Experimental full-scale tests on steel portal frames for development of diaphragm action – Part II Effect of structural components on shear flexibility

Abstract

The Part II of this two-part paper evaluates the results of the experimental test series introduced in Part I. This research aimed to examine the major influencing parameters of stressed skin effect in industrially applied, nonstandard diaphragm configurations. As no international study was executed in state of art, in order to study the role of different variables to shear flexibility, a full-scale test series was executed at the Budapest University of Technology and Economics, Structural Engineering Department. In Part I the experimental test arrangement and shear flexibility results are introduced in comparison with the results derived from the ECCS formulae. This paper, denoted as Part II details the evaluation of full-scale test results by underlining conclusions regarding the effect of change in section size of structural components and the number of fixings, and the effect of variation in structural arrangements. The results of this investigation shows that in nonstandard cases the stiffening effect of diaphragms are comparable to the stiffening effect of bracing.

Full text

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EXPERIMENTAL FULL-SCALE TESTS ON STEEL PORTAL FRAMES FOR
DEVELOPMENT OF DIAPHRAGM ACTION – Part II
Effect of structural components on shear flexibility
Anita Lendvai, Attila László Joó
Department of Structural Engineering, Budapest University of Technology and Economics,
1112 Budapest, Műegyetem rkp. 3, Hungary
Email: lendvai.anita@epito.bme.hu
Abstract: The Part II of this two-part paper evaluates the results of the experimental test series
introduced in Part I. This research aimed to examine the major influencing parameters of
stressed skin effect in industrially applied, nonstandard diaphragm configurations. As no
international study was executed in state of art, in order to study the role of different variables
to shear flexibility, a full-scale test series was executed at the Budapest University of
Technology and Economics, Structural Engineering Department. In Part I the experimental test
arrangement and shear flexibility results are introduced in comparison with the results derived
from the ECCS formulae. This paper, denoted as Part II details the evaluation of full-scale test
results by underlining conclusions regarding the effect of change in section size of structural
components and the number of fixings, and the effect of variation in structural arrangements.
The results of this investigation shows that in nonstandard cases the stiffening effect of
diaphragms are comparable to the stiffening effect of bracing.
Keywords: full-scale tests, diaphragm action, trapezoidal sheet, profiled sheet, steel cladding,
stressed skin effect
1. Introduction
In Part I of this investigation a full-scale research program was introduced [1], which was
executed by the Budapest University of Technology and Economics in order to examine the
principal parameters influencing stressed skin effect in nonstandard diaphragm configurations

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[2-3], which are out of scope of current ECCS design methodology. The principal aim of the
research is to study the possible refinement of stressed skin design method and to adjust it to
the nonstandard cladding structural system applied in everyday construction all over Europe.
According to ECCS [4] method of stressed skin design may be used only if spacing of
seam fasteners between overlapping sheets should not exceed 500 mm, though in industrial
practice (especially in Hungary) installation of seam fasteners are often rejected. Fig. 1 shows
the difference between standard and nonstandard diaphragms.
Fig. 1. Standard (A) and nonstandard (B) diaphragms
As far as known, no international study was made in order to examine the stiffening effect
of these nonstandard diaphragm configurations. However international research regarding full-
scale tests of steel portal frames is overviewed in Part I of this two-part paper, in line with the
newest achievements [4] and trends for possible developments in stressed skin design of
standard diaphragms [5].
Several full-scale tests were conducted in Europe in order to examine the shear stiffness
of shear walls, where standard diaphragm configurations were examined. In 2004 a test series
was executed by Dubina et al [6], including 6 no. of full-scale wall tests with different claddings
(OSB and perforated sheeting). The aim of the research was to investigate the shear behaviour
of shear panels of most popular panel technologies. In these tests seam fasteners were
applied.

3
The stabilizing role of shear was underlined in a research project executed by Lange and
Naujoks [7] in timber framed constructions. Diaphragm action was examined in different
configurations (mostly with chipboards and gypsum fibreboard), but timber studs and framing
were used instead of cold-rolled sections.
The stiffness and strength characteristics for walls comprised of cold-formed steel studs
stabilised by OSB or gypsum board sheeting were studied by Schafer and Vieira [8].
Further studies were made in 2010 by Yu et al [9-10]. Monotonic and cyclic tests were
conducted in order to specify shear strength of specified shear walls. As the specimen size
was designed to fit one sheet width, so the seam fasteners are not relevant in these
experimental tests. Shear strength and peak load values were derived from the tests, each
configuration was designed according to AISI Lateral Design Standard.
An experimental study on the structural strength of cold-formed steel shear wall frames
with sheeting was conducted by Pan and Shan [11]. The sheeting type in these test series
were gypsum board, calcium silicate board and oriented strand board.
Five full-scale cantilever aluminium roof diaphragm tests were conducted by Avci et al [12]
in accordance with the AISI “Cantilever Test Method 1 for Cold-Formed Steel Diaphragms”.
The tests supporting the proposed use of panel edge term for aluminium diaphragms.
A series of shear wall tests were conducted in Canada to develop a design method for
steel sheathed cold-formed steel frame walls by Balh et al [13]. Similar configurations were
examined by Tian et al [14], where additional steel trusses were installed in diaphragms.
Though several full-scale tests were conducted in the subject, i.e. examining the shear
stiffness of shear walls, but all of the above included standard configurations with different type
of load bearing elements and sheetings. No international study was executed in order to
examine the stiffening effect of nonstandard diaphragms in cold-formed steel framed
structures, which is the novelty of our research program, and filling a gap in this research field.
Parallel with international research a preliminary research was executed at the Budapest
University of Technology and Economics, Structural Engineering Department [15]. The
conclusion of this preliminary numerical study shows that the stiffening effect of nonstandard

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diaphragms is non-negligable. The main finding of the study was that the eccentricity of the
diaphragm decreasing the shear stiffness of the diaphragms, which is not taken into account
in the current Eurocode formulae.
Fig 2. Test arrangement

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After the execution of the preliminary program a wide research program was executed at
the Department, including full-scale (see Fig. 2.) and panel tests, in order to capturing the
most important parameters of stressed skin effect, where the stiffening effect of diaphragms
used in everyday construction were examined [16].
Conclusions regarding the full-scale tests are included in this two-part paper: in Part I [1]
the test arrangement and the results of the full-scale experiments – shear flexibility values -
are detailed, while in this article conclusions are drawn in regards to the effect of the cladding
height and fixing number, and the effect of structural components to shear flexibility are
examined.
This two-part article focuses on the results of the full-scale experiment. After evaluation of
test results the effect of each influencing parameter is examined, and the principal influencing
parameters on shear flexibility are selected. This evaluation serves as a basis for future
purposes: for the execution of further experimental panel tests, the verification of the FE model
for panel test series, and the ultimate aim of the research is the extension of ECCS design
formulae to incorporate typical, nonstandard configurations, which will be the subject of a future
article.
2. Shear flexibility of structural components
2.1 ECCS method for calculation of stressed skin effect
The calculation of stressed skin effect according to ECCS is based on the component
method. The ECCS formulae incorporates the effect of 5 deformation components [2]:
 distortion of the profile (c1,1),
 shear strain in the faces of the profile (c1,2),
 deformation in the sheet to support member fasteners (c2,1).
 deformation in the seam fasteners (c2,2).
 deformation in the gable connections (c2,3).
 axial strain in the edge members, bending in the plane of the diaphragm (c3).
The shear flexibility can be calculated as the sum of the above components.

