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<strong>Non</strong>-<strong>Finito</strong><br />
∆αναΐδες<br />
Danaid<br />
Auguste Rodin, 1901
<strong>Non</strong>-<strong>Finito</strong><br />
“<strong>Non</strong> <strong>Finito</strong>” is a sculpting technique<br />
literally meaning that the work is<br />
unfinished.<br />
<strong>Non</strong> finito sculptures appear unfinished<br />
because the artist only sculpts part of the<br />
block, leaving the figure appearing to be<br />
stuck within the block of material.
<strong>Non</strong>-<strong>Finito</strong> = simply<br />
uncompleted work<br />
Urs Meier<br />
EMPA, Swiss Federal Laboratories for<br />
Materials Science and Technology
Outline<br />
• The Past<br />
• The Present<br />
• The Future<br />
• Conclusions
Outline<br />
• The Past<br />
• The Present<br />
• The Future<br />
• Conclusions
Post-strengthening with externally<br />
bonded steel plates since 1967<br />
• heavy<br />
• many joints<br />
• scaffolding required<br />
• corrosion
Corrosion<br />
built in 1912<br />
strengthened: 1980<br />
photo taken: 2006
1985<br />
94 kg versus 4.5 kg<br />
• CFRP not<br />
known in CE<br />
community<br />
• (if known,<br />
absolutely<br />
not<br />
accepted)
Strengthening with CFRP<br />
• light<br />
• no corrosion<br />
• no scaffolding<br />
• no joints<br />
• outstanding fatigue<br />
performance
World’s first CFRP strip application<br />
Ibach bridge 1991
Ibach bridge 1991<br />
CFRP strips are going to be<br />
prepared<br />
Ibach bridge 1991<br />
only 6 working hours!
„Structural Wallpaper“, daily business<br />
In average 20% cheaper<br />
due to less labor hours
Patience, patience, patience ………..<br />
160<br />
140<br />
120<br />
100<br />
80<br />
60<br />
40<br />
first idea<br />
feasibility o.k.<br />
tons of CFRP in CH<br />
1982 1987<br />
0<br />
20<br />
1991 1993 1995 1997 1999 2001<br />
13 years
Outline<br />
• The Past<br />
• The Present<br />
• The Future<br />
• Conclusions
CFRP wires and strips<br />
• very high strength: 3000 MPa<br />
• high stiffness: 150 … 600 GPa<br />
• lightweight: 1.5 t/m 3<br />
• no corrosion<br />
• no stress corrosion<br />
• outstanding fatigue<br />
performance<br />
• no stress relaxation
Parallel wire bundles<br />
241 wires<br />
(each 5 mm)<br />
ultimate load: 12 MN
Stork bridge 1996 (124 m span, 2 lanes)
Easy to handle CFRP tendons<br />
3 MN Unit<br />
Andreas Winistörfer
Laminated CFRP<br />
strap
Pin loaded, laminated CFRP strap<br />
σ σ τ // ⊥<br />
//⊥<br />
Andreas Winistörfer
Laminated CFRP<br />
strap
σ // σ ⊥<br />
τ //⊥<br />
non-laminated straps<br />
laminated<br />
non-laminated
Relative strength vs. radii<br />
ro<br />
0.80<br />
r i<br />
σ f / σ UTS<br />
0.70<br />
0.60<br />
0.50<br />
0.40<br />
0.30<br />
0.20<br />
0.10<br />
Werne 1<br />
Werne 2<br />
Werne 3<br />
US-Army<br />
Oser 1<br />
Oser 2<br />
Winistoerfer<br />
σ<br />
c<br />
σ c<br />
Andreas Winistörfer<br />
0.00<br />
1.00 1.10 1.20 1.30 1.40 1.50 1.60 1.70 1.80<br />
r o / r i
Answer: very thin laminate (0.12 mm)
σ // σ ⊥<br />
τ //⊥<br />
non-laminated<br />
laminated
Strain versus load<br />
1.6<br />
1.4<br />
1.2<br />
Strain [%]<br />
1<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
Layer 10<br />
Layer 6<br />
Layer 4<br />
Layer 2<br />
Layer 1<br />
0<br />
0 5 10 15 20 25 30<br />
Load [kN]<br />
Andreas Winistörfer
Efficiency<br />
300<br />
250<br />
Capacity [kN]<br />
200<br />
150<br />
100<br />
50<br />
0<br />
1 10 20 30 40 50 60 70<br />
Andreas Winistörfer<br />
Number of layers [N]
Creep experiments<br />
0.10<br />
Creep Strain [%]<br />
0.08<br />
0.06<br />
0.04<br />
0.02<br />
80 % von UTS<br />
0.00<br />
0 100 200 300 400 500 600 700<br />
Time [h]
Creep experiments
Creep experiments<br />
• 92 % of UTS since 8 years<br />
– 1 sample failed after 8 years<br />
– 1 sample is still running<br />
After a first “consolidation” scarcely no<br />
more creep
Cross section of T-Beam
Cross section of T-Beam
Cross section of T-Beam
Cross section of T-Beam
