BASIC INVESTIGATION ON TORSIONAL VIBRATION OF RAILWAY DOUBLE TRACK GIRDER DURING HIGH SPEED TRAIN PASSES

Abstract

The purpose of this paper is to roughly evaluate the impact of torsional vibration on bridge design and maintenance management when a high-speed train passes through a double-track railroad girder, which has not been studied in the past. First, a standard cross-sectional model of railway double-track girders implied that a ratio of the natural frequency of the torsional mode/bending mode is about 1.2 to 1.3 times for open section concrete T girder, and 3 to 5 for closed section PC box girder or composite box type. As the results of theoretical approach, the 1^st torsional resonance may be occur in the ultra-high-speed region, while no significant resonance of the torsional mode occurs in the conventional speed range up to about 300 km/h. the dynamic response on railway structures above girder may increase due to the amplified acceleration due to torsional resonance, although the conventional design method does not evaluate the displacement response to the dangerous side without considering tortional mode.