r - The Hong Kong Polytechnic University

where c = cope length,D = beam depth, d c
= cope depth, R cr
= critical reaction, τ cr
= critical shear stress, t w
=
web thickness, k s
= shear buckling coefficient, h 0
= height of web of T section.
The above equations are suitable for coped beams with relatively long coped length and coped depth since
elastic web buckling may occur. However, for coped beams with relatively short coped length and depth, local
web buckling may occur inelastically. Therefore, the above elastic web buckling equations might give
non-conservative prediction for coped beams with inelastic web buckling failure.
Figure 1 Top flange coped I beam
In 2004, ten full-scale coped beam tests were conducted by Zhong et al. to investigate the potential local failure
mode of coped steel I-beam with relatively short coped length and depth and it was shown that inelastic local
web buckling is one of the potential failure modes. In order to further study the local web buckling capacity of
coped steel I-beam with relatively short coped length and depth, finite element analysis was carried out to
analyze those test specimens with local web buckling failure. Subsequently, by using the validated finite element
model, parametric studies which included (1) web slenderness (d/t w ), (2) cope depth to beam depth ratio (d c /D), (3)
cope length to reduced web depth ratio (c/h o ) and (4) initial imperfection of web section, were conducted to obtain
the local web buckling capacity of coped steel I-beams.
FINITE ELEMENT MODEL FOR COPED BEAMS
General
Finite element method is employed to present the numerical analyses of local web buckling strength of coped
steel I-beams. All finite element (FE) models were modeled and analyzed using the finite element software
ABAQUS 6.7 (2007). The validity of the FE models were examined by comparing the numerical results of load
deflection curve of the models with those results obtained from the tests of Zhong et al. (2004). Detail test
procedures and results can be obtained from Zhong et al. (2004). In this paper, five finite element models were
established according to the dimension and materials details of the test specimens (A1, A2, B1, B2, and D1) of
Zhong et al. (2004). Detail dimensions of the specimens are shown in Table 1.
Table 1 The details of dimension of the test specimens of Zhong et al. (2004)
Test Web Flange Beam Flange Connected Connection Cope Cope Weld
No. Thickness Thickness Depth Width Length Position Length Depth Size
t w (mm) T (mm) D (mm) B (mm) a (mm) b (mm) p (mm) c (mm) d c (mm) s (mm)
A1 6.8 11.1 404.2 140.9 50 160 20 100 33 8.9
A2 6.8 11.1 404.2 140.9 70 140 20 120 31 9.4
B1 6.8 11.1 404.2 140.9 50 120 20 100 30 10
B2 6.8 11.1 404.2 140.9 90 110 20 130 30 9.9
D1 9.2 14.2 456.3 189.1 90 120 20 150 30 11.8
c
b'
p
b
dc
D
tw
s
s
a
B
T
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