simulation of accordion effect in corrugated steel web with concrete flanges

Computers and Structures 82 (2004) 2061–2069

www.elsevier.com/locate/compstruc

Simulation of accordion effect in corrugated steel webwith concrete flanges

Ling Huang a, Hiroshi Hikosaka a,*, Keizo Komine b

a Department of Civil Engineering, Kyushu University, Fukuoka 812-8581, Japanb Oriental Construction Co. Ltd., Fukuoka 810-0001, Japan

Received 13 December 2002; accepted 26 July 2003

Available online 31 July 2004

Abstract

Prestressed concrete girders with corrugated steel webs are one of the promising concrete–steel hybrid structures ap-

plied to highway bridges. Prestress can be efficiently introduced into the concrete flanges due to the so-called ‘‘accordion

effect’’ of the corrugated web. In this paper, a simple approach is presented to account for three-dimensional pheno-

mena of the accordion effect using link-type elements within a two-dimensional finite element model. The vertical links

are given a very high stiffness to fully transmit vertical shear force, whereas the horizontal link stiffness is given a value

calculated from the out-of-plane bending of a folded plate forming each trapezoidal corrugation. Viability of the ap-

proach is demonstrated through comparison of experimental and numerical results for a large-scale specimen of a pre-

stressed concrete beam with corrugated steel web.

� 2004 Civil-Comp Ltd. and Elsevier Ltd. All rights reserved.

Keywords: Corrugated web; Accordion effect; Composite structure; Prestressed concrete; Finite element analysis

1. Introduction

Prestressed concrete (PC) box girders with corru-

gated steel webs are one of the promising concrete–steel

hybrid structures applied to highway bridges [1–3].

Some advantages of using the corrugated steel web are

summarized as follows:

1. The decreased dead weight of corrugated steel web,

compared to concrete web, leads to reduced seismic

forces and smaller substructures, which will result

in a lower construction cost of the bridge.

2. The corrugated steel webs have a higher shear-buck-

ling strength than flat plate steel webs.

0045-7949/$ - see front matter � 2004 Civil-Comp Ltd. and Elsevier

doi:10.1016/j.compstruc.2003.07.010

* Corresponding author.

3. The corrugated steel webs are more easily fabricated

and constructed than concrete webs.

4. Prestress can be efficiently introduced into the top

and bottom concrete flanges due to the so-called

‘‘accordion effect’’ of corrugated webs.

5. The external post-tensioning is used for PC box gird-

ers with corrugated steel webs, which has many

advantages over internal bonded tendons.

The Maetani Bridge in Japan, completed in 2001

using cast-in-place cantilever construction, is one

application of this concrete–steel hybrid structure.

Its general view is shown in Fig. 1. It consists of a

dual 2-lane bridge of two spans, 75.3+83.3 m, for a

total length of 160 m, with a single-cell box cross-sec-

tion.

Ltd. All rights reserved.

Nomenclature

b, s, t,h the dimensions of a corrugation of a web

plate, as shown in Fig. 2

Ec Young�s modulus of concrete

Es Young�s modulus of steel web

fc0 compressive strength of concrete

G shear modulus of steel web

G0 reduced shear modulus of corrugated steel

web

kM horizontal stiffness of a trapezoidal strip due

to bending, in Fig. 2

kN horizontal stiffness of a trapezoidal strip due

to normal force, in Fig. 2

kh horizontal stiffness of accordion link, as

shown in Fig. 3

kv vertical stiffness of accordion link, as shown

in Fig. 3

t0 equivalent thickness of inclined panel in cor-

rugated steel web

D relative horizontal displacement of a tra-

pezoidal strip, as shown in Fig. 2

s shear stress of corrugated steel web

14500

7500

3460

045

00

1600008330075300

300

Fig. 1. General view of the Maetani Bridge, Japan (dimensions in mm).

2062 L. Huang et al. / Computers and Structures 82 (2004) 2061–2069

For the purpose of enhancing the durability of this

PC bridge, the following construction details have been

adopted to protect the tendons from rust and to ensure

effective inspection and maintenance:

� The bridge box girders are longitudinally post-ten-

sioned using external tendons covered with transpar-

ent sheaths, so that the completeness of cement

grouting can easily be inspected and maintained.

� Web concreting and shear reinforcing become unnec-

essary by use of the corrugated steel webs whose

depth ranges from 6 m above the piers to 2 m at

the abutments.

