ORIGINAL ARTICLE

Tensile load capacity analysis of perforated reinforcementsheet

Kay Wille • Nguyen Viet Tue

Received: 29 August 2012 / Accepted: 20 August 2013

� RILEM 2013

Abstract Research was conducted to develop, ana-

lyze and optimize a novel composite element consist-

ing of a perforated reinforcement sheet embedded in

self consolidating fiber reinforced concrete (SC-FRC).

Experimental results of the optimized composite

showed that SC-FRC and the reinforcement sheet act

synergistically, which leads to an enhanced material

utilization. The research in this paper focuses only on

the reinforcement sheet and its optimization supported

by a finite element parametric study. A semi-mechan-

ical model was derived to describe the load bearing

capacity of an embedded reinforcement sheet under

biaxial loading. The semi-mechanical model is based

on the mechanical behavior of an infinitive sheet with

centered opening. Direct tension tests of the concrete-

steel composite as well as tension tests of the non-

embedded sheet were performed to experimentally

verify the proposed model.

Keywords Reinforcement sheet � Perforation �Composite � Concrete

1 Introduction

In the design of reinforced concrete it is common to

place reinforcing bars (rebars) in two layers to provide

a biaxial load carrying capacity, e.g. for an upper

bridge deck construction. The localized rebar rein-

forcement can be evenly distributed by a novel

reinforcement sheet made out of the same material.

The comparison of both reinforcement elements with

the same load carrying capacity in the main directions

shows that a reduction in height is achievable, which

particularly allows the sheet to be applied for very thin

composites, built from concrete and steel (Fig. 1). The

reinforcement sheet, which is about 1 mm (0.04 inch)

thick and 5 mm (0.2 inch) in height, provides high

load carrying capacity in both directions. Therefore

the minimum reinforcement requirement to resist

biaxial loading can be fulfilled with only one layer,

which could potentially save expensive material and

time to place. The novel reinforcement sheet, to be

embedded in concrete, could be potentially applied in

thin structural elements such as pipes or shells, in

elements subjected to biaxial loading such as, slabs,

tunnel linings or upper bridge deck constructions, as

confinement in concrete columns, as shear reinforce-

ment or in very thin structures, where the use of

conventional reinforced concrete is either not cost

effective or completely in-feasible.

The development of a novel cementitious compos-

ite construction, built from concrete or fiber reinforced

concrete and steel sheet reinforcement, is reported in

K. Wille (&)

University of Connecticut, Storrs, CT, USA

e-mail: kwille@engr.uconn.edu

N. V. Tue

Graz University of Technology, Graz, Austria

e-mail: tue@tugraz.at

Materials and Structures

DOI 10.1617/s11527-013-0169-3

[6]. The dissertation [6] comprises (a) the develop-

ment of the sheet reinforcement, (b) the design of self-

consolidating concrete (SCC) and its interaction with

the sheet in the fresh concrete state, (c) the experi-

mental and computational investigation of the bond

behavior between both materials, including the design

and implementation of a three dimensional smeared

crack constitutive concrete model, and (d) the inves-

tigation with ultra-high performance fiber reinforced

concrete as composite partner. The research goal was

to tailor the design of the sheet reinforcement, the

material properties of the concrete and their bond

behavior for optimized structural performance. In

order to improve the quality and flexibility of the

casting method it is reasonable to embed the perfo-

rated sheet in SCC (Fig. 2). Perforation in the

reinforcement sheet enables the SCC to flow through

and enclose the sheet. The larger the area fraction of

the perforation is, the less brutto sheet material is

utilized. Therefore, the minimum diameter of a

perforation, or hole, is set by the flow and blocking

behavior of the SCC.

Bending (Fig. 3) and direct tensile tests of the

sheet-concrete composite showed a delamination of

the composite at 60 % of the theoretical load carrying

capacity [6]. A finite element (FE) analysis was

carried out in order to investigate the inefficient bond

behavior. Significant increase in load carrying capac-

ity was obtained by adding steel fibers to the concrete.

