Contractors are making progress on the $54 million SR 52 Pavement Project in San Diego, addressing settlement issues near Convoy Street. Compaction grouting and an eastbound auxiliary lane are being added to improve safety and traffic flow. Completion is expected by spring 2027.
Caltrans photo
Steel rebar is placed before an auxiliary lane on SR 52 is paved
The California Department of Transportation's (Caltrans) $54 million State Route 52 Pavement Improvement and Auxiliary Lane Project is bringing numerous improvements to a 3.9-mi. stretch of the highway near Convoy Street in San Diego.
Work by the joint venture of Coffman Specialties Inc. and Condon-Johnson & Associates began in March 2024. Project completion is anticipated by spring 2027.
The project is financed through the Federal Highway Trust Fund and the State Highway Fund.
The project is designed to resolve pavement issues near Convoy Street between Interstate 805 and State Route 163 and is adding an eastbound auxiliary lane from Interstate 15 to Santo Road. In addition, eight maintenance vehicle pullouts (MVP) will be installed to reduce highway work exposure during landscaping activities, and 13 existing metal beam guardrails will be upgraded to Midwest Guardrail Systems with steel posts.
"The settlement over the Old Miramar Landfill is causing uneven pavement conditions," said Steve Welborn, Caltrans public affairs manager. "Construction crews have performed compaction grouting as ground improvement mitigation and will place an asphalt overlay, and that will level the uneven pavement and improve ride quality.
"This will provide comfort and safety for drivers and improve the structural performance of the pavement. Additionally, by implementing the subsurface ground improvement, projects will not be needed to correct the uneven pavement using frequent emergency overlay projects in the near future."
The added lane will help with congestion.
"Eastbound I-15 to Santo Road is experiencing approximately 6,000 vehicles per hour during peak travel periods," Welborn said. "The eastbound auxiliary lane is expecting to improve the operational flow of traffic as the I-15 connectors merge onto SR-52."
The project's been in the planning stages since 2017, although discussions began as early as 2014. It was launched in the state's Systems Highway Operations Protection Program (SHOPP). The project was designed by Caltrans District 11 based on recommendations from the agency's Office of Geotechnical Design South.
"It basically identified they would like to address 30 years of settling," Welborn said.
"Segments of SR 52 are underlain by the old South Miramar Landfill, both east and west of Convoy Street from post mile 5.1 to 6.2," said Roger Carlin, Caltrans engineer. "Continued settlement is due to biodegradation and consolidation of landfill materials. The compaction grouting design was based on the depths to the bottom of the landfill, inferred from past topographic maps, prior to the construction of SR-52."
Caltrans has performed overlays of the lanes on several occasions above the settlement, as well as compacting operations.
"The nature of the subsurface landfill material within the project areas is such that future settlement, and the extent to which it should be expected, is far less predictable than typical site soil conditions," Carlin said. "Prior to this project, overlay projects were being implemented every three or four years to address settlement. The plan is that this subsurface compaction grouting will provide stability for a time frame worthy of the state's investment."
"Subsurface investigation in the landfill material is difficult due to the environmental and health concerns with generating potentially hazardous waste and fumes during the drilling process," he added.
As of March 20, the following project elements are complete: compaction grouting and construction of the eastbound auxiliary lane. Crews are working on rubberized hot-mix asphalt work, drainage, electrical and striping improvements. Over the next year, efforts will focus on landscaping and project closeout.
The crews are dealing with several challenges.
"One is unknown existing landfill conditions for compaction grouting and unsuitable soil under the auxiliary lane," said Jake Stelten, Caltrans project manager. "Early on, the project drew on the history of current conditions and best solutions and best practices. The design team worked with the joint venture team to develop the construction plan and techniques."
The effort to reduce the uneven pavement settlement near Convoy Street between I-805 and SR 163 is making solid progress, with crews placing compaction grouting to slow the pavement settlement.
"The strategy is to support the pavement by pouring shafts of compaction grout down to soil that is more stable," Stelten said. "The design utilizes a grid pattern for distributing the compaction grouting shafts. There are thousands of holes in the ground. Crews are drilling down to depths of 30 to 60 feet. Once the holes are dug, the grout is injected in. They do this over and over again until the stabilization system is created. The goal is to create a better grid system to support the pavement section."
