Triaxial seismic response history analysis of reinforced concrete mat-structure interaction model

This research proposes a novel tri-axial response history analysis for the multi-storied (i.e. 4, 6, 8, and 12-storied) mat-founded reinforced concrete (RC) structures to evaluate story drift, story shear, base shear and overturning moment. For this purpose, the Kobe and Loma Prieta seismic excitations are applied at the base of structures to perform direct integrated time history analysis by using the Newmark method. The numerical analysis of the proposed model is verified with the previous shake table test result of recorded maximum acceleration at first floor level. The maximum difference in validation results between previous and present studies is found to be 3.61 %, which may indicate a good accuracy of the numerical analysis. The tri-axial loading shows the higher response compared to the uni-axial and bi-axial loadings due to the equality of directional forces. The average differences in numerical results between tri-axial and bi-axial loadings are found to be 18.5 %, 18.4 %, and 18.3 % for story drift, story shear, and overturning moment, respectively. The sensitivity analysis proves the reliability of parameters used in the numerical analysis.