Engineering and Technology Journal

This study presents an experimental and nonlinear finite element analysis of creating square openings in existing RC beams and strengthening with CFRP laminate. Flexural strengthening of reinforced concrete beams is now becoming more and more important in the field of structural maintenance and retrofitting. In the experimental programming, three RC beams were cast. Two beams were tested in the un-strengthened condition the first act as the solid Control beam, and the other have openings, the third one have opening and strengthening with CFRP laminate. The beams were also modeled using a FEM packaged (ANSYS 11). The results indicate that the strengthened beam recorded the highest failure load and its mode of failure was ductile. The numerical results seemed to be able to predict the behavior of the beams.

In this paper some results from previous experimental test are adopted
and analyzed using a nonlinear three-dimensional finite element ANSYS
computer program (v.11) to investigate the effect of the presence of
horizontal construction joints (H.C.J.) on the behavior of reinforced
concrete (RC) beams.
Three beams having one, two and three (H.C.J.) that divide the beam into equal
parts, as well as one reference beam without a joint were analyzed. The results
obtained from the finite element analysis show very good agreement with the
results obtained from the previous experimental test. The maximum differences in
ultimate loads were about (8.2-10.4)% for all types of tested beams. The presence
of one, two and three (H.C.J.) in RC beams under flexure gave a decrease in the
value of the cracking load such that Pcr was (97%), (85%) and (80%) of (Bref).
The respective ultimate load capacity Pu was (96%), (89%) and (84%) compared
to (Bref).

This research study involves experimental and theoretical investigations of the
behavior of flexural debonding of carbon fiber reinforced polymer (CFRP) laminates
with steel anchorages. A total of nine reinforced concrete beam specimens with cross
section of (150mm width by 250mm height and 2000mm length) were investigated in
this study to observe the flexural strength of each one. Eight beam specimens were
strengthened with CFRP laminates and one beam specimen was tested without
strengthening. The experimental results showed that the use of CFRP strips as external
strengthening has significant positive effect on ultimate loads, crack patterns and
deflections. The percent of increasing of the ultimate load capacity can be increased by
about 65% when using two layers of CFRP strips instead of one layer. The ultimate
load is increased by about 118% for the beams strengthened with bonded CFRP and
external anchorage with respect to the reference beam. Three-dimensional nonlinear
finite element analysis (i.e. ANSYS - version 9.0 computer program ) is used to
investigate the performance of reinforced concrete beams strengthened with CFRP.
The comparison between the numerical and the experimental results asserted that good
validity of the numerical analysis and the methodology developed in this study.