Nobody likes to be behind a bus for very long.
With plans for the Canoga Avenue Metro Orange Line bus station in the city of Los Angeles well under way, officials did not want needed work on the adjoining road to take a drop on the priority list. So, using the benefits of recycling and the continued pavement-preservation enthusiasm coming out of Mayor Antonio Villaraigosa’s office, the two projects ran one right after the other to provide commuters a curb-to-curb upgrade on one of L.A.’s busiest streets.
Dealing with an accelerated schedule under heavy traffic—work on the 3.15-mile stretch was completed in just 12 days—and handing Villaraigosa a busload of major savings (more than $2 million) were two major reasons why for the second year in a row, the region was celebrating a ROADS & BRIDGES/Asphalt Recycling and Reclaiming Association Recycling Award, this time in the cold planing category. Last year, Los Angeles was honored in the cold in-place (CIR) category for work done on its entire pavement-preservation program for the year, which included 18 miles of CIR.
“We are coordinating our efforts with all the other city and state agencies to provide the residents and customers with the highest level of service,” Nazario Sauceda, director of the Bureau of Street Services (BSS), told ROADS & BRIDGES. “In this case we had a nice great station right there, but the moment you left the station the condition of the street was less than optimum. We are bringing this holistic approach to everything we do from this point on.
“That is what made this project very unique. Numerous agencies worked together to obtain a common objective.”
“Our normal goal is to resurface streets like Canago Avenue based on MicroPAVER analysis when funding is available and there are no utility holds,” Keith Mozee, the division manager of the Resurfacing and Reconstruction Division of BSS, told ROADS & BRIDGES. “We had the project scheduled a few years back; however, the Metro Orange Line project was in progress so we patiently put our resurfacing project on hold. Elected officials and project managers got together and realized that a collaborative effort would be a win-win situation; that is, a brand new Metro Orange Line station and a newly resurfaced Canoga Avenue.”
Villaraigosa’s approach is working for the BSS. Before he was sworn in, L.A.’s pavement-preservation efforts were receiving approximately an average of $50 million a year. For the past six years the average annual budget for pavement preservation has been in the neighborhood of $100 million, and the last two years it has been $105 million. The level of funding is expected to remain consistent in FY 2013. The end goal is to improve the city’s pavement condition index (PCI) from its current grade of 62. The fact that the number has not dropped over the last few years is a major victory. During the current FY 2012-13 campaign, the BSS is in the process of completing 100 miles of crack sealing, 455 miles of slurry sealing and 245 miles of resurfacing.
“Six years ago we were at 62 and declining every year, and the additional funding secured that the average PCI for the network was going to remain static,” said Sauceda.
Almost 70 years ago, certain segments of Canoga Avenue between Prairie Street and Victory Boulevard carried a perfect score. While maintenance was performed throughout the years, the street had not been resurfaced until the BSS came through with its award-winning project in April 2012.
“Canoga Avenue was one of those streets that was in ‘poor’ condition and, therefore, it was strategically neglected simply because our strategy right now is to preserve as many streets as possible in a grade condition of ‘fair’ or above,” said Sauceda.
Despite the decades of static activity on the road, Mozee said the base was in pretty good condition, which led to crews only needing to mill off 11?2 to 2 in. However, the time constraint had them grinding in tandem. A Wirtgen W1900, W2000 and W2100 were all used on the job. Mini profilers—a Wirtgen W500 and W50—also were on the scene.
“Some areas we were able to cold plane at the wearing surface, where we had minimal to no pavement distress on relatively flat ground,” said Mozee. “In other areas we had to completely cut the street at full width.”
The BSS chose to handle the project in long stretches of city blocks—six segments in all. Machines and personnel would focus on one area at a time, allowing traffic to move around the work zone relatively easily. One lane of traffic was open at all times.
“We had to put up message boards to detour traffic and at the same time had to coordinate with our two asphalt plants and one vendor plant to deliver the material,” said Mozee. “We just kept moving along in segments throughout the project.”
Crews were most productive on the weekend. According to Mozee, on one Saturday they were able to pave 1.2 miles of road using 6,000 tons of asphalt.
“We would pave on Saturday, complete it after 3 or 4 in the afternoon and open the road up completely, and the DOT would come in and stripe it right after us,” said Mozee.
Once the existing asphalt pavement was milled, trucks delivered the material to the asphalt plant site 14 miles away. Two municipal plants—a Stan Steel 5,000-lb batch plant built in 1947 and a Madsen 5,000-lb batch plant built in 1953—were used. In 1998, both plants were upgraded with CMI silo load-out systems and new high air efficiency, low-NOx Hauck burners and had the capacity to utilize 20% reclaimed asphalt pavement (RAP). A third plant, an Astec Double Barrel drum, also came into play and could work in 50% RAP. Material would be sized according to the asphalt mix design and be ready to place the following day. The roundtrip truck haul took about one hour. The mix contained a PG 64-10 asphalt binder and 1?2-in. to 3?8-in. aggregate along with sand. It also called for 2-4% air voids.
Two pavers working side by side—a Roadtec RP 195 and Caterpillar AP1050—worked the hot-mix asphalt at the site. Mozee said the mix directly behind the paver was 285-300°F, and the compaction train consisted of two steel double-drum rollers and a rubber-tire roller per paver. The two double-drums served as the breakdown and intermediate roller, with the rubber-tire handling finishing work. The goal was to achieve 95% density, and as the rollers would compact the pavement, workers armed with nuclear density gauges would mark the density on the mat. That way if a spot was only at 92% crews would roll it until it reached the right density.
“[Working in tandem] produces efficiency in terms of cost,” said Sauceda. “When you pave in tandem you don’t need the rakers and workers leveling the two different passes. You basically roll it and you don’t need to have that extra body.
“You benefit by not having a lot of people . . . you maximize your crew size.”
Reducing the work force was just a small part of what went into the more than $2 million worth of savings on the Canoga Avenue project.
“Using conventional methods may end up costing us $600,000 a mile for reconstruction,” added Sauceda. “These kinds of savings are utilized to pave more streets. We can do more maintenance blankets and more of the minor resurfacing, so at the end of the year, depending on the savings, we may end up doing an additional 15-20 miles of street work.”
And any amount of savings on the resurfacing budget goes a long way for the city of Los Angeles, which has the largest road networks in the nation.
“We can go around planet Earth with our streets, and we need to maximize every single dollar that we get, and the only way to stretch this money is by recycling, reclaiming and reusing. A lot of cities will see what we are doing and try to duplicate. If we share our successes, all of the other cities in the nation become better cities and at the end of the day the economy is improving.” R&B