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Past Projects
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· Pulgas Valve Lot Upgrade
This work, located in Redwood City California, isolation valves with by-passes are to be installed in each of the 4 Bay Division Pipelines. There will be two valve vaults each containing two isolation valves and ten by-pass valves with concomitant pipe. Butterfly valves with actuators to install range from 18" to 72" in size.
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· University Mound
This work for the San Francisco Water Department consisted of removing existing and replacing two sections of 48" diameter steel University Mound water transmission pipeline on existing concrete saddles inside a utility tunnel under the I-280 freeway in San Francisco. The project included renovations for the South Basin which was built in 1937. The University Mound Reservoir supplies nearly one quarter of the San Francisco's drinking water. The scope of work included concrete repair of spalled and corroded roof slab soffit; cleaning, repair cracks and construction joints and sealing of the reservoir roof; cleaning of the reservoir basin and removal of sediment; concrete repair of joists and beams inside the reservoir; replace expansion joints and protection covers; installation of sampling station; construct new concrete roof hatch and stair structure with aluminum rolling hatch cover. Mitchell Engineering also replaced existing louvers around perimeter of reservoir with new louvers or shotcrete infill; replaced 48" valve, spools and piping during a 24 hour shut down. The total length of pipe replaced was approximately 1,120 linear feet.
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· Crystal Springs Pipeline No. 1 - Replacement
This project was done for the City and County of San Francisco. The location was from Brisbane to Daly City in San Mateo County, CA. The Crystal Springs Pipeline is one of two feeder mains that supply 90% of the water needs for the City of San Francisco. The project consisted of furnishing and installing 2,000 lf of concrete lined tar coated 48" welded steel pipe, 1,800 lf concrete lined concrete coated 48" welded steel pipe, 1,500 lf of concrete lined 36" welded steel pipe for slip lining, constructing a vault to house a new venturi meter, 4,000 lf of removal and disposal of existing 60" steel pipe. The excavation and installation of the 2,000 lf of 48" steel pipe was situated in the middle of Bayshore Blvd., one of the heaviest traveled four lane roads in San Mateo County. With excavations up to 17 feet deep and pipe weighing in at 20,000 pounds, 40 feet in length, keeping a smooth flow of vehicular traffic was a challenge of its own. Mitchell Engineering completed the entire project with an excellent safety record.
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· Irvington Portal
Irvington Portal is a San Francisco Water Department facility located in Alameda County west of the City of Fremont. This facility consists of 4 butterfly valves installed in the Bay Division Pipelines downstream of the Irvington Tunnel. Mitchell Engineering was contracted to remove and install 3 valve actuators and 1 valve actuator valve with gear box. Minor electrical work was also accomplished at the Sunol Water Treatment Plant in Sunol, California under this contract.
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· Clarendon Pump Station
The work done in this contract consists of 3 phases.
1) The Clarendon Pump Station work is located at the corner of Laguna Honda Boulevard and Clarendon Avenue in San Francisco. This is an above ground pump station containing 6 centrifugal pumps and associated piping fittings and valves; motor control center and reduced voltage starters, electrical switchgear and station control panels; chemical storage tanks and metering pumps and diesel engine generator set with underground fuel storage tank.
2) Pipeline installation work includes 16" and 20" water mains along City streets from Clarendon Pump Station to Summit and Stanford Heights Reservoirs and portion of 36" steel pipe along Laguna Honda Boulevard.
3)Replacement of 1 pump and motor set, associated piping, starter and concrete pad in San Francisco Water Departments Lake Merced Pump Station.
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· Cherry Tunnel Rock Trap Rehabilitation
This project was for the City and County of San Francisco and Hetch Hetchy Water and Power. The project location was in Tuolumne County, California off Highway 120. The work on this contract consisted of removing rock and gravel from the existing rock trap to restore the rock trap to its original dimensions. The Cherry Tunnel is a dual purpose water supply and power generation tunnel. The tunnel is fed from Cherry Lake and feeds Holms Power House. The project consisted of a calculated power shutdown during the low demand for both water and power during the months between September and December. The purpose of the project was to clean out the unlined portion of the tunnel up to the lined portion. This was necessary to keep debris from the turbines at the power house. The rock trap was approximately 8,000 lf upstream from the penstock. An interesting fact on this project was that the tunnel was built in the 1950's and had no maintenance up to the point that Mitchell Engineering worked on the project.
