strengthening of concrete structures - seaog.org & tank construction ... rebar discontinuous 5...

Strengthening of

Concrete

Structures

Shaun Loeding, P.E.Director

Strengthening Division

Overall Intent ???

“Design and implement structural solutions

based on our experience and technologies.”

Shaun Loeding, P.E.

Director - Strengthening Division

Solutions that integrate products, engineering, and construction

Engineering Support Services

State of the Art ProductsSpecialty Contracting

Total Group

Annual Revenues $400 million

Offerings Products – Engineering – Construction

Employees 2,500 +

Products & Engineering $50 Million

Regional Technology Centers Baltimore, Dallas, & Houston

Construction

Annual Revenues $350 Million

ENR Ranking Largest Concrete Repair Contractor &

27th Largest Specialty Contractor

Projects 2,000-2,500 annually

Typical Range $2,500 to $30 Million

Labor Union & Open Shop Multiple Crafts 2,000-2,500 employees

Markets Served North America & Middle East

Quick Facts

Quick Facts

International Offices:

Abu Dhabi

Dubai

Qatar

Corporate HQ:

Hanover, MD

North America Offices:

Baltimore

Baton Rouge

Chicago

Dallas

Denver

Detroit

Ft. Lauderdale/Miami

Hartford

Kansas City

Lake Charles

Long Island

Los Angeles

New York

Philadelphia

Pittsburgh

San Francisco

Sarasota/West Florida

Springfield

Offices

Design-Build Construction Chimney & Stack Construction

Silo & Tank Construction

Pre-Engineered Structures

Repair Services Concrete Repair

Fireproofing

Force Protection

Pipe Rehabilitation

Strengthening

Corrosion & Cathodic Protection

Refractory Linings

Equipment & Pump Foundations

Moisture Control & Waterproofing

Building Envelope

Historic Restoration

Maintenance Services

Industry Leading Specialty

Contracting Services for New & Existing Structures

Repair Services Concrete Repair

Fireproofing

Force Protection

Pipe Rehabilitation

Strengthening

Corrosion & Cathodic Protection

Refractory Linings

Equipment & Pump Foundations

Moisture Control & Waterproofing

Building Envelope

Historic Restoration

Maintenance Services

Industry Leading Specialty

Contracting Services

State of the Art Products

Engineered Solutions

Products & Systems Strengthening

Force Protection

Pipe Repair & Upgrade

Corrosion Control

Moisture Control

Concrete Restoration

Equipment Foundations

Post Tensioning

Engineering Support Investigative

Condition Assessment

Engineering Product Customization

Design – Assist

Specialty Full Design

Agenda

Introduction

FRP (fiber reinforced polymers)

- Most common uses for FRP

- Design strategy (ACI 440.2R-08)

- Installation techniques and QA/QC

- FRP limitations & fire protection

- Case Studies

Conventional Techniques

- Section Enlargement

- External Post Tensioning

New Strengthening Technologies

(DUCON – micro-reinforced concrete)

Why Strengthen??

Construction Defects

Design Deficiencies

New Loads

Deterioration

Seismic Upgrades

Blast Upgrades

Strengthening =

Upgrading Structural Capacity

Design-Development Conceptual designs and associated

budgets

Specification support

Aid in overall engineering and strengthening analysis

Site visits

Solution/repair strategy

Construction Final design calculations and shop drawings

(PE stamped/sealed upon request)

QA/QC and Safety Program – project specific

Trained, certified and experienced installers

Direct Services

FRP Composite – what is it ???

FRP = Fiber-Reinforced Polymer

Composite = two or more materials that when combined

create one composite behaving system

(fiber + epoxy = composite, with new and distinct properties)

OTHER NAMES USED: Carbon fiber

Carbon FRP (CFRP) or Glass FRP (GFRP)

Fiber reinforced composite (FRC)

Fiber wrap

Externally bonded FRP reinforcement

“Strengthening” Typically Carbon FRP (CFRP)

Upgrade flexure and/or shear capacity of member

CFRP = higher strength, higher material cost

FRP Applications

“Restoration” Typically Glass FRP (GFRP)

Corrosion protection, spall protection

GFRP = lower strength, lower material cost

NOTE: CFRP and GFRP = lightweight, low profile, corrosive resistant, durable

FRP Applications

CFRP strip – 1 layer, 12” wide = (1)-#5 rebar (60ksi) Typical application uses CFRP strips of 8”, 12” or 24” width

Typical application uses 1 to 4 layers of CFRP

CFRP may provide up to 40% additional capacity to an element Typical application requires 20%-25% additional capacity

CFRP does not stiffen an element i.e. does not aid in reducing deflections or aid in satisfying service conditions of

an element

“Rules of Thumb” –

flexural strengthening with CFRP

12”

440.2R-08

FRP Design Principles & Engineering Considerations

FRP Flexural Design Concepts

2

cdfAM 1

ssn

h d

b

c

ec

es fs

gf 'c

1c

2

1chfA ff

f

ffef

Strain in FRP?

