T-type steel pier on Hanshin Expressway の変更点

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T-type steel pier on Hanshin Expressway へ行く。
T-type steel pier on Hanshin Expressway の差分を削除
*T-type steel pier on Hanshin Expressway [#q3d72226]

**1.Field of application [#x5fca88e]

>Steel pier at the Kobe-Nishinomiya line of Hanshin Expressway, Japan.&br;

**2.Circumstances of Repair [#b482ee57]

>Fatigue cracks were found in the weld joints, which connected the transverse beam flanges to the column flanges, in Sep. 1982.

**3.Types of structure [#ve886fa0]

>Detail of the T-type steel pier is shown in [[figure 1>#fig1]],[[2>#fig2]]. The transverse beam flanges were continuous and had penetrated the column. The column flanges were groove weld connected to the transverse beam flanges at the pier corners. The structural steel at the pier corners was SM 58.&br;
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CENTER:Fig.1 Plan of the T-type steel pier.&br;
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CENTER:Fig.2 Cross section of the T-type steel pier. 
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**4.Details of loading [#h1d6706d]
>Fluctuating loads due to highway live load. 

**5.Description of damage [#x19d658b]
>Fatigue cracks were found in the groove welds which connected the transverse beam flanges to the column flanges ([[Fig.3>#fig3]],[[4>#fig4]]). The longest crack length was 74mm at the detection.
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>Causes of fatigue cracks were as follows:
-Weld defect which had been included at the fabrication.
-Large cyclic stress due to live load.
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CENTER:Fig.3 Crack location.&br;
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CENTER:Fig.4 Crack of the pier corner.&br;
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**6.Repair method applied [#w32c31bd]

>In order to release the restrained stress, a part of the corner plates at the diaphragm locations was removed ([[Fig.4>#fig4]]).  Removal area was sealed by new plates, 250 by 300 by 2mm, in order to prevent corrosion ([[Fig.5>#fig5]]). 



>For the cracks which propagated into the girder bottom flanges, repair was performed by gouging, grinding and re-over welding ([[Fig.6>#fig6]]). 



>As there were space restrictions, strengthening was performed by plate connection ([[Fig.5>#fig5]],[[6>#fig6]]). These trapezoid-like plates were weld connected to the transverse beam flanges and column flanges. After the completion of this connection, repair of parts subjected to cracking was performed by gouging and re-welding.&br;

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CENTER:&aname(fig4);&attachref(Hanko64.jpg);&br;

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CENTER:Fig.4 Removal of the corner plate.&br;

CENTER:Fig.5 Repair method.&br;

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CENTER:&aname(fig5);&attachref(Hanko65.jpg);&br;

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CENTER:Fig.5 Sealing by a new plate.&br;

CENTER:Fig.6 Complete view.&br;

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CENTER:Fig.6 Gouging and re-welding of the crack at the girder bottom flange connection.&br;

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