Leighton - Projects

Leighton conducted a Phase II ESA that included a geophysical survey at a former custom trailer manufacturing site, which has since been demolished. Prior to this last land use, the now vacant, 5-acre site was formerly an auto dealership and is bounded by Interstate-215, vacant land, and occupied and abandoned industrial buildings.

Thirteen hydraulic hoists were identified on site, as well as stained soil, concrete, and asphalt. With results from the geophysical survey, Leighton discovered an undocumented drywell with subsurface contaminationm and contamination was identified surrounding some of the hydraulic hoists and sumps. Based on the results of our investigation, a cost estimate for remediation was prepared, as well as a health and safety plan. The owner-agency is currently using our report, cost estimate, and scope for remediation to apply for a brownfields grant that will assist in the future redevelopment of the subject site.

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Project Name: Penske Truck Leasing Facility
Location: Sun Valley
Services: Environmental, Geotechnical, Testing
Market Segment: Commercial / Industrial / Retail

Project Description:

Resulting from a successful reclamation of an abondoned gravel pit is the new Penske Truck Leasing Facility, in which Leighton was the Geotechnical Engineer of Record. Leighton's scope of work included a Phase I ESA for the refinancing of the project; geotechnical exploration and design of reclamation; a methane survey for the design of a methane mitigation system in accordance with City of Los Angeles requirements; and soils and materials testing during remedial earthwork, pile driving of pre-cast, pre-stressed concrete piles, and construction of the leasing and maintenance facility.

Originally, the gravel pit was backfilled with up to 90 feet of hydraulically sluiced silts and clays, the waste by-products from sand and gravel production at and near the site. Subject to compression, Leighton designed and implemented innovative mitigation methods to reduce total and differential settlements. Leighton's solutions incorporated the design of hinged-approach slabs-on-grade, buried utility "galleries", and geogrid-reinforced pavement subgrades. These solutions now support the office/maintenance building, diesel fuel tank, fuel island, tractors and semi-trailers.

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Project Name: Promenade In Temecula Expansion Project
Location: Temecula
Services: Geotechnical, Testing, Inspection
Market Segment: Commercial / Industrial / Retail

Project Description:

The Promenade in Temecula is the largest mall in south Riverside County and is currently undergoing an expansion and improvement project. Leighton is presently on this project providing materials testing and inspection services.

The mall currently includes Sears, JC Penney, and Macy’s as anchor stores, and a 14-screen, 60,000-square-foot Edwards Cinema. By 2009, the mall will include a new wing, a 3-story parking structure to the east of Macy’s, and a 5-story parking structure east of Edwards Cinema.

During the design phase, Leighton performed geotechnical and geologic investigations, and percolation studies to evaluate subsurface conditions. We addressed to the client the concern of the settlement and liquefaction hazard zone that the mall is situated on and presented recommendations for seismic design parameters, foundation and pavement design and earthwork parameters. In addition, Leighton was on site performing observation and testing during grading activities.

When plans first emerged to develop this mall in 1997, Leighton engineers collaborated with structural engineers for each major building to resolve the issues associated with differential settlement. Considering such issues, as well as the rigid bearing capacity needed, Leighton offered complex foundation systems and brought results with variable foundation designs. Additionally, Leighton was on site for geotechnical observation and soils testing services during original grading and construction of the mall.

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Project Name: Renee and Henry Segerstrom Concert Hall
Location: Costa Mesa
Services: Geotechnical
Market Segment: Commercial / Industrial / Retail

Project Description:

Leighton provided a geotechnical and seismic investigation for the design of this 260,000-square-foot performing arts complex. Valued at $260 million, this concert hall surrounds an elegant atrium with its stone-facade exterior and glass curtain wall. Within its glass walls are artist accommodations, rehearsal spaces, theatre operations, a private donor room and a public restaurant.

In support of the structural design elements, site-specific response spectra and lateral ground displacements were provided as well as analysis and design for shoring and pile foundation. Leighton's shoring alternatives resulted in a savings of $2 million in excavation and basement wall construction costs. The results of the indicator pile program reduced the pile length by more than 10 percent and shortened the original pile driving schedule by more than a month.

