advanced structural materials for concrete...
TRANSCRIPT
Advanced Structural Materials for Concrete Bridges
Tuesday, December 3, 20191:00-2:30 PM ET
TRANSPORTATION RESEARCH BOARD
The Transportation Research Board has met the standards and
requirements of the Registered Continuing Education Providers Program.
Credit earned on completion of this program will be reported to RCEP. A
certificate of completion will be issued to participants that have registered
and attended the entire session. As such, it does not include content that
may be deemed or construed to be an approval or endorsement by RCEP.
Purpose
To identify and compare several advanced performance structural materials that may be used on bridges.
Learning Objectives
At the end of this webinar, you will be able to:
• List four new advanced structural materials for concrete bridge applications
• Describe the benefits of each advanced structural material
• Describe the challenges of implementing these structural materials
PDH Certificate Information• This webinar is valued at 1.5 Professional Development
Hours (PDH)• Instructions on retrieving your certificate will be found in
your webinar reminder and follow-up emails• You must register and attend as an individual to receive a
PDH certificate• Certificates of Completion will be issued only to individuals
who register for and attend the entire webinar session –this includes Q&A
• TRB will report your hours within one week• Questions? Contact Reggie Gillum at [email protected]
Michigan Department of TransportationFRP prestressing codes and guidance
Matthew J. Chynoweth, P.E.Chief Bridge EngineerDirector, Bureau of Bridges and Structures
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Introduction of current needs in bridge durability & Advanced Structural Materials of interest
• Material Systems:• Prestressed Concrete using either CFRP & HSSS • Reinforced Concrete using FRP rebar (Glass & Basalt FRP)• Ultra-High Performance Concrete (UHPC)
• without reinforcing;• with traditional reinforcing and/or prestressing (carbon-steel)• with ASM reinforcing and/or prestressing (HSSS or FRP)
• Justification of higher initial cost from ASM’s• Durability Enhancement – potentially increased Service Life / significantly reduced Thru-life
Maintenance Repair & Rehabilitation (MRR);• Resilience – superior Mechanical Performance, Damage Tolerance for continued service,
increased Adaptability options (long-term widening, structure repurposing);• Sustainability – Reduced embodied energy, CO2 emissions using circular economy principals;• Life-Cycle Cost Analysis (LCC) - economic comparisons;• Life Cycle Analysis (LCA) - environmental comparisons
A recent TRB webinar covered the National AASHTO LRFD Guide Specifications:
TRB Webinar: Carbon Fiber-Reinforced Polymer Systems for Concrete Structures
http://www.trb.org/BridgesOtherStructures/Blurbs/179731.aspx
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Stages of prestressing force
𝑃𝑃𝑗𝑗: Initial jacking force
𝑃𝑃𝑝𝑝𝑝𝑝𝑝𝑝: Prestressing force immediately before transfer
𝑃𝑃𝑝𝑝𝑝𝑝𝑝𝑝 = 𝑃𝑃𝑗𝑗
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𝑃𝑃𝑖𝑖: Prestressing force immediately after transfer
𝑃𝑃𝑖𝑖 = 𝑃𝑃𝑝𝑝𝑝𝑝𝑝𝑝 𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸𝐸 𝐸𝐸𝑠𝑠𝑠𝑠𝑠𝐸𝐸𝑠𝑠𝑠𝑠𝐸𝐸𝑠𝑠𝑠𝑠 𝐸𝐸𝑠𝑠𝐸𝐸𝐸𝐸𝑠𝑠𝐸𝐸, 𝑓𝑓𝑝𝑝𝑝𝑝𝑝𝑝
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𝑓𝑓𝑝𝑝𝑝𝑝𝑝𝑝(𝑘𝑘𝐸𝐸𝐸𝐸) = 10.0𝑓𝑓𝑝𝑝𝑝𝑝𝑝𝑝𝐴𝐴𝑝𝑝𝑝𝑝𝐴𝐴𝑔𝑔
𝛾𝛾ℎ𝛾𝛾𝑠𝑠𝑝𝑝 + 12.0𝛾𝛾ℎ𝛾𝛾𝑠𝑠𝑝𝑝 + 𝑓𝑓𝑝𝑝𝑝𝑝
𝛾𝛾ℎ = 1.7 0.01H
𝛾𝛾𝑠𝑠𝑝𝑝 =5
(1 + 𝑓𝑓𝑐𝑐𝑖𝑖′ )
𝑃𝑃𝑒𝑒: Effective prestressing force after long-term losses
𝑃𝑃𝑒𝑒 = 𝑃𝑃𝑖𝑖 { 𝐶𝐶𝑠𝑠𝑠𝑠𝑠𝑠𝐶𝐶 + 𝐸𝐸𝑠𝑠𝑠𝐸𝐸𝑠𝑠𝑘𝑘𝐸𝐸𝑠𝑠𝑠𝑠 + 𝑠𝑠𝑠𝑠𝐸𝐸𝐸𝐸𝑟𝑟𝐸𝐸𝐸𝐸𝐸𝐸𝑠𝑠𝑠𝑠 𝐸𝐸𝑠𝑠𝐸𝐸𝐸𝐸, 𝑓𝑓𝑝𝑝𝑝𝑝𝑝𝑝} 𝑓𝑓𝑝𝑝𝑝𝑝𝑝𝑝
H: Humidity = 70
𝑓𝑓𝑝𝑝𝑝𝑝𝑝𝑝: stress in FRP immediately prior to transfer
𝑓𝑓𝑝𝑝𝑝𝑝
𝑓𝑓𝑝𝑝𝑝𝑝𝑝𝑝
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Check stresses @ service limit state
Prestressing force (𝑃𝑃𝑒𝑒)
Self-weight of the beam (or non-composite section) + Dead load + superimposed dead loads + Live loads
Concrete full strength (𝑓𝑓𝑐𝑐′)
𝜎𝜎𝑝𝑝𝑏𝑏𝑝𝑝 = −𝑃𝑃𝑒𝑒𝐴𝐴𝑛𝑛𝑛𝑛
𝑃𝑃𝑒𝑒.𝑒𝑒𝐼𝐼𝑛𝑛𝑛𝑛
𝑦𝑦𝑝𝑝 + 𝑀𝑀𝑛𝑛𝑛𝑛𝐼𝐼𝑛𝑛𝑛𝑛
𝑦𝑦𝑝𝑝 + 𝑀𝑀𝐷𝐷𝑛𝑛𝐼𝐼𝑛𝑛𝑦𝑦𝑝𝑝 + 0.8 𝑀𝑀𝐿𝐿𝐿𝐿
𝐼𝐼𝑛𝑛𝑦𝑦𝑝𝑝 (Service III)
𝜎𝜎𝑝𝑝𝑏𝑏𝑝𝑝 = −𝑃𝑃𝑒𝑒𝐴𝐴𝑛𝑛𝑛𝑛
+ 𝑃𝑃𝑒𝑒.𝑒𝑒𝐼𝐼𝑛𝑛𝑛𝑛
𝑦𝑦𝑝𝑝𝑀𝑀𝑛𝑛𝑛𝑛𝐼𝐼𝑛𝑛𝑛𝑛
𝑦𝑦𝑝𝑝𝑀𝑀𝐷𝐷𝑛𝑛𝐼𝐼𝑛𝑛𝑦𝑦𝑝𝑝
𝑀𝑀𝐿𝐿𝐿𝐿𝐼𝐼𝑛𝑛𝑦𝑦𝑝𝑝 (Service I) 𝑠𝑠𝐸𝐸
𝐸𝐸
Critical section@ mid-span
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MDOT guide:
No tension is allowed in pre-compressed
tensile zone of CFRP prestressed beams
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Most common Less common
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𝜌𝜌𝑝𝑝𝑒𝑒 =𝐴𝐴𝑝𝑝𝑒𝑒𝑏𝑏.𝑑𝑑1
Reinforcementratio Depth of stress block Section design Failure mode
𝜌𝜌𝑝𝑝𝑒𝑒 < 𝜌𝜌𝑝𝑝_𝑝𝑝𝑏𝑏𝑏𝑏 𝛽𝛽1 𝐸𝐸 < 𝑑𝑑 Rectangular Tension𝜌𝜌𝑝𝑝𝑒𝑒 > 𝜌𝜌𝑝𝑝_𝑝𝑝𝑏𝑏𝑏𝑏 𝛽𝛽1 𝐸𝐸 < 𝑑𝑑 Rectangular Compression𝜌𝜌𝑝𝑝𝑒𝑒 < 𝜌𝜌𝑝𝑝_𝑝𝑝𝑏𝑏𝑏𝑏 𝑑𝑑 < 𝛽𝛽1 𝐸𝐸 < 𝑑𝑑 + 𝑝𝑝 Flanged Tension𝜌𝜌𝑝𝑝𝑒𝑒 > 𝜌𝜌𝑝𝑝_𝑝𝑝𝑏𝑏𝑏𝑏 𝑑𝑑 < 𝛽𝛽1 𝐸𝐸 < 𝑑𝑑 + 𝑝𝑝 Flanged Compression
𝜌𝜌𝑝𝑝𝑒𝑒 < 𝜌𝜌𝑝𝑝_𝑝𝑝𝑏𝑏𝑏𝑏 𝛽𝛽1 𝐸𝐸 > 𝑑𝑑 + 𝑝𝑝Double Flanged Tension
𝜌𝜌𝑝𝑝𝑒𝑒 > 𝜌𝜌𝑝𝑝_𝑝𝑝𝑏𝑏𝑏𝑏 𝛽𝛽1 𝐸𝐸 > 𝑑𝑑 + 𝑝𝑝Double Flanged Compression
𝑑𝑑: Depth of deck slab 𝑝𝑝: Depth of top flange of beam
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b
bw
hf
d1
c
d1-c
𝜀𝜀1𝜀𝜀2
𝜀𝜀3𝜀𝜀4
𝜀𝜀𝑖𝑖
𝜀𝜀𝑐𝑐
di-c
𝜀𝜀𝑖𝑖 = 𝜀𝜀1𝑑𝑑𝑖𝑖 𝐸𝐸𝑑𝑑1 𝐸𝐸
𝜀𝜀𝑖𝑖 = Strain in CFRP reinforcement at layer 𝐸𝐸, not including the effective prestressing strain 𝜀𝜀𝑝𝑝𝑒𝑒
N.A.
Strain Distribution
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b
bw
hf
d1
c
d1-c
𝑇𝑇1𝑇𝑇2
𝑇𝑇3𝑇𝑇4
𝑃𝑃𝑝𝑝𝑝𝑝𝑒𝑒𝑠𝑠𝑝𝑝𝑝𝑝𝑒𝑒𝑠𝑠𝑠𝑠
𝜀𝜀𝑐𝑐
di-c
𝑇𝑇𝑖𝑖 = 𝜀𝜀𝑖𝑖 .𝑠𝑠𝑖𝑖 .𝐸𝐸𝑝𝑝.𝐸𝐸𝑝𝑝
𝑇𝑇𝑖𝑖 = Force in CFRP reinforcement at layer 𝐸𝐸, not including the effective prestressing force 𝑃𝑃𝑒𝑒
N.A.