This led to a composite consisting of a steel sheet and

self consolidating fiber reinforced concrete (SC-FRC),

which acts synergistically to resist applied loads. This

synergistic effect is a result of the fiber orientation

(Fig. 4), which followed the flow direction of the

concrete. The flow of the concrete was designed in

conformance with the principle tensile stress direc-

tions leading to enhanced load carrying behavior.

Further information about the hybrid construction

consisting of ultra-high performance fibre reinforced

concrete and perforated steel sheet reinforcement is

provided in [6, 5].

(a)

(b)

Fig. 1 Comparison of two layers of conventional reinforce-

ment with one layer of sheet reinforcement with the same load

carrying capacity in the main directions

Fig. 2 Casting with self consolidating concrete of normal (left) and ultra high strength (right)

Materials and Structures

This paper focuses on the design of the sheet

reinforcement and on the development of a semi-

mechanical model to describe its biaxial load bearing

capacity. Further information about the interaction

between concrete in the fresh and hardened state as

well as the effect of fiber reinforcement is left for

future publications.

2 Sheet requirements

An efficient interaction between reinforcement sheet

and concrete requires a sufficient bond between the

two components. This led to the design of holes with

bulging edges produced by mechanical deformation.

This concept had been mentioned in a preliminary

Fig. 3 Delamination of non-fiber reinforced sheet-concrete composites and no delamination of fiber reinforced sheet-concrete

composites subjected to bending [6] (slab thickness = 6 cm)

Fig. 4 Fiber distribution and orientation influenced by the reinforcement sheet [6]

Materials and Structures

research study by Mucha [3]. The circular shape of the

holes, punched in the sheet, prevents stress peaks and

guarantees a continuous biaxial force path. The

minimum diameter of the holes is determined by the

flow behavior of the concrete to prevent segregation

and blocking.

The load bearing capacity of the sheet is influenced

by the tensile strength of the material, by the

perforation system and by its thickness. The perfora-

tion system (Fig. 5), defined by the placement of the

holes, the hole distance a, the hole diameter dh and the

bulging height hb, plays an important role in sheet

effectiveness.

It is desirable to design a perforation system

with a simple symmetry to minimize production

costs and to ease splicing of reinforcement. Fur-

thermore, it is necessary to avoid large crack widths

caused by bondless areas. A shifted perforation

system, as shown in Fig. 1, fulfills the basic

requirements. Besides large bulging holes, small

bulging holes are integrated in the perforation

system to ease the air release of the concrete and

to enhance the sheets bending stiffness to facilitate

the handling during transportation and placement.

The lines of large bulging holes and small bulging

holes provide high and low bending stiffnesses,

respectively, which is illustrated through solid and

dashed lines in Fig. 6.

The main goal is to design the geometry of the sheet

with regard to the best material utilization considering

the requirements mentioned above.

3 Geometry and placement of perforations

Thickness The thinner the sheet, the easier it is to

manufacture. Furthermore, the weight per unit area is

reduced which facilitates the placement on-site. On the

other hand, the maximum tensile resistance decreases

proportionally with thickness reduction and the mate-

rial cost per unit weight increases. Therefore, the

thickness was set in the range from t = 0.75 mm (0.03

inch) to t = 2.0 mm (0.08 inch). Experimental tests

and FE calculations include sheets with t = 0.75 mm

(0.03 inch) to t = 1.0 mm (0.04 inch).

Hole diameter From an economical point of view,

the target is to minimize the diameter to maximize the

sheet net area, thus maximizing the material utiliza-

tion. For preliminary tests, the diameter was set to

40 mm (1.63 inch), which is 2.5 times the maximum

aggregate size of 16 mm (0.63 inch), to ensure

sufficient bond and facilitate casting with SCC.

