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dissertation summary of india iit kanpur

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wangjianping 发表于 2009-3-13 22:03:35 | 显示全部楼层 |阅读模式
no.1  Seismic Design of Strong-Axis Welded Connections in Steel Moment
Resisting Frame Building
[Jaswant Narayan Arlekar; 2002; Supervised by C. V. R. Murty]
Seismic design of welded connections in steel moment resisting frames (MRFs)
has received considerable attention during the past decade. One of the main
reasons identified for the poor performance of beam-column joints during
earthquakes was the vulnerability of welds between beam flange and column to
premature brittle fracture. The tri-axial state of stress in this region restrains the
expected ductile yielding of the weld material there. The major emphasis of past
research on this subject has been the improvement of design of beam-to-column
connections to achieve superior performance of steel MRFs during strong ground
shaking.
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 楼主| wangjianping 发表于 2009-3-13 22:05:20 | 显示全部楼层
This research addresses welded strong-axis beam-to-column and column-tofoundation
connections. Refined truss models are developed for representing the
flow of forces near the joint regions. In beam-column joint region, the inelastic
stress distribution is symmetric about the beam neutral axis. For the design of
beam-to-column connections, the load flow is represented by an Improved Ktruss
model. But, in the column-foundation joint region, the presence of
combined action of axial load, shear and bending moment results in an
unsymmetric inelastic stress distribution. Hence, for the design of column-tofoundation
connections the load flow is represented by a Twin Truss Model –
one for axial load and bending moment and the other for shear.
New geometric configurations are proposed for welded strong-axis beam-tocolumn
and column-to-foundation connections based on inelastic finite element
analyses. The chosen connection elements reinforce the joint region and reduce
the stress intensity, thereby improving the effectiveness of the connections to
transfer loads without brittle failure in the weld region. Step-wise procedures are
provided for the seismic design of both of these connections. These design
procedures are based on capacity design concept, and incorporate the effects of
material overstrength, strain-hardening and member instability.
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 楼主| wangjianping 发表于 2009-3-13 22:05:50 | 显示全部楼层
Nonlinear finite element analyses are conducted to evaluate the performance of
beam-column joint subassemblages, wherein the connections are designed using
the proposed procedure. Monotonic pushover displacement-based analysis is
used to compare the effectiveness of the beam-to-column connections in
transferring loads from the beam to the column. Assumptions made in the
proposed design procedure are confirmed. Cyclic displacement-based pushover
analysis is conducted for beam-column joint subassemblages and frame storey
subassemblages. The proposed connection configuration designed using the
proposed procedure showed excellent performance in contrast to that of the
connection configuration currently being used in practice and designed by
existing code procedures. Nonlinear finite element analyses of columnfoundation
joint subassemblage are preformed. Critical loading conditions
encountered by these subassemblages during strong earthquake shaking are
modeled. The column-foundation joints, designed using the proposed procedure,
are found to be able to sustain lateral drifts larger than 4%, while retaining
significant reserve capacity.
The seismic performance of steel MRF buildings can be significantly improved
by adopting the proposed reinforced joint connection configuration in
conjunction with the proposed procedure for their design. The connections so
achieved are capable of avoiding the premature brittle fracture of the welds at
the column face.
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 楼主| wangjianping 发表于 2009-3-13 22:06:42 | 显示全部楼层
no.2  Wavelet-Based Non-Stationary Seismic Response of Structural System
[Biswajit Basu; December 1997; Supervised by Vinay K. Gupta]
This study proposes a wavelet-based approach for the estimation of the response
of linear and non-linear structural systems which are subjected to an earthquake
ground motion process modelled by its wavelet coefficients. An orthogonal
wavelet basis function has been proposed for this purpose. The proposed
formulation considers a more realistic modelling of the ground motion, and is
thus more generalized as compared to the earlier methods based on the use of
frequency-independent modulating functions. The linear structures have been
idealized by single-degree-of-freedom (SDOF) and classically damped multidegree-
of-freedom (MDOF) systems for the purpose of formulation. Expressions
have been derived for i) the representation of the input excitation through
wavelets, ii) relationship between the wavelet coefficients of the excitation and
response processes, and iii) instantaneous mean- square value and power
spectral density function (PSDF) of the response. The moments of the PSDF of
response are used to predict the response statistics of interest. Non-linear
systems with non-linearity in stiffness or damping have been considered via
linearization to systems with time-varying parameters. A Duffing oscillator has
been considered to illustrate the performance of the proposed linearization in
case of non-linear stiffness. For considering systems with non-linear damping,
pure-friction (P-F) base-isolated structural systems have been considered. Those
are modeled as i) a rigid block on a friction base, and ii) a two-degree-of-freedom
(2-DOF) base- isolated system. The effectiveness of the base-isolation system
and the effect of the frequency non-stationarity on the non-linear response have
also been studied in detail. It has been clearly shown how the ignoring of
frequency non-stationarity in the ground motions may lead to inaccurate nonlinear
response calculations. Various formulations proposed in this study have
been illustrated through comparison of the (wavelet-based) stochastic estimates
with those obtained from time-history simulations.