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Project Name: RiverView at Santee
Location: Santee
Services: Geotechnical Consultation, Observation and Testing
Market Segment: Commercial / Industrial / Retail

Project Description:

The new RiverView at Santee is a 108-acre, master-planned business park highlighted by the 63,500-square-foot RiverView Professional Center. Its six-, one- and two-story, Class A office/medical buildings are environmentally friendly and LEED certified. The remainder of the business park is slated to have additional corporate headquarter offices, Research & Development buildings, retail and condo real estate, and a multiplex movie theater.

Leighton was selected by developer Ryan Companies to provide geotechnical engineering consulting services for the design and construction phases of this project. Leighton's geotechnical investigation consisted of a subsurface exploration which involved excavation, logging and sampling of four exploratory borings. With laboratory test results and analysis completed, recommendations for foundation design and grading parameters were provided. Geotechnical observation and testing services were provided during remedial grading of the project site as well.

In addition, Leighton provided geotechnical consultation for the installation of three sewer pipelines: an 18-inch- and 36-inch-diameter pipeline, and an emergency replacement of a damaged 27-inch sewer pipeline with a 30-inch, 900-foot-long sewer main. Our consultation included recommendations for the excavation and stabilization of the sewer trenches required for this portion of the project.

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Project Name: Market Street Village
Location: San Diego
Services: Environmental
Market Segment: Community Development

Project Description:

Located in the trendy East Village of downtown San Diego is Market Street Village – a 6-story complex with 225 apartments atop a 43,000-square-foot Albertson’s supermarket along with subterranean parking. For construction of this mixed-use development, removal of known lead-impacted artificial fill soils had to be completed first.

Leighton provided the oversight during the remedial excavation of 14,600 tons of lead-impacted soil, one abandoned cistern and several burn ash pits from the site. The remedial excavation was conducted in accordance with a site specific Property Mitigation Plan (PMP), which was reviewed and approved by the SD-DEH. Confirmation samples were collected to confirm the effective removal of impacted soil to a site cleanup level established in the PMP. Based on the excavation and results of analytical testing, Leighton issued a closure report to the SD-DEH and attained approval for the construction of Market Street Village.

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Project Name: The Treo at Kettner
Location: San Diego
Services: Geotechnical, Testing
Market Segment: Community Development

Project Description:

Located within walking distance to the harbor, shopping and work, this 24-story condominium development consists of 480,000 square feet of mid-rise and low-rise units on a 60,000-square-foot block in Little Italy.

Leighton performed geotechnical services during the rough- and fine-grading operations and shoring installation including soil nails, soldier beams, lagging, and tie-backs, field and laboratory test results, results of soils nail and tie-back proof tests, and the geotechnical conditions encountered during the rough- and fine-grading operations at the site. Our report also presented geotechnical recommendations for the development of the site.

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Project Name: The Villages of Columbus at Tustin Legacy
Location: Tustin and Irvine
Services: Environmental, Geotechnical
Market Segment: Community Development

Project Description:

The Villages of Columbus is one of the first residential communities to open at Tustin Legacy, formerly Tustin Marine Corps Air Station (MCAS), and also known as the ultimate infill project of Orange County. The Villages of Columbus encompasses two neighborhoods - Columbus Grove and Columbus Square – with a total of 1,542 homes. These homes occupy three parcels of land that total approximately 150 acres.

Leighton simultaneously provided independent preliminary geotechnical investigations for three parcels of land prior to construction of The Villages of Columbus. With the results and analyses from our geotechnical investigations, we were able to provide our client the needed site-specific subsurface conditions, potential geotechnical issues, such as liquefaction, shallow groundwater, and expansive soils, along with grading options. Our recommendations were refined through the grading plan review and rough grading. Rough grading was performed under the observation of Leighton’s geotechnical personnel. The development of The Villages of Columbus straddles the cities of Irvine and Tustin, which required close coordination for approvals.

Prior to the geotechnical investigation, Leighton conducted Phase I ESAs in each of the three areas. Each area had unique characteristics and considerations including multiplex residential dwellings, vacant land, non-residential buildings, and blimp mooring pads.