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· Sutro Reservoir No. 2
The project is for the seismic retrofit erosion and drainage improvement. The scope is for new inlets, roof repairs and miscellaneous improvements. The work at Sutro Reservoir consists of the installation of 36" diameter concrete coated and mortar liner steel pipe, portions of which included pipe jacking at two locations into the reservoir basins; Two access hatches have been installed to provide small boat access for the Water Department in to the reservoir basins. Also included was cleaning and removal of existing roof surfaces, sealing of concrete cracks along with final sealing of the reservoir roof; Removal of existing louvers from the perimeter walls to the basins, some of which have been infilled with reinforced concrete while other areas are replaced with new steel louvers; A concrete vault has been constructed to provide for the installation of 30" butterfly valves and actuators. Removal of sediment form the bottom of the reservoir basins has also been performed as part of this project. Sutro Reservoir is located in the Twin Peaks area in San Francisco, California.
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· College Hill Reservoir
The work for this project consists of seismic retrofit and improvements at the San Francisco Water Departments College Hill Reservoir located at Elsie Street and Appleton Avenue in San Francisco, California. College Hill reservoir is the oldest reservoir in San Francisco pre-dating the Civil War.
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· Forrest Hill Tank Replacement
This project consists of the replacement of the Forrest Hill Street Tank located at Mendosa Avenue near 10th and Quintara Streets in San Francisco, California. Work consists of demolition of existing steel tank, attached piping and its concrete foundation, install new concrete foundation which includes building a new concrete ring on top of concrete piers and, to furnish and install new welded tank and accessories.
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· Sunol Valve X-20 Replacement
Alameda East Portal is a San Francisco Public Utilities Commission (SFPUC) facility and is located south of the town of Sunol in California. This work incorporated the removal and replacement of one 72" butterfly valve with actuator, the modification of
existing pipeline, and, removal of existing valve support and construction
of new valve support. This work was performed for the City and County of San
Francisco.
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· Ocean Avenue Reconstruction and Improvement Proj.
This project was for the Municipal Transportation Agency (MUNI) in San Francisco, CA. The Ocean Avenue Reconstruction and Improvement Project spans the distance between Juniper Serra Boulevard to San Jose Avenue (1.7 miles) which is one of the busiest throughfares in the bay area. One of the primary goals of this ambitious project was to improve overall transit services, and through the process, provide a fresh distinctive "look" to the commercial corridor and community along Ocean Avenue. The extensive infrastructure reconstructing and improvement project comprised of demolition of existing sewer and water lines; construction of new 10" to 27" VCP and RCP sewer lines; construction of new 4" to 12" DIP water lines; replacing and reconstructing MUNI track rails; construction of MUNI low level streetcar platform stops; reconstruction of existing streets and sidewalks along with associated landscaping; and reconstruction of existing overhead electrical system, street lighting and other electrical works. All the while, Ocean Avenue merchants were open for business.
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· San Pedro Valve
The San Pedro Valve Lot is a San Francisco Water Department site located in San Mateo County in Daly City. The installation consists of work on existing vaults, piping and valves. Under this contract one 42" gate valve and two 30" agte valves shall be removed; one 42" ball valve, one 42" butterfly valve, and twp 30" butterfly valves shall be installed. The existing valve vault shall be enlarged to encompass the new valves.
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· N, L, & J Lines Rail Replacement-Various Locations
This project was located in San Francisco, CA. The project consisted of rail replacement at various locations. Mitchell Engineering first replaced 4,700 track feet of tie & ballast track and 600 track feet of direct fixation track in a 60 day shutdown period. Additional trackwork included replacing 17 switches, in two "wye" turnouts, five crossovers and one turnout and their associated direct fixation trackwork consisting of a total of 5,600 track feet. Three crossovers were completed in weekend shutdowns and the "wye tracks" in 30 and 45 day shutdown periods. Additional work included overhead electric adjustments and miscellaneous pole replacements, sewer and manhole replacement in track replacement areas, boarding platform and shelter rehabs.
