on the design of perforated steel shear walls, an

17
On the design of perforated steel shear walls, an experimental and numerical study M MANSOURI 1 , M G VETR 2, * and M R JAVAHERI TAFTI 3 1 Department of Civil Engineering, Taft Branch, Islamic Azad University, Taft, Iran 2 Department of Civil Engineering, International Institute of Earthquake Engineering and Seismology, Tehran, Iran 3 Structural and Earthquake Research Center, Taft Branch, Islamic Azad University, Taft, Iran e-mail: [email protected] MS received 17 September 2020; revised 15 January 2021; accepted 18 February 2021 Abstract. Despite the considerable advantages of SPSW, there were some shortcomings concerning the system. Needing huge columns surrounding the infill plate has been the main dilemma of the SPSW system. This problem will be due to high imposed stresses to columns by the infill plate. Perforated SPSW has shown a capable method among the proposed methods to reduce applied forces to SPSW’s columns. In this paper, the optimum configuration of holes was investigated experimentally and numerically. Results indicated that the imposed forces to columns are reduced by increasing of hole area. The ultimate strength and energy absorption of perforated SPSW also are reduced by increasing of hole area. Therefore, the optimum configuration was proposed to achieve a minimum reduction in structural parameters and maximum reduction in column forces. Besides, new relations were proposed to calculate the structural parameters of the perforated SPSW. The proposed relations showed a good agreement with finite element results. Keywords. Perforated; SPSW; stiffness; drift; ultimate strength; ductility. 1. Introduction In addition to successful performance in experimental [15] and numerical studies [610] conducted by researchers, the steel shear wall (SPSW) has also performed well in past earthquakes. Past studies [11, 12] carried out on the system confirmed that they enjoy excellent energy absorption and ductility capacity, high initial stiffness, and ultimate strength. Excellence SPSW in comparison with other lateral bearing loads systems has persuaded designers to utilize the SPSW in their projects [13]. Therefore, the SPSW is an economical and applicable replacement for concrete walls and steel braces. The main dilemma concerning the system is needing the huge columns surrounding of infill plate. it is due to high stress by infill plate applied to columns. Although a thinner filler plate reduces stress in boundary columns, it does sig- nificantly reduce lateral stiffness and lateral strength. Also, even by using a thinner infill plate, the possibility of hinge formation is not reduced. Moreover, reducing of infill plate is made slenderness ratio limitation. Therefore, the reduction of infill plate thickness due to its limitation is not an applicable option for reducing imposed stress to boundary columns. To solve the problem, researchers proposed Low Yield Point (LYP) steel to reduce the imposed stress to columns without reduction of lateral strength, stiffness, and ductility [14, 15]. Although LYP steel improves the behavior of SPSW, it increases construction costs. Also, the LYP infill plate makes complicity during infill plate installing. In line with studies on LYP-SPSW, the researcher proposed semi-supported SPSW [16, 17] to reduce imposed stress in the main columns. Ghamari and co-worker [18] proposed an SPSW with sec- ondary oblique columns that improves the behavior of con- ventional semi-supported SPSW. In the semi-supported SPSW, two used secondary columns cause to reduce the imposed stress in columns. Although the semi-supported SPSW is reduced imposed stress considerably, lateral stiff- ness and strength are considerably reduced as well. Also, in the semi-supported SPSW concentrated stress is made in the beam. Among all methods proposed to overcome weakening the infill plate, the perforated SPSW (shown in figure 1) presented by Vian [19], showed a more successful behavior than other presented systems. It can be said that the first research on the perforated SPSW was done by Sabouri-Ghomi [20] which led to the proposition of Equation (1) based on the PFI method for estimating lateral strength of SPSW with the opening. V op ¼ 1 D d p :V p ð1Þ *For correspondence Sådhanå (2021)46:132 Ó Indian Academy of Sciences https://doi.org/10.1007/s12046-021-01587-3

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Page 1: On the design of perforated steel shear walls, an

On the design of perforated steel shear walls, an experimentaland numerical study

M MANSOURI1, M G VETR2,* and M R JAVAHERI TAFTI3

1Department of Civil Engineering, Taft Branch, Islamic Azad University, Taft, Iran2Department of Civil Engineering, International Institute of Earthquake Engineering and Seismology, Tehran,

Iran3Structural and Earthquake Research Center, Taft Branch, Islamic Azad University, Taft, Iran

e-mail: [email protected]

MS received 17 September 2020; revised 15 January 2021; accepted 18 February 2021

Abstract. Despite the considerable advantages of SPSW, there were some shortcomings concerning the

system. Needing huge columns surrounding the infill plate has been the main dilemma of the SPSW system. This

problem will be due to high imposed stresses to columns by the infill plate. Perforated SPSW has shown a

capable method among the proposed methods to reduce applied forces to SPSW’s columns. In this paper, the

optimum configuration of holes was investigated experimentally and numerically. Results indicated that the

imposed forces to columns are reduced by increasing of hole area. The ultimate strength and energy absorption

of perforated SPSW also are reduced by increasing of hole area. Therefore, the optimum configuration was

proposed to achieve a minimum reduction in structural parameters and maximum reduction in column forces.

Besides, new relations were proposed to calculate the structural parameters of the perforated SPSW. The

proposed relations showed a good agreement with finite element results.

Keywords. Perforated; SPSW; stiffness; drift; ultimate strength; ductility.

