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International Journal of Civil Engineering and Technology (IJCIET) Volume 10, Issue 01, January 2019, pp. 651-663, Article ID: IJCIET_10_01_059
Available online at http://www.iaeme.com/ijciet/issues.asp?JType=IJCIET&VType=10&IType=01
ISSN Print: 0976-6308 and ISSN Online: 0976-6316
© IAEME Publication Scopus Indexed
SHEAR REINFORCEMENT EFFECTS ON THE
FLEXURAL STRENGTH OF REINFORCED
CONCRETE BEAMS
Ameer A. N. Al-jamel and Hayder M.K. Al-Mutairee
Civil Engineering, University of Babylon, Iraq
ABSTRACT
This research devotes to conduct an investigation into the effects of lateral
reinforcement on the flexural behaviour of Straight Reinforced Concrete Beam
(SRCB). The amount of both longitudinal and lateral reinforcement, beam aspect ratio
(h/d) and shear span of concentrated load to depth ratio (a/d), are considered. The
experimental work includes casting and testing of fifteen SRCB of normal strength with
simple ends. The beams divided into three groups according to h/b ratio which taken
equal to (1.5, 2, and 2.5). The experimental results show that for SRCB with h/b equal
to 2 and under concentrated load at mid-span the ultimate load carrying capacity
increased by (30.8%, and 22.23%) when increasing the shear reinforcement by (50%,
and 100%) respectively. Also, the ultimate strength was increased by about 10.38%
and 16.53% with increment in shear reinforcement of 50%, and 100% respectively for
beams with h/b equal to 1.5 and under two-point load at third point. Finally, the results
appear not only increments in the capacity of ultimate load and decrement in the cracks
width when decreasing the shear reinforcement spacing but also the ductility of the
beams has increased observable.
Key words: Reinforced concrete, beams, shear reinforcement, Confinement of
flexural reinforcement, ductility
Cite this Article: Ameer A. N. Al-jamel and Hayder M.K. Al-Mutairee, Shear
Reinforcement Effects on the Flexural Strength of Reinforced Concrete Beams.
International Journal of Civil Engineering and Technology, 10(01), 2019, pp. 651–663
http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=10&IType=01
1. INTRODUCTION
The lateral reinforcement in reinforced concrete structures provides shear resistance, keeps the
longitudinal reinforcement in place during concreting, prevents the compression reinforcement
from buckling and confines the concrete in the core. The present study is concerned with the
effect of confinement due to lateral reinforcement (in particular) upon the strength and
deformation characteristics of beams.
Ameer A. N. Al-jamel and Hayder M.K. Al-Mutairee
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Flexural yield strength defined as the stresses in the materials just before their yields. When
a material is subjected to bending, just the fibres at extraordinary edge are at the biggest stress
in this way, when those fibres are free from any deformities, the flexural strength can be
controlled by those fibres. However, if the similar material was just under tensile forces then
every one of the fibres in the material have a similar stress and the failure will start when the
weakest fibre achieves its greatest tensile stress. Thus, for a similar material, the flexural
strengths will be higher than tensile strengths. On the other hand, a homogeneous material that
has deformities on its surfaces may have a higher tensile strength than flexural strength.
