impressions of design & calculation

Composites in Infrastructure: impressions of design & calculation Rotterdam, May, 2015 ir. Jan Peeters Director R&D / co-founder FiberCore FiberCore Europe, Rotterdam peeters@fibercore-europe.com

Composites? Fiber reinforced plastics (FRP) Fibers glass, carbon, aramide Resins polyester, vinylester, epoxy

Production processes for FRP

Raw material comparison

Specific properties E/(ρ*g) Mild steel (0,5;2,75) σ/(ρ*g)

Carbon fibers

Composites: stiffness dominated designs 600 MPa Stress composite 0/90ᵒ, 75/25% Assume: sandwich with composite skins Same EI wall thickness 6,64 t UC on strength: 0,1 ; safety margin 10 Wall thickness 6,64 t 360 MPa steel Depth H Wall thickness 6,64 t Width B Assume: sandwich with steel skins Designed for strength: UC = 1 Bending stiffness EI Wall thickness t Use in bridge 34 GPa 210 GPa Depth H Wall thickness t Width B 0 0,2% 2% Strain

Example bridge design Assume linear elasticity Assume beam behaviour Assume three-point-bending Design for stiffness (usability limit state)

Max. deflection of the beam In steel: u max 5 384 ql L4 EI F 2 L 2 3 EI 3 In composite: 5 384 ql L4 u max EI 1 8 ql L2 GA F 2 L 2 3 EI 3 1 4 F L GA in which EI = bending stiffness, GA = shear stiffness

CUR96 directive S f In which: R d and with: S = load on structure R d R.d R.k?.M?.c?.f R d = design resistance of the structure R k = characteristic resistance γ M = partial material factor η c = conversion factor γ f = load factor R k c M the design resi the characteris the partial mate the conversion the load factor

CUR96 directive M Rd m In which partial factors for uncertainty: γ Rd = in resistance model and geometry γ m = caused by the nature of materials and production methods used

CUR96 directive c ct cv ck cf In which conversion factors: η ct η cv η ck η cf = effects of temperature = effect of moisture = creep = fatigue

CUR96 directive Combined: S f c M R k or: S f Rd ct cv m ck cf R k

Example With, e.g.: γ f = load factor = 1.0 (usability limit state) γ Rd = model & geometry = 1.0 γ m = materials & production = 1.2 (RTM, post cured) η ct = effects of temperature = 1.0 (if T T g - 40 C) η cv = effect of moisture = 1.0 (mostly dry) η ck = creep = 0.8 (non crimp, 100 yrs) η cf = fatigue = 0.9 Follows: S 1.64 R k

Think composites

Composite material properties First: design the required material Step 1: the properties of the unidirectional layer Variables: Fibre properties Resin properties Fibre volume fraction

Composite material properties Step 2: the off-axis properties of the unidirectional layer

Composite material properties Step 3: stack these properties to obtain the properties of the laminate Use laminate theory rules of mixtures

Geometrical properties Bending stiffness EI Shear stiffness GA EI GA E i I i i G i A i i

MathCad tool

Important design considerations, especially for deck structures FiberCore Europe: Do not use composite materials in infrastructure, unless these materials and structures are robust and damage tolerant

Crack tip in composites A B C Fibre Reinforced Plastics Inhomogenic, layered material Fibres act as crack arrestors Vulnerable to cracking between fibre layers ( interlaminar cracking or delamination )

A lot can and does go wrong

What is required for reliable use of FRP in Infra, are structures which after a serious impact load show no debonding and no cracking or delamination which may cause catastrophic failure, not directly and not after 10, 50 or even 100 years of intensive use; have been proven with certified long term tests to be damage tolerant; therefor have no potentially critical resin or adhesive dominated fracture paths; preferably are monolithic, encompassing all structural parts, enabling robust joints to, and proper cooperation with, surrounding steel and concrete structuresl have continuous reinforcing fibers which guarantee a robust connection between top skin core bottom skin..

There is a robust solution The only technology to comply with the requirements formulated in the previous sheets, proven and patented worldwide.

The essence of InfraCore Inside a brief introduction

Assume a steel beam: - two flanges, connected by - a web

Steel beam: Two flanges, connected by a web

Steel box beam: Flanges, connected by webs Flanges interconnected

Steel box plate: Flanges, connected by webs Flanges interconnected

Steel beam: Two flanges, connected by a web

z y x Glass Fibre Fabric beam: Two flanges, connected by a web One layer of ±45ᵒ fabric

z y x Glass Fibre Fabric beam: Two flanges, connected by a web One layer of ±45ᵒ fabric + one layer of 0ᵒ fabric on flanges

z y x Glass Fibre Fabric beam: Two flanges, connected by a web Flanges 0ᵒ/ ±45ᵒ fabric, web ±45ᵒ fabric

z y x Carbon/Glass Fibre Fabric beam: Two flanges, connected by a web Flanges 0ᵒ carbon/ ±45ᵒ glass fabric, web ±45ᵒ glass fabric

z y x Glass Fibre Fabric beam: Two flanges, connected by a web Flanges 0ᵒ/ ±45ᵒ fabric, web ±45ᵒ fabric + one layer op 90ᵒ fabric

z y x Glass Fibre Fabric beam: Two flanges, connected by a web Flanges 0ᵒ/ ±45ᵒ fabric, web 90ᵒ/±45ᵒ fabric