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Project Name: Trio Apartments
Location: Los Angeles
Services: Geotechnical, Testing, Inspection
Market Segment: Community Development

Project Description:

It was the city's first parking garage, along with neighboring retail buildings, that were demolished for use of redevelopment for the new Trio Apartments - the first mixed-used development to be constructed in Pasadena's historic Playhouse District. This $70-million project includes three, 4-story apartment buildings with two levels of subterranean parking, and a fourth apartment building at five stories, with 14,600 square feet of street-level retail and 3 levels of subterranean parking.

Leighton conducted the feasibility study for the project and, subsequently, the subsurface investigation to support building designs for foundations and other structural components. Because the site is located in a seismically-active region, Leighton performed a Probabilistic Seismic Hazard Analysis (PHSA) to evaluate the likelihood of various ground motion levels at the site, or Peak Horizontal Ground Acceleration (PHGA). This approach took into account historical seismicity, geological slip rate of all active faults within 62.5 miles of the site, and site-specific response characteristics.

During the fast-paced construction phase of the Trio, Leighton was on site providing geotechnical observation for shoring, mass excavation, grading, backfill, and asphalt placement. Also, materials testing and inspection and deputy inspection were provided for 30,000 cubic yards of concrete, 11 million pounds of reinforcing steel, 16 miles of post-tension cable and 100,000 square feet of masonry.

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Project Name: Hertzberg-Davis Forensic Science Center, CSULA
Location: Los Angeles
Services: Geotechnical, Testing
Market Segment: Institutions and Universities

Project Description:

The new Hertzberg-Davis Forensic Science Center, located on the Cal State LA campus, is a 5-story crime lab being shared jointly by the University's School of Criminal Justice and Criminalistics department, Los Angeles Police Department, Los Angeles County Sheriff's Department, and the State Department of Justice Bureau of Forensic Services. With construction cost at approximately $102 million, this 209,000-square-foot science center is the largest forensics facility in the nation. It houses lecture and meeting halls, and university labs for studying forensics or DNA analysis, biology, chemistry, toxicology, and drug analysis.

Leighton performed the feasibility study and geotechnical investigation for the design and construction of the new science center. During construction, Leighton was on site to perform daily geotechnical observation and testing of earthwork such as grading activities, and excavation and back-fill of utility trenches and deep foundation locations.

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Project Name: Kaiser Permanente Ontario Vineyard Medical Center
Location: Ontario
Services: Geotechnical
Market Segment: Institutions and Universities

Project Description:

Located on a 28-acre master-planned campus, the new Ontario Vineyard Medical Center is part of Kaiser Permanente’s $2-billion expansion plan in the Inland Empire. Leighton is providing geotechnical engineering consultation for this two-phase construction process, with the first phase already complete with three new buildings - a surgical center, call center, and a 4-story medical office building with a basement-level radiation therapy center.

The medical office building, an unbonded-braced structural steel frame, was built to OSHPD 3 standards to mitigate both strong earthquake lateral loading and anticipated settlement issues. Supporting the structural engineer, Leighton performed geotechnical analyses of seven sets of earthquake histories in conformance with California Building Code. Using spectral matching analysis, Leighton’s results presented 14 sets of time histories deriving from the seven earthquakes. With potential strong seismic shaking, compressible and collapsible fill and alluvial soils, and the loose and dry nature of the on-site sand as major concerns, and after extensive evaluation of alternatives, Leighton’s recommendation to the design team to utilize a mat foundation to support the medical office building was approved by OSHPD.

The second phase of the Ontario Vineyard Medical Center is currently under construction and will consist of seven additional structures:

a 6-story hospital, and 6-story medical office building
a 2-story administration building
Three parking structures (5, 6, and 8 stories)
New central plant and IT building

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Project Name: San Bernardino Valley College
Location: San Bernardino
Services: Geotechnical, Testing, Inspection
Market Segment: Institutions and Universities

Project Description:

The discovery of the San Jacinto fault running under San Bernardino Valley College called for a master plan to replace five campus buildings. From the design stage to the construction phase, Leighton was provided geotechnical, and materials testing and special inspection services for the new five campus buildings:

Administration/Student Services – 33,000 square feet
Learning Resource Center – 40,000 square feet
Campus Center – 35,000 square feet
Life Science – 43,000 square feet
Arts Building – 22,000 square feet

Associated with this project included new utilities, landscaping, parking lots, and portions of campus access roads. Leighton provided field technicians for soils and materials testing and DSA-approved special inspectors during grading and construction of the five new buildings. Soils and materials testing were completed in our DSA-certified laboratory, as required by the soils report, the construction manager representing the District, the architect, and the resident DSA inspector.

