Effective Formula for Impact Damping Ratio for Simulation of Earthquake-induced Structural Pounding

Abstract

Structural pounding during earthquakes may cause substantial damage to colliding structures. The phenomenon is numerically studied using different models of collisions. The aim of the present paper is to propose an effective formula for the impact damping ratio, as a parameter of the impact force model used to study different problems of structural pounding under seismic excitations. Its accuracy has been verified by four various approaches. Firstly, for the case of collisions between two structural elements, the dissipated energy during impact has been compared to the loss of kinetic energy. In the second stage of verifications, the peak impact forces during single collision have been analyzed. Then, the accuracy of different equations have been verified by comparing the impact force time histories for the situation when a concrete ball is dropped on a rigid concrete surface. Finally, pounding between two structures during earthquakes has been studied. The results of the analysis focused on comparison between dissipated and kinetic energy show relatively low errors between calculated and assumed values of the coefficient of restitution when the proposed equation is used. In addition, the results of the comparison between experimentally and numerically determined peak impact forces during single collision confirm the effectiveness of the approach. The same conclusion has been obtained for the whole impact time history for collision between a ball and a rigid surface. Finally, the results of the comparative analysis, conducted for pounding between two structures during an earthquake, confirm the simulation accuracy when the proposed approach is used. The above conclusions indicate that the proposed formula for impact damping ratio, as a parameter of impact force model for simulation of earthquake-induced structural pounding, is very effective and accurate in numerical simulations in the case of different scenarios.

Determination of Peak Impact Force for Buildings Exposed to Structural Pounding during Earthquakes

“…where m 1 and m 2 are masses of colliding buildings, β stands for the impact stiffness parameter which depends on material properties and geometry of the colliding structures, d is the initial separation gap and ξ denotes the impact damping ratio which can be determined from the formula [36]:…”

“…These factors include the earthquake intensity, frequency contents, PGA value and duration of excitation. The frequency contents and PGA are often considered to be the most important parameters among them [34,36]. Therefore, the analysis described in the present paper was especially focused on the effects of these parameters on pounding-involved structural response under seismic excitation.…”

Study on Methods to Control Interstory Deflections

“…Connections between adjacent buildings by additional stiff beams to absorb energy were also evaluated by Westermo [16]. The author used a special link element, which is able to dissipate energy and decrease impact force during collisions (see also [17,18]). Kasai et al [19] eliminated pounding effects by applying viscoelastic dampers at the level of contact between buildings.…”

Non-Linear Analysis of Inter-Story Pounding between Wood-Framed Buildings during Ground Motion

“…A major reason of pounding between neighboring buildings is related to the differences in dynamic characteristics of the structures. These differences lead to the out-of-phase vibrations and finally to interactions during the time of ground motion [6][7][8][9]. Pounding between adjacent buildings has been investigated for more than three decades applying different models of structures.…”