Highway and Bridge Projects

The Avenue S Corridor Improvement Project comprised the replacement of a two lane bridge on Avenue S over the Union Pacific Railroad tracks with two new bridges totaling six lanes. The realignment of 20th Street East and improvements to Avenue S from the new bridge to the Antelope Valley Freeway (Highway 14) approximately 1.5 miles west of the project area were part of the project development.The new bridges consist of cast-in-place, post-tensioned, concrete box girders supported on embankment abutments on the ends with a pair of intermediate bent pier walls.  Pier/pile foundations support the abutments and bents.  Earth Systems Southern California performed a geotechnical engineering investigation which addressed surface and subsurface soil/bedrock conditions, groundwater, regional geology, site geologic conditions, and geologic hazards.  Recommendations provided included: seismic design parameters, slope stability, site preparation, utility trenches, conventional foundation design, drilled pier foundations, pier construction and installation, retaining wall design, and pavement sections.   During construction of the infrastructure improvements, Earth Systems Southern California’s certified technicians performed compaction testing of the bridge approach embankment and Avenue S/20^th Street East street improvements, along with special inspection and materials testing of the bridge construction operations. 

Our personnel performed a geotechnical engineering study which addressed the rehabilitation or replacement of the Higuera Street Bridge.  The bridge over San Luis Obispo Creek was composed of reinforced concrete and steel girders; the deck was supported by mortared historical stone abutments from the early 1900’s.  The study provided data regarding the wall condition, subsurface conditions and seismology; the report presented recommendations for replacement of the abutments with new cantilevered abutments, resupport of the bridge deck on drilled caissons with the stone abutments to be left in place, or reinforcing the stone abutments with post-tensioned archors.  Subsequently, post-tension anchored abutments and pre-stressed deck panels were utilized to reconstruct the bridge.  Our technicians provided grading observation and testing, and laboratory testing for the project during construction.

The augmentation of the historic Bridge Street Bridge was accomplished to meet seismic safety requirements.  Dating from the early 1900’s, the bridge spans the Arroyo Grande Creek. The north span is a truss structure extending the entire creek width, and the south span is a steel girder structure spanning a short flood plain area.  Concrete abutments support the bridge at each end, and an offset pier on the south bank supports the connection between the two spans. The augmentation entailed construction of structural facing and encasing the bridge abutments and the offset pier in structural elements designed to accommodate seismic forces.  New foundations were constructed to support the weight of the new structural elements and to resist the lateral seismic loads of the entire bridge structure. For this project, Earth Systems Pacific performed a soils engineering investigation involving site reconnaissance, field exploration, laboratory analysis of samples, geotechnical engineering analysis.   We developed recommendations for the schematic design of foundations, and these recommendations complied with Caltrans design practices as they apply to seismic upgrades of historic bridges. 

The previous bridge over the Salinas River at Las Pilitas Road was replaced with a cast-in-place concrete structure supported by drilled cast-in-place concrete caissons.  The road was realigned and earthen embankments were constructed on each side.  The new bridge spans approximately 200 feet.  Earth Systems Pacific was retained to perform sampling and testing of concrete and rock during construction.

The new Western Gate Ranch Bridge crosses Barranca Honda Creek, and replaces a metal bridge, two corrugated steel culverts, concrete features, and a former dip crossing.   The new bridge is a simple span, prefabricated steel bridge designed for H-20 loading, and of 90 feet in length and 13 feet in width.  Rock rip-rap was placed as erosion protection on the creek bank at each abutment.  As the new bridge is longer than the previous bridge, the realignment of a bend in the road at the bridge's west end was accomplished.  Earth Systems Pacific's geotechnical engineering investigation included site reconnaissance, field exploration, laboratory testing, and analysis of data.  Subsequent geotechnical recommendations were provided for foundations including conventional and drilled cast-in-place caissons, for lateral pressures and wing walls, and earthwork and abutment backfill.  During construction operations, our personnel performed foundation excavation observations, certification of grading operations, and inspection of concrete placement.

The Fourth Street Overcrossing project involved the reconstruction of the existing two-lane overcrossing structure and interchange configuration.  The replacement structure is seven-lane and approximately 97 feet wide.   Geotechnical services focused on the removal and replacement of the existing structure, the construction of a southbound auxiliary lane, and the removal and realignment of on- and off-ramps. Our personnel performed a soils engineering investigation and during construction provided special inspection of construction materials and observation and testing of the grading operations.

The reconstruction of Dillon Road consisted of the removal of approximately one-quarter mile of the existing roadway asphalt and baserock section, and preparation of the subgrade soils to receive the new pavement section, between Vista Del Norte and Avenue 44.  Our office performed the initial evaluation and investigation to measure the existing pavement section, obtain samples, and prepared a written report addressing site soil conditions, drainage, and providing design criteria for the replacement paving section.  Our work during construction consisted of field density testing of the native soil/subgrade, aggregate baserock, and asphalt.  Laboratory testing consisted of R-value testing, compaction curves, and gradation/extraction.

The Washington Street Bridge stretches over the Whitewater River Channel in La Quinta. Our firm was retained to perform a soils engineering investigation for the widening to six lanes of the original two-lane bridge. The project included roadway improvements for approaches to the bridge. A soils engineering investigation, and testing and inspection of construction materials, were performed by our firm for this bridge widening.