Update on SFD Blvd. Lane Closure

Posted on January 10, 2022


1/10/22

Update as of this morning, from our Interim Public Works Director, Jonathon Goldman:

Work continues on the emergency repairs resulting from the December 13th sinkhole discovery.  Work remaining to be completed includes:

  • A second layer of structural connection between the failed unreinforced concrete wall and the steel sheet pile wall,
  • backfilling of the excavation,
  • forming and pouring of a replacement pedestrian sidewalk (owing to its importance as a route serving Oak Manor and White Hill schools),
  • thrie-beam guardrail re-installation, and
  • fencing reinstallation.

Maggiora & Ghilotti will grind and place finish grade asphalt and restore pavement markings once the last of the work necessitating lane closures has been completed.  The weather forecast is good.  Subcontractor availability is becoming an issue but we are continuing to emphasize the need to get work completed quickly.  I now anticipate that all work will be completed by January 19th.   I recognize that having the lane closed and the traffic signals flashing red remains an inconvenience but every hour of work that can be completed during the workday is an hour sooner that all of the traffic restrictions can be removed and traffic flow for vehicles, pedestrians and bicyclists can return to normal.

1/5/22

Update as of this morning, from our Interim Public Works Director, Jonathon Goldman:

A brief status update on our sinkhole repair project.  Curb and gutter were poured yesterday.  Asphalt is being laid and compacted today but will not be the finished surface – BUMP AHEAD signage will be placed.  The plastic K-rail traffic barriers will be moved from the center line to the lip of gutter and filled with reclaimed water later today.  The plan is for the robotic one-lane traffic flagger lights to be turned off and the Creekside eastbound lane of SFD temporarily re-opened to traffic at the end of the workday today.  The traffic signal at Oak Manor will remain on three-way flash to continue to calm traffic and prevent conflict with the flagger signals when they are operating.  One-lane traffic will be reestablished during the work day tomorrow and for several more days while additional work is completed including:

  • completing the structural connections between the failed unreinforced concrete wall and the steel sheet pile wall,
  • backfilling of that excavation,
  • forming and pouring of a replacement pedestrian sidewalk (owing to its importance as a route serving Oak Manor and White Hill schools),
  • thrie-beam guardrail re-installation, and
  • fencing reinstallation.

Maggiora & Ghilotti will grind and place finish grade asphalt and restore pavement markings once the last of the work necessitating lane closures has been completed.  Weather and subcontractor availability permitting, I anticipate that all work will be completed by January 15th.

 

12/30/21

Update as of this morning, from our Interim Public Works Director, Jonathon Goldman:

The helical anchors have been installed, steel sheets are being welded over the gaps in the new sheet pile wall and the steel walers are expected to be installed by the end of day tomorrow (Friday).  Paving and curb and gutter construction are somewhat weather-dependent but planned for early next week.  The closed lane will be open (once paved) when work is not being performed but the lane will be closed when the connection between the new wall and the old one is being made and for construction of sidewalk and the necessary fencing.

 

12/22/21

Update as of this morning, from our Interim Public Works Director, Jonathon Goldman:

Sheet pile installation was completed yesterday before any significant rainfall.  The site was prepared for today’s activity which is primarily the installation of helical anchors that will be drilled under the roadway to tie back the sheet piles.  The helical anchors will pass above the fiber optic cable under the work site, and well below the gas and water mains located on the easterly side of SFD.  Those lines have been marked and will be exposed by vacuum excavation to ensure that they are not so deep as to potentially conflict with the easterly ends of the drilled anchors.  The anchors will not extend past the limits of the public right-of-way.

