Separation between Adjacent Nonlinear Structures for Prevention of Seismic Pounding

Four existing methods to calculate critical separation distances between adjacent nonlinear hysteretic structures are evaluated through Monte-Carlo simulations, for which seismic excitation is characterized as a nonstationary random process. All the methods use the well-known Double Difference Combination rule, but follow different approaches to calculate the correlation coefficient ρ. Results show that none of the methods evaluated is completely satisfactory in the sense that they are not capable of providing consistently conservative estimates of the critical separation distance for all possible values of relevant parameters. A new method, which consists of using values of parameter ρ derived from empirical estimates obtained through numerical simulations, is then proposed and examined. Results show that the proposed method provides consistently conservative estimates of critical separation distances, the degree of conservatism being slight in most cases. These desirable properties are found to hold for a variety of wide-band seismic excitations.