BSE Public CPD Lecture – Textile-Cement Composites from baskets to sustainable homes and jet engines on 24 November 2009 Organized by the Department of Building Services Engineering, a public CPD lecture delivered by Professor Barzin Mobasher on Textile-Cement Composites from baskets to sustainable homes and jet engines was held on 24 November 2009 (Tuesday).

Power Point file of the CPD lecture – Part I

Power Point file of the CPD lecture – Part II Professor Barzin Mobasher is Professor of Structural Materials at the Department of Civil and Environmental Engineering at Arizona State University. He has more than twenty five years of research experience in construction materials and experimental mechanics, and has published more than 100 papers in various journals and conference publications. He obtained his Ph.D. in 1990 from Northwestern University and joined Arizona State in 1991. His research interests include modeling the mechanical properties of cement based composite materials, structural testing, experimental mechanics, and durability of construction materials. He is a member of American Ceramics Society, American Concrete Institute, and American Society of Civil Engineers.

Souvenir presentation to Professor Barzin Mobasher by Professor W.K. Chow

Textiles are among the first products of human engineering endeavor and have been used for at least the past 8000 years. We have used textiles for clothing, storage, shelter, transportation, and composite materials, and are still dependant on them for many new and innovative functions. As we continuously struggle to develop more sustainable systems and control available resources, economical considerations for use of construction materials becomes of paramount importance. Concrete materials global production and use has surpassed the 6 billion tons per year mark, a consumption rate that is not sustainable in consideration to green house gas generation due to cement production. In this lecture, Professor Mobasher presented an overview of the recent developments in cement based textile composites as sustainable materials for construction industry.

The lecture concluded with an overview of recent experimental and modeling work in the application of textile materials to Jet engine containment systems.

CPD public lecture by Professor Mobasher

23-Dec-09

1

Textile-Cement Composites:From jugs and baskets to sustainable homes and jet

engines

Barzin Mobasher, PhD, PEDepartment of Civil and Environmental Engineering

Arizona State University

Invited Talk, Hong Kong Polytechnic University, Nov. 23, 2009

Temporal, Spatial, and Scientific Span of Cement & Concrete Technology

DisciplinesMaterials ScienceEngineeringChemistryMechanics Computational TechniquesManufacturing products and systemsSustainable developmentTechnical & non-technical labor pool

Space

Time

Seconds to Centuries

1 to 3x1010 Seconds

hydration Early age Long termPerformance

Service life

nanometers to kilometers

1x10-9 to 1x103 meters

Sustainability: Concrete Consumption in US Concrete Specified vs. Delivered

6000

8000

10000

engt

h, p

si

All concrete classes28 day strength

Each data point = 100 cubic yardsOver-strength

Level

2000 4000 6000Specified f'c, psi

2000

4000

6000

Del

iver

ed S

tre

Source: ADOT Database for One ready mix supplier over a course of two years

Our Generation’s Challenge

The need for a safe and secure shelter is an inherent global problem.

Approximately 924 million people worldwide, (31.6 percent of the global urban population) lived in slums in 2001 [UN-Habitat]Habitat].

This figure will double to almost 2 billion In the next thirty years, unless substantial policy changes are put in place.

Historical Perspectives

Throughout centuries technology has supported human development

Water – Collection, transportation, storage

– liquids, oils q ,– Jugs and Ceramic materials,

Food– agricultural products, food storage, transportation– Baskets, Textiles, woven fabrics

Shelter– Construction, building materials , cements

23-Dec-09

2

Woven Fabrics are among the first engineered materials

A funerary model of a weaver's workshop found in an Egyptian tomb. This model contains a horizontal loom, warping devices and other tools, and weavers in action.

History of weaving

•20K – 30K BC First string by twisting of plant fibers. •7000-8000 BC Cloth making in Mesopotamia and in Turkey. •1766-1122 BC Shang Period in China- treadle and frame loom system•700-1000 Cotton fiber to Anasazi land via trade routes to Mesoamerica. •11th century Invention of weaving patterns used today•1760-1815 Industrial Revolution, Mechanization of cloth weaving

Pottery, Ceramics, cements

10,000 BC - 6,000 BC The earliest known pot making in parts of Asia and middle east. 9,000 BC The first use of functional pottery vessels. 8,000 BC Ancient glass manufacture flourished in Upper Egypt 2,350 BC Ancient Egyptian pottery Fourth, Fifth, and Sixth Dynasties, 1,500 BC Glass was produced independently of ceramics.

Ben Sham Culture China: 2 00 C

Greek Hydra: 533 B.C. Earthenware with slip decoration2500 B.C. Earthenware

with slip decoration.

Earthenware with slip decoration. Courtesy of IMA Pantheon, Rome

Bam Citadel, 2500 year old archeological site in Iran, Dec 2003

23-Dec-09

3

Long Beach, Mississippi- Reinforced Concrete House

Hurricane Katrina, August, 2005

Long Beach, Mississippi, October 30, 2005 -- A lone, mitigated home stands alone in Hurricane Katrina FEMA/Mark Wolfe

Construction systems based on empirical approaches – Hurricane Katrina

Natural disasters are a "growth" industry

•Since the 1960s, economic losses from natural disasters on a global scale have tripled.

•In the same period insured losses have quintupledlosses have quintupled.

•Berz, 1992, Natural Hazards, 5, 95-102

23-Dec-09

4

Population GrowthRethink Engineering of Construction Materials : Focus on Fundamentals of Mechanics, Materials Science

Structure

Performance

Mechanical properties,fracture and FEM modeling onToughening Mechanisms

Full scale testsOptimizationCode development Long term PerformanceDurability

Processing & ManufacturingProperty

Composites processing Lab,extrusion, pultrusion, computer assistedmanufacturing.

materials characterization,SEM facility, XRD, Interfaces and matrix modifications. New fibers& composites.