Cross section of T-Beam
Cross section of T-Beam
Shear strengthening
Applications since 2003
Cable dredger
America's Cup Winner 2007 in Valencia Alinghi<br />
with Pin Loaded CFRP-Stays
Juli 2009
Roof trusses of<br />
church Homberg-Efze
Roof truss of church Homberg-Efze<br />
Dr. A. Winistörfer and Dr. U. Huster
Remote monitoring of roof truss of church<br />
Dr. R. Brönnimann
Seismic retrofitting of masonry walls<br />
with<br />
pre-tensioned CFRP straps<br />
each<br />
tendon<br />
360 kN
high stress<br />
concentration<br />
at the corners<br />
σ //<br />
similar for<br />
σ ⊥<br />
//<br />
τ //⊥<br />
and<br />
//⊥
The Dome of Pavia<br />
lantern<br />
62 m<br />
41 m<br />
dome<br />
tambour<br />
arcs<br />
columns<br />
Andrea Meier, Prof. E. Brühwiler, Prof. G. Macchi<br />
octagon
Selected Problems of Dome<br />
Lack of<br />
cohesion of<br />
the different<br />
structural<br />
components<br />
Andrea Meier, Prof. E. Brühwiler, Prof. G. Macchi
Selected Problems of Dome<br />
possible<br />
mechanisms of<br />
collapse<br />
Andrea Meier, Prof. E. Brühwiler, Prof. G. Macchi
Selected Problems of Dome<br />
possible concept<br />
for rehabilitation:<br />
horizontal posttensioned<br />
CFRP<br />
straps<br />
and adhesively<br />
bonded fabrics<br />
Andrea Meier, Prof. E. Brühwiler, Prof. G. Macchi
Solution<br />
possible concept<br />
for rehabilitation:<br />
horizontal posttensioned<br />
CFRP<br />
straps<br />
Andrea Meier, Prof. E. Brühwiler, Prof. G. Macchi
Tensioner for CFRP straps
Worldwide thousands of columns need<br />
additional confinement!
CFRP wrapping of circular columns<br />
Cross section<br />
of RC column<br />
uniform<br />
confinement<br />
Increase of confinement<br />
by CFRP wrapping for<br />
circular columns: state<br />
of the art!
CFRP wrapping of rectangular columns<br />
Cross section<br />
of RC column<br />
Increase of confinement<br />
by CFRP wrapping for<br />
rectangular columns:<br />
state of the art!<br />
imbalanced<br />
confinement<br />
Very high stress<br />
concentration with<br />
laminated wet-lay-up
Active column wrapping<br />
cross section of<br />
column
Active column wrapping<br />
woven fabric<br />
pressure hoses
Woven fabric pressure hoses<br />
6 cm
Active column wrapping<br />
woven fabric<br />
pressure hoses<br />
40 cm
Active column wrapping<br />
wrapping of 0.12 mm<br />
thick CFRP-tape
Active column wrapping<br />
injecting polymer mortar<br />
with high pressure
Active column wrapping<br />
injecting polymer mortar<br />
with high pressure
Active column wrapping<br />
injecting polymer mortar<br />
with high pressure<br />
“octagon”
Active column wrapping<br />
12 mm<br />
min. radius =10 mm
Active column wrapping<br />
Mark Green, Olav Huth, Andreas Winistörfer
CFRP Column Wrapping 1995<br />
XXSYS Technologies, Frieder Seible et all.
CFRP Column Wrapping 1995<br />
XXSYS Technologies, Frieder Seible et all.
Active column wrapping
Mark Green, Olav Huth, Andreas Winistörfer
Active column wrapping<br />
Force [kN]<br />
Reference column<br />
Enormous gain on<br />
“systems ductility”, even<br />
when all single<br />
components are brittle<br />
materials!<br />
Deformation under compression [mm]<br />
Confined column<br />
(6 layers of<br />
thermoplastic<br />
CFRP tape of<br />
0.12 mm<br />
thickness each,<br />
pre-stressed by 2<br />
hoses at each<br />
column side)<br />
Maximum Load:<br />
3713 kN<br />
Maximum<br />
displacement: -<br />
63.8 mm (at<br />
failure)
Dr. Hanspeter Kaiser (1989)<br />
Prof. Dr. Thanasis Triantafillou (1992)<br />
Dr. Martin Deuring (1993)<br />
Dr. Andreas Winistörfer (2002)<br />
Dipl. Ing. Iwan Stöcklin (2002)
Dr. Hanspeter Kaiser (1989)<br />
Prof. Dr. Thanasis Triantafillou (1992)<br />
Dr. Martin Deuring (1993)<br />
Dr. Andreas Winistörfer (2002)<br />
Dipl. Ing. Iwan Stöcklin (2002)
Pre-tensioning equipment<br />
Type: tensioning head
Application of pre-tensioned CFRP strips
Verification experiment<br />
Christoph Czaderski
Spannrahmen
Mechanised and computer-controlled<br />
equipment needed!
