International Journal of Engineering Trends and Technology (IJETT) – Volume 28 Number 8 - October 2015
Finite Element Analysis of Beam Column Joint with GFRP under
Dynamic Loading
Shabana T S #1, Dr. K.A Abubaker*2, Renny Varghees#3
#
1(M.Tech Student, Civil Department, Ilahia college of Engineering & Technology/ M G University, India)
*
2(Structural engineering consultant, Kochi, India)
#
3(Assistant Professor, Civil Department, Ilahia college of Engineering & Technology/ M G University, India)
Abstract — In the Bhuj Earth quake in Gujarat, the main
reason for the failure of most of the structures was the failure
of the beam column joints. Hence it is essential to strengthen
the existing structures, especially the beam column joints. The
details of finite element analysis of beam column joints
wrapped with glass fibre reinforced polymer sheets (GFRP)
carried out using the package ANSYS are presented in this
paper. So here First model and analyse G+4 office building
using ETABS. Beam column joints were manually designed on
the basis of both IS456:2000 and IS13920:1993 by using
structural data available from ETABS. Four exterior
reinforced concrete beam column joint specimens were
modelled using ANSYS package. The first specimen had
reinforcement as per code IS 456:2000. The second specimen
had reinforcement as per code IS 13920:1993. The third
specimen had reinforcement as per code IS 456:2000 and was
wrapped with GFRP sheets. The fourth specimen had
reinforcement as per code IS 13920:1993 and was wrapped
with GFRP sheets. During the analysis both the ends of
column were hinged. Static load was applied at the free end of
the cantilever beam up to a controlled load. The efficiency of
confining the reinforced beam column joints with GFRP sheet
wrapped at the beam column joint under dynamic loading and
the results are presented in this paper. The percentage of
increase in efficiency of wrapped over unwrapped is found to
be 37% for beam column joint designed as per IS 456:2000
and 20% for designed as per IS 13920:1993.
Keywords — Finite Element Modelling, Behaviour, RCC
Beam Column Joints Retrofitted With GFRP Sheets, Ansys.
exterior joints under dynamic loading.
I. INTRODUCTION
In RC buildings, portions of columns that are common to
beams at their intersections are called beam-column joints. In
beam column joints, the beam and column members are
particularly vulnerable to failures during earthquakes. A new
technique has emerged recently which uses fiber reinforced
polymer (FRP) sheet to strengthen the beam column joint. The
techniques of using fiber sheets give an advantage such as
ease to install, immunity to corrosion and high strength.
During the present investigation, ANSYS modelling of
reinforced concrete beam column joints has been carried out
to understand the behaviour GFRP sheet wrapped at the
III. METHODOLOGY OF WORK.
First of all, considered an office building (3x3 bay frame).
Then the structural modelling can be done by using ETABS.
Manual designing of beam and column can be done on the
basis of both IS456-2000 and IS13920-1993 by using
structural data available from ETABS. Detailing can be done
using Auto Cad 2013, and then all beam column joint needs to
be modelled using ANSYS package.
ISSN: 2231-5381
II. LITERATURE REVIEW
N. Ganesan, P.V. Indira and Ruby Abraham(2007), This
paper describes the experimental results of ten steel fibre
reinforced high performance concrete (SFRHPC) exterior
beam-column joints under cyclic loading . The results were
evaluated with respect to strength, ductility and stiffness
degradation. [1]. Mrs. S. M. Kulkarni and DR. Y.D.
Patil(2012), This paper present review on reinforced concrete
beam-column joints. Initial experimental studies were done in
early sixties, only in the last few years the research has
intensified. [2]. A.G. Kay Dora and N.H. Abdul Hamid
(2012), This paper present Seismic performance of full-scale
precast beam-column end joint with corbel mixed up together
with SFRC. Precast beam-column joint has low ductility and
prone to severe damage when subjected to bigger drift due to
lateral loading [3]. S. S. Patil, S. S. Manekari (2013), This
paper deals with the study of beam column joint applying
monotonic loading on cantilever end of the beam. Study of
various parameters corner and exterior beam column joint can
be analysed in ANSYS software [4]. T. Subramani,
S.Krishnan, M.S.Saravanan, Suboth Thomas (2014), The
Finite element method (FEM) has become a staple for
predicting and simulating the physical behaviour of complex
engineering systems. The details of the finite element analysis
of beam column joints retrofitted with carbon fibre reinforced
polymer sheets (CFRP) carried out using the package ANSYS
are presented in this paper [5].