The steel walers (“C-channel”) delivered for the tie-backs to pull against, and to bolt onto the failed concrete wall, were not what was ordered.  The correct material is being picked up in Stockton and delivered later today or first thing tomorrow (Thursday).  It is anticipated that the sheet pile wall will be tied back and steel plates welded to prevent backfill from being eroded away at the end of the day Thursday or Monday morning.  Because the roadway cannot be open by Christmas, I have asked that no work take place Christmas Eve, Christmas Day or Sunday the 26th (Kwanzaa).  This will allow the construction workers, who have worked every day since the 13,th some time for their families, make their work safer when they return, allow our supply chain to catch up, and hopefully allow weather conditions to warm up enough for hot mix asphalt paving to take place during the week of December 27th through the 31st.

 

12/20/21

Crews have been working through the weekend to secure the roadway at or near 2378 Sir Francis Drake Blvd. Our Interim Public Works Director, Jonathon Goldman, has provided the following update:

At end of workday Sunday we were halfway across the span of driven steel sheetpiles being installed to create new roadway support separated from the old unreinforced concrete retaining wall that we found undermined last Monday.  We expect to have the sheetpile wall completely driven by the end of shift Monday or early Tuesday which will significantly protect us against any subsequent intense rainfall.  The National Weather Service forecast as of 4 AM Monday is for a quarter to a half an inch of rainfall possible beginning Tuesday morning, another quarter to half an inch Tuesday night, and another quarter to half an inch possible on Wednesday.

Once the sheetpile protection is completed, little or no new erosion of the roadway subgrade is likely even if the creek rises significantly.  Helical anchors and steel walers will be installed to tie the sheetpile wall back into the soils underlying the unaffected portion of Sir Francis Drake Boulevard.  They will not extend as far as the natural gas and water mains buried on the easterly side off the roadway and they will drilled in a manner that will avoid damaging the fiber optic cable buried under the lane that is currently closed.  Steel vertical “C-channel” supports will also be installed to prevent any further independent movement of the sections of the failed unreinforced concrete wall.  The stability of the failed section of the wall benefitted from the placement of rock support below the wall during the first phase of repair.  Once the tie-backs and walers have been installed and tensioned, the roadway sugbgrade will be backfilled and prepared for paving as well as curb and gutter constructed to prevent runoff from penetrating into the subgrade.  If feasible, temporary sidewalk access (primarily due to the importance of this route for school children once schools reopen) will be installed with a suitable guard, wheelchair and cane-detectable edge protection (likely a 4-inch vertical curb at the back of walk).  If it is not feasible to restore pedestrian access, the sidewalk will remain closed until a permanent repair can be completed.  Paving and pavement markings will be completed as weather permits with the objective of restoring full traffic flow as soon as possible.  At this time, that is forecast for the end of the week – Christmas Eve.

– Jonathon Goldman

Storm Update (12/13/21)
The rain is back! While we are all grateful for this much needed water please be careful and prepared. Rain is expected to continue into Tuesday. The total rainfall depth forecast is between 3- and 5-inches over the storm event here in Fairfax. Maximum wind gusts across Marin valley floors are forecast to reach up to 30-40 mph with elevated terrain gusts forecast to exceed 55 mph.  PG&E recommends that we all prepare for sustained power outages that may be caused by vehicles into poles, branches/trees or other debris into wires, earth movement, etc.
Prepare for stormy weather in advance with PG&E safety tips.
Please use this link to check for Outage location and estimated times of restoration: Current and Future Outages
Avoid This Area If Possible
We have a failed retaining wall at the 2300 block of Sir Francis Drake that requires an emergency repair.
There is a massive void under the sidewalk and at least a part of the eastbound lane, that appears to be at least 15-feet deep. The roadway could collapse literally at any time as the creek flow continues to wash out dirt from behind the wall and under the road.
Based on our Public Works Director, Jonathon Goldman, and our Town Engineer Mike Jewett, of Miller Pacific, the retaining wall is an imminent threat to life and property, requiring the Town the close down one lane of traffic on Sir Francise Drake BLVD. Construction equipment is staged and ready to start work tomorrow morning at 8 AM. The project may take up to 2 days to complete but depends on what the engineers find once they open up the roadway.
Please plan to avoid the area, if possible, over the next few days.
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