ASPIRE is a quarterly magazine published by PCI in cooperation with the associations of the National Concrete Bridge Council. The editorial content focuses on the latest technology and key issues in the Concrete Bridge Industry.
Issue link: http://www.aspiremagazinebyengineers.com/i/306189
Just outside the tiny community of Echo, in Summit County, Utah, thousands of motorists drive by on I-80 every day. In this area, I-80 is a smooth, easy route—a portion of one of the longest interstate highways in the country carrying people and products coast-to-coast for 2900 miles. Two deteriorating bridges on I-80 in this area threatened to shut down this important corridor as the Utah Department of Transportation (UDOT) needed to replace the structures. The agency estimated that any disruption to I-80 would detour the high volume of interstate truck traffic for 90 miles. U D O T i s re c o g n i z e d a s a l e a d e r i n i n n o v a t i v e a c c e l e r a t e d b r i d g e construction (ABC). They challenged the consulting and construction industry to find a way to minimize impact to the traveling public as part of the replacement of the I-80 bridges over Echo Dam Road. The agency stipulated that the design-build team must remove existing bridges and approach ramps and construct new bridges within 135 calendar days after the notice to proceed. Additionally, the closure of I-80 at Echo Dam Road was limited to 16 hours. To receive the full incentive, the road needed to be open to traffic in less than 11 hours. The contract also stipulated incentive/ disincentive pay for every 15 minutes that I-80 was opened or closed as measured against the allowable time window. The design-build (D-B) contract was awarded in April 2009. The team then developed the first project in the United States to move a bridge span into place, including the approach slabs, in just a matter of hours using hydraulic rams and slide rails. This resulted in another new first for UDOT and their innovative methods for ABC, and for a cost of approximately 60% of the state's estimate. Design basics The original three-span, I-80 twin bridges over Echo Dam Road were approximately 40 ft wide and 101 ft long including fill slopes under the approach spans that rested on stub abutments. The span lengths were 30.5, 44, and 26.5 ft. The new twin bridges are each 44 ft 10 in. wide with a single 80-ft-long main span and 25-ft-long approach slabs at either end. The approach slabs are designed to span their full length to allow for bridge settlement at the abutments. After reaching their final location, flowable fill was used beneath the approach slabs. There is a special joint between the deck and approach s l a b s t h a t a l l o w s ro t a t i o n i f t h e approach slabs settle. To meet the tight timeline and vertical clearance requirements, the D-B team opted to use economical, single-span profile I-80 B RIDGES Ov ER ECHO DAM ROAD / ECHO, UTAH br IDgE DESIgN ENgINEEr: Michael Baker Jr. Inc., Midvale, Utah prIME CoNTrACTor: Ralph L. Wadsworth Construction Company, Draper, Utah prECASTEr: EnCon Utah LLC, Tooele, Utah, a PCI-certified producer CoNCrETE SuppLIEr: Geneva Concrete, Park City, Utah by Hugh Boyle, Michael Baker Jr. Inc. A Sliding Scale The I-80 BrIdges over echo dam road New I-80 Bridge over Echo Dam Road in place and complete. 30 | ASPIRE , Fall 2011 Book_Fall11.indb 30 9/29/11 11:59 AM