Abstract
Elevators are essential for means of vertical transportation. In recent year, elevators to be installed in high-rise buildings are long stroke, thus the elevator ropes are longer. High-rise buildings have longer natural period than conventional buildings. As elevator ropes become longer, the natural period of the elevator ropes become longer as well, and get closer to the natural period of the building. Consequently, the elevator ropes are hooked to the equipment in hoistway when the elevator ropes vibrate by an external force, such as a strong wind and earthquake. Secondary damage such as containment of passengers and elevator service stop may occur. It has become a problem. For example, The 2011 off the Pacific coast of Tohoku Earthquake, 2215 cases such as catch and damage of elevator ropes have been reported. However, operations of elevators after earthquakes are required. Therefore, in this research, we aim to design elevator that can be operated even after the earthquakes. In this report, we examined effectiveness of elevators using intermediate transfer floors for damage reduction of ropes. In the analysis, the maximum displacement of the main rope of car side was examined when the lift stroke is divided two. The calculated results of the analysis confirmed that dividing the lift stroke reduces the response of the main rope of car side .In the probabilistic risk assessment, we examined the probability of catching of rope using the fragility curve. From the fragility curve, it was confirmed that dividing the lift stroke reduced the probability of catching of rope. Therefore, dividing the lift stroke is effective for reducing catching of rope.
