Modelling of the visco-elastic pendular hybrid system with dissipative rolling elements

Abstract

The construction industry has seen a remarkable development in recent decades, making it possible to build infrastructure elements capable of withstanding considerable demands on traffic, wind or seismic actions. These achievements have been made due to the solutions used for isolation against dynamic actions that may require the structure at a given time. In order to ensure the protection of construction structures against seismic actions, many constructive solutions have been developed which can be mounted inside the resistance structure. These are mechanical systems used for isolation and seismic energy dissipation, which by operation are able to modify structural behaviour at earthquake. A hybrid seismic isolation model is described which is classified under the building base isolation systems category. This system consists of concave roller elements in combination with elastomeric shock absorbing elements. An experimental model has been developed and analysed, and the results are presented in terms of accelerations in time and frequency at the level of the structural elements at which the recordings are made during excitation simulating the action of a seismic event. The isolation system is used on the low model of a bridge or viaduct structure. Analyses are made for different models of insulation system layout at the isolated structure and distinct cases regarding the construction of the component parts regarding the rolling elements in contact with the concave surface. The results are presented for each structural element in part describing the registered values of acceleration due to the excitation on the supporting pier and the superstructure over the three main directions of movement according to the constructive type of the rolling elements that are included in the isolating system. Experimental analysis was performed on a small-scale system under laboratory conditions, based on a set of simplified assumptions. The advantage of this approach is supported by multiple possibilities of simulation of real dynamic loading situations, static and dynamic loading states, structural and functional schemes and functional configurations of the supporting and isolation systems against dynamic actions. Thus, the transfer of experimental results from reduced models to real systems through mathematical and computer models associated with them is ensured by appropriate transfer functions.