DEÁN, MURALLA DE / SIGLO XVI

Assessing of rebar stresses

An improved method is needed for assessing rebar stress ranges based on non- destructive testing results, e.g. the change of crack opening as a function of the applied load during inspection. Only a preliminary, conservative approach is given in this work. Improved information for high traffic loads

Operational load factors for calculating the stress range at the general and first detailed fatigue examination should be developed also for existing bridges (with service lives shorter than 100 years).

Furthermore, traffic load frequency, magnitude and configuration data should be more accurate for fatigue life calculations. Realistic traffic models for predicting future traffic loads should be established for specific railway networks.

Welded and corroded rebar

The performance of welded and corroded rebar should further be studied.

Detecting initial rebar fatigue fracture in a distributed reinforcement of a bridge element It is proposed to use periodic crack-opening displacement measurements as method for detecting rebar fractures. This method should be further developed and calibrated through experimental testing. Other potential methods (e.g. electro magnetic testing) should be developed and tested to facilitate non-destructive punctual evaluations of rebar fracture in a bridge element at special condition surveys.

Fatigue strengthening with UHPFRC

The method for dimensioning the UHPFRC-layer in composite reinforced concrete-UHPFRC elements employed in this work is based on maximum cyclic action effect values. Tensile fatigue tests on pure UHPFRC specimens should be conducted to investigate the effect of variable cyclic loading to potentially develop a less conservative dimensioning method.

Appendix A: UHPFRC recipe

Appendices

Appendix A: UHPFRC recipe

Note: The UHPFRC recipes used in this study belong to the family CEMTECmultiscale® developed

by Dr. P. Rossi – LCPC Paris, and modified at MCS-EPFL for the application to rehabilitation.

CEMTECmultiscale® and recipes are covered by the French patent applications #FR2806403 and

#FR2806404 (both published on 9th September 2001) and by the PCT patent application WO0168548 (published on 9th September 2001).

Appendix B: Crack pattern of the UHPFRC upper face

Appendix B: Crack pattern of the UHPFRC upper face

N=17'600 N=349'000 N=2'194'000 N=2'393'800 N=1 N=0 w=0.5...1.3 mm w=0.4 mm w=0.3 mm O2 W4 O1 O7 O5 O4 O3 O6 W5 O1'

Figure 93: Beam P9 (NR15) – position of the Ω - gages and crack pattern of the UHPFRC layer at the end of load level a load level b N= 13'003'000 load level a N=1'667'600 w=0.1 mm O5 O4 O3 O2 O6 W5 w=0.1 mm O7 w=0.1 mm O1 W4 O7 Fracture test at N = 13'003'000

Figure 94: Beam P10 (NR15) – position of the Ω - gages and crack pattern of the UHPFRC layer at the end of load levels a and b

Reinforced concrete bridges under increased railway traffic loads 116 w=0.1 mm load level b w>0.1 mm N=30'000 N=5'000 O2 O1 O3 O4 O5 w=0.1 mm O7 O6' N=60'000 N=500'000 N=7'400'000 load level a

Figure 95: Beam P5 (NR30) – position of the Ω -gages and crack pattern of the UHPFRC layer at the end of load levels a and b N=30'400 N=500'000 N=1 N=575'000 N=10'846'000 load level a load level b O7 w=0.1 mm w=0.1 mm w>0.1 mm O2 O3 O4 O5 O1

Figure 96: Beam P6 (NR30) – position of the Ω -gages and crack pattern of the UHPFRC layer at the end of load levels a and b

Appendix B: Crack pattern of the UHPFRC upper face O7 w>0.1 mm N=294'000 N=190'000 N=1 (F = 30 kN) N=1 (F = 20 kN) N=0 W4 O1 O2 O3 O4 O5 O6 W5

Figure 97: Beam P7 (R50) – position of the Ω -gages and crack pattern of the UHPFRC layer at the end of load level e N=40'000 N=1 N=1'181'000 N=1'723'000 N=1'257'000 N=635'000 N=7'056'000 load level a load level b load level c load level d load level e O7 w=0.1 mm O1 W4 O2 O3 O4 O5 O6 W5