6
As the experimental tests were executed in elastic state, the flexibility of each structural
component can be calculated by using the same method as in ECCS: by adding or eliminating
flexibility results from the total value of shear flexibility.
This method gives the opportunity to make a comparison between each structural
component on the effect of shear flexibility.
In Sections 3-5 comparison between different test configurations was made in order to
examine the stiffening effect of each structural component. In Section 3 the effect of change in
section size of structural components in each configurations are detailed, while in Section 4
and 5 the role of the same structural components are examined in different configurations. The
range of examination can be seen on Fig. 3, where all the examined cases in Section 4 and 5
are shown in one figure.
Fig. 3. Examined cases – effect of structural elements

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3. Effect of section size and number of fixings on shear flexibility
3.1 Effect of the size of purlin section on shear flexibility
Next tables indicating the effect of increasing purlin section size to building flexibility. In the
last row of tables the change in flexibility is represented, which is the deviation of experimental
values from the configurations of Z200-Z150 purlin section sizes (the reference configurations
are those tests, where Z200 purlins in roof, and Z150 purlins in wall were applied).
In general it can be determined that the increase of section size increases the flexibility,
which means that eccentricity has principal effect on flexibility. Exceptions are the roof
diaphragm configurations where no internal cladding was applied (WPE-R).
Table 1 indicates the results of that configuration, which includes every structural elements
(bracing, inner and outer cladding, purlins – in roof and wall). This case clearly shows the effect
of increased section height, which is increasing flexibility up to109%.
WPEI-RW (1)
Flexibility (mm/kN)
A
B
X
Y
LTP45
Z200-Z150
0.072
0.081
0.072
0.175
Z250-Z200
0.151
0.101
0.128
0.142
LTP20
Z200-Z150
0.032
0.055
0.145
0.120
Z250-Z200
0.058
0.062
0.154
0.185
Change in
flexibility
(%)
LTP45
110 %
25 %
78 %
-19 %
LTP20
81 %
13 %
6 %
54 %
Table 1. Purlin size effect on flexibility WPEI-RW (1)
The same tendency is reflected by Table 2 where bracing was eliminated, so the effect of
cladding can be seen clearly. Change in purlin section height is affecting in up to 55% increase
in flexibility.
PEI-RW (2)
Flexibility (mm/kN)
A
B
X
Y
LTP45
Z200-Z150
0.032
0.088
0.165
0.288
Z250-Z200
0.032
0.137
0.205
0.292
LTP20
Z200-Z150
0.027
0.084
0.139
0.188
Z250-Z200
0.030
0.097
0.155
0.201
Change in
flexibility
(%)
LTP45
0 %
56 %
24 %
1 %
LTP20
11 %
15 %
12 %
7 %
Table 2. Purlin size effect on flexibility PEI-RW (2)
A B X Y
Z200-Z150 0.072 0.081 0.072 0.175
Z250-Z200 0.151 0.101 0.128 0.142
Z200-Z150 0.032 0.055 0.145 0.120
Z250-Z200 0.058 0.062 0.154 0.185
LTP45 109.722% 24.691% 77.778% -18.857%
LTP20 81.250% 12.727% 6.207% 54.167%
LTP45
LTP20
WPEI-RW (1)
Flexibility (mm/kN)
Change in
flexi bili ty (%)
A B X Y
Z200-Z150 0.032 0.088 0.165 0.288
Z250-Z200 0.032 0.137 0.205 0.292
Z200-Z150 0.027 0.084 0.139 0.188
Z250-Z200 0.030 0.097 0.155 0.201
LTP45 0.000% 55.682% 24.242% 1.389%
LTP20 11.111% 15.476% 11.511% 6.915%
PEI-RW (2)
Flexibility (mm/kN)
LTP45
LTP20
Change in
flexi bili ty (%)

8
PE-RW (3)
Flexibility (mm/kN)
A
B
X
Y
LTP45
Z200-Z150
0.042
0.193
0.278
0.417
Z250-Z200
0.050
0.197
0.304
0.454
LTP20
Z200-Z150
0.051
0.147
0.243
0.293
Z250-Z200
0.119
0.162
0.254
0.313
Change in
flexibility
(%)
LTP45
19 %
2 %
9 %
9 %
LTP20
133 %
10 %
5 %
7 %
Table 3. Purlin size effect on flexibility PE-RW (3)
Similarly in Table 3, where only external cladding was applied, the increase in flexibility
caused by increased purlin section height is up to133%.
Application of bracing in those variations where no internal cladding was installed is not
showing clear deviations, as shown in Table 4.
WPE-RW (4)
Flexibility (mm/kN)
A
B
X
Y
LTP45
Z200-Z150
0.055
0.066
0.125
0.140
Z250-Z200
0.061
0.035
0.174
0.150
LTP20
Z200-Z150
0.067
0.057
0.119
0.127
Z250-Z200
0.063
-
0.156
0.135
Change in
flexibility
(%)
LTP45
11 %
-47 %
39 %
7 %
LTP20
-6 %
-
31 %
6 %
Table 4. Purlin size effect on flexibility WPE-RW (4)
In Table 5-6 the influence of roof diaphragms to shear flexibility is recognized: increase in
purlin section height yields to decreased flexibility, in those cases where only external sheeting
was installed (configuration No. 5, see Table 6.). The decrease is significantly smaller in those
variations where LTP20 trapezoidal section was installed instead of LTP45, which is 4-20%
instead of 11-44%.
In those cases, where bracing is applied in roof diaphragm (configuration No. 8., see Table
5. ), the increasing section height in most cases increasing flexibility.
As bracing is installed in these configurations, we cannot draw clear conclusion regarding
th stiffening effect of diaphragms, because to total shear flexibility is influenced by the effect of
the pretension force of the wind bracing
A B X Y
Z200-Z150 0.042 0.193 0.278 0.417
Z250-Z200 0.050 0.197 0.304 0.454
Z200-Z150 0.051 0.147 0.243 0.293
Z250-Z200 0.119 0.162 0.254 0.313
LTP45 19.048% 2.073% 9.353% 8.873%
LTP20 133.333% 10.204% 4.527% 6.826%
PE-RW (3)
Flexibility (mm/kN)
LTP45
LTP20
Change in
flexi bi l ity (%)
A B X Y
Z200-Z150 0.055 0.066 0.125 0.140
Z250-Z200 0.061 0.035 0.174 0.150
Z200-Z150 0.067 0.057 0.119 0.127
Z250-Z200 0.063 0.439 0.156 0.135
LTP45 10.909% -46.970% 39.200% 7.143%
LTP20 -5.970% 670.175% 31.092% 6.299%
WPE-RW (4)
Flexibility (mm/kN)
LTP45
LTP20
Change in
flexi bili ty (%)