In a simply supported beam subjected to bending, the fibres are in compression above the
neutral axis, whereas in tension below this axis. The factors affecting on shear strength and
formation of inclined cracks are so many and complicated that a final conclusion concerning
the accurate mechanism of inclined cracking developed from high shear is difficult to
determine. The shear behavior of reinforced concrete beams at failure is decidedly different
from their flexure behavior. They fail suddenly without enough advanced caution, and the
diagonal cracks that grow are greatly larger than the flexural cracks. [1] Discussed the effects
of lateral reinforcement upon the strength and deformation properties of concrete and found
that lateral reinforcement improves the strength and ductility of confined concrete, and has a
detrimental effect upon the cover. [2] Presented equation for shear strength of reinforced
concrete beams that has enough simplicity expressed by concrete strength, reinforcement ratio
and effective depth in accumulative form. The results appeared that a part of the shear force
can be transferred by the dowel action of longitudinal bars. It is found that the main factors
influence on this action was flexural rigidities of the bars, and strength and rigidity of the
surrounding concrete. [3] Showed that the structural size effect may be illuminated by
considering structures of different sizes and fixed other variables. They concluded that the size
effect was considered for diagonal shear failure of reinforced beams and one-way slabs without
shear reinforcement. [4] Tested reinforced high-strength concrete beams designed to fail by
shear. It was concluded that for beams without shear reinforcement, the failure shear strength
generally increased as the concrete compressive strength increased. Beams with equal amount
of transverse reinforcement, the higher concrete compressive strength gives the more effectual
stirrups. [5] Exhibited a few aftereffects of test examination on six fortified solid pillars in
which their auxiliary conduct in shear was considered. The examination directed about the
utilization of extra even and autonomous twisted up bars to build the shaft opposition against
shear powers. From trial examination, the utilization of twisted up and free flat bars as shear
support were more grounded than ordinary shear fortification framework. [6] Talked about the
aftereffects of exploratory inquire about conducted to study the concept that the convincing
significance is not has effect on the shear nature of fortified bond flexural individuals which
did not contain shear reinforcement. It was found that flexural and flexure-shear cracks were
influenced importantly by the shear strength. [7] Tried examples had indistinguishable
longitudinal reinforcement, however changing shear fortification proportions to examine the
impacts of shear limit on the effect conduct. The results show that the shear qualities of the
examples assumed a vital job in their general conduct. Examples with higher shear limit could
manage more effects and retain more vitality, though the ones with bring down shear limit
endured broad harm under the same or littler effect loads. [8] Showed behavior of shear
cracking of simply supported reinforced concrete beams. The width of shear crack was
increased proportionally with both the spacing of shear cracks and with the strain of shear
reinforcement. It was detected that the larger spacing of stirrups gives larger width of shear
crack. [9] Tested reinforced concrete simply supported beams with different shear
reinforcement; welded swimmer bars, bolted swimmer bars, u-link bolted swimmer bars, and
traditional stirrups. The results showed that there is change in shear quality of fortified solid
Shear Reinforcement Effects on the Flexural Strength of Reinforced Concrete Beams
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bars by utilizing swimmer bars all in all. Likewise, the length and width of the splits were less
using swimmer bars contrasted with the conventional stirrups framework. [10] Tested
reinforced concrete simply supported beams without stirrups. They proved that the shear span
to depth ratio (a/d ) has an important effect on the shear strength both at low and high values
of a/d. [11] tested simply supported beams with compressive strength of concrete was equal to
29 MPa and the shear span to depth ratio was equal to three. The study demonstrates that the
commitment of shear reinforcement to the shear limit is vital and straightforwardly relative to
the amount and spacing of the web reinforcement. The study showed that the adequacy of the
shear reinforcement diminishing with expanding the spacing of shear reinforcement along the
beam width. Shear strength was more effective for wide beam with high tensile stress in the
steel. Additionally, results demonstrate that the ductility of the wide beams importantly
improves by the web reinforcement. [12] Showed arching action behavior of beams. It was
concluded that where the point of confinement of the compressive bend is more important than
that given by the steel fortress, the longitudinal strengthening extent has only a minor effect on
the zenith stacking cut off of the at the edge-controlled RC columns. In like manner, it was
exhibited that gave the base essentials to staying away from delicate shear frustration are met,
and the part is under-sustained, the withdrew suppression given by transverse help gave
through the plastic pivot length has only a minor effect on the zenith stacking cut-off of RC
shafts that make colossal calculating movement. [13] studied the distribution of longitudinal
reinforcements of reinforced concrete horizontally curved beams with fixed-ends. He
concluded that the non-uniform distribution of longitudinal reinforcements is effective and can
be used to improve the strength of beams, and it is important when the angle of horizontal
curvature of the beam is increased. [14] Studied the effects of yield strength of steel,
compressive strength of concrete, thickness of slab and the bar diameter used in edge-supported
two-way slabs. The results showed where (fc') increases from 15 to 35MPa the (As) will be
decreased by (13%) when ( ���
�≈ 3.5
�
��) and for any values of other variables, also it is not
economical to use high strength of concrete when the term (���
�) between (0.5-1 kN/mm). Also,
the study proved that when the thickness (t) increases to (50%), the (As) will decreases (28%
to 32% according to the parameter), while; if the thickness of slab increases to (100%), the
(As) will decreases (62% to 64%). [15] Showed that the shear span to depth ratio a/d represents
the main parameter that has importantly effect on the shear strength in straight reinforced
concrete beams without shear reinforcement. In most researches the effect of web
reinforcement on the flexural strength of beams was disregard. The recommendations of those
researches and some of the previous investigations are based on the premise that the main
function of lateral reinforcement is to prevent the compression reinforcement from buckling
and to confine the core concrete, rather than the effect of web reinforcement on the flexural
strength of beam.[16] tested ten specimens of reinforced concrete continuous deep beams
(RCCDB) under two-point loads. The effects of high strength concrete (HSC) layer thickness
and Carbon Fibre Reinforced Polymer (CFRP) on the strength of RCCDB were thus studied.
