IRJET - Experimental Investigation of flexural member of Beam Opening in web by using PVC pipe

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 07 Issue: 03 | Mar 2020 www.irjet.net p-ISSN: 2395-0072
© 2020, IRJET | Impact Factor value: 7.34 | ISO 9001:2008 Certified Journal | Page 3737
Experimental Investigation of Flexural Member of Beam Opening in
Web by using PVC Pipe
Stefee.S.R1, C. Ravi2
1PG Scholar, Structural Engineering, Oxford Engineering College, Trichy, Tamil Nadu, India.
2Assistant Professor, Department of Civil Engineering, Oxford Engineering College, Trichy, Tamil Nadu, India.
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Abstract - Now a days, in many construction industryfaced
by the problem is shortage of raw materials. So, we are the
responsibility to reduce the effects of application of concrete
materials to environmental impacts. In normally a beam has
two zone that is compression zone and tension zone. For
compression zone at top and tension zone at bottom of the
beam. In compression zone is strong in concrete and tension
zone is week in concrete therefore in tension zone some
quantity of concrete is removed and inserted PVC pipes at
certain diameter. This paper presents the details of flexural
behavior of opening in beam for laterally and longitudinally
direction. The experimental investigation consist of casting
and testing of RC beams of size 1000mm x 200mm x 150mm
with and without opening in tension side. Here, beams are
tested by one point loading and two point loading. The
performance of opening core of beams under flexuralstrength
shows better than conventional solid beam.
Key Words: Hollow core Reinforced concrete beam, light
weight, web opening, flexural behaviour etc.
1. INTRODUCTION
In natural concrete behaviour,it’sstrongincompressionand
week in tension. For my assumption to design the R.Cbeams
in tensile stress of concrete to be neglected. So, it reduce
alternative use of concrete. In reinforced concrete beam, at
above neutral axis has less stressed and at the belowneutral
axis has serves a shear transmitting media. Here the bond
between PVC pipes and concrete layer at the concrete pipe
should be very good. In reinforced concrete beams with
hollow natural axis shows the stresses in beams are
maximum at top and bottom and zero at neutral axis. So,
cheap and light weight material is used at the near neutral
zone. For this we can saves the cement and also reduces the
greenhouse gases emissions and it considered as the
environmental friendly.
1.1 Web Opening in beam
Beams with opening near the center stub showed similar
crack pattern. Generally, the flexural cracks are appeared
ahead of shear crack but this pattern is reversed in beam
openings. If opening size is increased, loads that cause
diagonal cracks and cracks width will decline.
Moreover, crack width is larger in beams with openings
than solid beams and exceed limitations of crack width
irrespective of location and size of holes. From this, it
becomes quite clear that serviceability of cracks could
extremely influenced by openings. For increasing opening
sizes and changing their locations from the Centre stub of
beam were obviously decreases the ultimate strength of the
beams. When the openings were located close to the beam
supports to skip failure plane, the ultimate strength
decreases when compared with beams without openings by
more than ten percent. This resulted from cutting one or
more stirrups which decrease capacity to carry considerable
amount of applied shear.
Figure 1: Normal beam detailing and web opening in
latteral direction
2. OBJECTIVE OF THE WORK
The main objective is to reduce the usage of concrete and
also to introduce new method of reinforced concrete beam
by using PVC pipes at below the neutral axis in longitudinal
and lateral direction without affecting the geometry of the
section.
3. METHODOLOGY
The methodology of project work consist of
(1) Selecting the grade of concrete – M30
(2) Mix design for M30 grade concrete.
(3) Using this mix proportion RC solid beam and RC
hollow beam with neutral and below neutral axis
were cast.
(4) By conducting flexural test various effects of these
beams were studied.