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· South Fork Bridge
This project is located along the North side of the South Fork Tuolumne River in Tuolumne County, California. General scope of work includes, construction of new bridge and abutments, removal of existing piers and foundations, construct new retaining walls and stone masonry wall, rebuild road and pave with concrete approximately 1400 feet of roadway, installation of storm drains and inlets and, repair of existing dirt road by grading, backfilling eroded areas and improving access to site.
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· Potter Valley Slope Stabilization Project
This project was located in Potter Valley, CA. and consisted of stabilization of an old landslide directly below the wooden stave penstocks. The project consisted of replacing 2 existing sheet pile walls located east of the penstock with longer and deeper sheet pile walls; installation of 60 lf long soil anchors in the hillside and attaching to sheet piles. Also included was replacing soil located between walls with free draining material. Construction of various surface and subsurface drainage facilities including 90 lf of subsurface horizontal drains.
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· 3rd Street Light Rail - Overview
Mitchell Engineering has received five segments of the 3rd Street Light Rail Project as a general contractor and one segment as a subcontractor. As a general contractor, Mitchell has the following segments: The 4th Street Bridge, King Street to 22nd Street, 22nd Street to Jerrold Avenue, Jerrold Avenue to Donner Avenue, and Traction Power Systems. As a piling subcontractor, Mitchell is working on the MUNI Metro East Light Rail Vehicle Maintenance and Operation Facility. When completed, the light rail will provide service up and down Third Street between downtown San Francisco and points along the Bayshore Corridor.
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· 3rd Street Light Rail - 4th Street Bridge
Seismic Retrofit & Rehabilitation of the 4th Street Bridge, San Francisco, CA. The bridge work consists, in general, of earthquake retrofitting and rehabilitation the historic Fourth Street Bridge in San Francisco, originally built in 1916 by Mr. Strauss (who designed and built the famous Golden Gate Bridge). Work includes replacing the reinforced concrete "T" girder approach structures with reinforced concrete slab superstructures supported on new 36" CISS driven steel piles; constructing a temporary cofferdam, excavate and dispose of hazardous and non-hazardous waste and demolish the existing concrete bridge foundations above and underwater; constructing a reinforced concrete submerged pit structure supported on 36 " CISS driven steel piles within the cofferdam; removing the existing above ground counterweight and replacing it with a GFRP simulated counterweight. Project also includes retrofitting and rehabilitating the existing Operator House and Watchman House. Constructing light rail trackwork and the associated trolley arch overhead catenary system and traction electrification system is also included in the project work.
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· 3rd Street Light Rail - King Street to 22nd Street
Construction of 1.8 miles of mass transit light rail through San Francisco from 4th Street to King Street to 3rd Street and 22nd Street. Project involves relocation of existing utilities including sewer main (ranging from 6" to 48" in diameter), ductile iron water main (ranging from 6" to 16"), auxiliary water supply system, and electrical ductbank; installation of 1.8 miles of Ri60 girder rail and associated special trackwork; roadway re-alignment and reconstruction; construction of nine boarding platforms; architectural track pavement; flatwork and landscaping; overhead catenary and traction power system; and traffic signalization.
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· 3rd Street Light Rail - 22nd St. to Jerrold Ave.
This project not only consists of the installation of 2.2 kilometers of double track but also includes a complex utility upgrade system incorporating the coordination and installation of numerous integrated utilities along the Third Street corridor.
This project involves the installation of approximately 7650’ of MUNI underground ductbank communication systems to power the light rail, electrical traction power lines, raceways, lighting systems and rail signalization systems. Installation of overhead electrical contact power systems are included in this work also.
Full upgrades of 7796’ of San Francisco Water Department potable water lines, and 2600’ of Fire Department Auxillary Water Supply Systems lines are a major component of the project.
Approximately 8320’ of gravity fed sewer line is also installed during this project.
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· 3rd Street Light Rail - Jerrold Ave to Donner Ave
This project is being built for San Francisco Municipal Railway and is located in San Francisco, CA. The project scope is construction of new light rail; includes construction of underground utilities for electrical, sewer, water and high pressure water systems; track work, transit platforms, sub-sidewalk basement modifications, roadway pavement, landscaping, street lighting, traffic signals, and overhead catenary system. The new sewer line (10" to 27" diameter pipe) equals 2,539 lineal meters or 8,330 lineal feet.
