Presentation on theme: "Joining Issues in the Implementation of Fiber Reinforced Polymer (FRP) Composites in the Civil Infrastructure Jack Lesko Macromolecules and Interfaces."— Presentation transcript:
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 21 st 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
High Performance Materials Status
Barriers to Routine use of HPM 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
Composites: Directional Stiffness & Strength Strength Stiffness L / T 40:1 25:1 T -Transverse L - Longitudinal Failure mode Longitudinal Transverse
Bolted Joints & Orthotropy FRP material and orientation influence failure mode and load
Unidirectional FRP vs Steel/Concrete Stress (ksi) Strain (%) Carbon/Epoxy E=20-50 Msi 0.06 lbs./in 3 Glass/Epoxy E=7-10 Msi 0.07 lbs./in 3 Steel E=30 Msi 0.28 lbs./in 3 Can we design with a brittle material like FRP?
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) Load Resistance Risk How does one incorporate acceptable design approaches for DOT’s?
Fiber Reinforced Polymer (FRP) Composite Structures & Adhesive Systems
Martin Marietta Materials 10m (33’) Span 7.3m (24’) Width 0.84m (2’-9”) Depth 10 kg (22 kip) Weight HS20-44 Smith Road Bridge, Butler County, OH
Three deck and superstructure elements make up the FRP bridge
Butler County Bridge Monitoring Bridge Deck External FO gages Internal FO gages Bondline FO gages 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) Wave length sensitivity based on grating size I( ) I( )
Field Bond Line -Moisture Absorption Bond Line Adhesive - Coclesive 1090 (2 Part Epoxy) Fiber-Optic Sensors in Bond Line: “Sapphire Fiber Sensors”
Fiber Optic Sensors: Sapphire Fiber Data Wavelength (cm-1) Absorbance July 8th 1997 Nov 17th, 1997 Jan 28th, 1998 Aug 27th, 1998 Infrared spectroscopy of bondline cure
Fourier Transform Infrared (FTIR)Spectra of Derakane Aged in water at 65°C until saturation. 1 mol H 2 0 : 4 mol OH “OH” Stretch Region Unaged Aged Absorbance Wavenumbers (cm -1 )
Composite Pultrusion Process Constant cross section High volume production
Martin Marietta Materials, Inc Decks installed or successful bid IA, NY, PA, MD, OH, CA Alliance with
Application of the joining adhesive Top surface completion of field joints Martin Marietta Materials, Inc
Creative Pultruion Wickwire Run, Aug ’ Span 21.7’ Width HS25 Laurel Lick, May ’ Span 16’ Width HS20-44
Bonding of SuperDeck Adhesive bonging area a source of fatigue and strength concerns
Hardcore Composites, LLC Magazine Ditch Bridge, DE Cecil County Bridge, MD 9+ decks or bridges in place: DE, NY, PA, OH, MD Market focus: short span, rapid installation, weight savings 5% of bridge rehab market & Zoltek
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 Cut-away of splice plate to transfer shear and moment. Splice plate Structural adhesive The Salem Ave. project in Ohio is presently experiencing problems due to failure of joining technologies used and field installed
Plan View Section A-A 15 ft. 10 ft. Excavated panel of PCC pavement in weigh station off- ramp Adjustable/Simulated bridge girders 5’ x 15’ Composite Deck Section Girder centerline Troutville Weigh Station Deck Test Bed Facility installed November 1999 Traffic Steel access panels
Troutville Weigh Station Interstate 81, Troutville, VA 5’ x 15’-3” Composite Deck Section Characterized traffic loads (actual/severe service environment) Routine inspection capability designed into system Flexible foundation design to allow for future experimental bridge decks Laboratory inspection & evaluation Adjustable/Simulated bridge girders Excavated panel of PCC pavement in weigh station off- ramp
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 support beam flange wearing course steel sleeve Deck #1 Deck #2 Deck #3 “Hook bolt to tie rod”
Deck #2 – Service Damage Wear surface cracking corresponding to tube widths Adhesive delamination & tube failure at connection
Where to Next for Adhesives in an FRP Infrastructure?
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