1986 年 1986 巻 374 号 p. 329-337
To accommodate for the increase of traffic volume on load way bridges, side way bridges have been constructed in parallel with old bridges. Most bridges of this type have parallel beams connected by cross beams and comparatively large L/B ratio. Side way bridges of this type have the hazard of overall buckling at the erection stage. In order to accommodate this hazard, the following investigations and studies are carried out. First, the design data of existing side way bridges are surveyed. Next, simplified formulas for overall buckling strength are derived and the required stiffness γ is proposed. And, parallel beams under one or two equal concentrated loads are tested to investigate the ultimate load behavior. The value of γ is examined by experiments. The design recommendations are lastly proposed as a results of study.