El Dorado County, California
This currently in-process project will replace the existing single-span, steel suspension bridge (originally constructed in the 1800’s, replaced in 1939, and rebuilt in 1985 and 1990) and eliminate the steep roadway approaches to provide all weather access and decrease transit times between the communities of Placerville and Mosquito. The proposed bridge is an 1180-foot long balanced cantilever structure consisting of three spans (322 ft – 536 ft – 322 ft) of cast-in-place/pre-stressed concrete segmental box girder construction. The bridge deck will be about 495 ft above the South Fork American River and descend about 40 ft from southeast to northwest. The abutment foundations will be established about 10 to 20 ft below existing ground surface. The pier foundations will be established in the steep canyon slopes about 160-170 ft above the river requiring cuts on order of 50-60 ft high. Retaining walls are also planned at Abutment 1 to retain approach fill. Geotechnical services included permitting, geologic review/reconnaissance, geophysical surveys, twelve test borings, soil and rock core sampling, laboratory testing, petrographic examination of rock cores, drafting and preliminary geotechnical evaluation/analysis. The field exploration program required clearing the proposed pier locations, constructing temporary platforms and use of a helicopter to transport the drill rig to pre-selected boring locations.
The City of Sacramento contracted with CAInc to provide professional engineering services to perform traffic counts and preliminary pavement coring on the five roadway segments within the city. The traffic counts will be used to determine existing traffic indexes and the pavement cores will be used as a basis for overlay/rehabilitation design which will be completed in the final design phase. Project boundaries for each road consist of:
- Folsom Blvd – From Power Inn to Florin Perkins Road
- Mack Road – Morrison Creek Bridge to Stockton Road
- J Street – From 16th Street to 30th Street
- Natomas Boulevard – North Park Drive to Elkhorn Boulevard
- Grand Avenue – Rio Linda Boulevard to Marysville Boulevard
CAInc is preparing Pavement Design Memorandums for the five projects, which includes coring the pavement to measure existing asphalt concrete and aggregate base, evaluating the condition of the existing pavement, and providing rehabilitation recommendations and overlay options for each road. Recommendations include: Full Depth Reclamation (FDR), Deep Lift HMA Replacement, New Pavement Sections, Reduced Traffic Index Option, and Full Depth Reclamation/Cold In-Place Recycling (CIP).
CAInc prepared/submitted a Preliminary Foundation Report for the for the type selection phase of the project. This report summarizes subsurface foundation conditions and provides laboratory test results, seismic data, preliminary LPile parameters, the Log of Test Borings preliminary foundation information/recommendations and construction considerations. Tentatively, large diameter cast-in-drilled-hole (CIDH) piles socketed into rock are considered appropriate at Abutment 1, Pier 2 and Pier 3. Shallow spread footing foundations founded in the underlying rock are considered appropriate at Abutment 4, likely with some slope “augmentation” such as rock anchors/bolts. CAInc will prepare a Foundation Report following bridge type selection that will provide final foundation recommendations based on defined foundation type and load data.
Roseville, Placer County, California
The project involves widening Washington Boulevard from Sawtell Road (south) to Pleasant Grove Boulevard (north) and the replacement of the Union Pacific Railroad (UPRR) Andora Underpass bridge structure. Based on conversations with Mark Thomas & Company, the UPRR bridge replacement is expected to consist of a longer and wider multi-span structure with either two or four spans. A shoo-fly is planned to allow staged construction of the railroad bridge. For the new railroad bridge, Crawford & Associates, Inc. (CAInc) prepared a Preliminary Foundation Memorandum for the preliminary engineering phase and will prepare a Foundation Report for the final design phase. Design of the railroad bridge is expected to be in accordance with the American Railway Engineering and Maintenance-of-Way Association (AREMA) Manual for Railway Engineering. CAInc will prepare the reports consistent with current Caltrans format.
