Application of new Technology for Replacement of Deteriorated Concrete Slab

Owing to the heavy traffic on the Hanshin Expressway, it is necessary to minimize the road closure period required for the replacement of deck slabs. Moreover, to prevent new replacement deck slabs from future deterioration, they have to be designed according to the current standards. Therefore, if they are formed of the same materials as the original deck slabs, the former become thicker than the latter, and it is necessary to change the vertical alignment. However, this is difficult to achieve in case of the Hanshin Expressway, as it mostly consists of continuous viaducts. In this regard, we employed a deck removal method in which the concrete on the upper flange of the steel girders of composite steel plate girder bridges was removed with high- pressure water (hydro-jet RD method). Further, ultra-high-performance fiber reinforced concrete (UHPFRC) deck slabs were used to replace the concrete deck slabs for the first time in Japan.