Toughening Mechanisms

Multi-scale and multi-discipline Approach: Cradle-Grave-Cradle

Sustainable Materials- Sustainable Design Guides

Strengthening approaches

Fabric Reinforced Cement Composites

Sandwich composites

Experimental Characterization Experimental Characterization

Theoretical Modeling

Design Guides

Repair and Retrofit

Toughening Due to Interlock Mechanisms

Mechanisms:– Debonding and pullout, bridging, closing pressure,

crack face stiffness, stress intensity reduction. Three Main interdependent Variables: Bridging Stress, Crack length, Crack opening profile

Variables: Stress crack-width relationship *(u) Stress distribution along crack length Crack opening (width) profile

c

0

af

I

a

K = *(u) g(1, ) da

0 f

a aIF

f IP

a a

2 KCOD = *(u) K d d

E' F

*(x)u(x)

PP FRC Composites Carbon Fiber Composites

R + n Rm 1

R + Rm n2

Rm

Toughness Enhancements in Brittle Matrix Composites: R-Curves

Green’s function Approach:

G(a,x) = green’s functiona = crack lengthlb = bridging zone length

0

bl

b b bK ( l ) G( a,x ) ( x )dx

R + Rm n2

R + Rm n2

Rm

R

R + n Rm 1

R + Rm n2

a

Potential Energy Approach:

u(x) = crack opening profile

lb bridging zone lengthb = bridging stress

0

2bl

b b

duR ( u ) dx

dx

Pullout Modeling of Fabrics

1

Crack DeflectionCrack Deflection

2

Yarn Debonding

23-Dec-09

5

FEM Simulation: Coupled problem of matrix and interface crack growth

Fiber Pullout

Closing Pressure Formulation

Toughening of Matrix

Ph

Pv

Mobasher, B., and, Li, C. Y., "Modeling of Stiffness Degradation of the Interfacial Zone During Fiber Debonding," Journal of Composites Engineering, Vol. 5, N0. 10-11, pp. 1349-1365, 1995.

fiberSliding contact

Interface

Substrate

Matrix Toughening model-FEM

due to applied load

60

80

100

-mm

1/2

due to fibers

composite

19 21 23 25Crack Length, mm

0

20

40

60

KI, M

Pa-

FEMR-Curve Model

P

Mobasher, B., and, Li, C. Y., "Effect of Interfacial Properties on the Crack Propagation in Cementitious Composites," Journal of Advanced Cement Based Materials, Vol. 4. No. 3, Nov. Dec. 1996, pp. 93-106.

Pultruded Cement composites

Tensile Strength = 50 MPa, strain Capacity = 1%

30

40

50

MPa

Unidirectional

0/90/0

0.000 0.004 0.008 0.012 0.016Strain, mm/mm

0

10

20Stre

ss,

Mortar

GFRC

Fabrics in Paste

Polyethylene (PE) Woven Fabric

E=2 GPa

AR GlassBonded Fabric

E= 78 GPa

Polypropylene (PP)Knitted Fabric

E=6 GPa

Slurry Infiltrated Fabric Pultrusion based approaches

Mobasher, B., and Pivacek, A.,”A Filament Winding Technique for Manufacturing Cement Based Cross-Ply Laminates,” Journal of Cement and ConcreteComposites,20 (1998) 405-415.

23-Dec-09

6

New composites with fabrics

Multi Layer

Sandwich layers

Tension, Compression,and beam members

High pressure pipes

Effect of Processing- Fabrics vs. Conventional GFRC

12

16

20

MPa

AR Glass Fabric

GFRC Vf =5%

E-GlassFabric

0 0.01 0.02 0.03 0.04Strain, mm/mm

0

4

8Stre

ss,

PE Fabric

Mortar

ECC

Various stages of cracking Crack Spacing measurement

Damage evolution measurement using image analysis. Crack spacing and

15

20

25

MP

a60

80

cing

, mm

BT-GNSP21

Crack spacing and the stress-strain response of AR Glass fiber composites

0 0.01 0.02 0.03 0.04Strain, mm/mm

0

5

10Str

ess,

0

20

40

Cra

ck S

pac

Homogenization of Crack spacing

0.6

0.8

1

utio

n Fu

ncti

on

Zone 1= 0 015

Zone 2.0273

Zone 3 = 0.0387

15

20

25

MP

a

Zone 3

Zone 2

Zone 1

0 10 20 30 40Crack Spacing, mm

0

0.2

0.4

Cum

ulat

ive

Dis

trib = 0.015

AR-Glass Fabric

0 0.02 0.04 0.06Strain, mm/mm

0

5

10Str

ess,

Zone 1

AR-Glass Fabric

Tensile ResponseGlass

12

16

20

ess,

MP

a

12

16

20

ess,

MP

a

PultrudedCast

0 0.02 0.04 0.06 0.08Strain, mm/mm

0

4

8

Ten

sile

Str

e

0 0.02 0.04 0.06 0.08Strain, mm/mm

0

4

8

12

Ten

sile

Str

e

23-Dec-09

7

Crack SpacingEffect of Processing

12

16

20

s, M

Pa

40

60

acin

g, m

m

Stress-StrainCrack Spacing

12

16

20

, MPa

40

60

acin

g, m

m

Stress-StrainCrack Spacing

0 0.02 0.04 0.06Strain, mm/mm

0

4

8Stre

ss

0

20

Cra

ck S

pa

p g

Pultrusion

0 0.02 0.04 0.06Strain, mm/mm

0

4

8Stre

ss,

0

20

Cra

ck s

pa

Cast

Stiffness degradation & Crack Spacing

100

1000

ffne

ss, M

Pa

Glass Fabrics

80 60 40 20 0Crack Spacing, mm

1

10

Tan

gent

Stif

Polyethylene Fabric

Mobasher B, Peled A, Pahilajani J. Distributed cracking and stiffness degradation in fabric-cement composites. Materials and Structures 2006; 39(287):317–331.

CastPultrudedPP

SEM observations

Reinforcing direction

non-coated yarns

Load Transfer Mechanism Attributed to the Failure of Junctions

Failure of Junctions High efficiency factor obtained by anchorage of polymeric & fracture of brittle fibers

23-Dec-09

8

Anchorage due to interlock Effects of Matrix formulation on the pullout response

40

60

d (l

bf)

ControlWith Flyash

AR-glass + Pultrusion Process

0 0.1 0.2 0.3 0.4 0.5Deformation (inch)

0

20

Loa

d

Open net mesh allows penetration between the fabric openings and results in mechanical anchoring

Enable to control: orientation, distribution and volume content of the reinforcement

Different geometries of fabrics - wide variety of properties

Easy to handle and place in precast products

Cheap polymeric fabrics, PP, PVA, PE

Anchorage of polymeric based fabrics is the primary advantage for fabrics as reinforcement

Bonded Fabrics- Alkali Resistant Glass

500 m

Flexural Response of Cement Composites

300

400

500

N

0 0.4 0.8 1.2Displacement, in

80

lbs

0 10 20 30Displacement, mm

0

100

200Loa

d,

0

40

Loa

d, l

Actuator DisplacementLVDT Displacement

Aldea C. M., Mobasher, B., Jain, N., “Cement-Based Matrix-Grid System For Masonry Rehabilitation,” Textile Reinforced Concrete (TRC) - German/ International Experience symposium ACI SP-244-9, pp. 141-156, 2007.

