FRP

Strengthening of Concrete Structures Using

Reinforced Concrete Enlargement Systems

Tarek Alkhrdaji, PhD, PEVice President Engineering Services

Introduction to Structural Strengthening Strengthening Process FRP Strengthening Concrete Enlargement Micro-Reinforced Concrete

Design Approach Experimental Verification Applications

Case Studies

Presentation Outline

PG Punching Shear Failure

New DemandExisting Capacity

The Strengthening Process

What is actual As-built Condition?

Damage level? Existing stress condition Complex analysis Construction means

methods and materials Composite behavior

requirements & detailing

What is actual As-built Condition?

Damage level? Existing stress condition Complex analysis Construction means

methods and materials Composite behavior

requirements & detailing

Design strategies Specifications Submittal & review

processes Quality Assurance

Design strategies Specifications Submittal & review

processes Quality Assurance

Steel Plate Bonding

Span shortening

External Post-Tensioning

New Reinforcement

Section enlargement

Strengthening Process- Conventional Options

% Use of Strengthening Systems

FRP Composites

External Post Tensioning- External in enlarged section- External

- Internal in drilled/cored holes

Enlargement of Section

Supplemental Steel (Plate bonding or support)

~50%

~50%

ANCHORS?

Steel Plate Installation Dry-Fitting ComponentsSteel Plate Installation Dry-Fitting Components

Strengthening with FRP Composite

Flexural Strengthening

Bottom Reinforcement

Column Strengthening

Underground PipelinesUnderground Pipelines

FRP Design Guidelines

440.2R-08 ACI 440.2R-08

FRP General Design ConceptsEffectiveness of FRP

f f

cu cu

Strain compatibility design approach

FRP design strength can be 50% of published ultimate strength (0.5 ffu)

Strength vs. Ductility

sys

ssysy

syss

for65.0

005.0for005.020.0

65.0

005.0for90.0

ACI 318:A section with lower ductility should compensate with a higher reserve of strength

0.90

0.70

Steel Strain atUltimate

sy 0.005

0.65

0200

400

600

800

1000

0 100 200 300 400 500 600 700 800 (10e-06 1/mm)

M

(

k

N

-

M

)

Original RC Beam

1 ply FRP

3 plies FRP6 plies FRP

Effect of Adding FRP Plies

Carbon

1000

2000

3000

4000

0

5000

T

e

n

s

i

l

e

S

t

r

e

s

s

(

M

P

a

)

CarbonCarbon

1000

2000

3000

4000

0

5000

T

e

n

s

i

l

e

S

t

r

e

s

s

(

M

P

a

)

FRP Effective Design Strain(FRP Bond Limit)

fuff

cfd tnE

f 9.0'41.0 Externally bonded fiber and laminates (SI units)

fd fu

fd varies from 0.5fu to 0.9fu

CASE STUDIES

- FLEXURE -

New Hospital

Parking toOffice Space

New Hospital

Parking toOffice Space

New HospitalParking to Office SpaceNew Hospital

Parking to Office Space

FRP Sheets

New HospitalParking to Office SpaceNew Hospital

Parking to Office Space

Case Study - ChimneyCase Study - Chimney

Existing Capacity vs. DemandExisting Capacity vs. Demand

0

25

50

75

100

125

150

0 500 1000 1500 2000 2500Moment [kN-m x 103]

E

l

e

v

a

t

i

o

n

[

m

]