9
WPEI-R (8)
Flexibility (mm/kN)
A
B
X
Y
LTP45
Z200-Z150
0.157
0.576
0.587
0.756
Z250-Z200
0.199
0.738
0.511
0.720
LTP20
Z200-Z150
0.191
0.720
0.496
0.636
Z250-Z200
0.271
0.771
0.570
0.742
Change in
flexibility
(%)
LTP45
27 %
28 %
-13 %
-5 %
LTP20
42 %
7 %
15 %
17 %
Table 5. Purlin size effect on flexibility WPEI-R (8)
WPE-R (5)
Flexibility (mm/kN)
A
B
X
Y
LTP45
Z200-Z150
0.183
0.623
0.572
0.709
Z250-Z200
0.102
0.529
0.454
0.625
LTP20
Z200-Z150
0.190
0.648
0.572
0.735
Z250-Z200
0.153
0.752
0.532
0.701
Change in
flexibility
(%)
LTP45
-44 %
-15 %
-21 %
-12 %
LTP20
-19 %
16 %
-7 %
-5 %
Table 6. Purlin size effect on flexibility WPE-R (5)
In roof diaphragms where bracing was eliminated the value of 2-72 % increase in flexibility
is recognized due to the increase in purlin section height, results are shown in Tables 7-8.
PE-R (6)
Flexibility (mm/kN)
A
B
X
Y
LTP45
Z200-Z150
0.199
0.590
0.585
0.765
Z250-Z200
0.300
0.653
0.621
0.768
LTP20
Z200-Z150
0.164
0.690
0.054
0.736
Z250-Z200
0.282
0.707
-
0.758
Change in
flexibility
(%)
LTP45
51 %
11 %
6 %
0.4 %
LTP20
72 %
2 %
-
3 %
Table 7. Purlin size effect on flexibility PE-R (6)
PEI-R (7)
Flexibility (mm/kN)
A
B
X
Y
LTP45
Z200-Z150
0.172
0.537
0.562
0.744
Z250-Z200
0.187
0.644
0.592
0.762
LTP20
Z200-Z150
0.137
0.661
0.520
0.724
Z250-Z200
0.188
0.751
0.557
0.754
Change in
flexibility
(%)
LTP45
9 %
20 %
5 %
2 %
LTP20
37 %
14 %
7 %
4 %
Table 8. Purlin size effect on flexibility PEI-R (7)
A B X Y
Z200-Z150 0.183 0.623 0.572 0.709
Z250-Z200 0.102 0.529 0.454 0.625
Z200-Z150 0.190 0.065 0.572 0.735
Z250-Z200 0.153 0.752 0.532 0.701
LTP45 -44.262% -15.088% -20.629% -11.848%
LTP20 -19.474% 1060.494% -6.993% -4.626%
WPE-R (5)
Flexibility (mm/kN)
LTP45
LTP20
Change in
flexi bili ty (%)
A B X Y
Z200-Z150 0.199 0.590 0.585 0.765
Z250-Z200 0.300 0.653 0.621 0.768
Z200-Z150 0.164 0.690 0.054 0.736
Z250-Z200 0.282 0.707 0.545 0.758
LTP45 50.754% 10.678% 6.154% 0.392%
LTP20 71.951% 2.464% 911.132% 2.989%
PE-R (6)
Flexibility (mm/kN)
LTP45
LTP20
Change in
flexi bili ty (%)
A B X Y
Z200-Z150 0.172 0.537 0.562 0.744
Z250-Z200 0.187 0.644 0.592 0.762
Z200-Z150 0.137 0.661 0.520 0.724
Z250-Z200 0.188 0.751 0.557 0.754
LTP45 8.721% 19.926% 5.338% 2.419%
LTP20 37.226% 13.616% 7.115% 4.144%
PEI-R (7)
Flexibility (mm/kN)
LTP45
LTP20
Change in
flexi bi l ity (%)
A B X Y
Z200-Z150 0.157 0.576 0.587 0.756
Z250-Z200 0.199 0.738 0.511 0.720
Z200-Z150 0.191 0.720 0.496 0.636
Z250-Z200 0.271 0.771 0.570 0.742
LTP45 26.752% 28.125% -12.947% -4.762%
LTP20 41.885% 7.083% 14.919% 16.667%
Flexibility (mm/kN)
WPEI-R (8)
LTP45
LTP20
Change in
flexi bili ty (%)

10
Elimination of cladding is not resulting significant change in frame flexibility in those cases,
where no bracing was applied, as shown in Table 9.
Application of bracing is not showing clear tendencies in regards to frame flexibility in the
function of purlin section height, as Table 10 indicates.
P-R (9)/ P-RW (10)
Flexibility (mm/kN)
A
B
X
Y
P-R
Z200-Z150
0.796
1.055
1.046
1.303
Z250-Z200
0.779
1.068
1.025
1.290
P-RW
Z200-Z150
0.786
1.032
1.030
1.260
Z250-Z200
0.769
1.048
1.005
1.262
Change in
flexibility
(%)
LTP45
-2 %
1 %
-2 %
-1 %
LTP20
-2 %
2 %
-2 %
0.2 %
Table 9. Purlin size effect on flexibility P-R (9), P-RW (10)
WP-RW (11)/ WP-R (12)
Flexibility (mm/kN)
A
B
X
Y
WP-RW
Z200-Z150
0.094
0.113
0.158
0.243
Z250-Z200
0.112
0.178
0.226
0.208
WP-R
Z200-Z150
0.219
0.813
0.584
0.716
Z250-Z200
0.339
0.691
0.628
0.799
Change in
flexibility
(%)
LTP45
19 %
58 %
43 %
-14 %
LTP20
55 %
-15 %
8 %
12 %
Table 10. Purlin size effect on flexibility WP-RW (11), WP-R (12)
3.2 Effect of the size of trapezoidal sheeting section on shear flexibility
In this section the influence of trapezoidal sheeting section height is discussed in
comparison to the purlin section height. The values are referred to the configuration of Z200-
Z150-LTP20.
Similar main conclusion can be drawn as in previous section: the increase in sheeting size
is increasing flexibility in general.
A B X Y
Z200-Z150 0.796 1.055 1.046 1.303
Z250-Z200 0.779 1.068 1.025 1.290
Z200-Z150 0.786 1.032 1.030 1.260
Z250-Z200 0.769 1.048 1.005 1.262
LTP45 -2.136% 1.232% -2.008% -0.998%
LTP20 -2.163% 1.550% -2.427% 0.159%
P-RW
Change i n
flexi bili ty (%)
P-R (9)/ P-RW (10)
Flexibility (mm/kN)
P-R