Here four exterior beam column joint specimens want to be
modelled using Ansys package.
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International Journal of Engineering Trends and Technology (IJETT) – Volume 28 Number 8 - October 2015
1.
The specimen is to be modelled as per code IS
456-2000
2. The specimen is to be modelled as per code IS
13920-1993
3. The specimen is to be modelled as per code IS
456-2000 and is wrapped with GFRP
4. The specimen is to be modelled as per code IS
13920-1993 and is wrapped with GFRP
Reinforcement is used to model the beam column joint in
ANSYS. In order to model GFRP wrapping, the properties
of GFRP wrapping is incorporated to the software
The results so obtained are comparing and find out the
efficiency of GFRP in both designs.
IV. DESIGN OF BEAM COLUMN JOINT
A. Problem definition
• A ground plus four Storey RC office building is considered.
• Plan dimensions: 8 m x 8 m
• Location considered: Zone-III
• Soil Type considered: Rock Soil
B. General Data of Building:
Grade of concrete : M 20
Grade of steel considered : Fe 250, Fe 415
Live load on roof: 2 KN/m2 (Nil for earthquake)
Live load on floors : 4 KN/m2
Roof finish : 1.0 KN/m2
Floor finish : 1.0 KN/m2
Brick wall in both direction : 240 mm thick
Beam in longitudinal direction : 240X300 mm
Beam in transverse direction : 240X300 mm
Column size : 240X360 mm
Density of concrete : 25 KN/m3
Density of brick wall including plaster : 20 KN/m3
Thickness of slab : 120mm
1. Summury of design as per IS 456-2000
C4 - column portion was reinforced with 4 numbers of
16mm diameter fe415 rods.
Latral ties in the column 8mm diameter fe 250 bars
240mm c/c spacing.
2. Summuryof design as per IS 13920-1993
C4 - column portion was reinforced with 4 numbers of
16mm diameter fe415 rods.
Latral ties 8 mm diameter bars at a spacing of 80 mm for
a height of 350mm on either side. Remining portion
spacing of 120mm.
D. Design of beam (B6)
Data available from ETAB:
Factored Bending Moment, Mu ( negative )= 30.062 kNm
Factored Bending Moment, Mu ( positive )= 18.862 kNm
Factored Shear Force, Vu = 37.83 kN
1. Summury of design as per IS 456-2000
B6 - beam portion was reinforced with 2 numbers of
16mm diameter fe415 rods at top and 2 numbers of
12mm diameter fe415 rods at bottom.
Vertical stirrup in the beam 6mm diameter fe 250
bars 190mm c/c spacing.
2. Summury of design as per IS 13920-1993
B6 - beam portion was reinforced with 2 numbers of
16mm diameter fe415 rods at top and 2 numbers of
12mm diameter fe415 rods at bottom. Vertical
stirrup
6mm diameter two legged stirrups at a
spacing of 60mm up to distance of 520mm from the
face of the column. Remining portion for a spacing
of 120mm.
E. Anhorage length
According to IS 456:2000, cl 26.2, the calculated tension
or compression in any bar at any section shall be
developed on each side of the section by an appropriate
development length or end anchorage or by a
combination. The development length Ld is given in cls
26.2.1 as
Ld =
Fig. 1. Exterior beam column joint to be designed (modelled in ETABS)
C. Design of column(C4)
Data available from ETAB:
Factored load, Pu = 251.61 kN
Factored moment in X direction, Mux = 4.11 kNm
Factored moment in Y direction, Muy = 17.467 kNm
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Where,
ϕ= nominal diameter of the bar,
= stress in bar at the
section considered at design load
= design bond stress
given in cl 26.2.1.1 of IS 456:2000
Anchorage length of tension rod =48ϕ =768mm
Anchorage length of compression rod =48ϕ =576mm
According to IS 13920:1993, clause 6.2.5, in an external
joint, both the top and the bottom bars of the beam shall
be provided with anchorage length, beyond the inner face
of the column, equal to the development length in tension
plus 10 times the bar diameter minus the allowance for 90
degree bend. In an internal joint, both face bars of the
beam shall be taken continuously through the column.