Albany, Alameda County, CA
CAInc prepared a Pavement Report for the City of Albany Pavement Rehabilitation Project – Phase I. The City had a limited budget and time constraints, making it important for the CAInc team to work quickly and efficiently to provide recommendations.
CAInc completed a single pavement core at each roadway segment to evaluate existing hot mix asphalt and aggregate base thicknesses, and to collect samples of the subgrade soil for R-value testing. Rehabilitation options, including Roller Compacted Concrete, traditional overlay, and Full Depth Recycle Rehabilitation recommendations were provided. CAInc provided new pavement section recommendations and pavement overlay options, which would fit within the City’s budget and schedule.
CAInc also recommended removing failed areas of pavement and performing a slurry seal to extend the life of the pavement.
Del Norte County, CA
The purpose of the Requa Road at Hunter Creek Bridge Replacement Project is to improve public safety and hydraulic capacity of Hunter creek by replacing the existing structurally deficient, two-lane, three-span bridge (138 feet long by 28 feet wide) with a new, two-lane, single-span bridge elevated above the flood plain and constructed approximately 25 ft south of the existing bridge on a downstream alignment. The bridge replacement with elevated roadway approaches along the existing Requa Road alignment could involve elevating up to 800 feet of connecting low lying segment of Requa Road above the flood plain. This project will receive federal funds through the Federal Highway Administration (FHWA) Highway Bridge Program (HBP) for the purpose of removing this bridge from the bridge replacement eligibility list.
CAInc/Taber prepared a Preliminary Geotechnical Report (PGR) and Preliminary Foundation Report (PFR) for the project. The PGR contains a description of site, project description, existing geologic conditions, subsurface conditions, and earthquake data. Recommendations included CIDH Piles, embankment approaches, roadway realignment alternatives, and preliminary pavement sections. The PFR includes a more in-depth review of subsurface conditions, including results of Cone Penetration Test Borings, Seismic Refraction Survey, and groundwater conditions. An evaluation of scour potential, corrosivity testing, and site seismic conditions, including ground motion, a site specific seismic hazard analysis, liquefaction potential, seismically induced settlement, and seismic slope instability, were addressed. Foundation recommendations include Cast-In-Steel-Shell (CISS) Piles and Ground Improvement and Spread Footing Foundations.
Humboldt County, CA
The existing Williams Creek Bridge was built in 1920 and is a single span, 40-foot long, 22-foot wide, concrete T-beam structure with concrete diaphragm abutments. The proposed new bridge will be in a similar road alignment with the new deck grade slightly higher than existing. The approach roadway alignment will be widened and raised slightly to accommodate the new bridge.
For the project, CAInc reviewed geologic and seismic maps; drilled, logged, and sampled test borings; and completed lab testing. We provided scour considerations and corrosion evaluations, determined liquefaction and cyclic softening potential, and provided foundation recommendations for the bridge. Completed two R-value tests on bulk samples from each bridge approach and provided recommendations for preliminary pavement sections.
Humboldt County, CA
The existing 15 span bridge, built in 1965, is approximately 302 ft long by 10.7 ft wide and is a low water crossing that was built after two previous bridges supported by timber and/or steel piles were washed away. The piers and abutments of the existing bridge are each supported by three H Piles with a reinforced concrete deck. The existing deck is damaged with exposed reinforcing bars. A new alignment was introduced by the Engineer and will move approximately 1900 ft upstream from the existing alignment.
The proposed structure is planned as an 8-span structure approximately 1483 ft long and 25.25 to 31.25 ft wide. The planning study shows the first 5 spans to be a Cast-In-Place pre-stressed box girder approximately 1043 ft long. The second 3 spans are shown as a 440 ft long Cast-In-Place pre-stressed box girder approach structure. Abutment 1 is shown supported by a spread footing with tie-downs into rock. Piers 2-6 are shown supported by single, large 10 ft diameter Cast-In-Drilled-Hole (CIDH) piles with casing. Piers 7-8 and abutment 9 are shown supported by driven piles. The new deck grade will be higher than the existing low water crossing.