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 楼主| wangjianping 发表于 2009-3-13 22:07:33 | 显示全部楼层
no.3  Stochastic Response of Suspension Bridges to Spatially Varying Earthquake
Exicitations
[Manish Shrikhande; July 1997; Supervised by Vinay K. Gupta
The stochastic response of a suspension bridge including the dynamic soilstructure
interaction (SSI) effects to spatially varying earthquake excitations has
been studied. Since the currently available procedures for the stochastic analyses
of structural systems cannot be generalized to the case of suspension bridges,
particularly when the SSI effects have to be accounted for, an alternative
approach has been formulated in frequency-domain for the non-stationary
seismic analyses of simple SDOF and MDOF systems. This approach is then
extended to the formulation for suspension bridges by considering fixed-base
modes and by modifying the excitations at different supports for the soilstructure
interaction effects. The proposed formulation requires the
characterization of ground motion in form of a coherency function, and the
values of peak ground acceleration (PGA), Fourier spectrum and strong motion
duration. The proposed approach has been validated via time-history analyses
for two sets of synthesized spatially correlated accelerograms. For generating
these accelerograms, a new approach based on the spectral decomposition
technique has been proposed. This approach can be used to synthesize
ensembles of realistic and spatially correlated accelerograms at several closely
spaced stations. The accelerograms are made consistent- with a specified
coherency function by using the duration spectrum and the phase characteristics
of a previously recorded accelerogram. Further, the generated accelerograms at
the reference station are also made consistent with the specified design spectrum
in the mean sense.
It is found from a numerical study that the dynamic soil-structure interaction
effects can considerably alter the response of suspension bridges founded on soft
soils. Further, the suspension bridge vibrations in the vertical plane may not
always be governed by the longitudinal ground motions as the relative
contributions of the vertical ground motions increase with increasing soil
compliance. It has also been found that the spatial variation of ground motion
may significantly influence the response modification due to soil-structure
interaction effects. For soft soils, and more uniform and coherent motions, these
effects may actually lead to substantial amplifications in the bridge response
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 楼主| wangjianping 发表于 2009-3-13 22:08:30 | 显示全部楼层
no.4  Stochastic Response of Suspension Bridges to Spatially Varying Earthquake
Exicitations
[Manish Shrikhande; July 1997; Supervised by Vinay K. Gupta
The stochastic response of a suspension bridge including the dynamic soilstructure
interaction (SSI) effects to spatially varying earthquake excitations has
been studied. Since the currently available procedures for the stochastic analyses
of structural systems cannot be generalized to the case of suspension bridges,
particularly when the SSI effects have to be accounted for, an alternative
approach has been formulated in frequency-domain for the non-stationary
seismic analyses of simple SDOF and MDOF systems. This approach is then
extended to the formulation for suspension bridges by considering fixed-base
modes and by modifying the excitations at different supports for the soilstructure
interaction effects. The proposed formulation requires the
characterization of ground motion in form of a coherency function, and the
values of peak ground acceleration (PGA), Fourier spectrum and strong motion
duration. The proposed approach has been validated via time-history analyses
for two sets of synthesized spatially correlated accelerograms. For generating
these accelerograms, a new approach based on the spectral decomposition
technique has been proposed. This approach can be used to synthesize
ensembles of realistic and spatially correlated accelerograms at several closely
spaced stations. The accelerograms are made consistent- with a specified
coherency function by using the duration spectrum and the phase characteristics
of a previously recorded accelerogram. Further, the generated accelerograms at
the reference station are also made consistent with the specified design spectrum
in the mean sense.