� The top and bottom concrete flanges are transver-

sally post-tensioned using internal pre-grouted ten-

dons, which are composed of prestressing steels

coated with a cold setting epoxy resin covered with

corrugated polyethylene sheaths.

� To resist the horizontal shear at the interface between

the steel section and the concrete flanges, steel angles

with attached U-shaped steel bars are welded to the

upper and lower steel flanges.

One of the structural characteristics of the corrugated

steel web is its accordion effect, which is a rather compli-

cated three-dimensional (3-D) phenomenon including

both its in-plane and out-of-plane deformations.

Although the structural system is therefore classified as

a 3-D shell structure, it is not appropriate, from the

practical point of view, to analyze the entire structure

according to elastic shell theory. The PC single-cell

box girder should be designed as a beam through the

use of a simplified model that satisfies equilibrium and

suitably chosen compatibility conditions. In this paper

a simple approach is presented to account for the 3-D

accordion effect within a two-dimensional finite element

analysis, with attention towards design of the new type

of concrete–steel hybrid bridges. 2-D link-type elements

are used to model the accordion effect of the corrugated

steel web. In the horizontal direction, the link stiffness is

given a value calculated from the out-of-plane bending

of each trapezoidal corrugation. In the vertical direction,

however, links are given a very high stiffness to fully

transmit vertical shear force. Viability of the approach

is demonstrated through comparison of experimental

L. Huang et al. / Computers and Structures 82 (2004) 2061–2069 2063

and numerical results for a large scale specimen of a pre-

stressed concrete beam with corrugated steel web.

2. Accordion effect and shear deformation of corrugated

steel web

2.1. Formulation of accordion effect

The ‘‘accordion effect’’ of corrugated steel web results

from its low axial rigidity in stretching and contracting.

Let us examine a trapezoidal portion of the corrugated

web cut out at the centre of two inclined plates, as

shown in Fig. 2(a). When the elastic trapezoidal strip

of a unit depth is subjected to two opposite forces P at

its ends A and B (Fig. 2(b)), the relative displacement,

D, between A and B in the direction of P is formulated

using Castigliano�s theorem:

D ¼Z B

A

N oN=oPEsA

þM oM=oPEsI

� �ds ð1Þ

where N and M are axial force and bending moment as

caused by P, respectively, A= t and I= t3/12 are the

cross-sectional area and moment of inertia of the strip

with a thickness t, respectively, and Es is the Young�smodulus of steel web. The relative displacement can

now be obtained from Eq. (1):

D ¼ 1

kNþ 1

kM

� �P ð2Þ

where

kN ¼ Estbþ 2s cos2 h

ð3Þ

kM ¼ Est3

12s2 bþ 2s3

� �sin2 h

ð4Þ

θA B

t

(a) Typical section of corrugated steel web

(b) Deformation of a trapezoidal web

(c) Equivalent bar-spring model

b

b

s

s

s

s

PA B

Ps

=

P PkM

A Bt

b

t t't'

scosθ

cosθ

∆

scosθ

Fig. 2. Simplified model of corrugated steel web.

P/kN indicates the relative displacement due to axial

force and P/kM is that due to bending. The relative dis-

placement D in Eq. (2) is exactly obtained from a 1-D

bar-spring model as illustrated in Fig. 2(c), in which in-

clined legs of the original trapezoid are replaced by hor-

izontal strips with a reduced length scosh as well as an

equivalent thickness t0= t/cosh and a spring of stiffness

kM is inserted in series. It is noted that the sectional area

of the replaced horizontal strip, t0scosh= ts, is equal to

that of the original inclined panel.

2.2. 2-D accordion link element

The 1-D bar-spring model in Fig. 2(c) is now ex-

tended to a 2-D analysis model to account for the 3-D

accordion effect of corrugated steel web. In this 2-D

model, each inclined plate of the corrugated web is cut

vertically along its centre line and is replaced by two

horizontal plates with a reduced length and an equiva-

lent thickness as given in Fig. 2(c). 2-D zero-size link ele-

ments (Fig. 3) are then inserted connecting the nodes of

two separated steel elements, except at the upper and

lower ends of the web where it is welded to steel flanges.

The vertical spring of each link element is given a very

large stiffness kv to prevent relative vertical motion be-

tween the link nodes i and j, transmitting vertical shear

force Q; the stiffness kh of the horizontal spring is given

the value kM multiplied by a vertical mesh size. Thus the

accordion effect developed continuously in the corru-

gated steel web is lumped into the horizontal link

springs.

