The Bronco Arch Bridge, which is a 60-year-old structure, was extremely deteriorated from overuse, causing low sufficiency ratings. To fix the problem, the Colorado Department of Transportation (CDOT) issued a new design, a Value Engineering Redesign, with Lawrence Construction Company and Summit Engineering as part of an accelerated bridge construction initiative. Lawrence and Summit prepared a new design with extensive use of precast concrete. The structural scheme will feature a rigid frame consisting of a precast concrete superstructure and substructure with integral connections on flexible foundations.
The new structure was built on the same location as the original bridge but is shorter and has a wider deck to increase traffic capacity and accommodate four through lanes of traffic in both directions. At either end of the bridge, the substructure features fully precast concrete piers founded on drilled shafts and abutments that were constructed under the existing bridge prior to demolition. The superstructure consists of a precast, posttensioned concrete deck slab supported on eight continuous spliced precast concrete girder lines.
Precast concrete was able to enhance the structure while reducing erection time, shortening the overall schedule and lessening the effect on existing traffic. The rigid frame design of the bridge improved the structural efficiency and stiffness of the system, which allowed for greater optimization of the precast, prestressed concrete elements.
The extensive use of precast concrete elements greatly reduced the construction time and minimized the number of construction phases. Thanks to the use of precast concrete in this project, a vital urban structure was rebuilt within budget and schedule with minimal inconvenience to the citizens of Colorado.