1. Introduction

In addition to successful performance in experimental [1–5]

and numerical studies [6–10] conducted by researchers, the

steel shear wall (SPSW) has also performed well in past

earthquakes. Past studies [11, 12] carried out on the system

confirmed that they enjoy excellent energy absorption and

ductility capacity, high initial stiffness, and ultimate strength.

Excellence SPSW in comparison with other lateral bearing

loads systems has persuaded designers to utilize the SPSW in

their projects [13]. Therefore, the SPSW is an economical

and applicable replacement for concrete walls and steel

braces. The main dilemma concerning the system is needing

the huge columns surrounding of infill plate. it is due to high

stress by infill plate applied to columns. Although a thinner

filler plate reduces stress in boundary columns, it does sig-

nificantly reduce lateral stiffness and lateral strength. Also,

even by using a thinner infill plate, the possibility of hinge

formation is not reduced. Moreover, reducing of infill plate is

made slenderness ratio limitation. Therefore, the reduction of

infill plate thickness due to its limitation is not an applicable

option for reducing imposed stress to boundary columns. To

solve the problem, researchers proposed Low Yield Point

(LYP) steel to reduce the imposed stress to columns without

reduction of lateral strength, stiffness, and ductility [14, 15].

Although LYP steel improves the behavior of SPSW, it

increases construction costs. Also, the LYP infill plate makes

complicity during infill plate installing. In line with studies

on LYP-SPSW, the researcher proposed semi-supported

SPSW [16, 17] to reduce imposed stress in themain columns.

Ghamari and co-worker [18] proposed an SPSW with sec-

ondary oblique columns that improves the behavior of con-

ventional semi-supported SPSW. In the semi-supported

SPSW, two used secondary columns cause to reduce the

imposed stress in columns. Although the semi-supported

SPSW is reduced imposed stress considerably, lateral stiff-

ness and strength are considerably reduced as well. Also, in

the semi-supported SPSW concentrated stress is made in the

beam. Among all methods proposed to overcome weakening

the infill plate, the perforated SPSW (shown in figure 1)

presented by Vian [19], showed a more successful behavior

than other presented systems.

It can be said that the first research on the perforated

SPSW was done by Sabouri-Ghomi [20] which led to the

proposition of Equation (1) based on the PFI method for

estimating lateral strength of SPSW with the opening.

Vop ¼ 1� D

dp

� �:Vp ð1Þ

*For correspondence

Sådhanå (2021) 46:132 � Indian Academy of Sciences

https://doi.org/10.1007/s12046-021-01587-3Sadhana(0123456789().,-volV)FT3](0123456789().,-volV)

Page 2: On the design of perforated steel shear walls, an

where Vop and Vp are the strength of a perforated and a

solid shear panel, respectively, D is the perforation diam-

eter, and dp is the panel height.

The equation was studied by Purba [21] for perorated

SPSW with several openings. He concluded that Eq. (1)

results in a conservative assessment of the lateral strength

comparing to the perforated wall. Based on the Purba [21]

results, Vian [19] proposed Eq. (2) to determine the lateral

strength of perforated SPSW.

Vop ¼ 1� 0:7D

Sdiag

� �Vp ð2Þ

Where Sdiag is shown in figure 1.

Moreover, Purba [21] reported that an individual perfo-

rated strip analysis can truthfully estimate the behavior of

SPSW without holes provided the DSdiag

� 0:6 be applied.

Eq. (2) is vastly used by designers despite its error.

Therefore, it should be modified that is done in this paper.

In the AISC [22] a capacity design method for SPSW has

been presented. The method assumes that all the infill plates

over the height of the wall will yield and plastic hinges will

form at the two ends of beams. The presence of holes in the

infill plates affects the stress in the boundary columns, thus

needing modifications to the current design method. Anjan

and co-workers [23] proposed Eq. (3) tcated SPSW, Vop.

Vop ¼ 0:5rtwLp;eff sin 2a ð3Þwhere tw is the infill plate thickness and r is the stress in

the infill plate tension strips, taken as the material yield

strength for design, the Lp,eff is the effective width of the

perforated infill plate. Also, the a (that is the angle of the

tension field) is calculated from CAN/CSA-S16-09 [24] or

AISC [25].

Moghimi [26] reported that SPSW’s column moment

demand may cause up to 20% with a perforation pattern.

This finding confirms the need to consider the specific

layout of holes rather than simply using a uniformly dis-

tributed stress with a value reduced from that of a solid

plate.

Mazzolani and co-workers indicated that, despite the

presence of holes, the a remains about 45� [27, 28].Vetr and co-workers [29] showed that an aluminum

perforated panel has a better yielding pattern than a per-

forated steel panel. They concluded that the aluminum

panel shows higher ductility and stiffness but lower lateral

strength. Based on the results, the designer can use alu-

minum or steel based on their aims in the design of per-

forated SPSW. Afshari [30] reported that the existing hole

on the compression diameter does not have considerable

effect on the angle of stress. Also, the hole in the mid-span

of the wall has a minimum effect on the SPSW behavior.

2. Method of study

Although perforated SPSW has been introduced as a cap-

able suggestion to improve SPSW behavior, the optimum

configuration of the system has not been investigated

comprehensively. In doing so, in this paper optimum con-

figuration of perforated SPSW is investigated. Therefore,

the configuration of perforated SPSW is investigated in

three aspects including; the effect of the number of the hole,

area of the hole in comparison with infill plate, and con-

figuration of perforated SPSW.

