Hybrid control of seismic-excited bridge structures

Recently, several hybrid protective systems have been explored for applications to seismic-excited bridge structures. In particular, two types of aseismic hybrid protective systems have been shown to be quite effective: (i) rubber bearings and variable dampers (or actuators), and (ii) sliding bearings and actuators. In this paper, control methods are presented for these hybrid protective systems. The control methods are based on the theory of variable structure system (VSS) or sliding mode control (SMC). Emphasis is placed on the static (direct) output feedback controllers using only the information measured from a few sensors without an observer. Simulation results demonstrate that the control methods presented are robust with respect to system parametric uncertainties and the performance is quite remarkable. Sensitivity studies are conducted to evaluate the effectiveness of hybrid protective systems and passive sliding isolators for reducing the response of seismic-excited bridge structures. The advantages of each protective system are demonstrated by simulation results for a wide range of earthquake intensities.     

Earthquake simulation test of circular reinforced concrete bridge column under multidirectional seismic excitation

1 Introduction Since the 1971 San Fernando earthquake, a signi?cant amount of research has been conducted on the ductility capacity of reinforced concrete bridge columns, resulting in signi?cant advances in the seismic design of bridges. Since most tests have been done in static or quasistatic conditions and unidirectional loading conditions, however, no method that properly evaluates the effect of multidirectional dynamic loading has been developed, and design recommendations on this effect a…