With an existing 1975 bridge that was demolished due to structural deficiencies, a new replacement pedestrian bridge crossing the Arkansas River is underway. The arched bridge consists of twelve 120’ steel arch spans supporting a steel deck, with a combined pre-cast and cast-in-place concrete overlay.
The deck is supported from the arch by a series of vertical steel “spandrel” plates. The only expansion joints are located at the ends of the deck, and upon completion, the spandrel plates will tend to tilt outward in warm temperatures and inward in cold temperatures. Enter Team Degenkolb.
Considering this sensitivity to temperature variations during erection, Degenkolb engineers worked with our client Kienlen Constructors, An Alberici Enterprise, to devise a method to erect each span at ambient temperatures such that when completed and at 60 degrees Fahrenheit, all 120 spandrel plates will be in a nearly vertical orientation.
As part of its erection procedure, Degenkolb designed a pair of steel tendons coupled to hydraulic jacks and connected to the ends of each arch. For each span the tendons will be tensioned using the jacks based on ambient temperature at the time of erection.