Bulge geometry Bulging of the hole edge provides a

support for the compression strut, thus providing the

bond between sheet and concrete. A smooth bulge

gradient facilitates stress shifting in the bulged sheet

areas, enhancing the utilization of the material.

Furthermore, concentrations of plastic deformation

during production are avoided.

Orientation of perforations Generally, the perfora-

tion system can be placed parallel or with an angle of

45� to the principle tensile stress (Fig. 6). The 45�placement is preferable to minimize large crack widths

caused by weak bond lines.

Fig. 5 Definition of the perforation system

Materials and Structures

4 Load bearing behavior

Based on the biaxial material behavior of an ideal

elastic-plastic material, the stress distribution of an

infinite sheet with a centered hole under biaxial

loading is derived. This provides the mechanical basis

for the developed semi-mechanical model to describe

the load bearing capacity of a perforated sheet. The

semi-mechanical model was developed with the

support of the FE software SOFiSTiK [2] (Fig. 7).

4.1 Material

Within this research program, two different types of

steel (low strength—DC01 and high strength—

H420LA) were used to manufacture the perforated

reinforcement sheet (Fig. 8). Their material behavior

obtained through standardized tensile tests in accor-

dance with DIN EN 10002-1 [1] were assigned in the

FE calculation.

Due to the perforation, a biaxial stress state is

present in the reinforcement sheet subjected to load.

The definition of yield stress rf follows the VON MISES

yield criterion.

4.2 Infinite sheet with a hole

Uniaxial loading An uniform loading, p, in the x-

direction applied to an infinite sheet with a thickness

(a) (b)

(c) (d)

Fig. 6 Perforation symmetry with reduced and increased hole distance and overlayed secondary symmetry of small holes, parallel and

with an angle of 45� to the principle axes; including lines with high (solid) and low (dashed) bending stiffness of the sheet

Materials and Structures

h leads to a constant stress state with rx = p/

h, ry = 0, and s = 0. The inclusion of a circular

hole with a radius rh changes the constant stress state

and leads to a stress peak at the edge of the hole. By

transforming stresses into in a polar coordinate system

with an angle u and a distance from the center of the

hole r, the stress state can be described by Equations

1–3, where rr and ru are the radial and tangential or

circumferential stresses, and sru is the shear stress [4].

rr ¼p

2h1� rh

2

r2þ 1� 4rh

2

r2þ 3rh

4

r4

� �cos 2u

� �ð1Þ

ru ¼p

2h1þ rh

2

r2� 1þ 3rh

4

r4

� �cos 2u

� �ð2Þ

sru ¼p

2h�1� 2rh

2

r2þ 3rh

4

r4

� �sin 2u ð3Þ

Equation 3 shows that with u ¼ 0� or u ¼ 90� the

shear stress sru ¼ 0 and thus, the radial and tangential

stresses are principle stresses. The highest stress can

be found tangential to the edge of the hole in loading

direction. Tangential stress ru at u ¼ 90� and r = rh

equals three times the stress obtained on a sheet

without a hole. The distribution of radial and tangen-

tial stresses of an infinite sheet under uniaxial loading

is included in Fig. 9c (px = 1, py = 0).

Biaxial loading The analytical derivation of the

elastic stress distribution of an infinite sheet with a

hole under biaxial loading is achieved through the

superposition of the stress states caused by loading in

x- and y-direction px and py. The superimposed stress

state is given with Eqs. 4–6.

rrðuÞ ¼ rrxðuÞ þ rry

ðu� 90�Þ ð4Þ

Fig. 7 Stepwise

development of a semi-

mechanical model

describing the material

behavior of perforated

sheets

Fig. 8 Uniaxial tensile behavior of steel used (DC01 and

H420LA)

Materials and Structures

(a) (b)

(c) (d)

(e)