Investigation of the literature review shows that formulas

presented till now to calculate of shear strength of SPSW,

do not account for area ratio. It is caused to errors in the

calculation of shear strength. Therefore, the proposed for-

mula is presented for calculating the shear strength of

perforated SPSW in the case of area ratio.

3. Experimental study

3.1 Test set-up

Figure 2 shows the test setup and experimental geometries.

Based on the laboratory facilities, the pate with 600 9 600

mm was used for experimental testing. The models were

applied loading diagonally to make pure shear in the infill

plate. Four corners of the plate were attached to the

boundary frame by pin to make pined supported. The infill

plate thickness of the models is designed to 5mm. the infill

plate was bolted to the boundary frame. The boundary

frame was designed to resisting against stress imposed by

the infill plate. Also, the distances and diameter of bolts

were designed to prevent any nonlinear behavior at bolted

or preventing fracture of bolts.

Figure 1. Test specimen from Vian [19].

132 Page 2 of 17 Sådhanå (2021) 46:132

Page 3: On the design of perforated steel shear walls, an

3.2 Experimental results

Despite SPSW, the perforated SPSW is fully yielded, fig-

ure 3. The infill plate of SPSW does not yield completely.

In the other words, the infill plate does not contribute to the

absorption of energy due to imposed seismic energy.

The ultimate strength of SPSW was 189 kN. Results

showed that the capacity in perforated SPSW-1 (SPSW

with 4 holes) is reduced by around 50%. Also, the perfo-

rated model with 4 corner holes is reached to ultimate

strength in bigger displacement.

Figure 2. Test specimen.

Sådhanå (2021) 46:132 Page 3 of 17 132

Page 4: On the design of perforated steel shear walls, an

4. Numerical study

4.1 Numerical models

To investigate the effect of hole type on the seismic

behavior of SPSW, 25 FE models were analyzed. Table 1

illustrates the properties of the FE models. In this table, the

tw is the infill plate thickness. Also, D and Sdiag are the hole

diameter and distance between two-hole, respectively. The

sixth column of the table reports the ratio of the sum of hole

areas (Ahole) to the area of the infill plate (A plate). The A

plate is the area of the infill plate without the infill plate. In

the other words, the differences between Ahole and Aplate

measure the pure area of the infill plate.

The numerical models contain three parts. The first part

represents the type of SPSW as shown in figure 4. The

second part represents the infill plate thickness in mm. the

third part shows the presence of a hole on the infill plate.

For example, the S3-4-10 means the S3 model with an infill

plate of 4mm and the ratio of holes to the infill plate equals

10%.

4.2 Materials

The ST37 steel was used for FE models. For the steel, the

yield stress is 235 MPa and the ultimate stress is 370 MPa.

Also, the Yang modulus and Poison ratio for ST 37 is 200

GPa and 0.3 respectively. It should be noted, the stress-

Figure 3. The experimental model after testing.

Table 1. FE models properties.

Model tw (mm) D (mm) Sdiag D/Sdiag Ahole/Aplate

SPSW 4 – – – –

S1-4-10 4 35 63 0,56 0,10

S2-4-10 4 44 265 0,17 0,10

S3-4-10 4 52 127 0,41 0,10

S4-4-10 4 48 127 0,38 0,10

S5-4-10 4 62 201 0,31 0,10

S6-4-10 4 36 84 0,43 0,10

S1-4-10 4 35 63 0,56 0,10

S2-4-10 4 44 265 0,17 0,10

S3-4-10 4 52 127 0,41 0,10

S4-4-10 4 48 127 0,38 0,10

S5-4-10 4 62 201 0,31 0,10

S6-4-10 4 36 84 0,43 0,10

S1-4-20 4 48 63 0,76 0,20

S2-4-20 4 60 265 0,23 0,20

S3-4-20 4 70 127 0,55 0,20

S4-4-20 4 66 127 0,52 0,20

S5-4-20 4 84 201 0,42 0,20

S6-4-20 4 50 84 0,60 0,20

S1-4-30 4 61 63 0,97 0,30

S2-4-30 4 74 265 0,28 0,30

S3-4-30 4 89 127 0,70 0,30

S4-4-30 4 83 127 0,65 0,30

S5-4-30 4 105 201 0,52 0,30

S6-4-30 4 63 84 0,75 0,30

132 Page 4 of 17 Sådhanå (2021) 46:132

Page 5: On the design of perforated steel shear walls, an

strain curve of the materials was obtained from experi-

mental tests and then was introduced to ABAQUS. The

Von-Mises yield criterion, known to be the most suit-

able yield function for metals, is used in this research. The

type of hardening to be used in this simulation is isotropic

hardening. And also, the curve diagram is depicted in

figure 5.

4.3 Boundary condition

All FE models are analyzed under applied lateral loads as

pushover analysis. In so doing, pushover analysis with

displacement control was carried out. The ultimate

displacement was limited to a drift ratio of 0.025 per ASCE

7-16 [31].

In FE simulations, to consider the fixed support condition

at the end of columns, the degree of freedoms including

displacements and rotations in all directions were restricted.

Moreover, since the top beam of SPSW in real projects is

restrained from out of plane displacement, its degree of

freedom including out of plane displacement was restricted.

4.4 FE Modeling and validation of results

To modeling and analysis of FE models, the ANSYS pro-

gram was used. This software has a very good capability in

modeling and analysis of structures, especially steel struc-

tures. In the modeling, the shell element was used to model

the steel components. Both geometric nonlinear and non-

linear materials were considered for nonlinear analysis.

