09-10-2014, 04:23 PM
The study reported in this thesis is concerned with two problems in the inelastic
dynamic response of structures subjected to earthquake ground motions. The
problems are:
(i) Vibration absorber behaviour in two-storey inelastic structures under
earthquakes.
(ii) Torsional response of inelastic single-storeyed structures subjected to groundmotions.
Some relevant literature on the inelastic response of structures has been reviewed
in Chapter I.
In Chapter II, ‘The inelastic vibration absorber subjected to earthquake ground
motion’ has been studied. Two-storeyed, bilinear-hysteretic structures have been
studied with a view to explore the possibility of using the dynamic vibration
absorber concept in earthquake resistant design. The response of the lower storey
has been optimized for the Taft, 1952, S69E earthquake accelerogram with
reference to parameters such as frequency ratio, yield strength ratio and mass
ratio of the two storeys. The influence of viscous damping has also been
examined.
In chapter III, ‘The inelastic torsional response of a single-storeyed structure with
two degrees-of-freedom’ has been studied. Here, the single-storeyed structure is
assumed to consist of a rectangular slab, supported on series of portal frames,
parallel to one another. The shorter side of the slab is assumed to be parallel to
the span of the frames. The structure is assumed to possess two degrees-offreedom,
viz., a translation along the direction parallel to about a vertical axis
through the mass center. The frames are assumed to follow bilinear-hysteretic,
force-displacement law. The inelastic response of the structure to a horizontal
component of ground motions studied numerically on the computer. The
maximum ductilities of the various frames have been determined and the effects
of various parameters like, eccentricity, yield strength and fundamental period
have been studied for several earthquake inputs. The effect of strengthening the
exterior frames has also been examined.
Chapter IV deals with the ‘Inealstic Torsional Response of a single-storeyed
structure with three degree-of-freedom’. The structure consists of a slab, square
in plan, supported on four columns. In this problem, the two horizontal
displacements of the structure and its rotation around a vertical axis through the
mass center are considered. Interaction between the resistances of the columns in
the two orthogonal directions has been considered. Two horizontal components
of earthquake ground motion have been considered for the input. The
parameters like, eccentricity, yield strength and period of the columns have been
varied and their influence on the response behaviours has been observed. The
responses of the structure to both the horizontal components of the quake and to
only one of the components of the quake have been compared during the study