3D-BASIS-ME-MB: Computer Program for Nonlinear Dynamic Analysis of Seismically Isolated Structures

Keywords: Computer programs.  Nonlinear dynamic analyses.  Response-history analyses.  Seismic isolation.  3-D-BASIS-ME-MB.  Superstructures.  Models.  Multiple isolation-system levels.  Viscous dampers.  Axial bearing loads.  Multistory structures.  Bearing uplift.  Software.  Overturning moment effects.

Abstract: This report introduces 3D-BASIS-ME-MB, a new computer program for the dynamic response-history analysis of seismically isolated structures.  Improvements over its predecessor include:  (a) capability to analyze multiple superstructures on multiple isolation-system levels; (b) addition of a new element for modeling the uplift-restraining XY-FP isolator; (c) improvement modeling of viscous damper element; (d) capability to capture overturning moment effects on axial bearing loads, including bearing uplift; and (e) streamlined program output.  Two examples of seismically isolated structures are used for verifying 3D-BASIS-ME-MB and to demonstrate its capabilities, where each is excited under conditions of bearing uplift.  The software program user’s guide, figures and tables are also provided.