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· Traction Power Systems, San Francisco, CA
The Traction Power System project consists of constructing two concrete masonry block substation buildings with steel trusses and corrugated metal deck, plumbing and drainage services to accommodate the Traction Power Equipment; i.e. DC switch gear, AC switch gear, transformer and rectifier, fire suppression system and air distribution equipment, power SCADA equipment, new MIMIC panel board and CCTV system. Some of the building finishes are brick veneer, plaster, roll up door and preformed metal roofing. Part of this contract also included the construction of ductbank from each building to Third Street to provide power to the Third Street Light Rail Project.
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· MUNI Metro East Lt. Rail Vehicle Maint. - Piling
The MUNI East Light Rail Vehicle Maintenance and Operation Facility is a Pile Driving Project for Mitchell Engineering. The project consists of constructing a new facility for the storage, maintenance, and operation of MUNI's new light rail vehicles. The facility totals 13 acres and will offer and initial storage capacity of about 80 light rail vehicles.
As a subcontractor to McCarthy Building Companies, Mitchell’s responsibility is driving 879 14” concrete precast piles. This will serve as foundation work for the maintenance yard.
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· Raw Water Facilites, Oakdale, CA
The Raw Water Facilites Project is the initial constructed element that feeds water to the South County Water Treatment Plant. The project extends through several endangered species habitats. The work includes a fish screened intake manifold cleaned by an air backflush system. The manifold consists of three screens each capable of passing 22 mgd, and has an allowance of space for two additional screens. The intake manifold feeds a 72" diameter mortar coated and lined steel pipeline that allows 44 mgd of glow to the water treatment plant. The 72" line is buried in the reservoir bottom and extends approximately one mile to an encased penetration of the earth filled dam. From there the 72" line extends another two miles to the water treatment plant. The last two miles of line is buried in Dobbs Road, a major Stanislaus County Road and feeder to recreation at the Woodward Reservoir. Other features of the project include the water quality wall. The purpose of the wall is to contain "body contact" water from the intake, allowing the majority of the reservoir surface to be used for recreational purposes. A low water by pass of 66" diameter mortar coated and lined steel pipe is attached to the existing reservoir powerhouse, extends 2000' to join the 72" line after it leaves the dam penetration. Installation of a new 108" hydraulic controlled sluice gate controls an alternate distribution of water from the powerhouse to the water treatment plant.
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· Wet Weather Program - Phase 1
The Wet Weather Program project is located in South San Francisco and primarily consists 9 areas of work. The work includes "Upgrade to San Mateo Pump Station"; "Construction of New Shaw Road Pump Station"; Construction of "New 36-inch Lowrie Force Main"; "Construction of New 42 inch Shaw Road Force Main"; "Construction of New Effluent Storage Pond and Pump Station"; "Construction of New Vactor Unloading Station"; "Installation of New Influent Pumps"; "Installation of New Effluent Pumps" and the Final Area of work is "Construction of New Gravity Sewer Mains".
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· Central Pump Station Improvements
The retrofit/upgrade to Central Pump Station located in San Francisco on Sloat Boulevard between 22nd and 23rd Avenues. Central Pump Station provides drinking water to the city’s residents. Work consists of replacing aging pumps, electrical controls, switches and other mechanical equipment on the station, as well as structural work to improve the station’s appearance and protect it from earthquakes and other daily use. Project duration is 18 months, beginning in May 2004. This project has a cost of close to $9 Million.
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· Summit Reservoir
Our Summit Reservoir project entails the seismic retrofit and other improvements to the two basins at Summit Reservoir in San Francisco. The scope of work consists of replacement of the existing structure to meet seismic and health codes and a new security system for the reservoir entrances and valve house. Civil work includes finishing and installing a new 16-inch diameter ductile iron inlet pipe connection from the existing water main at La Avanzada Avenue and Palo Alto Avenue into both basins of the reservoir. Other structural work consists of constructing drilled piers and pier caps, perimeter and shear walls and foundations, a new reinforced concrete lining overlay over the existing concrete lining on the floor of the reservoir, two new reservoir entrance structures, and the inlet valve vault. Improvements to the valve house include the installation of valves, piping, and flowmeters inside the new inlet valve vault, and replacing the two existing outlet valves.