Anchorage length of tension rod = 888mm
Anchorage length of compression rod = 696mm
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International Journal of Engineering Trends and Technology (IJETT) – Volume 28 Number 8 - October 2015
Fig. 1 Reinforcement Details as per IS 456:2000
Fig. 3 Reinforcement Details as per IS 13920:1993
B. Modelling dimension of joint: By taking advantage of the
symmetry of the beam column joint, a quarter of the full
beam column joint was used for modelling. This approach
reduced computational time and computer disk space
requirements significantly. 5mm thick GFRP plate can be
used for wrapping purpose.
C. Steel plate: A 20 mm thick steel plate, modelled using
Solid185 elements, was added at the loaded location in
order to avoid stress concentration problems. This
provided a more even stress distribution over the loaded
area.
D. Boundary condition: During analysis both ends of
columns are hinged. Modelling of the boundary conditions
is often the most critical aspect in achieving sensible,
reliable data from a finite element model. In the test
specimens, the critical zones (around the joint) were far
from the applied boundary constraints (edge of the
model).Accurate boundary constraints however, still
required. The column connections were modelled as
hinged supports attached to a single node to allow full
rotation. Column end caps, used to support and restrain the
test specimens in the loading frame, were included in the
model to allow the effective length of the column to be
modelled correctly. The material for the end caps had a
higher ultimate capacity, but had a similar stiffness to the
concrete to reduce restraint in the adjacent elements.
E. Loading condition: The static load was applied at the free
end of the cantilever beam at a regular load interval of
5 kN for the unwrapped and wrapped reinforced concrete
beam column joint models. A transverse static was applied
at the free end of the beam to develop a bending moment
at the joint. The load was increased in steps till a
controlled load of 20 kN. The deflection at the free end of
the cantilever beam was noted.
F. Element used:
Solid65 was used to model the concrete. The solid element
has eight nodes with three degrees of freedom at each node –
translations in the nodal x, y, and z directions. The element is
capable of plastic deformation, cracking in three orthogonal
directions, and crushing. Ex = 22360.6 N/mm2, PRXY=0.2
and Tensile cracking strength =3.13. The geometry and node
locations for this element type are shown in below
V. FINITE ELEMENT MODELLING
Meshing was done for exterior beam column joint using
ANSYS. Both ends of the column were hinged. The concrete
was modelled using Solid 65 element. The reinforcement was
modelled using Link180 element. The wrapping was modelled
using Solid 185 element. The static load was applied at the free
end of the cantilever beam at a regular load interval of 5 kN for
the unwrapped and wrapped reinforced concrete beam column
joint models. The performance of the wrapped beam column
joint specimen was compared with the beam column joint
Fig.4.Solid65 – 3-D Reinforced Concrete Solid
specimens without GFRP.
A
Link180
element is used to model the steel reinforcement.
A. Finite element modelling: Discrete method was applied in
Two
nodes
are
required for this element. Each node has three
the modelling of the reinforcement and stirrups used in the
degrees
of
freedom,
– translations in the nodal x, y, and z
tested specimen. The two elements were connecting at the
directions.
As
in
a
pin-jointed
structure, no bending of the
adjacent nodes of the concrete solid element, such that the
element is considered. Plasticity, creep, rotation, large
two materials shared the same nodes.