The results showed that the strengthening of RCCDB by an HSC layer at the top is better than
that from one at the bottom, as the increments in ultimate load strength were 17% and 34% for
top strengthening and 8% and 26% for bottom strengthening for 25% and 50% thickness of
total depth of beam, respectively. The optimal strengthening of RCCDB using an HSC layer at
the top was at 50%.
2. MATERIALS AND METHODS
Ameer A. N. Al-jamel and Hayder M.K. Al-Mutairee
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In this research fifteen beams tested, they are divided into three groups according to the h/b
ratio.
The details of samples geometry and reinforcement are tabulated in Table 1.
Table 1: Section geometry and reinforcement details of tested samples
Bea
m N
ame
Dim
ensi
on
(mm
) Longitudinal Reinforcement Shear Reinforcement
Ratio of �
�
�
ℎ Number of bars
at bottom
�����.
����
%
Spacing
(cm)
∅5@ Incr
emen
t
%
B11 h=240
b=160
h/b=1.5
5∅9.98
90
9 0
0.67 2.78 B12 6 50
B13 4.5 100
B21 h=320
b=160
h/b=2
3∅9.98
+3∅4.65 47
14 0
0.67 2.08 B22 9.33 50
B23 7 100
B24 h=320
b=160
h/b=2
6∅9.98
+2∅4.65 84
12 0
1 3.13 B25 8 50
B26 6 100
B27 h=320
b=160
h/b=2
7∅9.98
+1∅4.65 97
10 0
1 3.13 B28 6.67 50
B29 5 100
B31 h=300
b=120
h/b=2.5
3∅9.98
+2∅4.65 61
13 0
0.67 2.22 B32 8.67 50
B33 6.5 100
2.1. Materials properties
Reinforcement: Two different diameters of reinforcements are used (∅4.65 and ∅9.98) and
tested according to ASTM-A615/A-615M-05a. The yield stress was (561 and 573MPa)
respectively.
The mechanical properties of hardened concrete: The compressive strength test determined
as decided by (BS.1881: Part 116:1989) [17] and (ASTM C33, 2008) [18]. The results of cubes
were converged and the average strength of them was 35MPa. Also the Modulus of Rupture
test performed by concrete prisms specimens with dimensions (100×100×400) mm were cast
as decided by (ASTM C78, 2004) [19] procedure. The average of all specimens was 3.4MPa.
The properties of the other materials are described in Appendix A. Section reinforcement: All
beam sections designed according to the (ACI-Code 2014) [20] requirement for bending and
shear, but the flexural failure mode secured to study the effects of stirrups on the flexural
behavior of beam. The compression zone was reinforced by two bars of ∅9.98mm, while the
shear reinforcement has a diameter bar of ∅4.65mm. Figure (1) and Figure (2) show the
geometry and load scheme of specimens. Each group has the same amount of h/b but the shear
reinforcement increase by 50% and 100% as shown in figures (3) to (7).
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All dimensions in mm
Figure. 1: Geometry of specimens of group one and three and branch one of group two (B21, B22,
and B23)
All dimensions in mm
Figure. 2: Geometry of specimens of branch two and three of group two (B24, B25, B26, B27, B28,
and B29).
Figure 3: Section details of specimens of first group.
Figure 4: Section details of specimens of branch one of second group
Figure 5: Section details of specimens of branch two of second group.
Figure 6: Section details of specimens of branch three of second group.
Ameer A. N. Al-jamel and Hayder M.K. Al-Mutairee
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Figure 7: Section details of specimens of third group.
Trials mixes: In order to obtain the required properties of the concrete, three trial mixes
were experimentally conducted and one of these mixes was adopted. The procedure of the trial
mixes was by select different water/cement ratio (0.52, 0.54, and 0.56). The fresh concrete was
then examined to evaluate its validity (workability, and segregation). For the chosen mix; six
cubes and six prisms were cast to estimate the mechanical properties of hardened. The adopted
mix proportions of concrete are tabulated in Table 2.
