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/306852
T h e C o l o r a d o D e p a r t m e n t o f Transportation's (CDOT) new 4th Street Bridge in Pueblo, Colo., features twin concrete segmental bridges built utilizing balanced cantilever construction over 28 active rail tracks and the Arkansas River. Bridge construction began in December 2007 and is scheduled to be completed in early 2011. The existing seven-span 4th Street Bridge opened in 1958 and carries two lanes of traffic in each direction, linking historic downtown with the western residential neighborhoods of Pueblo. The existing bridge consists of a non- composite reinforced concrete deck on steel plate girders, which are supported on concrete multicolumn pier bents. Options to replace and repair the existing bridge were evaluated prior to design, but the condition of the aging substructure drove the decision to replace the existing bridge. profile 4TH STREET BRIDGE / PUEBLO, COLORADO BRIDGE DESIGN ENGINEER: FIGG, Denver, Colo. PRIME CONTRACTOR: Flatiron Constructors Inc.—Intermountain Division, Longmont, Colo. POST-TENSIONING CONTRACTOR: VSL, Grand Prairie, Tex. CONCRETE SUPPLIER: Transit Mix Inc., Pueblo, Colo. PIER TABLE AND TRAVELER FORMWORK: DOKA, Los Angeles, Calif. PIER FORMWORK: EFCO, Phoenix, Ariz. STEEL REINFORCEMENT: Banner Rebar, Denver, Colo. POT BEARINGS: DS Brown, North Baltimore, Ohio MODULAR EXPANSION JOINTS: Watson Bowman Acme, Amherst, N.Y. POST-TENSIONING GROUT: Sika, Lyndhurst, N.J. A record-setting concrete segmental bridge for Colorado focused on efficient construction and community involvement After evaluating several structure types, a concrete segmental solution with long, open spans and a minimal footprint proved to be the best option. Tight yard constraints and closely spaced railroad tracks eliminated conventional structure t y p e s , w h i c h re q u i re d e x p e n s i v e track closures and potential track realignments to meet current railroad clearance requirements. According to Dean Sandoval, CDOT project manager for the 4th Street Bridge replacement, "Balanced cantilever construction provided the least impact to the railroads and was the most cost effective." Using the existing track layout, a 378-ft-long main span over 23 Union Pacific Railroad (UPRR) tracks was developed, which is a record for the longest highway bridge span in the state of Colorado. Once the main-span lengths for the twin bridges were established, the side-spans were proportioned to by Karen Rowe, Colorado Department of Transportation, and John Dvorak and Steve Fultz, FIGG Pueblo's New 4th street brIDGe Bridge aesthetics selected by the Pueblo community complement the bridge theme, which blends contemporary sculpture, natural environment, and Pueblo heritage. Rendering: © FIGG. 18 | ASPIRE , Fall 2009 P R O J E C T Fourth_Street_Bridge_fall09.indd 18 9/14/09 4:16:40 PM