Fig. 9 Theoretical quantitative distribution of tangential and radial stresses of an infinite sheet with a hole at an angle of 0� and 90� in

the elastic state under different biaxial loading ratios

Materials and Structures

ruðuÞ ¼ ruxðuÞ þ ruy

ðu� 90�Þ ð5Þ

sruðuÞ ¼ sruxðuÞ þ sruy

ðu� 90�Þ ð6Þ

The quantitative distribution of stresses at an angle of

u ¼ 0� or u ¼ 90� under different biaxial loading

ratios py/px is summarized in Fig. 9. There it can be

seen that the stresses at r & 3rh approach the stresses

obtained on a sheet without a hole. The lowest peak

stress (two times the stress on a sheet without a hole) is

caused by a biaxial loading ratio of py/px = 1. The

maximum peak stress (four times the stress on a sheet

without a hole) is caused by a biaxial loading ratio of

py/px = - 1.

In the next step, the stress states at an angle of

u ¼ 45� need to be calculated considering the shifted

perforation symmetry of the reinforcement sheet

(Fig. 10). Through superposition of the stress states

caused by px and py, Eqs. 7–9 were derived to describe

normal and shear stresses at an angle of 45�. Their

distribution is shown in Fig. 11.

rr ¼px þ py

2h1� r‘

2

r2

� �ð7Þ

ru ¼px þ py

2h1þ rh

2

r2

� �ð8Þ

sru ¼px � py

2h�1� 2rh

2

r2þ 3rh

4

r4

� �ð9Þ

In addition to the normal and shear stresses, Fig. 11

includes the distribution of the calculated principle

stresses r1 and r2, as well as their direction expressed

by the angle a (Eq. 10). Equation 10 is derived based

of stress transformation and from Eqs. 7, 8 and 9.

a ¼ 45� 1

2arctan

1� x

1þ x� r2

r2h

þ 2� 3r2

h

r2

� �� �

where x ¼ py=px

ð10Þ

A biaxial loading ratio of py/px = 1 results in surðrÞ ¼0; aðrÞ ¼ 45� and thus, ruðrÞ ¼ r1ðrÞ as well as

rr(r) = r2(r). Decreasing the loading ratio leads to an

increase in the asymptotic value of the shear stress.

This influences the direction and magnitude of the

principle stresses. A biaxial loading ratio of py/

px = - 1 results in a stress state with only shear

stress. The principle stresses at the considered angle of

u ¼ 45� follow the direction of the load applied and

are less than or equal to the stresses at an angle of

u ¼ 0� or u ¼ 90�:

4.3 FE model

The FE method is used to study the stress flow in the

perforated sheet beyond the elastic range. By utilizing

biaxial symmetry of the perforation pattern, the

smallest possible sheet unit was selected for investi-

gation under different biaxial loading ratios (Fig. 12).

Bilinear, non conform, four-node shell elements

(QUADs) were used and generated by an automatic

mesh generator. An elastic plastic material behavior

was assigned in accordance with the yield stress

experimentally obtained.

The biaxial loading is achieved by a controlled

application of displacement in the x- and y-directions.

A global uniaxial loading in the x-direction is obtained

by linking the y-displacement across section B

(Fig. 12). This forces all nodes in section B to displace

equally in the y-direction. If this linking boundary

condition had not been assigned, the calculation would

have represented a sheet section at the edge, which is

not influenced by the in-plane action of the continu-

ative reinforcement sheet.

The failure criterion of the sheet follows a strain

approach. A failure was defined when locally the

principle strain value exceeds 10 %. Bulging of the

edge, influences of the second and third order theory,Fig. 10 Infinite sheet under biaxial loading

Materials and Structures

(a) (b)

(c)(d)

(e)

Fig. 11 Theoretical quantitative distribution of normal, shear, and principle stresses and direction of the 1st principle stress of an

infinite sheet with a hole, evaluated at an angle of 45� to the loading direction in the elastic state under different biaxial loading ratios

Materials and Structures

and strain-hardening material behavior are not con-

sidered for the following analysis.