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· O'Shaughnessy Camp Domestic Water Sys. Improvement
O’Shaughnessy Camp Domestic Water System Improvements project involves mechanical and electrical work at O’Shaughnessy Dam and the Compound and Roadway, located at the Hetch Hetchy Reservoir. Mechanical work at the Dam consisted of removing and disposing of the existing water piping from the flange connection, in ladder wells, stair wells, and other locations, and the installation of schedule 10 seamless Type 304/304L stainless steel grooved end and other piping for domestic water piping. Mechanical work at the Compound and Roadway consisted of removing and disposing of all existing domestic water and sewage piping, valves, hydrants, water meters, drinking fountains, valve boxes, and concrete and wooden supports. Domestic water piping was also installed. Electrical work at the Dam and Compound consisted of furnishing and installing a 3” conduit, including all conduit hangers and supports, from the dam to the Water Quality Building, continuing to the existing water tanks.
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· 48" Lincoln Way Pipeline From Sunset Reservoir
The project consists of furnishing and installing approximately 13,000 linear feet of the 48”, 42”, 36” and 30” diameter welded steel pipe from Sunset Reservoir to Lincoln Way and 6th Avenue. Other work includes constructing a concrete vault, flow meter, butterfly valves, air valve, blow-offs and 8” bypasses. In addition, there will be traffic routing work, traffic control, demolition and restoration of street pavement and sidewalks, relocation of underground utilities, and roadway restoration work.
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· Red Mountain Bar Bypass Valve and Generator Bldg.
This project consisted of constructing and installing a Valve Bypass and Generator Building at Red Mountain, located on Lake Don Pedro in Tuolomne County, CA.
Civil work included fitting and sealing a 30” and 36” pipe adaptor to an existing 12” thick reinforced wall, installing two concrete thrust blocks to repair concrete footing, installing a propane tank and a 7-foot tall security fence and access gate. Mechanical work included installation of 30” and 36” pipe and valves, the installation of a propane-fueled electrical generator, installation of a propane tank, and sluice gate repairs and upgrades.
Electrical work included the installation of electrical cabines, RTU cabines, conduits, lighting and wiring inside the building.
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· Skywest Pump Station
Working with the City of Hayward, the SF Public Utilities Commission, and EBMUD, this project involves upgrades to the Skywest Booster Pump Station in Hayward. Work includes constructing the new Skywest Pump Station Building, replacement of four 33" isolation valves and two 42" isolation valves on the Hesperian Aqueduct, and installation of intertie pipeline and 36" pipes inside and outside the new pump station. Other upgrades include four 500 hp horizontal split case pumps, 1,500 kW standby generator with fuel storage tank, new transformer, switchgear, valves and piping, 7,205 feet of 36" transmission pipeline, and an additional 273 feet of pipe to be installed inside a new casing.
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· Sly Creek Tunnel Upgrade
This project consisted of protecting the tunnel from damage by falling rocks. The back and sides of the tunnel were scaled down of all loose rock. Two dozen #8 Williams bolts were installed. The bolts that already existed in the tunnel have weight on them. They were left alone but reinforced with the new bolts. Mitchell also added wire mesh to support the old rock bolts and protect the soft seam running across the top of the tunnel.
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· Bradshaw Interceptor Section 6B
Located in Sacramento, the Bradshaw Interceptor Section 6B/Bradshaw Road Improvement Project consists of installing approximately 8,662 linear feet of 108 inch diameter interceptor, 493 linear feet of 90 inch diameter interceptor, 2,631 linear feed of 84 inch diameter interceptor, two concrete structures, 18 manholes, 3 flowmeters and appurtenances. Approximately 384 linear feet of 108 inch pipe will be installed by tunneling and 8,278 linear feet will be installed in open-cut excavations. Bradshaw Road improvements between Florin Road and Jackson Road include clearing and grubbing, tree removal, 14,000 cubic yards of roadway excavation, grading, pavement planning and removal.