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Project Name: Santa Barbara Cottage Hospital
Location: Santa Barbara
Services: Peer Review of Environmental Impact Report
Market Segment: Institutions and Universities

Project Description:

To comply with the State Senate Bill 1953, which mandates that acute care facilities be brought up to current seismic standards, the Santa Barbara Cottage Hospital is currently under construction for a modernization and seismic upgrade. Structures have been demolished to provide for a new 337-bed, state-of-the-art teaching hospital and trauma center; construction of three nursing pavilions with diagnostic and therapeutic wing; a new child care center; new separate employee and patient parking structures; new storm drain culvert and associated water and sewer line improvements; new underground utilities and energy; and 7 intersection improvements. The redevelopment of this hospital is estimated to cost up to $550 million and be completed by 2012.

Well before construction and as part of the Environmental Impact Report, Leighton provided peer review of the geologic and geotechnical reports which provided preliminary assessment of the potential geologic, geotechnical, and seismic conditions that may impact the design and construction of the redevelopment of the hospital. The geotechnical assessment included:

Earth units on site and their engineering characteristics
Geologic structure
Faults and seismicity
Secondary seismic hazards
Existing landslides
Stability of proposed slopes
Groundwater conditions
Subsidence
Mineral resources

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Project Name: Bobby G. Duke Middle School
Location: Coachella
Services: Environmental, Geotechnical, Testing, Inspection
Market Segment: K-12 Schools

Project Description:

At a cost of $34 million, the 1950s era elementary school underwent a makeover with the remodeling of 27 classrooms and the addition of 20 new ones transforming the school into the modern, Spanish mission-style, Bobby G. Duke Middle School. The 85,000-square-foot campus now features five new buildings including an administration building, multi-purpose room, and a state-of-the-art kitchen.

Leighton was contracted by the Coachella Valley Unified School District to perform a Preliminary Endangerment Assessment for the expansion and conversion project of the school. Our professional services were then extended through the design and construction stages with a Phase I ESA, geologic hazard review, geotechnical investigation, preliminary percolation testing, and materials testing and special inspection.

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Project Name: Hawthorn Elementary School Relocation
Location: Riverside
Services: Environmental
Market Segment: K-12 Schools

Project Description:

Students of Hawthorn Elementary School are now enjoying a new 55,980 square foot facility in Riverside's historical district. The new campus replaced the original Hawthorn Elementary School site as it was seriously impacted and deemed unsafe due to its close proximity to a major freeway, railway and electrical substation encroachment, and increased traffic volume. The new Hawthorn Elementary School occupies 10 acres and includes 34 classrooms, a library, multipurpose room, lunch shelter, and playfields.

When the new site was selected, Leighton was called upon for professional environmental services. Leighton performed an Environmental Hazard Assessment, Geological Hazard Survey, a Phase I ESA and Limited Phase II Soil Investigation at the school site. The Phase I identified the site as a former citrus grove and the subsequent Phase II Soils Investigation was performed as a preliminary assessment for metals and pesticides. We evaluated surface soils for PCBs below power poles and wind turbine, and one sample of elevated lead concentrations was identified. The site was further assessed under a Preliminary Endangerment Assessment (PEA) for pesticides relative to former agricultural use by sampling in the area of the elevated lead concentrations. The results of the PEA indicated that the human health risk assessment was acceptable for unlimited land use and the lead concentration identified from the Phase II was of limited extent and de minimus quantity. A "No Further Action" recommendation was made to the DTSC in the Draft PEA submittal.