Table 2: Mix proportion of concrete
Materials Proportions Units
Cement 342 kg/m3
Coarse
aggregate 1011 kg/m3
Fine
aggregate 748 kg/m3
Water 192 kg/m3
W/C ratio 0.56 ----
Forms Manufacturing: Fifteen set of plywood formworks made. Plywood blocks were
used to obtain smooth surfaces. The formwork and reinforcement cage are shown in Fig.8.
Figure 8: Reinforcing cages and wooden formworks
Casting of the samples: Before the casting, the forms were greased and the steel cage
installed in place by using 15 mm spacers, the top pieces of the form were then fastening to
brace the cage in place and prevented it from rising up because of its flotation ability due to the
presence of vibrator. The specimens were done using 2 m3 mixture in a one day by central
mixer for quality control. The concrete was poured directly into the form as shown in Fig.9.
The casting was including six 150×150×150 mm cube and six 100×100×400 mm prism was
poured along the casting period. The curing process was done using two tanks contain the
samples, cubes and prisms. The curing water was changed every 7 days then after 28 days the
samples were got out from the container and prepared to test.
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Figure 9: Casting process.
Testing Procedure: All beams were tested in a universal testing machine as shown in Fig.
10. The beams were simply supported over a span of 2000 mm rested on solid steel frame. The
test of beams was under static load, and loaded in successive increments until failure. The
specimens painted in white colour before testing in order to observe crack development. The
deflection readings of dial gauge at mid-span and cracks width were recorded at selected levels
of loading. In addition, the cracks were detected and drawn on the side face of the tested beams.
Dial gage for measuring deflection of the beam specimens at mid-span with accuracy of 0.01
mm. Mechanical strain gage was using to measure the concrete strain with accuracy of 0.002
mm.
Figure 10: Specimen in universal testing machine.
3. RESULS AND DISCUSSIONS
3.1. First cracking load
Crack formation was monitored at different loading stages. Beams of first group which has h/b
ratio is equal to 1.5 and under two-point load showed better enhancement in first cracking loads
when shear reinforcement was increasing. Beams of first branch of the second group (where
was under two-point load with moment to shear ratio of 0.667) which had h/b ratio is equal to
2 showed good enhancement in first cracking loads compared with the other two branches
which was under one mid-span concentrated load with moment to shear ratio of 1. Beams of
third group which has h/b ratio is equal to 2.5 and under two-point load had first cracking loads
close to each other. Table 3 contains the details of the first cracking load of the specimens. Table 3: Experimental results of specimens
Gro
up
No.
Bea
m n
ame First crack
Ultimate load (kN) Increase in ultimate load
(%) Pcr
(kN)
Crack width
(mm)
1 B11 69 0.10 141.6 0
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B12 78 0.09 156.3 10.38
B13 82 0.07 165 16.53
2
B21 55 0.08 169 0
B22 59 0.06 163.5 -3.25
B23 62 0.04 172.6 2.13
B24 31 0.06 154.6 0
B25 42 0.03 170.7 10.41
B26 39 0.02 191.2 23.67
B27 33 0.03 164.6 0
B28 27 0.03 215.3 30.80
B29 32 0.03 201.2 22.23
3
B31 39 0.03 142.5 0
B32 40.5 0.03 149 4.56
B33 40 0.02 140.5 -1.40
Table 4: Experimental results of specimens
Group No. Beam name Load at yield
Defl.
at yield
(mm)
Decreme -nt % Max.
Defl. (mm) Ductility
1
B11 105 11.27 --- 28 2.48
B12 105 10.60 5.94 31 2.92
B13 105 8.38 25.64 37.1 4.43
2
B21 145 9.87 --- 22.53 2.28
B22 145 10.14 -2.74 21.32 2.10
B23 145 9.11 7.70 23.10 2.54
B24 145 10.02 --- 20.60 2.06
B25 145 7.34 13.62 22.65 3.09
B26 145 7.17 28.44 25.41 3.54
B27 160 10.78 --- 17.06 1.58
B28 160 8.01 25.70 24.55 3.06
B29 160 9.67 10.30 21.74 2.25
3
B31 130 11.32 --- 18.75 1.66
B32 130 10.36 8.48 23.55 2.27
B33 130 11.61 -2.56 23.43 2.02
3.2. Crack width
In the present investigation, the splits were estimated by utilizing the break meter. The
arrangement of first split was checked all through the test to record the width of this break with
expanding load near failure of the beam models. The connection among load and break width
for the three gatherings is appeared in Figures 11 to 14.