Holmes-Larabee over Eel River Replacement Bridge Project
Humboldt County, CA
The existing multi-span bridge, built in 1937, is approximately 331 ft long by 10 ft wide. The existing bridge is a low water crossing originally built with a timber deck supported by timber piles. Humboldt County replaced the bridge deck in around 1960 with concrete and reinforced steel (railroad) rails. The existing deck is severely abraded with transverse ruts and exposed reinforcing bars. A 2013 inspection of the bridge resulted in closure due to structural deficiencies. A new alignment was introduced by the Engineer and will move approximately 25 ft upstream from the existing alignment.
The proposed structure is planned as a 12-span structure approximately 1980 ft long and 25.25 to 31.25 ft wide. The planning study shows the first 6 spans to be a Cast-In-Place post tensioned box girder approximately 1200 ft long. The second 6 spans are shown as a 780 ft long box girder approach structure. Abutment 1, Piers 8-12, and Abutment 13 are shown supported by driven piles. Piers 2-7 are shown supported by single, large 10 ft diameter Cast-In-Drilled-Hole (CIDH) piles. The new deck grade will be higher than the existing low water crossing.
For both bridges, CAInc is currently preparing a Preliminary Foundation Report (PFR) and ISA for Phase I of the projects. The PFR includes a summary of field exploration, site geology, groundwater, scour, and corrosion evaluations, and site seismic conditions. Preliminary foundation recommendations and construction considerations will be provided as testing and analysis is completed.
Rancho Cordova, California
The City of Rancho Cordova plans to expand the west side of the existing bridge to accommodate an additional southbound through lane. The bridge superstructure will be a precast, prestressed, post-tensioned, bath-tub girder. Additional fill will be placed adjacent to the existing approach fill to accommodate this expansion. Deep foundations at each abutment and the bent will support the bridge improvement loads.
For the project, CAInc prepared a Foundation Report, a Structure Preliminary Geotechnical Report, a Materials and Geotechnical Design Report, Initial Site Assessment, and Aerially Deposited Lead Investigation Report. To prepare the reports, CAInc reviewed previous studies and plans of the overcrossing, bridge design plans, and geologic/seismic maps of the site; drilled, logged, and sampled test borings and performed laboratory testing on soil samples; and performed engineering analysis.
Recommendations included HP 14 x 89 piles to support the bridge improvements. CAInc determined compressive resistance and tension/uplift resistance of the H-piles using the A-Pile computer program developed by Ensoft, Inc. Settlement calculations, lateral load analysis, and approach fill earthwork were also provided.
Results of the Initial Site Assessment (ISA) found low risk regarding soil/groundwater contamination and hazardous materials. Recommended groundwater sampling at the boring locations near the proposed bridge foundation excavations to be screened for potential volatile organic compounds.
For the Aerially Deposited Lead (ADL) study, CAInc selected fourteen ADL test locations within the project limits. The locations were selected based on potential soil disturbance during construction. A total of 27 soil samples were collected in discrete runs and sealed in sterile glass containers immediately after extraction from the ground. The containers were labeled and placed on ice. Samples were logged and observed closely to maintain an accurate chain-of-custody until final delivery to a California certified analytical environmental laboratory. All samples tested had total lead results at concentrations above the 1.0-milligram per kilogram (mg/Kg) detection limit. The highest reported total lead concentration from all tests conducted was 57.0 mg/Kg. This value is less than the EPA Region 9 RSL for lead in industrial soil (800 mg/Kg). None of the samples tested exceeded the California-modified soil screening level for total lead in industrial soil (320 mg/kg).
Lathrop, San Joaquin County, CA
CAInc prepared a Draft Pavement Design Report for Lathrop Road Widening project in Lathrop, California. The project consists of Widening Lathrop Road about 30 ft to the north, improve the existing pavement to meet a traffic index of 11, convert the existing east bound shoulder into a travel lane, new flatwork, raised median, and sidewalk, utility improvements, and minimal right-of-way acquisition.
