Simplified Calculation Method for Detecting Elevator Rope Deflection during Earthquake (Considering the Distribution of Rope Tension)

Abstract

When an elevator rope for a high-rise building is forcibly excited by long-period ground motion, rope displacement becomes large even if the ground acceleration is small. Therefore, detecting the rope sway in real time is important to avoid damage during and after earthquakes. In a previous paper, when elevator cage is moving, a simplified calculation method, based on a single-degree-of-freedom (SDOF) system, for estimating rope displacement during an earthquake by using the building acceleration and ground acceleration has been presented. This simplified calculation method is applied to main rope, which resonates only once with building's sway while the elevator is moving. In the case of the main rope, the results of this simplified calculation method agree with those of the conventional finite difference method (FDM), within the 20% error margin. In this paper, a simplified calculation method is applied to compensating rope, which resonates twice with building's sway while the elevator is moving, by considering distribution of the rope tension. Finite difference analyses of rope vibration are also performed to verify the validity of the simplified calculation method. The results of this simplified calculation method agree with those of the conventional finite difference method, within the +20%,-30% error margin.