Work just began on the pavement rehabilitation of I-8 from Crestwood Road to Imperial County Line in Southern California in the California Department of Transportation’s District 11 (San Diego and Imperial County), a $34.885 million contract that was awarded to Coffman Specialties Inc.
The rural project covers 16.6 mi. (26.7 km) of an east-west road (Post Miles 61.2 to 77.8, two lanes in each direction) and nine bridges. This stretch of roadway was built in stages between 1967-1971 and has experienced some renovation work in the past.
“Between 168,000 to 136,000 per-day travel on this section of I-8 daily,” said Edward Cartagena, media information officer, Caltrans District 11. “The pavement has exceeded its service life and beginning to revel. The expected lifespan of the new roadbed is 10 to 15 years. Caltrans maintains and improves the state’s highway system on an ongoing basis as needed.”
The contract start date was April 14, 2015 and the current contract completion date is February 16, 2016. Major items of work for the contract include removing approximately 4 in. (10 cm) of existing roadway pavement and replacing it with new AC pavement, removal and replacement of AC dike along the shoulders for stormwater control, installation of approach slabs at each bridge structure, and removal and replacement of the existing guardrail.
“This project will be a challenge for us,“ said Jim Coffman, the firm’s senior vice president. “The existing roadway has been overlaid multiple times or patched and this can be a challenge when we start milling to remove the top 4 in. (10 cm) of pavement. The profile grain might be a challenge depending on what is going to happen based on the overlays. We’re in the process of surveying the existing roadway to ensure that we will provide the right profile once we start our operations.”
The typical thickness of the existing pavement section is approximately 9 in. For the new road base, .33 ft. of the upper pavement section is being removed and replaced with a base layer of .1 ft. of 3/8 in. Type A Conventional Hot Mix Asphalt, a SAMI interlayer approximately 3/8 in. thick, and finally a cap layer of .2 ft. of 3/4 in. Rubberized Hot Mix Asphalt.
“Another one of the challenges is that we’re in the mountains and 60 miles away from the asphalt plant,” said Coffman, “so whatever we mill out with a cold planer, we have to put back that same shift. The timing of deliveries will be critical. We will have to precisely measure the work as we’re putting in three different layers as required. We’re also required to initial profile the existing surface and meet a certain criteria for smoothness.”
The plan is to do the work one lane at a time in order to minimize the impact on traffic.
“We’ll do the lane and then the shoulder,” said Coffman. “We get to close one lane in each direction during the construction period.”
The Caltrans contract does not require the use of concrete barriers, but Coffman Specialties is looking at setting up some moving barrier systems to follow the work — a plan that it will discuss with Caltrans.
“We’ll also use crash attenuator-type trucks behind the work to alert people to stay out of the lane,” said Coffman, “so it will not only just be cones. Protecting the public and our crews is a priority.”
When the project is completed, Coffman expects that about 175,000 tons (158,757 t) of asphalt will be removed and replaced with 55,000 tons (49,895 t) of Type A asphalt, 15,000 tons (13,607 t) of SAMI, and 115,000 tons (104,326 t) of rubberized asphalt.
“The material we are removing will not be recycled,” he said. “In California you have a different situation because there are very few places where you can mine aggregates due to environmental constraints, and most of those sites, because of the rehabilitation work that has been ongoing, are already full.
“In this particular instance, because the project is rural and in the mountains, some of the materials can be re-used locally,” he said. “The road goes through two Indian Reservations and lands owned by some private property owners. Many of the local roads are arterial and currently dirt roads. So we’re going to do two things — take some of it to a designated licensed waste area to refill an existing hole that is there and work with the Indian tribes and homeowners to place six inches of milling on their roads to be a permeable-type driving surface to decrease the dust, help with erosion, and other associated issues.”
Coffman Specialties is doing all of the major asphalt work, all of the work for the approach slabs, but is bringing in Gerdau Reinforcing to do the reinforcing (epoxy coated) rebar for the approach slabs to the bridges and J Francis Co. will be responsible for the rehabilitation of the bridge decks and replacing the joint-steel between the approach slabs and the bridge. Other subcontractors include Ferreira Construction for metal beam guard rail, and Payco Specialties for pavement markings.
The project will see Coffman have his crews work a long single shift as he anticipates that they will be able to replace one-lane mile per-day.
“Currently the lane closure chart allows us to close the lane down for 10 hours in one direction and 10 hours in the other direction,” he said, “so we’ll work the entire shift to do that. After we replace the road, we also have to temporary stripe it on the fly. We’re trying to get the state to allow us to go to a more staggered, longer shift, so we can potentially utilize a double-shift. However, we are going to try to limit this to daylight hours as we prefer safer daytime hours than night hours.”
At peak, there will be more than 30 Coffman and subcontractor personnel on site, along with 35 to 45 trucks servicing the job. A trailer that has been used by the Border Patrol is being rented as a field office, as well as a local yard to store equipment and vehicles and building materials. Vehicles also will be parked along the median to be in place for the next day’s work.
Trucks are crucial for this project and Coffman is deploying 45 double-bottomed transfer trucks for hauling the asphalt to the job site. At least 10 trucks will be used to take the millings away from the job site and 25 plus will be hauling asphalt from the plant to the job site.
“Another unique thing about this project is that Caltrans is requiring the use of a transfer vehicle — this is one of the first jobs where they’ve done that,” said Coffman, “so we have to use one in order to pave the job. We’ll have two pavers on the job — one to lay the base course, even if we have single-shifts, and another to lay the finish course down. We could probably do it with one, but in case one breaks down, we have another so that we can continue and have a contingency plan.”
The project is located 75 mi. (120.7 km) from Coffman’s main office/yard. An onsite mechanic will be on hand to do immediate repairs and scheduled maintenance. Equipment operators do their daily checks and report any problems to the foremen and the mechanic.
While the equipment and vehicles are thoroughly checked out prior to being sent to a work site, repairing them is made easier for Coffman’s eight mechanics, who are paired with a maintenance truck (placed on a Peterbuilt chassis) that combine storage for tools, spare parts, fuel and oils.
“We have two asphalt pavers, eight concrete pavers and four portable concrete plants that we operate within a 500-mile geographical radius of San Diego,” said Coffman, “so we have extensive portable equipment that we use for similar jobs like the one on I-8. Our mechanics are all linked to the home office with iPads and they have computers to check the equipment.”
While the mechanical systems of the equipment and vehicles are not monitored electronically, each piece has a GPS tracking system to help maximize productivity, including the filling of the hole with the milled road material. It also will help to track the amount of material laid on the new road and the position of the equipment.
For refueling, Coffman has a fuel truck that is bolstered by the trucks used by the mechanics.
“On this job we’ll also use a wet tap for some of the trucks and stuff where the supplier of the fuel is actually going to fuel the equipment,” said Coffman.
According to him, extensive planning is what will make this project a success.
“We work on a lot of remote projects and have done jobs that are virtually in the middle of nowhere where you don’t even have places for people to stay,” said Coffman. “So major lessons learned are that you have to pre-plan, make sure that you stage your materials appropriately, and that you track the materials you are going to utilize, as well as what you have utilized. You need to have all your spare parts and other elements to keep things operational readily available at the job site.”
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