Forces in section
𝑇𝑇𝑖𝑖
𝐹𝐹𝑐𝑐
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𝐴𝐴𝑝𝑝𝑒𝑒 = �𝑖𝑖=1
𝑖𝑖=𝑚𝑚
𝐴𝐴𝑖𝑖_𝑒𝑒𝑒𝑒𝑒𝑒 𝜌𝜌𝑝𝑝𝑒𝑒 =𝐴𝐴𝑝𝑝𝑒𝑒𝑏𝑏.𝑑𝑑1
Calculate the neutral axis depth for a balanced section, 𝐸𝐸𝑝𝑝𝑏𝑏𝑏𝑏𝐸𝐸𝑝𝑝𝑏𝑏𝑏𝑏𝑑𝑑1
=𝜀𝜀𝑐𝑐𝑐𝑐
𝜀𝜀𝑐𝑐𝑐𝑐 + (𝜀𝜀𝑔𝑔𝑐𝑐 𝜀𝜀𝑝𝑝𝑒𝑒)
(rectangular sections)
𝜌𝜌𝑝𝑝𝑒𝑒 < 𝜌𝜌𝑝𝑝𝑏𝑏𝑏𝑏𝜌𝜌𝑝𝑝𝑒𝑒 > 𝜌𝜌𝑝𝑝𝑏𝑏𝑏𝑏
Tension failure
Compression failure
𝜌𝜌𝑝𝑝𝑏𝑏𝑏𝑏 =0.85𝑓𝑓𝑐𝑐′𝛽𝛽1𝐸𝐸𝑝𝑝𝑏𝑏𝑏𝑏𝑏𝑏𝑤𝑤 + 0.85𝑓𝑓𝑐𝑐′ 𝑝𝑝 𝑏𝑏 𝑏𝑏𝑤𝑤 𝑃𝑃𝑒𝑒
𝐸𝐸𝑝𝑝 𝜀𝜀𝑔𝑔𝑐𝑐 𝜀𝜀𝑝𝑝𝑒𝑒 𝑏𝑏𝑑𝑑1(Flanged sections)
𝜌𝜌𝑝𝑝𝑏𝑏𝑏𝑏 =0.85𝑓𝑓𝑐𝑐′𝛽𝛽1𝐸𝐸𝑝𝑝𝑏𝑏𝑏𝑏𝑏𝑏 𝑃𝑃𝑒𝑒𝐸𝐸𝑝𝑝 𝜀𝜀𝑔𝑔𝑐𝑐 𝜀𝜀𝑝𝑝𝑒𝑒 𝑏𝑏𝑑𝑑1
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Calculate the depth of the N.A., 𝐸𝐸
Calculate the flexural strain in different reinforcement layers & strain in concrete
𝜀𝜀𝑖𝑖 = 𝜀𝜀1𝑑𝑑𝑖𝑖 𝐸𝐸𝑑𝑑1 𝐸𝐸
𝜀𝜀𝑐𝑐 = 𝜀𝜀1𝑐𝑐
𝑑𝑑1−𝑐𝑐< 𝜖𝜖𝑐𝑐𝑐𝑐
Where, 𝜀𝜀1 = 𝜀𝜀𝑔𝑔𝑐𝑐 𝜀𝜀𝑝𝑝𝑒𝑒
𝐸𝐸 =𝐸𝐸𝑝𝑝 .𝐴𝐴𝑝𝑝𝑒𝑒 . (𝜀𝜀𝑔𝑔𝑐𝑐 𝜀𝜀𝑝𝑝𝑒𝑒) + 𝑃𝑃𝑒𝑒
0.85 𝑓𝑓𝑐𝑐′ 𝛽𝛽1 𝑏𝑏
For a rectangular section
𝐸𝐸 =𝐸𝐸𝑝𝑝 .𝐴𝐴𝑝𝑝𝑒𝑒 . (𝜀𝜀𝑔𝑔𝑐𝑐 𝜀𝜀𝑝𝑝𝑒𝑒) + 𝑃𝑃𝑒𝑒 0.85𝑓𝑓𝑐𝑐′ 𝑝𝑝 𝑏𝑏 𝑏𝑏𝑤𝑤
0.85 𝑓𝑓𝑐𝑐′ 𝛽𝛽1 𝑏𝑏𝑤𝑤
For a flanged section
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Calculate the nominal moment capacity of the section, 𝑀𝑀𝑛𝑛
For a flanged section
𝑀𝑀𝑛𝑛 = �𝑖𝑖=1
𝑖𝑖=𝑚𝑚
𝐸𝐸𝑝𝑝 𝑠𝑠𝑖𝑖 𝐸𝐸𝑝𝑝 𝜀𝜀𝑖𝑖 𝑑𝑑𝑖𝑖𝛽𝛽1𝐸𝐸
2+ 𝑃𝑃𝑒𝑒 𝑑𝑑𝑝𝑝
𝛽𝛽1𝐸𝐸2
+0.85 𝑓𝑓𝑐𝑐′ 𝑝𝑝 𝑏𝑏 𝑏𝑏𝑤𝑤𝛽𝛽1𝐸𝐸
2𝑝𝑝
2
For a rectangular section, use the same eqn. with 𝑏𝑏𝑤𝑤 = 𝑏𝑏
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M-102 over Plum Creek: Design
Twin 75’ long single span structures, using 33” x 48” side by side box beams prestressed with CFCC
M-102 over Plum Creek: Design
80.03
21
Determination of number of the theoretical number of CFCC strands based on calculation of excess tension in bottom flange based on Service III limit state:
Allow for 0 tension in bottom flange at service, as opposed to allowable
M-102 over Plum Creek: Design
CFCC strand data based on testing:
GUTS = 60.70 kipsAstrand = 0.179 in2
f’pu = 339 ksi – calculated ultimate tensile strengthCE = 0.90 – environmental factor per ACI 440.1R-06fpu = 305 ksi – design ultimate tensile strengthEps = 21,000 ksi
M-102 over Plum Creek: Design
Assume strand eccentricity based on strand center of gravity is between two rows of strands, and equal number of strands in each row:
Strand stress limit prior to transfer:
1
60.0
M-102 over Plum Creek: Design
Assume 25% losses, and calculate the number of strands to start, then refine design based on service and strength limit state checks:
75.0
M-102 over Plum Creek: Design
Need to develop jacking forces to stay below creep-rupture curve, while efficiently providing force to offset excess tension due to applied loads
M-102 over Plum Creek: Fabrication
15.2 mm strand reels – 1043 m each
M-102 over Plum Creek: Fabrication
Coupled strands, pull steel strands
M-102 over Plum Creek: Fabrication
Monitoring force in strands via load cells
M-102 over Plum Creek: Fabrication
Strand stressing complete, pouring concrete
M-102 over Plum Creek: Fabrication
Reinforcement complete, finishing concrete pour
M-102 over Plum Creek: Fabrication
Completed beam – no release stress cracking
M-102 over Plum Creek: Deck casting
M-102 over Plum Creek: Deck casting
M-102 over Plum Creek: Completed structures
MDOT/Lawrence Technological University MathCAD Templates:
https://mdotjboss.state.mi.us/SpecProv/trainingmaterials.htm
High-Strength Stainless Steel (HSSS)Prestressed Concrete (PC)
Will Potter
Florida Department of Transportation
Material Development
• Research• Georgia Tech• University of South Florida
• Materials Evaluated• Austenite - 316, 304 and XM-29• Duplex 2101, 2205 and 2304, • Martenistic 17-7
• Current Production Material • Duplex 2205
Moser et al, 2012
Duplex 2205Provides highest strength and best corrosion resistance among those evaluated
