الفهرس 
CHAPTER (1) INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The most important property of the base-isolation system is to make the
base more flexible than the elements of the superstructure, and it must still be
stiff enough to resist typical pounding forces, wind loadings, and similar low-
amplitude horizontal forces. However, the potential consequences of
earthquake-induced poundings on seismically isolated buildings can be much
more substantial, and, thus, should be assessed.
This thesis investigates, through numerical simulation, firstly, the effect
of the potential pounding incidences on the building response and a comparison
between two fixed base buildings two story and two seismically base isolated
buildings two story under this phenomenon. A parametric study is conducted
on this part to investigate the effect of the important parameters of the adjacent
structures on the pounding response. These parameters are the isolator shear
capacity, the post-pre stiffness ratio, the ratio between the masses of the
colliding structures, separation distance between the colliding structures and
the superstructure and base damping ratios. Also, the study investigates the
effect of the presence of the viscous dampers at the points of the collision on
the reduction of the pounding force. A specialized program has been made in
order to efficiently perform numerical simulation and parametric studies on the
control system. The effects of certain parameters have been investigated using
the developed software such as damper yield force, damper stiffness and post-
pre stiffness ratio to find the optimum parameter of the viscous damper.
The simulation have revealed that. even if a sufficient gap is provided,
with which poundings with the surrounding adjacent buildings .at the base of
the building could be avoided. this does not ensure that the building will not
eventually collide with neighboring buildings due to the deformations of their
superstructures. Also, Pounding increases the response of the lighter floors of
the adjacent base isolated buildings while decreases the response of the heavier
floors, but pounding increases the response of the floors of the adjacent fixed
base buildings. Finally, the presence of viscous dampers at the floor levels at
the points of contact increase the dispersal of energy generated by the collision.