Experimental study on bending behaviour of triangular

IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
__________________________________________________________________________________________
Volume: 02 Issue: 10 | Oct-2013, Available @ http://www.ijret.org 384
EXPERIMENTAL STUDY ON BENDING BEHAVIOUR OF TRIANGULAR
WEB PROFILE STEEL BEAM SECTION
Fatimah De’nan1
, Nor Salwani Hashim2
1
Senior Lecturer, 2
Phd Student, School of Civil Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang,
Malaysia, fatimahdenan@yahoo.com, wani_a02@yahoo.com
Abstract
A triangular web profile (TRIWP) steel section is a section made of two flanges connected to a slender web. The web and the flanges
can be produced from different steel grades depending on design requirements. The flanges width and thickness is determined based
on the depth of the section. The web is corrugated at regular interval into triangular shape along the length of the beam. This paper
describes an experimental study on the bending behavior in major (Ix) and minor (Iy) axes of Triangular Web Profile (TRIWP)
compared to flat web (FW) steel sections. Two types of sizing involved which is 200×100×6×3mm and 180×75×5×2mm section.
Each of beam section was modeled using several spans such as 3m, 4m and 4.8m. It was observed that the TRIWP section had a higher
stiffness about minor axis compared to that of FW steel section but has lower stiffness about major axis. The analyses results show
that the flexural stiffness for TRIWP1 is 0.794 times the Ix of the flat web steel section (FW1). Meanwhile, the flexural stiffness for
TRIWP1 is 1.429 times the Iy of the flat web steel section (FW1). The findings for section TRIWP2 found to be similar to that of TRIWP1.
For the section TRIWP2, it was observed that the value of Ix of TRIWP is 0.780 times the Ix of FW steel section which is less than that of
FW. The Iy of TRIWP is 1.393 times the Iy of FW steel section which is more than that of FW steel section.
Keywords: Flexural stiffness, Bending, Triangular web profile.
---------------------------------------------------------------------***------------------------------------------------------------------------
1. INTRODUCTION
This paper discusses the determination of the second moment
of area on minor (Iy) and major (Ix) axes of a triangular web
profile (TRIWP) steel section (see Figure 1). The second
moment of area values in major and minor axes can be easily
calculated for a normal flat web (FW) plate girder. This is
because the web is flat and uniform in profile throughout the
length. For a TRIWP steel section, the calculation of the second
moment of area is difficult due to the corrugated shape of the
web. The early studies have been done by Elgaaly which is
concentrated on the vertically trapezoidal corrugation. He
investigated the failure mechanisms of these beams under
different loading modes such as bending mode, shear mode
and compressive patch loads. It was found that the failure of
beams under shear loading is due to local buckling on the web
for coarse corrugation and global buckling on the web for
dense corrugation (Elgaaly et al., 1996). They also found that
the contribution of the web profile could be neglected in the
calculation of the second moment of area of the TWP section,
due to its insignificant contribution towards the beam load-
carrying capability (Elgaaly et al., 1997). However, it was
found that the web might have a contribution towards
increasing the second moment of area.
Nevertheless, under compressive patch loads, two distinct
modes of failure observed. These involve the formation of
collapse mechanism on flange followed by the web crippling
or yielded web cripples followed by vertical bending of the
flange into the crippled web. The failure of these beams is
found to be dependent on the loading position and corrugation
parameters where it can be a combination of the
aforementioned modes (Elgaaly et al., 1997). Thus, further
studies should be conducted to obtain a clearer understanding
about this issue.
Besides that, the two distinct modes of failure under the effect
of patch loading were dependent on the loading position and
the corrugation parameters was investigated by Johnson and
Cafolla (1997) and were further discussed in their writings.
While, Luo and Edlund (1996) addressed the differences in
results between an experimental and analytical analysis, was
due to a consideration adopted in modeling. They found that
the ultimate strength of a Ramberg–Osgood strain hardening
model is 8–12% higher than an elastic–plastic model. About
7% reduction of ultimate load was contributed by the presence
of local imperfection and global imperfection does not have
much effect. While the corner effects due to cold forming has
an insignificant effect on the ultimate strength. The ultimate
strength is found to be 20% and 40% lower when a knife load
was applied in comparison to uniform distributed patch load
with patch length of 50 and 115.2 mm, respectively. The
highest value of strength obtained when the girder is loaded at
the centre of the oblique part of corrugation and the lowest
value was obtained at the centre of the flat part. Besides that,
girders with larger corrugation angle and thicker web and