LC

FRP – Design Strain Limits

“Peeling” de-bonding

effect at ends

“Un-zipping” de-bonding

effect at flexural cracks

20

40

60

80

100

120

140

160

180

200

0 0.002 0.004 0.006 0.008 0.010 0.012 0.014 0.016

Strain

Str

ess (

ksi)

Steel

GFRP

0

CFRP

Modulus, E:

Steel – 29,000ksi

CFRP – 12,000ksi

GFRP – 3,000ksi

Design – Stress/Strain Relationship

Ultimate (Rupture)

Flexural Design

DEFLECTION

LO

AD

Member

with FRP

Original RC

Member

“Supplemental Reinforcement”

FRP Strengthening Limits – ACI 440.2R

New 440.2R Loads:

1.1DL+0.75LL

New Ultimate Loads:

1.2DL+1.6LL

Existing strength without FRP should be able to support demand from load case

of 1.1DL+0.75LL (ACI 440.2R, Eq. 9-1)

DEFLECTION

LO

AD

Member

with FRP

Original RC

Member

“Supplemental Reinforcement”

FRP Strengthening Limits – Fire Event

New Service Loads:

1.0DL+1.0LL

(due to change)

New Ultimate Loads:

1.2DL+1.6LL

2Hr Fire

Reduced

Capacity

Existing strength without FRP should be able to support typical service loads

(1.0DL+1.0LL) after 2Hr Fire

Intumescent

(Burning-

ASTM E84)

Fire Protection Strategies

Protect FRP for Applicable Burn

Characteristics per ASTM E84

Intumescent Topcoat

(Flame spread & smoke density)

FRP Installation – General Procedures

Prepare substrate surface

Provide surface primer/thickened epoxy on prepared

substrate

Saturate fabric sheet

Install saturated fabric sheet

Provide coating

Substrate Preparation for Bond

Open pores!

1 2 3

1.Abrasive

blast2.Dustless

grinding

& vacuum

3.Water blast

& dry

Primer

Surface Preparation

Primer/Thickened Epoxy to Substrate

FRP Sheet Saturation

FRP Sheet Saturation

FRP Sheet Installation

Prepared substrate Saturated fabric

sheet

Primed

substrate

QC Acceptance Criteria

Bond

Pull of tests to determine bond strength to

concrete

Minimum 200 psi

Delamination

Limits of delaminated FRP area to ensure adequate

performance

Material Testing

Tensile tests of laminate from field

Tap Test

FRP Pull off Bond Test Requires Min. 200psi

Condo Building - multiple strengthening techniques

due to design defects

Slab Strengthening – FRP layout

Slab Upgrade – FRP strips

(positive bending)

Slab Strengthening

(negative bending)

Slab

Strengthening

Wall removal required

Condo Building - multiple strengthening

techniques due to design defects

Shear collars Column enlargement

New Penetrations in Existing Slabs

One direction

Two direction

New Slab Penetrations

Existing Concrete Joists

Precast Double Tees - Stem cracks

Install FRP Shear “U” Wraps

Guggenheim Museum

Guggenheim Museum

Guggenheim

Museum

Chip

Open

crack

Guggenheim Museum

Steel

T-Section

Rebar

Discontinuous

5”

Guggenheim

Museum

T-Bars

Guggenheim Museum Prior to insulation

and dry wall

Grout

Guggenheim Museum Thru wall detail

BondBond

Guggenheim

Museum

Web Wall

Bracket

Lack of plastic hinge confinement

MOMENT RESISTING FRAMES - Column failure

(Performance of an RC Corner Beam-Column Joint by Engindeniz et al., 2007)

Beam/Column shear strengthening

FRP Wrap – Increase Axial Load Capacity

Column Repairs - Low Strength Concrete

Enlarge FRP

Power Plant - Missing Seismic Steel

Power Plant - Missing Seismic Steel

Power Plant - Missing Seismic Steel

Power Plant - Missing Seismic Steel

FRP “Near-Surface Mounted” (NSM) Rod -

FRP “Near-Surface Mounted” (NSM) Rod -

CFRP Bar Installation Finished Product

NSM Rod- Bridge Decks ( I-75, Florida)

NSM Rod- CMU Wall Application

I-75 Rouge Bridge, MIColumn FRP Upgrade

Shear Upgrade with FRP

Completed Bridge Pier FRP Strengthening

FRP rod

Epoxy paste

FRP reinforcement

FRP Sheet

FRP Strengthening –

NSM Anchorage of Shear Reinforcing

Far Rockaway, Queens, NY – Elevated ‘A-Line’

Far Rockaway, Queens, NY – Elevated ‘A-Line’

Far Rockaway, Queens, NY – Elevated ‘A-Line’

Far Rockaway, Queens, NY – Elevated ‘A-Line’

Enlargement- “Composite Behavior”

NewExisting

Enlargement: Self-Consolidating Concrete

26-28”

