FREE VIBRATION ANALYSIS OF SHEAR WALLS WITH SHORT PIERS

The equations of the lateral deflection curve of the short pier shear wall under a lateral concentrated load at any level are derived by employing a continuous approach. Lateral flexibility matrixes for the dynamic analysis are also obtained by repeatedly calculating the lateral unit load on the wall at each level where a lumped mass located. Dynamic analyses are implemented for short pier shear walls with different parameters, called the integrative coefficient and the pier strength coefficient related to the dimensions of walls. The influences of two coefficients on the dynamic performances of the structure are studied. Results indicate that with the increase of the integrative coefficient, the periods of top two modes apparently decrease but the other periods of higher frequency modes show little variation when the pier strength coefficient remains constant. Similarly, if the integrative coefficient is constant, the top two periods of the free vibration decrease with the increase of the integrative coefficient but the other periods of higher frequency modes show less variation.

FEM and ANN analyses of short and tall geosynthetic reinforced soil walls:Evaluation of various effective aspects and ASSHTO acceptable design methods

In addition to confined investigations on tall geosynthetic reinforced soil(GRS)walls,a remarkable database of such walls must be analyzed to diminish engineers’concerns regarding the American Association of State Highway and Transportation Officials(AASHTO)Simplified or Simplified Stiffness Method in projects.There are also uncertainties regarding reinforcement load distributions of GRS walls at the connections.Hence,the current study has implemented a combination of finite element method(FEM)and artificial neural network(ANN)to distinguish the performance of short and tall GRS walls and assess the AASHTO design methods based on 88 FEM and 10000 ANN models.There were conspicuous differences between the effectiveness of stiffness(63%),vertical spacing(22%),and length of reinforcements(14%)in the behavior of short and tall walls,along with predictions of geogrid load distributions.These differences illustrated that using the Simplified Method may exert profound repercussions because it does not consider wall height.Furthermore,the Simplified Stiffness Method(which incorporates wall height)predicted the reinforcement load distributions at backfill and connections well.Moreover,a Multilayer Perceptron(MLP)algorithm with a low average overall relative error(up to 2.8%)was developed to propose upper and lower limits of reinforcement load distributions,either at backfill or connections,based on 990000 ANN predictions.