2.3. Reduced shear stiffness

Yamaguchi et al. [4] tested a series of corrugated steel

webs with either steel or concrete flanges. They reported

the development of almost uniform shear stress-field in

both the longitudinal and inclined panels of the corru-

gated web subjected to bending moment and vertical

shear force.

Provided that a uniform shear stress s is developed

on both the longitudinal and inclined panels of a thick-

ness t in Fig. 2(b), the strain energy density of the in-

clined panel is given by U=s2/2G in which G is the

shear modulus of steel in the web. Since the inclined

Q

kv

kh

Pi

j

Fig. 3. Accordion link element.


panel is modified to a longitudinal panel of an equiva-

lent thickness t0= t/cosh in the proposed model (Fig.

2(c)), however, its calculated shear stress is apparently

reduced to scosh and its strain energy density becomes

U0=(scosh)2/2G0. A modified shear modulus, G0, must

be introduced in order to obtain an equal strain energy

density U0=U which leads to an equal vertical shear dis-

placement between the original corrugated web and the

proposed 2-D model. With this definition, we find the re-

duced shear modulus of G0=Gcos2h for the modified

panel with an equivalent thickness t0.

Fig. 5. FEM mesh of the specimen (dimensions in mm).

3. Test specimen and finite element modelling

The dimensions and boundary conditions of the

large-scale specimen analysed are given in Fig. 4. This

example is taken from a prestressed concrete beam

which was tested by Ata et al. [5]. Since the main pur-

pose of the test program was to compare the fatigue per-

formance of four different steel web joints located at

positions J1–J4 in Fig. 4, the static loading tests were

conducted only within an elastic range of the beam in

advance of the fatigue test. The corrugated web in this

specimen is made of steel plate (Young�s modulus

Es=206 GPa) with a thickness of 9 mm and has almost

the same profiles and dimensions (b=2s=430 mm,

h=30�) as those in the Maetani Bridge already shown

in Fig. 1. The upper and lower steel flanges of 320·16mm are welded to the corrugated web. However, the

steel flanges are cut at four locations J1–J4 to promote

the accordion effect of corrugated web. Material param-

eters reported on the beam examined here include: con-

crete compressive strength fc0=37.9 MPa and Young�s

modulus Ec=23.8 GPa, at the age of 10 days when

tested. The 2-D finite element idealization of the test

specimen and boundary conditions is shown in Fig. 5.

Three types of elements are used: (1) plane stress ele-

ments represent both the concrete continuum and the

steel web, (2) 1-D truss elements represent the steel

3415 6400

13230

P1270

270

2572

4303200

J11385

J2

1000

Fig. 4. Test specimen [5] (

flanges welded to the corrugated web and the reinforcing

bars in the concrete flanges, and (3) link elements model

the accordion effect of the corrugated web. Nine rows of

the accordion link elements are inserted at the intersec-

tions of the horizontal FE mesh with the centre line of

each inclined panel over the corrugated steel web, as

indicated by solid circular symbols in Fig. 5. The hori-

zontal spring of each link element is given a stiffness of

kh=360 N/mm from the value of kM=1.80 N/mm2

(Eq. (4)) multiplied by the vertical mesh size of 200

mm. Perfect bond is assumed at the interface between

the steel and concrete flanges. The beam is simply sup-

ported and is subjected to two concentrated loads, P1

and P2, on each quarter span.

3415

P2

3200 4303200

J3 J4

1385

dimensions in mm).


4. Strains introduced by prestressing force

Four prestressing tendons (diameter 21.8 mm) are lo-

cated in the top and bottom concrete flanges of the spec-

imen, respectively, and the stress of 1300 MPa was

introduced in each tendon. In Fig. 6 the distribution of

normal strain across cross-section at midspan, obtained

by the proposed 2-D modelling, is compared with the

measured values reported by Ata et al. [5]. The numeri-

cal result shows close agreement with the experimental

values and, away from the upper and lower steel flanges,

normal strain decreases rapidly to zero over the central

portion of the web. Although it indicates the apparent

accordion effect of corrugated steel web, the concentra-

tion of normal strains in the web local to the upper

and lower steel flanges is witnessed in both the test

and the analysis.