Flexural Demand

Existing Moment Capacity

Areas requiring strengthening



Nominal CapacityNominal Capacity

' ' ' ' '1 2 3 4

12

0 01

cos

2st

n u

n

f f f f f f f f f fi fii

M P R C S S S S

nt w E d c nt w E d c

Concrete and Steel Contribution

FRP Contribution= 0.85

FRPs

s t

wf

cy

R

ACI 307-08Design and Construction of Reinforced Concrete Chimneys

Strengthening LayoutStrengthening Layout

0.0 m

3 PLIES FULLCOVERAGE (FRPON BOTH SIDES)

20.0 m

29.0 m


99.0 m


NO FRP REQUIRED

3 PLIES FULL COVERAGE(FRP ON INTERIOR SIDE)105.0 m

108.0 m

117.0 m

2 PLIES 600 mm WIDE OFFRP AT 900 mm O.C.(FRP ON INTERIOR SIDE)

LONGITUDINAL CHIMNEY SECTION

111.0 m

2 PLIES FULLCOVERAGE (FRP ONINTERIOR SIDE)

84.0 m

63.0 m

2 PLIES FULLCOVERAGE (FRP ONBOTH SIDES)

23.0 m 1 PLY FULLCOVERAGE (FRP ONEXTERIOR SIDE)

NO FRP REQUIRED

140.0 mNO FRP REQUIRED

STRENGTHENINGAT OPENING WITH

STEEL PLATES(fy = 420 MPa)

CONCRETEENLARGMENT AT

CHIMNEY BASE

Parking GaragePrecast Double Tee and Corbel

Strengthening

Existing Conditions

Precast Tee FRP Strengthening

Corbel FRP Strengthening

Strengthening with Concrete Enlargement

Concrete Enlargement

Create composite behavior via:1. Horizontal shear transfer

a. Installation of steel dowels

b. Profiling of concrete surface (CSP-7)

2. Prepare surface to open pores

3. Placement techniques to force intimatecontact between exiting and new concrete

Enlargement Specifying & Measuring Surface Preparation

ICRI SurfaceProfile Chips

Enlargement Specifying & Measuring Surface Preparation

CSP-7

Enlargement-Place new materialand force into pores of existing concrete (Form&Pump)

NewExisting

Enlargement Transfer Girder

Enlargement

Enlargement

2-3 psiBond Line

10-15 psi

Enlargement

Enlargement Materials- SCC

28 in

Sounding and Bond Tests

Sounding Sounding

`Ping

Confirming Bond- Quality ControlConfirming Bond- Quality Control

Pull testPull test

Core Through Enlargement Quality Control-Quality Control-

Enlargement Original

BondLine

FailurePlane

1 MPa

fc of materialsCoring depth and diameterDollie size Perpendicular dollie & coreDollie adhesive

1 2 3

Transfer Girder- Structural Defect

Transfer Girder - Formwork

Enlargement of Columns for Higher LoadsEnlargement of Columns for Higher Loads

BYU Pedestrian Bridge

New Pedestrian Bridge Extension to be Added

New Pedestrian Bridge Extension to

be Added

Bridge: Existing Condition

Total Length = Approx. 410m

Width = 4m

Span (Work Area) = 19m

Existing Condition- 3D ModelingExisting ConditionExisting Condition-- 3D Modeling3D Modeling

Span under Modification

Modified Condition- 3D ModelingModified ConditionModified Condition-- 3D Modeling3D Modeling

Removed Portion of Beam

Enlarged Beam with

New PTConstruction joints where Existing PT is anchored

Top FRP Bars at Supports20

'-0"

COLUMN 2

18'-0"

20'-0"

16'-0

"

COLUMN 3

PEDESTRIAN OVERPASS PLAN VIEW: TOP FRP LAYOUT

8 #4 CFRP BARS AT12" O.C. (MIN.) ON TOP OF SLAB

8 #4 CFRP BARS 38'-0" LONGAT 12" O.C. (MIN.) ON TOP OF SLAB

4 #4 CFRP BARS38'-0" LONGAT 3" O.C. (MAX.)ON BEAM



27'-

9"

INSIDE RADIUS = 33'-9"

OUTSIDE RADIUS = 44'-2"

15'-4 3/4"

CONSTRUCTION JOINT(CJ2)

INSIDE FACEELEVATION

(SEE DETAIL BELOW)

12"

CONSTRUCTION JOINT(CJ1)

22'-

2"

15'-4"18'-0"

CJ2

4 #4 CFRP BARS38'-0" LONG

AT 3" O.C. (MAX.)ON BEAM

3'-0" LAP (MIN.)

