Original and Innovative Structural Concepts for Design, Non-Linear Analysis, and Construction of Multi-Story Base Isolated Buildings

Abstract

Seismic isolation of structures is becoming a more common method of providing protection from earthquake damage. Starting from 1994, 53 buildings and structures have been designed by the author of this chapter with application of base or roof isolation systems. Of these designed buildings, the total number of already constructed and retrofitted buildings has reached 45. The number of seismically isolated buildings per capita in Armenia is one of the highest in the world. Together with that seismic isolation laminated rubber-steel bearings (SILRSBs) different by their shape and dimensions, as well as by damping (low, medium and high) were designed and about 5000 SILRSBs were manufactured in the country, tested locally and applied in construction. since 2003 seismic isolation technologies were designed and then extensively applied in construction of multi-story buildings. these are: base isolated residential complexes, business centers, hotels, schools, and hospital buildings. Original and innovative structural concepts, including the new approach on installation of seismic isolation rubber bearings by clusters, were developed and designed for construction of these base isolated buildings and they are described in the given chapter. The advantages of this approach are listed and illustrated by the examples. It is mentioned that suggested new structural solutions in seismic isolation are bringing to significant savings in construction cost. The earthquake response comparative analyses were carried out for some of the considered buildings in two versions (i.e., when the buildings are base isolated and when they are fixed base). Several histories were used in the analyses and for both cases the buildings were analyzed also according to the requirements of the Armenian Seismic Code. Comparison of the obtained results indicates the high effectiveness of the proposed structural concepts of isolation systems and the need for further improvement of the Seismic Code provisions regarding the values of the reduction factors. A separate section in the chapter dedicated to the design of high damping laminated rubber-steel bearings and to results of their tests.