4.4 Failure behavior

The stress distribution of a biaxially loaded perforated

sheet is comparable with a one hole sheet (Fig. 9). As

long as the perforated sheet is in an elastic state, the

maximum principle strain occurs tangential to the

edge of the hole at an angle of u ¼ 90� to the main

loading direction (x-direction) [Fig. 13a (px = py)].

As the loading increases, the material starts locally to

plasticize. The decrease in local stiffness leads to

stress shifting to areas with higher stiffness (Fig. 13b).

The plastification continues by spreading along the

edge of the hole and leading to a failure line with an

angle of 45� (Fig. 13c), which was confirmed by

experimental investigation and defined as the failure

section (see Fig. 12).

Perforating a plain sheet results in a lower

extensional stiffness and an non-uniform stress distri-

bution. This leads to plastifications at lower global strain

values, which results in a pronounced non-linear

behavior (Fig. 14a). Increasing the hole distance a and

reducing the hole diameter dh, will cause the perforated

sheet to approach the sheet without hole (Fig. 14b).

The two geometric parameters, hole diameter dh

and hole distance a, determines the load carrying

behavior of the perforated sheet. By defining the

parameter ‘n/2rh, the two parameteric dependency of

the perforated sheet’s load carrying behavior can be

transformed in a single parametric dependency

(Fig. 15). Therefore, the dominant parameter ‘n/2rh

is included in the semi-mechanical model of biaxial

loaded perforated sheets.

4.5 Parameter and model approach

Figure 16 summarizes the semi-mechanical model to

describe the load bearing capacity of biaxially loaded

perforated sheets. The ratio of principle stresses

g = r2/r1 along the failure section is determined by

the ratio of the resultant forces x = Ry/Rx applied. The

maximum principle stress r1,max can be calculated by

considering VON MISES yield criterion and the exper-

imentally obtained uniaxial yield stress rf. The ratio of

principle stresses g along the failure section is

variable. This influences the distribution of principle

stress r1 (Fig. 16), which is considered by the

coefficient ar. The product ar;1 � r1;max equals in the

equivalent mean principle stress r1; where a is the

angle between the stress vector and the x-axis. The

obtained principle stresses (r1; r2; a) are transformed

by rotation into a coordinate system normal to the

failure section, defined by h = 45� to the x-axis. The

integration of the normal stress rg and the shear stress

Fig. 12 Sheet geometry and simulated sheet section without considering bulging and the small hole in the failure section

Materials and Structures

sng over the net area of the failure plane (‘n 9 h) leads

to the normal and shear force resultants N and

Q. Vector decomposition of these force resultants

determines the maximum load bearing capacity in x-

and y-direction.

(a)

(b)

(c)

Fig. 13 Principle strain e1 in % with overlapping direction

vectors, py/px = 1, and hole distance a = 6 cm

(a)

(b)

Fig. 14 Tensile behavior of perforated sheets as a function of

hole distance a and hole diameter dh

Fig. 15 Single parameter illustration of the maximum of

normalized stress and of the normalized elastic modulus

Materials and Structures

4.6 Parameter determination

With regard to the model, the parameter g = r2/

r1, a, and the coefficients ar,1, ar,2 are dependent on

the ratio of the resultant forces x = Ry/Rx and the

relative net length ‘n/2rh. The net length ‘n is calculated

by Eq. 11. Assuming a hole radius of rh = 20 mm the

net length for the investigated hole distances

a = 40, 60, 100 mm are 16.6, 44.9 and 101.4 mm.

‘n ¼ffiffiffi2p

a� 2r‘ ð11ÞThe ratio of principle stresses g increases with

increasing x = Ry/Rx and increasing ‘n in the elastic

state as well as in the plastic state (Fig. 17).

