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*Steel bridge on Hanshin Expressway (at web gusset) [#mf2cef3e] **1.Field of application [#k226982d] >Steel bridge on Hanshin Expressway ,Kobe, Japan.&br; **2.Circumstances of Repair [#x4bbb18f] >Fatigue cracks were found in the weld of the gusset plates at the end vertical stiffener locations with the girder webs in Jun. 1983 after 13 years of service.&br; **3.Types of structure [#mf3ef301] >The bridge is composite simple I-section girder bridge. The framing plan is shown in [[figure 1>#fig1]]. The end vertical stiffeners and gusset plates were fillet weld connected to the girder web ([[Fig.2>#fig2]]). The lateral bracings were bolt connected to the gusset plates ([[Fig.2>#fig2]])&br; &br; &br; CENTER:&aname(fig1);&attachref(Hnako412.jpg);&br; &br; CENTER:Fig.1 Framing plan.&br; &br; &br; CENTER:&aname(fig2);&attachref(Hnako413.jpg);&br; &br; CENTER:Fig.2 Detail of end vertical stiffener and the web gusset.&br; &br; &br; **4.Details of loading [#oda45300] >Fluctuating loads due to highway live load. **5.Description of damage [#gb71ff0b] >Fatigue cracks were found along the fillet weld beads between the girder web and the gusset plate and between the end vertical stiffeners and the girder webs ([[Fig.2>#fig2]],[[3>#fig3]]). &br; &br; >Cause of fatigue cracks was as follows: -Support subsidence and differential displacement between the girders. &br; &br; CENTER:&aname(fig3);&attachref(Hnako414.jpg);&br; &br; CENTER:Fig.3 Crack along the weld bead of the end vertical stiffener and the gusset plate.&br; &br; &br; **6.Repair method applied [#we1569fe] >Analysis recommended that repair would be performed by bolt splicing as shown in [[figure 4>#fig4>>. >Analysis recommended that repair would be performed by bolt splicing as shown in [[figure 4>#fig4]]. &br; &br; CENTER:&aname(fig4);&attachref(Hnako415.jpg);&br; &br; CENTER:Fig.4 Recommended strengthening method.&br; &br; &br;