Section Enlargement

F

F

NEW LOAD

Uplift

at Deviator

Dead end

Live end

External Post Tensioning Upgrade

External Post Tensioning

Encased in Concrete

PT Beam

Damaged

From Snow

Load

External Post Tensioning

Encased in Concrete

External Post Tensioning

Encased in Concrete

DUCON® Slurry-infiltrated Micro-Reinforced

Ultra High Performance Concrete

MicroMat®

Micro-Reinforcement

Tensile: 60 - 80 ksi

DUCON®

Self Consolidating Slurry

Compressive: ~ 20 ksi

DUCON®

Ductile Concrete

Compressive: ~ 22 ksi

Tensile: ~ 3 ksi

Shear: ~ 2 ksi

Bundled Wire Layers

Multiple layer mat

Wire Size: 0.04” to 0.06”

Wire Spacing: 0.3” to 1.0”

Wire Strength: 60ksi or 80ksi

(Plan View)

mesheswire

Micro-reinforcement mesh

Concrete Slurry Infiltration

15,000psi+

slurry

2 i

nc

he

s

Diameter

0.9 inch

10-12 MicroMat layers

per inch

Micro-reinforced Concrete Slurry

Bending Performance

Original Concept - Thin Load Bearing Elements

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

Surface Preparation

- Roughen surface to ¼” amplitude (CSP-7)

- No dowels required

Install Steel Mesh (specified layers)

Slurry Pumped into Forms

(Material Flow – Plexiglass Window)

Slurry Pumping

Cured and Finished Product

Test Beam

DUCON - Slab Overlay

(structural and/or finish upgrades)

• Crack sealing

• Crack control

• Water-tight

Precast Elements

Thin and strong

Column forms, walls

Strengthening – enlargement

Beams and slabs (flexure, shear)

Columns (axial, seismic)

Surface Repair

Crack sealing, crack control, water-tight

Industrial flooring

Blast Protection

Energy dissipation

Fragmentation and spall protection – “safety net”

Primary Applications - Review

Spall and Breach

RFC

36 inch

RFCBREACH

& SPALL

18 inch

SPALL

18 inch

0’

10’

20’Slab, Column Or Wall

Primary Damage

mode: Flexure

Effects:

Rotation

Cracking

Minimal Spalling

0ft 3ft 8ft 20ft

STAND

OFF

CHARGE

Stand Off & Perimeter Blast Threats

(>20’ standoff distance)

Typical Blast Pressure Range:

4 psi - 10 psi

0’

7.5’

15’Slab, Column Or Wall

0’ 3 20ft

MID

RANGE

CHARGE

Mid Range Blast Threat

8

Primary Damage

mode: Flexure

Secondary Damage

mode: Shear

Effects:

Some Spalling

Small Projectiles

No Breach

(>8’ and < 20’)

Typical

Blast Pressure:

10 psi - 20 psi

0’

6’

12’Slab, Column Or Wall

CLOSE

RANGE

CHARGE

0’ 3 20ft

Primary Damage mode:

Shear

Secondary Damage

Mode: Flexure

Significant Spalling

Large Projectiles

Possible Breach

Close Range Threat

8

(>3’ and < 8’)

Typical

Blast Pressure:

20 – 200 psi

0’

4’

8’

Primary damage mode:

Shear

Effects:

Breach (certain)

Shock wave penetrates

Heavy Spalling

Large projectiles

0’

Contact Detonation Blast Threat

Slab, Column Or Wall

3’

CONTACT

CHARGE

Typical

Blast Pressure:

200 psi – 100K psi

(< 3’)

Shear Strength Test

DUCON® Ultra High Performance Concrete

RFC

Rear Side

100 lb Close Range Detonation Testing

Protected Side

No SpallNo Breach

Attacked Side

Contact Detonation Test Results

Cast in Place

Walls

DUCON® INSITU SPALL LINERS (WALLS)

3”

Cast in Place

Walls

Cast in Place

Walls

THE PARKLAWN BUILDINGDepartment of Health and Human Services

PHASE 1

PHASE 2

PHASE 3

The Parklawn Building

1200 Columns, 21 Column Sizes, 8 Different Conditions

Column Blast Shields

Install wire mesh

Column Blast Shields

Form and pump cement

Column Blast Shields

Partial height column jacket Full height column jacket

DUCON - Precast Wall Panels

Blast Mitigation for Columns for Truck Sized Bomb at Curbside

No FRP

14”

14”

Blast Mitigation for Columns with FRP

No FRP

Blast Mitigation for Columns with FRP

With FRP

Overall Intent ???

“Design and implement structural solutions

based on our experience and technologies.”

Shaun Loeding, P.E.

Director - Strengthening Division

Concluding remarks – THANK YOU !

• Please visit www.structural.net and www.structuraltechnologies.com

• Technical design support

• Budgetary estimate support

• Repair and QA/QC specs

• Contracting services

• Technical “Lunch-Box” training seminars available:

- Strengthening - Corrosion Protection - Concrete Repair

- Building Envelope - Waterproofing - Force protection

• Current projects?

• Local contact: Shaun Loeding, P.E.

631-488-7421

sloeding@structural.net