‘n approaching1 represents an unperforated sheet,

where g is defined by g(Ry/Rx) = Ry/Rx. As ‘n

approaches 0, the holes are in contact. Therefore,

g = 0 if Ry/Rx = 1. Considering these boundary

conditions, g(x, ‘n) is defined by Eq. 12.

a, the angle between the 1st principle stress vector

and the x-axis, increases with increasing x = Ry/Rx

and decreasing ‘n in the elastic state as well as in the

plastic state (Fig. 18).

As ‘n approaches 0, a approaches 45� independent

of Ry/Rx (Fig. 11). As ‘n approaches1; a approaches

0� representing an unperforated sheet. Based on

Eq. 10 the Eq. 13 was derived considering these

boundary conditions.

The coefficient ar,1 of the principle stress r1 can be

considered to be independent of Ry/Rx and ‘n in the

plastic state and is defined by ar,1 = 0.98 (Eq. 14).

ar,2, the coefficient for calculating the mean principle

stress r2; decreases with increase of Ry/Rx. Equa-

tion 15 represents a best fit curve.

g ¼ 1

4exp �0:9

‘n

2rh

� �1:1" #

ðxþ 1Þ2

þ exp �0:68=‘n

2rh

� �0:7" #

ðxþ 1Þ � 1

ð12Þ

Fig. 16 Model to calculate the maximum load bearing capacity

Fig. 17 Ratio of principle stresses g in the failure section in the

plastic state

Materials and Structures

a ¼ 45� 1

2arctan

1� x

1þ x

� �0:8

�1:9 ‘n

2rh

� �0:2" #

ð13Þ

ar;1 ¼ 0:98 ð14Þ

ar;2 ¼ �0:055x2 � 0:12xþ 0:91 ð15Þ

The maximum load bearing capacity of a perforated

sheet with different net lengths ‘n and under different

loading ratios is shown in Fig. 19. The results obtained

through the semi-mechanical approach (including

Eqs. 11–15) are compared with the results obtained

through FE-calculation. The calculated capacity of the

reinforcement sheet is confirmed by experimental test

results.

4.7 Further parametric study

A further parametric study was conducted in [6]. This

included the overlapping of a small hole system with

an additional hole in the failure section, strain-

hardening material behavior and bulging of the hole

edges. It can be concluded that the inclusion of a small

hole in the failure section leads to a reduction of the net

length and thus, to a proportional reduction in the

maximum load bearing capacity. Considering strain-

hardening material behavior increases the maximum

load bearing capacity of the sheet. However, due to the

uneven stress distribution in the failure section, the

increase in load bearing capacity is lower than the

uniaxial strain-hardening effect. Hole edge bulging

causes a shift of the sheet’s center of gravity out of the

sheet plane. As a result, in-plane axial loading causes

an additional bending moment, which is controlled by

the out-of-plane boundary conditions. Embedding the

Fig. 18 Angle a in failure section in plastic state

Fig. 19 Verification of the model approach

(a) (b)

(c)

Fig. 20 Prediction of tensile response of a perforated sheet,

considering non-linear material behavior and third order theory

(3.OT)

Materials and Structures

sheet in concrete will minimize additional bending

moments in the sheet and maintain the load bearing

capacity of the sheet. A bulging height of up to 5 mm

is still small enough to utilize the material in the

bulging area through stress shifting.

4.8 Reinforcement sheet: tension test

Figure 20a shows a section of a bulged perforated

reinforcement sheet under tension. The results of the

FE-model in comparison with the experimentally

obtained tensile curve are summarized in Fig. 20c.

The failure mode of a non-embedded, and thus, non-

constrained, sheet is characterized by an elongation of

the hole geometry including an axial force adopted

deformation of bulged hole edges. This leads to a

minimization of local bending moments in the sheet.

Because of these large deformations, stress redirection

caused by the holes is reduced significantly. Thus, the

angle of the failure section h decreases from 45� to 0�and the material is completely utilized over the entire

cross section. Prediction of the experimental results

considering the influence of the third order theory

(3.OT) leads to a significant increase in the load-

bearing capacity in comparison to the non-linear FE-

calculation without considering 3.OT. A much stiffer

behavior is obtained by considering the boundary

conditions of an embedded reinforcement sheet.