11
Accordingly to Table 11 the increase in trapezoidal sheeting section height has influencing
effect on frame flexibility: it resulted in up to 53% increase in the flexibility in those
configurations, where no bracing was installed.
PEI-RW (2)
Flexibility (mm/kN)
A
B
X
Y
Z200-Z150
LTP20
0.027
0.084
0.139
0.188
LTP45
0.032
0.088
0.165
0.288
Z250-Z200
LTP20
0.030
0.097
0.155
0.201
LTP45
0.032
0.137
0.205
0.292
Change in
flexibility
(%)
Z200-Z150
19 %
5 %
19 %
53 %
Z250-Z200
7 %
41 %
32 %
45 %
Table 11. Trapezoidal sheeting size effect on flexibility PEI-RW (2)
In similar configurations where internal cladding was not applied, generally a value of 14-
45% increase in the flexibility was obtained (see Table 12).
PE-RW (3)
Flexibility (mm/kN)
A
B
X
Y
Z200-Z150
LTP20
0.051
0.147
0.243
0.293
LTP45
0.042
0.193
0.278
0.417
Z250-Z200
LTP20
0.119
0.162
0.254
0.313
LTP45
0.050
0.197
0.304
0.454
Change in
flexibility
(%)
Z200-Z150
-18 %
31 %
14 %
42 %
Z250-Z200
-58 %
22 %
20 %
45 %
Table 12. Trapezoidal sheeting size effect on flexibility PE-RW (3)
In roof diaphragms no clear tendency was observed. Similar values of flexibilities were
measured with the deviation of -7% to 25%, similarly in both cases: with or without the
installation of internal cladding, as indicated in Tables 13 - 14.
PE-R (6)
Flexibility (mm/kN)
A
B
X
Y
Z200-Z150
LTP20
0.164
0.690
0.054
0.736
LTP45
0.199
0.590
-
0.765
Z250-Z200
LTP20
0.282
0.707
0.545
0.758
LTP45
0.300
0.653
0.621
0.768
Change in
flexibility
(%)
Z200-Z150
21 %
-15 %
-
4 %
Z250-Z200
6 %
-8 %
14 %
1 %
Table 13. Trapezoidal sheeting size effect on flexibility PE-R (6)
A B X Y
LTP45 0.032 0.088 0.165 0.288
LTP20 0.027 0.084 0.139 0.188
LTP45 0.032 0.137 0.205 0.292
LTP20 0.030 0.097 0.155 0.201
Z200-Z150 18.519% 4.762% 18.705% 53.191%
Z250-Z200 6.667% 41.237% 32.258% 45.274%
PEI-RW (2)
Flexibility (mm/kN)
Z200-Z150
Z250-Z200
Change in
flexi bi l ity (%)
A B X Y
LTP45 0.042 0.193 0.278 0.417
LTP20 0.051 0.147 0.243 0.293
LTP45 0.050 0.197 0.304 0.454
LTP20 0.119 0.162 0.254 0.313
Z200-Z150 -17.647% 31.293% 14.403% 42.321%
Z250-Z200 -57.983% 21.605% 19.685% 45.048%
PE-RW (3)
Flexibility (mm/kN)
Z200-Z150
Z250-Z200
Change in
flexi bi l ity (%)
A B X Y
LTP45 0.199 0.590 0.585 0.765
LTP20 0.164 0.690 0.054 0.736
LTP45 0.300 0.653 0.621 0.768
LTP20 0.282 0.707 0.545 0.758
Z200-Z150 21.341% -14.493% 985.343% 3.940%
Z250-Z200 6.383% -7.638% 13.945% 1.319%
PE-R (6)
Flexibility (mm/kN)
Z200-Z150
Z250-Z200
Change in
flexi bi l ity (%)

12
PEI-R (7)
Flexibility (mm/kN)
A
B
X
Y
Z200-Z150
LTP20
0.137
0.661
0.520
0.724
LTP45
0.172
0.537
0.562
0.744
Z250-Z200
LTP20
0.188
0.751
0.557
0.754
LTP45
0.187
0.644
0.592
0.762
Change in
flexibility
(%)
Z200-Z150
25 %
-19 %
8 %
3 %
Z250-Z200
-0.5 %
-14 %
6 %
1 %
Table 14. Trapezoidal sheeting size effect on flexibility PEI-R (7)
3.3 Effect of number of fixings on shear flexibility
In configurations 6 and 7 two alternatives were designed in order to study the effect of
fixings. Variations ‘a’ are those specimens, where fixings were installed in every corrugations
instead of alternate corrugations. In the tables the deviation of experimental values are listed
from the results of those variations, where fixings are applied in alternate troughs (6 and 7).
In those specimens, where higher trapezoidal sheeting was installed (LTP45), a value of
17-40% decrease in flexibility are obtained, as indicated in Table 15.
PE-R (6-6a) / PEI-R (7-7a)
Flexibility (mm/kN)
A
B
X
Y
Z250-Z200-
LTP45
6
0.300
0.653
0.621
0.768
6a
0.178
0.513
0.461
0.635
7
0.187
0.644
0.592
0.762
7a
0.114
0.500
0.433
0.621
Change in
flexibility (%)
6
-41 %
-21 %
-26 %
-17 %
7
-39 %
-22 %
-27 %
-19 %
Table 15. Effect of application of number of fixings on flexibility
By applying smaller trapezoidal sheet sections (LTP20) the decrease in flexibility is smaller,
between 2-30%, as shown in Table 16.
PE-R (6-6a) / PEI-R (7-7a)
Flexibility
(mm/kN)
A
B
X
Y
Z250-Z200-
LTP20
6
0.282
0.707
0.545
0.758
6a
0.196
0.757
0.530
0.739
7
0.188
0.751
0.557
0.754
7a
0.137
0.728
0.524
0.725
Change in
flexibility
(%)
6
-30 %
7 %
-3 %
-3 %
7
-27 %
-3 %
-6 %
-4 %
Table 16. Effect of application of number of fixings on flexibility
A B X Y
LTP45 0.172 0.537 0.562 0.744
LTP20 0.137 0.661 0.520 0.724
LTP45 0.187 0.644 0.592 0.762
LTP20 0.188 0.751 0.557 0.754
Z200-Z150 25.547% -18.759% 8.077% 2.762%
Z250-Z200 -0.532% -14.248% 6.284% 1.061%
PEI-R (7)
Flexibility (mm/kN)
Z200-Z150
Z250-Z200
Change in
flexi bi l ity (%)
A B X Y
6 0.300 0.653 0.621 0.768
6a 0.178 0.513 0.461 0.635
7 0.187 0.644 0.592 0.762
7a 0.114 0.500 0.433 0.621
6 -40.667% -21.440% -25.765% -17.318%
7 -39.037% -22.360% -26.858% -18.504%
PE-R (6-6a) / PEI-R (7-7a)
Flexibility (mm/kN)
Change in
flexi bi l ity (%)
Z250-Z200-
LTP45
A B X Y
6 0.282 0.707 0.545 0.758
6a 0.196 0.757 0.530 0.739
7 0.188 0.751 0.557 0.754
7a 0.137 0.728 0.524 0.725
6 -30.496% 7.072% -2.752% -2.507%
7 -27.128% -3.063% -5.925% -3.846%
PE-R (6-6a) / PEI-R (7-7a)
Flexibility (mm/kN)
Z250-Z200-
LTP20
Change in
flexi bi l ity (%)

13
It can be stated that number of fixings has primary influencing effect in regards to the shear
flexibility of the building.
4. Shear flexibility of structural components
4.1 Effect of purlins on frame’s shear flexibility
To investigate the stiffening effect of purlins a comparison was made between the shear
flexibility of configurations No. 10 (frame with purlins in roof and wall) and 15 (frame).
The results in Table 17 showing that the presence of purlins is decreasing shear flexibility
by 0.117-0.023 mm/kN, which is about 3-8 % decrease in shear flexibility compared to the
configuration, where only the frame was examined.
A
B
X
Y
F-RW (15)
0.809
1.079
1.074
1.377
P-RW (10)
Z200-Z150
0.786
1.032
1.030
1.260
P-RW (10)
Z250-Z200
0.769
1.048
1.005
1.262
Decrease in flexibility (mm/kN)
-0.023
-0.047
-0.044
-0.117
-0.040
-0.031
-0.069
-0.115
Table 17. The effect of purlins in roof and wall on shear flexibility
A similar comparison was made between constructions No. 9 (frame with purlins in roof)
and 15 (frame), where the effect of roof purlins were studied.
The conclusion is that the roof purlins are decreasing shear flexibility by 0.011-0.087
mm/kN, which is 2-6% decrease in shear flexibility compared to the frame’s shear flexibility
value, see Table 18.