23-Dec-09

9

Microstructural Evaluation

Crack DistributionCrack Bridging results insignificant energy dissipation

Composite Laminate Theory for Continuous Fiber/Textile Systems

Unidirectional approach for each layer

or in matrix form:

11

ik

ij

ijk

ik

kijk

ij

S

Sm=n, n

112

2

1

12

2

1

1

66

2221

1211

12

2

1

00

0

0

iii

k

S

SS

SS

)()()()( GSESESES

12

662

221

1212

111

111

m=1, 1

hmhm-1

Mobasher, B., Pivacek A., and Haupt, G. J. ” Cement Based Cross-Ply Laminates,” Journal of Advanced Cement Based Materials, 1997, 6, pp. 144-152.

Response of a 6 stack 0/90/0 lamina

8

-6

-4

-2

0

2

4

6

8

10Strain Distribution

z,m

m

50

100

150

Nom

inal

Str

ess,

MP

a

0 0.5 1 1.5 2 2.5 3 3.5

x 10-3

-10

-8

mm/mm

0 2 4 6 8 10 12-10

-8

-6

-4

-2

0

2

4

6

8

10Stress Distribution

x

MPa

z,m

m

0 0.5 1 1.5 2 2.5 3 3.5 4-10

-8

-6

-4

-2

0

2

4

6

8

10

Transverse Stress

MPa

z,m

m

0 0.5 1 1.5 2 2.5 3 3.5

x 10-3

0

Comparison With Experimental Results of unidirectional and 0/90/0 composites

40

50

60

Stress

Unidirectional

Theory

Experiment

t1

= 10 MPa

t2

= 5 MPa

c1

= 40 MPa

c2

= 40 MPa

12

= 5 MPa

23

= 5 MPa

0.000 0.005 0.010Strain, mm/mm

0

10

20

30Stress, MPa

[0/90]s

Experiment

Theory

Em = 30000

Ef = 70000

Vf = 5%

m = 0.18

Comparison of PPFRC with Experiments

ModelSimulation

Experiments,Pivacek, Haupt, and St

ress

, MP

a 15

10

t/2

t/2

k = 1K=4

k = 2

hn

h1

h2

h3

k = 3

k = n-2k = n-1k= n

21

Mid-Plane

hn-2

PositivDirecti

8.0.,5.,0

)(

0

10

umki

Damage Evolution Law0.000 0.005 0.010 0.015Strain, mm/mm

Polypropylene Fiber Composites

Vf = 6% Em= 30000 MPa Ef = 8000 MPam = 0.18 f = 0.25t1= 5 MPa w0= 3.5e-4 Softening Coefficient

Mobasher, 1998S

5hn-1

k n n 2

Modeling of a Single Crack Bridging

23-Dec-09

10

Modeling of Fabric Pullout

Loa

d, N

AR Glass, Expt.AR Glass, Simul.PE, Expt.PE, Simul.

50

100

150

200

ad, N

Expt. Math. YarnMath. Woven

100

150

200

Slip, mm

00 2 4 6 8

P

DebondedLength

U

Anchorage

L

Elastic Foundation, K0

Fill Yarn

Deformation, mm

Loa

0

50

0 0.5 1 1.5 2 2.5

AR Glass Fabric

Modeling of Multiple Cracking

I II III IVCrack Spacing, SDamage,

C

S=S + S e1 0

- ( i- mu)

A

0 Strain

DamageCrack Spacing

mut1

Damage,

Crack Spacing, S

B

C

= + ( - )1 i t1

Modeling of Tensile Response

Stress

BOP

I II IIIIV

B

A

0 Strain

BOPMatrix

CompositeFabric

mut1

mu

t1

C

Modeling of Composite Tensile Response

0

20

40

60

Cra

ck s

paci

ng, m

m

0

1000

2000

3000

4000S

tiff

ness

, MPa CS, Expt.

CS, Simul.Stiffness, Expt. Stiffness, Simul.

0 0.01 0.02 0.03

Strain, mm/mm

0

4

8

12

16

Str

ess,

MP

a

Expt.Simulation

Modeling of Fabric Composites in Tension

10

20

30

40

50

Cra

ck S

paci

ng, m

m

Expt. 40% flyashExpt. Control

0 0.02 0.04 0.06Strain, mm/mm

0

10

20

30

Stre

ss, M

Pa

0 C

Expt. 40% flyashExpt. ControlSimulation 40% FA

Control

Typical Uniaxial Tension Test

23-Dec-09

11

Unified material laws and cracking criteria Finite difference model

One way pullout segment

One way pullout segment

Two way pullout segment

Free body diagram at each node

Middle segment

Left end segment

n1 n2 n4n3

Right end segment

n6

n5

Equilibrium equations at typical nodes

1 2 1 22

1 1 2

10

2 2 2

y y y y

y y

E E E EA k h s A s

1 1 1 12

1 1

20

2 2 2i i ii i i i

y i y i i i y i

y y y y y y y

i

E E E E E E EA s A k h g h s A s

1 1 1 12

1 1

20

2 2 2i i ii i i i

y i y i y i

y y y y y y y

i

E E E E E E EA s A k h s A s

n1

n2

n3

1 1 2

1

10

2 2 2n n n ny y y y

y n y n n

E E E EA s A k h s

1 1 2

1

10

2 2 2n n n ny y y y

y n y n n

E E E EA s A k h s Ph

1 2 1 22

1 1 2

10

2 2 2

y y y y

y y

E E E EA k h s A s Ph

1 12 2 2y i y i y ii

n6

n5

n4 Move to the right -- > driving force

Parametric Study

Bond slip model

1

2

3

4

She

ar S

tres

s (M

Pa)

max=4 MPa

max=3 MPa

max=2 MPa

(a)

Matrix Strength

2.5

5

7.5

10

Spr

ing

For

ce (

N)

SFmax=10 N

SFmax=7.5 N

SFmax=5 N

(d)

0 0.25 0.5 0.75 1 1.25Slip (mm)

0

Yarn stress strain model

Matrix Grade

0

1

2

3

Mat

rix

Str

engt

h (M

Pa)

fcr=2.0 MPa

fcr=2.5 MPa

fcr=3.0 MPa(b)

Spring force slip model

0 0.005 0.01 0.015 0.02 0.025Strain (mm/mm)

