الفهرس 
Abstract
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Abstract
Sometimes it is necessary to create opening in concrete deep beams in order to
provide door openings, windows, ventilating ducts, or heating pipes. In existing RC
deep beams, such openings will produce discontinuities in the typical flow of
stresses, thereby reducing the shear capacity and rigidity of the beam. To
compensate for this reduction, such beams must be strengthened. This research
takes the rectangular opening reinforced concrete (RC) deep beam as the research
topic, and conduct numerical and experimental researches. The main objective of
the study is to recognize the influence of the size and location of openings in the
web on behavior of concrete deep beams and find solutions to strengthen such
beams to restore the requirements of the serviceability and ultimate limit states. The
study is carried out in two stages, one numerical and the other experimental. In the
numerical study, a set of factors such as the size of the openings and the concrete
strength were studied in order to determine the critical parameters for the
experimental study. In the experimental study, a group of reinforcement concrete
deep beams were implemented with different size and locations of openings. All
test beams were strengthened with steel plates with screws and epoxy materials to
determine effect of openings.
In the numerical study, the finite element model was created and executed using
ANSYS-software. The model was validated against experimental results from the
laboratory. Then, a parametric study was performed to recognize the effect of the
opening size on the behavior of deep beams of different concrete grades. The
opening location was located at the middle of the straight line between the load and
the support. The dimensions of the opening were changed in the vertical, horizontal,
and both directions. The concrete grade was ranged from the 25MPa to 80MPa.
In the experimental study, a total of 18 deep beams were constructed and
tested under four-point bending. All test specimens have a cross section of 150 x
700 mm with a total length of 1300 mm and concrete grade of 43 MPa. A reference
solid deep beam was designed according to (ACI 318-14) and (ECP 203-2018).
ii
Seven beams were tested with opening in one side of the beam, i.e. the side hinged
support. A square opening with dimension 150x150mm interrupted the natural load
path. The location of the opening was once in the top, middle, and bottom of the
line connecting the load to the hinge support. Two openings of the same dimensions
were also chosen so that they were located on the same line between the load and
the hinge support. As a result of the numerical study, a large opening was chosen
with dimensions of 200 x 400. In an attempt to reduce the impact of the opening on
the deep beams, additional seven beams with the same dimensions and opening
details were constructed in the lab. After curing time, steel sheets were used to
envelop the expected load paths around the opening to strengthen the test beams.
Generally, the structural response of RC deep beams with rectangular openings
mainly depends on the opening intersection with the natural load path. The increase
of the opening height has the greatest impact on the shear strength of the deep
beam. The increase in the grade of concrete with the same cross-sectional area of
the tie leads to changes the failure mode of the beam. On the other side, the results
of the experimental study showed that the opening in the middle of the line between
the load and the support has the least effect on the shear strength of the deep beam.
The overlap between the openings near the support and the support itself caused the
confined zone between the opening and the support to damage, which led to the
rapid collapse of the beam. Increasing the area between the two load paths around
the opening leads to a significant decrease in the shear resistance of the deep beam.
The study found that the externally bonded steel sheet around the load paths was
very effective in improving the performance of RC deep beams under the service
loads.
Finally, a numerical study was carried out to find another method to strengthen
these beams as extension of the experimental study. The installation of a steel jacket
in the tension zone of the concrete deep beams was a very effective solution for
strengthening such beams.