Also, to consider the nonlinear geometric analysis due to

initial defects and geometric defects, imperfection was

applied to it as a coefficient of buckling mode. Comparing

FE results with experimental results as shown in figure 6

reveals a good agreement between them.

4.5 Numerical results

4.5a Stress distribution in numerical models: figure 7

illustrates the von Misses stress for numerical models. In

S4, S5, and S6 models no nonlinear behavior in columns

occurs. In models S1 and S2, yield lines are formed hori-

zontally and vertically between the holes. In the S1 and S2

models, the horizontal and vertical stress distribution

between the holes is created, which practically creates an

Figure 4. The schematic view of holes in the SPSW.

Figure 5. Typical tensile curve for ST37 steel.

Sådhanå (2021) 46:132 Page 5 of 17 132

Page 6: On the design of perforated steel shear walls, an

incomplete diameter tension field. The whole infill steel

plate has not yielded and parts of it have remained elastic,

therefore the energy absorption capacity of the whole steel

plate is not used. Also, large stress has been created at the

bottom of the column, so in this case, the column is sus-

ceptible to plastic hinge formation. Besides, these models

are susceptible to plastic hinge formation at the panel zones

and the two ends of the beam. Although the formation of a

plastic hinge at the two ends of the beam is a desirable

yield, the yield of the panel zone is not desirable.

In the S3 model, yield lines are created with the steel

plate in line with the diameter of the tension field action.

The distribution of stress and expansion of steel plate yield

is better in this model than in S1 and S2 models, but the

panel zones and bottom of the columns of this model is

prone to plastic hinge formation that is not appropriate. In

the S4, S5, S6 models, the yield is limited to the steel plate,

and the column, beams, and panel zones are not affected by

the high stresses that lead to the formation of the plastic

hinge. The stress distribution and yield strength of the steel

sheet in the S6 model are wider than in the S4 and S5

models. In the S5 model, the stress distribution and sheet

yield are more limited to near the holes along the tensile

diameter, but in the S4 model, a better trend is observed.

Figure 8 shows the status of stresses multi-story models.

In the full steel shear wall model, the thickness on the first

and second story is 6 mm, and on the upper two floors, the

thickness of the steel sheet is 4 mm. In multi-story models,

it is not possible to use walls of the same thickness. But in

walls with successive holes, the infill plate thickness is

selected on all 6 mm stories. Because in the height of the

stories, the lateral shear force is reduced, the thickness of

the infill plate should be less, which is perforated walls,

instead of reducing the thickness of the infill plate, holes are

used. The status of the stress of structural components in

figure 7 shows that in a conventional wall (without hole), in

addition to the infill plate, a plastic hinge is formed in the

first and last story columns. Besides, the least surrender

occurs on the top story. Because if lower stories are yielded

before top stores, the possibility of the soft story is

increased. So, in the SPSW without the hole, the form of

the soft story is high possible but it is recused in perforated

SPSW.

4.5b Load displacement curve: The load drift and stiffness

curve are plotted in figure 9. Based on the results, the type

of perforated SPSW does not significantly affect the ulti-

mate strength of models. At drift around 0.4%, the stiffness

of perforated SPSW and SPSW coincide together. It means

that at a drift greater than 0.4%, the hole does have any

effect on the stiffness of models. For perforated SPSW, at a

drift greater than 0.1%, the hole does have any effect on the

stiffness of models.

The ultimate strength and stiffness of analyzed models

have been reported in table 2. Results indicate that perfo-

rated SPSW with a reduction of 20% in the area of infill

plate caused to 15% to 21% reduction in ultimate strength.

The S1 and S2 result in a minimum reduction in ultimate

strength and S5 and S6 result in a maximum reduction in

ultimate strength. The S1 and S2 result in maximum

reduction (35% to 38%) in elastic stiffness and S4 and S6

result in minimum (28% to 29%) reduction in elastic

stiffness. Unlike of ultimate strength, reduction in elastic

stiffness is more.

4.5c The effect of hole type on the imposed stresses tocolumns: The tension stress in the column during lateral

load is plotted in figure 10. Besides model S1-4-20, the hole

configuration does not considerable effect on the imposed

tension stresses to columns. But, utilizing the configuration

of the hole as model S1 reduces the tension stress up to drift

1%.

Unlike tensile stresses, model S1 does not suitable per-

formance in compressive stresses. The compression force in

-200

-150

-100

-50

0

50

100

150

200

-30 -20 -10 0 10 20 30

)N k(

daoL

Displacement (mm)

Experimental

FE

-100

-80

-60

-40

-20

0

20

40

60

80

100

-10 -5 0 5 10

)Nk(

daoL

Displacement (mm)

Experimental

FE

-150

-100

-50

0

50

100

150

-25 -20 -15 -10 -5 0 5 10 15 20 25

)N k(

daoL

Displacement (mm)

Experimental

FE

Figure 6. Comparison of FE results with experimental results.

132 Page 6 of 17 Sådhanå (2021) 46:132

Page 7: On the design of perforated steel shear walls, an

S1 and S2 models are almost like SPSW models, figure 11.

But, the compression column force is considerably reduced

in S3, S5, S6, and S6 models in comparison with SPSW.