It is found from a numerical study that the dynamic soil-structure interaction
effects can considerably alter the response of suspension bridges founded on soft
soils. Further, the suspension bridge vibrations in the vertical plane may not
always be governed by the longitudinal ground motions as the relative
contributions of the vertical ground motions increase with increasing soil
compliance. It has also been found that the spatial variation of ground motion
may significantly influence the response modification due to soil-structure
interaction effects. For soft soils, and more uniform and coherent motions, these
effects may actually lead to substantial amplifications in the bridge response
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 楼主| wangjianping 发表于 2009-3-13 22:10:36 | 显示全部楼层
no.5  A Ductility And Displacement Based Design Procedure For Seismic Design of
Reinforced Concrete Frames
[Gehad Ez-Eldin Rashad; November 1993; Supervised by Sudhir Kumar Jain]
A displacement and ductility based design procedure (DDBDP) for reinforced
concrete frames has been proposed which explicitly considers strength, stiffness,
ductility, and structural configuration. The procedure satisfies the design
requirements ate two limit states; serviceability limit state (SLS) and ultimate
limit state (ULS). To obtain the outer envelop of base shear - roof displacement
relationship, a displacement-control non-linear quasi-static analysis has been
proposed. The analysis is carried out by imposing a lateral displacement profile
on the structure in small increments. The displacement profile is proportional to
the first mode shape of the structure, when it is elastic. Under inelastic
conditions, the profile is also a function of mode shape of the "yielding" structure
at that stage. A computer program has been developed to carry out this quasistatic
analysis. The base shear - roof displacement relationship, so obtained is
used to assess the suitability of design for stiffness, strength modelled by the
ULS. To account for effect of low initial stiffness modelled by the non-linear
analysis procedures on drift requirements at ULS, a correction based on a more
realistic linear analysis has been suggested.
A limited parametric study has been conducted to assess the displacementcontrol
quasi-static non-linear procedure with request to the time-history
analysis. The displacement-control quasi-static procedure is seen to give
reasonably accurate behavior and is more consistent than the force-control
procedure
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 楼主| wangjianping 发表于 2009-3-13 22:10:52 | 显示全部楼层
no.5  A Ductility And Displacement Based Design Procedure For Seismic Design of
Reinforced Concrete Frames
[Gehad Ez-Eldin Rashad; November 1993; Supervised by Sudhir Kumar Jain]
A displacement and ductility based design procedure (DDBDP) for reinforced
concrete frames has been proposed which explicitly considers strength, stiffness,
ductility, and structural configuration. The procedure satisfies the design
requirements ate two limit states; serviceability limit state (SLS) and ultimate
limit state (ULS). To obtain the outer envelop of base shear - roof displacement
relationship, a displacement-control non-linear quasi-static analysis has been
proposed. The analysis is carried out by imposing a lateral displacement profile
on the structure in small increments. The displacement profile is proportional to
the first mode shape of the structure, when it is elastic. Under inelastic
conditions, the profile is also a function of mode shape of the "yielding" structure
at that stage. A computer program has been developed to carry out this quasistatic
analysis. The base shear - roof displacement relationship, so obtained is
used to assess the suitability of design for stiffness, strength modelled by the
ULS. To account for effect of low initial stiffness modelled by the non-linear
analysis procedures on drift requirements at ULS, a correction based on a more
realistic linear analysis has been suggested.
A limited parametric study has been conducted to assess the displacementcontrol
quasi-static non-linear procedure with request to the time-history
analysis. The displacement-control quasi-static procedure is seen to give
reasonably accurate behavior and is more consistent than the force-control
procedure
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 楼主| wangjianping 发表于 2009-3-13 22:13:45 | 显示全部楼层

theses summary of india iit kanpur

no.1  Improved Seismic Coefficient Method to Incorporate Deformation Types and
Higher Mode Effects
[Subhatosh Nandi, December 2005, Supervised by C. V. R. Murty]
Current seismic code specifications for design of buildings use a design base
shear spectrum based on single-degree-of-freedom (SDOF) systems and specify
the lateral force profile using an assumed fundamental mode shape. The present
study proposes an improvement to the above method, which is known as the
Equivalent Lateral Force (ELF) Method, by incorporating the effects of
deformation type and higher modes. The study idealizes buildings as uniform
vertical cantilevers which; being continuum systems, have infinite number of
deformation modes of which the significant modes are included in the analysis.
A shear factor β is used to characterize the relative contributions of flexural and
shear deformations, β = 0 implying pure flexural behaviour andβ = ∞ , pure
shear. Closed form solutions of the governing differential equation of cantilevers
subjected to ground motion are obtained and time history analyses are
performed. The base shear response spectra and lateral force distributions
obtained from the study are compared with code provisions.
