Dimensional Analysis Of Earthquake-induced Pounding Between Adjacent Buildings

Numerous investigations have shown that the pounding between adjacent structures is one of the main causes leading to the structural damage. Structural pounding between adjacent, insufficiently separated buildings during earthquakes has been widely reported. The phenomena of earthquake-induced structural pounding have attracted the researchers’ attention, and been widely studied during the past years. Pounding is a highly nonlinear process involving numerous material and geometric factors. One of the major challenges in studying the pounding response is how to tackle a large variety of parameters that govern the structural pounding behavior. The promising approach to deal with this parametric complexity is by the dimensional analysis, which offers a condensed presentation of the seismic response and brings forward the fundamental physical similarities that describe the structural behavior. So far, the dimensional analysis approach in the study of the structural pounding is only focused on the elastic and inelastic single-degree-of-freedom(SDOF) oscillators. One limitation of the current study is that the transient stresses and deformations in the pounding bodies cannot be considered, meaning that the structural response during the contact cannot be traced, and it can not be used to analyze the pounding response between adjacent multi-degree-of-freedom(MDOF) buildings.In this study, the contact element method is utilized. It is capable of considering the deformation between the colliding bodies, and thus the structural responses can then be traced. With the dimensional analysis, the peak structural response parameters of the pounding structures are characterized by a set of dimensionless quantities, and the interaction between the oscillators is explicitly described. The effects of different parameters on the oscillator’s response are illustrated using three well-divided spectral regions. The main contents of this study are as follows:(1) The dynamic response of an elastic pounding oscillator subjected to the harmonic excitation is investigated with the dimensional analysis. Analytical solutions to the dimensionless contact time, displacement and velocity response are derived, which are further verified against the numerical simulation. The parametric studies are conducted to study the effects of contact element parameters.(2) The inelastic pounding response between two and more inelastic SDOF oscillators is studied by the dimensional analysis and the contact element method. The differences between the single-side pounding and double-side pounding are compared. The effects of different structural distribution and properties are analyzed and the fundamental physical similarities that describe the structural behavior are revealed.(3) A series of shaking table test is conducted to investigate the pounding responses between two adjacent 1/3 scale 3-storey and 2-storey single-bay steel framed model structures, and the central pounding and torsional pounding are considered. The pounding responses(displacement, acceleration and pounding force) of the frames under various earthquake intensity levels are measured.(4) The seismic pounding response of adjacent MDOF systems with bilinear inter-storey resistance characteristic is investigated with the aid of the dimensional analysis. The predictions derived from the theoretical method are compared with the experimental results. Parametric studies are conducted to investigate the effects of the structural characteristics. The remarkable self-similarity property for bilinear MDOF systems with inelastic collision is uncovered.