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TRANSCRIPT
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
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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