Code spectra are found to overestimate the base shear at low natural periods and
underestimate at high natural periods. The effects of higher modes are significant
for systems with high fundamental natural periods. Spectral ordinates are found
to increase with increasing β at low natural periods and with decreasing β at
high natural periods. Lateral force distribution profiles resulting from the study
are seen to be considerably influenced by higher modes andβ , especially at high
natural periods. The study suggests the lateral force at the base be assigned a
non-zero value, which is a departure from code profiles. In general, code profiles
are seen to underestimate lateral force at lower storeys and overestimate them at
higher storeys. Based on a limited number of ground motions, the study
proposes analytical expressions to obtain the proposed alternative base shear
spectrum and lateral force profiles.
A revised drift spectrum has been suggested as a complement to the response
spectrum. The original drift spectrum was based on wave propagation analysis
of a shear cantilever. This study recommends the use of modal time history
analysis using the vertical cantilever mentioned above to derive the drift
spectrum. This approach is closer to engineering practice and can give drift
spectra for various deformation types while the original spectrum was limited to
shear buildings. Moreover, the new drift spectrum requires ground acceleration
records alone, while the original spectrum required ground displacement and
velocity traces.
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 楼主| wangjianping 发表于 2009-3-13 22:14:37 | 显示全部楼层
no.2  Enahncement of Flexural Capacity of Undamaged RC Column by A
Composiste Steel Caging Technique
[Pasala Naga Prasad, October 2005, Supervised by Sudhir K. Jain and Durgesh C. Rai]
The upgradation of reinforced concrete buildings is frequently connected with
requirements for their new utilization and for increasing load-carrying capacity
of a structure. From the past earthquakes, most of the RC structures suffered
damage or complete collapse mainly due to the inadequate strength and ductility
of the column which play a vital role in the stability of the existing or
deteriorated buildings. The existing vulnerable RC structures which have or
could suffer damage due to inadequate strength can be repaired or upgraded by
enhancing the ductility and/or capacity of critical column by any of the repair
and strengthening techniques. Steel caging composite technique, is one of the
various methods used for strengthening of rectangular reinforced concrete
column. This technique is composed of steel angles and transverse steel flats as
battens. In the present experimental study a rectangular reinforced concrete
column is studied for flexural strength and ductility in the presence of axial load.
The enhancement of strength of the column section is determined with the help
of a theoretical model proposed for confinement which is similar to the
confinement provided by the ordinary stirrups onto the concrete core. The
present experimental study verifies the theoretically prediction strength of the
strengthened column and studies the overall behavior, failure and ductility of the
strengthened column.
In the present experimental study, three RC columns, one ordinary column and
two strengthened columns with steel caging are subjected to constant axial load
which represents 55% of design axial load and reversed cyclic loading and their
performances are compared. The strengthened columns are designed for twice
the flexural capacity of the ordinary column. It is experimentally observed, that
the strengthened columns showed 1.98 and 2.42 times the flexural capacity of the
ordinary column and ductility by 2.43 and 3.18 times the ductility of ordinary
column. The confinement model predicted good results under the present
loading conditions.
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 楼主| wangjianping 发表于 2009-3-13 22:15:21 | 显示全部楼层
no.3  Control of Out of Plane Deformation of Inelastically Buckling Aluminium
Shear Panels
[Saiket Banerjee, October 2005, Supervised by Durgesh C. Rai]
Yielding of the shear panels can be used to dissipate energy through hysteresis
provided strength deterioration due to inelastic buckling is controlled. In the
present study, aluminium shear link with confined web panels were examined
experimentally under the application of cyclic lateral shear. Natural rubber block
along with steel plate were used for the purpose of confinement. Soft alloys of
aluminium are less susceptible to web buckling problems because of their low
yield strength which enables the usage of thicker webs. Widely available alloy
6063 and 1100 of aluminium for structural applications was used for fabrication
of the I-shaped specimens with transverse stiffeners from plates using TIG
welding process. Since this alloy was available in a harder temper, it was
annealed in order to reduce it to soften temper O and also to relieve residual
stresses developed due to welding. Six specimens of aluminium panels were
fabricated with different geometric parameters, like web thickness, spacing of
stiffeners and number of panels which affect the onset of inelastic buckling. All
the specimens were tested under pseudo-static reversed cycle loading with
increasing displacement levels using 500 kN servo-hydraulic actuator.
The specimens showed very ductile behaviour and excellent energy dissipation
potential with unpinched and full hysteresis loops with shear strains upto 0.2.