4. MATERIAL TEST
Table -1: Material Testing Results
TEST MATERIAL
EQUIBMENTS
USED
VALU
ES
Specific gravity OPC 53 grade Le Chatelier
flask
3.15
Specific gravity
Fine aggregate
(M – sand)
Pycnometer 2.64
Specific gravity
Coarse aggregate
( 20 mm size)
Wire basket
2.76
Workability
M30 grade
Slump cone
apparatus
100
mm
5. MIX DESIGN
Table -2: Mix proportion for M30 grade of concrete
Cement (Kg/m3) 438.2
Fine aggregate (Kg/m3) 651.5
Coarse aggregate (Kg/m3) 1160
Water (li/m3) 197.2
Water cement ratio 0.45
Mix 1 : 1.49 : 2.65
6. EXPERIMENTAL INVESTIGATION
A. Details of beams
In this research 14 beams were castedat thesizeof1000mm
x 200 mm x 150 mm and 50mm dia PVC pipes were used.
Two control beam (CB), six beam with hollow core at neutral
axis for longitudinal and lateral direction and six beam with
hollow core at below neutral axis for longitudinal and lateral
direction are cured at 28 days. For longitudinal direction, 3
numbers of 250 mm length PVC pipes placed in Zigzag
pattern and lateral direction, 15 numbers of 90mm length
placed in Zigzag pattern. All beams aredesignedasperIS456
– 2000. In this beam 3 numbers of 12mm dia is used at
tension zone and 2 number of 10mm dia is used at
compressionzoneandshearreinforcement8mmdiastirrups
@ 100mm c/c spacing. Main acceptsforthisresearchflexural
strength, center span deformation and strain behavior of
beam were examined.
Depth of neutral axis can be calculated by considering M30
grade concrete and Fe415 steel with an effective cover
25mm.
As per IS 456 – 2000 code,
Depth of neutral axis at limiting value,
Xu,max/d = 0.46
Xu,max = 0.46 x 175
= 80.5mm
Tension reinforcement,
Ptlim = 41.61 (fck/fy)(xu,max/d)
Ptlim = 1.38 %
100Ast/b x d = 1.38
Ast = 362.25 mm2
Area of steel rft = 3 * (Π x 122/4)
= 339.29 mm2
Depth of neutral axis,
X u = (0.87 x 415 x 339.29)/ (0.36 x 30 x 150)
= 75.61 mm
Therefore, X u < Xu, max
Hence, the section is under reinforced section.
Minimum shear reinforcement 8mm dia @ 100 mm spacing
PVC PIPES
NA
Figure 2: Schematic sectional plan of specimen in
longitudinal zigzag position.
PVC PIPES
NA
Figure 3: Schematic sectional plan of specimen in lateral
zigzag position.
Figure 4: Arrangement of PVC pipes in longitudinal zigzag
position.
Figure 5: Arrangement of PVC pipes in longitudinal zigzag
position.

Figure 6: Casted specimen in longitudinal and horizontal
zigzag position
B.Test procedure
The flexural strength of the testing specimen were tested by
100T loading frame and also dial gauge were used for
determining the deflection of the beam. In this research, one
point and two point loading were used to test the specimen.
The behaviour of thebeamswasobservedfromthebeginning
to failure of the specimen. The first crack appearance, the
development and the propagation of cracks due to the
increase of load were noted. After that the loading was
continued at the initial cracks and was stopped when the
specimen was just on the verge of collapse.Here load was
applied by hydraulic jack. Then thevaluesofloadappliedand
the deflection of specimen were noted directly and also plot
the graph between load and deflection which is taken as the
output. The applied load increased up to the breaking point
or till the failure of the specimen.
Figure 7: Experimental set up of beam in one point
loading
7. EXPERIMENTAL RESULTS
A. Load carrying capacity.
The comparison of the results between the solid control
beam and the beam with PVC pipes below and at the neutral
axis as shown in fig. and fig. In this research the specimens
were denoted as solid controlbeam(CB1 andCB2),beamwith
hollowneutralaxisatlongitudinalzigzagposition(BLO1),and
beam with hollow below neutral axis at the depth of 100 mm
in longitudinal zigzag position (BLO2), beam with hollow
below neutral axis at the depth of 125 mm in longitudinal
zigzag position (BLO3) and beam with hollow neutral axis at
lateral zigzag position (BLA1), and beam with hollow below
neutral axis at the depth of 100 mm in lateral zigzag position
(BLA2), beam with hollow below neutral axis at the depth of
125 mm in lateral zigzag position (BLA3)
Chart 1: Ultimate load of beam in longitudinal zigzag
position
Chart 2: Ultimate load of beam in lateral zigzag position
B. Load and Deflection
When the load increases the deflection of beam begins. The
corresponding deflection of CB ,beam with hollow neutral
axis and the load up to a safe 150 KN given in Table 3 and
Table 4.
Table -3: Load and deflection of beam for one point load.
Load (KN)
Deflection (mm)
CB1 BLO1 BLO2 BLO3
10 0.22 0.18 0.16 0.19
20 0.29 0.21 0.19 0.27
30 0.45 0.41 0.28 0.79
40 0.58 0.55 0.34 0.90
50 0.69 0.63 0.46 1.11
60 0.74 0.69 0.55 1.34
70 0.95 0.88 0.69 1.45
80 1.15 0.99 0.78 1.69
90 1.28 1.10 0.95 1.88
100 1.58 1.29 1.18 2.19
110 1.79 1.49 1.37 2.55
120 2.37 1.84 1.79 2.98
130 2.88 2.19 2.00 3.09
140 3.18 2.53 2.38 3.75
150 3.88 2.97 2.74 3.98