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Load against midspan deflection: Two dial gages were placed at mid-span to measure the
deflection. Generally, it can be observed that the load versus mid-span deflection response can
be divided into three stages of behavior. The first stage was characterized by an approximately
linear relationship, during this stage of behavior, the section was uncracked and both the
concrete and steel behave essentially elastic. The second stage represents the behavior beyond
the initial cracking of the section where the stiffness of the beam was decreased as indicated
by the reduced slope of the load versus mid-span deflection curve. The end of this stage was
distinguished when the main steel reinforcement starts to exhibit inelastic behavior. The third
stage was characterized by a decreasing slope of the curve, where the tension steel
reinforcement reaches the strain hardening stage. The experimental load versus mid span
deflection for these models is shown in Figures (16) to (20).
Ameer A. N. Al-jamel and Hayder M.K. Al-Mutairee
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Ultimate Load and Failure Modes: All examples were tried up to failure. The recorded
extreme burdens and failure methods of the shaft’s examples are introduced in Table 5. Table 5: failure mode of specimens
Group No. Specimen Failure mode
1
B11 Concrete Cover Separation
B12 Concrete Cover Separation
B13 Concrete Cover Separation
2
B21 Typical flexural failure
B22 Typical flexural failure
B23 Concrete Cover Separation
B24 Typical flexural failure
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B25 Typical flexural failure
B26 Typical flexural failure
B27 Typical flexural failure
B28 Typical flexural failure
B29 Typical flexural failure
3
B31 Typical flexural failure
B32 Concrete Cover Separation
B33 Concrete Cover Separation
4. CONCLUSION
Depending on the experimental results taken from the laboratory tests the following
conclusions were made:
1. The measure of restriction given by lateral reinforcement is needy upon the
separating of horizontal reinforcement as well as on the appropriation and
proportion of flexural reinforcement and the nature of limited concrete.
2. Spacing of lateral reinforcement is the most important parameter, because the
choice of bar sizes, and the qualities of concrete and steel are limited in practice.
The effect of transverse reinforcement decreases drastically with increasing the
spacing.
3. Depending upon the arrangement of shear reinforcement and the relative areas of
core and cover the presence of shear reinforcement appears to improve the over-all
ductility of the members.
4. Beams with h/b equal to 1.5 with high percent of !"#$%./!�'( (which equal to 90%)
have increment in the ultimate load carrying capacity by (10.38% and 16.52%)
whenever shear reinforcement increased by (50%, and 100%) respectively, while
the beams with h/b equal to 2 with high percent of !"#$%./!�'( (which equal to
97%) have high increasing in the ultimate load by (30.8%, and 22.23%) when the
shear reinforcement increasing by (50%, and 100%) respectively.
5. Beams with !"#$%./!�'( equal to 47% and 61% have very small increment and
decrement in the ultimate load.
6. There is enhancement in the cracking behavior for all beams that have an increment
in the shear reinforcement where the crack width was decreasing with increasing in
its number.
7. Before the yield point, the deflection was decreasing with increasing load by
25.64% and 28.44% with !"#$%./!�'( equal to 90% and 84% respectively when the
increment in the shear reinforcement was by 100%.
8. After the yield point, the deflection was increasing with increasing load and thus
the ductility of beams was increasing by 4.43 and 3.54 with !"#$%./!�'( equal to
90% and 84% respectively when the increment in the shear reinforcement was by
100%.
REFERENCES
[1] M. Sargin, S. K. Ghosh, and V. Handa, "Effects of lateral reinforcement upon the strength
and deformation properties of concrete," Magazine of concrete research, vol. 23, pp. 99-
110, 1971.
Ameer A. N. Al-jamel and Hayder M.K. Al-Mutairee
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[2] H. Okamura and T. Higai, "Proposed design equation for shear strength of reinforced
concrete beams without web reinforcement," in Proceedings of the Japan Society of Civil
Engineers, 1980, pp. 131-141.
[3] Z. P. Bazant and J.-K. Kim, "Size effect in shear failure of longitudinally reinforced
beams," Journal of the American Concrete Institute, vol. 81, pp. 456-468, 1984.