14
A
B
X
Y
F-RW (15)
0.809
1.079
1.074
1.377
P-R (9)
Z200-Z150
0.796
1.055
1.046
1.303
P-R (9)
Z250-Z200
0.779
1.068
1.025
1.290
Decrease in flexibility (mm/kN)
-0.013
-0.024
-0.028
-0.074
-0.030
-0.011
-0.049
-0.087
Table 18. The effect of purlins in roof on shear flexibility
Comparing the above 3 variations it can be stated that roof purlins has significant stiffening
effect in regards to the whole building, compared to wall purlins.
4.2 Effect of bracing on frame’s shear flexibility
In order to evaluate the effect of bracings to shear flexibility, configurations No. 14 and 15
were examined. The results underlining the primary role of bracing in decreasing the shear
flexibility of the structure, which is between 0.711-1.194 mm/kN, as indicated in Table 19.
The conclusion is that the usage of bracing is resulting in 8-10-times stiffer frame, than
without bracing.
A
B
X
Y
F-RW (15)
0.809
1.079
1.074
1.377
W-RW (14)
Z200-Z150
0.098
0.095
0.100
0.183
W-RW (14)
Z250-Z200
0.080
0.076
0.112
0.222
Decrease in flexibility (mm/kN)
-0.711
-0.984
-0.974
-1.194
-0.729
-1.003
-0.962
-1.155
Table 19. The effect of bracings in roof and wall on shear flexibility

15
Similar comparison was made between variations No. 13 (frame with bracing in roof) and
15 (frame). The results in Table 20. indicating, that the roof bracing is decreasing by 0.219-
0.646 mm/kN the shear flexibility of the structure. This is 20-47 % decrease in shear flexibility
compared to the experimental results of the hall shear flexibility.
A
B
X
Y
F-RW (15)
0.809
1.079
1.074
1.377
W-R (13)
Z200-Z150
0.270
0.860
0.546
0.731
W-R (13)
Z250-Z200
0.210
0.630
0.624
0.797
Decrease in flexibility (mm/kN)
-0.539
-0.219
-0.528
-0.646
-0.599
-0.449
-0.450
-0.580
Table 20. The effect of bracings in roof on shear flexibility
Summarizing the evaluation of the application of bracing it can be concluded, that bracing,
especially wall bracing main influence on shear flexibility. While roof bracing is increasing hall
stiffness 2-3 times, the application of roof and wall bracing is resulting in 8-10-times stiffer
frame.
4.3 Effect of trapezoidal sheeting on frame’s shear flexibility
The stiffening effect of trapezoidal sheeting was examined in various sheeting
configurations: variation No. 2 (external and internal cladding on roof and wall), No. 3 (external
cladding on roof and wall) and No. 10 (no cladding), see Table 21.
The below conclusion can be drawn from experimental test results:
 Application of external cladding is decreasing shear flexibility by 67-95 %.
 Application of internal cladding has a small influence on shear flexibility, which varies
between 1-11 % decrease.

16
 The application of internal and external cladding is resulting in 77-96 % decrease in
regards to the flexibility of the whole building. It can be stated that the application of
sheeting has a primary role in decreasing shear flexibility.
 The effect of change in purlin section size has a negligible small effect to change in
shear flexibility in these cases.
A
B
X
Y
Z200-Z150
P-RW (10)
0.786
1.032
1.03
1.26
PE-RW (3)
0.042
0.193
0.278
0.417
PEI-RW (2)
0.032
0.088
0.165
0.288
Flexibility of ext. cladding
-0.744
-0.839
-0.752
-0.843
Flexibility of int. cladding
-0.01
-0.105
-0.113
-0.129
Flexibility of cladding
-0.754
-0.944
-0.865
-0.972
Z250-Z200
P-RW (10)
0.769
1.048
1.005
1.262
PE-RW (3)
0.05
0.197
0.304
0.454
PEI-RW (2)
0.032
0.137
0.205
0.292
Flexibility of ext. cladding
-0.719
-0.851
-0.701
-0.808
Flexibility of int. cladding
-0.018
-0.06
-0.099
-0.162
Flexibility of cladding
-0.737
-0.911
-0.8
-0.97
Avarage
Flexibility of ext. cladding
-0.732
-0.845
-0.727
-0.826
Flexibility of int. cladding
-0.014
-0.083
-0.106
-0.146
Flexibility of cladding
-0.746
-0.928
-0.833
-0.971
Table 21. The effect of LTP45 trapezoidal sheeting in roof and wall on shear flexibility
Similar tendencies were observed by the application of LTP20 trapezoidal sheeting as
indicated in Table 22. The below tendencies were recognized:
 Application of external cladding is decreasing shear flexibility by 75-89 %.
 Application of internal cladding has a small influence on shear flexibility, which varies
between 3-10 % decrease.
 The application of internal and external cladding is resulting in 85-96 % decrease in
regards to the flexibility of the whole building, which underlines the primary role of
sheeting in decreasing shear flexibility.

17
 Similarly as in LTP45 cases the effect of change in purlin section size has a
negligible small effect to change in shear flexibility in these cases.
A
B
X
Y
Z200-Z150
P-RW (10)
0.786
1.032
1.03
1.26
PE-RW (3)
0.051
0.147
0.243
0.293
PEI-RW (2)
0.027
0.084
0.139
0.188
Flexibility of ext. cladding
-0.735
-0.885
-0.787
-0.967
Flexibility of int. cladding
-0.024
-0.063
-0.104
-0.105
Flexibility of cladding
-0.759
-0.948
-0.891
-1.072
Z250-Z200
P-RW (10)
0.769
1.048
1.005
1.262
PE-RW (3)
0.119
0.162
0.254
0.313
PEI-RW (2)
0.03
0.097
0.155
0.201
Flexibility of ext. cladding
-0.65
-0.886
-0.751
-0.949
Flexibility of int. cladding
-0.089
-0.065
-0.099
-0.112
Flexibility of cladding
-0.739
-0.951
-0.85
-1.061
Avarage
Flexibility of ext. cladding
-0.693
-0.886
-0.769
-0.958
Flexibility of int. cladding
-0.057
-0.064
-0.102
-0.109
Flexibility of cladding
-0.749
-0.950
-0.871
-1.067
Table 22. The effect of LTP20 trapezoidal sheeting in roof and wall on shear flexibility
In sheeting configurations the influence of roof sheeting to hall stiffness was examined by
comparing configurations No. 6 (external cladding in roof), 7 (external and internal cladding in
roof) and 9 (no cladding). Results are indicated in Table 23. with below conclusions:
 Application of external cladding is decreasing shear flexibility by 40-75 %.
 Application of internal cladding has a small influence on shear flexibility, which varies
between 1-5 % decrease at small purlin profiled cases, and 1-15 % at high profiled
ones.
 The application of internal and external cladding is resulting in 40-78 % decrease in
regards to the flexibility of the whole building, which underlines the primary role of
sheeting in decreasing shear flexibility.

