Seismic analyses and instrumentation of the Patillas earth dam

Abstract

This thesis presents the results of seismic analyses performed for an earth dam located in Patillas, Puerto Rico. This embankment dam was built using hydraulic filling between 1912 and 1914. The dam geometry and material properties were estimated based on an exhaustive review of existing records and reports for this dam. The seismic evaluation of the dam consisted of static and pseudo-static limit equilibrium analyses, dynamic 2D finite element analyses with equivalentlinear models to account for soil non-linearity, and Newmark-type sliding block analyses to estimate expected deformation levels. The analyses considered different levels of seismic excitation based on return periods of 2,500 and 10,000 years. From the studies performed in this thesis the Patillas Dam is considered reasonably well suited to withstand large earthquake events. However, liquefaction assessment was not included in the scope of this research. In addition to the seismic evaluation, this thesis included instrumentation layout and installation for the dam. The thesis also presents results from ambient vibration tests which yield predominant periods for the dam similar to those obtained in the seismic analyses carried out for this thesis.