[4] A. Cladera and A. Mari, "Shear design procedure for reinforced normal and high-strength
concrete beams using artificial neural networks. Part II: beams with stirrups," Engineering
structures, vol. 26, pp. 927-936, 2004.
[5] A. Hamid and N. Azlina, "The use of horizontal and inclined bars as shear reinforcement,"
Universiti Teknologi Malaysia, 2005.
[6] L. H. Sneed and J. A. Ramirez, "Effect of depth on the shear strength of concrete beams
without shear reinforcement–experimental study," 2008.
[7] S. Saatci and F. J. Vecchio, "Effects of shear mechanisms on impact behavior of reinforced
concrete beams," 2009.
[8] M. Zakaria, T. Ueda, Z. Wu, and L. Meng, "Experimental investigation on shear cracking
behavior in reinforced concrete beams with shear reinforcement," Journal of Advanced
Concrete Technology, vol. 7, pp. 79-96, 2009.
[9] M. M. Al-Nasra and N. M. Asha, "Shear reinforcements in the reinforced concrete beams,"
American Journal of Engineering Research (AJER), vol. 2, pp. 191-199, 2013.
[10] M. N. Khaja and E. G. Sherwood, "Does the shear strength of reinforced concrete beams
and slabs depend upon the flexural reinforcement ratio or the reinforcement strain?,"
Canadian Journal of Civil Engineering, vol. 40, pp. 1068-1081, 2013.
[11] M. Said and T. Elrakib, "Enhancement of shear strength and ductility for reinforced
concrete wide beams due to web reinforcement," HBRC Journal, vol. 9, pp. 235-242, 2013.
[12] N. FarhangVesali, H. Valipour, B. Samali, and S. Foster, "Development of arching action
in longitudinally-restrained reinforced concrete beams," Construction and Building
Materials, vol. 47, pp. 7-19, 2013.
[13] H. M. K. Al-Mutairee, "Effect of Non-Uniform Distribution of Longitudinal Reinforcement
on the Behavior of Reinforced Concrete Horizontally Curved Beams with Fixed-Ends,"
Journal of University of Babylon, vol. 21, pp. 826-838, 2013.
[14] F. F. AL-Himdani, N. Hasson, and H. F. H. AL-Abosi, "THE EFFECT OF WEIGHT
DISTRIBUTION ON THE REQUIRED STEERING TRACK-FORCES IN TRACKED
VEHICLES," Journal of Engineering and Sustainable Development, vol. 17, pp. 300-316,
2013.
[15] M. Słowik, "Shear failure mechanism in concrete beams," Procedia Materials Science, vol.
3, pp. 1977-1982, 2014.
[16] H. Al-Mutairee and H. Al-Hamdani, "Shear behaviours of hybrid continuous deep beams
strengthened with carbon fibre reinforced polymer," in IOP Conference Series: Materials
Science and Engineering, 2018, p. 012027.
[17] B. British Standard, "part 116, 1983," Method for determination of compressive strength
of concrete cubes," British Standards Institution, 1881.
[18] A. S. f. Testing, M. C. C.-o. Concrete, and C. Aggregates, Standard test method for
resistance of concrete to rapid freezing and thawing: ASTM International, 2008.
[19] ASTM C78/C78M-10, Standard Test Method for Flexural Strength of Concrete, Annual
Book of ASTM Standards, American Society for Testing and Materials, Philadelphia, 2004.
[20] A. Committee, "Building code requirements for structural concrete (ACI 318M-14) and
commentary (ACI 318RM-14)," 2014.
Shear Reinforcement Effects on the Flexural Strength of Reinforced Concrete Beams
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APPENDIX A:
Materials properties:
Cement: Ordinary Portland cement (Type I) was used in casting of the beams. This cement
was manufactured by united cement company, commercially known (Crista). The properties
are conformed to the Iraqi specification limits [8] for ordinary Portland cement.
Fine aggregate: Regular sand from (Al-Akaidur) area was utilized as fine total. The degree
of the fine total exists in the upper and lower limits of Iraqi Specification [7] Zone (2) and [3]
specification.
Coarse aggregate: Squashed coarse total from (Badra and Jassan's quarry) was utilized
with greatest total size 19 mm. The rock was washed and cleaned by water, at that point dried
before utilizing. The strainer investigation of coarse total exists in the upper and lower limits
of Iraqi specification [7] and [3] specification.
Water: Ordinary clean tap water used in this work for both mixing and curing of the
specimens.
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