INSIDE FACE ELEVATION: CFRP BAR LAYOUT

13'-4"1'-0"

5 #4 CFRP BARSAT 3" O.C.

13'-4" LONG

26'-11"

5 #4 CFRP BARSAT 3" O.C.

13'-4" LONG 5' MIN. OVERLAP

5' MIN. OVERLAP

8" CONCRETEENLARGEMENT

8'-0

"

10'-0

"

COLUMN 3

34

2

1

Bottom FRP Sheets

COLUMN 2

COLUMN 3

PEDESTRIAN OVERPASS PLAN VIEW: BOTTOM FRP LAYOUT

1 PLY 24" WIDE10'-6" LONG AT 36" O.C.(7 STRIPS TOTAL)

1 PLY 24" WIDE11'-7" LONG AT36" O.C. (TYP.)

24"

24"

1 PLY 24" WIDE25'-9" LONG AT36" O.C. TYP.)

1 PLY 24" WIDE22'-0" LONG AT

36" O.C. (TYP.)

12'-7

"

9"

12"

4

2

34

2

1

Typical Section

SECTION

1'-3" 10'-0" 1'-3"5

'

-

6

"

12'-6"

5'-0"1 PLY 24" WIDE25'-9" LONG (TYP.)

8 #4 CFRP BARS38'-0" LONG AT 12" O.C.


AT 3" O.C. (MAX.)


AT 3" O.C. (MAX.)

3"

4

PT Enlargement Details

BRIDGE ELEVATION: REINFORCEMENT LAYOUT(NTS)

COLUMN 2CJ 1 9'-10"22'-2"8'-0"

B

E

A

M

O

P

E

N

I

N

G

SECTION A-A: SECTION DETAIL

1'-3"

5

'

-

6

"

3

"

8"

#5 L-DOWEL AT 12" O.C.WITH 8" EMBEDMENT

2 #7 BOTTOM BARS

#5 SKIN BARS AT 11" O.C.VERTICALLY

#5 L-DOWELS AT 11" O.C.VERTICALLY WITH 6" EMBEDMENT(MIN.) INTO PARAPET

8"EMBEDMENT

7 0.6" STRANDP-T TENDONS

2 #7 TOP BARS

1'-3"

5

'

-

6

"

3

"

8"

#5 L-DOWEL AT 12" O.C. WITH8" EMBEDMENT

2 #7 BOTTOM BARS

#5 SKIN BARS AT 11" O.C. VERTICALLY

8"EMBEDMENT

7 0.6" STRANDP-T TENDONS

2 #7 TOP BARS

A

P

P

R

O

X

.

2

7

"

6"

#5 L-DOWELS AT 11" O.C.VERTICALLY WITH 6" EMBEDMENT(MIN.) INTO PARAPET

2" DEEPTRENCH

A

A

B

B

SECTION B-B: END SECTION

10 1/2"

24 1/4"

7 1/2"

5'-0"THICKENED WALL

TRANSITION(SEE SHEET S11)

2 #7 TOP BARS#5 L-DOWELS AT 12" O.C.HORIZONTALLY WITH 6"EMBEDMENT (MIN.) INTO PARAPET

#5 VERTICAL BARS AT 12" O.C.WITH 8" EMBEDMENT(MIN.)

