Explicit modeling of damping of a single-layer latticed dome with an isolation system subjected to earthquake ground motions

摘要

The non-uniformly distributed material damping in single-layer latticed domes subjected to earthquake ground motions has been ignored in engineering practice, and the structural damping of bearings and joints has been modeled at a structural level in previous studies. In this paper, an explicit method for modeling the material damping and structural damping using a finite element method is proposed. The proposed method includes important characteristics for modeling single-layer latticed domes. The steel material damping is directly taken into account using Ramberg-Osgood material model (power-law) with hysteretic damping; the structural damping at bearings is modeled based on the bearing type. The ball joints of domes tend to be simplified as nodes in the finite element method without considering the actual geometric shapes and sizes of the balls for convenience. In this paper, the energy dissipation at joints and modeling methods for damping are proposed and discussed in terms of the joint type in domes. To illustrate the proposed method for computation, a typical single-layer latticed dome with base isolation bearings subjected to six near-fault earthquake ground motions is selected as an example. The dynamic demands of this single-layer latticed dome are analyzed using the simulation technology proposed in this paper. The effects of key parameters of the dome on the damping forces, which are of interest to many practitioners, are presented and discussed. Compared with the previous modeling methods for damping, the proposed method can model the damping effects of domes with a higher fidelity, which eliminates the unrealistically high forces generated with conventional modeling methods. (C) 2015 Elsevier Ltd. All rights reserved.