Steel bridge on roadway bridge(intersection of valve ribs and crossbeems) のバックアップ(No.1)

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Steel bridge on roadway bridge(intersection of valve ribs and crossbeems) へ行く。
- 1 (2014-01-22 (水) 15:27:57)

Steel bridge on Hanshin Expressway (welded joints between vertical stiffeners and orthotropic deck plate) †

1.Field of application †

Steel bridge of The Hanshin Expressway, Japan.

2.Circumstances of repair †

Fatigue cracks were detected on welded joints between vertical stiffeners and orthotropic deck plate in 2005 after 9 years of service.

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3.Types of structure †

The outline of the bridge structure is as follows.

Bridge length : 165.0m

Span length : 49.3+75.0m+44.6m

Structure : Box girder bridge with orthotropic deck system

Structural steel : SM490Y

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4.Details of loading †

Fluctuating loads due to highway live load.

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5.Description of damage †

Fatigue cracks were detected on welded joints between vertical stiffners and orthotropic deck plate.Type-A cracks initiated from the orthotopic deck side toe of the weld bead and propagated at a orthotropic deck. Type-B cracks initiated from the vertical stiffeners side toe of the weld bead and propagated at orthotopic deck after penetrating through the weld bead(Fig.1). .

File not found: "type-a-b.jpg" at page "Steel bridge on roadway bridge(intersection of valve ribs and crossbeems)"[ź��]

Type-A　　　　　　　　　　　　　　　　　　　　　　　　　Type-B

Fig.1 Crack location

Cause of fatigue cracks was as follows:

Localized stress concentration which resulted from the restraint of the deck plate deflection due to the wheel load.

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6.Repair method applied †

Retrofitting measures were cutting treating of semicircle at the vertical stiffeners(Fig.2).

File not found: "cutting.jpg" at page "Steel bridge on roadway bridge(intersection of valve ribs and crossbeems)"[ź��]

Fig.2 Cutting treating of semicircle

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Reference †

Yoshihiko TAKADA,Yoriko KAWAKAMI,Yuji SAKAI,Masahiro SAKANO, Study on retrofit measures in weld of vertical stiffener cutting treating of the semicircle in orthotropic steel deck, STEEL CONSTRUCTION ENGINEERING, Vol.16, No.62,2009.(In Japanese)