The confinement provided was effective in controlling the out-of-plane
deformation of the web panel, although the onset of inelastic buckling did not
improve much from that of the unconfined shear links. The experimental dataset
of confined and unconfined shear links was used to obtain the proportionality
factor in Gerard’s formulation of inelastic buckling. This result is further used to
obtain a relation between panel aspect ratio, the web panel depth-to-thickness
ratio, and web buckling deformation angle for cyclic inelastic buckling, which
can be used to determine the spacing of stiffeners.
Finally, eigenvalue buckling analysis and nonlinear static analysis of the
aluminium shear link model were done in finite element analysis programme
ABAQUS to verify the load deformation behaviour and the other aspects of
experimental study.
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 楼主| wangjianping 发表于 2009-3-13 22:16:06 | 显示全部楼层
no.4  Review of Blast Resistant Buildings and a Case Study of Library Building at
IIT Kanpur
[Lt. Col. Jasinder Singh Sodhi, June 2005, Supervised by Sudhir K. Jain]
The word “Terrorism” in today’s era has percolated in everybody’s life. It has
assumed a significant and dangerous dimension. The recent terrorist attacks the
world over have demonstrated that the public buildings and the common man
are as prone to such dangers as conventional security risk buildings. The most
potent weapon any terrorist uses is RDX or TNT. These names have become as
common as normal day to day words of English language.
Today no building is safe. Once conventionally regarded “soft targets” are being
used by the terrorists in a big way to cause damage and gain publicity.
Incorporation of certain blast resistant design features can reduce the damage to
human life and property. The success of adaptation of these blast resistant design
features would be quite evident when an engineer or an architect working at the
grass root level would imbibe them in planning and execution of his projects.
The existing Library Building at IIT Kanpur is an aesthetically designed building
which is partly on stilts. This building houses one of the most renowned
Libraries. Recently IIT Kanpur has been rated as the numero uno engineering
college of the country. It is highly probable that any terrorist organization might
try to cause a blast in this building to gain world wide attention.
This Thesis work comprises two parts, namely, enumeration of guidelines for
blast resistant buildings and study of the impact of blast loading on existing
Library Building at IIT Kanpur.
The Library Building was studied for blast loading using the software SAP 2000
Version 9.1.1. The blast load was modeled as a ramp function. On the basis of the
bending moments obtained in the members, the Demand Capacity Ratio was
calculated for two cases of blast loading and the impact of damage was assessed
and the building was found to be vulnerable under 31.75 kgs explosive in the
ground storey.
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 楼主| wangjianping 发表于 2009-3-13 22:16:40 | 显示全部楼层
no.5  Response of Buried Continuous Pipeline to Permanent Ground Deformation
[Suresh Ranjan Dash May 2005, Supervised by Sudhir K. Jain]
The response of continuous buried pipelines to lateral spreading is studied
mainly through the pipeline strain due to longitudinal and transverse PGD
(Permanent Ground Displacements). The existing approaches of analysis of
buried pipelines subjected to spatially distributed PGD are reviewed along with
their results. A continuous pipeline resting on ground and subjected to
transverse PGD and vertical settlement is modeled as a continuous beam resting
on non-linear soil springs(axial, lateral and vertical) using SAP2000 structural
analysis software. The responses so obtained are found to match reasonably well
with those from the previous finite element model studies. The results show that
the maximum strain induced in the pipeline is critically dependant on the width
over which the ground displacement occurred. In addition, the pipeline is
analyzed by both pseudo-static and dynamic analysis methods. The pseudostatic
analysis underestimates the peak pipe strain compared to the dynamic
analysis. Hence, for obtaining conservative force demands on the pipeline, the
dynamic analysis is preferable with detailed modeling.
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 楼主| wangjianping 发表于 2009-3-13 22:17:13 | 显示全部楼层
no.5  Response of Buried Continuous Pipeline to Permanent Ground Deformation
[Suresh Ranjan Dash May 2005, Supervised by Sudhir K. Jain]
The response of continuous buried pipelines to lateral spreading is studied
mainly through the pipeline strain due to longitudinal and transverse PGD
(Permanent Ground Displacements). The existing approaches of analysis of
buried pipelines subjected to spatially distributed PGD are reviewed along with
their results. A continuous pipeline resting on ground and subjected to
transverse PGD and vertical settlement is modeled as a continuous beam resting
on non-linear soil springs(axial, lateral and vertical) using SAP2000 structural
analysis software. The responses so obtained are found to match reasonably well
with those from the previous finite element model studies. The results show that
the maximum strain induced in the pipeline is critically dependant on the width
over which the ground displacement occurred. In addition, the pipeline is
analyzed by both pseudo-static and dynamic analysis methods. The pseudostatic
analysis underestimates the peak pipe strain compared to the dynamic
analysis. Hence, for obtaining conservative force demands on the pipeline, the
dynamic analysis is preferable with detailed modeling.
