heal.abstract |
There are a lot of buildings in our country
designed and constructed before 1969,
namely before the first basic change of the Earthquake Code of 1959, which
essentially reflected the knowledge of the decade of 20’
-
30’.
What is contributed to
this was the absence of strong seismic events, such as tho
se which follow in the
coming decades that disclosed the weaknesses of the current regulations at that
time. The result of the intense reconstruction that prevailed during that decade was
the majority of buildings in Greece, especially in large urban cente
rs, to be consisted
of buildings of this type, which are seismic inadequate according to the new
Earthquake codes that were made our current decade.
In order for an intervention to be successful and effective, a good knowledge of the
expected behavior of t
he existing structure in a future strong earthquake is required.
So, there are many contemporary Codes, such as American FEMA, KANEPE, EC etc.,
moving in this direction and
aiming to designing and evaluating a structure according
to a performance level.
Th
e aim of this diploma thesis is the investigation of the behavior of a four
-
storey
reinforced concrete building against seismic loads, the assessment of the actual
strength it possesses, and the
amount that
the
infill
walls
participate in rising its
durabi
lity. It is a four
-
storey building constructed in 1960, dimensioned according to
the Reinforced Code of 1954 and the Earthquake Code of 1959.
The building is
mainly composed of columns, with shear walls in both the x and y directions.
Firstly, the building
was stressed by its own weight and a basic spectral analysis. The
floor
ς
were assumed to behave as diaphragms
.
Furthermore,
a seismic
excitation
was imposed by
mixing a variety of old earthquakes that took place in Greece
. These
were
applied to the buildi
ng
and the response was evaluated
. The pushover analysis
was carried out under conditions of constant gravity loads and monotonically
increasing horizontal loads
monitoring the displacement response of a particular
node at the top
4
th
storey. The analysis
software used was SAP2000.
After the
completion of the
above analysis, the
infill
walls were taken into account
in
the analysis of the multi
-
storey building
. Every wall, depending on the space
-
frame
ratio, was simulated with cross link sections, and a seco
nd pushover analysis was
applied
to the building.
In conclusion, the results of these two pushover
analyses
of the building with and
without the
infill
walls were compared
in order to understand the
ir
role
in
the
3
overall structural response
.
It became evident that up to damage control
performance level the structure with the infill walls demonstrate
d significant
increase in stiffness and strength, which though at higher performance levels tend to
diminish
approaching those of the bare skeleto
n structure |
en |