Duplex 2205Mechanical Properties
Duplex 2205 Alloy ASTM A416 PC Strand CFRP
Diameters (in) 0.375 to 0.7* 0.375 to 0.7 0.375 to 0.7**
Tensile Strength (ksi) 240 to 250 250, 270, 300+ 300+
Elongation @ UTS
Duplex 2205 –Material Testing
• Mechanical Properties w/ Wedge Chucks
• Initial Stress Limitations (constructability and design)• 60-65% fpu (conventional steel 75% fpu)
Al-Kaimakchi, 2019
Duplex 2205Material Testing
• Transfer and Development Length Testing• AASHTO equations are conservative
• Bond Strength• ASTM A1081
• Prestress Losses• AASHTO equations are adequate
17.8 kip – average 15.8 kip – minimum
ASTM A1081
Al-Kaimakchi, 2019
Paul, A. 2017 and Al-kaimakchi, 2019
Constructability• Conventional stressing methods
• Conventional detensioning methods
• Limit initial stress
Brown, 2018 Brown, 2018
HSSS-PC Piling
Initial Implementation
Coastal StatesGeorgiaFloridaVirginia
Louisiana
Moser, 2012
St. George Island, FL
HSSS-PC Piling
Projects
Brown, 2018
Sprinkel, 2018 Paul, A, 2015
Cornelius, 2019
Standardization in Florida- Piling -
• Specifications• Design Guidance • Design Standards
FDOT Structures Design Manual
FDOT Material Specifications
Piling Design Standards
HSSS-PC Flexural Members
• NO official flexural design guidance, currently• Limited research evaluating flexural design with HSSS• Ohio DOT – adjacent box beam brdige
️️
️️
Al-Kaimakchi, 2019
Flexural Design Considerations
• Conventional steel strands• Yielding of strands followed by
crushing of concrete ( cu = 0.003)
• Stainless steel strands• Crushing of concrete
• cu = 0.003, pu < 0.014
• Balanced Condition • cu = 0.003, pu = 0.014
• Strand rupture• cu < 0.003, pu = 0.014
• Strength Resistance Factors?
Strain Compatibility Design Approach
0 0.002 0.004 0.006 0.008 0.01 0.012 0.014 0.016 0.018 0.02
Strain (in./in.)
0
50
100
150
200
250
Stre
ss (k
si)
Stainless steel strands
Prestress Strainafter losses
Available Strain
Initial Strain0.65 fpu
Efforts to Develop Overall Design Guidance
• Georgia Tech – complete• Primary evaluation of piling with limited
evaluation of flexural design
• FAMU/FSU – active research• Investigating flexural behavior• Developing predictive analytical models• Developing design guidance
• NCHRP – upcoming research
• Planned Guidance Options (based on above research)• AASHTO Guide Specification for Bridge Design
with Stainless Steel Strand• Incorporate into AASHTO Bridge Design
Specification
References
• Al-kaimakchi, A. 2019. Flexural Beam Testing Program for Stainless Steel Strands. PCI Committee Days Presentation.
• Brown, K. 2018. Production of Prestressed Concrete Piles Using Stainless Steel. ASPIRE Magazine. P30-32.
• Cornelius, J. 2019. Prestressing Steel – New and Existing Products Overview. PCI Committee Days Presentation.
• Moser et al. 2012. Durability of Precast Prestressed Concrete Piles in Marine Environment, Part 2, Volume 2: Stainless Steel Prestressing Strand & Wire. GDOT Project No. 10-26, Task Order No. 02-78.
• Paul, A. L. F. Kahn, and K. E. Kurtis. 2015. Corrosion-Free Precast Prestressed Concrete Piles Made with Stainless Steel Reinforcement: Construction, Test and Evaluation. Report no. FHWA-GA-15-1134. Atlanta: Georgia Institute of Technology.
• Paul, A. L. B. Gleich, L. F. Kahn. 2017. Structural Performance of Prestressed Concrete Bridge Piles Using Duplex Stainless Steel Strands. ASCE Journal of Structural Engineering.
• Paul, A. L. B. Gleich, L. F. Kahn. 2017. Transfer and development length of high-strength duplex stainless steel strand in prestressed concrete piles. PCI Journal May-June 2017.