Glass Fibre Fabric box beam: Flanges, connected by webs Flanges 0ᵒ/ ±45ᵒ fabric, webs 90ᵒ/±45ᵒ fabric

Glass Fibre Fabric box plate: Flanges, connected by webs Flanges 0ᵒ/ ±45ᵒ fabric, web 90ᵒ/±45ᵒ fabric

Steel beam Loaded in three-point bending

Steel beam Loaded in three-point bending Shear load distribution on cross section

Glass Fibre Fabric beam Loaded in three-point bending

Glass Fibre Fabric beam Loaded in three-point bending Shear load distribution on cross section Continuous transfer of shear loads

A B C Fibre Reinforced Plastics Inhomogenic, layered material Fibres act as crack arrestors Vulnerable to cracking between fibre layers ( interlaminar cracking )

Glass Fibre Reinforced Plastic Multi-beam Box plate Beams are self-contained Little shear transfer between beams Impact damage may occur: local delamination

Glass Fibre Reinforced Plastic Multi-beam Box / Sandwich plate Interlaminar cracking is inconsequential No skin-core debonding, no damage growth

Focus on beam directly under impact A crack in flange-web zone may occur

Focus on beam directly under impact Crack will not grow, constricted by fibres

Focus on beam directly under impact Beam can carry load despite crack Much residual surface to carry shear loads Stable situation

Glass Fibre Reinforced Plastic Multi-beam Box / Sandwich plate Interlaminar cracking is inconsequential No skin-core debondng EXTREMELY ROBUST

Glass Fibre Fabric beam: Add shear webs perpendicular to main webs Made of ±45ᵒ fabric in box configuration

Glass Fibre Fabric box beam: Flanges, connected by webs Flanges 0ᵒ/ ±45ᵒ fabric, webs 90ᵒ/±45ᵒ fabric, cross-webs ±45ᵒ fabric

GRP pultruded beam: Achilles heel Supported in three-point bending Impaced by hard object flange-web crack initiation

GRP pultruded beam: Achilles heel Loaded in three-point bending Unarrested crack growth catastrophic failure

Classic sandwich: Achilles Heel Two skins bonded on a core Impaced by hard object skin-core debonding

Classic sandwich: Achilles Heel Two skins bonded on a core Crack growth caused by rolling loads

Classic sandwich: Achilles Heel Two skins bonded on a core Catastrophic failure, due to unrestricted weak resin dominated fracture path

Multi beam plate: Achilles Heel Many box beams bonded together Impaced by hard object crack in and between webs

Multi beam plate: Achilles Heel Many box beams bonded together Crack growth caused by rolling loads

Multi beam plate: Achilles Heel Many box beams bonded together Failure, due to unrestricted weak resin dominated fracture path

Multi beam plate: Achilles Heel Many box beams bonded together, with additional deck layers Impaced by hard object two weak resin dominated fracture paths

Glass Fibre Fabric box beam: Extreme robustness

Important design considerations, especially for deck structures Eurocode 0 (EN-1990), Section 2.1 Basic Requirements (4)P A structure shall be designed and executed in such a way that it will not be damaged by events such as: explosion impact, and the consequences of human errors, to an extent disproportionate to the original cause.

Important design considerations, especially for deck structures Eurocode 0 (EN-1990), Section 2.1 Basic Requirements (5)P Potential damage shall be avoided or limited by appropriate choice of one or more of the following: avoiding, eliminating or reducing the hazards to which the structure can be subjected; selecting a structural form which has low sensitivity to the hazards considered; selecting a structural form and design that can survive adequately the accidental removal of an individual member or a limited part of the structure, or the occurrence of acceptable localized damage; avoiding as far as possible structural system that can collapse without warning; tying the structural members together.

Important design considerations, especially for deck structures Eurocode 0 (EN-1990), Section 2.1 Basic Requirements (6) The basic requirements should be met: by the choice of suitable materials, by appropriate design and detailing, and by specifying control procedures for design, production, execution, and use relevant to the particular project.

What is InfraCore Inside... From classic sandwich to InfraCore...

Thank you! Ir. J.H.A. Peeters www.fibercore-europe.com peeters@fibercore-europe.com

Benefits of InfraCore Inside Fail safe, durable multiple load paths in bridges, typically a factor of 10 safety tremendous heat and fire resistance high energy absorption when crushed Sustainable low carbon footprint low energy consumption less environmental pollution Light weight high strength at relatively low weight easy to transport easy to install simple lightweight foundations relocateable floating on water no technical maintenance required integrally re-usable recyclable at end-of-life Low maintenance excellent adhesion of wear surfaces corrosion resistant UV resistant pest resistant graffiti resistant Appealing appearance slender, curved all colors possible textured surfaces possible Fast production a standard bridge can be built in 1 week High value cost competitive (out of pocket costs) lower total cost of ownership

Awards Tech-25 company FEM Business & Finance Innovatietraject InfraTech Belgie 2010 Building Holland Award 2010 (nominated) PRIMA Ondernemen Award 2011 (nominated) AVK Umweltpreis 2011 WNF Clean Tech Star 2013 (nominated) InfraTech Halftime Award 2013 Waterinnovatieprijs 2014