0

250

500

750

1000

1250

Str

ess

(MP

a)

slack=0.006

slack=0.004

slack=0.002

slack=0.000

(c)

0 0.25 0.5 0.75 1 1.25Slip (mm)

0

Composite tensile stress strain response

Bond strength

5

10

15

Com

posi

te S

tres

s (M

Pa)

BND_4.0BND_3.0BND 2.0

(a)

Matrix strength

5

10

15

Com

posi

te S

tres

s (M

Pa)

MTX_3.0MTX_2.5MTX 2.0

(b)

0 0.005 0.01 0.015 0.02 0.025Strain (mm/mm)

0

BND_2.0

0 0.005 0.01 0.015 0.02 0.025Strain (mm/mm)

0

MTX_2.0

Slack level

0 0.005 0.01 0.015 0.02 0.025Strain (mm/mm)

0

5

10

15

Com

posi

te S

tres

s (M

Pa)

SLK_0.006SLK_0.004SLK_0.002SLK_0.000

(c)

Strength of spring

0 0.005 0.01 0.015 0.02 0.025Strain (mm/mm)

0

5

10

15

Com

posi

te S

tres

s (M

Pa)

SPR_10.0SPR_7.5SPR_5.0SPR_0.0

(d)

23-Dec-09

12

Nominal stress strain response in matrix

Bond strength

1

2

3

Con

cret

e T

ensi

le S

tres

s (M

Pa)

BND_4.0BND_3.0BND_2.0

(a)

Matrix strength

1

2

3

Con

cret

e T

ensi

le S

tres

s (M

Pa) MTX_3.0

MTX_2.5MTX_2.0

(b)

0 0.005 0.01 0.015 0.02 0.025Strain (mm/mm)

00 0.005 0.01 0.015 0.02 0.025

Strain (mm/mm)

0

Slack level

0 0.005 0.01 0.015 0.02 0.025Strain (mm/mm)

0

1

2

3

Con

cret

e T

ensi

le S

tres

s (M

Pa)

slack=0.006

slack=0.004

slack=0.002

slack=0.000

(c)

Strength of spring

0 0.005 0.01 0.015 0.02 0.025Strain (mm/mm)

0

1

2

3

Con

cret

e T

ensi

le S

tres

s (M

Pa)

SPR_10.0SPR_7.5SPR_5.0SPR_0.0

(d)

Crack spacing – composite strain

Bond strength

25

50

75

100

Ave

rage

Cra

ck S

paci

ng (

mm

) BND_4.0BND_3.0BND_2.0

(a)

Matrix strength

25

50

75

100

Ave

rage

Cra

ck S

paci

ng (

mm

) MTX_3.0MTX_2.5MTX_2.0

(b)

0 0.005 0.01 0.015 0.02 0.025Strain (mm/mm)

0

Strength of spring

0 0.005 0.01 0.015 0.02 0.025Strain (mm/mm)

0

25

50

75

100

Ave

rage

Cra

ck S

paci

ng (

mm

) SPR_10.0SPR_7.5SPR_5.0SPR_0.0

(d)

Slack level

0 0.005 0.01 0.015 0.02 0.025Strain (mm/mm)

0

25

50

75

100

Ave

rage

Cra

ck S

paci

ng (

mm

) slack=0.006

slack=0.004

slack=0.002

slack=0.000

(c)

0 0.005 0.01 0.015 0.02 0.025Strain (mm/mm)

0

Final crack spacing

Use basic model

Deterministic crack 1 run for each Vf

– Mean fcr = 2 MPa

– Stdev = 0.0 MPa16

20

24

28

Spa

cing

(m

m)

Deterministic Crack 1 Sample

Stochastic Crack (5 Samples)

Stochastic crack 5 runs for each Vf

– Mean fcr = 2 MPa

– Stdev = 0.001 MPa

1 2 3 4 5Volume Fraction (%)

4

8

12

16

Fin

al C

rack

S

Simulation of AR-glass fabric tension specimen

Dimension

8x100x500, clear length 300 mm

Yarn

dy = 0.374 mm, Ay= 0.11 mm2

Ey = 76 GPa

tu = 1,300 MPa

Vf = 1.4% (3 layers)

Matrix

Fine mix concrete

fcr = 7 MPa, Ec = 30 GPa

Deterministic Crack, 2501 nodes0 0.1 0.2 0.3

Slip (mm)

0

2

4

6

She

ar S

tres

s (M

Pa)

Bond slip

Stress in matrix and Fiber as a function of applied strain

Stress in matrixStress in Fiber

Tensile and Flexural Responses Do not Correlate Directly

15

20

25

xura

l Str

ess,

MPa

0 0.02 0.04 0.06 0.08 0.1

Tensile Strain, mm/mm

15

20

25

MPa

MOR

0 10 20 30 40 50Flexural Deflection, mm

0

5

10

15

Ela

stic

ally

Equ

ival

ent F

lex

FlexureTension

0

5

10

15

Ten

sile

Str

ess,

LOP

BOP

UTS

23-Dec-09

13

Cumulative tensile and Flexural Strength Distribution

0.6

0.8

1

babi

lity

, p

BOPUTS

0 4 8 12 16Tensile or Flexural Strength, MPa

0

0.2

0.4

Fail

ure

Prob LOP

MOR

Simplified Tensile and Compressive stress strain model

c cy= cr E t

cr=crEE

E

cr =

p crE=

strain-hardening

c cy cr= cu cu cr=

E = Ec

Compression Elastic Plastic model Tension Strain Hardening-Softening model

cr trn cr= tu tu cr=

Et

Soranakom C, Mobasher B. Correlation of tensile and flexural response of strain softening and strain hardening cement composites. J. Cement & Concrete Composites, 2008;30:465-477.

Closed Form Moment-Curvature Formulation

Incrementally impose 0 < t < tu (or 0 < < tu)

Strain Distribution

Stress Distribution

F = 0, determine Neutral axis, k

M = Ciyci+ Tiyti and =c/kd

Normalization M’=M/M0 and ’=/cr

1 10

kd

c cF b f y dy

1 101

kd

c cc

by f y ydy

F

c

0 < t < tu

k

h

C2

T1

T2

T3

C1 M

Moment curvature

Zone 2.1 Tension Hardening-Compression Elastic

1 < < , 0 < <

c cr=

1hc1 kh

1yc1

Fc1

fc1

t cr=

1 ht1h

1yt1

yt2ft1

2 ht2

cr

Ft22

ft2

Ft1

Soranakom C, Mobasher B. Correlation of tensile and flexural response of strain softening and strain hardening cement composites. Cem Concr Compos, 2008;30:465-477.

