Fatigue and Fracture Research Group
 

Tuttle Creek Restoration


Funded by the Kansas Department of Transportation (KDOT)

The Tuttle Creek Bridge is a 5,350-ft long steel structure comprised of 30 spans carrying K-16 over the Tuttle Creek Reservoir near Manhattan, KS.  The two-girder bridge was constructed in 1962, and is the only carrier of traffic over the reservoir.  Because the bridge is only composed of two steel girders, it is designated as fracture-critical, which means that a failure of either girder would likely result in the collapse of the bridge.   

Over time, the Tuttle Creek Bridge developed a large number of fatigue cracks due to distortion-induced stresses.  Because the bridge is considered fracture-critical, these cracks posed a great safety concern.  Crack prevention repairs were performed in 1986, however, subsequent inspections showed that cracks were continuing to initiate and propagate. 

The University of Kansas was retained by KDOT in 2000 to perform a study of the bridge behavior.  Since then, KU has performed a number of studies for KDOT concerning the Tuttle Creek Bridge.  Those studies have addressed:  

 Bridge over Tuttle Creek reservoir

 
  • Retrofit methods to stop new cracks from initiating,
  • Repair of existing fatigue cracks, and
  • Subsequent monitoring of the Tuttle Creek Bridge to verify and quantify improvement over previous behavior.
     

Retrofit and repair methods were determined through a comprehensive finite element study of the affected portions of the bridge.  After the KU team determined suitable retrofits for the bridge system using data obtained in the finite element study, the bridge was monitored in the field.  Performance monitoring was carried out though field instrumentation and truck-loading to obtain data concerning the behavior of the bridge under real loads.  The field investigations have shown that the repairs and retrofits were successful in decreasing the forces which were causing the numerous fatigue cracks.  To-date, KDOT has not discovered any new fatigue cracking in the Tuttle Creek Bridge.

Because the retrofits appear to be successful, the useful life of the Tuttle Creek Bridge is estimated to be over 100 years – saving the State the enormous expense of an impending replacement.  This study, in addition to other studies  performed by the KU team, have saved KDOT millions of dollars by enabling them to responsibly continue to use existing, aged bridges.