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*Mashita Bridge, Japan. [#e99add8a] &size(16){1.Field of application}; > Through-type Langer bridge on the roadway bridge, Japan. < &size(16){2.Circumstances of Repair}; > Fatigue cracks were found at the joint of the vertical member and the tie girder. < &size(16){3.Types of structure }; > This bridge is the through-type Langer bridge of which arch span length is 66m [[(Fig.1)>#fig1]]. The vertical members were H-type section and were weld connected to the top flange of the tie girders.&br; &aname(fig1); CENTER:&attachref(Mashit26.gif);&br; CENTER:Fig.1 Through-type Langer bridge.&br;&br; < &size(16){4.Details of loading}; > Fluctuating loads due to wind load. < &size(16){5.Description of damage}; > Fatigue cracks occurred in the joint of the vertical member and tie girder [[(Fig.2)>#fig2]].The vertical members at the middle part of the bridge suffered the vibration due to wind of which speed was about 15 m/s. Cause of fatigue cracks is as follows. Vibration of the vertical members which was caused by Kerman's vortex. &aname(fig2); CENTER:&attachref(Mashit27.gif);&br; CENTER:&attachref(Mashit28.gif);&br; CENTER:Fig.2 Crack which occurred in the joint of the vertical member and tie girder.&br; < &size(16){6.Repair method applied}; > Emergency repair >> Fracture part were pulled back by wire rope. To prevent the vibration of the vertical members, each vertical member were connected to the adjacent members by making use of logs. << Permanent repair >> The modification of connection detail was performed so that the stress transfers smoothly to the web plate of the tie girder [[(Fig.3)>#fig3]]. The ground areas were checked by dye penetration. It was verified that no the crack tips remained. &aname(fig3); CENTER:&attachref(Mashit29.gif);&br; CENTER:Fig.3 Retrofit work.&br;