Equipment operators are using KLEMM and ABI drill rigs, APE vibratory hammers, Cemen Tech volumetric mixers, DSS and Belgrade cement silos, and Putzmeister (DEUTZ) and KLEIN concrete pumps.
Meantime, "The 1.3-mile eastbound auxiliary lane from I-15 to Santo Road is being achieved by median widening. The previous lanes will shift towards the new median lane and is allowing what was the previous outside general-purpose lane to act as a new auxiliary lane," Stelten said. "The median concrete barrier (Type K) will be removed and replaced with a high-tension cable barrier (HTCB) where feasible. The HTCB will be stained dark brown to reduce any visual impacts."
The asphalt lane is based on 1.2 ft. Class 4 AC, 0.40 of cement-treated permeable base and 0.75 jointed plan concrete pavement. Standard construction techniques are being employed. Equipment used includes pavers, rollers, excavators, skid steers and loaders.
The eight maintenance vehicle pullouts are within the SR-52/Convoy Street interchange and along the SR-52 main lanes near SR-163 and I-15. They are 12-ft. wide and 85-ft. long, including the tapers.
To minimize traffic impacts, Caltrans follows a traffic management plan that consolidates construction activities requiring closures, resulting in fewer lane, ramp and freeway closures for the public.
When similar work was performed in 2020, Caltrans was able to close the highway, which was doable based on reduced traffic because of the pandemic.
"We are now doing this with increased traffic, and we feel that eastbound and westbound weekend closures are the best method to minimize traffic impacts," Carlin said. "The traffic plan is working."
The highway will open to traffic in June, at which point the seven-month plant establishment phase will begin.
Typical days have 40 or more joint venture and subcontractor employees on site, which includes four drill rig crews operating simultaneously.
"This project does not require salvage or recycling of materials," Welborn said. "However, the contractor can recycle materials if the material specifications are met for the reuse of materials."
Subcontractors include Statewide Safety Systems, Payco Specialties Inc., Ace Fence, Diversified Landscape, Cindy Trump Inc., MCS, Cooper Engineering, Coral Construction, Select Electric, Golden West Construction, ABSL Construction, Natina and Maneri Traffic Control.
Project items include: paving; compaction grouting; traffic control; stormwater, irrigation and landscape drainage; signs; striping; Midwest guardrails; high-tension cable barriers; Zoneguard barriers: CCTV cameras: fiber optic systems; and traffic monitoring stations.
The Caltrans District 11 management team includes Acting Project Manager Jake Stelten, Resident Engineer Tai Lam and Design Manager Roger Carlin.
The earthworks operation generated 1,600 cu. yds. of materials.
New construction materials include: 30,000 tons of AC, 56,000 cu. ft. of compaction grouting, 2,350 cu. yds. of concrete pavement, 4,730 cu. yds. of Class 4 aggregate subbase, 5,100 cu. yds. of Class 2 aggregate base, 12 tons of fog seal and 1.5 tons of miscellaneous iron and steel. CEG
(All photos courtesy of Caltrans.)
Irwin Rapoport
A journalist who started his career at a weekly community newspaper, Irwin Rapoport has written about construction and architecture for more than 15 years, as well as a variety of other subjects, such as recycling, environmental issues, business supply chains, property development, pulp and paper, agriculture, solar power and energy, and education. Getting the story right and illustrating the hard work and professionalism that goes into completing road, bridge, and building projects is important to him. A key element of his construction articles is to provide readers with an opportunity to see how general contractors and departments of transportation complete their projects and address challenges so that lessons learned can be shared with a wider audience.
Rapoport has a BA in History and a Minor in Political Science from Concordia University. His hobbies include hiking, birding, cycling, reading, going to concerts and plays, hanging out with friends and family, and architecture. He is keen to one day write an MA thesis on military and economic planning by the Great Powers prior to the start of the First World War.
Read more from Irwin Rapoport here.
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