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UDOT using faster, cheaper technique in bridge building on I-84

Published: Tuesday, July 2 2013 3:44 p.m. MDT

UDOT crews continue work on an I-84 bridge near Echo Reservoir Tuesday, July 2, 2013. Geosynthetic rain forest soil was used on the project.

Jeffrey D. Allred, Deseret News

ECHO, Summit County — The Utah Department of Transportation is using an innovative method in bridge building to replace an I-84 overpass bridge near Echo Junction.

The geosynthetic reinforcement, soil-integrated bridge system uses tons of soil and will save taxpayers time and money. UDOT is the first in the country to use the reinforced soil technique at the abutment of an interstate bridge.

"Basically what we are doing here is just building a bridge abutment out of soil and reinforcement instead of concrete," said Tim Rose, UDOT Region 2 deputy director.

Typically, massive steel pylons driven into the ground surrounded by concrete form the bridge abutment.

At Echo Junction, crews are building the footing for a 58-foot-wide span of multiple layers of compressed dirt separated by a tarp-like fabric. The abutment is done in three steps: first, laying the block; second, placing and compacting the backfill; and third, laying a sheet of the geosynthetic reinforcement. The process is repeated to the specified height of the bridge abutment.

"Layer upon layer upon layer, all held together by the geosynthetic and the gravity," Rose said.

UDOT officials said the technique will save about $200,000 on the project's $3.2 million price tag because concrete is more expensive and takes 28 days to cure.

Dozens of geosynthetic reinforcement, non-interstate bridges have been built for 30 percent to 60 percent less than traditional bridges because fewer materials are used, construction is faster and less equipment is needed, according to the Federal Highway Administration.

"The real advantage here is ease of construction and quickness of construction," Rose said.

There is also no staging of equipment or material delivery to get in the way of traffic, construction can be done in any type of weather, and only a small crew is needed, he said.

Only one temporary closure on the interstate will take place sometime next month when builders slide the bridge deck into place when the abutment is finished.

"We're in here and out of here," Rose said. "(It's) better for the traveling public because the construction time frame is shortened."

The project also requires less maintenance because it is not affected by weather changes, has fewer parts and has a jointless bridge.

Email: jboal@deseretnews.com

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