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Project Name: Panorama High School
Location: Panorama City
Services: Geotechnical, Testing
Market Segment: K-12 Schools

Project Description:

Serving a dense urban area, Panorama High School is located on 18.22 acres – about half the size as a traditional high school in California. The $71.8 million high school designed to accommodate 2,100 students features three 4-story classroom buildings, an auditorium; a food service/physical education complex that houses two gyms and an outdoor Olympic-size pool; and basketball, volleyball and tennis courts on the deck of the on-grade parking structure. More than 10 acres of land is occupied by a full stadium and other athletic fields.

Leighton completed a geotechnical investigation and geologic hazard evaluation to provide design parameters for the construction of the high school along with observation and testing during earthwork, installation of the temporary shoring during excavation, and construction of foundations.

The major geotechnical challenge for this project was the potential for dynamic settlement of native loose soils that could occur during an earthquake. To minimize the effects of potential dynamic settlements and to provide uniform support to the buildings on a shallow foundation, Leighton recommended the buildings be supported on a 10-foot engineered fill blanket. Other geotechnical engineering recommendations also included the design of excavation stability and temporary shoring, site earthwork, spread footings, foundations, retaining walls, slabs-on-grade, and asphalt and pavements.

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Project Name: Environmental Support to Unocal
Location: Southern California
Services: Environmental
Market Segment: Oil / Refinery

Project Description:

During the course of our 20-year relationship with Unocal Corporation, we have provided a wide range of environmental services on more than 200 sites throughout southern California. Many of these sites were taken from initial assessment through complete remediation and Site Closure, and then sold for redevelopment by various city/county agencies or private developers. Sites have included operating and non-operating service stations and bulk fuel storage facilities, vacant properties, pipeline easements, and pesticide mixing facilities.

Our services have included:
• Phase I ESA
• Phase II site characterizations
• Installation of hundreds of groundwater monitoring wells
• Feasibility design
• Construction of remediation systems

Along with remediation services were many remedial excavation projects from 50 to over 10,000 cubic yards of soil, completion of health risk assessments, traffic management plans, feasibility studies and remedial action plans.

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Project Name: Site Assessment & Remedial Design for G&M Oil
Location: Southern California
Services: Environmental
Market Segment: Oil / Refinery

Project Description:

Leighton has conducted over 50 environmental site assessments for G&M Oil at properties throughout southern California since 2002. Our services have included Phase I ESAs, soils boring and groundwater monitoring well installation, periodic groundwater, feasibility studies, soil vapor extraction tests and remediation as well as dual phase extraction.

To achieve G&M's goal of regulatory closure, Leighon works closely with the local oversight agencies to ensure that the projects move forward. The majority of the G&M sites that Leighton has worked on have been accepted by the State of Califrnia UST reimbursement fund. Leighton completes the reimbursement request forms for G&M and is well versed in all aspects of the UST reimbursement fund. Projects have included:

Station 16, Whittier
Station 29, Riverside
Station 31, Claremont
Station 32, Westminster
Station 33, Huntington Beach
Station 45, San Diego
Station 49, Santa Ana
Station 50, Stanton
Station 61, Stanton
Station 63, San Diego
Station 119, San Bernardino

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Project Name: On-Call Remediation Services for Port of Long Beach
Location: Long Beach
Services: Remediation Services
Market Segment: Ports and Harbors

Project Description:

Leighton was recently selected by the Port of Long Beach (POLB) to be on an on-call contract to provide remediation services. This is Leighton’s third consecutive on-call contract with the Port. Over the last 15 years of providing environmental engineering and remediation services, we have completed over 40 work orders for various geo-environmental projects.

Work orders have included environmental audits, Phase I ESA’s, Phase II ESA's for underground storage fuel tanks (USTs) and non-UST sites, characterization of stockpiles, lead and asbestos surveys, and feasibility studies for evaluating remedial alternatives.