Fig. 7 gives plots of relative horizontal displacement

between two nodes in each accordion link element posi-

tioned over the corrugated steel web. The accordion ef-

fect of corrugated web under prestressing is not uniform

along the span because the steel flanges are longitudi-

-150

-100

-50

0

50

100

150

-250 -200 -150 -100 -50 0 50

Shear strain (x10-6)

Bea

m d

epth

(cm

)

FEM

Experiment

(k h =360N/mm)steel web

concrete flange

concrete flange

Fig. 6. Distribution of axial strain by prestressing.

row 9row 5row 1

Position of accordion links

Rel

ativ

e ho

rizo

ntal

dis

plac

emen

t (m

m)

-1.8

-1.6

-1.4

-1.2

-1

-0.8

-0.6

-0.4

-0.2

0

row 5row 4row 3row 2row 1

J1 J2 J3 J4

Fig. 7. Accordion movement of the corrugated steel web due to

prestressing.

nally discontinuous at four locations J1–J4. Although

the corrugated steel webs are practically assumed to at-

tract no prestress, the information on the prestress loss

provided by the simple 2-D modelling will be useful in

the initial stages of the design process.

5. Prestressed concrete beam analyses

5.1. Cross-sectional distribution of axial and shear strains

In Figs. 8 and 9, the experimental distributions of

both axial and shear strains across the midspan cross-

section are compared with those from analysis models

(with kh=360 N/mm) under two different loading condi-

tions, namely: (1) a single concentrated load of P1=100

kN, and (2) two symmetrical loads of P1=P2=50 kN. It

is noted that the magnitude of bending moment at mid-

span is equal in both loading cases. The numerical axial

strain distributions for the beams with flat web

ðkh ¼ 1Þ, in which the accordion effect does not occur

at all, are also given for comparison. The distribution

of axial strains indicates strong nonlinearity over the

web depth due to the accordion effect of corrugated

web, whereas the strain is almost linearly distributed in

the flat web. The axial and shear strains in the corru-

gated web show good agreement between the numerical

-150

-100

-50

0

50

100

150

-15 -10 -5 0 5 10 15Axial strain (x10-6)

Bea

m d

epth

(cm

) FEM

Experiment

FEM

(k h =360N/mm)

(k h =δ)

concrete flange

concrete flange

steel web

-150

-100

-50

0

50

100

150

-5 0 5 10 15 20Shear strain (x10-6)

Bea

m d

epth

(cm

)

FEM

Experiment

(k h =360N/mm)

concrete flange

concrete flange

ig. 8. Axial and shear strains over the mid-span section

P1=100 kN).

F

(

-150

-100

-50

0

50

100

150

-15 -10 -5 0 5 10 15Axial strain (x10-6)

Bea

m d

epth

(cm

) FEM

Experiment

FEM

(k h =360N/mm)

(k h =δ)

concrete flange

concrete flange

steel web

-150

-100

-50

0

50

100

150

-15 -10 -5 0 5 10 15Shear strain (x10-6)

Bea

m d

epth

(cm

)

FEM

Experiment

(k h =360N/mm)

concrete flange

concrete flange

Fig. 9. Axial and shear strains over the mid-span section

(P1=P2=50 kN). row 9row 5row 1

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1



Exp

ansi

on a

nd c

ontr

actio

n (m

m)

J1 J2 J3 J4

Fig. 11. Accordion expansion and contraction of the corru-

gated steel web.


and experimental results, and the predictive capability of

the proposed 2-D modelling is satisfactory considering

its simplicity.

The axial strain distributions in the vicinity of a con-

centrated load are extremely different from those at mid-

span shown in Figs. 8 and 9. For the single concentrated

load of P1=100 kN, the numerically predicted strain dis-

tributions beneath the load (section 18) and on the adja-

cent longitudinal panel (section 22), respectively, are

plotted in Fig. 10. Underneath the concentrated load,

a positive local bending occurs in the top concrete flange

developing tensile strain at its lower surface. Although

P1

18 22

-150

-100

-50

0

50

100

150

-40 -30 -20 -10 0 10 20Axial strain (x10-6)

Bea

m d

epth

(cm

)

section 18

section 22

steel web

concrete flange

concrete flange

Fig. 10. Axial strains over sections 18 and 22 due to P1.

the local bending moment influences only a small por-

tion of the concrete flange, some stiffening measures

for the corrugated steel web, such as cross-frames or dia-

phragms, should be provided at cross-sections acted on

by a concentrated force.