The lower forces are created in models S5, S4, S6, and S3,

respectively. The reduction compression forces of the col-

umn for models S6 and S4 are almost close. Before drift

of0.3% to 0.6%, the compression forces of columns for S5,

S4, S6, and S3 are bigger than SPSW. Since in the range of

drift the wall experience of nonlinear behavior, the

increasing not important and can be ignored. It is also

confirmed for the bending moment as shown in figure 10.

4.5d The effect of area ratio on the compression forceimposed on the column: In figure 12, the created compres-

sion force in columns versus the drift ratio is plotted. This

figure shows that by increasing the hole are from 10% to

30% the compression force of the column reduced by 12%

for models S1 and S2. For other models, the compression

force of the column is reduced by only 2% to 3%. The

results indicated that besides models S1 and S2, the con-

figuration of the hole is more important than the area hole.

4.5e The effect of area ratio on the bending momentimposed to column: In figure 13, the created bending

moment in columns versus drift ratio is plotted. The fig-

ure shows that in the elastic zone, the configuration of the

hole does a significant effect on the bending moment of the

column. After adrift around 0.5%, the bending moment is

reduced in columns for all models. More effective is seen in

the S5 model. In these models, by increasing of hole area

from 10% to 30% the bending moment is reduced by 14%.

In the other models, the reduction is between 1% to 8%.

There, it is concluded that by perforated SPSW the bending

moment can be reduced maximum to 14%.

4.5f The effect of area ratio on the pushover curve: In the

previous sections, it showed the forces created (compres-

sion force and moment) in columns were dwindled up to

14% and 16%, respectively. In some models, the configu-

ration did not considerable impact on the reduction in

compression force and bending moment of the column.

Unlike the compression force and bending moment of the

column, the pushover curve of the model is affected by the

Figure 7. Distribution of stress in structural components.

Sådhanå (2021) 46:132 Page 7 of 17 132

Page 8: On the design of perforated steel shear walls, an

Figure 8. Distribution of stress in four-story structures.

132 Page 8 of 17 Sådhanå (2021) 46:132

Page 9: On the design of perforated steel shear walls, an

hole area, figure 14. The reduction of ultimate strength is

39%, 40%, 10%, 12%, 21%, and 21%, respectively, for S1,

S2, S3, S4, S5, and S6. Therefore, by increasing of area

hole the more reduction is made respectively in S1 and S2,

S5 and S6, S4, and S3. So, the configuration of S1 and S2 is

not suggested due to the high reduction of the ultimate

strength of SPSW.

4.5g Optimum configuration of perforated SPSWs: In the

previous sections, it showed the compression force and a

bending moment of the column are reduced maximum up to

14% and 16%, respectively. In some models, the configu-

ration did not considerable impact on the reduction in

compression force and bending moment of the column.

Unlike the compression force and bending moment of the

column, the pushover curve of the model is affected by the

hole area, figure 14. The reduction of ultimate strength is

39%, 40%, 10%, 12%, 21%, and 21%, respectively, for S1,

S2, S3, S4, S5, and S6. Therefore, by increasing of area

hole the more reduction is made respectively in S1 and S2,

S5 and S6, S4, and S3. So, the configuration of S1 and S2 is

not suggested due to the high reduction of the ultimate

strength of SPSW.

5. The proposed method to achieve the responsecurve of perforated SPSPW

The following equation is proposed to compute the ultimate

strength of perforated SPSW.

Vop ¼ Vpð1� 0:6D

Sdiag� 0:5

Ahole

AplateÞ ð4Þ

In table 3, the results of the proposed relation are com-

pared with Eq. (2). Results indicated that the proposed

relation has better agreement with FE results than Eq. (2).

To achieve the load-displacement curve of the perforated

SPSW, first, the load-displacement curve for the frame and

infill plate is measured separately. Then the measured

curves are summed together. An SPSPW is measured as a

separate frame (figure 15). The mentioned curve is obtained

(a) (b)

0

500

1000

1500

2000

2500

3000

3500

4000

0 0.5 1 1.5 2 2.5

Base

shea

r (KN

)

Dri� angle (%)

S6-4-20S5-4-20S4-4-20S3-4-20S2-4-20S-1-4-20

0

50

100

150

200

250

300

350

0 0.5 1 1.5 2 2.5

K (k

N/m

m)

Dri� angle (%)

S6-4-20

S5-4-20

S4-4-20

S3-4-20

S2-4-20

S-1-4-20

Figure 9. Comparing the response of the FE models with different hole pattern a) pushover curve, b) stiffness versus drift ratio.

Table 2. The ultimate strength.

Model Fu Fui/FuSPSW K (kN/mm) Ki/KSPSW

SPSW 4685,28 479,66

S1-4-20 3999,24 0,85 310,0477 0,65

S2-4-20 3992,56 0,85 302,2565 0,63

S3-4-20 3826,87 0,82 359,238 0,75

S4-4-20 3833,68 0,82 338,8559 0,71

S5-4-20 3682,88 0,79 360,9753 0,75

S6-4-20 3805,57 0,81 343,41 0,72

0

1000

2000

3000

4000

5000

6000

0 0.5 1 1.5 2 2.5

)NK(

nmuloc

n iecrof

no isneT

Dri� angle (%)

SSW

S6-4-20

S5-4-20

S4-4-20

S3-4-20

S2-4-20

S-1-4-20

Figure 10. The tension tress created on the columns due to

lateral loading.

