Evaluation of Accuracy of Simplified Methods of Analysis and Design of Buildings with Damping Systems for Near-Fault and for Soft-Soil Seismic Motions

Keywords: Accuracy.  Simplified methods.  Designs.  Analyses.  Buildings.  Damping systems.  Near field ground motion.  Soft soil ground motion.  Viscous dampers.  Ductility.  National Earthquake Hazard Reduction Program (NEHRP) Recommended Provisions for Seismic Regulations for New Buildings and Other Structures, 2000.  Nonlinear response.

Abstract: The effect of near-field and soft-soil ground motions on structures with viscous-damping systems was examined.  Damping modification factors for damping ratios up to 100% of critical were obtained for sets of near-field and soft-soil ground motions and compared to the values presented in the 2000 NEHRP Recommended Provisions.  A study was carried out for the ductility demand in structures with and without damping systems, where the damped buildings were designed for a smaller base shear than conventional buildings in accordance with the 2000 NEHRP Provisions.  Nonlinear response-history and simplified methods of the 2000 NEHRP Provisions were used to analyze single-degree-of-freedom systems and 3-story moment frames with linear viscous and nonlinear viscous damping systems to acquire knowledge on the influence of near-field and soft-soil ground motions on the accuracy of simplified methods of analysis.  An extensive use of figures is provided throughout the report.