1
Advanced Structural Materials for Concrete Bridges
1. Introduction of current needs in bridge durability & Advanced Structural Materials of interest (Matthew Chynoweth)
2. CFRP-PC Design guidance & standards documents (Matthew Chynoweth)
3. HSSS-PC Design guidance & standards documents(Will Potter)
4. UHPC Design guidance & standards documents(Kyle Riding)
5. FRP-RC Design guidance & standards documents (Antonio Nanni)
6. Life-Cycle Cost analysis strategies(Antonio Nanni)
7. Moderated Question & Answer(Steven Nolan)
1
2
Ultra-High Performance Concrete
“UHPC is limited to concrete that has a minimum specified compressive strength of 22,000 psi (150 MPa) with specified durability tensile ductility and toughness requirements; fibers are generally included to achieve specified requirements. UHPC typically exhibits elastic-plastic or strain-hardening characteristics under uniaxial tension and has a very low permeability due to its dense and discontinuous pore structure.” -ACI 239
Precast/ Prestressed Concrete Institute (PCI) is going to define UHPC as concrete with 18 ksi compressive strength
3
Map of Known UHPC Bridge Projects
https://usdot.maps.arcgis.com/apps/webappviewer/index.html?id=41929767ce164eba934d70883d775582
4
Benefits of UHPC
Tensile performance can allow you to reduce amount of steel reinforcementCan optimize geometry for lighter member to reduce shipping costs and crane sizeReduce cover dimensions?Dense and discontinuous microstructure can give very high durability – alternative to stainless steel and FRP reinforcement
5
UHPC Application Example: Connections & Repair
Mixing – high energy needed Placing Curing(long mixing time or high shear mixer needed)
6
UHPC Application Example: Piles
7
UHPC Application Example: Potential Pile Shapes
Hollow PilesH-Piles
Geometry optimized to reduce weight and material use, increase skin friction
Tested in 2008 – see Voort, Suleiman, and Sritharan, Design and Performance Verification of Ultra-High Performance Concrete Piles for Deep Foundations
Maher Tadros, PCI Presentation 2018
8
UHPC Application Example: Piles
Picture courtesy of Miles Zeeman
9
UHPC Pile Driving Test100 ft. Test pile driven in Leesburg, FL
10
UHPC Application Example: Segmental Construction
Pedestrian Bridge in Medellin, Colombia Built in 2017 First Bridge in Colombia made from UHPCSaved 30% compared to alternative steel designCurrently constructing 2nd bridgeAlso adapting UHPC for pavement overlays
17400 psi (120 MPa) concrete
11
UHPC Application Example: Segmental Construction
361 ft long bridge4 spansMain Span is 141 ft. long29 precast segments, 10 tons each24 post-tension cables
Nunez, Patino, Arango, and Echeverri, “REVIEW ON FIRST STRUCTURAL APPLICATIONS OF UHPC IN COLOMBIA,” Second International Interactive Symposium on UHPC, Albany, NY., June 2-5, 2019, Paper 118.
12
UHPC Application Example: Hybrid Girders
Figure courtesy of Eduardo Torres and Trey Hamilton
UHPC
Self-Consolidating Concrete
UHPC used on end-regions to reduce end-cracking, and potentially allow for longer spans
13
Fresh Property Testing: Flow TestingASTM C1856 – use ASTM C1437 flow table and cone, without base and without performing dropsMeasure the flow 120 ± 5 s after lifting mold to nearest 1 mm (ave. of 2 measurements)
Recommendation: 8 to 14 in. flow diameter (Wille 2011)
14
Stress-Strain Relationships
fc
c,y c,u
Compressive Stress-Strain Behavior
E
fct
cc pu
Tensile Stress-Strain Behavior
E
Based on ACI 239R18 Based on FHWA-HIF-13-032
15
Constitutive Relationships and Ultimate Limit State for UHPC with Macro-Reinforcement
Concrete
Steel
M
Beam FBD Strain
--
+
s
Figures based on ACI 239R18
-u,t
u,c
s
c
Ft,c
Ft,s
Fc,c
Stress from Stress-Strain Relationship Forces
16
24-hour 4-day 7-day 28-dayBefore traffic opening
Alabama 14 (97) 21 (145) 14 (97)Delaware 14 (97)Idaho 14 (97) 20, 25 (138, 172)*Iowa 10 (69) 15 (103)Maine 21 (145)
Michigan 15 (103)
Nebraska 21 (145)New Jersey 5.7 (39) 11.6 (80) 14.5 (100)New Mexico 14 (97) 21 (145)New York 12 (83) 21 (145)Texas 14 (97) 21 (145)West Virginia 12 (83) 15 (103)Ontario 11.6 (80) 18.9 (130)
Canada17.4, 21.7 (120, 150)†
France18,850-36,300 (130-250) +
Switzerland 17.4 (120)
Compressive Strength Requirement
Values given in psi (MPa)
ASTM C1856 modifies ASTM C39 to use 3 × 6 in. cylinders
17
Tensile strength Flexural strengthFlexural Tough.
ksi (MPa) ksi (MPa) ASTM C1018
Alabama AASHTO T 198, 1.0 (6.9) splitting
Delaware
Idaho ASTM C293, 2 (14)IowaMichiganNew Jersey I30New MexicoNew York I30Texas I30
Ontario ASTM C1609, 2.2 (15)
Canada 0.58, 0.73 (4, 5), direct tension
0.58, 0.73 (4, 5) with inverse analysis
Tensile Strength Requirement
18
Qualification Tensile Testing Direct Tension Test ASTM C1609 modified by ASTM C1856
Friction in support conditions can increase flexural capacity 30-60% (Wille and MontesinosWille, K., & Parra-Montesinos, G. (2012). Effect of beam size, casting method, and support conditions on flexural behaviour of UHPFRC. ACI Materials Journal, 109(3), 379–388.)
19
Direct Tension Test Direct Tension Test Samples After Testing
-1500
-1000
-500
0
500
1000
1500
0 0.005 0.01 0.015 0.02
Stre
ss (p
si)
Strain
0
90
180
270
Average
side
2 × 2 × 17 in. samples
20
Durability RequirementsProperty
Chloride Ion Penetrability Shrinkage
Chloride Ion Penetrability Scaling
Resistance
Freeze-Thaw Abrasion Resistance Alkali-Silica
Reactivity(coulombs) (microstrain) (oz/ft3) (RDM %) (oz.)
