NEHRP Clearinghouse
 Title
 Computation of Spatially Varying Ground Motion and FoundationRock Impedance Matrices for Seismic Analysis of Arch Dams.
 File

PB93114825.pdf
 Author(s)
 Zhang, L.; Chopra, A. K.
 Source

National Science Foundation, Washington, DC.,
May 1991,
134 p.
 Identifying Number(s)
 UCB/EERC91/06
 Abstract
 The first part presents a direct boundary element method (BEM) to determine the threedimensional seismic response of an infinitelylong canyon of arbitrary but uniform crosssection cut in a homogeneous viscoelastic halfspace, to P, SV, SH or Rayleigh wave excitations at arbitrary angles with respect to the axis of the canyon. The accuracy of the procedure and implementing computer program is demonstrated. The procedure would enable analytical estimation of the spatial variation of ground motions around the canyon and hence the possibility of exploring the effects of such variation on earthquake response of arch dams. The second part presents a direct boundary element procedure to determine the foundation impedance matrix defined at the nodal points on the damfoundation rock interface. The uniform crosssection of the infinitelylong canyon permits analytical integration along the canyon axis leading to a series of twodimensional boundary problems involving Fourier transforms of the fullspace Green's functions. Solution of these twodimensional boundary problems leads to a dynamic flexibility influence matrix which is inverted to determine the impedance matrix. The accuracy of the procedure is demonstrated. Compared with the threedimensional BEM, the present method requires less computer storage and is more accurate and efficient.
 Keywords
 ; Dynamic response; Arch dams; Boundary element method; Earthquake engineering; Foundations; Green's functions; Soilstructure interactions; Matrices (Mathematics); Earth movements; Mathematical models; Fourier transformation