Design Guidelines A Scandinavian Approach

Transcription

1 Design Guidelines A Scandinavian Approach Pro. Björn Täljsten Luleå University o Technology SWEDEN Presented by Tech. Lic Anders Carolin 1 Pro. B. Täljsten Departmento Civiland Mining Engineering Division ostructuralengineering

2 Agenda Coninement Saety actors Strengthening in Strengthening in Strengthening in Saety actors Acknowledgement 2 Pro. B. Täljsten Departmento Civiland Mining Engineering Division ostructuralengineering

3 Why the need or design guidelines? Coninement Saety actors Increased need or strengthening and rehabilitation New materials introduced Knowledge how to use these materials or strengthening is relative limited compared to traditional building materials To gain acceptance within the building industry 3 Pro. B. Täljsten Departmento Civiland Mining Engineering Division ostructuralengineering

4 Strengthening o Structures in General Holes Slabs NSMR Coninement Saety actors Beams Columns Brick Walls Steel Collar 4 Pro. B. Täljsten Departmento Civiland Mining Engineering Division ostructuralengineering

5 The start The work with the guidelines started 1998 in relation to a strengthening work o a rail road bridge Coninement Saety actors It was elt rom the Rail Road authorities that a guideline was needed i the techniques should be accepted to be used on railroad and the like 5 Pro. B. Täljsten Departmento Civiland Mining Engineering Division ostructuralengineering

6 The start The guideline is divided in our main parts Coninement Saety actors part that explain the use o advanced composites or strengthening Comprehensive theoretical part that give a clear understanding o the design process part which explain how the strengthening work shall be carried out Finally appendices with design examples and material data or use 6 Pro. B. Täljsten Departmento Civiland Mining Engineering Division ostructuralengineering

7 The start The most essential in the codes considered to be: P 1 DP Strengthening or bending DP q Coninement Saety actors Saety actors d Strengthening or shear ηγ k m γ n But But also also atigue, torsion and and coninement are are considered and quality control 7 Pro. B. Täljsten Departmento Civiland Mining Engineering Division ostructuralengineering

8 Strengthening or bending Failure modes Coninement Saety actors 1. Compressive ailure 2. Yielding, tensile rein. 3. Yielding, compressive rein. 4. Tensile ailure, laminate 5. Anchorage ailure 6. Peeling ailure 7. Delamination In general: M A ' s ' y ( ) 0.4x d + A ( d 0.4x) + ε E A ( h 0.4x) ' s s y s 8 Pro. B. Täljsten Departmento Civiland Mining Engineering Division ostructuralengineering

9 Strengthening or bending Design Coninement Saety actors In general (depending on expected ailure mode): M A ' s ' y ( ) 0.4x d + A ( d 0.4x) + ε E A ( h 0.4x) ' s s y s 9 Pro. B. Täljsten Departmento Civiland Mining Engineering Division ostructuralengineering

10 Anchorage l a l cr 0.2 ct E d w t Coninement Saety actors Based on racture mechanics 10 Pro. B. Täljsten Departmento Civiland Mining Engineering Division ostructuralengineering

11 4,0 End-peeling 3,0 Analytical calculation 2,0 Coninement 1,0 FE - analysis 0, Saety actors 2,0 1,5 1,0 0,5 0,0 Analytical calculation FE - analysis Peeling τ max Ga P 2sE W c c ( 2l + a b)( aλ + 1) l + a λ 2-0, λ G a s b E 1 A + 1 E A c c + z c 0 E W c 11 Pro. B. Täljsten Departmento Civiland Mining Engineering Division ostructuralengineering

12 Failure criteria Coninement σ 1 σ 1 < ct 2 σ x + σ y σ x σ y 2 xy τ 1 2 Saety actors σ x M I 2 x ( h x) 12 Pro. B. Täljsten Departmento Civiland Mining Engineering Division ostructuralengineering

13 - Design Failure modes Coninement Saety actors 1. Compressive ailure in the concrete 2. Tensile ailure (ibre) in composite 3. Anchorage ailure 13 Pro. B. Täljsten Departmento Civiland Mining Engineering Division ostructuralengineering

14 - Design In general: V V + V + d c s V q(x) q(x) Coninement Saety actors VA V0 τζη ση z V0 Fζη VA α β' α β' zcotα zcotβ' σζ τζη T θ τζη ση Fζ How to calculate V? A B A B θ θ 90 β V 90 β V 90 α 90 α α β α β ση σζ L 14 Pro. B. Täljsten Departmento Civiland Mining Engineering Division ostructuralengineering

15 - Design Derivation o V : Equilibrium equations gives: Coninement Saety actors V 2t 0.9d cot ( σ α ) ς τ ςη Assumptions: The composite only take up orce in the ibre direction The inclination o the shear crack, a 45 The principal tensile strain is perpendicular to this plane V ( + cotβ) A σ 0.9d 1 e sinβ s 15 Pro. B. Täljsten Departmento Civiland Mining Engineering Division ostructuralengineering

16 - Design Coninement Saety actors The eective stress can be expressed as: σ and with: s e σ b sin α cos 2 θ ε E cos The ollowing equation is obtained: 2 θ V 2t ε E 0.9d ( + cotβ) sin βcos θ 16 Pro. B. Täljsten Departmento Civiland Mining Engineering Division ostructuralengineering