5.2. Accordion effect in the corrugated steel web

Nine rows of accordion link elements are positioned

along the horizontal FE mesh over the corrugated steel

web as shown in Fig. 5. For the two loading conditions

either (1) a single load of P1=100 kN, or (2) two sym-

metrical loads of P1=P2=50 kN, the relative horizontal

displacements in accordion link elements along odd

rows are plotted in Figs. 11 and 12, respectively. The re-

sults show that the accordion effect of a corrugated steel

web is dominant in the vicinity of a concentrated load

and, away from that region towards the beam end, the

magnitude of relative displacement in each accordion

link is almost proportional to both the bending moment

and the distance from the centroidal axis of the beam.

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1


row 9row 5row 1


Exp

ansi

on a

nd c

ontr

actio

n (m

m)

J1 J2 J3 J4

P1 P2


gated steel web.

-150

-100

-50

0

50

100

150

0.00 0.02 0.04 0.06 0.08 0.10

Axial displacements (mm)

Bea

m d

epth

(cm

)

section 18

section 22

section 26

section 34

concrete flange

concrete flange

P1

18 22

Fig. 13. Axial displacements of the sections.

0.00

0.05

0.10

0.15

0.20

0.25

0.30

Beam theory

FEM

FEM

Experiment

(k h =360N/mm)

(k h =∞)

Def

lect

ion

(mm

)

Span=12.8m

Fig. 14. Deflection curve due to P1.

0.00

0.05

0.10

0.15

0.20

0.25

0.30

Beam theory

FEM

FEM

Experiment

(k h =360N/mm)

(k h =∞)

Def

lect

ion

(mm

)

Span=12.8m

Fig. 15. Deflection curve due to symmetrical loads of P1=P2.


Nearby a loading point, however, we see that the accor-

dion effect along the centroidal axis (row 5) is dominant

resulting in a positive relative displacement of links (i.e.

stretching of the corrugation) underneath the concen-

trated load and a negative (i.e. contracting) displace-

ment in the adjacent corrugation.

Fig. 13 gives, under a single load of P1=100 kN,

axial displacement distributions across four different sec-

tions in the beam, namely: section 18 beneath the con-

centrated load, sections 22 and 26 on the centre line of

two adjacent trapezoidal corrugations, and section 34

at midspan. While section 18 is predicted to remain al-

most planar during deformation, we note that the adja-

cent plane section 22 exhibits strong nonlinearity in axial

displacement corresponding to both the axial strain dis-

tribution in Fig. 10 and the accordion effect in Fig. 11.

Even away from the concentrated load, the concrete–

steel composite sections 26 and 34 do not still remain

plane due to shear deformation of the steel web.

5.3. Influence of shear deformation on deflection curve

It is known, from the beam theory, that the contribu-

tion of shear deformation to the total deflection of a

beam in flexure approximately increases with the magni-

tude of a nondimensional parameter k=EI/GAwL2 in

which EI is flexural rigidity, Aw is web area and L is

the span length. For the usual steel beams and concrete

beams in which both flanges and webs are made of the

same material, the parameter k is small enough for the

shear deformation to be neglected. In the case of PC

box girder with corrugated steel webs, however, the con-

tribution of shear deformation cannot necessarily be ne-

glected because of its large flexural rigidity and rather

small web area.

Figs. 14 and 15 show the vertical deflections meas-

ured on the bottom face of the beam, subjected to either

a single load of P1=100 kN or symmetrical loads of

P1=P2=50 kN, respectively. In each figure, the deflec-

tion curve obtained from the 2-D corrugated web model

(kh=360 N/mm) is compared with curves from the 2-D

flat web model (kh ¼ 1) and from the beam theory, as

well as the experimental values. The beam theory is

based on the idealized two-flange concrete section with

a web of zero area neglecting its shear deformation.

The proposed 2-D corrugated web model is a little bit

stiffer than the test specimen; the deflections at midspan

predicted by the model are about 10% smaller than the

measured values. The difference of deflection between

the FE models either with corrugated web or with flat

web is not so large, indicating that the flexural rigidity

of the beam is not affected very much by the accordion

effect of corrugated steel web. However, an appreciable

error is introduced into the deflection by the elementary

beam theory which neglects the shear deformation of

steel web. Rather high depth/span ratio (h/L=1/6.4)

of the beam specimen also amplifies the contribution

of shear deformations.

