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**Sample [#sac3a3e1]
>[[Sample]] (2014-03-20 (Thu) 05:40:08)~

1.Field of application

>Steel bridge of The Metropolitan Expressway, Tokyo, Japan.&br;

2.Circumstances of repair

>Fatigue cracks were found in the coped end of the plate girder in 1978 after 14 years of service.&br;

3.Types of structure
>The outline of the bridge structure is as follows.&br;
-Span length : 31.0 m
-Structure : Simple composite plate girder bridge.
-Deck : Reinforced concrete deck ( 18.0 cm thickness )
-Structural steel : SS 41

>Elevation and cross section are shown in [[figure 1>#fig1]]. The number of the main girders which are spaced at 2.4 to 3.2 m and are seven. The main girders are deep at 1.8m and are coped at the ends. 
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&aname(fig1);&attachref(Copede1.jpg);&br;
Fig.1 Elevation and cross section &br;
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4.Details of loading
>Fluctuating loads due to highway live load.

5.Description of damage
>Fatigue cracks were found in the coped end of the main girder and the swells of the girder webs also occurred in the girder ends  due to buckling ([[Fig.2>#fig2]]).&br;
>Cause of fatigue cracks was as follows:&br;
-Concentration of stress unforeseen in design.
-Functional disorder of the movable support.
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&aname(fig2);&attachref(Copede2.jpg);&br;
Fig.2 Crack location and swell range of the girder web.&br;
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6.Repair method applied
>　Repair of parts subjected to cracking had been performed by stop hole and bolt connection as shown in [[figure 3>#fig3]]. After completion of repair, inspection indicated that fatigue crack re-initiated from the stop hole. Therefore, additional repair and strengthening were required.
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>　New plates with the rib plates were bolt connected to both sides of the girder webs ([[Fig.4>#fig4]]). This repair made the swell of the girder web reform. These new plates of 9mm thickness played the role of transmitting the load.
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&aname(fig3);&attachref(Copede3.gif);&br;
Fig.3 Primary repair.&br;
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&aname(fig4);&attachref(Copede4.gif);&br;
Fig.4 Final repair&br;
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