Sådhanå (2021) 46:132 Page 9 of 17 132

Page 10: On the design of perforated steel shear walls, an

0100200300400500600700800900

0 0.5 1 1.5 2 2.5

)NK(

nmuloc

niecrof

noi serpmoC

Dri� angle (%)

SSWS6-4-20S5-4-20S4-4-20S3-4-20S2-4-20S-1-4-20 0

5

10

15

20

25

30

35

0 0.5 1 1.5 2 2.5

Bend

ing

mom

ent (

kN.m

)

Dri� angle (%)

SSWS6-4-20S5-4-20S4-4-20S3-4-20S2-4-20S-1-4-20

(a) (b)

Figure 11. The stress created on the columns due to lateral loading a) compression stress, b) bending moment.

0

1000

2000

3000

4000

5000

6000

0 0.5 1 1.5 2 2.5

Com

pres

ion

forc

e (k

N)

Dri� ra�o (%)

S1-4-30

S1-4-20

S2-4-10

0500

100015002000250030003500400045005000

0 0.5 1 1.5 2 2.5

Com

pres

ion

forc

e (k

N)

Dri� ra�o (%)

S2-4-30

S2-4-20

S2-4-10

0500

10001500200025003000350040004500

0 0.5 1 1.5 2 2.5

Com

pres

ion

forc

e (k

N)

Dri� ra�o (%)

S3-4-30

S3-4-20

S3-4-10

0500

10001500200025003000350040004500

0 0.5 1 1.5 2 2.5

Com

pres

ion

forc

e (k

N)

Dri� ra�o (%)

S4-4-30

S4-4-20

S4-4-10

0500

10001500200025003000350040004500

0 0.5 1 1.5 2 2.5

Com

pres

ion

forc

e (k

N)

Dri� ra�o (%)

S5-4-30

S5-4-20

S5-4-10

0500

10001500200025003000350040004500

0 0.5 1 1.5 2 2.5

Axia

l for

ce (k

N)

Dri� angle (%)

S6-4-30

S6-4-20

S6-4-10

Figure 12. Compression load versus drift curve.

132 Page 10 of 17 Sådhanå (2021) 46:132

Page 11: On the design of perforated steel shear walls, an

for each separated steel plate, and the frame, and then by

summing their effects, the overall curve is plotted.

In thin SPSW, at the first stage of loading, buckling

occurs. Therefore, yielding may occur after buckling of the

plate. The elastic shear buckling stress is:

scr ¼ Kv:p2:E

12:ð1� #2Þ ð5Þ

Kv ¼ 5:34þ 4

ðd=bÞ2d

b� 1

Kv ¼ 4þ 5:34

ðd=bÞ2d

b[ 1

8>><>>:

ð6Þ

Uwe ¼ scrG

þ 2rt

E:sin2h

� �d ð7Þ

where rt is the infill plate’s yielding stress, E is the Yang

modulus, G is the shear modulus, and h is the diagonal

tension field angle. Figure 16 illustrate the state of stresses

in the infill plate, before and after buckling that is as:

rxx ¼ rtysin2h ð8Þ

ryy ¼ rtycos2h ð9Þ

rxy ¼ ryx ¼ scr þ 1

2rtysin

2h ð10Þ

Thus, the shear force in the plate due to buckling is

0

10

20

30

40

50

0 0.5 1 1.5 2 2.5

)m .

Nk(tnemo

mgnidneB

Dri� ra�o (%)

S1-4-30

S1-4-20

S1-4-10

0

10

20

30

40

50

0 0.5 1 1.5 2 2.5

Bend

ing

mom

ent (

kN.m

)

Dri� ra�o (%)

S2-4-30

S2-4-20

S2-4-10

0

10

20

30

40

50

60

0 0.5 1 1.5 2 2.5

)m.

Nk(tnemo

mgnidneB

Dri� ra�o (%)

S3-4-30

S3-4-20

S3-4-10

0

10

20

30

40

50

60

0 0.5 1 1.5 2 2.5

Bend

ing

mom

ent (

kN.m

)

Dri� ra�o (%)

S4-4-30

S4-4-20

S4-4-10

0

10

20

30

40

50

60

0 0.5 1 1.5 2 2.5

)m.

Nk(tnemo

mgnidneB

Dri� ra�o (%)

S5-4-30

S5-4-20

S5-4-10

0

10

20

30

40

50

60

0 0.5 1 1.5 2 2.5

Bend

ing

mom

ent (

kN.m

)

Dri� angle (%)

S6-4-30

S6-4-20

S6-4-10

Figure 13. bending moment versus drift curve.

Sådhanå (2021) 46:132 Page 11 of 17 132

Page 12: On the design of perforated steel shear walls, an

Fwcr ¼ scr:b:t ð11ÞThe displacement corresponding to the plate’s buckling

under pure shear is Uwcr ¼ Fwcr=G. Using these shear and

buckling forces, and displacement, the shear force-dis-

placement curve of the plate is plotted as shown in fig-

ure 17. For simplicity, lines OC and CD are substituted by

line OD. Researchers confirmed that such a change has a

small effect on the predicting behavior of SPSW [18].

Considering the von Misses criterion, if Eq. (12) be

satisfied, the infill plate will yields.

