THE CONCRETE BRIDGE MAGAZINE

SPRING 2009

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.

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The Richmond Hill Bridge in Conifer, Colo., creates a separate grade crossing a n d e n h a n c e d s a f e t y f o r n e a r b y mountain residents plus safer access to and from the adjacent fire station. It is part of a larger project to widen U.S. 285 from two to four lanes for approximately 2 miles and create a new animal crossing at the site. Goals for the project included creating a signature design and providing an attractive, cost-efficient structure to inspire later designs along this highway and elsewhere in the state. Achieving these goals required value-engineering the original plan and creating a unique approach in which precast concrete U-girders made with constant-depth bottom flanges were converted into variable-depth flanges at the site. Initial bids on the widening project as designed by the Colorado Department of Transportation (CDOT) were rejected profile RIC h Mond hIll BRIdge / CONIFER, COLORADO EnGInEER: Colorado Department of Transportation, Denver, Colo. ConCREtE PIER Consultant: HDR Inc., Denver, Colo. PRI mE ContRaCtoR: Lawrence Construction Co., Littleton, Colo. PREC astER: Plum Creek Structures, Littleton, Colo., a PCI-certified producer AwArds: Best Owner-Designed Bridge, Co-Winner, Precast/Prestressed Concrete Institute's 2008 Design Awards Constant-depth bottom flanges on precast concrete u-girders were converted to a variable depth at the site to reduce fabrication and transportation costs by Peter Montoya and Trever Wang, Colorado Department of Transportation because they exceeded the allowable maximum bid established by CDOT's cost-estimating engineers. Presented with this challenge to their design, CDOT's designers placed the entire project before an independent value- engineering team to find cost-effective alternatives and reduce the cost. An initial in-house, value-engineering effort changed the original cast-in-place, variable-depth, parabolic-girder concept to a precast concrete design with constant-depth U-girders and variable- thickness bottom flanges. This allowed the girders to resist large negative moments over the piers. As a result, the owner and engineer could save time and money. The independent value-engineering team subsequently suggested two minor deletions: eliminating a textured finish ColoraDo CreateS unique Solution For rural BriDge 26 | ASPIRE , Spring 2009 Aspire_spr09.indb 26 3/11/09 4:16:21 PM

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