__________________________________________________________________________________________
flange have higher ultimate strength or ultimate shear
capacity. In addition, the experimental tests conducted by
Zhang et al. (2000) and Li et al. (2000) was found that the
corrugated web beam has 1.5–2 times higher buckling
resistance than the plane web beam.
Fig -1: Shape and dimensions of a typical TRIWP section (all units are in mm)
In order to use corrugated plates in the webs of the I-girder, it
is important to understand the flexural and torsional behaviors
of the I-girder with corrugated webs. However, studies on
such behaviors are scarce. In particular, despite the importance
of lateral–torsional buckling, it has been addressed by Sayed-
Ahmad (2005) and Moon (2009) in their papers.
Abbas et al. (2006) developed a theoretical formulation of the
linear elastic in-plane and torsional behavior of corrugated
web I-girders under in-plane loads and further theoretical,
experimental, and finite element analysis results for the linear
elastic behavior of corrugated web I-girders under primary
bending moment and shear, focusing primarily on the
phenomenon of transverse flange bending Abbas et al. (2007).
However, steel beam with corrugated web such as trapezoidal
web have been widely used in recent years. Therefore, a new
type of steel section namely triangular web profile (TRIWP)
will be studied in this paper to know the significant effect to
bending behaviour as the transverse stiffeners will be
eliminate and slanting stiffeners will be introduce in TRIWP
steel section.
2. THEORY
When a point load, P, is applied at the mid span of a simply
supported beam, the maximum deflection, δmax for elastic
condition, of the span can be calculated as:

48
1
Where,
I = second moment of area
P = applied point load
L = span of beam
E = elastic modulus of steel
δ = vertical deflection at mid span
A linear relationship between the load (P) versus deflection
(δ) graph will represent the value of constant containing I.
Since the length (L) and Young Modulus (E) for all models are
known, the I value for the TRIWP steel section can be obtained
from the slope of P−δ plot obtained from experimental study.
If two beams with the same material and length, the ratio of
their moments of inertia, I1 and I2, will lead to (rearranging the
Equation 1):

IJRET: International Journal of Research in Engineering and Technology
__________________________________________________________________________________________
Volume: 02 Issue: 10 | Oct-2013, Available @

Thus, if finite element analysis for the TRIWP and FW steel
sections are performed, the second moment of area,
TRIWP section about any axis can be determined provided the
second moment of area, I, of FW section of that axis is known,
using Equation 3.

The values of the flexural stiffness (P/δ) for the corrugated
steel section such as trapezoidal web profile, T
sections can be obtained from the P−δ graphs plotted from
appropriate bending analysis.
3. EXPERIMENTAL STUDY
3.1 Introduction
The detail dimensions of the test specimens are given in Table
1. The load deflections results were then used to obtain the
and Iy value of the TRIWP steel sections.
Table -1:
200×100×6×3mm
200×100×6×3mm
180×75×5×2mm
180×75×5×2mm
IJRET: International Journal of Research in Engineering and Technology eISSN: 2319
__________________________________________________________________________________________
2013, Available @ http://www.ijret.org
2
WP and FW steel
sections are performed, the second moment of area, I, for a
WP section about any axis can be determined provided the
W section of that axis is known,
3
) for the corrugated
steel section such as trapezoidal web profile, TRIWP and FW
graphs plotted from
The detail dimensions of the test specimens are given in Table
1. The load deflections results were then used to obtain the Ix
3.2 Bending Test Equipment and Set
The specimen was laid down about major axis with the web
facing up for the Ix bending (see Figure 2). All type of
specimens was simply supported at both ends. The beam is
restrained from moving sideways to make sure that the beam
undergoes a vertical bending. This is to make sure that the test
was carried out in bending only without any lateral torsional
buckling effects. Five vertical displacement transducers
labelled as LVDT1, LVDT
respectively were located under the bottom flange. LVDT3
was placed at the centre of the specimen, which is below the
loading point. As a guide to make sure the loading applied at
centre position, LVDT2 and LVDT4 were located 300
from LVDT2, and LVDT1 and LVDT5 was placed 180 mm
from each end. Figure 3 and Figure 4 show the actual
conditions of the test for FW2 and T
minor and major axis, respectively. The loading process was
monitored using a load cell pla
and all data were collected and recorded by data logger.
1: Dimensions of TRIWP and FW steel section specimens
Case Type of
section
FW1
L=3m, 4m, 4.8 m
200×100×6×3mm
TRIWP1
L=3m, 4m, 4.8 m
200×100×6×3mm
FW2
L=3m, 4m, 4.8 m
180×75×5×2mm
TRIWP2
L=3m, 4m, 4.8 m
180×75×5×2mm
eISSN: 2319-1163 | pISSN: 2321-7308
__________________________________________________________________________________________
386
3.2 Bending Test Equipment and Set-Up
The specimen was laid down about major axis with the web
bending (see Figure 2). All type of
specimens was simply supported at both ends. The beam is
from moving sideways to make sure that the beam
undergoes a vertical bending. This is to make sure that the test
was carried out in bending only without any lateral torsional
buckling effects. Five vertical displacement transducers
labelled as LVDT1, LVDT2, LVDT3, LVDT4 and LVDT5
respectively were located under the bottom flange. LVDT3
was placed at the centre of the specimen, which is below the
loading point. As a guide to make sure the loading applied at
centre position, LVDT2 and LVDT4 were located 300 mm
from LVDT2, and LVDT1 and LVDT5 was placed 180 mm
from each end. Figure 3 and Figure 4 show the actual
conditions of the test for FW2 and TRIWP2 steel section in
minor and major axis, respectively. The loading process was
monitored using a load cell placed under the hydraulic jack
and all data were collected and recorded by data logger.
WP and FW steel section specimens

