Post Retrofit Analysis of the Tuttle Creek Bridge Br. No. 16-81-2.24

Abstract

The Tuttle Creek Bridge was built in 1962. Like many older welded steel bridges, it has developed fatigue cracks. The majority of cracks were forming in the upper web-gap region. In addition, fatigue cracking was occurring along gusset plates in the structure. A retrofit was performed in 1986 to prevent further fatigue cracking. Unfortunately, the cracks propagated after the retrofit. Therefore, finite element models were created at the University of Kansas to investigate the continued fatigue cracking. The models supplied a more effective retrofit procedure that included attaching the connection stiffener to the upper flange of the girder. Two tests were planned to determine the effectiveness of the retrofit. The first field test occurred before the repair was started. Its purpose was to provide stress values in key areas for comparison after the repair. In addition, the pre-retrofit test provided information for future finite element models. In 2005, the second retrofit was completed. The purpose of this report is to present results of the post-retrofit test with data from the pre-retrofit test. Comparisons of stresses for each key area are included in the report. Details of the Tuttle Creek Bridge and testing procedure are provided. In addition, minor changes from the previous test are described.