5.4. Accordion effect locally prevented by web stiffener

As described in Sections 5.1 and 5.2, the accordion

effect of a corrugated steel web is dominant in the narrow

region close to a concentrated load causing also local

bending in the concrete flange. The situation that the con-

crete flanges are subjected to external concentrated forces


is also possible at either intermediate supports of PC gird-

ers or at cable anchorages of cable-stayed PC bridges, and

therefore appropriate stiffening measures for corrugated

steel web should be provided. Let us suppose that a

cross-frame or a diaphragm, attached to a longitudinal

panel of corrugated web, is provided at the cross-section

acted on by a concentrated load of P1=100 kN. In the

proposed 2-D FE analysis, the effect of the cross-frame

or diaphragm is modelled by giving sufficiently high

Young�s modulus to only the stiffened longitudinal panel.

Fig. 16 gives plots of the relative horizontal displace-

ments in the accordion link elements after the web stiff-

ening, corresponding to Fig. 11 which gives the same

quantities without the web stiffener. The comparison

of Fig. 16 with Fig. 11 demonstrates that the supposed

web stiffening is highly effective for restricting the local

accordion effect of a corrugated web nearby a concen-

trated load, with nearly zero relative horizontal displace-

ments in link elements along the centroidal axis. Fig. 17

compares the numerically predicted axial strain distribu-

tions beneath the load (section 18) and on the adjacent

longitudinal panel (section 22) before and after web stiff-

ening, respectively. We see that the web stiffening effec-

row 9row 5row 1


Exp

ansi

on a

nd c

ontr

actio

n (m

m)

J1 J2 J3 J4

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1


P1


gated steel web with web stiffener under the concentrated load.

-150

-100

-50

0

50

100

150

-40 -30 -20 -10 0 10 20 30Axial strain (x10-6)

Bea

m d

epth

(cm

)

section 18 (with stiffener)

section 18 (without stiffener)

section 22 (without stiffener)

section 22 (with stiffener)

concrete flange

concrete flange

P1

18 22

Fig. 17. Axial strains over sections 18 and 22 due to P1.

tively reduces the positive local bending of the top

concrete flange underneath the concentrated load.

6. Concluding remarks

A simple 2-D finite element approach has been pro-

posed to account for the 3-D accordion effect of the cor-

rugated steel web used in hybrid PC bridges. The 3-D

corrugated web is modelled by a 2-D flat web with par-

tially modified thickness, and 2-D nodal link elements

are used for representing the accordion effect.

To illustrate the effectiveness of the proposed

method, analyses of a large-scale PC beam specimen un-

der either prestressing force or vertical loadings were

presented. The main purpose of the analyses was to as-

sess the performance of the 2-D models for 3-D accor-

dion effect in a corrugated steel web within the elastic

range, as well as to predict some structural characteris-

tics of PC beams with corrugated steel webs. The inelas-

tic behaviour of the specimen was not pursued in either

the test or the analysis. Some conclusions are made con-

cerning the 2-D modelling used in this research and its

application to hybrid PC beams.

1. The proposed 2-D modelling was successful in repre-

senting the 3-D accordion effect of corrugated steel

webs on the deflection curve, strains introduced by

prestressing, and the strain distribution under vertical

loadings.

2. The use of corrugated steel webs has a strong effect

on the distribution of axial strain over the web due

to its accordion effect. That is, the axial strain de-

creases rapidly to zero over the central portion of

the web, although the concentration of strain in the

web local to the upper and lower flanges is witnessed

in both the test and the analysis.

3. Flexural rigidity of the hybrid PC beam is not af-

fected very much by the accordion effect of the corru-

gated steel web. However, an appreciable error is

introduced into its deflection calculated by elemen-

tary beam theory neglecting the shear deformation

of steel web, due to the large flexural rigidity and

rather small web area of the hybrid PC beam.

4. The web stiffening provided by a cross-frame or a

diaphragm is highly effective for restricting the local

accordion effect of the corrugated web nearby a con-

centrated load.

Acknowledgment

The authors would like to acknowledge Mr. Y. Ata

of the Oriental Construction Co., Ltd., Japan, for his


important contribution to this work. Special thanks are

due to Prof. John Bolander Jr. of the University of Cal-

ifornia, Davis, USA, for his encouragement and invalu-

able suggestions for improving the paper.

References

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simulation of accordion effect in corrugated steel web with concrete flanges

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