23/04/2015 Structural Engineering Research at Warwick University for Design Guidance J. Toby Mottram, Professor Civil Research Group NGCC Research Showcase Event NCC 23rd April 2015 work Composite structures of PFRP shapes and systems 2 First generation shapes with steel bolted connections 40 m Fiberline footbridge in Kolding, Denmark, 1997 Launder Aqueduct, Oxfordshire – Network Rail, 2007(Structural Engineer Tony Gee & Partners) work 1 23/04/2015 Composite structures of PFRP shapes and systems 3 Startlink house and characterization of M-f response of joints for portal frame action Temporary structure at church in L’Aquila, Italy, 2010 – testing of built-up columns work PFRP shapes and systems topics (since 2005) 4 Outcomes to provide engineering information for the preparation of (recognised and verified) guidance acceptable in a national/international design standard: • Designing structures for durability (DURACOMP project to be introduced) • Members in bending – lateral torsional buckling (ltb) • Seismic design and dynamic response (with Iuav at Venice) • Built-up members in compression (at Venice) • Bolted connections and joints: • • Modes of failure and strength formulae (plate-to-plate connections) • Moment-rotation and tying force characteristics for frame joints • Slip and fatigue resistant for bridge engineering • Effect of temperature on resistance (with Monash University) • Initiation and progression of damage to ultimate failure using ABAQUS Structural engineering for Startlink housing system (portal frame action) work 2 23/04/2015 External Funded Research Projects 5 Connections and Joints for Buildings and Bridges of Fibre Reinforced Polymer, from 01/10/10 to 31/03/14 (EP/H042628/1) Bridge Engineers Mott McDonald & Access Design and Engineering Providing Confidence in Durable Composites (DURACOMP), Multi-university project funded by the 2012 Ground and Structural Engineering Call from 01/05/13 to 30/04/16 (EP/K026925/1). Toby Mottram (PI), Mark Evernden (Bath), Wendel Sebastian (Bristol), Chris Pearce & Lukasz Kaczmarczyk (Glasgow), Phil Purnell (Leeds) and Peter Gosling & Chris Kilsby (Newcastle). Aquamarine Power Ltd., Formax UK Ltd., Highways Agency and Parsons Brinckerhoff Characterising Dynamic Performance of Fibre Reinforced Polymer Structures for Resilience and Sustainability, Dr Stana Zivanovic (PI) from 01/10/15 to 30/09/18 (EP/M21505/1) Larkfleet Homes, Network Rail, Optima Projects Ltd., Sinclair Knight Merz(Europe) Ltd. (Jacobs), Swiss Federal Laboratories of Material Science and Technology EMPA, The Univ. Iuav (Venice) and Univ. of Exeter work External Funded Research Projects 6 PFRPStruJoin - Structural Joints for Building Frames of Pultruded Fibre Reinforced Polymers - A two year Marie Curie European Intra-Fellowship with Dr. Ana M. Girão Coelho from 01/08/13 to 31/07/15 Standard for Load Resistance Factor design (LRFD) of Pultruded FiberReinforced Polymer (FRP) Structures, Sub-agreement with Univ. of Wisconsin-Madison (USA), from 01/01/08 to 09/11/10 (Pre-standard published). $1.3m from the American Composites Manufacturers Association Startlink Lightweight Building System, Technology Strategy Board (Low Impact Building Competition of Summer 2008. EXEL Composites (project PI), and six partners (Startlink Ltd., John Hutchinson Architect, Larkfleet Homes, OCS Plastics, Optima Projects Ltd. and Costain). Ended November 2012 work 3 23/04/2015 University of Warwick Collaborators (since 2005) - Thanks 7 EIF - Dr. Ana M. Girão Coelho (01/08/13 to 31/07/15) PhD and Postdoc - Dr. Behrouz Zafari (01/10/09-) Postdoc – Dr. Jawed Qureshi (01/12/10 to 31/05/13) PhD students - Dr. Navroop Matharu (2015); Dr. Thuy Nguyen Tien (2014); Dr. Mark Evernden (2006); Dr. Abbaker Elnur Abbaker (2006) and Dr. Cyprien Lutz (2005); Alfred Gand (01/10/12-) Closed PFRP sections; member and joint behaviour Colleagues: Dr. Tak-Ming Chan (now HK Polytechnic Uni.); Salvatore Russo, Dr. Giosuè Boscato and Carlo Casalegno (Iuav) work 8 DURACOMP Project WP1: Multiscale modelling WP2: Material characterisation Modelling 50% probability Autumn 10% probability WP5: dissemination/ management/ national importance 90% probability Testing WP3: Stochastic reliability analysis Probability density Summer WP4: Structural component testing Change in precipitation (%) E11 (GPa) 8 4 23/04/2015 9 Outcomes and Impact (since 2005) Publications: ’20’ journal and ’20’ conferences papers, contributions to ASCE pre-standard and CEN TC250 WG 4 Technical Report Full list at: http://www2.warwick.ac.uk/fac/sci/eng/staff/jtm/jtm_publications.pdf Presentations at: