Comparison of non-orthogonal smeared crack and plasticity models for dynamic analysis of concrete arch dams

A special three-dimensional finite element program is developed to study the seismic response of concrete arch dams. Two types of continuum mechanics non-linear techniques are incorporated in the program, i.e. non-orthogonal smeared crack and elasto-plastic models. The formulation is presented initially and accuracy of the models and their correct implementations are verified by analyzing a notched beam and comparing its results with available experimental data. Following the satisfactory results of the beam analysis, the program is applied to a practical problem, viz. the non-linear behavior of the 130 m high Shahid Rajaee arch dam in Iran, subjected to the Friuli–Tolmezzo earthquake. Two cases of non-orthogonal smeared crack model are implemented for the dam, namely, ordinary and fictitious approaches. Meanwhile, an elastic–perfectly plastic model for mass concrete is also applied. The results are compared with those obtained from a linear elastic analysis under the same excitation. Based on the results, it is concluded that the non-orthogonal smeared crack approach can redistribute the state of stresses and produces a more realistic profile of stresses in the dam. Further, the elasto-plastic model could reduce significantly the high amount of overstressing noticed in the linear analysis. However, the elasto-plastic model is not perceptibly activated in the compressive state of stresses. It is also observed that a drift in the crest displacements is the prominent consequence of cracking or plasticity of the dam.