towards a structural eurocode for frp structures: … · construction of a pedestrian and cycle...

TOWARDS A STRUCTURAL EUROCODE FOR FRP STRUCTURES: THE ROLE OF CEN/TC 250

L. Ascione

Dept. of Civil Engineering University of Salerno

Italy [email protected]

Stuttgart - November 7, 2018

9th International Conference on Fibre-Reinforced Polymer Composites in Civil EngineeringCICE 2018 – Paris – July 17-19 2

Outline of the presentation

1) Spread of the FRP structures in Europe: current state of the normative

1) Programming Mandate M/466 EN of EC to CEN/TC 250

2) What CEN/TC 250 has already done

3) Next steps

4) Conclusions


• Over the past twenty years, several innovative solutionsconfirmed the efficiency of the FRP composite structures,both within and outside Europe.

• The following slides show the spread of such structures inEurope.

FRP = Fibre Reinforced Polymer

Spread of FRP structures in Europe: DENMARK

Kolding, 1997. Construction of a pedestrian and cyclebridge from 100% pultruded GFRP profiles. The bridgeis 40m long and 3.2m wide. Its total weight is 120kN.The load capacity is of 5 kN/m2. The bridge wasinspected after 15 years service life and no damage

was found.

Copenhagen, 2008. Renovation of a sewage plantwith 1200 m2 pultruded GFRP coverings. The sewageplant is one of the biggest in Northern Europe andchose GFRP due to high durability requirements.

Karrebæksminde, 2011. Renovation of a basculeroadbridge where a pultruded GFRP deck wasinstalled on the old steel structure and a pedestrianand cycle bridge from 100% pultruded GFRP profilewas hung on the side to increase capacity.

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Spread of FRP structures in Europe: FRANCE

Joué les Tours. Solar charging station (SUDI™).Structure made from more than 80% of its weight incomposite (GFRP specific pultruded profiles and lowpressure molding parts). It supports 40 m2 of solarpanel.

Plessis Robinson. Helipad made with pultruded GFRPprofiles. A very efficient solution in terms of fireprotection, weight and quick installation.

Ephemeral cathedral of Creteil, 2014. Realization of aGFRP gridshell, made with pultruded tubes. Gridshellsoffer an important freedom of shape for the designer.The covered surface is 350 m2. 1775m of pultrudedtubes were used. The weight of the structure is 50N/m2.

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Spread of FRP structures in Europe: GERMANY

Hamm Uentrop, 2005. Construction of a 100% GFRPcooling tower as a beam-column system made frommore than 100t of pultruded structural profiles.

Friedberg Bridge, 2008. Motorway bridge underconstruction. The bridge, 27.0 m long and 5.0 m wide,consists of two steel beams covered by an innovativemulti-cell platform made of FBD 600 GRP profiles. Theprecast composite structural profiles were glued in-situonto the two steel beams.

Reinbek, Hamburg, 2009. Construction of a pedestrianbridge (Holländerbrücke). The bridge was made ofsteel beams and a GFRP pultruded deck. 100 m longand 3.5 m wide, it crosses the busy Hamburgerstraße.The modules of the bridge were built in a factory andthen transported by road to Reinbek where they wereplaced in position on the foundations.

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Spread of FRP structures in Europe: ICELAND

Hellisheidi, 2008. Construction of a 100% GFRP cooling tower as a beam-columnsystem made from more than 1000kN of pultruded structural profiles.

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Spread of FRP structures in Europe: ITALY

Archaeological area of Pitigliano, Grosseto 2004.Construction of a pedestrian bridge. Span 27.0m. GFRPpultruded profiles.

S. Maria Paganica Church, L’Aquila, 2010. Replacingthe roof of the church damaged by the earthquake ofApril 2009. GFRP pultruded members.

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Spread of FRP structures in Europe: Netherlands

Spieringsluis, Werkendam 2000. First FRP lock-gate inThe Netherlands, installed in Werkendam. Total width ofthe lock is 6 m, dimensions of each panel: width 3.5 m,height 6.5 m.

Floriadebrug, Venlo, 2012. Construction of a bicycle/pedestrian bridge with steel beams covered with aGFRP pultruded deck (BIJL plank 500 mm x 55 mm). Thebridge is 127.5 m long and 6 m wide and has beendesigned to carry vehicles up to 12 t weight.

Slender canopy with dimensions 43 m x 12 m (columnevery 10 m). Installed at the DSM Chemelot Campus inGeleen. 2009.

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Spread of FRP structures in Europe: Portugal

S. Mateus Bridge, Viseu, 2013. Pedestrian hybrid footbridge with a span of 13.3 m and 2 m ofwidth. Made of two steel girders bonded to a multi-cellular GFRP pultruded deck with panel-to-panel snap-fit connections.