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 楼主| wangjianping 发表于 2009-3-13 22:17:50 | 显示全部楼层
no.6  Seismic Response of RC Frame Buildings on Stilts
[Perwez Ahmad, October 2004, Supervised by Sudhir K. Jain]
Two frames three-story one-bay and five-story tow-bay were designed for loads
corresponding to different zones as per Indian seismic code as well as for only
gravity loads in one case. Frames designed for seismic loads were detailed as per
ductile detailing code, else detailing was ordinary. Ground story columns of stilt
frames designed for zone III were redesigned for 2.5 times forces coming from
bare frame analysis. In the next case, first floor beams were also redesigned for
2.5 times forces. The masonry infill panels were modeled as equivalent diagonal
struts. Nonlinear pushover analysis was performed on bare, stilt and infill
frames. The performance of stilt frames were compared with bare and infill
frames in terms of strength, stiffness, deformation capacity, and overstrength
factor.
The study shows that deficit in ground story stiffness is 50-90% due to absence of
infills; while overall stiffness deficit is 25-65% and strength deficit is 10-70%.
Strength and stiffness deficit in ground story caused by absence of infills was
more prominent if ground story height is more, while it is less significant in the
frames designed for higher seismic zones. Both stilt frames in all design cases
collapsed due to failure of ground story columns. It implies that ground story
columns are more susceptible to failure than first floor beams in stilt frames.
Increase in overstrength factors due to infills was more significant in infill
frames compared to stilt frames. Overstrength factor due to infills was observed
to decrease in frames designed for higher seismic zones. Column-overstrength
factor decreases in higher seismic zones, as a result weak-column strong-beam
mechanism was more likely. Deformation capacity was considerably increased
due to ductile detailing in seismic design cases. In cases where, ground story
columns & first floor beams of stilt frames were redesigned for 2.5 times of bare
frame forces, an increase in stiffness and strength was noted; however, there was
a decrease in deformation capacity
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 楼主| wangjianping 发表于 2009-3-13 22:18:42 | 显示全部楼层
no.7  Forced Vibration Study of a Reinforced Concrete Building
[Lt. Col. Sanjay Adsar, September 2004, Supervised by Sudhir K. Jain]
Forced vibration tests are performed on a reinforced concrete (RC) moment
resisting frame (MRF) building with unreinforced masonry (URM) infill walls to
determine its dynamic properties namely, the fundamental translational and
torsional natural periods, the corresponding mode shapes and the structural
damping. This three-storey building lies in the seismic zone III of India. An
eccentric mass-shaker is used as force generator operating between 200 and 1400
cps, is used to apply a high level force and shake table for low level harmonic
force at desired frequencies.
The building is analytically modelled using the FEM package, ETABS. Three
models namely Bare frame model, Model with infill walls modelled as diagonal
struts without incorporating the effect of openings and Walls modelled as
diagonal struts after considering the effect openings struts. The dynamic
properties of the building as derived using these models are compared with the
experimentally obtained ones. The material properties used in the modelling, i.e.,
modulus of elasticity of brick masonry and reinforced concrete, are determined
by in-situ tests. It is found that the analytical model with infill walls modelled as
diagonal struts gave good correlation with the experimental results, whereas the
bare frame analytical model ignoring stiffness contribution of masonry walls
substantially overestimated the natural period in translational and torsional
modes of vibration.
It is observed that the high-level vibrations produced by the eccentric mass
shaker could excite the building fairly well thereby enabling better evaluation of
the dynamic properties as the vibrations were not influenced by an ambient
source of disturbance. Hence, this high force amplitude shaker can be very
effectively used to study the dynamic properties for a variety of structures in the
Indian subcontinent
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 楼主| wangjianping 发表于 2009-3-13 22:19:38 | 显示全部楼层
no.8   Experimental Investigation of Inelastic Cyclic Buckling of Aluminium Shear
Panels
[Sachin Jain, September 2004, Supervised by Durgesh C. Rai]
Yielding of the shear panels can be used to dissipate energy through hysterisis
provided strength deterioration due to inelastic buckling is controlled. In the
present study, cyclic inelastic buckling of aluminium panels in shear was
examined experimentally. Soft alloys of aluminium are less susceptible to web
buckling problems because of their low yield strength which enables the usage of
thicker webs. Widely available alloy 6063 of aluminium for structural
applications was used for fabrication of the I-shaped specimens with transverse
stiffeners from plates using TIG welding process. Since this alloy was available in
a harder temper T6, it was annealed in order to reduce it to softer temper O and
also to relieve residual stresses developed due to welding. Nineteen specimens of
aluminium panels were fabricated with different geometric parameters, like web
thickness, spacing of stiffeners and number of panels which affect the onset of
inelastic buckling. All the specimens were tested under pseudo-static reversed
cyclic loading with increasing displacement levels using 500 kN servo-hydraulic
actuator.