Zone 3.1 Tension Softening-Compression Elastic

< < tu 0 < <

ctop cr=

1hc1 kd

1yc1

Fc1

fc1

tbot cr=

1 ht1 d 1yt1 yt2ft1

2 ht2

crFt22ft2

Ft1

3 ht3 3 Ft3

yt3

ft3

trn

Soranakom C, Mobasher B. Correlation of tensile and flexural response of strain softening and strain hardening cement composites. Cem Concr Compos, 2008;30:465-477.

Closed Form Solutions for Strain Hardening/Softening material

216

cr

cr cr

M =M' M

M bd E

'2

cr

cr

cr d

23-Dec-09

14

Model for strain Hardening-softening

Range k

1

0 < < 1 1

1 for =1

2

1 for 1

1

k

3 2

1 1 11

1

2 1 3 3 1'

1

k k kM

k

2.1 221 21D D 3 3 2

21 21 21 21 21 21 212 3 3'

C k C k C k CM

2cr cr

1M M M '= bd E M '

6

2 1cr

cr cr

2 = '

k d

1 < <

0 < <

21 2121 2

21

D Dk

D

221 2 1 2 1D

21211

Mk

3 2 2

21 2

(2 3 1) 3 1C

3.1

< < tu

0 < <

231 31

31 231

D Dk

D

231 2 1 2 2 1D

3 3 231 31 31 31 31 31 31

3131

2 3 3'

1

C k C k C k CM

k

3 2 2 2 2

31 2

(2 3 1) 3 3 1C

Range 2.1Compression Elastic - Tension Hardening

2A ( 1 2 )k 2

A

A1

2 1

2 1

kSpecial Case: Ec =Et (=1 ) , Elastic perfectly plastic tension (=0 )

A (

Ak )

)'(M k )'(M A, ( k

A

)

0.5 20.5( 1 - 2 ) 2 - 1 1 60.773 0.108 10 x k 0.507 0.686

0.2 20.2( 1 - 2 ) 2 - 1 2 60.654 0.516 10 x k 1.105 0.383

0.1 20.1( 1 - 2 ) 2 - 1 2 61.276 0.289 10 x k 1.461 .234

0.05 20.05( 1 - 2 ) 2 - 1 2 61.645 .1632 10 x k 1.720 .1401

0.01 20.01( 1 - 2 ) 2 - 1 10.852 0.456 k 1.342 0.371

Range 2.1Compression Elastic - Tension Hardening

Elastic perfectly plastic tension (=0 )Elastic (=1 )

=ratio of Slopes

Range 3.1 Compression Elastic Tension-Softening

Effect of Ultimate Strain Capacity,

=ratio of ultimate strain capacity to first crack strain

Range 3.1 Compression Elastic Tension-Softening

Effect of Post peak Stress level,

Post peak Stress level,

Strain Softening Materials (=0, =1)

Effect of post-peak tensile strength,

0.3

0.4

0.5

xis

dept

h ra

tio, k

= 10

cu = 0.004

tu = 0.0152

3

zed

Mom

ent,

M'

0 35

=0.68

=1.00

M’= 1.910

M’=1 0145

M’=2.727

0 4 8 12 16Normalized top compressive strain,

0

0.1

0.2

Neu

tral

ax

=0.01=0.35

=0.68

=1.00

=0.18

0 20 40 60Normalized Cuvature, '

0

1

Nor

mal

iz

=0.01

=0.35

=0.18

crcr

2 =

d

2cr cr

1M = bd E

6M '( ) = 3

+

M’=1.0145

M’= 0.530

M’=0.03

Soranakom, C., and Mobasher, B., “Closed-Form Solutions for Flexural Response of Fiber-Reinforced Concrete Beams,” Journal of Engineering Mechanics, Vol. 133, No. 8, August 2007, pp. 933-941

23-Dec-09

15

Interaction of Failure Zones Load Deflection Response

Moment area method

Crack localization rules

Moment

Mmax Non-Localized Zone

Localized Zone

P/2

S S S

P/2

Curvature

M0 Mfail j,Mj)

j-1,Mj-1)

Loading Unloading

S S/2

cS

P Localized Zone

Non-Localized Zone

Axis of Symmetry

M

M0

L

0

Tensile Stress-strain and Crack Spacing

Polyethylene (PE) Woven Fabric

E=2 GPa

AR GlassBonded Fabric

E= 78 GPa

Polyethylene Fabric composites

Alkali Resistant Glass Fabric Repair of Unreinforced Masonry Walls

MD

XMD

23-Dec-09

16

In-plane shear tests to simulate seismic action.

Full coverage, on one side of the wall only.

Three walls tested varying the reinforcement layout:

Wall 1 – 2 plies 0-90

Wall 2 – 2 plies 0-90, +/-45

Wall 3 – 3 plies 0-90, 2 x +/-45

Wall Retrofit: Fabric Cement, USACOE-CERL

300

-10 0 10 20 30Displacement, mm

-300

-200

-100

0

100

200

Cyc

lic

Hor

izon

tal L

oad,

kN

Load-Displ loops(-) Negative backbone(+) Positive backbone

2 Plies, 0/90°

The Beam-Column Joint Retrofit

0 20 40 60 80 100Time, sec

-60

-40

-20

0

20

40

60

Bea

m ti

p di

spla

cem

ent,

mm

-60 -40 -20 0 20 40 60Beam tip displacement, mm

-30

-20

-10

0

10

20

30

Bea

m C

ycli

c L

oad,

kN

CFRP 1 layer(L) loopsEnvelope of CFRP1

Beam Displacement-Cyclic Load

Drop Weight Impact

Hammer SpecimenLever arm LVDT

Impact response of 6 layer glass fabric composite

Impact response of 6 layer glass fabric composite Impact Event Characteristics

2000

2500

3000

orce

, N

20

30

40

eler

atio

n, g

4

6

8

n, m

m 200

400

cele

rati

on, g

ARGh= 101 6 mm

0.03 0.04 0.05 0.06 0.07 0.08Time, sec

0

500

1000

1500

Impa

ct F

o

Impact loadHammer AccelerationDeflectionSpecimen Acceleration

-10

0

10

Ham

mer

Acc

e

-2

0

2

Def

lect

ion

-200

0

Spe

cim

en A

cc

h= 101.6 mm

23-Dec-09

17

Safety aspects of Jet Engine casing Containment system FBO event- Fan Blade out

US Airways- Landing on the Hudson, Jan 2009 High Speed Testing of Kevlar 49 Fabric

