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Proceedings of the International Conference on
Advances and New Challenges in Earthquake 471
Engineering Research, Hong Kong Volume
SEISMIC RESPONSE OF MULTISTOREY MASONRY
BUILDING WITH RESTRICTED BASE SLIDING
M. Qamaruddin, S. Ahmad, H. Irtaza and S. M. Waseem
Department of Civil Engineering, Z. H. College of Engineering and Technology,
Aligarh Muslim University, Aligarh 202002, India
ABSTRACT
In the present investigation, a multistory masonry building system is considered in which a
smoothened surface is created at the top of the substructure and the superstructure rests at this level
and restricted sliding is permitted with fnctional resistance. The restricted sliding base system is
idealized as a discrete mass mathematical model with two degree of freedom for computing its seismic
response. The shear walls provide the spring action in the system. The total mass of the superstructure
of the building, that is, the mass of all the stones, except the bottom half of the ground story mass, is
lumped as top mass in the model and mass of the remaining bottom half portion of the ground story is
lumped as bottom mass in the model. The bottom mass is assumed to rest on a plane with dry frictional
damping to permit restricted sliding of the system. The seismic response of multistory masonry
building with restricted sliding subjected to Koyna and El Centro earthquakes is computed employing
this mathematical model treating the frictional resistance as rigid plastic. It turns out from this study
that the restricted sliding base system is effective in reducing the seismic force acting on the building
with low values of coefficient of friction. The seismic response of such a system is much reduced
compared to the fixed base buildings with the same parameters.
1. INTRODUCTION
In past earthquake in India, unengineered masonry buildings were mostly damaged
due to a variety of factors, such as. their short fundamental period and mostly lying in the dominant
frequency range of strong earthquakes; very low tensile and moderate shear strength; some times not
sufficiently high compressive strength; usually poor workmanship, etc. To improve the behavior of
masonry structures under seismic forces, strengthening measures have been proposed. In spite of all
these measures, masonry buildings can still be cracked during the earthquake. Such damage might be
avoided if major part of the seismic energy is dissipated during earthquake One possibility to achieve
this objective is by means of base isolation technique, which consists of decoupling the structures from
the damaging effect of the earthquake. In the last few decades, various researchers have proposed
varieties of isolation devices.
In several major earthquake occurrences in developing countries like India and China, a beneficial
behavior of the low-rise buildings which could slide as rigid bodies over their foundations was
observed during some past severe earthquakes, viz., the Dhubri Earthquake in Assam in 1930 [2], and
in Bihar-Nepal Earthquake in 1934. The damage study by Gee [2] and the observations made in China
by LiLi [3], showed that those buildings in which the possibility of movement existed between the
superstructure and the substructure suffered less damage than those buildings in which no such
freedom of movements existed. Arya, Chandra and Qamaruddin [1], LiLi [3] and Qamaruddin [5] have