Our experience with the Port of Long Beach involves sampling for sources with possible contamination. Such sources have been abandoned drums, dry-docked barges and boats, and soil stockpiles. Samples were analyzed for the following types of contaminants:

Volatile organic compounds (EPA Method 8260)
Semi-volatile organic compounds by (EPA Method 8270) California Title 22 Metals
Pesticides and Polychlorinated biphenyls (EPA Methods 8080/8081)
Total petroleum hydrocarbon-carbon chain analysis (EPA Method 8015)
Lead (Soluble threshold limit concentration)

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Project Name: Pier A - Hanjin Container Terminal
Location: Long Beach
Services: Environmental, Geotechnical, Testing
Market Segment: Ports and Harbors

Project Description:

To accommodate trade expansion, the Port of Long Beach embarked on an aggressive capital improvement program costing over $2 billion for the development of the 170-acre, state-of-the-art terminal for Hanjin Shipping—nearly tripling the size of its existing 57-acre facility.

For the design and construction of the Hanjin Container Terminal, Leighton was selected to provide geotechnical, environmental, construction observation, and material testing services for berths A-88 through A-96. Field activities included on- and off-shore drilling and sampling, CPT soundings (several of which extended through the clay core of the existing levee), and laboratory testing to determine foundation soils, sumps and their geometry, seismicity and liquefaction potential, and total and differential settlement. Leighton used this data to develop design parameters for the wharf structure, rock-dike and pile designs, building foundation systems, toe-drains, an Edison substation and light poles, grade separation pavement, an intermodal rail yard facility, and transtainer and forklift areas.

Additionally, the down-drag effects of the proposed landfill on the Terminal Island Freeway were studied, and Port staff implemented our constructability analysis. Leighton made recommendations for over 600,000 cubic yards of underwater fill and a total of 2.7 million cubic yards of landfill at the site.

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Project Name: Caltrans District 7 Headquarters
Location: Los Angeles
Services: Environmental, Geotechnical, Testing
Market Segment: Public Facilities

Project Description:

A distinctive landmark located in downtown Los Angeles is the new headquarters building for the California Department of Transportation (Caltrans) District 7. Its L-shaped structure stands 14 stories tall with four levels of subterranean parking and houses an auto shop, a conference center, cafeteria, and a day care center. Providing environmental, geotechnical and testing services for this $171-million building, Leighton worked under a fast-track construction schedule to meet the deadlines of this three-year design/build project.

Along with completing an environmental assessment of a former gas station within the site property, Leighton provided the geotechnical design recommendations for the simultaneous construction process that involved excavation, shoring, foundations for basement walls and floor slabs, and earthwork.

To support the 50-foot excavation of the subterranean parking structure Leighton designed the shoring system of soldier beams and tiebacks, and provided observation and testing during installation of the 700 tiebacks. Leighton also designed the dewatering system to mitigated high groundwater level and recommended a uniform foundation that minimized construction noise and vibration. Considering the potential for differential settlement of the foundations and shallow groundwater, special seismic parameters also were incorporated into the new building’s design to comply with the latest code requirements, and since the building is classified as an essential facility, Leighton’s design parameters were compliant with Division of the State Architect regulations.

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Project Name: Temecula Public Library
Location: Temecula
Services: Geotechnical, Testing, Inspection
Market Segment: Public Facilities

Project Description:

Leighton field technicians and geologist were onsite on a full-time or as-needed basis during the rough grading operations for the Temecula Public Library. Grading of this steep hillside property required careful geologic observation to confirm a stable hillside was prepared in order to receive the foundation supporting fill soils. Nearly continuous observation and testing was performed to assure compliance for compacted fill soils and site grading. Geotechnical observations and testing services were performed as well as geotechnical recommendation during the course of grading. Leighton performed field density and moisture content testing using the nuclear gauge method (ASTM Test Methods D2922 and D3017). Leighton's staff provided consultation and field recommendations to meet contract schedule and earthwork construction completion.

For materials testing, Leighton provided reinforced concrete placement inspection during the placement of caissons, grade beams, spread footings, slab-on-grade, slab-on-deck and curb and gutter. We observed and supervised the placement of epoxied dowels and provided continuous inspection for concrete masonry unit construction. Our inspectors provided structural steel shop fabrication and field welding and high strength bolting inspection throughout the duration of the construction process.