18
 The effect of change in purlin section size has a negligible small effect to change in
shear flexibility in these cases.
A
B
X
Y
Z200-Z150
P-R (9)
0.796
1.055
1.046
1.303
PE-R (6)
0.199
0.59
0.585
0.765
PEI-R (7)
0.172
0.537
0.562
0.744
Flexibility of ext. cladding
-0.597
-0.465
-0.461
-0.538
Flexibility of int. cladding
-0.027
-0.053
-0.023
-0.021
Flexibility of cladding
-0.624
-0.518
-0.484
-0.559
Z250-Z200
P-R (9)
0.779
1.068
1.025
1.29
PE-R (6)
0.3
0.653
0.621
0.768
PEI-R (7)
0.187
0.644
0.592
0.762
Flexibility of ext. cladding
-0.479
-0.415
-0.404
-0.522
Flexibility of int. cladding
-0.113
-0.009
-0.029
-0.006
Flexibility of cladding
-0.592
-0.424
-0.433
-0.528
Avarage
Flexibility of ext. cladding
-0.538
-0.440
-0.433
-0.530
Flexibility of int. cladding
-0.070
-0.031
-0.026
-0.014
Flexibility of cladding
-0.608
-0.471
-0.459
-0.544
Table 23. The effect of LTP20 trapezoidal sheeting in roof on shear flexibility
In the above investigated configurations the below statements can be underlined in
regards to the effect of trapezoidal sheeting to the frame’s shear flexibility:
 Application of external cladding is decreasing shear flexibility by 67-95% on those
cases where cladding in wall and roof was installed, and a smaller decrease of 40-
75 % was experienced at roof diaphragms.
 Application of internal cladding has a small influence on shear flexibility, which varies
between 1-11% at those constructions, where roof and wall diaphragm was applied.
A smaller decrease of 1-5 % was investigated at roof diaphragms in small purlin
profiled cases, and 1-15 % at high profiled ones.

19
 The application of internal and external cladding is resulting in 77-96% decrease in
regards to the flexibility of the whole building, and a smaller change of 40-78 % was
introduced at roof diaphragms. This underlines the fundamental role of sheeting in
decreasing shear flexibility, especially roof diaphragms.
 The effect of change in purlin section size has a negligible small effect to change in
shear flexibility in these cases.
4.4 Effect of diaphragm on frame’s shear flexibility
The fundamental aim of the research program is to study the effect of built up systems from
cold rolled sections and trapezoidal sheeting to total frame flexibility, which was examined in
this subsection. To principal task is to underline the non-negligible stiffening effect of
diaphragms in nonstandard cases, so a comparison was made between frame flexibility (No.
15) and those variations where bracings were installed (No. 14 and No. 1), with those
configurations where only diaphragms were applied to stabilize the structure to in-plane shear
(No. 2).
The results are showing, that in each cases the application of bracing results in about 90 %
decrease in shear flexibility, compared to frame’s shear flexibility as indicated in Table 24-27.
A
B
X
Y
F-RW (15)
0.809
1.079
1.074
1.377
W-RW (14)
0.080
0.076
0.112
0.222
WPEI-RW (1)
0.151
0.101
0.128
0.142
PEI-RW (2)
0.032
0.137
0.205
0.292
Decrease in flexibility
(%)
W-RW (14)
90%
93%
90%
84%
WPEI-RW (1)
81%
91%
88%
90%
PEI-RW (2)
96%
87%
81%
79%
Table 24. The effect of diaphragms on shear flexibility, where Z250-Z200 purlin and LTP45 trapezoidal
sheeting is applied

20
A
B
X
Y
F-RW (15)
0.809
1.079
1.074
1.377
W-RW (14)
0.080
0.076
0.112
0.222
WPEI-RW (1)
0.058
0.062
0.154
0.185
PEI-RW (2)
0.030
0.097
0.155
0.201
Decrease in flexibility
(%)
W-RW (14)
90%
93%
90%
84%
WPEI-RW (1)
93%
94%
86%
87%
PEI-RW (2)
96%
91%
86%
85%
Table 25. The effect of diaphragms on shear flexibility, where Z250-Z200 purlin and LTP20 trapezoidal
sheeting is applied
A
B
X
Y
F-RW (15)
0.809
1.079
1.074
1.377
W-RW (14)
0.098
0.095
0.100
0.183
WPEI-RW (1)
0.072
0.081
0.072
0.175
PEI-RW (2)
0.032
0.088
0.165
0.288
Decrease in
flexibility (%)
W-RW (14)
88%
91%
91%
87%
WPEI-RW (1)
91%
92%
93%
87%
PEI-RW (2)
96%
92%
85%
79%
Table 26. The effect of diaphragms on shear flexibility, where Z200-Z150 purlin and LTP45 trapezoidal
sheeting is applied

21
A
B
X
Y
F-RW (15)
0.809
1.079
1.074
1.377
W-RW (14)
0.098
0.095
0.100
0.183
WPEI-RW (1)
0.032
0.055
0.145
0.120
PEI-RW (2)
0.027
0.084
0.139
0.188
Decrease in
flexibility (%)
W-RW (14)
88%
91%
91%
87%
WPEI-RW (1)
96%
95%
86%
91%
PEI-RW (2)
97%
92%
87%
86%
Table 27. The effect of diaphragms on shear flexibility, where Z200-Z150 purlin and LTP20 trapezoidal
sheeting is applied
The combined application of bracing and diaphragms (No. 1 configurations) is decreasing
shear flexibility by 81-91 % in high profiled cases (see Table 24.). A higher decrease in shear
flexibility of 86-96 % can be achieved if smaller profiles are installed, as the results underline
in Table 24-27.
The stiffening effect of diaphragms are examined in constructions No. 2. The decrease of
79-96 % is achieved by the application of diaphragms without bracings, regardless of the
section height of trapezoidal sheeting and the purlin section size.
In Table 28-29. the stiffening effect of sheeting is studied compared to bracing. The
measured flexibility values of the diaphragms (No. 2 and 3. configurations) are 45-87 % lower
close to the loading frame (at position ‘A’), than the configurations including wall bracing
without sheeting (configuration No. 11). In most cases the stiffening effect of smaller
trapezoidal sheeting section is higher by 5-16 %.

22
A
B
X
Y
WP-RW (11)
Z200-Z150
0.094
0.113
0.158
0.243
PEI-RW (2)
LTP20
0.027
0.084
0.139
0.188
PE-RW (3)
LTP20
0.051
0.147
0.243
0.293
PEI-RW (2)
LTP45
0.032
0.088
0.165
0.288
PE-RW (3)
LTP45
0.042
0.193
0.278
0.417
Decrease in flexibility (%)
71 %
26 %
12 %
23 %
45 %
-30 %
-54 %
-21 %
66 %
22 %
-4 %
-18 %
53 %
-70 %
-76 %
-72 %
Table 28. The effect of diaphragms on shear flexibility, where Z200-Z150 purlin is applied
A
B
X
Y
WP-RW (11)
0.112
0.178
0.226
0.208
PEI-RW (2)
LTP20
0.015
0.049
0.093
0.120
PE-RW (3)
LTP20
0.040
0.081
0.127
0.157
PEI-RW (2)
LTP45
0.032
0.137
0.205
0.292
PE-RW (3)
LTP45
0.050
0.197
0.304
0.454
Decrease in flexibility (%)
87 %
72 %
59 %
42 %
64 %
54 %
44 %
25 %
71 %
23 %
9 %
-40 %
55 %
-11 %
-35 %
-118 %
Table 29. The effect of diaphragms on shear flexibility, where Z250-Z200 purlin is applied
The overall conclusion is that the stiffening effect of diaphragm is comparable to bracing,
so the stiffening effect of diaphragms are non-negligible in nonstandard cases.