2 #7 BOTTOMBARS

#5 LONGITUDINALSKIN BARS AT 11" O.C.VERTICALLY

5

'

-

6

"

4

'

-

6

"

PT Concrete Enlargement

All-thread Bars

P-T Anchorages


Strand Stressing Lower P-T Tendon

Grout Tubes Installed


P-T Tendons Grouted Finished Product

PART 2Micro-Reinforced Concrete

Micro-Reinforced Concrete System



Cementitious Slurry Infiltration


Infiltrated Cage


Standard Components

PlasticizerCement Premix

Slurry infiltrated Micro-reinforced Concrete

WaterSand

Self Compacting Slurry

WeldedWire Mesh

+


High Ductility


Thin & Light

Energy Absorbing No Fragments

High Durability

High Ductility

Benefits


Compressive Strength = 16,000 psi 23,000 psi

Tensile Strength = 1,300 2,900 psi

Shear Strength = 1,000 2,300 psi

Youngs-Modulus = 4.200 ksi 5.800 ksi

Ductility factor > 10 (ultimate strain/ yieldstrain )

Technical Data


Strain Compatibility


2

2

6"

Ducon (thickness varies)

11'-0"

10'-6"

10'-0"

24"

6" 7"

Ducon(Thickness 1")

Slab SF1-D

Slab SF1-D & SF5-D

24"

6" 8"

Ducon(Thickness 2")

Slab SF5-D

Slab Details


Substrate Surface Scarifier

Slabs: Surface Preparation

CSP-7 Surface Profile


10 or 20 Layers of Ducon Mesh Secured Using Tie Wire and Duplex Nails

Slab SF1-D: 1 Ducon


Slabs Fabrication: Placing DUCON Slurry into Forms


Slab: Finished Product


Cracking Pattern


Test Results

0

2000

4000

6000

8000

10000

12000

14000

0 1 2 3 4 5 6Deflection (in)

L

o

a

d

(

l

b

)

SF1-D Experimental SD1-D

ACI Predictions

SD1ACI Predictions

SF1Experimental

1 Thickness


Test Matrix2 Thickness

0

5000

10000

15000

20000

25000

0 0.5 1 1.5 2 2.5 3

Deflection (in)

L

o

a

d

(

l

b

)

SF5-D Experimental

SD5-D ACI

Predictions

SD5ACI

Predictions

SF5Experimental


12"

4"

BS5-D

36"

12"

15 1/2"

17 1/2"

U-Shape Ducon(Thickness 1.75")

16"

1

1

4"

U-Shape Ducon(thickness varies)

11'-0"

10'-6"

10'-0"

Beam BS2-D & BS5-D

12"

4"

Beam BS2-D

U-Shape Ducon(Thickness 1")

36"

12"

14"

16 3/4"

T-Beam Details


Roughened Surface to Amplitude

Surface Preparation


Beams: HUS-H Screw Anchor Layout


Formwork Installation


Finished Product


Test SetupFour-Points Bending Test


Test Results

0

50000

100000

150000

200000

250000

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7Deflection (in)

L

o

a

d

(

l

b

)

1.75 JacketExperimental

1 JacketExperimental

BenchmarkExperimental


ApplicationsRepair & Strengthening


Seismic

Security WaterproofingStructural Strengthening

Applications


Thin OverlaySurface Repair / Slab Strengthening


2.4 thick

Column Enlargement


)

Precast encasement before infiltration of RCColumn Forms


DUCON Column Forms


ApplicationsForce Protection (Blast Mitigation)


Contact Detonation Test Results

RC

Breach, Spall and Projectiles NO Breach, NO SpallNO Projectiles

Front/ Attack Side


RC

Rear Side

Contact Detonation Test Results

DUCON


120 mm Mortar Impact

Mortar Round Detonation TestingFragmentation Protection


Column Blast UpgradeDynamic Finite Element Analysis


CombinationofDUCONandReinforcedConcrete@FullHeightColumns

Column Blast UpgradeColumn Jacket


Column Blast UpgradeColumns Required Upgrades Exterior View


Column Blast UpgradeMesh Installation - Full Height


Column Blast UpgradePartially Formed Column with Injection Points


Column Blast UpgradeCompleted Full Height Column Jacket


Thank You

Tarek Alkhrdaji, PhD, PEVice President Engineering Services

[email protected]: (410) 340-3260

FRP

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