September 2007

Preparing for the Airbus

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By Dan Rafter

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It was no little job: Engineers with Tutor-Saliba, a civil engineering firm based in Sylmar, CA, needed 445,000 cubic feet of infiltration boxes to help construct a bioswale of more than 2.6 miles at the Los Angeles International Airport.

Photo: EcoRain
Bioswales allow for reduced excavation on the LAX project.

But to Studio City, CA–based Stormwater Solutions LLC, the job was a perfect fit. The company provided Tutor-Saliba with its EcoRain Systems infiltration boxes to build the bioswale, which is part of the $333 million South Airfield Improvement Project at the airport. David Guth of Stormwater Solutions says Tutor-Saliba opted for the infiltration boxes for a simple reason: It made sense, both economically and operationally.

“The EcoRain boxes meet and actually exceed the requirements for the job,” Guth says. “I had to show point by point that our product exceeded the specifications for the job. Without that, it wouldn’t have even been considered. It couldn’t just be good enough. It had to be better. Secondly, it costs less. Otherwise, why would they bother?”

Photo: EcoRain
Photo: EcoRain

Already rigid, the EcoRain boxes do not require geogrid above or below.

Andrew Sulewski, project engineer with Tutor-Saliba, says the bioswales were an essential part of the job, necessary to remove silt and pollution from the surface water flowing from the new runway that was built as part of the South Airfield renovation project.

“With the bioswales, we are able to minimize the amount of pipe under the taxiways,” Sulewski explains. “To get the same results without the bioswales, you’d have to excavate much more material. We wanted to reduce the amount of excavation on this project. The bioswales allow us to do that.”

The Project
Tutor-Saliba’s bioswale installation is just one part of a much larger improvement project at one of the world’s busiest airports.

The project, which started in July 2006, has already seen the late-March completion of a new runway, Runway 25 Left/7 Right, located on the south side of the airport. This was the first part of the South Airfield Improvement Project, designed to improve airfield safety by reducing the number and severity of runway incursions that occur at Los Angeles International.

A runway incursion, according to the Federal Aviation Administration, happens when an aircraft, vehicle, or object on the ground creates a collision hazard or ends up too near an aircraft taking off, landing, or intending to land. From 2000 through 2003, Los Angeles International suffered the highest number of runway incursions of any US commercial airport.

The problem hasn’t gotten any better since. In 2006, the airport had eight runway incursions. The Federal Aviation Administration classified two of them as having had the potential to result in accidents. Fortunately, no accidents did stem from the incursions.

The April opening of the new runway came eight months after demolition work started on the former Runway 25L. The new runway is located 55 feet south of its older version and boasts the same dimensions—11,095 feet long and 200 feet wide—as its predecessor.

The new runway, though, is situated so that the airport can better handle the needs of larger new aircraft, such as the heavily publicized Airbus A380 and Boeing 787 Dreamliner.

Construction began in April on the next phase of the South Airfield Improvement Project, a new center taxiway that will run parallel between Los Angeles International’s two south runways. After this, construction crews will build taxiways linking the two runways to the newly built center taxiway. Engineers estimate that it will take about 18 months to complete this phase of the project.

This phase also calls for the installation of two long bioswales, placed on both sides of the new center taxiway. A large-diameter concrete drainpipe will run up the center of the bioswales.

The bioswale, when complete, will consist of 445,000 cubic feet of EcoRain Systems infiltration boxes, which crews have been installing as double boxes. The project is the single biggest job anywhere involving underground modular systems for stormwater. Elevated inlet boxes to the center concrete drainpipe, surrounded by filtration logs, will rest every few hundred feet along the bioswales. If water ponds on the bioswales, it will enter the storm drainpipe before the runways are impacted. Crews are placing five EcoRain double boxes on each side of the drainpipe. This means that each running foot of bioswale includes 32.18 cubic feet of boxes. Each linear foot of bioswale, then, will hold 30.57 cubic feet of water.

Advantages of Boxes
Guth says Stormwater Solutions’ EcoRain boxes provided an advantage because of the makeup of the boxes themselves. Some other products would require construction crews to install geogrid below and above them to provide support. EcoRain boxes, though, are already rigid and don’t require geogrid. This saves both time and money.

“In a relatively shallow installation like this, one that’s only 3 feet deep, eliminating geogrid saved a dollar a foot in project costs,” Guth says. “That doesn’t even factor in that crews didn’t have to spend all that time installing geogrid.”

Photo: EcoRain
Each running foot of bioswale includes 32.18 cubic feet of boxes.
Photo: EcoRain
Each linear foot of bioswale will be able to hold 30.57 cubic feet of water.

The infiltration boxes are made up of panels that construction crews assemble onsite. This means that trucks shipping the product to job sites can carry more of them in fewer trips, saving on transportation costs.

“Costing less is a very important factor for us,” Guth says. “If we didn’t cost less, why should a contractor take a chance on us? If there are any problems, everyone would point to the contractor and say, ‘Why’d you go with that product?’ A contractor, then, always has to have a reason to go with a product he hasn’t tried before. The contractor’s favorite reason is cost.”

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So far, the large-scale renovation project has caused few problems at Los Angeles International. While the new Runway 25L was under construction, air traffic controllers and airlines maintained relatively normal flight schedules using the airport’s two existing northern runways and its one remaining southern runway. The airport, in fact, reported that only 0.4% of all flights into and out of Los Angeles International suffered delays because of the closure.

Part of the reason for the smooth process, unfortunately, is that the airport is handling fewer flights. According to recent statistics, Los Angeles International is currently handling about 1,800 daily flight operations. This number is 25% smaller than the 2,200 daily operations the airport saw before September 11, 2001. In 2000, the airport handled 67 million passengers. Last year, that number decreased to 61 million. This 25% reduction in flights allowed the airport to more efficiently handle the 25% reduction in runway capacity.

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