23
5. Effect of structural components in wall on shear flexibility
5.1 Effect of purlins in walls
In Table 30. the flexibility results of specimens No. 9 and 10 were compared in function of
increasing purlin section height. The tables well confirm that by applying purlins both in wall
and roof is decreasing frame flexibility by 17-40 %, compared to that investigated case, where
only roof purlins were installed.
Increasing section height of purlins does not have effect on shear flexibility in these cases.
Flexibility (mm/kN)
A
B
X
Y
Z200-Z150
P-R (9)
0.300
0.653
0.621
0.768
P-RW (10)
0.178
0.513
0.461
0.635
Z250-Z200
P-R (9)
0.187
0.644
0.592
0.762
P-RW (10)
0.114
0.500
0.433
0.621
Change in
flexibility
(%)
Z200-Z150
-40.667%
-21.440%
-25.765%
-17.318%
Z250-Z200
-39.037%
-22.360%
-26.858%
-18.504%
Table 30. Effect of application of purlins in wall on shear flexibility P-R (9), P-RW (10)
5.2 Effect of cladding in walls
In this section the effect of wall cladding is examined, thus the configurations 6 and 3 are
compared in Table 31., where the deviations of shear flexibility values from the configurations
including roof diaphragm only (PE-R (6)) are listed. The table well confirms that the effect of
cladding in walls is significant. The application of wall sheeting drastically decreases frame’s
shear flexibility, the amount of decrease varies within 40-83% in the investigated cases.

24
Flexibility (mm/kN)
A
B
X
Y
Z200-Z150-
LTP45
PE-R (6)
0.199
0.590
0.585
0.765
PE-RW (3)
0.042
0.193
0.278
0.417
Z250-Z200-
LTP45
PE-R (6)
0.300
0.653
0.621
0.768
PE-RW (3)
0.050
0.197
0.304
0.454
Change in
flexibility
(%)
Z200-Z150
-78.894%
-67.288%
-52.479%
-45.490%
Z250-Z200
-83.333%
-69.832%
-51.047%
-40.885%
Table 31. Effect of application of wall cladding on shear flexibility PE-R (6), PE-RW (3)
5.3 Effect of bracing and cladding in wall
Application of both cladding and bracing in walls is examined in next tables. The shear
flexibility results of configurations No. 8 and 1 are discussed, the change in flexibility is
indicated as the deviation from the results of configuration No. 8.
Installation of wall sheets yields to a decrease in total frame’s shear flexibility by 24-87 %.,
as shown in Table 32.
Flexibility (mm/kN)
A
B
X
Y
Z200-Z150-
LTP45
WPEI-R (8)
0.157
0.576
0.587
0.756
WPEI-RW (1)
0.072
0.081
0.072
0.175
Z250-Z200-
LTP45
WPEI-R (8)
0.199
0.738
0.511
0.720
WPEI-RW (1)
0.151
0.101
0.128
0.142
Change in
flexibility
(%)
Z200-Z150
-54.140%
-85.938%
-87.734%
-76.852%
Z250-Z200
-24.121%
-86.314%
-74.951%
-80.278%
Table 32. Effect of application of wall cladding and bracing on shear flexibility WPEI-R (8), WPEI-RW
(1) – LTP 45 sheeting

25
Similar tendency is recognized with higher deviations of 70-92 % at those configurations,
where smaller sheets are applied (see Table 33.).
Flexibility (mm/kN)
A
B
X
Y
Z200-Z150-
LTP20
WPEI-R (8)
0.191
0.720
0.496
0.636
WPEI-RW (1)
0.032
0.055
0.145
0.120
Z250-Z200-
LTP20
WPEI-R (8)
0.271
0.771
0.570
0.742
WPEI-RW (1)
0.058
0.062
0.154
0.185
Change in
flexibility
(%)
Z200-Z150
-83.246%
-92.361%
-70.766%
-81.132%
Z250-Z200
-78.598%
-91.958%
-72.982%
-75.067%
Table 33. Effect of application of wall cladding and bracing on shear flexibility WPEI-R (8), WPEI-RW
(1) – LTP20 sheeting
It can be stated that wall sheets has principal influence on shear flexibility, especially at
those configurations, where smaller trapezoidal section height is applied.
5.4 Effect of wind bracing in wall
The effect of wind bracing is examined by investigating constructions No. 12 and 11. The
change in flexibility is indicated as the deviation from the test results of configuration No. 12 .
Results in Table 34. underlining the significant impact of bracing in decreasing hall flexibility,
which value is within 57-86 % if these structural elements are applied both in wall and roof,
compared to those cases, where only roof bracings are applied. In these investigated cases
the change in purlin size is not influencing the shear flexibility.

26
Flexibility (mm/kN)
A
B
X
Y
Z200-Z150
WP-R (12)
0.219
0.813
0.584
0.716
WP-RW (11)
0.094
0.113
0.158
0.243
Z250-Z200
WP-R (12)
0.339
0.691
0.628
0.799
WP-RW (11)
0.112
0.178
0.226
0.208
Change in
flexibility
(%)
Z200-Z150
-57.078%
-86.101%
-72.945%
-66.061%
Z250-Z200
-66.962%
-74.240%
-64.013%
-73.967%
Table 34. Effect of application of bracing on shear flexibility WP-R (12), WP-RW (11)
Application of bracing in roof is decreasing flexibility by 21-86 % compared to unbraced
versions, as indicated in Table 35.
Flexibility (mm/kN)
A
B
X
Y
WP-
RW (11)
0.094
0.113
0.158
0.243
R (12)
0.219
0.813
0.584
0.716
P-
RW (10)
0.786
1.032
1.030
1.260
R (9)
0.796
1.055
1.046
1.303
Change in
flexibility (%)
P/WP-RW
-57.078%
-86.101%
-72.945%
-66.061%
P/WP-R
-72.137%
-21.221%
-43.301%
-43.175%
Table 35. Effect of application of bracing on shear flexibility
In Table 36. overall comparison was made regarding the effect of wind bracing. The
conclusion is, that bracing has principal influencing effect on frame flexibility in those cases,
where both the roof and wall are braced. The decrease in flexibility is measured to be the
maximum of 6 %.

27
In those variations, where bracing is applied in roof only, the stiffening effect of bracing is
negligible.
Flexibility (mm/kN)
A
B
X
Y
WPEI-
RW
0.072
0.081
0.072
0.175
PEI-
0.032
0.088
0.165
0.288
WPE-
RW
0.055
0.066
0.125
0.140
PE-
0.042
0.193
0.278
0.417
WPEI-
R
0.157
0.576
0.587
0.756
PEI-
0.172
0.537
0.562
0.744
WPE-
R
0.183
0.623
0.572
0.709
PE-
0.199
0.590
0.585
0.765
Change in
flexibility
(%)
PEI/WPEI-RW
125.000%
-7.955%
-56.364%
-39.236%
PE/WPE-RW
30.952%
-65.803%
-55.036%
-66.427%
PEI/WPEI-R
-8.721%
7.263%
4.448%
1.613%
PE/WPE-R
-8.040%
5.593%
-2.222%
-7.320%
Table 36. Effect of application of bracing on shear flexibility
5.5 Effect of inner cladding in wall
The examination of inner cladding to frame flexibility was evaluated by comparison of
construction No. 2-3 and 6-7. In general the conclusion can be drawn that inner cladding is
decreasing frame flexibility by 23-75 % (see Table 37. ). The inner cladding has major influence
on flexibility by roof diaphragms.

