Fundamental Study on Risk Assessment Index of Elevator Rope

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. Conventional research has confirmed that dividing lift stroke install multiple elevators is effective for reducing the response of the rope. An index, which is suitable for risk assessment, is required. In this paper, we examine the evaluation index of the fragility curve.