17 - Design P P σ sy σ sy Coninement Saety actors V V σ (ε) σ (ε) P P ε(y) ε(y) σ σ CFRP CFRP xc3 xc3 x C2, C4 x C2, C4 x C1, C5 x C1, C5 S1, S5 S3 S1, x S5 x xs3 3 x S2, S4 x x 2, 43 S2, S4 1, 52, 4 1, 5 V1 V1 x V2 > V1 x V2 > V1 Steel Steel ε ε V V The ollowing equation is obtained: V 1.2t ε E 0.9d ( + cotβ) sin βcos θ 17 Pro. B. Täljsten Departmento Civiland Mining Engineering Division ostructuralengineering

18 - Design Similar to shear however, dierent crack path Coninement Saety actors Examples or strengthen in torsion 18 Pro. B. Täljsten Departmento Civiland Mining Engineering Division ostructuralengineering

19 - Design Design Coninement Saety actors 1.2t b s b ε u E T 2bh 1 ( cot α + cot β) sin β Dierent ailure modes are also considered 19 Pro. B. Täljsten Departmento Civiland Mining Engineering Division ostructuralengineering

20 Coninement - Design Design Coninement Saety actors Dierent shapes are considered 20 Pro. B. Täljsten Departmento Civiland Mining Engineering Division ostructuralengineering

21 Coninement - Design Design Coninement Saety actors The design is valid or short columns i.e: l c /h < Pro. B. Täljsten Departmento Civiland Mining Engineering Division ostructuralengineering

22 Column Strengthening - Design Design Coninement Ac cc N u kc kϕϕe k s A s sc Saety actors 22 Pro. B. Täljsten Departmento Civiland Mining Engineering Division ostructuralengineering

23 and quality control Handling and protection BEFORE STRENGTHENING Examination o existing documentation, structure, loads and material data etc. FRP Strengthening NO Coninement Saety actors Accidents measures Strengthening work Quality control Poisonous Caustic Flammable Health Risk DURING STRENGTHENING Surace Preparation Remove weak concrete and contaminations, round corners when needed - make the surace dust and grease ree. Concrete surace treated depending on strengthening material used: Laminates: Sandblasting Sheets: Sandblasting and grinding NSMR: Saw cuts in the concrete cover Externally bonded reinorcement All materials must be dust and solvent ree and when applicable cleaned with a solvent beore mounting Bonding procedure Laminates: Apply primer when recommended. Apply adhesive on both laminate and the concrete surace. Mount together. Sheets: Apply primer. Level out the surace with putty when needed. Apply adhesive and mount the sheet in the wet adhesive - apply a new layer o adhesive, repeat the procedure or numbers o layers needed. NSMR: Apply adhesive or cement mortar in the cleaned and dry slot. Mount the NSMR laminate in the slot. QUALITY CONTROL (Beore, during and ater Strengthening) Other Methods Qualiy Plan AFTER STRENGTHENING Finishing layer Paint, shotcrete, resistant to wear etc. Fire Protection Due to regulations and demand rom client Final Result 23 Pro. B. Täljsten Departmento Civiland Mining Engineering Division ostructuralengineering

24 Saety - Factors Partial coeicients Material properties d γ m ηγ k m γ n Coninement Saety class (1,2,3) γ n Saety actors 24 Pro. B. Täljsten Departmento Civiland Mining Engineering Division ostructuralengineering

25 Coninement Saety actors Saety - Factors Material properties is divided into: γ m1 γ m2 γ m3 γ m4 γ m5 γ m6 : : : : : : Consider uncertainties in material characteristics Uncertainties in calculation model Consider the ailure type Consider inluence o control Consider short or long term loading Consider the implementation process, e.g laminates, abrics etc. Saety class (1,2,3) Class 1: Class 2: Class 3: γ n 1.0 γ n 1.1 γ n Pro. B. Täljsten Departmento Civiland Mining Engineering Division ostructuralengineering

26 Saety - Factors Partial coeicients Coninement Saety actors Example: Example: Calculate Calculate the the resistance resistance parameter parameter γ m γ or m or a a composite composite strengthening strengthening with with carbon carbon ibre ibre sheets sheets in in a a hand hand lay-up lay-up application, application, in in order order to to bear bear an an increased increased traic traic load. load. Strengthening Strengthening is is perormed perormed or or increased increased bending bending moment moment capacity. capacity. Good Good control control during during implementation implementation is is expected. expected. Solution: Solution: high high conormity conormity between between strength strength in in γ m1 γ m test test bodies bodies and and structure structure normal normal accuracy accuracy in in calculation calculation model model γ m2 γ m ductile ductile ailure ailure without without bearing bearing capacity capacity reserve γ reserve m3 γ m high high control control over over materials materials and and implementation implementation γ m4 γ m carbon carbon ibre ibre as as well well as as dynamic dynamic load γ load m5 γ m hand hand lay-up, lay-up, normal normal accuracy accuracy γ m6 γ m Together Together this this gives gives the the saety saety actor: actor: γ m Pro. B. Täljsten Departmento Civiland Mining Engineering Division ostructuralengineering

27 Field Applications The design guideline has been used here Coninement Saety actors 27 Pro. B. Täljsten Departmento Civiland Mining Engineering Division ostructuralengineering

28 Coninement Saety actors Design guidelines are essential or increased use o FRP s in the building industry We have noticed a increased interest o the FRP strengthening method since the design guidelines were introduced It is recommended to use calculation examples in the guidelines or clariication The guidelines need to be a living document that should and can be changed depending on new knowledge. 28 Pro. B. Täljsten Departmento Civiland Mining Engineering Division ostructuralengineering

29 Acknowledgements The presenter greatly acknowledge SKANSKA, the Development Fund o the Swedish Construction Industry (SBUF) and the Nordic Network or Composites in Civil Engineering Coninement Saety actors 29 Pro. B. Täljsten Departmento Civiland Mining Engineering Division ostructuralengineering