Steel bridge on The Metropolitan Expressway(upper end of vertical stiffener at end diaphragm) 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 The Metropolitan Expressway(upper end of vertical stiffener at end diaphragm) へ行く。
Steel bridge on The Metropolitan Expressway(upper end of vertical stiffener at end diaphragm) の差分を削除

*Steel bridge on The Metropolitan Expressway (upper end of vertical stiffener at end diaphragm) [#x11124e3]
*首都高速道路の鋼橋（垂直補剛財上端部と端ダイヤフラム）[#x11124e3]

**1.Field of application [#o4508b80]

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

>首都高速道路の鋼橋
**2.Circumstances of repair [#q57d451f]

>Many fatigue cracks were found in the upper end of vertical stiffener which was at end diaphragm.These cracks were found after more than 30 years service.
>端ダイヤフラムにおける垂直補剛材上端部に多くの疲労き裂が見つかった。これらの疲労き裂は供用開始から30年以降経過して見つかった。

**3.Types of structure [#l0437ba3]
>The outline of the bridge structure is as follows.
>橋梁の構造諸元は次のとおりである。
-Bridge length : 64.45m
-Structure : simple two Boxes girder bridge with orthotropic deck system
-thickness of deck plate : 12mm
-thickness of end diaphragm web plate : 16mm
-thickness of vertical stiffener : 19mm
-橋長　：　64.45m
-構造形式：単純鋼床版箱桁橋
-デッキプレート厚：12mm
-端ダイヤフラム厚：16mm
-垂直補剛材厚：19mm

>The cross section and clack location are shown in [[figure 1>#fig1]]. 

&br;
>断面形状は[[図.1>#fig1]]に示すとおりである. 
CENTER:&aname(fig1);&attachref(./v_e_d_cross.jpg,25%);&br;
CENTER:Fig.1 Cross section and crack location &br;
&br;
CENTER:図.1 断面形状と疲労き裂の位置 &br;
&br;

**4.Details of loading [#s6cb0d3b]
>Fluctuating loads due to highway live load.
>活荷重

**5.Description of damage [#z7d400b9]
>These cracks propagated from the boxing welded joints at the upper end of vertical stiffeners to web plates of end diaphragm([[Fig.2>#fig2]]). 
&br;
>これらの疲労き裂は垂直補剛材上端部のわまし溶接を起点とし、端ダイヤフラムへ進展している([[図.2>#fig2]]). 

CENTER:&aname(fig1);&attachref(./v_e_d_crack.jpg,25%);&br;
&br;
CENTER:Fig.2 Detail of crack 
&br;
CENTER:図.2 疲労き裂の詳細 
&br;

>Cause of fatigue cracks was as follows:&br;
>疲労き裂の原因は次のとおりである。
-Out-of-plane bending stress repetition which resulted from girder action and bridge vibration. 
-桁の動きや橋梁振動によって生じる面外方向曲げによる。


**6.Repair method applied [#l1701fd2]
>Stop holes (φ=24.5mm) were drilled at the crack tips.
>き裂先端部にストップホール(φ=24.5mm)を施工した.

//&br;
//>Permanent repair &br;

**Reference [#jfcdb670]
>Masui et al,A study on The Fatigue Crack at The End Diaphragm of Orthotropic Steel Bridge Structure with Box Girder,'''Prc.of Annual Conferenece of JSCE''',vol.61,2006.(In Japanese)
&br;