Work Speeds Ahead on Replacing Century-Old Bridges With Tunnel

Utah DOT Improves Interstate System

Wed September 06, 2006 - West Edition
David H. Recht



The state of Utah is currently investing in the interstate system to better equip the state for the surface transportation needs of the 21st century.

The reconstruction of I-15, which was let in spring 2006, consisted of improvements in Weber County, (north of the I-15/I-84 junction, in the city of Riverdale, to the city of Farr West) resulting in new heavy-duty concrete pavement and a safer interstate alignment.

Roadway projects of this magnitude involve an interchange between importing fill dirt, and hauling off excess cuts throughout the right of way width. In many cases, the contractor minimizes the amount of total haul mileage by careful phasing of the job. In some cases, dirt exchanges with commercial construction projects are executed. Again, the timing of the jobs determines the earthwork cost.

Earthwork is hauled in trucks of varying capacity, ranging from incidental landscape grading, in pickup trucks, to major dirt hauling in 10-yd. trucks. Likewise, large quantities of concrete are poured in heavy-traffic conditions.

Mixer trucks have many different specifications and capabilities. For heavy construction such as the I-15 project, a fleet of Peterbilt trucks powered by a Cat 3306 diesel can be used.

Transmission is eight-speed, including a “Low-Low” configuration. The mixer can haul a maximum of 10 cu. yd., and, with a regular system of maintenance, including painting, can be used for project after project.

Additionally, the cost of construction materials has increased over a large scale in recent years. Aggregates, cement prices, and the skyrocketing cost of oil have led to large escalations in capital costs.

These factors are playing out across the country, not only in Utah, which makes efficient phasing and execution of construction all the more important for the general contractor’s profit.

The I-15 project will be carried out in varying traffic control phases.

During daytime hours, both northbound and southbound traffic will have two open lanes.

For nighttime construction, the contractor will close one additional lane in each direction. This will enable pavement operations, franchise utility relocations, and stormwater installation to occur during low frequency interstate travel at off-peak times, late at night.

Also, the project involves intersection reconfigurations at outdated approach and exit ramps. A full reconstruction of Pioneer Road, 12th Street, and 31st Street is planned, as are improvements to the 21st and 24th Street points of ingress and egress to the interstate.

These lanes were built during the original interstate system construction, and were designed for substantially less traffic, which drove at substantially slower speeds.

One of the highlights of the project is the crossing of the Weber River.

In order to maintain traffic, the existing bridge must be replaced, a new bridge must be installed, and traffic must constantly flow, which makes it necessary to demolish the bridge in halves.

For more information, visit www.udot.utah.gov/i15now.

(David H. Recht owns an Irving-based civil engineering and construction firm.) CEG