Precise integration strategy for aseismic LQG control of structures

Although LQG regulators have been used in many engineering fields, the relevant control technique still requires further development, particularly when the disturbances are random and non-stationary. Therefore this paper presents a new method for non-stationary seismic random excitations in which LQG control is applied to adjacent tall buildings which are connected together by active hydraulic actuators. The ground motion is induced by non-stationary uniformly modulated white noise excitation of the bedrock which passes through a single layered soil which is regarded as a single-peak filter. This represents an advance on other papers in the literature, which use stationary random white noise or filtered white noise as the ground excitation. The method uses the pseudo excitation method in conjunction with two different precise integration schemes to analyse structural non-stationary seismic random responses via solution of the differential Riccati equations of this transient LQG control process. Unlike previous work in the literature, the performance index used has a finite time region, rather than an infinite one. Reasonable control effects are demonstrated via numerical simulation for two adjacent 20-storey buildings which are connected by hydraulic activators. Copyright q 2006 John Wiley & Sons, Ltd.