Test Method ASTM C1202/ AASHTO T 277 ASTM C157 AASHTO T259 ASTM C672
ASTM C666A, 600 cycles
ASTM C944, 2x weight ASTM C1260
Alabama T160 < 0.026
Delaware <0.07, ½ in. (13mm) depth y < 3 > 95% 0.08%, test at 28
days
Idaho < 250 < 765, initial reading after set
< 0.07, 1/4th in. (6mm) depth y < 3 > 96% < 0.025, ground
surface
ASTM C1567, < 0.10%, test at 28 days
New Jersey <1.0, ½ in. (13mm) depth y < 3 > 96% < 0.03 Innocuous, test at
28 days
New Mexico <0.059, ½ in. (13mm) depth No scaling > 99%, 300 cycles < 0.026 < 0.10%,
Innocuous
New York reading after set< 0.07, 1/5th in. (5mm) depth y < 3 > 96% < 0.025, ground
surfaceInnocuous, test at 28 days
Texas y < 3 > 96%, 300 cycles < 0.1%
Canada <500, <300, <100
X (different method)
CSA A23.2-22C 0.4,0.2,0.1 kg/m2 <5, <1, <0.5 g
21
Design-Related Properties
Creep coefficient (ACI 239R18)0.31 (steam cured)0.8 (non-heat cured)
Negligible shrinkage after heat curingElastic Modulus: 6000 to 7200 ksi (function of fibers and fc)
https://www.fhwa.dot.gov/publications/lists/022.cfm
FHWA has published many reports on UHPC:
22
Options for UHPCPre-blended, prebagged, proprietary UHPC
Comes with support from manufacturerProven resultsHigh cost ($2000-3000/yd3)
Make-your-own UHPC with local materialsHigh knowledge base needed (can hire consultants to help)Can get 18-22ksi with local materials without too much difficultyCan save 30-74%1 from cost of preblended materialsGuidelines/ papers on how to make UHPC with local materials
Development of ultra-high performance concrete with locally available materials https://doi.org/10.1016/j.conbuildmat.2016.12.040Development of Cost-Effective Ultra-High Performance Concrete (UHPC) for Colorado’s Sustainable Infrastructure 1Ultra-high performance concrete with compressive strength exceeding 150 MPa (22 ksi): a simpler way DOI: 10.14359/51664215Design and per Design and performance of cost-eff formance of cost-effective ultra-high per a-high performance formanceconcrete for prefabricated elements https://scholarsmine.mst.edu/cgi/viewcontent.cgi?article=3587&context=doctoral_dissertations
Biggest cost is fibersMade in USA steel fibers available
1 Kim, “Development of Cost-Effective Ultra-High Performance Concrete (UHPC) for Colorado’s Sustainable Infrastructure,” Final Report, CDOT-2018-15, 2018.
23
Implementation ChallengesHigh amount of QC needed, especially for fiber distribution, orientation, and plant-ready tensile testExperienced contractors/ precasters needed
Placement direction impacts fiber alignment & tensile strength
Mixing time 15-30 minutes, much shorter with high shear mixerWorking time is short – once you stop agitating it, can lose workability rapidly and form “elephant skin”New UHPC does not bond well to old UHPCStructural design equations made for conventional concrete can work, but don’t fully take advantage of UHPC (ie. Creep, development length, etc.)Most durability testing done on UHPC with fc’ >150 ksiSpecifications need to catch up with material
Example of specifications that need updating: ACI 318-19 Air Entrainment Requirements
Nominal Max. Agg. Size (in.)
Target Air Content, F1 (%)
Target AirContent, F2 & F3 (%)
3/8 6.0 7.5
1/2 5.5 7.0
3/4 5.0 6.0
1 4.5 6.0
1-1/2 4.5 5.5
2 4.0 5.0
3 3.5 4.5
FRP-RC Design Guidance & Standards Documents
+ Life-Cycle Cost analysis strategies
TRB Webinar Date: December 3, 1:00-2:30pm ESTModerator: Steven Nolan
Presenter: Antonio NanniUniversity of [email protected]
2
Advanced Structural Materials for Concrete Bridges
1. Introduction of current needs in bridge durability & materials of interest• CFRP & HSSS prestressing; FRP rebar;
UHPC
2. CFRP-PC Design guidance & standards documents (Matthew Chynoweth)• Costs and Design tools• Implementation challenges
3. HSSS-PC Design guidance & standards documents (Will Potter)• Costs and Design tools• Implementation challenges
4. UHPC Design guidance & standards documents (Kyle Riding)• Costs and Design tools• Implementation challenges
5. FRP-RC Design guidance & standards documents (Antonio Nanni)• Costs and Design tools• Implementation challenges
6. Life-Cycle Cost analysis strategies (Antonio Nanni)• ASM comparisons and synergies• Future enhancements or needs
7. Moderated Question & Answer(Steven Nolan)
2
3
OF Contents
· Problem Statement· FRP Materials and Design Properties· Guides, Standards and Specs· Where to use GFRP· What do we still need· Field Applications in Florida· Cost Justification (Service Life, LCC & LCA)· Conclusions
3
4SERVICE LIFE GREATLY REDUCED BY CORROSION
Problem Statement• Cause of failure for structures
exposed to aggressive environments is often corrosion of steel reinforcement
• Chlorides from de-icing salts or seawater penetrate concrete and reach steelü via cracks ü via concrete porosity
• Corrosion is accelerated by carbonation that lowers concrete pH
4
5
Traditional corrosion mitigation efforts center on keeping chlorides from getting to reinforcing steel or simply delaying the diffusion time
State-of-Practice
• Admixtures• Increase Concrete Cover• Alter Concrete Mix• Membranes & Overlays• Epoxy-Coated, Galvanized
or Stainless Steel
5DELAYING SYMPTOMS RATHER THAN CURING DISEASE
Photo: Courtesy of TxDOT
6
OF Contents
· Problem Statement· FRP Materials and Design Properties· Guides, Standards and Specs· Where to use GFRP· What do we still need· Field Applications in Florida· Cost Justification (Service Life, LCC & LCA)· Conclusions
6
FRP Bars, Strands and Grids Typically produced by the Pultrusion process
8
Production Process (Pultrusion)
.