__________________________________________________________________________________________
Fig -2: The test instrument arrangement
(a) Specimen under bending about major axis
(b) Specimen under bending about minor axis
Fig -3: The actual test set up (FW1-Section 200×100×6×3
mm)
(a) Specimen under bending about major axis
(b) Specimen under bending about minor axis
Fig -4: The actual test set up (TRIWP1-Section 200×100×6×3 mm)

__________________________________________________________________________________________
3.3 Test Procedures
Bending tests were performed in different ranges of span such
as 3000 mm, 4000 mm and 4800 mm. The initial span of the
beam was 3000 mm. As the load P was increased, the
corresponding deflections at LVDT3 were recorded. The
readings of vertical deflection at LVDT2 and LVDT4 were
taken to act as a control, to ensure that the position of the point
load, P, was at mid span. Meanwhile, LVDT 1 and LVDT 5
are to ensure that no deflection occurs near the end of the
span. After the deflection data was recorded, the supports were
adjusted to 4000 mm span respectively, and the same
procedure was carried out for 4800 mm span as shown in
Figure 5. By using the data logger, the reading of vertical
deflection was first set to zero. At every load level, the reading
of vertical deflection was recorded. The test was stopped at
1/3 of design moment capacity before the elastic capacity of
the specimen was exceeded. The load applied was at the centre
of the beam (concentrated load), and the vertical deflection of
beam specimens were measured at mid span (LVDT3). The
deflection of LVDT2 and LVDT4, and LVDT1 and LVDT5
are found to be almost the same.
Fig -5: The position of LVDTs for the bending test (all units in mm)
4. RESULTS AND DISCUSSION
The maximum deflection results of experimental study for FW
and TRIWP steel section are summarized in Table 2 and Table
3. In this study, the deflections about major axis for TRIWP
steel section is more than that of FW steel section (Table 2(a)
and Table 3(a)). However, deflection about minor axis for
TRIWP steel section is less than FW steel section as
summarized in Table 2(b) and Table 3(b). It means that the
TRIWP steel section is stiffer compared to FW steel section
about minor axis. In other word, TRIWP steel section has a
higher resistance to bending about minor axis than FW steel
section.
Table -2: Deflections for TRIWP1 and FW1 steel section
(Section 200×100×6×3)
(a) Point load 14 kN about major axis
Span
(mm) (mm) (mm)
!"
(mm)
Equation 1
3000 4.403 3.088 2.908
4000 8.806 6.924 6.894
4800 14.616 13.100 11.913
(b) Point load 3 kN about minor axis
Span
(mm) (mm) (mm)
!"
(mm)
Equation 1
3000 5.536 8.057 8.071
4000 12.789 17.283 19.130
4800 22.015 32.776 33.060
Table -3: Deflections for TRIWP2 and FW2
(Section180×75×5×2)
(a) Point load 8 kN about major axis
Span
(mm) (mm) (mm)
!"
(mm)
Equation 1
3000 4.951 3.636 3.281
4000 9.811 7.856 7.777
4800 16.754 13.502 13.440
(b) Point load 1 kN about minor axis
Span
(mm) (mm) (mm)
!"
(mm)
Equation 1
3000 5.280 7.710 7.654
4000 14.452 18.343 18.140
4800 21.230 30.858 31.346

