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.