M Abdel-Rohman - Professor, College of Engineering and Petroleum, Kuwait University, Kuwait

In this paper, the nonlinear vibrations response of the suspended cable and the suspension bridge deck due to vertical moving loads are shown. To control the bridge nonlinear vibrations, control mechanisms are suggested to generate control forces on the bridge. One mechanism consists of a rigid vertical link connecting the bridge deck with the suspended cable. Another control mechanism consists of pre-tensioned cables and a rigid link to form a king-post truss. The active control force is generated by a hydraulic actuator, which is installed between the rigid link and the bridge deck. The hydraulic actuator response should be designed to keep the structure safe, stable and serviceable as desired. The actuator’s response is designed to depend on measurements received from sensors installed at specific locations on the structure. Since the design of the control law for nonlinear systems is more involved, this paper presents a simple design for the active control force to control the nonlinear dynamic response of the suspension bridges due to the moving loads. The design of the controller is based on the feedback of the velocity measurements taken at the control force location. The design is made first for a linear model before applying it on the actual nonlinear model. The method is applied on the two proposed control mechanisms. Comparison between the controlled responses using the two controllers indicated that the feasibility of the active control depends mainly on the type of the control mechanism and the design method of the control actions.

Feedback Control, Moving Loads. Nonlinear Vibrations Control, Suspension Bridges