The 18th Street Bridge over the Kansas River is one of the few remaining deck truss bridges on the state highway system. Built in 1959, the bridge has undergone numerous rehabilitations over its more than 60-year life. In 2017, an inspection of the 18th Street Bridge revealed some corrosion and cracking which needed to be fixed immediately and led to the eight-month closure. During the closure, nearly all areas of the bridge structure were addressed including replacing and repairing the diagonal supports and bracing members of the bridge and repairing the bottom chord of the bridge. The repairs made to the bridge will extend the life of the bridge, but the bridge will eventually need to be replaced. The bridge is nearing the end of its service life and any further rehabilitation beyond the repairs conducted in 2018 can no longer cost-effectively maintain this structure.
In 2019, KDOT completed a study that evaluated alternatives to identify a Preferred Alternative to the replace the bridge for the long-term. The study team developed bridge alternatives with the key goals being to maintain the river crossing and improve safety for travelers through the 18th Street Corridor. Multiple factors such as safety, traffic, impacts to the river and floodplain, aesthetics, public needs and opinions and length of construction were considered before recommending a Preferred Alternative.
Goals of the study included:
At the end of the study process, outlined below, and after a review of several alternatives, the On-Alignment Alternative was identified as the Preferred Draft Alternative. It is the most feasible option based on key factors and how well it enhances safety for all travelers through the 18th Street Corridor.
This graphic shows the study process that the Project Team used to develop a Preferred Alternative. A range of initial alternatives were developed to address the goals of the project. Each of the alternatives were compared and evaluated using engineering factors. The alternatives that best meet the goals of the study were carried forward for additional screening and evaluation to determine the Preferred Alternative.
The images below provide details about the current conditions of the bridge, traffic and surround area of the project location.
The bridge is currently four 12-foot lanes with narrow shoulders measuring two to three feet wide.
In the summer of 2017, a bridge inspection revealed the bridge was in deteriorating condition and in need of repairs. While the bridge was never considered unsafe, it was important to address existing corrosion and prevent further deterioration. Repair plans were developed and the bridge was closed to traffic in April of 2018. Work included significant repairs to the existing steel truss.
Repairs were completed and the bridge reopened to traffic in December of 2018. It is estimated that the repairs will extend the service life of the bridge approximately 10 years, barring any other condition issues that may arise.
Analysis of the anticipated future traffic determined that the existing roadway has capacity to safely and efficiently carry the current and projected traffic volumes on the 18th Street bridge.
KDOT Project No. 69-105 KA-4881-02