Table -4: Load and deflection of beam for two point
loading.
C.Saving of concrete and self-weight reduction.
Concrete is one of the most important building material. For
construction site, huge amount of concrete wastage can
occurs. Material cost is a main component in the total cost of
the product varying from 25 to 70 % therefore, in order to
the cost control, it is necessary to paythemaximumattention
for controlling material cost especially throughtheabnormal
losses.
In this research, dimension of beam is 1000 mm x 200 mm x
150 mm and PVC pipes length 250mm and dia 50mm for
longitudinal zigzag directionandPVCpipeslength90mmand
dia 50mm for lateral zigzag direction,
By calculating the volume, we know the % of reduction in
concrete volume.
Volume of specimen (beam) V1 = 1000 x 200 x150
= 3 x 107 mm3
Volume of PVC pipe V2 = Πr2l
= 3.14 x 252 x 250 x 3
= 1471875 mm3
% Reduction in concrete (longitudinal) = [(V2/V1)] x 100
= 5 %
Self-weight reduction,
All structural and architectural components shall have dead
load weight and also self-weight which are permanent in
nature. If we reduce the volume of concrete then self-weight
of the beam also get reduced.
Unit weight of concrete = 25 KN/m3
Weight of 1 m3 concrete = 2500 kg.
Volume of specimen (beam) V1 = 1 x 0.2x0.15
= 0.03 m3
Weight of beam, W1 = 2500 x 0.03
= 75 kg
Consider, PVC pipe dimension
Volume of PVC pipe V2 = Πr2l
= 3.14 x 0.0252 x 0.75
= 1.4 x 10 -5 m3
Weight of concrete saved, W2 = 1.4 x 10 -5 x 2500
= 0.036 kg
Weight of hollow core beam = 74.964 kg
For small beam, self – weight reduction is also small. When
assuming large beam, weight reduction will be larger.
8. CONCLUSIONS
In this experimental research forwebopeningRCbeams and
test result obtained.
1. Flexural behaviour of the RC beam with web
opening is similar to the conventional RC beam.
2. The optimum depth of web opening at the below
neutral axis is 100mm (from top).
3. The strength were increased in RC beam for web
opening in lateral zigzag direction when compared
to longitudinal zigzag direction.
4. As comparing with one point loading test, the two
point loading test is better.
5. Economy and reduction of weight of specimens is
depends on the % of replacement of concrete. The
concrete saving will be more effective as the length
and depth increases.
6. Web opening reinforced concrete beamcanbeused
for sustainable and environment friendly
construction work and its saves concrete which
reduces the emission of CO2 during the production
of cement.
REFERENCES
1. D. Abhale R.B., Kandekar S.B. and Satpute M.B.
(2016), ‘PVC Confining Effect on Axially Loaded
Column’, International Journal of Emerging
Technologies in Engineering Research (ISSN:2454-
6410), Vol-2, pp.54 -60.
2. Bilna Pappachan (2017), ‘ Review on shear
strengthening of RC deep beams with openings’,
International Journal of Emerging Technologies in
Engineering Research ( ISSN: 2454-6410), Vol 5,
Issue 8, pp.63 - 69.
Load (KN)
Deflection (mm)
CB1 BLO1 BLO2 BLO3
10 0.19 0.11 0.11 0.15
20 0.29 0.22 0.14 0.3
30 0.41 0.39 0.18 0.75
40 0.52 0.45 0.24 0.89
50 0.64 0.53 0.36 1.1
60 0.7 0.67 0.45 1.24
70 0.85 0.82 0.59 1.35
80 1.10 0.91 0.71 1.65
90 1.25 1.00 0.89 1.85
100 1.52 1.21 1.1 2.10
110 1.76 1.39 1.32 2.45
120 2.30 1.78 1.69 2.88
130 2.78 2.10 1.98 3.06
140 3.12 2.43 2.18 3.45
150 3.68 2.78 2.54 3.89

3. Dipti R. Sahoo , Carles A. Flores and Shih-Ho Chao.
(2012), ‘Behaviour of Steel Fiber-Reinforced
Concrete Deep Beams with Large Opening’, ACI
Structural Journal, Vol. 109, No. 2, pp.193 - 204.
4. Gopi . N and Sujitha .B. (2017), ‘ Behaviour of
Concrete Filled PVC Plastic Tubes (CFPT) Placed In
Columns’, International Conference on Emerging
trends in Engineering, Science and Sustainable
Technology(E-ISSN: 2348 – 8352) , Vol-3, pp.6 – 8.
5. Geetha . H. and Swedha .T ( 2015 ) ‘An Experimental
study on Concrete Filled Tubular Columns Using
Varying Steel Materials’ , International Journal of
Innovative Science, Engineering & Technology, Vol.
2 Issue 5, Vol-4, pp.737-742.
6. Heba A. Mohamed (2013), ‘Effect of Web Openings
size on Steel fiber Reinforced Concrete Deep
Beams’, International Journal of current
Engineering and Technology (ISSN 2277 – 4106) ,
Vol – 3, pp.1230 – 1237.
7. N.G. Kin mun, (2015), ‘Strengthening of reinforced
concrete deep beams having large square openings
in shear zone with carbon fiber reinforced polymer
(CFRP)’, International Journal of Advanced
Engineering Research and Studies (E-ISSN2249–
8974) , Vol-2 , pp.66 -68.
8. Khalaf Ibrahem Mohammad, (2007) ‘Prediction of
Behaviour of Reinforced Concrete Deep Beam with
Web openings using finite elements’, Al-Rafidain
Engineering ,Vol.15, No.4 , pp. 1-12.
9. M.A. Mansur, (2006) ‘Design of Reinforcedconcrete
beams with web openings’, 6th Asia-Pacific
Structural Engineering and Construction
Conference (APSEC), Vol – 5, pp.104 – 120.

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