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Spread of whole FRP structures in Europe: Russia

P. Vernadskogo subway station, Moscow, 2008. Archedwalkway realized with FRP profiles moulded by infusion.The bridge is the first one made of composite moulded byvacuum infusion. This technology offers the possibility ofeliminating the processes of assembly and decreases themanpower costs. Length: 22.6 m; width: 2.8 m; weight:55kN.

Salavat, 2007. Construction of a 100% GFRP cooling toweras a beam-column system made from more than 100t ofpultruded structural profiles.

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Spread of whole FRP structures in Europe: United Kinkdom

Golf Club in Aberfeldy (Scozia, 1992). Construction of apedestrian bridge. The length of the cable-stayed bridge is113 m long and has a main span of 63 m. The two piers andthe deck are made with GFRP, while the stays are made ofaramid fibre cables. The only parts that are not in compositeare the foundations, that are made of reinforced concrete,and the steel connection between the stays and thepedestrian walkway.

Motorway M6, Lancashire, 2006. Construction of a roadbridge over a motorway. The bridge is 52 m long and hasbeen designed to carry vehicles up to 400 KN weight. GFRPpultruded profiles FBD 600 ASSET.

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Spread of whole FRP structures in Europe: Switzerland

Münchensteinerstrasse, Basilea, 1999. Eyecatcherbuilding made of GFRP pultruded beam. The buildingconsists of 5 floors with a total of 15 m height; thesurface is 120 m2.

Novartis Campus Entrance Building, 2006 LightweightGFRP cell-core sandwich roof on load-bearing glass

envelop. Dimensions 21.6 m x 18.5 m.

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Current state of the normative

• Several Countries have contributed to the development of currently available guidelines,among which it may be appropriate to mention the following ones:

- EUROCOMP Structural Design of Polymer Composites (Design Code and Handbook, Finland,France, Sweden, UK, 1996);

- CUR 96 Fibre Reinforced Polymers in Civil Load Bearing Structures (Dutch Recommendation,2003);

- BD90/05 Design of FRP Bridges and Highway Structures (The Highways Agency, ScottishExecutive, Welsh Assembly Government, the Department for Regional Development NorthernIreland, May 2005);

- DIBt – Medienliste 40 für Behälter, Auffangvorrichtungen und Rohre aus Kunststoff, Berlin(Germany, May 2005);

- CNR-DT 205/2007 Guide for the Design and Construction of Structures made of Pultruded FRPelements (Italian National Research Council, October 2008);

- ACMA Pre–Standard for Load and Resistance Factor Design of Pultruded Fiber PolymerStructures (American Composites Manufacturer Association, November 2010);

- DIN 13121 Structural Polymer Components for Building and Construction (Germany, August2010);

- BÜVTragende Kunststoff Bauteile im Bauwesen [TKB] – Richtlinie für Entwurf, Bemessung undKonstruktion (Germany, 2010);

- CIRIA C779 publication for FRP Bridges - Guidance for Designers (UK, January 2018).

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Programming Mandate M/466 EN

• In May 2010, the European Commission-DG Enterprise and Industry issued theProgramming Mandate M/466 EN to CEN concerning the future work on theStructural Eurocodes. The interface with CEN has been the Technical Committee250 (CEN/TC250), in charge of drawing up the structural Eurocodes.

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• M/466 requested CEN to provide a programme for standardisation covering:

Development of new standards or new parts of existing standards, e.g. a newconstruction material and corresponding design methods or a newcalculation procedure;

Incorporation of new performance requirements and design methods toachieve further harmonisation of the implementation of the existingstandards.


• The works of the future generation of Eurocodes has to be carried out inseveral steps:

Step 1: Preparation and publication of a “Science and Policy Report”, subjectto agreement of CEN/TC250.

Step 2: After agreement of CEN/TC250, preparation and publication of CENTechnical Specifications (TS, previously known as ENV).

Step 3: After a period for trial use and commenting, CEN/TC250 will decidewhether the CEN Technical Specifications should be converted intoEurocode Parts.

• The end of the program has been scheduled by 2022.

• Within this Mandate, CEN/TC250 took the initiative to prepare a documentaddressing the purpose and justification for new European technical rules andassociated standards for the design and verification of composite structuresrealized with FRPs.

• CEN/TC250 formed a CEN Working Group WG4 to develop the work item.


• WG4 ended Step 1:

After about three years of activity and many meetings, WG4 drew up a proposal ofScientific and Technical Report (2016), whose title is Prospect for new guidance in designof FRP. It has been published by JRC.

From January 2016 to July 2016, the Report was subjected to public inquiry by theNational Standardizations Bodies of EU.

