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determinedenchiladaΠολεοδομικά Έργα

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

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UNIVERSITY OF BAGHDA
D

/ COLLEGE OF ENGINEERING


CIVIL ENGINEERING

DEPARTMENT




Title

Nonlinear Behavior of Reinforced Concrete Rectangular Columns with
(PVC) Embedded Pipes

Student

Ali Hussein Ali Al
-
Ahmed


Supervisor

Prof. Dr. Thamir K. Mahmoud and Dr. Raad K.
Shukur

Publishing
Year

20
1
0

Abstract


In this research the behavior of reinforced concrete columns with embedded PVC
pipes under axial compressive load and uniaxial bending was studied. The experimental
part of this research includes testing of ten columns of dimensions (150

150

800 mm).
Test parameters were the pipe size (i.e, hollow ratio of 4.00%, 8.11%, 12.78% and
18.70%) and the load eccentricity, (eccentricity/ column depth ratio of 0.267 and 0.667).

Nonlinear finite element analysis has been car
ried out using ANSYS computer
program to simulate the behavior of reinforced concrete columns with embedded PVC
pipes. Material nonlinearity due to cracking and crushing of the concrete, tension
stiffening and shear retention effect of cracked concrete and

yielding of reinforcing bars
were considered. The nonlinear equations of equilibrium have been solved using an
incremental
-
iterative technique operating under arc
-
length control procedure.

To verify the experimental and finite element results at the ultim
ate state, column
cross sections have been analyzed at this state. The equilibrium and compatibility
equations have been set up following the ACI 318M
-
08 Code. Two additional computer
programs have been coded for calculating the nominal strength capacity f
or reinforced
concrete columns with circular opening and to develop the interaction charts for these
columns.

Good agreement has been found among the experimental, finite element and
section analysis results. For a range of hollow ratio of (4.00%
-

18.70%)

and for
eccentricity ratio of 0.267, the experimental, finite element and the section analysis
results indicate ranges of strength reduction of (2.69%
-

11.00%), (2.91%
-

10.68%) and
(2.51%
-

10.32%) respectively. While for eccentricity ratio of 0.667, no

considerable
reduction in strength was occurred.

For the (4%) hollow ratio in columns as permitted by the ACI
-
Code, the
experimental, finite element and section analysis results indicate an upper bound
reduction in the ultimate load of about 3% for a rang
e of eccentricity of e/h (0.267


0.667).

The finite element results indicate that all the PVC pipes embedded in the
reinforced concrete columns of the test program did not reach its permissible stress even
at the ultimate state of the column.

The first cr
acking load and the ductility index have been obtained for each test
column and the influence of hollow ratios and eccentricities on results have been
obtained. Interaction design charts for reinforced concrete columns with embedded pipes
relating the ulti
mate axial load and bending moment have been established
.

UNIVERSITY OF BAGHDA
D

/ COLLEGE OF ENGINEERING


CIVIL ENGINEERING

DEPARTMENT