The tendency of buckling of the panel is delayed on increasing web depth-tothickness
ratio and reducing its aspect ratio. The specimens showed very ductile
behaviour and excellent energy dissipation potential with unpinched and full
hysterisis loops with shear strains upto 0.2. The experimental data set was used
to obtain the proportionality factor in Gerard's formulation of inelastic buckling.
This result is further used to obtain a relation between panel aspect ratio, the web
panel depth-to-thickness ratio, and web buckling deformation angle for cyclic
inelastic buckling, which can be used to determine the spacing of stiffeners,
which will limit the inelastic web buckling at design shear strains.
鲜花(60) 鸡蛋(0)
 楼主| wangjianping 发表于 2009-3-13 22:20:05 | 显示全部楼层
no.8   Experimental Investigation of Inelastic Cyclic Buckling of Aluminium Shear
Panels
[Sachin Jain, September 2004, Supervised by Durgesh C. Rai]
Yielding of the shear panels can be used to dissipate energy through hysterisis
provided strength deterioration due to inelastic buckling is controlled. In the
present study, cyclic inelastic buckling of aluminium panels in shear was
examined experimentally. Soft alloys of aluminium are less susceptible to web
buckling problems because of their low yield strength which enables the usage of
thicker webs. Widely available alloy 6063 of aluminium for structural
applications was used for fabrication of the I-shaped specimens with transverse
stiffeners from plates using TIG welding process. Since this alloy was available in
a harder temper T6, it was annealed in order to reduce it to softer temper O and
also to relieve residual stresses developed due to welding. Nineteen specimens of
aluminium panels were fabricated with different geometric parameters, like web
thickness, spacing of stiffeners and number of panels which affect the onset of
inelastic buckling. All the specimens were tested under pseudo-static reversed
cyclic loading with increasing displacement levels using 500 kN servo-hydraulic
actuator.
The tendency of buckling of the panel is delayed on increasing web depth-tothickness
ratio and reducing its aspect ratio. The specimens showed very ductile
behaviour and excellent energy dissipation potential with unpinched and full
hysterisis loops with shear strains upto 0.2. The experimental data set was used
to obtain the proportionality factor in Gerard's formulation of inelastic buckling.
This result is further used to obtain a relation between panel aspect ratio, the web
panel depth-to-thickness ratio, and web buckling deformation angle for cyclic
inelastic buckling, which can be used to determine the spacing of stiffeners,
which will limit the inelastic web buckling at design shear strains.
鲜花(60) 鸡蛋(0)
 楼主| wangjianping 发表于 2009-3-13 22:20:27 | 显示全部楼层
no.9  Effect of Soil Structure Interaction on Strength and Ductility Demands of
Shaft Supported Elevated Water Tanks for Earthquake Loads
[Bhumika Singh, May 2004, Supervised by Durgesh C. Rai]
Elevated water tanks supported on shaft-type stagings performed
unsatisfactorily in past earthquakes. Codes recognize the lack of redundancy,
overstrength and ductility in shaft-type stagings, and recommend larger design
forces. In this study, strength and ductility demands of shaft stagings of eight
tanks damaged during 2001 Bhuj (India) earthquake are re-assessed based on
elastic and inelastic analyses considering soil structure interaction and sloshing
motion of water inside the tank container. Shaft sections are found to fail at a
higher base shear when soil-structure interaction is considered, than their fixed
base counterparts. Also, ductility demands are less when soil-structure
interaction is accounted for. Further, failure mode of a shaft (i.e., flexure or shear)
depends on its aspect ratio and natural period of the tank. The study identifies
that shaft supported elevated water tanks designed considering (a) the effect of
soil-structure interaction, and (b) both flexure and shear capacities depending on
their aspect ratio, are likely to show improved performance during earthquakes
鲜花(60) 鸡蛋(0)
 楼主| wangjianping 发表于 2009-3-13 22:21:15 | 显示全部楼层
no.10  Design Spectrum-Based Scaling Of Strength Reduction Factors
[Debasis Karmakar, July 2003, Supervised by V. K. Gupta]
Strength reduction factors (SRFs) continue to play a key role in obtaining
inelastic spectra from elastic design spectra (through response reductions factors)
for ductility-based earthquake-resistant design. Despite several years of
sustained research efforts, it remains interesting to explore how best to estimate
these factors for a given design situation. This study proposes a new model to
estimate the strength reduction factor (SRF) spectrum, in terms of a pseudo
spectral acceleration (PSA) spectrum (normalized with respect to peak ground
acceleration, PGA) and ductility demand ratio, with the help of two coefficients.