Figure 98: Beam P8 (R50) – position of the Ω -gages and crack pattern of the UHPFRC layer at the end of load levels a, b, c, d and e

Andrin Herwig

Curriculum Vitae

[email protected] Birth date: September 7, 1969 Nationality: Swiss

Professional experience Assistant /

PhD student

Mai 2003-Jan. 2008

at the Laboratory of Maintenance and Safety of Structures (MCS) of Prof Dr. E. Brühwiler, École Polytechnique Fédérale de Lausanne EPFL;

Main research: Dynamic behaviour of railway bridges, fatigue of reinforced concrete bridges, fatigue behaviour of UHPFRC. Conducting laboratory tests within the frame of the thesis and mandates. Dynamic measurements at a railway bridge.

Associated project: European research project Sustainable Bridges – Assessment for Future Traffic Demands and Longer Lives; technical and editorial contributions to the Guideline for Load and Resistance Assessment of Existing European Railway Bridges.

Mandates: • Laboratory tests for the determination of the load carrying behav-

iour of cantilever connection elements ARBO®_{. Mandate of the}

enterprise F. J. Aschwanden AG, Lyss, Switzerland.

• Widening of the driving surface of the Felsenauviadukt, Berne; laboratory tests for the determination of the load carrying behav- iour of elements connecting new exterior struts and the existing bridge structure. Mandate of the Canton Berne Civil Engineering Office, Switzerland.

• Tests for the fabrication and determination of the load carrying capacity of concrete articulations in UHPFRC. Mandate of the “Hes- sisches Landesamt für Strassen und Verkehrswesen“, Wiesbaden, Germany.

Teaching: Assistant of the course Maintenance of Structures, mentor- ing/supervision of students and Master students in Civil Engineering and Architecture

Reinforced concrete bridges under increased railway traffic loads

120

Structural engineer

1996-2002 Design of reinforced concrete structures (bridge, building, immobile

parts for detachable chairlifts), steel structures, composite struc- tures, proof engineer for chairlifts at:

- Niederegger und Züger, Ingenieurbüro, Samedan, Switzerland, - Fredy Unger Ingenieurunternehmung, Chur, Switzerland, - Gruner AG Ingenieure und Planer, Basel, Switzerland, - Ingenieurbüro Straub AG, Chur, Switzerland.

Education and Diploma

Jan. 2008 Grade doctor ès sciences, École Polytechnique Fédérale de Lau-

sanne (EPFL), Lausanne, Switzerland.

1996 Degree in civil engineering (dipl. Ing.) at the École Polytechnique

Fédérale de Lausanne (EPFL), Lausanne, Switzerland.

1991 Pre-diploma in architecture (exam passed) at the Swiss Federal Insti-

tute of Technology Zurich (ETH), Zurich, Switzerland.

1990 „Matura Typus C“ at the „Evangelische Mittelschule Schiers (EMS)“,

Schiers, Switzerland. Languages German: English: mother tongue very good French: Spanish: very good basic knowledge Publications

Herwig A. (2006), Consideration of the dynamic effect of increased train loads for the fatigue examination of concrete bridges, Proceedings, 6th International PhD Symposium in Civil Engi- neering, Zurich, 23-26, August 2006.

Herwig A. & Brühwiler E. (2006) Accurate fatigue stress determination in concrete railway bridges considering rail track-structure interaction, in proceedings for conference « IABMAS» in Porto July 2006.

Herwig A. (2005) Ermüdungsversuche mit Mischbauteilen aus ultra hochleistungsfähigem Fa- serfeinkornbeton und Stahlbeton, Tagungsband Doktorandensymposium 45. Forschungskollo- quium des DAfStb in Wien 6. – 7. Oktober.

Herwig A. & Denarié E. (2005) Fatigue behaviour of elements combining ultra-high perfor- mance fibre reinforced concrete and reinforced concrete, Test report European research pro- ject SAMARIS

E. Brühwiler, E. Denarié, M. Maître, and A. Herwig (2004) Optimierung des Betoniervorgangs und der Mindestbewehrung einer massiven Bodenplatte. Beton- und Stahlbetonbau: Interna- tionales Organ für Betonbau, 99(2):114-121, 2004.