Evaluation of Geometry and Essential Parameters of Topographic Irregularities for Generalization Seismic Results of Manjil Earthquake for Regions with Soil Type II

In order to study geometry of topographies on the seismic site response and evaluate essential parameters used for generalizing seismic results to the topographic irregularities, several numerical finite element studies have been performed by ABAQUS program, the results are presented in the form of the time history and dimensionless graphs. In this paper rectangular, trapezoidal and triangular topographies are studied with different heights (20-100 m) and different angles (15-75 degrees) to evaluate effect of shape ratio, height, length and angle of slope on the seismic response. Applied Seismic motion is the record of Manjil earthquake in horizontal direction. Besides, models are two-dimensional and flexible. ABAQUS infinite elements can be used to define infinite boundaries in the dynamic problems. These elements have elastic behavior and absorb the wave energy so that they act as absorbent boundaries. Researchers such as Nielsen, Preisig and Jeremic have examined the performance of these elements. Actually, if slope angle of topographic irregularities is increased in how slope length of topographies is decreased, seismic response will be weakened even though shape ratio is boosted. Also slope height of topographic irregularities is increased in how slope length of topographies is boosted too; seismic response will be amplified even though shape ratio is constant.