ðrxx � ryyÞ2 þ ðrzz � ryyÞ2 þ ðrxx � rzzÞ2þ 6 sxy

2 þ sxz2 þ syz

2� �

¼ 2Fy2 ð12Þ

Considering the infill plate as plane stresses results:

rz ¼ ryz ¼ rxz ¼ 0 ð13ÞTherefore

rx2 þ ry

2 � 2rxry2 þ 3sxy

2 ¼ Fy2 ð14Þ

By considering all stresses (buckling and yielding) and

substituting the stress values, it results:

3scr2 þ 3scrrtsin2hþ rt

2 � Fy2 ¼ 0 ð15Þ

Thus, the equivalent yielding stress of the plate is given:

rt ¼ 1:5scrsin2h�ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffið1:5scrsin2hÞ2 � ð3scr2 � Fy

2Þq

ð16Þ

0

1000

2000

3000

4000

5000

0 0.5 1 1.5 2 2.5

Base

shea

r (kN

)

Dri� ra�o (%)

S1-4-30

S1-4-20

S1-4-100

1000

2000

3000

4000

5000

0 0.5 1 1.5 2 2.5

Base

shea

r (kN

)

Dri� ra�o (%)

S2-4-30

S2-4-20

S2-4-10

0

1000

2000

3000

4000

5000

0 0.5 1 1.5 2 2.5

Base

shea

r (kN

)

Dri� ra�o (%)

S3-4-30

S3-4-20

S3-4-10

0

1000

2000

3000

4000

5000

0 0.5 1 1.5 2 2.5Ba

se sh

ear (

kN)

Dri� ra�o (%)

S4-4-30

S4-4-20

S4-4-10

0500

10001500200025003000350040004500

0 0.5 1 1.5 2 2.5

Base

shea

r (kN

)

Dri� ra�o (%)

S5-4-30

S5-4-20

S5-4-10

0

1000

2000

3000

4000

5000

0 0.5 1 1.5 2 2.5

Base

shea

r (KN

)

Dri� angle (%)

S6-4-30

S6-4-20

S6-4-10

Figure 14. Load displacement curve.

132 Page 12 of 17 Sådhanå (2021) 46:132

Page 13: On the design of perforated steel shear walls, an

By ignoring of buckling capacity of the infill plate and

accounting for the hole effect on lateral strength of the infill

plate and, its shear strength will obtain as:

Fwu ¼ t:Fy sin 2h2

ð1� 0:6D

Sdiag� 0:5

Ahole

AplateÞ ð18Þ

In this formula, it can be assumed h = 45� that yield

sin 2h ¼ 1.

The shear plastic displacement of infill, Dwp, is obtained

by equating the work of the shear force to the strain energy

of the plate (U).

U ¼ZZZ

1

2Eðrx2 þ ry

2 � 2#rxryÞ þ 1

2Gsxy

2

� �dxdydz

ð19Þ

Table 3. Comparison of the proposed formula with FE results.

Model Vop (FE) Vop- Eq. (4) error of Eq. (4) Vop-Eq. (4) error of Eq. (4)

SPSW 4685.28 – – – –

S1-4-10 4470.67 2848.65 36.28 2876.76 35.65

S2-4-10 4470.67 4127.732 7.67 3973.12 11.13

S3-4-10 4145.98 3340.605 19.43 3298.44 20.44

S4-4-10 4152.76 3438.996 17.19 3382.77 18.54

S5-4-10 4116.49 3668.574 10.88 3579.55 13.04

S6-4-10 4134.4 3275.011 20.79 3242.21 21.58

S1-4-20 3999.24 2192.711 45.17 2080.264 47.98

S2-4-20 3992.56 3930.95 1.54 3893.468 2.48

S3-4-20 3826.87 2881.447 24.70 3443.681 10.01

S4-4-20 3833.68 2979.838 22.27 3485.848 9.07

S5-4-20 3682.88 3307.808 10.18 3626.407 1.53

S6-4-20 3805.57 2717.462 28.59 3373.402 11.36

S1-4-30 3498.00 1503.975 57.00 2619.07 25.13

S2-4-30 3498.00 3766.965 -7.69 3588.92 -2.60

S3-4-30 3408.26 2389.493 29.89 2998.58 12.02

S4-4-30 3541.4 2553.478 27.90 3068.86 13.34

S5-4-30 3476.19 2979.838 14.28 3251.58 6.46

S6-4-30 3446.01 2225.508 35.42 2928.30 15.02

Figure 15. Assuming a separate frame.

Figure 16. Conditions of stresses in the steel shear wall.

Sådhanå (2021) 46:132 Page 13 of 17 132

Page 14: On the design of perforated steel shear walls, an

Disregarding the buckling strength of the plate,

rx ¼ rtcos2a ð20Þ

ry ¼ rtsin2a ð21Þ

sxy ¼ 0:5rtsin2a ð22ÞFinally, the strain energy is attained.

U ¼ 1

2Ert

2cos4aþ rt2sin4a� 2#rt

2cos2asin2a� �þ 1þ #

4Ert

2sin2a

� �b:d:t

ð23ÞWith Poisson’s ratio= 0.3 and using the trigonometric

relations, Eq. (23) is shortened as:

U ¼ 1:3rt2

8E3þ sin22a� �

bdt ð24Þ

Equaling the external work (W ¼ FwDw) to the strain

energy is resulted in the shear displacement (Dwp).

Dwp ¼ 0:65rtE

3þ sin22hsin2h

d ð25Þ

If h ¼ 45, the Dwp will be 1:95rtE d.

The elastic stiffness of the frame is expressed as

Kf ¼ 24Ec

h312qd þ 1

12qd þ 4ð26Þ

displacement curve of frame, qd ¼ Ibd4Icd

, and IbdandIcd are,

respectively, the moments of inertia of the beam and col-

umns sections.

