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
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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)
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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
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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)
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External Funded Research Projects
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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
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External Funded Research Projects
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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
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University of Warwick Collaborators (since 2005) - Thanks
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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)
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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)
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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/
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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
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No fatigue failure (after 2 million cycles) when the tensile load is
> 60% of the joint’s static resistance; at RT – Very promising
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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.
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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
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http://www2.warwick.ac.uk/fac/sci/eng/staff/jtm/jtm_acic_2013_net
_tension_strength_17_09_13.pdf
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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
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N. Matharu, 'Aspects of Bolted Connections for Fibre Reinforced
Polymer Structures,' PhD Thesis, Warwick Uni., Sept. 2014.
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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 *.
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* Open access at http://wrap.warwick.ac.uk/64033/
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Recognised Design Guidance
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‘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.*
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* I was a corresponding contributor
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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.
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J.T.Mottram@warwick.ac.uk

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