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Project Name: Cantu-Galleano Ranch Road at I-15 Interchange
Location: Mira Loma
Services: Environmental, Geotechnical, Testing
Market Segment: Transportation

Project Description:

More than 20 years of planning, design and discussion came to fruition last year when the $47 mil Cantu-Galleano interchange opened to relive traffic on the I-15 and surrounding roads. A heavy industrialized area, the interchange pulls the heavy truck traffic off the roads by providing an access route to the I-15. The new interchange includes on- and off-ramps, auxiliary lanes to the Highway 60 transition and an extension of Cantu-Galleano Ranch Road from Hamner Avenue, over the freeway and east to Etiwanda Avenue

Serving in a subconsultant role, Leighton provided geotechnical observation and materials testing during the construction. Leighton provided concrete inspection during the massive concrete pour of 2200 cubic meters of concrete for the bridge deck. Working long hours, our Caltrans-certified concrete technicians prepared concrete cylinders and tested for unit weight and compressive strength in accordance with project specifications.

Leighton also performed an Initial Site Assessment prior to construction. This task involved a site reconnaissance of the right-of-way to identify areas of potential environmental concern.

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Project Name: Metro Gold Line Foothill Extension EIR
Location: Pasadena to Montclair
Services: Environmental, Geotechnical
Market Segment: Transportation

Project Description:

The planned 24-mile extension of the Metro Gold Line Light Rail Transit (LRT) will extend through 13 adjoining cities from Pasadena in Los Angeles County to Montclair in San Bernardino County. Proposed structures include 12 stations, parking structures and lots, and a 33-acre maintenance facility. The alignment crosses major washes and a river, requiring improvements to existing grade crossings and construction of new bridges.

Leighton evaluated the potential geotechnical impacts and hazards for the geologic and seismic section of the environmental impact report for the proposed extension. Our geotechnical study specifically focused a corridor study of 1,000 feet in width along either side of the proposed rail alignment. The study revealed 16 active and potentially active fault systems with significant concern for major ground shaking along the alignment, as well as liquefaction, seismically-induced inundation and ground rupture. In addition, Leighton examined the four alternatives of the proposed alignment, and evaluated the geotechnical impacts and hazards, and provided design solutions for each alternative. Leighton’s evaluation also reported on regional geology, regional faulting and seismicity, volcanic hazards, existing slope stability, and groundwater conditions for each city along the alignment.

Subsequently, Leighton was called on to provide additional services for the preliminary engineering phase of the project as part of the 30 percent design submittal. Some parts of our geotechnical investigation have been completed; however, the project is currently on hold indefinitely.

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Project Name: South Bay Expressway (State Route 125)
Location: San Diego
Services: Geotechnical
Market Segment: Transportation

Project Description:

The $635-million link to the Otay Mesa border crossing consists of two separate projects – the Gap and Connector, and the Toll Road. Leighton was retained by the SR-125 Construction Management (CM) Team to provide audit-level materials testing, project management and engineering geology services for the 9.3-mile Toll Road, which includes seven undercrossing and three overcrossing bridges, and the Otay River Bridge. As the project progressed, our role was expanded to include a variety of additional services including:

• Review of Geotechnical Design and Foundation Reports
• Geotechnical consulting
• Testing and analyses of additional materials
• Special inspection
• Phase I Environmental Site Assessment for parcel acquisition

Of major concern were the on-site geotechnical issues of slide-prone geology. Leighton’s staff of professionals identified and resolved the local geotechnical issues gaining approval of the Otay River Bridge Foundations Report. Leighton has provided consistent and timely testing and reporting in support of the Resident Engineer and CM Team throughout this design-build project. With the recent grand opening, the Expressway now provides fast and convenient access to and from Mexico and communities across San Diego County.

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Project Name: Award-winning Moonlight Beach Sewer Pump Station Expansion
Location: Encinitas
Services: Environmental, Geotechnical
Market Segment: Water Storage

Project Description:

Leighton performed a geotechnical investigation for the new above-ground pump station building over the existing pump station basin and a new subsurface emergency storage basin – a $3.7-million project. The project site is located immediately north of the Cottonwood Creek, an environmentally sensitive area, which ultimately drains westward to the surf zone at Moonlight Beach.