deflection, and large strain capabilities are included. Ex
=
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International Journal of Engineering Trends and Technology (IJETT) – Volume 28 Number 8 - October 2015
2.1×105 N/mm2 and PRXY = 0.3. The geometry and node
locations for this element type are shown in Figure below
Fig.5.Link 180
Solid 186 is used modelling of GFRP. It is a higher order 3-D
20-node solid element that exhibits quadratic displacement
behaviour. The element is defined by 20 nodes having three
degrees of freedom per node: translations in the nodal x, y,
and z directions. The element supports plasticity, hyper
elasticity, creep, stress stiffening, large deflection, and large
strain capabilities. It also has mixed formulation capability for
simulating deformations of nearly incompressible elasto
plastic materials, and fully incompressible hyperplastic
materials. Ex = 22×103 N/mm2 and PRXY = 0.28
Fig.8. Meshing of exterior beam column joint without GFRP and with GFRP
using ANSYS
Fig.6.Solid 186
Solid185 is used for modelling of steel plate. It is defined by
eight nodes having three degrees of freedom at each node:
translations in the nodal x, y, and z directions. The element
has plasticity, hyper elasticity, stress stiffening, creep, large
deflection, and large strain capabilities.Ex = 2.1×105 N/mm2
and PRXY = 0.3
Fig.9. Detailing of the specimen as per IS 456:2000
Fig.7.Solid 185
Fig.10. Detailing of the specimen as per IS 13920:1993
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International Journal of Engineering Trends and Technology (IJETT) – Volume 28 Number 8 - October 2015
VI. DISCUSSION OF RESULT
Fig.13.Load-deflection graph (IS 456:2000 and IS 13920: 1993(without
GFRP))
Fig.11. A typical deflection diagram for load of 5kN.10kN, 15kN and 20kN
(beam column joint without GFRP)
Figure 13 shows the difference of load versus displacement
curves between design of beam column joint as per
IS456:2000 and IS 13920: 1993modelling. The difference
between the two different modelling methods is clear. The
model (designed as per IS13920: 1993) yields displacement of
1.739 mm for a load of 20kN, corresponding for IS456:2000
is 2.48mm.
By comparing specimen for 20 kN load, 30% deflection
lower in beam column joint designed as per IS 13920: 1993
than IS456:2000.
B. Comparing the deflection values of beam column joint
designed as per is 456:2000 without GFRP and with GFRP
Fig.12. A typical deflection diagram for load of 5kN.10kN, 15kN and 20kN
(beam column joint with GFRP)
TABLE1
DEFLECTION VALUES OF BEAM COLUMN JOINT
External joint
IS456 :2000
(without
GFRP)
IS13920: 1993
(without
GFRP)
IS456 : 2000
(with GFRP)
IS13920: 1993
(with GFRP)
Deflection in mm for a load
5kN
10 kN
15 kN
20 kN
0.35
0.915
1.65
2.48
0.14
0.59
1.13
1.739
0.13
0.501
0.928
1.5623
0.0588
0.3481
0.7351
1.3935
A. Comparing the deflection values of beam column joint
designed as per is 456:2000 and is 13920: 1993(without
GFRP)
ISSN: 2231-5381
Fig.14.Load-deflection graph (IS 456:2000 (with and without GFRP))
Figure 14 shows the difference of load versus displacement
curves between designs of beam column joint as per
IS456:2000 without and with GFRP modelling. The model
(designed as per IS456:2000 without GFRP) yields
displacement of 2.48 mm for a load of 20kN, corresponding
for with GFRP is 1.5623 mm. By comparing specimen for
20kN load 37% deflection higher in IS456:2000 without
GFRP than as compared with specimen with GFRP
C. Comparing the deflection values of beam column joint
designed as per is 13920:1993 without GFRP and with
GFRP
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International Journal of Engineering Trends and Technology (IJETT) – Volume 28 Number 8 - October 2015
Fig.15.Load-deflection graph (IS 13920:1993 (with and without GFRP))
Figure 15 shows the difference of load versus displacement
curves between designs of beam column joint as per IS 13920:
1993 without and with GFRP modelling. The model (designed
as per IS13920: 1993 without GFRP) yields displacement of
1.739 mm for a load of 20kN, corresponding for with GFRP is
1.3935 mm. By comparing specimen for 20kN load 20%
deflection higher in IS13920: 1993 without GFRP than as
compared with specimen with GFRP.
D. Efficiency comparison of beam column joint designed as
per is 456 and is 13920: 1993 (with and without GFRP)
following conclusions were arrived based on the finite
element analysis of beam column joint.