Fig. 21 Direct tension test with embedded reinforcement sheet

(a)

(b)

Fig. 22 Direct tension test results in comparison to the semi-

mechanical model approach

Materials and Structures

Direct tension tests with embedded sheet reinforce-

ment have also been performed (Fig. 21). The direct

tension test results of embedded reinforcement sheets

show that the proposed semi-mechanical model can

describe the behavior after first cracking well

(Fig. 22a). With an increase in displacement, longitu-

dinal splitting defined as delamination (Fig. 21)

occurs leading to a reduced influence of the embedded

boundary conditions of the sheet. Thus, the effects of

the 3.OT locally increases with an increase in

displacement, which leads to a maximum load bearing

capacity equivalent to a non-embedded sheet

(Fig. 22).

It can be concluded that the calculation of the load

bearing capacity of the reinforcement sheet can be

calculated with the proposed semi-mechanical model

without considering the effects caused by the third

order theory, under the assumption that the bond

behavior guarantees the sheet utilization without

longitudinal splitting. Throughout the investigation

of the bond behavior between sheet and concrete, the

longitudinal splitting was prevented by the use of a

tailored SC-FRC [6], which will be shown in a future

publication.

5 Summary and conclusions

In this paper, a novel cementitious composite con-

struction, built from concrete and perforated sheet

reinforcement, is introduced. The novel perforated

reinforcement sheet, to be embedded in concrete, has

potential to be applied in different structural elements,

where the use of conventional reinforced concrete is

either not cost effective or completely in-feasible. The

study described in this paper focuses only on the first

step of the development process, that is the develop-

ment, analysis and optimization of a perforated sheet

for the use as reinforcement. The reinforcement sheet

is thin and is designed to provide sufficient two-

dimensional bond strengths. This has been approached

by punched holes with bulged edges regularly placed

within a perforation system. A semi-mechanical

model, based on the stress distribution of an infinite

sheet with one centered hole, is derived to describe the

load bearing capacity of reinforcement sheets with

various perforation patterns (hole distance and hole

diameter), material behavior and sheet thickness.

The proposed semi-mechanical model was verified

by experimental tension tests of embedded and non-

embedded reinforcement sheets. With this model, a

tool is provided to calculate the load-bearing capacity

of embedded perforated reinforcement sheets with

different geometries and material strengths. This is the

basis for predicting the load bearing capacity of the

proposed composite consisting of fiber-reinforced

concrete and perforated sheet reinforcement.

Acknowledgments This work was financially supported by

the Allianz Industrie Forschung, Germany. The authors also like

to acknowledge the SEAG System-Elemente Aktiengesellschaft

for their support in manufacturing and providing the sheet

reinforcement. Special thanks are sent to Hendrik Fischkandl for

supporting the research project during his diploma thesis. The

opinions expressed in this paper are those of the authors and do

not necessarily reflect the views of the sponsor.

References

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such. Teil 1: Prufverfahren (bei Raumtemperatur), (Metal

materials tension test, part 1: testing method under ambient

temperature)

2. http://www.sofistik.com/. Accessed 2008

3. Mucha S (2003) Development of reinforcement system made

of sheet steel. Leipzig Annual Civil Engineering Report No. 8

165

4. Stowell EZ (1950) Stress and strain concentration at a cir-

cular hole in an infinite plate. National Advisory Committee

For Aeronautics, Technical Note 2073, Langley Aeronautical

Laboratory Langley Air Force Base Va. 15

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(Hybrid composite construction), patent number: DE 10 2007

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German)

6. Wille K (2008) Beschreibung des Tragverhaltens neuartiger

Verbundkonstruktionen unter Verwendung eines flachigen

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composite structures using two-dimensional reinforcing ele-

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978-3-8370-1029-98 (in German)

Materials and Structures