The primary concern of the project was that locating the proposed emergency storage basin approximately 25 to 27 feet below the existing ground surface would require dewatering. The discharge water could be impacted as identified by the California Regional Water Quality Control Board (RWQCB) San Diego Region, Order Number 2001-96. Therefore, as part of our geotechnical investigation, we performed an environmental assessment of the groundwater by installing a temporary groundwater monitoring well as part of subsurface exploration.

Analytical results, which were incorporated into the Plans and Specification, indicated that groundwater needed to be treated (four metals, chlorine, dissolved oxygen, settleable solids, total suspended solids and total coliform) prior to discharging into Cottonwood Creek. This combined geotechnical/environment characterization of the site eliminated the risk of a potentially costly change-order and delays during construction. Construction included associated piping, retaining wall, and asphalt concrete paving.

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Project Name: Sky Ranch Pump Station and Reservoir
Location: Santee
Services: Geotechnical, Testing
Market Segment: Water Storage

Project Description:

Supporting four brand-new hilltop neighborhood communities known as Sky Ranch, in the city of Santee, will be a new pump station and reservoir. The proposed 1-million-gallon concrete water tank will have an inner and outer reservoir, each being 38 feet in diameter.

Leighton performed a geotechnical investigation to evaluate the geotechnical conditions of the site and provided recommendations for the design and construction of the pump station and reservoir. Our scope of work included a subsurface exploration in which we obtained soils samples and tested for corrosion, soluble sulfate, pH, resistivity and chloride. In addition, Leighton conducted a seismic refraction study, and geotechnical analyses including a faulting/seismic analysis. Construction of the new pump station and reservoir is currently on going, and Leighton is on site performing geotechnical observation and testing.

The excavations and grading of the reservoir pad required blasting and heavy rock breaking and jack hammering of granitic rock. The relatively steep terrain also presented rock fall hazards. Our geotechnical investigation and subsequent rock fall simulation analyses assisted the design team in preparing the plans and specification to address the potential contractual issues related to hard rock sites and to mitigate the rock fall hazards.

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Project Name: Dominguez Gap Wetlands
Location: Long Beach
Services: Geotechnical
Market Segment: Water Transmission/Treatment

Project Description:

Encompassing 50 acres, the Dominguez Gap Wetlands, located along both sides of the Los Angeles River between Del Amo Blvd. and the 405 Freeway, is considered one of the top five demonstration projects of the Los Angeles River Master Plan. Bio-engineered to treat polluted runoff with riparian habitat before it reaches San Pedro Harbor, this $7-million treatment wetlands and spreading grounds project maintains the integrity of flood protection while introducing new water quality elements, groundwater recharge, restoration of native habitat, pedestrian and equestrian trails, environmental education, and river bike trail enhancements.

As part of an on-call contract with the Los Angeles County Department of Public Works, Leighton conducted a geotechnical investigation involving the advancement of 12 hollow-stem auger borings to depths up to 55 feet below grade. Samples were tested by our in-house laboratory to evaluate geotechnical characteristics such as moisture and density, Atterberg Limits, grain size analysis, shear strength, consolidation, sulfate content, resistivity and pH. Grading was also involved to establish dikes for water collection that will promote the growth of wetland vegetation

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Project Name: Lytle Creek Wastewater Treatment Plant Addition
Location: San Bernardino
Services: Geotechnical, Testing, Inspection
Market Segment: Water Transmission/Treatment

Project Description:

The Lytle Creek Wastewater Treatment and Water Recycling plant provides recycled water, domestic water and wastewater treatment needs to local residents, a Sheriff's facility and Glen Helen Regional Parks. Construction of new additions to this existing facility included a new administration and control building, pump stations, sedimentations tanks, flocculation basins, ditches, settling ponds, and improvements to pipeline easements.

Leighton provided the geotechnical investigation and materials testing and inspection for the construction of the new additions to the Lytle Creek Wastewater Treatment Plant. Our geotechnical investigation consisted of excavating, logging and sampling two air-percussion borings and seven backhoe test pits. With the investigation, we were able to evaluate liquefaction issues, oversize rock and onsite percolation characteristics. We also performed a site-specific evaluation of tertiary effluent for infiltration basins. During the construction phase, Leighton’s testing and inspection services included compaction testing and concrete cylinder sampling and testing.

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