The proposed model is illustrated for an elasto-plastic oscillator, in case of ten
recorded accelerograms and three ductility ratios. The proposed model is more
convenient to use in real-life applications and is able to predict SRF spectra
reasonably well, particularly at periods up to 1.0 sec. Its parameters may be
determined either by matching with the SRF spectrum for a single accelerogram
or from the SRF spectra for a suite of accelerograms that are compatible with the
same response spectrum. Those parameters are estimated in this study with the
help of 1274 accelerograms recorded in western U.S.A., in case of design spectra
for different combinations of earthquake magnitudes, site conditions and
epicentral distances. A parametric study is also carried out for the explicit
dependence of SRF spectra on strong motion duration, earthquake magnitude,
site conditions, and epicentral distance. The Trifunac-Brady definition of strong
motion duration is generalized for this purpose, and it is found that there is no
clear and significant dependence of SRF spectra on strong motion duration. The
parametric dependence on earthquake magnitude, site conditions, and epicentral
distance conforms to the trends reported by earlier investigations. In particular,
this study confirms that the dependence of SRF spectra on earthquake magnitude
should not be ignored.
鲜花(60) 鸡蛋(0)
 楼主| wangjianping 发表于 2009-3-13 22:21:56 | 显示全部楼层
no.11 A Statistical Study of Inelastic Displacement Ratio Spectrum For Existing
Structures
[Debasis Karmakar, July 2003, Supervised by V. K. Gupta]
Displacement-based design has been lately gaining importance due to the
emergence of the performance-based engineering, and it is now becoming
necessary to estimate maximum (inelastic) displacements of structures for
different levels of seismic hazard. Being closely related to damage, displacement
(or drift) has become an important parameter necessary to meet various
performance goals. It is considered convenient to estimate the inelastic
displacement demand in a structure by multiplying the elastic displacement
demand of the structure with a ratio called as the inelastic displacement ratio. A
comprehensive study has been conducted for the parametric dependence of the
inelastic displacement ratio in single-degree-of-freedom (SDOF) systems with
known relative lateral strengths, on strong motion duration, earthquake
magnitude, epicentral distance and geological site conditions. This study is more
rational than the earlier studies of similar type as other governing parameters
have been kept fixed while effects of variation in any particular parameter are
studied. This study is based on the generation of ensembles of synthetic
accelerograms from a database of 1274 accelerograms recorded in western U.S.A.
for pseudo spectral acceleration (PSA) spectra of given source and site
parameters. A new definition of strong motion duration has been proposed to
overcome the limitations of the existing definitions in the context of the present
study. It has been found that strong motion duration may influence the inelastic
displacement ratios, depending on the hysteretic properties of the oscillator, in
case of durations not much longer than 10 sec. Earthquake magnitude has a
significant influence on these ratios for the SDOF systems of most time-periods
while site conditions appear to be important for the stiff oscillators. A scaling
model has also been proposed in this study for estimating the inelastic
displacement ratio spectrum from normalized relative velocity spectrum of the
ground motion. This model indirectly includes the effects of various governing
parameters and has been shown to preserve the trends available from the direct
study.
鲜花(280) 鸡蛋(4)
ljmtidilgw 发表于 2009-3-14 05:11:11 | 显示全部楼层
Good, thanks prof

have a good weekend
鲜花(9) 鸡蛋(0)
waltdon 发表于 2012-10-3 09:12:01 | 显示全部楼层
专家,您好!看到你发的一个帖子帖名为dissertation summary of india iit kanpur 中有我比较喜欢也很重要的文件资料A Ductility And Displacement Based Design Procedure For Seismic Design ofReinforced Concrete Frames
可否有这个论文的完整版,发给我一下,谢谢您!我的邮箱 waltdon@163.com.
鲜花(0) 鸡蛋(0)
xyzxyz 发表于 2017-12-24 04:27:33 | 显示全部楼层
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