Presentations

A sliding mode control is one of control methods with superior robustness against structural parameter change and uncertainty of a model. However, a sliding mode control requires multiple control parameters and a design method of these parameters has not been established. In this study, we propose a design procedure to determine the control parameters so as to minimize the damage probability in a certain service period of a building. A semi-actively controlled base-isolated building is studied and the damage probability based on the proposed design procedure is compared with that based on a conventional procedure that determines parameters to minimize the response under design input ground motion with a certain level of intensity.

Many researchers have investigated the vibration characteristics of mid-story isolated buildings. However, a formula to estimate their maximum responses has still room for improvement. A complex complete quadratic combination method is reformed using mode-dependent peak factors. The response of a mid-story isolated building model under white noise ground motion is analyzed and it is confirmed that the reformed formula gives slightly larger, safer-side estimates in most cases.

Finite element analysis is carried out for simultaneously investigating global displacement and local stress responses of laminated rubber bearings under earthquake excitation. Natural rubber bearings are attached at the base of a building frame. The frame members as well as the rubber bearings are discretized into hexahedral finite elements with more than 3 million degrees of freedom. It is shown that the incompressible and hardening properties of natural rubber can be accurately simulated, and the non-uniform deformation and stress distribution of rubber bearings under static and dynamic loads are successfully evaluated through a finite element analysis.