At the end of the inquiry, the Report was revised and resubmitted to CEN/TC 250, which,in July 2017, took the decision to start the adaptation into a CEN Technical Specification(Step 2). The revised version of the Prospect has been published by EuCIA.


• Step 2 just started

The Technical Specification will apply to the design of constructions realizedwith Fibre Reinforced Polymers (FRP). It will comply with the principles andrequirements for the safety and serviceability of structures as given in EN1990-Basis of structural design. The operational rules for the basis ofdesign, supplementary provisions for determination of action effects,robustness requirement and guidance for material-oriented design of FRPconstructions will be clearly given.

In order to achieve this goal, a project team of six members has beenappointed by CEN/TC 250 to help WG4 on the road to a structural Eurocode(Step 3). These members were selected by public tender.

The activities of Step 2 started at the end of July 2018.


• MAIN FEATURES OF THE PROSPECT

The topics taken into account address the FRP parts with afibre volume fraction of at least 15%, i.e. the ratio of fibrevolume to total volume.

The FRP composite has to be made up of glass fibres (E-glass fibres, R-glass fibres), carbon fibres of type HS, IM orHM and aramid fibres with a thermoset matrix ofunsaturated polyester, vinylester and epoxy resins.

The Prospect applies to FRP structures made of:- beams - laminated plates and shells- sandwich panels.

It does not include:- structures in which micro-cracks are not permissible

- reinforcing rods, cables or external reinforcement to existing structures using FRP.

The structural elements taken into account are realized by means of the main manufacturingprocesses as prepregging, pultrusion, compression moulding, resin transfer moulding,filament winding and hand lay-up.


Preface

Chapter 1 General

Chapter 2 Basis of Design (Partial Factors Method)

Chapter 3 Materials

Chapter4 Durability (UV Radiation; Temperature; Humidity; Static Charge; Fire)

Chapter 5 Basis of Structural Design (Modeling of FRP; Behaviour in the case of Fire; Designassisted by Testing)

Chapter 6 Ultimate Limit States (Profiles; Plates and Shells; Sandwich Panels)

Chapter 7 Serviceability Limit States (Deformations; Vibration and Comfort; Damage)

Chapter 8 Connections (Bolted and Adhesive Joints)

Chapter 9 Production, Realization, Management and Maintenance

Annex A About the conversion factor for creep effects

Annex B Indicative values of Fibres, Resins, Play and Laminate Properties

Annex C Elastic Buckling of Columns with Double Symmetric Profiles and Angle, Cruciforman T Profiles

Annex D Elastic Buckling Formulas for Beams with Double Symmetric Profiles (under Major-Axis Bending)

Annex E Local Buckling of Double Symmetric Profiles

Annex F Instability of Plates and Shells

Annex G Simplified Constitutive Interface Laws

Annex H Fatigue Testing

(for a total of about 170 pages)

• Index of the Prospect


• ASPECTS TO BE DEVELOPED IN STEP 2

As a result of the public inquiry, the main topics to be developed in further detail in Step 2 mainly concern sandwich panels and adhesively bonded joints.

Sandwich panels

General

Materials

Conceptual design of sandwich panels

Structural analysis

Generalities (Material hypotheses: linear/nonlinear face sheets/core materials behaviour,Shear in core material; Shear deformation; Core anisotropy; Boundary conditions; Out-of-plane stresses to be considered (curved panels); Local facing bending and core shear at facingdiscontinuities or core material changes; Creep and Temperature; Homogenization of thestructure (material level))

Imperfections (Geometrical imperfections; Pre-existing defects)

Calculation methods (Analytical calculation; FE Analysis)

Ultimate Limit States (Strength; Stability; Joints; Inserts)

Serviceability Limit States


Adhesively bonded joints

• The present version of the Prospect takes into account the configurations shown in Figure


• The structural verifications are addressed through an approach based on fracturemechanics by using interfacial constitutive laws of the type shown in Figure:

Adhesively bonded joints

• In Step 2, the purpose is to give provisions for both the cohesive failure, as well as theadhesive-adherent interface failure, the last one already analyzed in the Prospect.

• Another aim is to provide rules of good practice for the correct realization of glued joints.


The aim of this presentation has been to summarize and disseminate the activityalready developed by CEN/TC 250, as well as highlight the further procedures tobe followed on the road towards the publication of a structural Eurocodededicated to FRP structures.

The activity was addressed to:

ensure adequate reliability of such structures

promote a broader market for FRPs

assure their circulation between the EU countries, conforming to well-definedstandards

CONCLUSIONS

Thank you for your attention!

towards a structural eurocode for frp structures: … · construction of a pedestrian and cycle...

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