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25 Νοε 2013 (πριν από 3 χρόνια και 8 μήνες)

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Prof. Sarosh H Lodi

NED University of Engineering and Technology

What Works and Does not Work in the
Science and Social Science of

Earthquake Vulnerability
,

January 28
-
29, 2011


Most

of

the

buildings

in

the

urban

areas

are

semi



engineered

non
-
ductile

reinforced

concrete

moment

resistant

framed

structures

with

very

stiff

masonry

walls

but

not

designed

and

detailed

to

resist

seismic

forces
.



Most

of

the

buildings

in

the

rural

areas

are

non



engineered

load

bearing

stone/

brick

masonry

structures

with

no

resistance

to

seismic

forces
.

INRTODUCTION

Typical Urban Buildings

Typical Urban Buildings

Typical Urban Buildings

Model 1

Model of infill to increase seismic
resistance a cost effective solution

COMPARISON OF BARE FRAME AND
INFILL FRAME

MATERIAL PROPERTIES

GEOMETRIC PROPERTIES

f’c

=

21

MPa

fy

=

415

MPa

F
cm

=

2
.
1

MPa




PARAMETERS USED FOR ANALYSIS

BARE

FRAME

FRAME WITH INFILL

Soil

profile

type

=SD

C
t

=

0
.
03

(For

moment

resisting

frame)

R

=

5
.
5

Zone

=

2
B

Soil

profile

type

=

SD

C
t

=

0
.
02

(For

all

other

building

system)

R

=

5
.
5

Zone

=

2
B



MODELING PARAMETERS OF INFILL
(STRUTS)

a = Depth of strut



t = Width of strut

t
c

= Thickness of shortcrete


E
c

= Modulus of Elasticity of shortcrete

E
m

= Modulus of Elasticity of infill

E
fe

= Modulus of Elasticity of frame

h
col

= Depth of column


I
c

= Moment of inertia of column

h
inf

= Height of infill



L
diag

= Diagonal length of infill

q =

Inclination angle of infill

For retrofitted strut:

For ordinary strut in above equation use:

E
c

= 0 and t
c

= 0



STRENGTH OF INFILL (STRUTS)

For Compression strut:

For Tension tie:

TIME PERIOD AND BASE SHEAR

FOR BARE FRAME

FOR INFILL FRAME

COMPARATIVE ANALYSIS OF STRENGTH BASED
ON PERFORMANCE BASED ANALYSIS


FAILURE MECHANISM

BARE

FRAME

FOR INFILL FRAME

COMPARATIVE ANALYSIS OF STOREY
DISPLACEMENTS

Model 2

Addition of strength to the infill to
increase seismic resistance

RETROFITTED MODELS

a)
BY MAKING STRONGER COLUMN AND BEAM WHICH
ARE TO BE FAILED IN PREVIOUS ANALYSIS


i.
RCC OR STEEL JACKETING OF COLUMNS

ii.
RCC OR STEEL JACKETING OF BEAMS


b)
BY INTRODUCING A SPINE

RETROFITTED MODELS

Retrofitted columns and
beams with infill

Retrofitted Elements

Retrofitted Elements

8 “
th

RCC wall & 4”
th

shortcrete

with 6”c/c steel

6” thick
shortcrete

with 8”
c/c steel


3” thick
shortcrete

with
8”c/c steel


2” thick
shortcrete

with
12”c/c steel


Retrofitted infill wall

COMPARATIVE ANALYSIS OF STRENGTH OF
RETROFITTED MODEL

FAILURE MECHANISM OF RETROFITTED MODELS

Retrofitted columns and
beams with infill

Retrofitted infill wall

COMPARATIVE ANALYSIS OF STOREY
DISPLACEMENTS

Campaign

Typical Rural Buildings

Typical Rural Buildings

Typical Construction

INTRODUCTION


School buildings are vital for a society


They are places of learning


They also play a significant role in the relief
operation in post
-
disaster situations.


These buildings can be used as temporary shelters.


Assessment of seismic vulnerability of school
buildings is essential to ensure safety of children
and teachers.

DESCRIPTION OF SCHOOL


School
consists of 4 classrooms.


These have been divided into 3 blocks.


Load resisting system consists of cavity walls of stone
rubble masonry.


These provide resistance against gravity loads.


Roofing

system consists is of timber trusses and
corrugated metal sheeting
.


Construction

inherently lacks resistance to lateral
loads.

PLAN OF SCHOOL

VIEW OF SCHOOL



A view of school is shown in figure below.

TYPICAL SECTION OF WALL

Typical wall section of the construction in the area is shown
in figure below.

X

Y

Z

ANALYTICAL MODELLING



A mathematical model of the school was developed.


Finite Element Program SAP was employed.


Individual blocks were modelled as solid brick elements.


Mortar was modelled using non
-
linear springs.


Non
-
linear properties of mortar were defined using existing
constitutive models.


Geometric non
-

linearity were also taken into account.


Ground shakings were simulated using El
-
Centro ground
accelerations

ANALYTICAL MODELLING



Axial behaviour is modelled as follows

ANALYTICAL MODELLING



Shear behaviour is modelled as follows

ANALYSIS OF RETROFITTED SCHOOL


A view of the mathematical retrofitted model is shown
in figure below

ANALYSIS OF RETROFITTED SCHOOL



A view of retrofitted long wall is presented in figure
below which shows the jacketing scheme around the
openings.

ANALYSIS OF RETROFITTED SCHOOL



A view of retrofitted short wall is shown in figure below
which displays a typical wall without openings.

PROGRESS IN RETROFITING WORK

PROGRESS IN RETROFITING WORK

PROGRESS IN RETROFITING WORK

STRUCTURAL RETROFITTING OF
GGPS NAYASHER # 3

PROGRESS IN RETROFITING WORK

STRUCTURAL RETROFITTING OF
GGPS NAYASHER # 3

PROGRESS IN RETROFITING WORK

STRUCTURAL RETROFITTING OF
GGPS NAYASHER # 3

PROGRESS IN RETROFITING WORK

STRUCTURAL RETROFITTING OF
GGPS NAYASHER # 3

PROGRESS IN RETROFITING WORK

STRUCTURAL RETROFITTING OF
GGPS NAYASHER # 3

PROGRESS IN RETROFITING WORK

STRUCTURAL RETROFITTING OF
GGPS NAYASHER # 3

PROGRESS IN RETROFITING WORK

STRUCTURAL RETROFITTING OF
GGPS NAYASHER # 3

Thanks!