Data Acquisition System

Signal Conditioners and Controllers

Laser Extensometer

Table

Grip

Grip

Load Cell

Stroke

Piezoelectric Force Transducer

Personal Computer

Command SignalsLVDT & Servo-Valve

Personal Computer

FAA Sponsored Program: LS-DYNA Implemented Fabric Material Model Development for Engine Fragment Mitigation

Test Setup Tensile Properties under static and high speed conditions

23-Dec-09

18

Test Response at Different Strain Rate

300

400

ess,

ksi

Strain Rate, s-1

212230686897101

300

400

ess,

ksi

Strain Rate, s-1

212230686897101

Stress vs. Time Stress vs. Strain

0 0.0004 0.0008 0.0012 0.0016 0.002Time, sec

0

100

200

Tru

e S

tre 101

92166167167166

0 0.02 0.04 0.06True Strain, in/in

0

100

200

Tru

e St

re 10192166167167166

Kevlar Fill and Warp Cross-sections under load

104

=1.0 %

=0.0 %

=1 5 %=1.5 %

=2.0 %

Warp Cross-sectionFill Cross-section

Constitutive Relation of Yarn105

• Kevlar Yarns are assumed to be transversely isotropic

• Constitutive relation can be defined in terms of five material constants

• UMAT for solid elements

1113121111

000

000

SSS

SSS

3

2

1

Yarn Model

80000

23

31

12

33

22

1211

44

44

331313

131112

23

31

12

33

22

00000

05.00000

005.0000

000

000

SS

S

S

SSS

SSS

111

1

ES

1

1212 E

vS

1

1313 E

vS

333

1

ES

1344

1

GS

0 0.01 0.02 0.03 0.04 0.05

Strain, in/in

0

10000

20000

30000

40000

50000

60000

70000

Stre

ss,

psi Elastic

Region

Warp Direction (11)

E11

1

CrimpRegion

E11crp

Micromechanical model of Kevlar fabric 106

•modeling fill and warp yarns and capturing yarn to yarn interaction.•modeling of contact surfaces as well as mass scaling.•BCs: Left end of the fabric is fixed and velocity is applied on right end.• Both contact types (SOFT = 1 & 2) were used

LG610 Results107

LG610 Experimental (16.9%)

Single Layer

(20.7%)

Multi Layer

(18.3%)

LG689 Results108

LG689 Experimental (47%) Single Layer

(37%)

Multi Layer

(31%)

23-Dec-09

19

LG657 Results109

LG657 Experimental (100%) Single Layer

(100%)

Multi Layer

(100%)

LG657 Results110

LG657 Experimental (100%) Single Layer

(100%)

Multi Layer

(100%)

LG657 Results111

Conclusions

Our generational challenge is to meet the demand through sustainability, intelligent construction practices, novel product manufacturing, in addition to promotion and use of alternate, and economical sources for construction materials.

The processing method has a significant influence on the mechanical behavior of fabric-cement composites.

The pultrusion process significantly improves the tensile behavior of fabric-cement composites compared with cast composites, mainly for fabrics made from multifilaments.

Strain hardening behavior even when the modulus of elasticity of the yarn is relatively low.

A range of sustainable products can be developed. Integration of mechanics, materials, and manufacturing techniques

allows development of new applications for structural engineering

Acknowledgements

National Science Foundation, Binational US Israel Science Foundation, SRP, Salt River Project, St. Gobain Technical Fabrics

Colleagues, former and current students: Calvin Young, Cheng Yu Li, Joanne Situ, Rajashekar Vodela, Andrew Pivacek, Garrett Haupt, Jitendra Pahilajani , Nora Singla, Sachiko Sueki, Alva Peled, Dnyanesh Naik Chote Soranakom Juan Erni Mustafa GencogluDnyanesh Naik, Chote Soranakom, Juan Erni, Mustafa Gencoglu, Chote Soranakom, Della Roy, Sandwip Dey, Subramaniam Rajan

23-Dec-09

1

Sustainable Homes- Application of Steel ppFiber Reinforced Concrete for

Elevated Slabs & Low Cost housing

Barzin Mobasher, Arizona State University, Tempe, AZXavier Destrée,Belgium

Chote Soranakom, IMMS, Thailand

Invited Talk, Hong Kong Polytechnic University, Nov. 23, 2009

Research and discovery lags when the societal need embraces worthy ideas

Quite often, research is used to validate ideas that are borne out of the need. (Science of Thermodynamics was developed long after the steam engine’s adoption)

For ideas to become tangible and acceptable, one has to g p ,establish their truth value.

Truth however is first ridiculed, then opposed, and finally evident.

Applications of SFRC in Elevated Slabs

Construction Methodology

Full scale testing of elevated slab

Round panel Testing

Inverse analysis to obtain material parametersparameters

Proposed Design Methods

Conclusions

Applications of Fiber Reinforced Concrete

Fiber reinforced concrete are primarily used for applications that toughness of materials are of concern

First floor, elevated slab Elevated slabs

Advantages of SFRSS systemsPumping Reinforcement -I

– Eliminate double layers of rebars and stirrups fabrication, installation.

– Removal of congestion

– Time savings of several weeks for projects larger than 10,000 m2

– No Cranes for lifting rebars

– Installation using laser screed machines

Si lifi ti t j b it d h i l d l b i t i t k– Simplification at jobsite reduces physical and labor intensive tasks

– Eliminate or reduce drop panels

– Safety improvement

Advantages of using SFRSS systemsPumping Reinforcement- II

– Reduction in labor force and finishing personnel

– 30% cost saving vs. traditional methods

– Shrinkage cracking control

– Bay areas larger than traditional areas

– Detailing cost reduction

23-Dec-09

2

Steel Fiber Reinforced Concrete

Composition Amount

Cement Type I 350 kg

Fly ash 60 kg

Aggregate (1 1:1) 1800 kg

Two volume fractions

– Vf = 80 kg/m3

– Vf = 100 kg/m3

Aggregate (1.1:1) 1800 kg

W/C < 0.5

Supper plasticizer 1.25 % by Vol.

