Residential
West Valley Village (Blackstone) - El Dorado Hills

Youngdahl Consulting Group provided a complete Geotechnical Engineering Study for the Blue Shield facilities including the proposed office buildings, retaining walls, access drives and parking areas.  Our study consisted of a refraction seismic rippability survey, site reconnaissance, subsurface exploration, surface and subsurface soil and rock sampling, and field and laboratory tests.  This was followed by recommendations for site preparation and grading, geotechnical design criteria for foundations, retaining structures, slabs-on-grade, asphalt concrete pavements, and underground facilities.  The site was found to be suitable for the proposed construction barring the recommendations. Youngdahl remained onsite during the construction phase to ensure the geotechnical recommendations were incorporated correctly, and to provide quality assurance and special inspection services. 

The Blue Shield Campus consists of four, two-story office buildings, two buildings are 25,000 square feet and the remaining two buildings are 35,000 square feet.  The buildings were constructed on a 29-acre unimproved lot located on a hill crest above Highway 50 in El Dorado Hills, CA.

Youngdahl Consulting Group, Inc. provided geotechnical engineering and materials testing for the construction of a casino in Brooks, California.  Initially our involvement in the project included engineering consultation and design for the expansion of the existing casino, a new wastewater treatment facility including a reservoir and dam embankment to store the treated water, and a two-million gallon steel water storage tank.  We performed slope stability, seepage analysis, and design consultation services for the dam embankment, as well as observation and testing during construction. 

Later consultation and geotechnical engineering services included design recommendations for a hotel and parking structure, including large retaining walls.  This portion of the project consisted of two six-story hotel towers, the expansion of the existing casino building, construction of a three-story parking structure, and site utilities and parking improvements.  The hotel towers were of steel frame construction, and the parking structure of reinforced and post tensioned concrete construction.   

Our geotechnical design services were followed by complete special inspection and testing services to assure compliance with the intent of the geotechnical recommendations and project plans and specifications.

Youngdahl Consulting Group, Inc. has provided numerous geotechnical investigations and geologic hazard reports for multiple expansions at Marshall Hospital complex in Placerville, California.  These projects have included the several hospital expansions to the original hospital including the new x-ray room, gift shop addition, seismic renovation, pneumatic tube project and lounge administration facilities addition.  New construction at the hospital complex has involved construction of the new acute care facility, the primary care facility, parking lots, proposed four story parking structure, SB1953 seismic compliance and an evaluation of the planned four story hospital addition. Our team has successfully undergone the review and approval process of OSHPD for the existing hospital and the construction of new facilities.
Our geotechnical work has involved a review of existing geologic literature including an assessment of mining activity within the hospital area.  We have completed several subsurface investigations which have included geophysical investigation for evaluation of seismic velocities for rippability purposes and development of site specific seismic design criteria.  We have conducted a complete geologic hazard assessment of the site including geologic mapping, slope stability assessment, evaluation of expansive soils conditions and identification of potential geologic hazards. These evaluations have included evaluation of seismological data, calculation of earthquake ground motion, probabilistic seismic hazard, near source coefficients, normalized spectral response, and evaluation of settlement hazards.
Based on the information generated during our study we have provided geotechnical reports which include a description of surface, soil, groundwater, and seismic conditions, conclusions regarding on-site liquefaction potential, recommended seismic design parameters, recommendations for site preparation and grading including dewatering requirements and temporary excavations, design criteria for spread footings and/or deep foundation systems, recommendations concerning slab-on-grade floors, design criteria for retaining walls and pavement design for roadways and parking areas.

Youngdahl Consulting Group provided a geotechnical engineering study, grading plan review, fault study, NOA assessment, and construction observation and testing  for a proposed 990 acre hillside residential development that will include the construction of eight subdivisions (units), a school site, park site, clubhouse and information center. 
The Geotechnical challenges that Youngdahl faced on this project included asbestos dust mitigation, hard rock rippability, fractured rock seepage, compaction of rocky fills, and fractured rock slope stability. Also, the site location straddles the Bear Mountain Fault Zone.

PUBLIC WORKS

The segment of Northgate Boulevard between Arden-Garden and State Route 160 was a two lane road that frequently flooded. The project improved the Arden-Garden Connector/Garden Highway intersection at Northgate Boulevard by widening the bridge and the shoulders, adding retaining walls and bicycle ramps, and reconstructing a recreational trail. 
Youngdahl Consulting Group, Inc.’s services on the project involved performing a subsurface exploration, laboratory testing, and engineering analysis in order to provide foundation design criteria for the new foundations to support the widened bridge, as well as grading and design recommendations for the new roadway and retaining wall construction.  Some of the challenges faced during the design and construction were the limited site access, the proximity of the existing bridge foundations, and construction in an active stream channel.  A limited access tracked rig was used to perform the subsurface exploration, and special recommendations were provided to address re-compaction of the material removed around the existing bridge foundations during construction of the new footings.

Youngdahl Consulting Group, Inc. has been retained by EID under numerous annual contracts to provide geotechnical engineering, inspection and materials testing for various treatment, storage, and pipeline facilities throughout the EID service district. 

Quality assurance and inspection services for construction of pipeline and associated pump stations include earthwork quality assurance testing, monitoring of pipeline installation, pipe bedding and shading, and compaction testing during backfill operations.  Asphalt observation and quality assurance testing was performed on the paved areas.  When necessary we sampled and tested the concrete and grout materials used.