La inclusion del HRF como material con fines estructurales en el nuevo Codigo Modelo 2010

Transcription

1 La inclusion del HRF como material con fines estructurales en el nuevo Codigo Modelo 2010 Seminario sobre experienceas internationales del Hormigon Reforzado con Fibras 03 April Group Concrete Structures

2 Do we really need codes?...meeting TG 8.6 Marseille April

3 FRC and UHPFRC: one family or irreconcilable groups? fib TG 8.3 FRC fib TG 8.6 UHPFRC C20 C80 C180 C April

4 Softening versus hardening behaviour in axial tension Softening hardening 03 April

5 Softening versus hardening: hard to define Different response of structures made of FRC having a softening or hardening behaviour under uniaxial tension or bending 03 April

6 New Model Code for Concrete Structures Multi-level design strategy 03 April

7 Test for determing FRC properties in tension 03 April

8 Test for determing FRC properties in tension f R, j 3F l j 2bh 2 sp 03 April

9 Definition of strength intervals The strength interval is defined by two subsequent numbers in the series: 1,0 1,5 2,0 3,0 4,0 5,0 6,0 7,0 8,0.. [Mpa] wherease the letters a, b, c, d, e correspond to the residual strength ratios: a if 0,5 f R3k /f R1k 0,7 b if 0,7 f R3k /f R1k 0,9 c if 0,9 f R3k /f R1k 1,1 d if 1,1 f R3k /f R1k 1,3 e if 1,3 f R3k /f R1k 1,5 Example: a fibre concrete denoted with 3b has a strength between 3 and 4 Mpa and a f R3k /f R1k ratio ranging between 0,7 and 0,9 03 April

10 Constitutive design laws (Level I) Rigid plastic model: f Ftu f 3 R3 Linear model: f Fts f 0,45 R1 f Ftu f Fts wu CMOD 3 ( ffts 0,5 fr3 0,2 fr 1) 0 03 April

11 Design of FRC members: design in shear 0.18 Ftuk vrd, f k 100 l ) fck c fctk f 1/3 cp 03 April

12 Constitutive design laws (Level I) K-values added for different situations For isotropic fibre orientation K = 1,0 03 April

13 Bending moment [knm] The K-factor versus Design by Testing Y Mid-span deflection [mm] X Casting in Y-direction 03 April

14 Taking advantage of fibre orientation Production of precast elements for Haneda airport platform: determining the most favourable casting method in combination with design by testing 03 April

15 K-factor: relevance of casting method Unforeseen sliding surface in UHPFRC prestressed beam 03 April

16 Model Code for Concrete Structures Concrete s Design for structural safety Design for serviceability Design for durability Design for sustainability - Constitutive relations for wide range of concrete s - Fibres as a reinforcing material - Service life design - Reliable NLFEM analysis - Maintenance as a design issue - Conceptual design 03 April

17 Model Code for Concrete Structures Concrete s Design for structural safety Design for serviceability Design for durability Design for sustainability 03 April

18 Introduction of time in a structural design code Specification of conservation strategy Determination of tactic and regime for condition control Condition survey (after construction or re-design) Condition assessment (after construction or re-design) Revision of conservation strategy and tactic Recording Final adoption of inspection regime Start of through life condition monitoring Condition survey Condition assessment Condition evaluation and decision-making i = 1? n Execution of chosen intervention fib Model Code April

19 New interpretation of aspect of time with regard to design and maintenance of concrete structures 03 April

20 New interpretation of aspect of time with regard to design and maintenance of concrete structures 03 April

21 Assessing the residual capacity 03 April

22 Project Calandbridge the Netherlands 03 April

23 Removal of the asphalt layer 03 April

24 Preparing the steel surface 03 April

25 Applying the epoxy bond layer 03 April

26 Placement of the reinforcement 03 April

27 Leveling the new concrete 03 April

28 Typical characteristics of the new deck - Thickness of concrete deck 60 mm - Deck ready for use in 120 hours - Reduction of stress variation of 60% in bearing structure - Reduced vibration and noise 03 April

29 Model Code for Concrete Structures Concrete s Design for structural safety Design for serviceability Design for durability Design for sustainability 03 April

30 Model Code: design for sustainability Concrete s Level I Method Comparison of green house gas emission: material substitution: BREAM (UK), HQE (France), LEED (USA), CASBEE (Japan), Green Star (Netherlands) Level II Method Environmental Impact Calculation (EIC): - Measure of Embodied Energy - Measure of CO 2 - Calculation of Global Warming Potential (GWP) Level III Method Full life cycle assessment (LCA), including durability and maintenance considerations, recyle and reuse 03 April

31 EIC: Environmental Impact Calculation - CO 2 Emission - EE = Embodied Energy Energy consumed in the production of Portland Cement is estimated to be 4.88 MJ/kg and the total energy in the production of steel 23.7 MJ/kg (Struble and Godfrey (2004) - GWP = Global Warning Potential Contribution of CO 2 on global warming, calculated through the equivalence of the effect of greenhouse gas (Elrod, 1999): for simplicity: 100 year GWP = CO No x + 25CH 4 03 April

32 Comparison of two bridges (Voo/Foster, 2010) 03 April

33 Comparison of two bridges UHPC: - No shear reinforcement only fibres - f cm = 160 MPa 03 April

34 Comparison of two bridges (Voo/Foster 2010) 03 April

35 Two solutions for a 180 m long retaining wall (Voo/Foster, 2010) Construction of retaining wall for drain channel in Ipoh, Malaysia, 180 m long, 1.5 m high Solution in conventional concrete and UHPFRC (f cm =160 N/mm 2 ) 03 April

36 Results of EIC for retaining walls 03 April

37 GSE - Bridge Haneda Aiport Tokyo - Concrete girder C180 - Concrete deck C40-7 precast beams C April

38 GSE Bridge Haneda Airport Tokyo Advantages of the use of UHPFRC - 40% Weight reduction - 20% Reduction of cross-sectional depth (from 2.50 m to 2.00 m) - Durability 03 April

39 Concrete viaducts the Netherlands Reduction of height of concrete deck = hughe reduction of soil supply for bridge ramps 03 April

40 Model Code 2010 Design for structural safety Design for serviceability Design for durability Design for sustainability: elegance, beauty, harmony with environment, functionality, social value and acceptance, durability, reduction of nuisance for environment 03 April

41 Glenmore/Legsby pedestrian bridge Canada 2007 Span 53 m Suspended beams 34 m (h = 1,1 m) Crossing 8 traffic lanes Important aspects - Assembly in 8 hours - No intermediate support

42 Elegant structures in harmony with environment MuCem Marseille April

43 Balconies Denmark Foto B. Aarup Hi-con Denemarken 03 April

44 Balconies Poptahof Delft 2011 Proofloading 1500 kg/m 3

45 Conclusions - Adequate design recommendations for UHPFRC are a must : MC2010 gives a level I approach suitable for any fibre reinforced concrete -- Tailored recommendations ( Level II) are given for traditional concrete (RILEM) en HPFRC (fib TG 8.6) - UHPFRC can play an important role in service life design - UHPFRC is very suitable for retrofitting - Adequate criteria for sustainability of structures can become a hard argument for choosing this material - Architecture and functionality is a winning combination (conceptual design) 03 April