid when they are cured with hot water, which stabilizes the old sewer pipe — eliminating the need to dig up the street to remove it.

Here’s an explanation of the process from the website of Sak Construction, which is performing the work on Cesar Chavez

During the wet-out process, the felt tube, coated on the outside with a continuous impermeable layer of polyurethane, is resin-impregnated, fully saturating the felt so that no voids or pockets of air remain in the tube. The wet-out liner is inverted into the existing pipe using a hydrostatic head or pressurized air. As a result, the resin-saturated side of the liner interfaces with the wall of the existing pipe. The reverse side of the liner—which is coated with polyurethane—thus becomes a smooth interior surface to effectively carry the rehabilitated pipeline’s flow.

Once the liner is in place throughout the entire length of the pipeline that is being repaired, we inject hot water or steam to cure the liner resin. When properly cured, this provides a continuous, jointless “pipe-within-a-pipe” and restores structural integrity to the damaged pipe.

This video shows how all the pieces come together:

PHOTOS: Courtesy of @SomaFMRusty

24 thoughts on “What’s Going On Inside That Big White Tent on Cesar Chavez?

  1. As a San Franciscan I am particularly grateful that Saks is using ORGANIC peroxide during this process….

  2. Thanks for posting. This explains the horrible fumes I’ve been smelling over the past few weeks as I pass this spot on Cesar Chavez. Is it the solvent they are using? Styrene fumes? Can’t imagine working there every day…. or living in front of this work site.

  3. Quick google search with “cipp installation fumes” suggests that it is styrene. But apparently I shouldn’t be alarmed, I’m just sensitive….. From an FAQ for a similar project in Hagerstown, MD: “You may smell these styrene fumes while the lining contractor is working in your area, but don’t be alarmed. Humans detect styrene odors at a concentration of approximately 0.017-1.9 parts per million (ppm) which is well below the permissible limit of 100 ppm for the work place (8 hours per day, 5 days per week).” At least I know what it is now.

  4. I was going with the Circus, but thank you for the real explanation- that’s pretty amazing technology. Wish I could do that with MY sewer line. maybe I can…

  5. Thank you for this! Every time we drove by we wondered what was going on! Did not come close to guessing the real explanation.

  6. The fumes from that tent smell like someone just vomited. I walked past it this morning and kept checking my shoes as it seemed like I had stepped in something.

    When they started digging up Chavez in earnest for this project, it seemed like every mouse within a 2 mile radius took refuge in my house (I live up the hill a few blocks on the North Slope). Never had mice before that.

    Despite all this, I’m really looking forward to the “New Cesar Chavez,” it’s going to be way better than what it is today. Anyone want to make a bet on the completion date?

  7. Thanks.. this clears things up. I had thought they were removing the ancient sewer and replacing it with the new one, but I guess they are building the new one parallel with the old. Is the relining of the old sewer being done to keep it in use, or to simply reinforce it so it won’t collapse under the roadway?

    • The latter, I was told. The lining is structural reinforcement, to ensure the old sewer will not collapse (and create sinkholes). Apparently, this technique is vastly cheaper than trenching to remove and fill the old sewer pathway.

      • That’s a pretty clever use of the product. They advertise it for re-lining sewers for continued use, but if the stuff’s strong enough to keep the pipe intact, I can see how it would be vastly cheaper than removing the old sewer and bringing in fill material, etc.

  8. Wait, let’s get the story straight. The street is being dug up to add a new sewer, and all the new tech reinforcement is to save digging up and replacing the old one? Why is there no information from the powers that be who are doing the work? If the street is dug up again in three years will Pipetech (whatever) pick up the tab?

  9. I was just about to order my Rosh Hashana tickets for this hot new pop up synagogue.

  10. Any info on the lining material of the new pipe, i.e., will it leach toxic chemicals into the water?

  11. Anyone else smelling the polyurethane smell INSIDE their houses? I have no idea why that is, but sometimes it’s so bad I have to open the door and turn on the air purifier and cover my face while I sleep.

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