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· Arden Parallel Force Main
This project entails the construction of a force main pipeline generally along the American river from Approximately 1,000 feet northwest Northrop near the Arden Pumping Station to a point near the Fairbairn Water treatment Plant. The project includes approximately 10,400 feet of 60" diameter pipe, two connection vault structures, two jacking and one receiving shaft vaults, three hot-taps of 60-inch force main and 26-inc bypass piping at two locations, four access manways, two air release/vacuum valve vaults, two open cut crossings of the American River Levee, two 60-inch tunneled crossing of the American River, and three augured access shafts for tunneling.
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· San Jose Diridon Station
The project is located in San Jose, CA. This project is to reconstruct and the upgrade of existing platforms and handicap accessible ramps for passengers and track improvements. Diridon Station is a historic landmark as well as a very important present day passenger loading and unloading facility that accommodates at least 68 trains a day, during the work week.
Mitchell’s schedule is to make improvements primarily on the weekends when the commuter trains are not running. The project will consist of about 2000 feet of rebuilt passenger loading platforms, lengthening of ramps leading from the passenger tunnel to the platforms to improving the handicap access. Installation of a elevator in the station will also make the access better for handicapped people. In addition, there is more that 5,000 feet of track that will be replaced, repaired or realigned in the station area.
New construction will be in keeping with the historical style so that improvements will blend into the architecture. The overall project is around $4,500,000. The project was completed ahead of schedule and was able to receive the first run of the famous CalTrain "Baby Bullet" which made its debut the first week of June 2004.
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· Paseo Padre Parkway SFPUC Supply Pipeline
This project consists of furnishing and installing approximately 965 linear feet of 24" diameter welded steel cement lined and dielectrically coated pipe and appurtenances, fabricating and installing of approximately 94 linear feet of 36" steel casing under UPRR tracks, fabricating and installing approximately 175 linear feet of 36" steel casing. In addition, the project involves making final closures to the existing district and SFPUC water mains, and surface restoration.
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· Colgate Penstock Shutoff Valve Project
This project will protect the Colgate Powerhouse and unlined portion of the 6 mile long penstock from secondary damage caused by an uncontrolled rupture flow. The project includes the demolition and removal of a portion of the existing 165-inch penstock; the modification of the existing reinforced concrete foundation; the supply and installation of the 165-inch penstock shut-off butterfly valve and associated spool pipework; and supply and install of the operating and control equipment. On-site construction works take place from April 2006 through to February 2007.
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· Narrows II Powerhouse Flow Bypass System
This project requires that a flow bypass system be constructed for the purpose of allowing the continuance of flow in the Yuba River while the Narrows II Powerhouse is shut-down for maintenance works. Work includes the drill & blast excavation of the bypass tunnel, bypass structure and discharge channel; supply and installation of 114-inch steel tunnel liner and 90-degree tee connection to the existing penstock; construction of the reinforced concrete bypass valve structure and minor powerhouse structural modifications; the supply and installation of the 78-inch fixed cone bypass valve, 78-inch knife gate guard valve, and the 168-inch turbine shutoff butterfly valve; including operating and control equipment. On-site construction works take place from January 2006 through to February 2007.
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· S-8 Sewer Junction Sewer Replacement
The project consists of the replacement of the S-8 Sewer Junction Structure with a new structure and includes all appurtenant hardware for the City of Pleasanton. Work includes sewer bypass pumping of existing sewer effluent, demolition of the existing junction structure, installation of a prefabricated diversion structure, flap gate and access gate, two 21" by 21" sluice gates and one 30" by 30" sluice gate.
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· Redwood City Recycled Water Project – Phase 1
The project consists of constructing a water distribution system. Work includes 2,290 feet of 30” recycled water pipeline along Radio road and Redwood Shores Parkway, 40 feet of 24” recycled water pipeline along Redwood Shores Parkway, 2,330 feet of 20” water pipeline along Radio Road and Redwood Shores Parkway, 5,790 feet of 14” recycled water pipeline along Marine Parkway and Island Parkway, and 250 feet of 8” recycled water pipeline along Bridge Parkway and Shell Parkway.
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