CAInc cored the pavement at 20 locations along Lathrop Road to measure the existing asphalt concrete and aggregate base thicknesses and collected subgrade samples for R-value and mix design testing. CAInc evaluated the condition of the existing pavement by walking the roadway and reviewing the pavement cores. Completed the following laboratory tests on representative soil and pavement samples obtained from the fieldwork:
- R-value (CTM 301)
- Compaction Testing (ASTM D1557)
- Unconfined Compressive Strength (ASTM D1633)
Based on a review of the pavement and results of laboratory testing, pavement recommendations were provided. Options included Hot Mix Asphalt Overlay, Full Depth Rehabilitation (FDR), Full Depth Reclamation/Cold In-Place Recycling (CIP), Deep Lift HMA Replacement, New Pavement Sections, Reduced Traffic Index Option, and Roller Compacted Concrete.
Santa Clara, California
The City of Santa Clara contracted with CAInc to provide professional engineering services to provide design verification of Full Depth Reclamation (FDR) and ensure quality control during the construction of the project for three roads within the city. The majority of the roads were in poor condition with areas of severe alligator cracking, block cracking, transverse and longitudinal cracking, and rutting.
CAInc prepared a Full Depth Reclamation Design Verification Memo verifying the City’s internal FDR design and also provide mix design recommendations. To prepare the report, CAInc cored the pavement along the three roads within the project limits to measure the existing asphalt concrete and aggregate base thicknesses and collected subgrade samples for R-value and mix design testing. CAInc evaluated the condition of the existing pavement by walking the roadway and reviewing the hot mix asphalt (HMA) pavement cores. Recommendations included FDR Design verification and Construction guidelines review.
CAInc’s inspector/engineer observed, verified, and performed sampling and testing during the FDR process. The field technician/project engineer performed multiple tasks while on site including observation of pulverization, moisture content sampling and verification, placement of cement, and compaction testing.
Davis, Yolo County, CA
CAInc prepared Pavement Design Reports for L Street and Mace Boulevard to provide the City of Davis with available rehabilitation options for the roadway segments within the City.
CAInc cored the pavement at nineteen locations along the 240,900 sq. ft. section of L Street to measure the existing asphalt concrete and aggregate base section thicknesses and collected subgrade samples for R-Value and mix design testing. CAInc evaluated the condition of the existing pavement by walking the roadway and reviewing the pavement core data. Completed the following laboratory tests on representative soil and pavement samples obtained from the fieldwork:
- R-value (CTM 301)
- Unconfined Compressive Strength (ASTM D1633)
Provided overlay options, recommendations for Full Depth Rehabilitation (FDR), Cold Central Plant Recycling (CCPR), Roller compacted concrete, Deep Lift HMA Replacement, new pavement sections, and considerations for reduced traffic index options. The project involved existing grade constraints, existing high crown issues, changing traffic index and patterns, varying existing pavement section thicknesses, and both industrial and residential situations.
CAInc cored the pavement at three locations along the 218,200 sq. ft. section of Mace Boulevard to measure the existing asphalt concrete and aggregate base section thicknesses and collected subgrade samples for R-Value and mix design testing. CAInc evaluated the condition of the existing pavement by walking the roadway and reviewing the pavement core data. Completed the following laboratory tests on representative soil and pavement samples obtained from the fieldwork:
- R-value (CTM 301)
- Unconfined Compressive Strength (ASTM D1633)
- Deflection Testing (CTM 356)
Based on discussions with the City and the design team, the project will proceed with Full Depth Reclamation (FDR) with an HMA wearing course for both the travel and bike lane. The City selected a Traffic index of 9 for the travel lanes and a Traffic Index of 5 for the bike lanes. Pavement rehabilitation recommendations were provided to improve the existing pavement condition, mitigate reflective cracking, and increase the traffic index/design life of the pavement.