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*Beaver Creek Br. [#wf53f22c] **1.Field of application [#n81ceea8] >The Beaver Creek bridge of I-80 crosses Beaver Creek in Clarion County, Pennsylvania. **2.Circumstances of repair [#bcb71539] >Fatigue cracks were found along the transverse connection plate end and along the web-flange fillet weld in 1984 after ten years over of service from building in the 1960's. **3.Types of structure [#mdb09437] >The structure consists of five continuous girders which are built-up members with the top flange embedded in the reinforced concrete deck, transverse cross bracing. The plan and elevation views are shown in [[figure 1>#fig1]].The transverse cross bracing is spaced at 5.8 to 7.3m([[Fig.2>#fig2]]). The transverse cross bracing is bolt connected to transverse connection plates which are fillet weld connected to the girder webs and snug fitted to the girder compression flanges. The transverse connection plates are cut short 25mm of the girder tension flanges. The girder web is of 10mm thickness A36 steel. &br; CENTER:&aname(fig1);&attachref(Beaver17.gif);&br; &br; CENTER:Fig.1 Plan and elevation views, Beaver Creek Bridge.&br; &br; CENTER:&aname(fig2);&attachref(Beaver18.gif);&br; &br; CENTER:Fig.2 Transverse cross bracing layout.&br; **4.Details of loading [#sf4abfb3] >Fluctuating loads due to vehicles live load. This resulted in large cyclic stresses at the web-flange weld toe and the transverse connection plate weld termination. **5.Description of damage [#q5a3d98e] >Fatigue cracks were found along the transverse connection plate end and along the web-flange fillet weld ([[Fig.3>#fig3]],[[Fig.4>#fig4]]). >Cause of fatigue crack was as follows: -Out-of-plane displacement which occurred in the girder web gaps. &br; &br; CENTER:&aname(fig3);&attachref(Beaver19.gif);&br; &br; CENTER:Fig.3 Fatigue cracking at the transverse connection plate locations. &br; &br; CENTER:&aname(fig4);&attachref(Beaver20.gif);&br; &br; CENTER:Fig.4 Fatigue cracks in the top web gap along the web-flange fillet weld toe and the transverse connection plate weld termination. &br; **6.Repair method applied [#eb1398b6] >Repair of parts subjected to cracking were performed by hole-drilling in the girder web 51-76mm on each sides of the transverse connection plate adjacent to the tension flange ([[Fig.5>#fig5]]). The drilled holes were located away from the located web gap stresses. &br; CENTER:&aname(fig5);&attachref(Beaver21.gif);&br; &br; CENTER:Fig.5 Recommended retrofit for cracking along the web-flange fillet weld toe and at the transverse connection plate weld termination.&br; &br; &br;