28
Flexibility (mm/kN)
A
B
X
Y
PEI-
RW
0.032
0.088
0.165
0.288
PE-
0.042
0.193
0.278
0.417
PEI-
R
0.172
0.537
0.562
0.744
PE-
0.199
0.590
0.585
0.765
Change in
flexibility (%)
PE/PEI-RW
-23.810%
-54.404%
-40.647%
-30.935%
PE/PEI-R
-75.581%
-64.060%
-50.534%
-43.952%
Table 37. Effect of application of inner cladding on shear flexibility
6. Conclusion
In this two-part paper the international research projects related to full-scale experiments in
regards to the examination of stressed skin effect are overviewed, however it was underlined
that no international study was made in order to examine the stiffening effect of nonstandard
diaphragms. Conclusion were drawn in order to further investigation and possible improvement
of current design procedure.
In accordance a full-scale experiment of a single bay steel cladded building was executed
by the Budapest University of Technology and Economics, Structural Laboratory in order to
capture the major influencing parameters of stressed skin effect in nonstandard configurations.
The test arrangement, the experimental test results and conclusions regarding the comparison
of the experimental results with the results derived from ECCS formulae are reviewed in Part
I this two-part article [1]. In this article the conclusions of the full-scale experimental test were
evaluated.
In Section 3 the effect of the section size and number of fixings on shear flexibility are
detailed; on these bases the following major conclusions can be drawn:
 Increasing section height of purlins result in increasing shear flexibility by 6-109% in
full cladded cases. Smaller increase, in the range of 1-55% was obtained in those cases
where no bracings were applied.

29
 In roof cladded and braced configurations a different tendency was observed:
increasing purlin height leads to increased flexibility by 11-44%. Elimination of bracing
leads to increasing flexibility in these cases.
 The increase in trapezoidal section height generally results in increasing flexibility, up
to 53%. This conclusion does not apply for diaphragms only in the roof.
 The number of fixings have principal influence on shear flexibility. By applying higher
sheets the decrease in flexibility is in the range of 17-40% of double amount of fixings
is applied. This range varies between 2-30% by the application of smaller height of
sheets.
In Section 4 the effect of the structural components applied in wall and roof on shear
flexibility were investigated and evaluated with the below conclusions:
 By examining the effect of purlin to the structure’s shear flexibility it can be stated, that
roof purlins has greater effect in stiffening the building (2-6%), than wall purlins.
 The application of roof bracing is increasing hall stiffness 2-3 times, while the
application of roof and wall bracing is resulting in 8-10-times stiffer frame. This
underlines that bracing has a primary influencing effect on the frame’s shear stiffness.
 Application of internal and external cladding is decreasing shear flexibility by 40-78 %,
which is underlining the non-negligible stiffening effect of steel cladding.
 Application of internal cladding has a small influence on shear flexibility compared to
external sheets. This value varies between 1-5 % decrease at small purlin profiled
cases, and 1-15 % at high profiled ones.
 By examining diaphragm effect the results underline that in nonstandard cases the
stiffening effect of diaphragms are comparable to the stiffening effect of bracing.
In Section 5 the below conclusions were drawn in regards to structural elements applied in
wall:
 The results well confirm that the presence of purlins in both wall and roof decreasing
shear flexibility by 17-40%.

30
 Installation of wall cladding drastically decreases flexibility by 24-87 %.
 Cladding and bracing of the structure is decreasing flexibility by 27-86 %, while
application only the bracing is causes a decrease of 57-86 % in uncladded frames.
 Inner cladding has a decreasing effect to flexibility by 23-75 %.
In this article the range of conclusions in Part I were expanded with the effect of structural
components to shear flexibility. Upon full-scale tests the influencing parameters are selected,
and are further examined in panel test series. Upon panel experiments a numerical model can
be validated and verified, so a wide range of tests can be observed by numerical simulations,
which will be the subject of a future article.
7. Acknowledgement
The results presented in this paper have been carried out within the research project “New
Széchenyi Plan, Operational Programmes of New Hungary Development Plan: GOP-1.1.1-11-
2012-0568”. The research has been developed by the help of the Structural Laboratory of BME
and industrial partner Rutin Ltd; the authors thankful for the support and valuable assistance.
References
[1] Lendvai A., Joó AL. Experimental full-scale tests for development of diaphragm action –
Part I. – Effect of cladding height to shear flexibility, 2017.
[2] European Recommendations for the application of metal sheeting acting as a diaphragm,
European Convention for Constructional Steelwork, No. 88, 1995.
[3] EN 1993-1-3: Eurocode 3: Design of steel structures: Part 1-3: General rules,
supplementary rules for cold-formed members and sheeting, 2005.
[4] Nagy Zs, Pop A, Mois I, Ballok R. Stressed skin effect on the elastic buckling of pitched
roof portal frames, Structures 2016, 8 (2): 227-244.
[5] Davies JM. Developments in stressed skin design. Thin-Walled Structures 2006; 44:
1250-1260.

31
[6] Fülöp LA., Dubina D. Performance of wall-stud cold-formed shear panels under
monotonic and cyclic loading, Part I: Experimental research. Thin-Walled Structures
2004; 42: 321-338.
[7] Lange J., Naujoks B. Behaviour of cold-formed steel shear walls under horizontal and
vertical loads. Thin-Walled Structures 2006; 44: 1214-1222.
[8] Schafer BW., Vieira LCM. Lateral stiffness and strength of sheathing braced cold-formed
steel stud walls. Engineering Structures 2012; 37: 205-213.
[9] Yu C. Shear resistance of cold-formed steel framed shear walls with 0.686 mm, 0.762
mm, and 0.838 mm steel sheat sheathing. Engineering Structures 2010; 32: 1522-1529.
[10] Yu C., Chen Y. Detailing recommendations for 1.83 m wide cold-formed steel shear walls
with steel sheathing. Journal of Constructional Steel Research 2011; 67: 93-101.
[11] Pan CL., Shan MY. Monotonic shear tests of cold-formed steel wall frames with
sheathing. Thin-walled Structures 2011; 49: 363-370.
[12] Avci O., Luttrell LD., Mattingly J., Samuel Easterling W. Diaphragm shear strength and
stiffness of aluminium roof panel assemblies. Thin-Walled Structures 2016; 106: 51-60.
[13] Balh N., DaBreo J., Ong-Tone C., El-Saloussy K., Yu C., Rogers CA. Design of steel
sheathed cold-formed steel framed shear walls. Thin-Walled Structures 2014; 75: 76-86.
[14] Tian H-W., Li Y-Q., Yu C. Testing of steel sheathed cold-formed steel trussed shear
walls. Thin-Walled Structures 2015; 94: 280-292.
[15] Schaul P. Stiffening effect of trapezoidal sheetings on the behaviour of steel halls, MSc
thesis, Department of Structural Engineering, Budapest University of Technology and
Economics, 2013 (in Hungarian).
[16] Joó AL., Dunai L. Full-scale experimental tests on steel frames with various claddings,
In: ICASS’15, Eight International Conference on Advances in Steel Structures, Lisbon,
Portugal, 22-24 July 2015., 1-16.