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Joining Issues in the Implementation of Fiber Reinforced Polymer (FRP) Composites in the Civil Infrastructure. Jack Lesko Macromolecules and Interfaces Institute Materials Response Group Department of Engineering Science & Mechanics. How are we going to fix this?. Statistics on Bridges.
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Joining Issues in the Implementation of Fiber Reinforced Polymer (FRP) Composites in the Civil Infrastructure Jack Lesko Macromolecules and Interfaces Institute Materials Response Group Department of Engineering Science & Mechanics
How are we going to fix this?
Statistics on Bridges • 600,000 Bridges in the US • 4-10% in a state of advanced decay • 1/3 “structurally deficient" or "functionally obsolete" • 132,000 deficiencies attributed to decks decay • Cost of rehabilitation$50 billion by the year 2000 or $167 billion for bridges & highways • Yet, only $5 billion is annually budgeted
What’s being done? • Transportation Equity Act for the 21st Century (TEA21) two central goals: A.) Reduced user delays B.) Deployment of advanced materials (Innovative Bridge & Construction Program) • Other Efforts • Civil Engineer Research Foundation • NIST • Composites Institute - CFA/MDA • AASHTO • ACI
Administrative Fragmentation of the materials suppliers, manufacturers, structural engineers & construction industry Lack of interdisciplinary training for design engineers Cost (first vs. life cycle) Limited commercial capital for development of new systems Incremental - piecemeal approach to FRP bridge design Technical Lack of DOT design specifications Performance vs. Material specification Lack of sufficient long-term data and experience Plethora of new materials, additives & combinations One-for-One material substitution Connection technologies Barriers to Routine use of HPM
Composites: Directional Stiffness & Strength Transverse Longitudinal T-Transverse L- Longitudinal Strength Stiffness Failure mode L / T 40:1 25:1
Orthotropy Uni-directional Cross-ply Angle-ply Quasi-Isotropic
Bolted Joints & Orthotropy FRP material and orientation influence failure mode and load
Unidirectional FRP vs Steel/Concrete Carbon/Epoxy E=20-50 Msi r=0.06lbs./in3 Can we design with a brittle material like FRP? 400 300 200 100 0 Glass/Epoxy E=7-10 Msi r=0.07lbs./in3 Stress (ksi) Steel E=30 Msi r=0.28lbs./in3 0 5 10 20 30 Strain (%)
FRP Bridge Decks • Rapid rehabilitation technology • Raise live load rating by reducing dead load Concerns • Connections remain a problem (girder-to-deck & guardrail-to-deck) • Internal bonding • Stiffness criteria for design (L/?) • Wearing surface
Deck Connections How do we efficiently, durably and quickly make inter panel and deck to girder connections?
Guradrails for FRP Decks Guardrails are attached using either top or side mounting
Load Resistance Factor Design (LRFD) Resistance Load Risk How does one incorporate acceptable design approaches for DOT’s?
Fiber Reinforced Polymer (FRP) Composite Structures & Adhesive Systems
Smith Road Bridge, Butler County, OH • 10m (33’) Span • 7.3m (24’) Width • 0.84m (2’-9”) Depth • 10 kg (22 kip) Weight • HS20-44 Martin Marietta Materials
Smith Road Bridge, Butler County, OH Three deck and superstructure elements make up the FRP bridge
Bondline FO gages Bridge Deck Internal FO gages External FO gages Butler County Bridge Monitoring • Intrinsic Fabry-Perot Interferometer (IFPI) used as a strain sensor • “Sapphire” chemical sensors for monitoring adhesive cure and moisture uptake (Foster-Miller)
Intrinsic Fabry-Perot Interferometer (IFPI) I(l) l I(l) l li Wave length sensitivity based on grating size
Field Bond Line -Moisture Absorption Bond Line Adhesive - Coclesive 1090 (2 Part Epoxy) Fiber-Optic Sensors in Bond Line: “Sapphire Fiber Sensors”
Absorbance Aug 27th, 1998 Jan 28th, 1998 Nov 17th, 1997 July 8th 1997 3600 3400 3200 3000 2800 Wavelength (cm-1) Fiber Optic Sensors:Sapphire Fiber Data Infrared spectroscopy of bondline cure
1 mol H 0 : 4 mol OH 2 Fourier Transform Infrared (FTIR)Spectra of Derakane 441-400 Aged in water at 65°C until saturation. 1.15 “OH” Stretch Region 1.10 1.05 1.00 0.95 Aged 0.90 Absorbance 0.85 0.80 0.75 0.70 Unaged 0.65 0.60 0.55 4000 3800 3600 3400 3200 2800 2600 2400 Wavenumbers (cm-1)
Composite Pultrusion Process • Constant cross section • High volume production
Martin Marietta Materials, Inc Alliance with Decks installed or successful bid IA, NY, PA, MD, OH, CA
Martin Marietta Materials, Inc Top surface completion of field joints Application of the joining adhesive
Creative Pultruion • Wickwire Run, Aug. 1997 • 30’ Span • 21.7’ Width • HS25 • Laurel Lick, May 1997 • 20’ Span • 16’ Width • HS20-44
Bonding of SuperDeck Adhesive bonging area a source of fatigue and strength concerns
Hardcore Composites, LLC & Zoltek Market focus: short span, rapid installation, weight savings 5% of bridge rehab market Cecil County Bridge, MD 9+ decks or bridges in place: DE, NY, PA, OH, MD Magazine Ditch Bridge, DE
Resin Infusion • SCRIMP™ process • Net shape parts • Custom tooling • Typically room temperature cure VARTM = Vacuum assisted resin transfer molding
Wilson Run Bridge, Valley Forge National Historic Park, PA • One of the state's oldest wrought iron truss bridges • 2- Hour installation Composites
Hardcore Deck Installation Structural adhesive Splice plate Cut-away of splice plate to transfer shear and moment. The Salem Ave. project in Ohio is presently experiencing problems due to failure of joining technologies used and field installed
Troutville Weigh Station Deck Test Bed Section A-A 10 ft. 5’ x 15’ Composite Deck Section Excavated panel of PCC pavement in weigh station off- ramp Adjustable/Simulated bridge girders Traffic 15 ft. Section A-A Steel access panels Plan View Girder centerline Facility installed November 1999
FRP Deck In-Service Troutville, VA Weigh Station Interstate 81 5,000 vehicles/day Installed Nov. 1999
Location of Damage to Deck #2 Foundation girder connections loosen Deck-to-girder connections loosen May 2000
Deck Connections wearing course steel sleeve support beam flange Deck #1 Deck #3 Deck #2 “Hook bolt to tie rod”
Deck #2 – Service Damage Wear surface cracking corresponding to tube widths Adhesive delamination & tube failure at connection
FRP Strengthening • External strengthening • Hoop reinforcement
Snap Together Connections? Courtesy of Brandt Goldsworthy & Associates
Comments: FRP Bridges • New structural forms appropriate for FRP ($, manufacturability, constructability) • Vertical integration of industry, design, and construction • Emphasis on joining & connections • Must beat other/conventional designs on first and or installed cost • Interdisciplinary effort - education
What’s Needed? • Integration of the adhesive folks with the Civil Infrastructure folks • Design and manufacturing approach for “off-the-shelf” deck system • Connection designs for rehabilitation situations • Design approaches to field installation of adhesive bonds • Design approach including reliability and warrantee assessment • Crash tested guard-rails for FRP decks and girder system bridges Near-Term Long-Term