Vista Verde Community Association

Upcoming Events!

No events

Notes from 12/20/2012 Meeting with DPW in Redwood City
In Attendance
From Department of Public Works (DPW), County of San Mateo:
James (Jim) C. Porter, PE – Director
Joe LoCoco, PE – Deputy Director, Road Services
From Vista Verde and Los Trancos Woods:
Ross Edwards – Civil Engineer and Founder and Former CEO, WEBCOR
Mario Wijtman – Commercial/Industrial General Contractor and EVP, XL Construction
Anne Baldwin – Resident since 1960 with property bordering Ramona Road
Ken Kormanak – Software Engineer (Secretary for Meeting)
William (Bill) Sloan Coats – Partner, Kaye Scholer, LLP
Ruth Thor Nelson – Co-Chair, SARR
Amanda Lee - Co-Chair, SARR and Co-Chair, VV Roads Committee
Summary
In a meeting with the DPW representatives, members of the ad-hoc Save Alpine and Ramona Roads Committee (SARR) met for about an hour at their office in Redwood City. The County heard the committee’s concerns and recommendations about the need for immediate action on the hazardous condition of the two roads that are in danger of collapse. The County said that, based on their visits to both roads, they had solutions which could be implemented this coming Spring and Summer to control the erosion conditions from further deterioration and stabilize them for normal use. Joe LoCoco will provide ongoing updates regarding permitting and general status for both projects to SARR Co-Chair Amanda Lee, who will in turn update the Committee and the VV/LTW communities.
The following two sections describe in more detail the discussion and recommended actions that the County plans to take.
Ramona Road
Ross Edwards described the situation at the edge of the road, which was built in 1966, as in danger of imminent collapse and recommended lagging with steel I-beams as the solution for shoring up the road (the same solution as was used on Ramona just downhill of the current slide area). Ross said that this action would avoid much more costly repair should the road fail during this winter season.
Jim Porter said that in his opinion the damage seen at Ramona Road was not significantly worse than other road slides he has seen and successfully repaired in the County and that he would not recommend the more costly soldier beam approach to the repair. He does not foresee any catastrophic failure to the road based on the lack of any large cracks in the road surface being evident at this time. His recommended action is to enlist his DPW road crews in the Spring, when the soil dries out, dig a key (a trench) at the base of the slide bench and fill with boulders (larger at the base, smaller near the top). Landscape fabric, topsoil and ground cover seeding would be applied to the slope to help stabilize and minimize erosion. Jim felt that this work using a 5-man DPW crew would take about a week and cost approximately $35,000, not including the field study, permits or materials that he felt would be inexpensive. A biologist’s field survey would be required and minor permitting which Joe LoCoco will initiate. Both Joe and Jim felt that the process will be straightforward and that construction could begin this spring (April, possibly May if a wet winter).
Jim guessed that the more extensive soldier beam solution, as suggested by Ross, might cost in the area of $500,000. Jim allowed that a soldier beam system would be optimal, but that it is simply not economically feasible to apply optimal fixes County-wide. He noted that the BAGG Engineering solutions per their report (commissioned by the LTC Water District) are designed to the highest engineering standards of withstanding saturated soils in an 8.0 earthquake but that, in this case, the most cost effective approach is the proposed surficial erosion control measure, an alternative that the
DPW currently feels should provide adequate erosion control and stability based on similar work done in the County. He also said that, should this alternative end up not working, then the County would proceed with a soldier beam installation.
Ross thought a soldier beam solution would cost significantly less than $500K and that he was waiting to hear from an engineering associate, Erwin O’Toole, for a quote. Jim cautioned that other costs make up his estimate including design plans, reviews and permits. Jim suggested that Ross speak with Soil Engineering Construction (SEC), owned by Bob Mahoney, a local firm that the DPW uses regularly for engineered projects, to get their estimate of cost and effort. (Note: SEC installed the existing soldier beam wall on Ramona downhill from the current slide area.)
We discussed that there are many utilities in the road and that failure to the road could cause catastrophic damage to the utilities and a huge inconvenience to the residents. Jim stated that the County does not have an obligation to provide a stable road bed for the utilities. We inquired about the possibility of PG&E contributing to the repair as it has power and gas in the road. Jim said we could try but "good luck".
Jim explained that funding for the rock stabilization fix would come from the annual roads budget requiring no additional approval. Funding for a soldier beam wall project would come from a Capital Improvement budget requiring budget allocation and project approval by the Board of Supervisors. Also, a soldier beam project would be competitively bid in accordance with the Public Contract Code, which will likely yield different bid prices than if simply negotiated with an individual company. Note that all estimates mentioned are ‘construction only’ bids that do not including design, permitting, testing, inspection, environmental monitoring, and a 10% contingency.**)
