A new approach for base isolation design in building codes

Abstract

Base isolation is now a well-established technology for the structures earthquake protection. Several national building codes now include chapters on base isolation, to promulgate and expand seismic isolation technique and enhance its application to buildings. After gathering more information on the building codes in Japan, China, IBC2009, Italy, Taiwan, and Algeria (RPA 99), and using a benchmark building, a comparative study is conducted to understand and illustrate the differences in the isolation provisions of the building codes. The building’s characteristics such as weight, height, hysteresis properties and soil condition are fixed in all cases, and the properties of the lead rubber bearing isolation devices are also kept constant. In this research, a new approach for the design of base-isolated buildings has been proposed in adequacy with the Algerian seismic regulations. It is essentially based on both the linear equivalent method for determining the design displacement using an iterative process on one hand and time history analysis methods on the other hand, also knowing that the response reduction factor is very important in the widely used equivalent linear analysis method. This new method was validated by a numerical modeling, which is a comparative study with several regulations in the world, which showed very satisfactory results in design displacement and base shear force, which agree very well with the various regulations.