The deflection of the exterior beam column joint
specimen(without GFRP) detailed as per code IS139201993 was found to be 30% lower than that of the
specimen detailed per code IS 456-2000.
The deflection of the exterior beam column joint
specimen wrapped with GFRP sheet reduced the
deflection about 37 %.when compared with the deflection
of specimen detailed as per code IS 4562000.
The deflection of the exterior beam column joint
specimen wrapped with GFRP sheet reduced the
deflection about 20 %.when compared with the deflection
of specimen detailed as per code IS13920-1993
The deflection of the exterior beam column joint
specimen(with GFRP) detailed as per code IS139201993 was found to be 11 % lower than that of the
specimen detailed per code IS 456-2000.
ACKNOWLEDGMENT
The authors sincerely thank the management authorities of
Ilahia College of engineering and technology, mulavoor, for
their consistent support and facilities provided.
REFERENCES
[1]
Fig.16.Load verses% of efficiency graph (IS 456:2000 and IS 13920: 1993)
The beam column joint wrapped with GFRP, then its
efficiency increases. By comparing the efficiency of GFRP up
to 10kN linearly varying in both cases, after 10kN beam
column joint designed as per IS13920: 1993 more efficient
than IS456. For a load of 20 kN, 37% efficient IS456 with
GFRP than without GFRP and 20% efficient IS13920: 1993
with GFRP than without GFRP
VII. CONCLUSIONS
The structural modelling of an office building was done using
ETABS. Reinforcement detailing of beam column joint on the
basis of IS456-2000 and IS13920-1993 found out manually.
The use of the finite element method to analyse wrapped and
unwrapped beam column joint designed as per IS 456-2000
and IS13920- 1993 was evaluated. Load deflection curve
plotted up to a controlled load of 20kN. Efficiency of beam
column joint evaluated on the basis of deflection. The
ISSN: 2231-5381
N. Ganesan., P.V. Indira., and Ruby Abraham., Steel fibre
reinforced high performance concrete Beam-column joints
subjected to cyclic loading. ISET Journal of Earthquake
Technology., Vol. 44, No. 3-4, Sept.-Dec. 2007, pp. 445–456.
[2] Mrs. S. M. Kulkarni, Dr. Y.D. Patil A State-of-art Review On
Reinforced Concrete Beam-column Joints. Journal Of Information,
Knowledge And Research In, ISSN: 0975 – 6744., Vol.2, Nov11oct12, pp.94-98
[3] A.G. Kay Dora., and N.H. Abdul Hamid., (2012), Seismic
Performance of SFRC Beam-Column Joint with Corbel under
Reversible Lateral Cyclic Loading. IACSIT journal , Vol. 4, No.
1,76-80.
[4] S. S. Patil., S. S. Manekari., A study of R.C.C. Beam-column
connection subjected to monotonic loading IJEIT journal, April
2013,Vol.2, 49-58
[5] T. Subramani et al., Finite Element Modelling On Behaviour Of
Reinforced Concrete Beam Column Joints Retrofitted With CFRP
Sheets Using ANSYS . Int. Journal of Engineering Research and
Applications ISSN : 2248-9622, Vol. 4, Issue 12( Part 5),
December 2014, pp.69-76
[6] B.C Punmia, ―Advanced Reinforced Concrete Design‖, CBS
Publishers and Distributors, New Delhi.
[7] N Krishna Raju, “Advanced Reinforced Concrete Design‖, C.B.S
Publishers and Distributers, New Delhi, First Edition.
[8] IS 456-2000,‖ Indian Standard Plain and Reinforced ConcreteCode of Practise‖, Bureau of Indian Standards ,New Delhi.
[9] IS 875(Part-1)-1987 ―Indian Standard Code of Practice for the
Design of dead loads‖, Bureau of Indian Standards ,New Delhi.
[10] IS 875(Part-2)-1987 ―Indian Standard Code of Practice for the
Design of live loads‖ , Bureau of Indian Standards ,New Delhi.
[11] IS 13920-2002 ―ductile detailing of reinforced Concrete structures
subjected to Seismic forces”, Bureau of Indian Standards ,New
Delhi.
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