A design methodology for the application of Kansas State University's Stiffness Decoupler to masonry structures.

摘要

Lightly reinforced and unreinforced masonry buildings have generally not performed well in earthquakes. Evaluation of past performance of masonry structures has led to more stringent design and construction requirements in the current model building codes, and has raised concerns about the performance of existing lightly reinforced and unreinforced masonry buildings in future earthquakes.; Kansas State University's (KSU) Stiffness Decoupler for the Base Isolation of Structures (SDBIS) was designed to break the dependency between stiffness and the required strength of the support system for the superstructure, effectively reducing the acceleration and force transferred into the superstructure during a seismic event. The sliding system uses a passive method to provide damping and dissipate some of the kinetic energy to reduce relative displacements. The SDBIS system stiffness is designed to control the desired natural period of the isolated structure and to provide a self-centering effect that will recover the majority of the induced displacement. The main structural components of the SDBIS system are constructed of steel, Teflon, and concrete, making it easy to construct and durable.; In order to apply the SDBIS to the masonry building industry, dynamic tests were performed to evaluate the structural response of a full-size one-story masonry model that was supported by the SDBIS. The concrete masonry model measured approximately eight feet by eleven feet in plan, and was fifteen feet tall. Measured results included base accelerations, top accelerations, displacements, and wall strains for the isolated structure when subjected to the Taft, El Centro, Pacoima Dam, and 77 percent Northridge earthquake ground motions. The results are compared with the observed response of typical masonry structures in recent earthquakes, the expected response based on code analysis methods, and the response of the model with reduced input magnitudes when the SDBIS was deactivated. Test results were then used to develop a practical design method for structural engineers to use in applying the SDBIS to new and existing masonry structures.