__________________________________________________________________________________________
Table 4 and Table 5 show the flexural stiffness results about
major and minor axis respectively for TRIWP steel section
compared to FW steel section for both sizes. The analyses
result show that the flexural stiffness for TRIWP1 is 0.794
times the Ix of the flat web steel section (FW1) (see Table 4).
Meanwhile, the flexural stiffness for TRIWP1 is 1.429 times
the Iy of the flat web steel section (FW1) (see Table 4).
The findings for section TRIWP2 found to be similar to that of
TRIWP1. For the section TRIWP2, it was observed that the
value of Ix of TRIWP is 0.780 times the Ix of FW steel section
which is less than that of FW (see Table 5). The Iy of TRIWP is
1.393 times the Iy of FW steel section which is more than that
of FW steel section (see Table 5).
Table 4: Percentage differences of flexural stiffness for TRIWP1 and FW1 steel section (Section 200×100×6×3)
Position
Length
(mm)
Flexural stiffness (kN/mm)
1
1
FW
WPT
P
P
RI












δ
δ
( ) 1WPTRI
P
δ
( ) 1FW
P
δ
Major
axis
3000 3.180 4.534 0.701
4000 1.590 2.022 0.786
4800 0.958 1.069 0.896
Average 0.794
Minor
axis
3000 0.542 0.372 1.457
4000 0.235 0.174 1.351
4800 0.136 0.092 1.478
Average 1.429
Table 5: Percentage differences of flexural stiffness for TRIWP2 and FW2 steel section (Section180×75×5×2)
Position
Length
(mm)
Flexural stiffness (kN/mm)
2
2
FW
WPT
P
P
RI












δ
δ
( ) 1WPTRI
P
δ
( ) 1FW
P
δ
Major
axis
3000 1.616 2.200 0.735
4000 0.815 1.018 0.801
4800 0.477 0.593 0.804
Average 0.780
Minor
axis
3000 0.189 0.130 1.454
4000 0.069 0.055 1.255
4800 0.047 0.032 1.469
Average 1.393
In summary, the deflection about minor axis for TRIWP for
both sizes is less than FW steel section. It means that the
TRIWP steel section is stiffer compared to FW steel section
about minor axis. While the deflections about major axis for
TRIWP is more than that of FW steel section.
CONCLUSIONS
Therefore, this study is reliable for investigating the bending
behavior about minor and major axis. The laboratory testing
results indicated that the deflection about minor axis for
TRIWP steel section is less than FW. It means the TRIWP steel
section is stiffer compared to FW steel section about minor
axis. In this regard, TRIWP steel section has a higher resistance

