Mountain View, California
CE&G provided geotechnical engineering services for resurfacing of 6 miles of the San Francisco Bay Trail between Google’s headquarters in Mountain View and Highway 237 in Sunnyvale. The trail is situated atop existing levees owned by United States Fish and Wildlife Service’s Don Edwards San Francisco Bay National Wildlife Refuge and Santa Clara Valley Water District, and is surfaced with gravel. The trail is to be resurfaced with additional aggregate base as required to support PG&E maintenance vehicles and then capped with a smooth aggregate wearing course consisting of stabilized quarry fines. Work included site reconnaissance, 12 shallow hand-dug test holes, laboratory testing, engineering evaluations, and conclusions and recommendations for resurfacing of the trail and stabilizing eroded levee reaches.
SF Bay Trail, Crockett to Martinez, Martinez, California
As a consultant to Contra Costa County in 2002, Cal Engineering & Geology provided the geotechnical engineering, preliminary civil design, and planning services for the conversion of the 1.7 mile long abandoned section of Carquinez Scenic Drive between Ozol and Port Costa in Contra Costa County. The section of the road, which was being studied, was abandoned by the county in 1983 following the development of several large landslides which made the road impassable. The geotechnical investigation completed for the project included drilling of 14 exploratory borings, laboratory testing, geologic mapping, and preparation of a preliminary geotechnical report. The Design Alternatives Report provided conceptual level alternatives for addressing the geotechnical hazards along the road. Site specific and generalized typical details for repairs consisting of tieback retaining walls, geogrid reinforced embankments, stabilization piles, soldier beam and lagging walls, and pavement stabilization were developed and presented with preliminary engineer’s estimates.
In 2011, Cal Engineering & Geology was once again retained to provide geotechnical engineering and value engineering services on the project, this time as a subconsultant to the East Bay Regional Park District, who would develop the final design and construct the federally funded trail. CE&G was involved in the value engineering process to assist the design team to optimize the trail configuration at the large landslides. The supplemental geotechnical investigation completed for the project included drilling of 26 additional exploratory borings, laboratory testing, geologic mapping, and preparation of a design and materials report in Caltrans format complete with Log of Test Boring sheets. CE&G recently provided observation of pile drilling for debris walls and retaining walls.
Memorial Park Trail Near Mission Boulevard, Hayward, California
CE&G provided full design, PS&E, value engineering, and construction observation and testing services to the Hayward Area Recreation District (HARD) for two portions of the Memorial park trail damaged during intense storms. At both sites, the trail width had been reduced by creek bank failures and resulted in designs which were bid, but exceeded available funding. CE&G developed alternate designs and prepared plans and technical specifications to improve constructability and reduce cost. Both projects were approved by FEMA for funding and later constructed. At one site, the repair consisted of a geogrid reinforced segmental block retaining wall supported on a pier and grade beam foundation while at the other site a wood lagging and steel beam retaining wall was used. The project required coordination with HARD and the City of Hayward due to a sewer line located within the trail. For both projects, CE&G also completed construction observation and testing services for the trail stabilization measures including: review of contractor submittals, phone and email communication with the District and the contractor’s representative, part-time observation of the pile hole drilling operation, concrete testing, observations of wall construction, preparation of progress letters, and preparation of a final construction report.
Snell Street, Oakland, California
Cal Engineering and Geology completed geotechnical studies and pavement design for the City of Oakland Public Works Agency in support of the City’s 7th Street West Oakland Transit Village project. The heavily traveled roadway had been modified and overlayed numerous times in the past 100 years. As a result, highly variable subsurface conditions existed over the ½ mile stretch of the project. CE&G coordinated with the City traffic and utilities departments, and with various outside utilities to select acceptable subsurface exploration sites. The work included more than 10 pavement corings and two geotechnical borings, and the preparation of a geotechnical and pavement design report. The report also included geotechnical design recommendations for gateway and cantilever entry structures to be constructed as part of the project.
Rancho Rio Avenue, Ben Lomond, California
CE&G conducted a geotechnical investigation and foundation report for the replacement of the Rancho Rio Avenue Bridge over Newell Creek located in Ben Lomond. The existing bridge was approximately 39 feet long and 12 feet wide. The bridge superstructure consisted of steel girders with a concrete deck and was founded on reinforced concrete abutment walls that were supported by spread footings. The bride deck surface was approximately 12 feet above the bottom of Newell Creek. The planned project consisted of a new two lane bridge to be approximately 48 feet long and 29 feet wide. The bridge deck profile was planned at an elevation of approximately 29 feet and founded on CIDH pile-supported reinforced concrete abutment walls.