BEMAT 400mm raft 50kg SF08, 2006

DittonNams-Superstore elevated slab Daugavspils, Latvia25 ft span, 10inches slab,200psf UDL

165lbs/cu.yd Tabix 1.3/50 140ksi Steelfibers

LKS struct.engineers headoffices, 5 floors 50000 sq.ft total ,Mondragon, Spain,

27ft span, 11 inches thickness, 140psf UDL165lbs/cy.yd Tabix 1.3/50 140ksi steelfibers

Veterinary hospital, Hannut Belgium17ft span, 7 inches slab

100lbs/cu.yd 1/60 210ksi steelfibers

Pumping SCC with 165lbs/cu.ydTabix 1.3/50 140ksi steelfibers

23-Dec-09

3

Full Scale Tests up to date

# Year Location # x & y spans # of columns

span length,

mm

Thickness mm

column size

mm x mm

dosage rate

of steel fibers, kg/m³

span/depth ratio

1 `94 Ternat,Belgium

3 / 3 / 16 3100 160 210 x 210 45 19

2 `00 Townsville,Australia

3 / 3 / 16 3100 160 210 x 210 45 19

3 `04 Bissen,Luxembourg

3 / 3 / 16 6000 200 300 x 300 100 30

4 `07 Tallinn,Estonia

3 / 3 / 16 5000 180 300 x 300 100 28

Full Scale Elevated Slab

Square grid floor 18.3 m x 18.3 m (3 bays each direction)

mix Vf=100 kg/m3

Slab thickness of 0.2 m

Column size of 0.3 m x 0.3 m

Bissen site Construction and Field Testing

Cast in place SFRC

Use minimum reinforcement along the column lines to prevent progressive collapse

Test rig centre span

Bissen test rig underneath Tallinn, Estonia , Test site Service Load, 4kNm² udl, (83 psf)

23-Dec-09

4

Center Point loading Bissen Test Corner span center point loading Test

120kN minute cracking at Tallinn test 320kN 0.55 mm crack opening more than 3 x the first crack load!

500kN negative moment cracking 595 kN edge cracking

23-Dec-09

5

Full scale Test Results Problem Statement

There is no standard analytical model to evaluate material properties

Practicing engineers rely on yield line theory or plastic analysis to evaluate strength– This method assumes a constant plastic strength and ductile

deformation, which may be suitable for ductile RC structures but may not for low-medium discrete fiber reinforced concrete

The objective of this study is to evaluate the existing analysis and design approach (yield line method) with a more advance nonlinear finite element analysis – use concrete damaged plasticity model that capable of simulating

cracking in brittle material

Round Panel Test

A round panel test is used to evaluate SFRC

Test setup– displacement control

– continuous support

– center point load

– measure load vs. mid span deflection

Dimensions– clear diameter 1500 mm

– thickness = 150 mm

– stoke diameter = 150 mm

Round Panel Tests

Deflection measuringdevice

Plastert

S

D

F

S

D= S=t = 150, 200 mmr=150

1660, 2100 mm1500, 2000 mm

r

Crack patterns in the Round Panel Specimen- 100 Kg/m3 steel fibers Typical Crack Patterns

Vf = 80 kg/m3

Sample 8-02Vf = 100 kg/m3

Sample 1-07

The test reveals unsymmetrical multiple radial crack patterns

23-Dec-09

6

FEM Response of a Full Model

In elastic range, the deformation is symmetrical such that symmetric criteria can be imposed as boundary conditions to improve the efficiency of the model

In plastic stage, strain energy density localizes in crack band regions

Moment distribution at various stages

40

50

m/m

m)

M (Vf 100 kg/m3)

M(Vf 80 kg/m3)

before cracking, the radial and circumferential response are almost the same.

After specimens crack, they continue to increase and reach the peak capacity.

Then the strength of the radial

0 0.0001 0.0002 0.0003

Curvature (mm-1)

0

10

20

30

40

Mo

me

nt p

er

Len

gth

(kN

-mm

Mr (Vf 100 kg/m3)

Mr (Vf 80 kg/m3)

Then the strength of the radialmoment decreases abruptly while the circumferential moment decreases gradually.

Test Results and Averaged Response

Load deflection responses of two mixes

160

200

Vf = 80 kg/m3 Vf = 100 kg/m3

200

0 10 20 30Deflection (mm)

0

40

80

120

160

Load

(kN

)

Samples 1-6Average

0 10 20 30Deflection (mm)

0

40

80

120

160

Load

(kN

)

Samples 1-9Average

Material Properties from Calibration

The first cracking tensile strength from -w are compared well with the plastic strength ftu from yield line theory

2

2.5

)

ftu = 2.11 MPa(yield line prediction)

2

2.5

)

ftu = 2.37 MPa(yield line prediction)

0 0.5 1 1.5 2Crack Width (mm)

0

0.5

1

1.5

2

Te

nsi

le S

tre

ss

(MP

a)

-w relationship,E = 20 GPa, = 0.15 (inverse analysis FEM)

0 0.5 1 1.5 2Crack Width (mm)

0

0.5

1

1.5

2

Te

nsi

le S

tre

ss

(MP

a)

-w relationshipE = 24 GPa, = 0.15 (inverse analysis FEM)

(y p )

Vf = 80 kg/m3 Vf = 100 kg/m3

Finite Element Simulation (1/4 Model)

Use symmetry condition and model only the upper left of the flat slab for efficiency reason

Use shell element S4R for plate bending problem

Use calibrated material parameters of mix Vf=100 kg/m3

Assume self weight of concrete = 2400 kg/m3

23-Dec-09

7

Major crack at Bottom Surface

FEM shows symmetrical cracks in x and y directions

Experiment shows major cracks propagate in y-direction more than the x-direction– Material placed in y–direction may be weaker than the x-directions

Major crack at Top Surface

FEM shows symmetrical cracks along the column lines in both x and y directions

Experiment shows major cracks propagate along the column line in y-direction– Material placed in column line y–direction may be weaker than the

x-directions

Load Deflection Response

600

mulation Response Experiment FEM Yield line

FEM predicts stiffer response and higher capacity than the experiment

Yield line predicts the strength between the experiment’s and the FEM prediction’s

0 50 100 150Mid-Span Deflection (mm)

0

200

400

Lo

ad

(kN

)

