• Journal of the Korea institute for structural maintenance and inspection
• /
• v.13 no.2 s.54
• /
• pp.122-128
• /
• 2009

This study is to improve constructability of LB-DECK construction in site such as inconvenience of main and distribution bars in arrangements LB-DECK Panel which is work is applied to many bridges these days as a permanent formwork. So, the constructability is improved by changing the method of allocation of main reinforcing bar and distribution bar which is reviewed for improving efficiency of design and construction process among the suggested methods. The crack shapes, deflections, and strains under static load of the improvement of LB-DECK Panel are compared and analyzed to former LB-DECK Panel. As a result, 13% of strength compared to before the improvement of LB-DECK Panel, and 10% of strength is increased in the case of slab.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.25 no.6
• /
• pp.245-253
• /
• 2021

RC slab bridges account for the largest portion of deteriorated bridges in Korea. However, most RC slabs are not included in the first and second classes of bridges, which are subject to bridge safety management and maintenance. The highest damaged components in highway bridges are the subsidiary facilities including expansion joints and bearings. In particular, leakage through expansion joints causes deterioration and cracks of concrete and exposure of reinforced bars. Therefore, this study analyzed the effect of adhesion damage at expansion joints on the response of the deck in RC slab bridges. When the spacing between the expansion joints at both ends was closely adhered, cracks occurred in the concrete at both ends of the deck due to the resistance rigidity at the expansion joints. Based on the response results, the correlation analysis between displacements in the longitudinal direction of the expansion joint and concrete stress at both ends of the deck for each damage scenario was performed to investigate the effect of the occurrence of damage on the bridge behavior. When expansion joint devices at both sides were damaged, the correlation between displacement and stress showed a low correlation of 0.18 when the vehicles proceeded along all the lanes. Compared with those in the intact state, the deflections of the deck in the damaged case at both sides showed a low correlation of 0.34 to 0.53 while the vehicle passed and 0.17 to 0.43 after the vehicle passed. This means that the occurrence of cracks in the ends of concrete changed the behavior of the deck. Therefore, data-deriven damage detection could be developed to manage the damage to expansion joints that cause damage and deterioration of the deck.

• Journal of the Korea Concrete Institute
• /
• v.26 no.3
• /
• pp.385-392
• /
• 2014

Reshoring makes slab deflect and support its own weight. The construction loads on the slabs in lower levels decrease using the reshoring. Simplified analysis proposed by ACI 347.2R-05 showed that if the reshoring is applied, construction loads on slabs and shores, and quantities of forms and shores decreased by 40%, 23%, 40%, and 50%, respectively. Shores' loads were comparatively measured on site. The measured reshore load was half of the load before removing the shores and was also lower than the measured shore load by 35%. To verify the safety of the reshoring, deflections of beams and strains of beam longitudinal bars were also measured. The maximum deflection was only L/5000 and the maximum bar strain was only 3.6% of the yield strain. Consequently, reshoring neither cause problems on the safety nor serviceability. In addition, the beam load was expected from the measured shores' loads and it coincides well with the predicted value by the simplified analysis of ACI 347.2R-05.