The frame’s shear force obtained after the formation of

plastic hinges in the columns, Ff , represents the shear

capacity or the ultimate shear force. Displacement Df cor-

responds to the frame’s elastic limit displacement (onset of

plastic displacement) and is equal to:

Df ¼ bMpd

2

6EIcð27Þ

Ff ¼ 4Mfu

dð28Þ

The load-displacement curve of frame, as shown in fig-

ure 18, is obtained from Eqs. (27) and (28).

In Eq. (27) the b assumed equals 1.5. This confection

was obtained by fitting in FE results. By Eqs. (18), (25),

(27), and (28), the load-displacement diagram of the SPSW

ones are drawn.

6. Accuracy of proposed formulas

In this section as shown in figure 19, to evaluate the

accuracy of the proposed relationships, the pushover curve

obtained from the proposed relationships is compared with

Figure 17. The shear load-displacement diagram of the plate

[18].

Figure 18. Requirement properties for sketch load-displacement of frame.

132 Page 14 of 17 Sådhanå (2021) 46:132

Page 15: On the design of perforated steel shear walls, an

the FE results. According to this figure, the proposed

relations in the elastic region correspond to the results of

the FE. Therefore, it predicts this zone with very good

accuracy. Also, in the inelastic zone, an error of less than

8% is observed, which indicates that the proposed rela-

tionships are of acceptable accuracy.

7. Conclusions

In the present paper, the behavior of perforated SPSW was

investigated experimentally and numerically. Based on the

numerical and experimental results, optimumperforated SPSW

was proposed.Also, a formulawas presented to calculate lateral

shear strength. The results are summarized as follows:

0

1000

2000

3000

4000

5000

6000

0 20 40 60 80

Base

shea

r (kN

)

Displacement (mm)

S4-6-10 Wall

Plate Frame0

500

1000

1500

2000

2500

3000

3500

4000

4500

0 20 40 60 80

Base

shea

r (kN

)

Displacement (mm)

S4-4-10 Wall

Plate Frame

0500

100015002000250030003500400045005000

0 20 40 60 80

Base

shea

r (kN

)

Displacement (mm)

Wall Plate

Frame S4-6-200

500100015002000250030003500400045005000

0 20 40 60 80

Base

shea

r (kN

)

Displacement (mm)

Wall Plate

Frame S4-6-20

0500

10001500200025003000350040004500

0 20 40 60 80

Base

shea

r (kN

)

Displacement (mm)

S4-6-30 Wall

Plate Frame0

500

1000

1500

2000

2500

3000

3500

4000

0 20 40 60 80

Base

shea

r (kN

)

Displacement (mm)

S4-4-30 WallPlate Frame

Figure 19. Comparison of pushover curve with the proposed model.

Sådhanå (2021) 46:132 Page 15 of 17 132

Page 16: On the design of perforated steel shear walls, an

• The configuration of perforated SPSW does not

significantly affect the ultimate strength of the system.

Therefore, the proposed formula can be used for all

types of perforated SPSW.

• At drift around 0.4%, the stiffness of perforated SPSW

and SPSW coincide together. For perforated SPSW, at

drift greater than 0.1%, the hole type does have any

effect on the lateral stiffness.

• In the elastic zone, the configuration of the hole does a

significant effect on the bending moment of the

column. After adrift around 0.5%, the bending moment

is reduced in columns for all models. More effective-

ness is seen in the S5 model. In these models, by

increasing of hole area from 10% to 30% the bending

moment is reduced by 14%. In the other models, the

reduction is between 1% and 8%. Therefore, it is

concluded that by perforated SPSW the bending

moment can be reduced maximum to 14%.

• Perforated SPSW with a reduction of 20% in infill

plate area cause to 15% to 21% reduction in ultimate

strength. The S1 and S2 result in maximum reduction

(35% to 38%) in elastic stiffness and S4 and S6 result

in minimum (28% to 29%) reduction in elastic

stiffness. Unlike of ultimate strength, reduction in

elastic stiffness is more.

• The hole type does not have considerable effect on the

imposed tension stresses to columns. But, utilizing the

configuration of the hole as model S1 reduces the

tension stress up to drift 1%. Unlike tensile stresses,

model S1 does not suitable performance in compres-

sive stresses.

• The lower compression forces are created in models

S5, S4, S6, and S3, respectively. The reduction

compression forces of the column for models S6 and

S4 are almost close. Before drift of0.3% to 0.6%, the

compression forces of columns for S5, S4, S6, and S3

are bigger than SPSW. Since in the range of drift the

wall experience of nonlinear behavior, the increasing

not important and can be ignored.

• By increasing of hole area from 10% to 30% the

compression force of the column reduced by 12% for

models S1 and S2. For other models, the compression

force of the column is reduced only 2% to 3%. The

results indicated that besides models S1 and S2, the

configuration of the hole is more important than the

area hole.

• Reduction of ultimate strength is 39%, 40%, 10%,

12%, 21%, and 21%, respectively, for S1, S2, S3, S4,

S5, and S6. Therefore, by increasing of area hole the

more reduction is made respectively in S1 and S2, S5

and S6, S4, and S3. So, the configuration of S1 and S2

is not suggested due to the high reduction of the

ultimate strength of SPSW.

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Sådhanå (2021) 46:132 Page 17 of 17 132