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/297006
The I-25 Bridge over the South Platte River has been a Denver landmark structure since its initial construction in 1951. The steel arches, supporting the bridge superstructure, became known as the Bronco Arches after the Denver Broncos began playing football in the adjacent Mile High Stadium in 1960. To d a y t h e b r i d g e c a r r i e s o v e r 2 0 0 , 0 0 0 v e h i c l e s p e r d a y. A f t e r many years of service the bridge deck, superstructure, and supporting arches became seriously deteriorated resulting in the bridge having one of the lowest sufficiency ratings in Colorado. A new replacement bridge, designed b y t h e C o l o r a d o D e p a r t m e n t o f Transportation (CDOT), was bid in March 2011. The new bridge is 371 ft long and 197 ft wide to accommodate four through lanes of traffic in each d i re c t i o n a s w e l l a s a c c e l e r a t i o n lanes and on and off ramps. The superstructure consists of three spans with eight parallel girder lines with skewed abutments at each end. Value Engineering Proposal The contractor requested that CDOT consider a number of value-engineering proposals that would enhance the design of the bridge, reduce the number of stages of construction, shorten the schedule, and greatly reduce the impact on existing traffic. CDOT recognized that the value- e n g i n e e r i n g p ro p o s a l s s u g g e s t e d by the contractor would result in less disruption and a shorter schedule and allowed them to proceed. Because the project was bid prior to performing any preliminary value engineering, the designs had to be accomplished within the overall project construction schedule to avoid delays. To accomplish this, a design schedule was established with priorities driven by the construction schedule. profile Bronco Arch Bridge / Denver, Colo. BRIDGE DESIGN AND CONSTRUCTION ENGINEER: Summit engineering Group Inc., littleton, Colo. PRImE CONTRACTOR: lawrence Construction Co., littleton, Colo. PRECASTER: Plum Creek Precast, littleton, Colo., a PCI-certified producer POST-TENSIONING CONTRACTOR: vSl, Denver, Colo. The new Bronco Arch Bridge spans the South Platte River near Mile High Stadium in Denver, Colo. All Photos: Summit Engineering Group Inc. by Gregg A. Reese, Summit Engineering Group Inc. Design and construction of the replacement for the I-25 Bridge over the South Platte River The Bronco Arch Bridge 22 | ASPIre , Summer 2013 P R O J E C T Bronco_Sum13.indd 22 7/1/13 8:21 AM