Steel bridge on Hanshin Expressway (at bracket end) の変更点

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削除された行はこの色です。
Steel bridge on Hanshin Expressway (at bracket end) へ行く。
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*Steel bridge on Hanshin Expressway (at bracket end) [#h2f2c3af]

**1.Field of application [#x17e0a99]

>Steel bridge on Hanshin Expressway ,Japan.&br;

**2.Circumstances of Repair [#c9f6dd81]

>Fatigue crack was found in the interior vertical stiffener end at the bracket connection which supported the sign pole.&br;

**3.Types of structure [#rb5b64ff]
>The bridge is simple box girder bridge. The cross section is shown in [[figure 1>#fig1]]. The brackets which supported the sign poles were bolt connected to the box girder webs ([[Fig.2>#fig2]],[[3>#fig3]]). &br;
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CENTER:&aname(fig1);&attachref(Hanko116.jpg);&br;
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CENTER:Fig.1 Cross section.&br;
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CENTER:&aname(fig2);&attachref(Hanko117.jpg);&br;
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CENTER:Fig.2 Cantilever bracket which supports a sign pole.&br;
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CENTER:&aname(fig3);&attachref(Hanko118.jpg);&br;
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CENTER:Fig.3 Cantilever bracket which are connected to the box girder web.&br;
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**4.Details of loading [#sca7fb6b]
>Fluctuating loads due to highway live load. 

**5.Description of damage [#x537c5ef]
>Fatigue crack was found in the interior vertical stiffener end and at the bracket connection with the box girder web ([[Fig.4>#fig4]]). The crack originated from the interior vertical stiffener end and was branched in three directions ([[Fig.5>#fig5]],[[6>#fig6]]). The interior vertical stiffeners were not fillet weld connected to the box girder tension flanges.&br;
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>Cause of fatigue cracks was thought as follows:
-Vibration due to the vehicle pass and wind.

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CENTER:&aname(fig4);&attachref(Hanko119.jpg);&br;
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CENTER:Fig.4 Crack location.&br;
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CENTER:Fig.5 Crack of the vertical stiffener end.&br;
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CENTER:&aname(fig6);&attachref(Hanko121.jpg);&br;
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CENTER:Fig.6 Girder exterior view of the crack.&br;
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**6.Repair method applied [#p3f3f1f4]
>Repair was performed as follows. 

>The box girder web of parts subjected to cracking was removed ([[Fig.7>#fig7]]) and the plates were bolt connected from both sides of the box girder web ([[Fig.8>#fig8]],[[9>#fig9]]). The interior of the box girder was reinforced as shown in [[figure 10>#fig10]]. 






CENTER:&aname(fig4);&attachref(Gerber27.jpg);&br;

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CENTER:Fig.4 Emergency repair.&br;

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CENTER:&aname(fig7);&attachref(Hanko122.jpg);&br;

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CENTER:&aname(fig5);&attachref(Gerber28.jpg);&br;

CENTER:Fig.7 Removal of the box girder web.&br;

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CENTER:Fig.5 Range of the full penetration weld.&br;

CENTER:&aname(fig8);&attachref(Hanko123.jpg);&br;

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CENTER:&aname(fig6);&attachref(Gerber29.jpg);&br;

CENTER:Fig.8 Strengthening of the bracket location.&br;

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CENTER:Fig.6 Repair weld (Full penetration weld.)&br;

CENTER:&aname(fig9);&attachref(Hanko124.jpg);&br;

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CENTER:&aname(fig7);&attachref(Gerber30.jpg);&br;

CENTER:Fig.9 Bolt splice.&br;

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CENTER:Fig.7 Permanent repair.&br;

CENTER:&aname(fig10);&attachref(Hanko125.jpg);&br;

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CENTER:Fig.10 Interior view of the internal strengthening.&br;

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