N. Livermore Avenue, Livermore
CE&G completed a foundation report for the new, recently completed 10 ft wide, 160 ft long pre-fabricated pedestrian bridge over North Livermore Avenue. The planned pedestrian bridge was to consist of two or three spans of steel trusses with wood or concrete decking supported on concrete abutments. CE&G also completed geologic research of the site and vicinity, drilled three exploratory borings in the vicinity of the planned abutments and bents, coordinated development of traffic control plans with the City, and prepared a foundation report in Caltrans format including Log of Test Boring Sheets.
Zander Dr, Orinda, California
Zander Drive Landslide is a large historic slide in Orinda, California that extends approximately 1,000 feet west of Zander Drive to San Pablo Creek. After several episodes of slide reactivation in the 1960s, 1980s, and 1998, the City of Orinda took possession of two private properties located within the headscarp area of the slide.
In 2006, Cal Engineering & Geology was retained by the City to study the upper portions of the landslide in detail, and determine the feasibility of constructing engineering improvements to stabilize the landslide. CE&G evaluated the previous geotechnical work completed regarding the landslide over the past 40 years, and completed an extensive subsurface exploration, instrumentation, monitoring, and testing program to characterize the landslide. Several potential stabilization concepts and estimates were developed, evaluated, and presented to the City. Complete stabilization of the 100+ foot deep landslide proved to be unfeasible. In lieu of complete stabilization, the City chose CE&G’s design, and implemented affordable headscarp drainage improvements and a long term maintenance program.
Wildcat Canyon Roadway, Richmond, California
After unusually heavy El Nino rainfall in 1998, significant movement occurred along a 230-foot long section of the Wildcat Canyon roadway embankment located approximately 0.72 miles west of the intersection at San Pablo Dam Road. At that time, distress to the pavement was repaired by Contra Costa County with an asphalt concrete overlay. Continued movement of the embankment resulted in more cracking and vertical offset of the asphalt concrete pavement in an arcuate pattern crossing both traffic lanes. The pavement cracks were surveyed by the County immediately prior to placement of a second asphalt concrete overlay in 2001. A similar cracking pattern eventually appeared through the overlay. In addition, a 25-foot wide by 35-foot long relatively shallow slump of the embankment slope occurred with slide debris extending down to the embankment toe. The movement of the embankment resulted in the closure of the west-bound land of Wildcat Canyon road at two locations in 2001.
Cal Engineering & Geology was retained by the Contra Costa County Public Works Department to complete a geotechnical subsurface exploration and report for the two landslide areas. Geotechnical borings were drilled and sampled, laboratory soils testing was completed and a geotechnical report was prepared. The report included design alternatives analyses, detailed conceptual designs, and cost estimates. The selected repair consisted of a cast-in-drilled-hole soldier pile and concrete lagging retaining wall with tieback anchors.
Vasco Road, Livermore, California
For years, a dangerous stretch of road plagued the motorists who used Vasco Road, a formerly rural road that serves as a major commute route from east Contra Costa County. Cal Engineering & Geology was retained by the Alameda County Public Works Agency to provide geotechnical consultation and design services in conformance with the Caltrans federal aid process for the realignment and safety improvements of approximately 1 mile of Vasco Road just north of Livermore and south of the County line. The geotechnical aspects of the project included excavations up to 100 ft high through highly sheared and faulted bedrock and construction of embankments up to 82 feet thick.
At the request of the County, CE&G prepared earthwork specifications and designed and prepared the plans and developed specifications for the large cut slope with horizontal drains, a 45 foot tall segmental block retaining wall, and several other temporary retaining structures. CE&G also provided engineering, construction observations, and testing in support of the ACPWA Construction Division throughout the construction of a required 1.75 mile, PG&E gas pipeline relocation project ($4 million construction), and during the construction of the actual road project ($12 million). Due to the relatively high anticipated construction cost estimate, the project underwent the Caltrans-mandated value engineering review process. The results of the process concluded that there were no further opportunities to enhance the design. After completion of the project, the Alameda County Public Works Agency was given the National Roadway Safety Award in Washington D.C. by the Roadway Safety Foundation and the Federal Highway Administration for the County’s efforts to reduce fatal crashes through collaborative planning and execution of the project.
In 2004, Cal Engineering & Geology was retained by the Alameda County Flood Control District to complete a subsurface exploration and prepare a geotechnical design report for the trenchless pipe jacking installation of a new 8 foot diameter concrete culvert adjacent to an existing culvert that passes beneath the Union Pacific Railroad (UPRR) yard in Union City. The work required extensive coordination with UPRR and the District during subsurface exploration. The geotechnical exploration project also incorporated environmental sampling to assess the potential contamination of soils through which the pipe would be jacked. Geotechnical design recommendations for the jacking pit shoring were also provided. The project was designed by District staff and was constructed successfully.