PSI - Issue 38

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Yuichi Shiraishi et al. / Procedia Structural Integrity 38 (2022) 588–595 Author name / Structural Integrity Procedia 00 (2021) 000 – 000

590

（単位： mm ）

although a one-side bolt for friction joint needs to do it. Furthermore, TRS can secure sealability of a trough rib [Mizogami et al. (2017)]. In the new structure (U2), the trough rib was connected to a deck plate and cross ribs by TRS. The trough rib in the new structure wasn’t connected to a deck plate and cross ribs by weld which is a weak point of fatigue. On a deck plate, two steel plates with 80mm in width were spliced by TRS. A new trough rib was welded to these steel plates. As with the existing structure, the weld penetration depth was secured over 75% of thickness of a trough rib. 2.2. Locations of strain gauges Fig. 3 shows locations of strain gauges around welded joints between trough ribs and a cross rib. Around welded joints between U1 and a cross-rib, single axis strain gauges were pasted on the trough rib, and 3-axis strain gauges were pasted on the cross rib for verifying the effect of retrofit using angles. These strain gauges were 5mm distant from weld toes. These locations of strain gauges were same when stress was measured in bridges in service [Ichinosse et al. (2019)]. Around the crossing part between U2 and a cross-rib, 3-axis strain gauges were pasted on the cross rib. These strain gauges were 5mm distant from weld toe which joined a deck plate and a cross rib. Around the crossing part between them, any welded joints weren’t existed expect its welded joints. 4 single axis strain gauges were pasted on the surface of the deck plate for detecting fatigue cracks initiated from welded joints between a deck plate and a trough rib and fracture the deck plate. Strain gauges which were pasted on the deck plate were 5mm in length. Other strain gauges which were pasted close to welded joints were 1mm in length. 2.3. Loading test procedure Loading condition is shown in Fig. 1. The specimen was loaded on three cross-sections by using rubber plates which were 200mm in length and width and 40mm in height. Loading areas A and B were set on inside welded joints between trough ribs and the deck plate. The loading area B was set on the deck plate between welded joints between trough ribs and the

756

756

756

+7%

+7%

従来構造 + 補強（ U1 ） 改良構造（ U2 ）

The existing structure (U1)

The new structure (U2)

Fig. 2. details of a connection between trough ribs and a cross rib

Fig. 3 locations of strain gauges around welded joints between trough ribs and a cross rib

Fig. 4 loading waveform under conducting fatigue test

deck plate. Loading areas A and C were decided by FEA [Matsumoto et al. (2018)]. These loading areas replicate the loading condition which cause the trough rib deforming horizontally, and fatigue cracking at welded joints between