Granite Construction is building the final $114 million mainline segment of a seven-phase project designed to decrease congestion through the Carpinteria-Montecito-Santa Barbara section of U.S. 101.

The road is a major corridor for traffic flowing from Los Angeles to San Francisco.

Three phases of the $700 million project are complete, three more will be completed this year, with the final segment scheduled for completion at the end of 2028. The 11-mi. project includes adding peak-hour high-occupancy lanes in both directions, constructing 14 bridges and rebuilding stormwater management systems.

John Van Lenten is the project manager for Granite, managing 16 contracts — seven "mainline" and nine "parallel" — for the work.

"As the CMGC (construction manager/general contractor) of the project, Granite has shouldered major responsibilities," he told Construction Equipment Guide. "The project is about 75 percent complete."

Although the responsibility has been heavy, Van Lenten said the alternative contract delivery method has brought added efficiencies over the traditional design-bid-build scenario for work with Caltrans.

"Frequently, when one piece of the project is still getting permitted and funded, we have been able to get other pieces of the project moving," Van Lenten said. "When the final design elements are in place, the pieces can move forward together. I believe this approach allowed us to reduce the duration of the overall corridor by about three full years."

The Granite team has completed three segments of the work, with the Santa Barbara section now getting started. "We have just moved traffic onto the newly completed southbound lanes. This required an extended weekend Saturday/Sunday shift due to the complexity and closure requirements of the major traffic handling change."

Van Lenten calls this corridor "constrained," with space limited between established communities on the east, the Pacific Ocean on the west and a busy railroad line in between. This complicated geography brought further challenges as the team managed numerous stream crossings for the new bridges. Workers had to account for seasonal restrictions to protect the fish in some of the streams. Granite kept a biologist on call when protected species were affected.

"Another challenge occurred while demolishing some of the older bridges," he said. "In order to keep the traffic flowing during construction, we had to build some of the bridges in stages rather than all at once." Five of the bridges were precast, prestressed concrete with cast-in-place decks. Others were cast-in-place box girder bridges with parabolic arches. Significant community input was taken into consideration when designing architectural features.

"All of the bridges required significant shoring," Van Lenten said. "The water table is high, since we are near the ocean, and the work was being done near existing bridges. In addition, some of the bridges were in such rocky conditions that pile types were changed to accommodate subsurface conditions. This reduced the risk while providing the required strength."

Granite workers are using epoxy-coated rebar for some of the elements of the project. Salt-laden ocean air can have a corrosive effect on exposed metal. The coating on the rebar will help preserve these elements for decades to come.

Material Required

Much of the road sections were built on a subbase of crushed materials from demolished bridges and roads. Granite workers built the new roads with 5 in. of subbase, 3 in. of asphalt and nearly 1 ft. of concrete. The roadway required 170,000 tons of asphalt and 200,000 cu. yds. of concrete. Workers constructed 82,000 linear ft. of various types of barriers.

The Granite construction team also is building 35 retaining walls and 23 sound barriers for the project.

While working on this massive project, the Granite team also has worked on parallel projects to make it easier to access the freeway. The team constructed two roundabouts in Montecito, signalized intersections and created shared-use paths for use by walkers and cyclists.

Van Lenten is an avid cyclist and has tested the paths out himself on weekends. The stunning scenery and proximity to the ocean mean that the bike paths draw cyclists from nearby communities as well as residents.

The Granite team used a multitude of equipment for the project, including dump trucks for hauling material, excavators, bulldozers, wheel loaders, pavers and cranes.

One piece of specialty equipment, the Giken Silent Piler, used hydraulics to push sheet piles into the earth to support the highway and new bike path. This work was close to a 16-in. gas main and adjacent to railroad tracks. Granite chose to push the piles in with hydraulic pressure rather than use traditional vibratory motion to insert the piling.

Safety

Granite said it takes safety seriously — both for workers and for motorists. The company set up about 500,000 ft. of K-rail for workers to labor behind. It also installed sensors to detect when traffic was slowing down. Workers used this information to relay in real time to message boards miles ahead of the slowdown to inform motorists of impending traffic.

Already, commuters and locals are seeing the effect of the completed pieces of the massive project, including:

• Summerland improvements: undercrossings, off-ramps, bike paths updated;

• Padaro improvements: Toro Creek Bridge, Arroyo Parida Creek Bridge and the South Padaro Lane undercrossing; and

• Carpinteria improvements including the Santa Monica intersection, Santa Monica Creek Bridge, Franklin Creek Bridge, Bailard Avenue drainage, off-ramps and intersection improvements.

As the Granite team enters the home stretch of the project, it can look back at complex problems handled and a successful build.

"From an environmental perspective, we planned to protect land, air and water," Van Lenten said. "We contended with dust suppression for the air, conservation issues for the ocean and streams, and, of course, issues on land for the structures we were building."

The project has been decades in the making, and Van Lenten sees great progress.

"Motorists already are using finished parts of the road and are breathing easier," he said. "They will be facing much less congestion for years to come. No longer will they have to build time in their schedule for long delays."