http://www2.warwick.ac.uk/fac/sci/eng/staff/jtm/presentations/ ‘Freely’ available are two literature databases (regularly updated). PFRP shapes and systems (2300 entries): http://www2.warwick.ac.uk/fac/sci/eng/staff/jtm/pfrp_latest.pdf For the DURACOMP project (500 entries): http://www2.warwick.ac.uk/fac/sci/eng/duracomp/dissemination/ work 10 Impact Highlights (since 2005) Resin injected bolted connections for slip and fatigue resistance Top washer Grips of DARTEC Joint 1&2 Bolt hole Nut 0.40 Displacement (mm) Tension strength is 75 kN Bottom washer LVDT 1&2 48 kN R =0.1 0.30 40 kN R =0.1 0.20 32 kN R =0.1 0.10 LVDT 3&4 Joint 3&4 0.00 0 500000 1000000 Number of Cycles 1500000 2000000 Fatigue test rig with specimen work No fatigue failure (after 2 million cycles) when the tensile load is > 60% of the joint’s static resistance; at RT – Very promising 5 23/04/2015 11 Impact Highlights (since 2005) Startlink all FRP portal frame joint - dowel and adhesive bonding B. Zafari and J. T. Mottram,work ‘Characterization by full-size testing of pultruded frame joints for the Startlink house,’ Journal of Composites for Construction, 19 1, 2015, pp. 9. 12 Impact Highlights (since 2005) Strength formulae for the design of multi-row bolted connections failing in net tension w = 2e2 Tension load (1-Lbr) Rnt,f/2 e1 Tension stress due to LbrRnt,f (1-Lbr) Rnt,f/2 Row 2 First bolt row s = 4d min. d dn LbrRnt,f/2 Tension stress due to (1-Lbr)Rnt,f Peak stress at hole due to bearing load Peak stress at hole due to bypass load LbrRnt,f/2 Row 1 n d A stress at free edge t Hole centre Tension load A stress at free edge Hole centre A t Rnt,f Rnf,t = rf w t Rnt,f Minimum value of rf is 0.2. Provides a simple formula for practitioners to use work http://www2.warwick.ac.uk/fac/sci/eng/staff/jtm/jtm_acic_2013_net _tension_strength_17_09_13.pdf 6 23/04/2015 13 Impact Highlights (since 2005) | 13 Partial factors using the standard evaluation procedure of Eurocode 0 (Appendix D) b Experimental Value, Re (kN) 80 • • • • 60 Vrt = 0.22 Vd = 0.005 Vt = 0.03 Vfbr = 0.06 Rk = 0.75 40 20 – Calculated values • Characteristic resistance, Rk – Standard reliability • Establish gM 0 0 131 Tests 20 Resistance model Rt vs Re Estimate Correction, b CoV of Variables, Vrt 40 60 Design Value, Rt (kN) 80 work N. Matharu, 'Aspects of Bolted Connections for Fibre Reinforced Polymer Structures,' PhD Thesis, Warwick Uni., Sept. 2014. 14 Impact Highlights (since 2005) Partial factors determined for pin-bearing mode of failure in bolted connections gM = 1.4 Material PFRP gM ASCE Pre-Standard 1.25 EUROCOMP 2.15 Timber (EC5) 1.3 Steel (EC3) 1.25 Aluminium (EC9) 1.25 Available Fbr,k not statistically verified gM = gm1 (Properties) + gm2 (Cure) + gm3 (Environmental effects ) For ltb failure of members in bending (gM = 1.14 to 1.19), in T. N. Tien, 'Lateral-torsional Buckling Resistance of Pultruded Fibre Reinforced Polymer Shapes,' PhD thesis, May 2014 *. work * Open access at http://wrap.warwick.ac.uk/64033/ 7 23/04/2015 Recognised Design Guidance 15 ‘Load and Resistance Factor Design (LRFD) of Pultruded Fiber-Reinforced Polymer (FRP) Structures’ http://www2.warwick.ac.uk/fac/sci/eng/staff/jtm/composite_e ngineering_show_12_11_2014.pdf Fiber Composite and Polymer Standards (FCAPS) ASCE Standard Committee • Accredited by the American National Standards Institute (ANSI) • 28 Ballots as of December 2014 • Publication date UNKNOWN ‘Guidance for the Design of FRP Bridges’ ad hoc group with NGCC. ‘Fiber Reinforced Polymer Structures,’ Scientific and Technical Report, WG4 of CEN/TC 250 for EN structural design codes (Eurocodes).* ‘Revised CUR96 FRP Composite Structures,’ The Netherlands.* work * I was a corresponding contributor 16 Concluding Remarks (Personal) • In 2005 the level of activity and interest in structures of FRP shapes and systems was relatively low. • Today the community wants to exploit ‘Composites in Construction’ and so there’s a strong desire for reliable and relevant design guidance to make ‘FRP shapes and systems’ an option. • Structural engineering research at Warwick University with PFRP shapes and systems is aimed at disseminating technical/scientific/engineering information that can be used to prepare improved/new design guidance. • Key is for those with understanding and knowledge to have time to review, evaluate and calibrate what we know, and with the community-at-large work to fill in gaps in knowledge. • There should be no impediment to the UK having, say in five years, design guidance that matches the aspirations/expectations of the stakeholders. work J.T.Mottram@warwick.ac.uk 8