Post Meeting Update: Ross received a call from Erwin O’Toole of Granite Excavation Company with a quote of $140,000 (this bid is ‘construction only’ – see above**) for installing a soldier beam solution on Ramona comprising 80 lineal feet of retaining wall, excluding geotec report and permits. Mario Wijtman concurred that $140K is reasonable by taking the unit cost for soldier beam and lagging system at $50/sf SFCA and doubling it for the public works factor. Mario further felt that the cost of a bench and rip-rap fix would be at least 2 times the $35K mentioned.
Update as of 12/31/12: Ross and Ken Kormanak met with Bob Mahoney, SEC President/Founder, on 12/24 to review the Ramona site. They shared the BAGG Engineering report that includes geotechnical information obtained from core sampling done at the Ramona slide area and a rendition of a soldier beam solution. Bob responded that he feels an earth and rock fix will be more expensive than a soldier beam system and that a soldier beam system is a more positive fix. Bob will further review the report and quote a design-build engineered system.
Update as of 1/2/2012: $139K Soldier Beam Quote from SEC/Soil Engineering Construction
This bid is ‘construction only’ – see above**.
Email sent from SEC to Ross & Amanda: Since meeting at the site I have reviewed the BAGG Soil Report and have prepared an estimate for doing slide repair work in the zone that we talked about - 80 LF of repair in the area between Borings 2 and 3 as shown in the Soil Report. We talked primarily about repairing the slope by grading beginning lower down the slope and alternatively constructing a soldier beam wall with tiebacks and lagging at the top of the slope. Our preliminary analysis leads us to the conclusion that the soldier beam wall would be most appropriate both from the standpoint of economics and from the technical future performance aspects. Our estimate for constructing the soldier beam wall, including design and satisfying the design recommendations of the soil report is $139,000. This does not include the cost of permitting or environmental issues. We will look forward to hearing from you.
Upper Alpine Road
Amanda described the two slide locations on Alpine Road near the intersection of Joaquin. She noted the steepness of the road at these locations and the close proximity of Corte Madera Creek to the slides. Jim said that these slides would also be worked on in the spring. For a portion of this area he recommends “soil nailing” because the slope is comprised of native soil and there is solid material to hold on to. Soil nailing is accomplished by driving large steel “nails” around 30’ in length into the side of the hill with equipment that can hang over the side of the road. Wire mesh would then tie the nails together and cement slurry would be sprayed over the surface to provide more stabilization and waterproofing.
Jim said that, due to the creek’s proximity to Alpine Road, it is a more biologically sensitive area and he would need to start the permitting process with a number of relevant agencies to obtain their approval and let them begin their survey work. Jim said he would have Joe start the process to obtain the necessary permits. Jim was confident that this project could be started by this summer.
Jim said that there is money readily available for soil nailing from Road Funds (dollars collected from the State gas tax) as long as the project stays below $4.4M, which he felt would most certainly be the case. Due to the specialized equipment and design work involved, the nailing solution on Alpine Road will be done via a separate contract with an outside vendor.
The second slide further down Alpine Road is best fixed using a rock fill solution as described for Ramona, which can be installed by the DPW. Funds for this would come from the annual roads budget. Again, Joe will initiate the biologist’s field survey and any required permitting. This project start date estimate is by this spring and/or summer.
When asked why soil nailing could not be used for Ramona Road, Joe explained that Ramona is a cut-and-fill road and nails would only find fill in the top 25’ under the roadbed which would not provide good holding force.
Additional Discussion
Joe LoCoco explained that the culvert and collection box on the up slope side of Ramona Road near the slide had two pipes running under Ramona Road. One carried water to the collection box on the down slope side near Bjorn Conrad’s house. There was another at the bottom of a deep concrete box that had drain rock at the bottom to act as a catch basin for underground water seeping from the hillside. This was put in place when the road was constructed to relieve and channel water from seeping under the road. Ken Kormanak told Joe the corrugated drain pipes that carried water from the down slope side of Ramona Road to Los Trancos Creek were broken due to earlier slides and were no longer carrying water directly to the edge of the creek, but letting it out somewhere mid-way between the elevation of Ramona Road and Los Trancos Creek. Joe agreed to visit the site when he was available after the second week in January. Ken will contact Joe at that time to set up a time to view the condition of the drainage pipes.
______________________________________________________________________________ VV/LTW Committee to Save Alpine and Ramona Roads (SARR) This email address is being protected from spambots. You need JavaScript enabled to view it.
Amanda Lee/SARR Co-Chair and VV Roads Committee Co-Chair/650-851-1677, Ruth Thor Nelson/SARR Co-Chair/650-851-3546, Steve Friedman/LTW CERPP Coordinator, Ken Kormanak, Ross Edwards and Mario Wijtman. Committee formation approved by: Tom Thayer/LTWCA President, Deb Smith/VVCA President, Autumn Stanley/LTWCA Board Member and Bill Tagg/VV CERPP Coordinator.
Mail: SARR c/o Ruth Thor Nelson, 354 Ramona Road, Portola Valley, CA 94028