既詏鋼鉄道橋の合成構造化によるリニューアル工法の提案

摘要

鋼鉄道橋は明治時代から数多く架設され，半数以上が60年の供用を超えるなど，老朽化した鋼鉄道橋が増加している。多数の既設鋼鉄道橋は今でも十分に役目を果たしているが，腐食による耐荷力の低下や疲労によるき裂の発生が課題となっている。また，一部では列車通過時の騒音の発生なども指摘されている。%More than a half of existing railway steel bridges in Japan have been in service for more than sixty years. Some of the aged bridges have various severe problems including corrosion, fatigue and noise. In this study, we proposed a method of structural improvement of the existing railway steel bridges by composing with concrete slabs. Using this method, we can improve the load-carrying capacity of the bridges, extend the service life, and reduce the noise. We carried out a series of fundamental studies to verify the adaptability of the proposed method. Finally, we proposed a method of composition, which applicable in a tight time schedule, and found by loading tests that the girder-slab connection has adequate strength for composition of existing girders.