Photo courtesy of Caltrans
More than 60 lane mi. of SR 27 are being repaved and approximately 40,000 linear ft. of guardrail will be upgraded.
C.A. Rasmussen Inc. started work on the California Department of Transportation's (Caltrans) $59.5 million Topanga Canyon Boulevard Pavement Project, which covers more than 18 mi. on State Route 27 (SR 27) from the Pacific Coast Highway in Malibu to Devonshire Street in Chatsworth in the San Fernando Valley (Los Angeles County).
More than 60 lane mi. of SR 27 are being repaved and approximately 40,000 linear ft. of guardrail will be upgraded. The project is upgrading curb ramps and crosswalks to the Americans with Disabilities Act (ADA) standards. This includes 26 traffic signals, 200 repaired and replaced curb ramps and nearly 30 pedestrian push buttons. Additionally, the work will add more than 20 landscape control locations, nearly 50 transit stop improvements and two bicycle drainage gates.
The project is expected to be delivered in fall 2027.
David Miraaney is serving as the project manager; the project engineer is Nguyen Hua and Refugio Dominguez is Caltrans' design engineer on the project.
"There were no design challenges to this project," said Dominguez. "The main challenge was community support of this project. [Many people] are concerned about traffic delays during construction and how it will impact their daily commute. Also, there are existing guardrails that need to be upgraded since they have been damaged and/or do not meet the safety requirements. Residents do not want shiny new metal guardrails on the road. This concern is typically found in the rural and mountainous area of Topanga Canyon."
The new guardrails, known as the Midwest Guardrail System (MGS), will be colored reddish-brownish to avoid a shiny appearance and essentially match the color of the existing guardrail.
The overlay will extend the lifespan of the pavement by 10 years, with a top layer of RHMA and a bottom layer of HMA.
"There is a 9,000 feet highway segment in the mountainous area that we are not doing the typical cold plane and overlay," said Dominguez. "We are just overlaying it because it is in a sensitive environmental area. The cold plane could generate dust or pavement material [shavings] that could reach the nearby creek."
C.A. Rasmusen crews started work at the north end of the project near Devonshire Street and are making their way south to Malibu, with construction taking place day and night. Caltrans is aware that construction is impacting the community.
"Residents and businesses located near the freeway are advised to anticipate noise, vibrations and dust associated with construction activities," said Diana Jimenez, a public Information Officer of Caltans District 7 (Los Angeles and Ventura counties).
Caltrans is making every effort to mitigate noise associated with construction activities by installing a noise reduction barrier around the plant location.
"Noise levels will not exceed state, federal and city regulations," stated a press release. "Water trucks minimize dust during working hours and dump truck driver will minimize backing up operations to reduce back-up alarm noise."
The DOT is planning detour routes to help deal with traffic problems.
At this point, C.A. Rasmussen has initiated early operations and is ramping up its efforts.
"The early construction challenge is to coordinate with current and future contracts by other agencies within the same project limit to minimize the delay impact," said Caltrans Transportation Engineer Elizabeth Martinez, the acting resident engineer of the project. "Saw-cut operations started March 14 and resumed on April 8. The work is on schedule, progressing as planned. Groundwater is not anticipated at the shallow depths excavated at 2 feet. Excavation operations will be a maximum of 1.85 feet in depth into existing pavement sections. There will be no significant soil disturbances. Underground utility clearances are being managed by the contractor. Other work on CA 27 not part of this contract [and] will be coordinated within Caltrans to avoid work conflicts."
This is a tight work zone, with half of the project going thru the canyon. The road is a two-lane highway, one lane in each direction.
Safety measures are being taken to protect workers and motorists via proper lane closures and signage following Caltrans standard plans that are based on MUTCD guidelines, including speed reduction limit signs around construction areas as needed.
"We are partnering with the California Highway Patrol to have officers on-site during construction operations," Martinez. "Placement of message signs containing notice of anticipated workdays are done one week in advance of operations. Caltrans responds promptly to finding proper solutions to any issue with the contractor."
The repaving is based on asphalt lanes, save the proposed bus pads, which will be changed from asphalt to concrete to provide a stronger pavement due to the braking action of the buses.
In regards to the new bus pads, they are based on a 0.85 ft. Joint Plane Concrete (JPCP), a 0.5 ft. Lean Concrete Base (LCB) and a Rapid Set 05 ft. Class 3 aggregate base.
"The challenge is minimizing impact to traffic and local businesses during business hours," said Martinez. "The work is being performed at night, with detour routes and signs as needed. We are limiting closures to two miles; or to ½ mile on one-way reversing traffic control setups. One-way reversing traffic-control lane closures will not exceed five minutes for each direction. Another challenge is keeping noise to a minimum at night. Caltrans can offer hotel stays away from the site of construction for those impacted by noise."
The length of road sections that are being repaired will depend on production rate, but will be limited to 2 mi. per-closure
"One closure is currently planned per-night in one direction," said Martinez. "Concurrent closures will be more than five miles apart. At least one through traffic lane will remain open in each direction of travel or one lane will remain open for use by both directions of travel [wait times will not exceed more than five minutes at a time]. Cold planing and placement of new pavement sections will be scheduled to be done in one shift. Cold planing will consist of removal of existing asphalt pavement, pavement markers, pavement delineation and pavement markings."
The road removal is between 0.15 ft. to 0.25 ft. The upgraded lanes will have a top layer of RHMA and a bottom layer of HMA, using a 0.15-ft. rubberized hot mix asphalt to reduce noise (friction between the road surface and the tires) and a 1 to 0.1 ft. regular hot mix asphalt.
There will only be an overlay at environmentally sensitive areas and no pavement removal to avoid dust particles and road material from entering the adjacent creek.
For the cold planing operations, crews are using cold planer/milling machines, sawcut machines, grinders, asphalt distributors, skid steer loaders, sweepers, asphalt pavers, backhoes, compaction rollers, striping equipment and light towers.
Prior to paving, 52 new bus pads and 200 ADA curb ramps will be constructed.
"Guardrail upgrades will be done after roadway paving," said Martinez.
The relationship between the Caltrans and C.A. Rasmussen management teams, said Martinez, "is very collaborative."
The number of construction workers from C.A. Rasmussen and the subcontractors, local and regional, shall increase as the operations expand.
The amounts of materials to be excavated and brought in are still being tabulated. CA materials are being recycled.
Maintaining and repairing equipment rapidly is crucial to production.
"The contractors have oilers and personnel that come by daily to refuel the equipment and lubricate any machines if needed," said Martinez.
"This project is needed to rehabilitate the existing pavement and add another 10 years of life span," said Dominguez. "It started at the end of March 2016 with a scoping field review and constructability review ensued in mid-October 2016. A Capital Preventive Maintenance Project Report [CAPM-PR] for Programming was approved in June 2017. The project was subsequently programmed by California Transportation Commission in 2018." CEG
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