I-405 construction crews remove concrete from Skirball Bridge.

Anyone who has driven the Westside near the 405 Freeway has surely noticed the upswing in bridge and overpass work in recent months. Construction crews have begun demolishing portions of concrete bridges and overpasses that need to be widened as part of the I-405 Sepulveda Pass Improvements Project.

Widening is planned for 13 overpasses and three bridges as part of the 10-mile carpool lane on the northbound 405 and other improvements to be added between the I-10 and U.S. 101 Freeways scheduled to open in 2013.

One might wonder what construction crews will actually do with the broken concrete and asphalt (the project team calls it “demolition material”) that must be hauled away before all those overpasses, bridges and other structures can be widened. All that material has to go somewhere.

The answer, says Metro’s I-405 project team, is actually a win-win-win for Metro, freeway traffic and the environment.

Before I go any further, here’s a quick hint: you’ll soon be driving past it and on it.

Rather than clog the freeway with a conga line of refuse-laden trucks destined for far away storage grounds or landfills, Metro has begun crushing the concrete and asphalt from the bridges and other I-405 project demolitions at “recycling crusher” sites along the project corridor.  It is also recycling the steel rebar by sending it to recycling centers.

The crushed materials will support retaining walls along the project and form the base of new roadway when it comes time to pour the concrete for the new traffic lane.

Metro contractors are also crushing rocks from earth that is excavated along the Sepulveda Pass, where workers are carving out part of the hillside to create space needed for the new carpool lane.

Here’s a startling stat on these efforts: crushing the material onsite may save approximately 200,000 tons of demolition material from reaching local landfills.

The project team likens this amount to the weight of 4,000 blue whales at birth or the weight of an empty crude oil supertanker.

Nice.

Crusher stacks materials for later use as base fornew 405 carpool lane roadway.

Metro’s aims, of course, aren’t entirely altruistic. The agency identifies the recycling of project construction materials as a key strategy in the agency’s Sustainability Implementation Plan. But to the point, it saves the agency – and hence taxpayers – money by cutting costs associated with transporting concrete back and forth and paying the fees for dumping the materials in a landfill.

But what about the environmental concerns for crusher sites? Kiewit Infrastructure West Company (Kiewit), Metro’s main contractor for the project, has received approval from the South Coast Air Quality Management District to operate material-crushing sites within the project boundaries. The company is required to follow its dust abatement plan and meet noise requirements as it performs its crushing operations.