__________________________________________________________________________________________
to bending about minor axis than FW steel section.
Meanwhile, the deflections about major axis for TRIWP steel
section is more than that of FW steel section. It means that the
FW is stiffer than TRIWP steel section about major axis. It can
be concluded that the introduction of slanting stiffeners shows
higher resistance in bending behavior compare to that of
corrugated section by using trapezoidal web.
ACKNOWLEDGEMENTS
The authors gratefully acknowledge the financial support of
Universiti Sains Malaysia (USM), and the technical assistance
support of Civil Engineering Lab Technician during the course
of the research. This research was also made possible by the
Short Term Grant (Account Number:
304/PAWAM/60312007) provided by the Universiti Sains
Malaysia.
REFERENCES
[1]. Elgaaly, M., Hamilton, R. W. & Seshadri, A. (1996).
Shear Strength of Beams with Corrugated Webs.
Journal of Structural Engineering, Vol. 122, pp.390-
398.
[2]. Elgaaly, M., Seshadri, A. & Hamilton, R. W. (1997).
Bending Strength of Steel Beams with Corrugated
Webs. Journal of Structural Engineering, Vol. 123,
pp.772-782.
[3]. Elgaaly, M. & Seshadri, A. (1997). Girders with
Corrugated Webs under Partial Compressive Edge
Loading. Journal of Structural Engineering, Vol. 123,
pp.783-791.
[4]. Elgaaly, M. & Seshadri, A. (1998). Depicting the
behavior of girders with corrugated webs up to failure
using non-linear finite element analysis. Advances in
Engineering Software, Vol. 29, pp.195-208.
[5]. Johnson, R. P. & Cafolla, J. (1997). Local flange
buckling in plate girders with corrugated webs.
Proceedings of the Institution of Civil Engineers:
Structures and Buildings, Vol. 122, pp.148-156.
[6]. Johnson, R. P. & Cafolla, J. (1997). Corrugated webs
in plate girders for bridges. Proceedings of the
Institution of Civil Engineers: Structures and
Buildings, Vol. 122, pp.157-164.
[7]. Luo, R. & Edlund, B. (1996). Ultimate strength of
girders with trapezoidally corrugated webs under patch
loading. Thin-Walled Structures, Vol. 24, pp.135-156.
[8]. Luo, R. & Edlund, B. (1996). Shear capacity of plate
girders with trapezoidally corrugated webs. Thin-
Walled Structures, Vol. 26, pp.19-44.
[9]. Li Y, Zhang W, Zhou Q, Qi X, Widera GEO. (2000)
Buckling strength analysis of the web of a WCW H-
beam: Part 2. Development and research on H-beams
with wholly corrugated webs (WCW). Journal of
Materials Processing Technology, Vol. 101(1), pp.
115–118.
[10]. Chan, C. L., Khalid, Y. A., Sahari, B. B. & Hamouda,
A. M. S. (2002). Finite element analysis of corrugated
web beams under bending. Journal of Constructional
Steel Research, Vol. 58, pp.1391-1406.
[11]. Khalid, Y. A., Chan, C. L., Sahari, B. B. & Hamouda,
A. M. S. (2004). Bending behaviour of corrugated web
beams. Journal of Materials Processing Technology,
Vol. 150, pp.242-254.
[12]. Sayed-Ahmed, E. Y. (2005). Lateral torsion-flexure
buckling of corrugated web steel girders. Proceedings
of the Institution of Civil Engineers: Structures and
Buildings, Vol. 158, pp.53-69.
[13]. Moon, J., Yi, J.-W., Choi, B. H. & Lee, H.-E. (2009).
Lateral-torsional buckling of I-girder with corrugated
webs under uniform bending. Thin-Walled Structures,
Vol. 47, pp.21-30.
[14]. Abbas, H. H., Sause, R., and Driver, R. G. (2006).
Behavior of corrugated web I-girders under in-plane
loads. Journal of Engineering Mechanics, Vol. 132(8),
pp.806–814.
[15]. Abbas, H. H., Sause, R., and Driver, R. G. (2007).
Analysis of Flange Tranverse Bending of Corrugated
Web I-Girders under In Plane Loads. Journal of
Structural Engineering, Vol. 132(8), pp. 806–814.
[16]. Zhang W, Zhou Q, Li Y, Cai Z, Widera GEO. (2000)
Hot rolling technique and profile design of tooth-shape
rolls. Part 1: Development and research on H-beams
with wholly corrugated webs. Journal of Materials
Processing Technology, Vol. 101(1), pp. 110–114.
[17]. Zhang W, Li Y, Zhou Q, Qi X, Widera GEO. (2000)
Optimization of the structure of an H-beam with either
a flat or a corrugated web. Part 3: Development and
research on H-beams with wholly corrugated webs.
Journal of Materials Processing Technology, Vol.
101(1), pp.119–23.
BIOGRAPHIES
Dr Fatimah De’nan, B.Tech & Ed. (Civil
Eng), MSc (Structural Eng.), PhD (Civil Eng-
Steel Structure) is a Senior Lecturer at the
School of Civil Engineering, Universiti Sains
Malaysia since 2008.
Nor Salwani Hashim, B. Eng. (Hon.) (Civil
Eng.), MSc (Civil Eng.) is a PhD student cum
Research Assistant at School of Civil
Engineering, Universiti Sains Malaysia.

Experimental study on bending behaviour of triangular

More Related Content

What's hot (20)

Viewers also liked (20)

Similar to Experimental study on bending behaviour of triangular (20)

More from eSAT Publishing House (20)

Recently uploaded (20)

Experimental study on bending behaviour of triangular