9
Factors Affecting Material Characteristics
• Fiber volume• Type of fibers• Type of resin• Fiber orientation• QC during manufacturing• Rate of curing• Void content• Service temperature
10
Tensile Behavior• Tensile properties obtained from bar manufacturer• Manufactures must report a guaranteed tensile strength f*fu, as
mean tensile strength minus three standard deviations
• Similarly, a guaranteed rupture strain
11
Critical Design Provisions
Flexural Resistance
Shear Resistance
GFRP Design Tensile Strength
Ultimate capacity provisions:
11
12
Critical Design Provisions
GFRP Creep Rupture Strength
GFRP Fatigue Strength
Spacing for Crack Control
12
Fatigue and serviceability provisions:
13
13
Evaluation of Durability: Selected Bridges• Eleven bridges located across the United States• Each bridge contains GFRP bars in deck or other location
and has been in service for at least 15 years
• Gills Creek Bridge (VA)• O’Fallon Park Bridge (CO)• Salem Ave Bridge (OH)• Bettendorf Bridge (IA)• Cuyahoga County Bridge (OH)• McKinleyville Bridge (WV)• Thayer Road Bridge (IN)• Roger’s Creek Bridge (KY)• Sierrita de la Cruz Creek Bridge (TX) • Walker Box Culvert Bridge (MO)• Southview Bridge (MO)
14
.
Sierrita de la Cruz Creek Bridge, Texas • Location: 25 miles northwest Amarillo, TX• Agency: Texas DOT• Year Built: 2000• Geometry: 7 spans, 553 ft. long, 45 ft. wide• Bridge Type: GFRP deck top mat, concrete deck on PC girders
Selected Bridges (Example)
15
GFRP Tests: Modified Tensile Strength Test• Extracted and virgin coupons were tested in tension• Virgin new generation full-size bars were also tested in tension
• The results of virgin full-size bars from tensile tests performed in 2000 were used for comparison
• A correlation was calculated to determine the tensile strength of the extracted bars
Sample Full-sizeStrength, psi
CouponStrength, psi
Coupon to Full-size
Pristine 119,318 96,997 18.71%
Extracted Bars 113,840a 90,110 20.84%
Difference due to degradation % 2.13%
Note: a = Tested in 2000
16
OF Contents
· Problem Statement· FRP Materials and Design Properties· Guides, Standards and Specs
ACI and ASTMAASHTO, Florida DOT, and Texas DOT
· Where to use GFRP· What do we still need· Field Applications in Florida· Cost Justification (Service Life, LCC & LCA)· Conclusions
16
17
How To Specify for Building Structures
SPECIFYING AND CONSTRUCTING WITH GFRP BARS17
18
.
Update on AASHTO Activities related to FRP bars for Bridge Structures
19
.
Harmonize with national (ACI, ASTM and AASHTO-BDS) andinternational (CSA) specifications.
• Ease design/deployment• Ease certification• Enlarge market
Update existing provisions to reflect better materials andmanufacturing, and new research findings.
• Make design more efficient
Expand provisions to include all members of a bridge.
• Allow the design of a bridge entirely GFRP-RC
Approach and Relevance of expanded 2018 AASHTO Guide Spec.
20
Comparison of Critical Design ParametersAASHTO 2nd 2018
AASHTO 1st 2009
ACI 440 Code 2021?
ACI 440.1R2015
ffu* 99.9 99.9 99.9 99.9 Strength percentileC 0.75 0.65 0.65 0.65 Res. fact. concr. failureT 0.55 0.55 0.55 0.55 Res. fact. FRP failureS 0.75 0.75 0.75 0.75 Res. fact. shear failure
CE 0.70 0.70 0.90 0.70 Environm. reductionCC 0.30 0.20 0.30 0.20 Creep rupt. reductionCf 0.25 0.20 n/a 0.20 Fatigue reductionCb 0.83 0.70 0.70 to 0.83 0.70 Bond reductionw 0.027 0.0200 0.027 0.020 to 0.027 Crack width limit [in.]
cc,stirrup 1.5 1.5 2.0 2.0(1) Clear cover [in.]cc,slab 1.0 0.75 to 2.0 0.75 to 2.0 0.75 to 2.0(1) Clear cover [in.]shear 0.004 0.004 0.004 0.004 Strain limit in shear
(1) ACI 440.5-08 Table 3.1To be finalized
20
21
• Mandatory Specs• Uniform Approval Processes
- Manufacturer Approval vs. Product Approval• Design Tools
Design Guidance & Tools: Florida DOT
https://www.fdot.gov/structures/innovation/FRP.shtm
22
• Uniform Approval Processes- Manufacturer Approval & Certification vs. Product Approval
https://mac.fdot.gov/smoreports
Design Guidance & Tools: Florida DOT
23
• Need for Accessible & Reliable Design Tools- Commercial vs. Agency/Institution based design programs
https://www.fdot.gov/structures/proglib.shtm
** Available on request
CFRP-PC (w/ GFRP-RC Shear) Beta version **
GFRP-RC Alpha version **
GFRP-RC included (3b)
GFRP-RC in development !
Design Guidance & Tools: Florida DOT
24
Example of other DOT Activities related to FRP bars.
Texas DOT:Update of bridge deck design using GFRP Top Mat in accordance with 2018 AASHTO Guide Spec
25
Texas DOT: top-mat GFRP reinforcement
26
Ohio DOT: Bridge deck GFRP reinforcement
Maine DOT: Bridge deck GFRP reinforcement
Other Active DOTs in the use of FRP bars
27
OF Contents
· Problem Statement· FRP Materials and Design Properties· Guides, Standards and Specs· Where to use GFRP· What do we still need· Field Applications in Florida· Cost Justification (Service Life, LCC & LCA)· Conclusions
28
• Concrete members susceptible to steel corrosion by chlorides or
• low concrete pH• Concrete members requiring non-
ferrous reinforcement due to electro-magnetic considerations
• Need of thermal non-conductivity
Where Should FRP be Used?
ALTERNATIVE TO EPOXY, GALVANIZED AND STAINLESS STEEL REBAR
29
• Seawalls, Piles and Piers• Marine Structures• Bridge Decks • Traffic Railings• Approach Slabs• Barrier / Retaining Walls• Culverts• Sewage System Tunneling• Parking Garages
Infrastructure Applications
30
OF Contents
· Problem Statement· FRP Materials and Design Properties· Guides, Standards and Specs· Where to use GFRP· What do we still need· Field Applications in Florida· Cost Justification (Service Life, LCC & LCA)· Conclusions
30
31
What do we still need? Refinement of conservative Design Limits
2021?
