Study on Behavior of Escalator During Earthquake

Fall accidents of escalators occurred in 2011, in an earthquake off the Pacific coast of Tohoku. The escalators where the accidents occurred was connecting the second floor to the third floor in commercial facilities of a steel frame building. In general, escalators are set on beams of buildings. Furthermore, one side or both sides of the support are not fixed to prevent damage to the escalator from the interlaminar deformation of the building. However, interlaminar deformation of the building occurred more than expected due to the earthquake. In consequence, the fall accidents occurred because the escalators came off from the beams in the buildings. After the escalator accidents, the seismic standard was revised in Japan. The interlayer displacement angle of buildings is now considered more than before. From this, the overlap allowance is longer, so the possibility of the fall accidents decreases. However, an unfixed part of the escalator may collide with a building beam due to an earthquake. Furthermore, the escalator may transform by the collision and affect their safety. In this study, the dynamic behavior of escalators with building beams during earthquakes are investigated, furthermore, the safety against the revised earthquake resistance standards are confirmed. In this paper, the analysis methods for the safety evaluation is investigated in a three meter lift escalator, which has fallen due to an earthquake. The 3/10 scale model is based on the three meter lift escalator which a top that is not fixed was created. Further, the vibration experiment with the 3/10 scale escalator model was carried out. The behavior of the 3/10 scale escalator model was confirmed during the earthquakes. Moreover the seismic response analysis was carried out with the lumped mass models. The restoring force characteristics of the escalator were modeled in two different methods. The validity of the analysis model was confirmed by comparing the analysis results with the experimental results.