Simul

Experiment

line

Pcr 230 kN 401.2 kN -

cr 7 mm 3.0 mm -

Pult 470 kN 542.8 kN 536.1 kN

Material model Strain softening

Compression model Tension model

Stress and Strain Distribution

c=cr

kd

d

kd

d

c=c

r

cr

d

kd

cr

cr

c=cr

t c

1Fc1

yc1

t1Ft1

yt1

t c1

Fc1

yc1

Ft1

yt1

Ft2

yt2

t1

t2

t c1

Fc1

Fc2

Ft1yt1

Ft2

yt2

yc1yc2

t1

t2

0 < < 1 1 < < <

Moment Curvature Diagram

Incrementally impose 0 < t < tu

Strain Distribution

Stress Distribution

F = 0, determine k

M = Ciyci+ Tiyti and =c/kd

1 10

kd

c cF b f y dy

1 101

kd

c cc

by f y ydy

F

stress

k

d

0 < t < tu

strainc

C1

C2

T1

T2

T3

M M

Moment curvature diagram

23-Dec-09

8

Model for strain softening

Stage k M’=M/Mcr ’=/cr

1

0 < < 1

1

2

2k

2 2

2

2 ( 1) 1

23 2

2

(2 3 3 2)3 (2 1)

kk

2k

Stage k M’=M/Mcr ’=/cr

1

0 < < 1

1

2

2k

2 2

2

2 ( 1) 1

23 2

2

(2 3 3 2)3 (2 1)

kk

2k

crcr

2 =

d

1 < < 2 ( 1) 1 2

< cu 2

22 ( ) 2 1

22 3 2

2

(3 3 3 2)3 (2 1)

kk

2k

Soranakom, C., and Mobasher, B., “Closed Form Solutions for Flexural Response of Fiber Reinforced Concrete Beams,” ASCE, Journal of Engineering Mechanics, August- 2007

2cr cr

1M = bd E

6

1 < < 2 ( 1) 1 2

< cu 2

22 ( ) 2 1

22 3 2

2

(3 3 3 2)3 (2 1)

kk

2k

2cr cr

1M M M ' = bd E M '

6

Softening Region- Residual tensile strength,

0.3

0.4

0.5

xis

dept

h ra

tio, k

= 10

cu = 0.004

tu = 0.0152

3

zed

Mom

ent,

M'

0 35

=0.68

=1.00

M’= 1.910

M’=1 0145

M’=2.727

0 4 8 12 16Normalized top compressive strain,

0

0.1

0.2

Neu

tral

ax

=0.01=0.35

=0.68

=1.00

=0.18

0 20 40 60Normalized Cuvature, '

0

1

Nor

mal

iz

=0.01

=0.35

=0.18

crcr

2 =

d

2cr cr

1M = bd E

6

M '( ) = 3 +

M’=1.0145

M’= 0.530

M’=0.03

Calculation Example

What is the moment capacity of a fiber reinforced concrete beam? Given that:– b=4 in, d=4 in

E = 3x106 psi = 300 psi = 150 psi

2ult cr

1M 3 bd E

+ 6

– E = 3x106 psi, cr = 300 psi, p = 150 psi– fc’ = 4500 psi, cy ~ 0.8fc’

Calculations– = p/cr = 0.50– = cy/cr = 12– M’∞ = 3/(+) = 1.44 (no unit)– Mcr = 1/6bd2cr = 3,200 lb-in– M∞ = M’∞Mcr = 4,600 lb-in– Mu = 0.90M∞ = 4,150 lb-in Moment capacity

Development of Design Guides

Deflection Softening-Hardening Transition

Min Fiber loading:

crit ( = 10) = 0.355

0 5

110

150

1

2

3

Normalized Moment at Infinity

Min

f/Mcr

3 1crit

Typical SFRC: = 0 – 1 and = 5 – 15

Required Residual strength for a given moment

M’∞ = 0.1 – 2.5 and = 5 - 15

0

0.5

5 muomega

' 3M

'

'3

M

M

0

12

3

5

10

150

0.5

1

Minf/Mcr

Normalized Post Crack Tensile Strength

omega

mu

(req

uire

d)

2cr cr

1M = bd E

6

Theoretical Flexural Strength for strain softening FRC

2n cr

1M 3 bd E

3n n p cr uM M M

'f

''

'

0.850.126866

6.7

cy cc

cr c

ff

f

n cr+ 6

15 55

2cult cr'

c

fM bd E

. +2 f

Plastic analysis, Round Panel- Fixed or Free

D

max

D

max

Fixed edges

Free edges

max

max

int extW W

4ult PP M 2ult PP M

24

2 3ult

Pq RR

M

2

12ult

Pq R

M

Concentrated Load

Distributed Load

23-Dec-09

9

Example Application for Three point bending Beams Plastic analysis Beam and Panel Flexure

q

LNNN

L

L/2L/2

L/2

L

int extW W

max

q

22 2 2

2 2P P

LM M [ q ]

L

2

8ult

Pq L

M

L/2

max

max

Modes of Failure

max

w

M p

M 0

M >0p

M <0p

Precast panels

Panels are made of plain concrete and steel rebar to be installed on site

Installation of pre-cast water tank

Panels are assembled on site

The wall joints are connected using bolts and epoxy

The base slab is connected to the periphery walls by friction through slots

23-Dec-09

10

Analysis of Wall Panels

Assume continuous wall, pin connection at the bottom and free at the top

Lateral water pressure in ultimate andultimate and serviceability limit states

Critical Internal Forces

Critical moment, shear, and axial forces– Horizontal

– Vertical

Design thickness and reinforcement for both– Ultimate

– Serviceability

Cast in Place Water Tank

For small dimension, the cast in place water tank is usually used.

Finite Element Analysis

Lateral loading– Water– Earth pressure– Surcharge

Finite element model– Shell elements

Analysis Results

Load Case1:– 1.4 Self weight +

1.4 Water pressure

– Moment in short span direction SM1

Load Case2:– 1.4 Self weight +

1.7 Earth pressure + 1.7 Uniform pressure due to surcharge

– Moment in short span direction SM1

Septic Tanks- 4 cm thickness with FRC vs. 12 cm with WWF

23-Dec-09

11

Lightweight, Durable, and economical Low income housing

Interior and exterior Wall panels plus roof are formed as one system Full frame & Roof form set up

Subdivision development Rebar Set up

23-Dec-09

12

1 house per day with a crew of 8

Conclusions

The tensile crack width relationship obtained from the inverse analysis correlates well with the yield line prediction

Plastic analysis design methodologies which were developed more than 5 years ago can be applied to fiber reinforced concrete structures built with Steel fibers.

Finite element method, when used in conjunction with simplified material models can be effectively used to verify the design geometry for a variety of structural applications.

Acknowledgements

US National Science Foundation, NSF, Award # 032466903, Program Manager, P. Balaguru.

Prof. Dr.-Ing. U. Gossla, Aachen University of Applied Sciences.

Gossla, U., Development of SFRC Free Suspended , , p pElevated Flat Slabs – Analysis and Design Recommendations. Research Report, Aachen University of Applied Sciences, 2005.