Inland Empire Market Report

Rats! Rodents Relocated Before Freeway Construction Begins

 

Endangered kangaroo rats were corralled and moved to a protected habitat. The $313-million 210 freeway extension will stretch from Linden Avenue in Rialto to the connection with Route 30 in San Bernardino. Construction of the Lytle Creek bridge will be the project's chief challenge.

The 8-mi. last leg of the 210 Freeway extension project in western San Bernardino County is chugging eastward like a steady, slow-moving train, stopping here and there to pick up a few endangered species or cross a wide creek.

Construction crews working for Atkinson Construction pour concrete for the Pepper Street Bridge (photo by Paul Napolitano).

"Environmental constraints are the biggest challenge on this project," said Carole Sanders, senior resident engineer with Irvine-based Lim & Nascimento Engineering Inc., the project's construction management firm. "There is a lot of habitat that we have to maintain."

Costing $313 million, the new leg of the Foothill Freeway will stretch from Linden Avenue in Rialto to the connection with Route 30 in San Bernardino.

The project cuts through isolated portions of land inhabited by the San Bernardino kangaroo rat, an endangered species that experts say once roamed over 300,000 acres in San Bernardino and Riverside counties.

Sanders said that before construction could move through areas such as Lytle Creek in San Bernardino, the rare rat had to be captured and relocated to a new habitat about 1 mi. away.

"We created a habitat for them outside of the construction area and then relocated them there," she added.

Workers then built dense, 4-ft.-high fences and stuck them deep in the ground to keep the rodents from returning.

"They have a tendency to want to get back where they came from," said Greg Hefter, program manager with Aliso Viejo-based Fluor Corp., the project's consulting engineering firm. He said a total of 13 rats were relocated, enough to satisfy the U.S. Fish and Wildlife Service.

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Two more years of construction

Managed by a partnership between San Bernardino Associated Governments and Caltrans, the project broke ground in January and is about 35-percent complete.

Designed to help relieve congestion on Interstate 10 and on surface streets, the extension is being built by general contractor Atkinson Construction of Laguna Hills.

When finished in late 2007, SANBAG estimates that approximately 163,000 cars a day will navigate the new freeway section on eight new lanes and carpool lanes. The final leg completes a 28.2-mi. journey from La Verne to San Bernardino.

Key construction details include the widening of three existing bridges and the erection of 12 retaining walls (2,500 lin. meters), including three mechanically stabilized earth walls; nine sound walls; and a 1.5-mi. channel to provide drainage.

Rough grading has been finished. Two of the seven new bridges are done, and work is underway on the other five.

Deep columns needed for Lytle Creek bridge

The 140-ft.-long columns for the bridge spanning Lytle Creek have a diameter of 7 ft. and were drilled 115 ft. into the ground (photo by Greg Aragon).

The largest and perhaps most intriguing of these structures is the bridge over Lytle Creek, which must span 558 ft. over a sand-bottomed river and is being built on 24 massive CDIH piles.

Hefter said the wash was projected to have up to 45 ft. of erosion in the channel bottom over the 75-year life expectancy of the bridge. The columns, which are about 140-ft. long and have a diameter of 7 ft., had to be placed 115 ft. into the ground with one of the industry's largest drills and a 225-ton crane.

And to compensate for erosion, the columns had to be fully formed throughout their entire length.

"Over the years, the channel bottom is going to scour and more and more of the column will be potentially exposed in the future due to erosion," Hefter said.

The cast-in-place bridge is 157 ft. wide. When the superstructure is placed on top in the spring, it will be a free structure and not tied to the columns.

"The design is very interesting," said Mario Alarcon, Lim & Nascimento's structure representative.

"It is uncommon that we are not tying the superstructure to the substructure like you see in similar projects. This one is like a piece of wood sitting on top of some benches."

Alarcon said the reason for leaving the superstructure free and for placing the columns so deep is that a fault line runs beneath Lytle Creek. He said that this type of engineering will allow the bridge to move up to 3 ft. in each direction in case of seismic activity.

Funding for the freeway is provided in part by Measure I, the half-cent sales tax for transportation improvements in San Bernardino County, and from state and federal funds.