5 hours ≡ 1.45 m
5 hours ≡ 1.45 m<br />
5 hours ≡ 1.45 m
5 hours ≡ 1.45 m<br />
5 hours ≡ 1.45 m
Pre-tensioned CFRP strips<br />
• Why still a challenge?<br />
• High qualified staff needed!<br />
• C-fiber producer will sell less fibers for<br />
each case!<br />
• Producers of adhesives will sell less<br />
adhesives!
Outline<br />
• The Past<br />
• The Present<br />
• The Future<br />
• Conclusions
Heritage structures: Post-tensioning<br />
with a CFRP mono wire system
Heritage structures: Post-tensioning<br />
with a CFRP mono wire system<br />
2 mm
Heritage structures: Post-tensioning<br />
with a CFRP mono wire system
Post-tensioning with a CFRP mono<br />
wire system<br />
US Pat. 4‘442‘908 US Pat. 5‘423‘389 US Pat. 5‘017‘057
Hagia Sophia, Istanbul<br />
since 641 prone to<br />
seismic risk<br />
CFRP strips ???
Airbags save lives in the automotive<br />
sector!
Airbags save lives in the automotive<br />
sector!<br />
Why not in<br />
structural applications?
Huge airbags enable safe landing of<br />
space crafts
Hagia Sophia, Istanbul<br />
high risk zone<br />
A. Çakmak, A. Moropoulou & C. L. Mullen
Hagia Sophia, Istanbul<br />
telescopic<br />
columns
Hagia Sophia, Istanbul<br />
crosshead<br />
U-profile
Hagia Sophia, Istanbul<br />
inside<br />
U-profile<br />
folded<br />
airbag
Hagia Sophia, Istanbul
Case Bronx-Whitestone Bridge
1943: to avoid another “Tacoma-Case”
Bronx-Whitestone Bridge<br />
1943, installation<br />
of 4.3 m<br />
high trusses<br />
on ……..
Bronx-Whitestone Bridge<br />
1943, installation<br />
of 4.3 m<br />
high trusses<br />
on either side<br />
of the deck to<br />
stiffen and<br />
weigh down<br />
the girder in<br />
an effort<br />
to reduce<br />
oscillation.
Cross Section 1943 until 2003<br />
Cable<br />
7620<br />
3350 4270<br />
Floor<br />
additional<br />
Stiffening<br />
Trusses<br />
6,000 t<br />
Floor Beams and Stringers<br />
22560
Some Problems with Suspension Bridges<br />
Main cables:<br />
- prone to corrosion<br />
- not prone to fatigue<br />
Suspender cables:<br />
Suspender cables:<br />
- prone to corrosion<br />
- prone to fatigue
until 2003 Loss of Cable Cross Section<br />
Cable<br />
20 to 25% loss due to corrosion!<br />
Cable<br />
7620<br />
3350 4270<br />
Close in each direction one lane?<br />
Floor<br />
Floor Beams and Stringers<br />
22560
2003: GFRP-Wind Fairings<br />
Cable<br />
Suspender<br />
wind
2003: GFRP- Wind Fairings<br />
May 2003 until October 2003<br />
installation of<br />
2200 m long 400 tons of GFRP<br />
vacuum assisted resin transfer<br />
molded<br />
(VARTM) wind fairings
Net weight “loss” of 5’600 tons<br />
corresponds to: 67 train engines each 84 t
GFRP Fairings Bronx-Whitestone<br />
Bridge
What happens when another 20% is<br />
gone???
Closing of two of the six lanes???<br />
Rush hour traffic<br />
1950ties today
What if we get to-morrow a contract for<br />
CFRP Cables for Bronx Whitestone?
Additional Main Cables (steel !!!)<br />
25th April Bridge in Lisbon
Hanger-/Main-Cable Connection<br />
Humber Bridge<br />
Golden Gate Bridge
Hanger-/Main-Cable Connection<br />
3 MN Unit<br />
Golden Gate Bridge
2003: Passive FRP- Wind Fairings<br />
Cable<br />
Suspender<br />
wind
20XX: Adaptive Wind Fairings<br />
M<br />
wind
20XX: Adaptive Wind Fairings<br />
M<br />
wind
20XX: Adaptive Wind Fairings
Outline<br />
• The Past<br />
• The Present<br />
• The Future<br />
• Conclusions
Conclusions<br />
• The idea to use CFRP for rehabilitation<br />
was called „crazy” in the 1980ties<br />
• Today it is state-of-the-art
Conclusions<br />
• The idea to use e.g. airbags to preserve<br />
civil structures will be called “crazy” these<br />
days.<br />
• This or similar “crazy” concepts might be<br />
state of the art in 5, 10 or 20 years<br />
• It is only a question of patience and time.<br />
• however
Recommendations for today<br />
In practice we should focus on challenges in<br />
the present time like:<br />
• Pre-tensioned CFRP strips<br />
• Easy to handle CFRP tendons<br />
Here is great potential and everything<br />
proofed to be reliable and ready!
Thank you very much for your<br />
kind attention
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