Steel bridge on roadway bridge (at coped end) の変更点

追加された行はこの色です。
削除された行はこの色です。
Steel bridge on roadway bridge (at coped end) へ行く。
Steel bridge on roadway bridge (at coped end) の差分を削除
*Steel bridge on roadway bridge (at coped end) [#u38ec4a0]

**1.Field of application [#v2c8b50f]

>鋼橋、首都高速道路,東京, Japan.&br;

**2.損傷状況 [#gd0b4d9a]

>桁端切り欠き部に疲労亀裂が見つかった。 in 1978 after 14 years of service.&br;
CENTER:&aname(fig1);&attachref(ScreenHunter_04 Jul. 04 10.37.jpg);&br;
CENTER:Fig.1 Elevation and cross section &br;
CENTER:&aname(fig1);&attachref(./ScreenHunter_04 Jul. 04 10.37.jpg,50%);&br;
CENTER:Fig.1 最近の損傷報告写真 &br;

**3.Types of structure [#t777b1cc]
>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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CENTER:&aname(fig1);&attachref(Copede1.jpg);&br;
CENTER:Fig.1 Elevation and cross section &br;
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**4.Details of loading [#r9adbfba]
>Fluctuating loads due to highway live load.

**5.Description of damage [#t9ef3387]
>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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CENTER:&aname(fig2);&attachref(Copede2.jpg);&br;
CENTER:Fig.2 Crack location and swell range of the girder web.&br;
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**6.Repair method applied [#wd8df069]
>　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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CENTER:&aname(fig3);&attachref(Copede3.gif);&br;
CENTER:Fig.3 Primary repair.&br;
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CENTER:&aname(fig4);&attachref(Copede4.gif);&br;
CENTER:Fig.4 Final repair&br;
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