Shake table experiment of a 1/20-scale Koyna dam model

Shake table experimental results of a 1/20-scale model of Koyna dam are presented in this paper. Experiments were conducted to simulate the dynamic behavior of a nonoverflow monolith due to sinusoidal horizontal base excitations normal to the dam major axis. The value of the excitation frequency was selected slightly higher than the first in-plane fundamental frequency of the model. The amplitude of the excitation was increased for each test run until failure occurred at a peak excitation level of 0.16g. The model failure mode closely resembled that observed in the prototype dam. The similitude scaling relations required an innovative material design, one that scaled the model modulus of elasticity by the length factor and maintained the prototype material density. The simulated dynamic response provides realistic data for validation and calibration of numerical procedures currently used to model the seismic performance of concrete gravity darns. This paper describes the experimental results and identifies the dynamic simulate the monolith due to characteristics of the model.