To be finalized
32
What do we still need? Gaps in Design & Deployment
• Connections (post-installed & couplers)
• Fatigue limits• Elastic modulus• Bent bars• Scalability of production
1700+ adhesive-dowelled anchors (HRB 2019)
33
OF Contents
· Problem Statement· FRP Materials and Design Properties· Guides, Standards and Specs· Where to use GFRP· What do we still need· Field Applications in Florida· Cost Justification (Service Life, LCC & LCA)· Conclusions
33
34
Project Examples: FAST FACTS
Fast-Facts: https://www.fdot.gov/structures/innovation/FRP.shtm#link9
35
Homosassa, FL 2017-19 (GFRP-RC & CFRP-PC) Five-span vehicular bridge
July 16, 2019
Fast-Facts: https://fdotwww.blob.core.windows.net/sitefinity/docs/default-source/structures/innovation/fastfacts/fastfacts-430021-1.pdf
Project Examples: HALLS RIVER BRIDGE
36
Six-man crew can assemble complete bent cap GFRP rebar cage in 4.5 hours
Project Examples: HALLS RIVER BRIDGE
37
University of Miami – Completed 2016:
Project Examples: INNOVATION PEDESTRIAN BRIDGE
Fast-Facts: https://fdotwww.blob.core.windows.net/sitefinity/docs/default-source/structures/innovation/fastfacts/fastfacts-innovationbridge-um.pdf
Elevation view of Innovation Bridge with BFRP reinforcement in the auger-cast-piles, bent-caps, double-tee stems and flanges, deck overlay and curbs
38
CIP continuous flat-slab bridge under construction 2019:
Project Examples: NE 23RD AVE overIBIS WATERWAY
Fast-Facts: https://fdotwww.blob.core.windows.net/sitefinity/docs/default-source/structures/innovation/fastfacts/fastfacts-434359-1.pdf?sfvrsn=175168c2_2
39
2016 conditions prior to 5,000’ of Secant-Pile Wall construction (2019)
Remains left after Hurricane Matthew destructive forces resulted in “wash-out” and destruction of the essential State Road A1A, which is an Evacuation Route
Project Examples: SR-A1A SECANT-PILESEAWALL
40
GFRP-CAGES AT WORK
Seawall’s auger-cast concrete secant-piles are 36-inch (910 mm) diameter. Primary piles are 36-feet (11 m) in length and are reinforced with 25 ~ #8 GFRP bars.
Fast-Facts: https://fdotwww.blob.core.windows.net/sitefinity/docs/default-source/structures/innovation/fastfacts-440557-7.pdf?sfvrsn=73e5bc6a_2
Project Examples: SR-A1A SECANT-PILESEAWALL
OF Contents
· Problem Statement· FRP Materials and Design Properties· Guides, Standards and Specs· Where to use GFRP· What do we still need· Field Applications in Florida· Cost Justification (Service Life, LCC & LCA)· Conclusions
41
LCC & LCA also can show the sustainable (economic and environmental) advantage of FRP-RC structures in the coastal environment:
Cost Justification (Service Life, LCC & LCA)
Example: LCC & LCA Comparison of Carbon Steel-RC/PC versus FRP-RC/PC (various effective discount rate), adapted from Cadenazzi et al. 2019 42
CS-RC/PC Bridge Replacement
FRP-RC/PC Bridge Replacement
43
Younis et al., 2018: Carbon-Steel vs. SSR vs. GFRP rebar
https://doi.org/10.1016/j.conbuildmat.2018.04.183
(Baseline scenario with discount rate = 0.7%)
RC1 = Traditional concrete mix with carbon-(black) steel rebar;RC2 = Traditional concrete mix with SS rebar;RC3 = Concrete with seawater & RCA with GFRP rebar.
Cost Justification (Service Life, LCC & LCA)
Performance as a function of maintenance:
CS-RC/PC alternative SS or FRP-RC/PC alternativesCadenazzi, T., Dotelli, G., Rossini, M., Nolan, S., and A. Nanni. (2019). Cost and Environmental Analyses of Reinforcement Alternatives for a Concrete Bridge. Structure and Infrastructure Engineering 44
Cost Justification (Service Life, LCC & LCA)
CE effect
www.ASCEgrandchallenge.com“Reduce the life cycle cost of infrastructure by 50% by 2025 and foster the optimization of infrastructure investments for society”
Rebar Example Cost Comparisons:
• Cost information based of Contractor bid prices• Price of epoxy reinforcing @ $1.00/LB
Anthony Wayne Trail over NSRR Cost Per Square Foot of Deck
Epoxy Coated Reinforcing $8.052/SF
GFRP Reinforcing (GFRP 1st Edition) $9.587/SF
GFRP Reinforcing (GFRP 2nd Edition) $8.736/SF
45
Cost Justification (Service Life, LCC & LCA)
• Cost information is from Engineer’s estimate• Price of epoxy reinforcing @ $1.15/LB• Recent increase in steel cost (15%-20% Increase)
• Result in more competitive costs
Industrial Drive over the Maumee River
Cost Per Square Foot of Deck
Epoxy Coated Reinforcing $11.805/SF
GFRP Reinforcing $10.609/SF
46
Rebar Example Cost Comparisons:
Cost Justification (Service Life, LCC & LCA)
OF Contents
· Problem Statement· FRP Materials and Design Properties· Guides, Standards and Specs· Where to use GFRP· What do we still need· Cost Justification (Service Life, LCC & LCA)· Field Applications in Florida· Conclusions
47
Conclusions
• Complete set of guides, test methods and standards available for GFRP bars
• Many structures successfully built with GFRP bars and performing well• Non-proprietary solutions, traditional supply chain acquisition &
installation available• Extended service life of GFRP reinforced concrete ensured • Current practices adopted for corrosion protection are unnecessary with
GFRP reinforcement• New frontiers to be explored to improve resilience and sustainability
48
Thank you for your attention!
The End
49
Today’s Speakers• Steven Nolan, Florida DOT,
[email protected]• Matt Chynoweth, Michigan DOT,
[email protected]• William Potter, Florida DOT,
[email protected]• Kyle Riding, University of Florida,
[email protected]• Tony Nanni, University of Miami,
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