Study on improvement of strength of Beam-column Joints at railway RC rigid-framed viaducts

In Japan, in order to make the city centering around the station, we are developing the underpass of the station as a commercial facility. Therefore, a structure that enlarges the column span and reduces the cross-sectional height of the beam to widen the under-elevated space is desired. However, while the amount of reinforcing bars increases, the beam-column joints become smaller, so that the reinforcing bars are overcrowded in the beam column joints. In addition, since the fixing length of the reinforcing bars is insufficient, or the strength of the beam-column joint cannot be sufficiently secured, problems such as not having a sufficient proof stress on the joint portion which should originally be stronger than the beam and column member. In this report, we developed a fixing method of reinforcing bars of column beams which improves the proof strength of beam-column joint and also simple reinforcing bars even in the case of small beam-column joint, and applied to station construction work, we report on them.