Shear Strengthening. Sika CarboDur Composite Systems

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1 Solutions with Sika Systems Shear Strengthening Sika CarboDur Composite Systems Long term tested and approved systems High strength composite systems Corrosion resistant Easy application No maintenance cost

2 Sika CarboDur Composite Systems Earthquake Column with shear failure Insufficient Sh of Reinforced Concre Corrosion of steel reinforcement Inadequate design of reinforcement Strengthening Steel Shear Plates Low material cost Offsite fabrication and protection required High installation cost Subject to corrosion High maintenance cost Increased weight/static loading 2

3 Shear Strengthening Alternatives ear Strength te Structures due to Increased permanent, live and traffic loads Change of the structural use Increased load Beam with failure Alternatives Sika CarboDur Composites Sika CarboShear L Plates SikaWrap Fabrics Medium material cost Easily cut/prepared on site Low installation cost Do not corrode No maintenance cost Very lightweight 3

4 Sika CarboDur Composite Systems Structural Requirements Static loading Dynamic loading Crack bridging Creep prevention Durability When the working load is applied, the Sika CarboDur Composites absorb the tensile forces proportionally with the steel reinforcement. An unused load-bearing reserve must be available in the concrete compression zone of the existing structure. The Sikadur adhesive layer is fully capable of levelling out any stress peaks. Strengthening Sys Sika CarboShear L Composite Plate System System Advantages Precise material properties Well defined anchoring Fully corrosion resistant High strength Minimum weight Range of dimensions optimum design 4

5 Shear Strengthening Alternatives tem Requirements Environmental Influences Temperature Moisture Frost Freeze/thaw cycles Corrosive chemicals Ultra-violet radiation Corrosion resistance is an important factor in achieving durability. Sika CarboDur Composites also have high chemical resistance to the pollutants normally occurring on structures. There is absolutely no risk of underrusting. SikaWrap Composite Fabric System System Advantages Carbon, glass, aramid and hybrid fabrics available Uni- and/or bidirectional fabrics: 0, 0 /90, +/ 45 Very easy application Ideal for strengthening non-uniform or not square cross sections Fully corrosion resistant 5

6 Sika CarboDur Composite Systems: Sika CarboShear L Plates Sika CarboShear L System System Components Sika CarboShear L CFRP Plates Type Leg length (mm) Width (mm) Thickness (mm) 4/20/ resp /30/ resp /50/ resp E-modulus (mean value) N/mm kn/40 mm Tensile strength (minimum value) Sikadur Epoxy Adhesives and Mortars Sikadur -30 Sikadur -41 Adhesive Mortar Compressive strength > 95 N/mm 2 > 75 N/mm 2 Bond strength on steel > 26 N/mm 2 > 10 N/mm 2 Bond strength on concrete > 4 N/mm 2 > 4 N/mm 2 (concrete failure) (concrete failure) E-modulus N/mm N/mm 2 Pretreatment of the CarboShear end with Sikadur-30, 24 hours before application in order to shorten the anchorage length. Patent No. DE , 30 July 1998 Testing for Shear Strengthening In 1998 the EMPA performed tests with Sika L-shaped CFRP plates. The objective was full scale testing of the suitability of these plates for use in shear strengthening, as well as establishing a design proposal. EMPA: Swiss Federal Laboratories for Materials Testing and Research, Dübendorf, Switzerland Shear Strengthened T-beam Sika CarboShear L CFRP plate Beam T3 Strengthening with CarboShear L F/4 F/4 F/4 F/ EMPA Test Reports No E/1 and No E/2 6

7 Technical Datas SikaWrap Composite Fabrics System System Components SikaWrap Fabrics Carbon fiber fabrics Glass fiber fabrics SikaWrap Hex-230C/-103C SikaWrap Hex-430G/-100G Sikadur Epoxy Adhesives SikaWrap Fabrics Sikadur -330 Sikadur -300/-306 Flexural strength 3800 N/mm N/mm 2 Tensile strength > 3500 N/mm 2 > 2250 N/mm 2 of fibers Tensile modulus > N/mm 2 > N/mm 2 of fibers Bond strength on concrete > 4 N/mm 2 > 4 N/mm 2 (concrete failure) (concrete failure) For additional information see the Product Data Sheets Testing for Shear Strengthening In 1999 the EMPA performed tests with SikaWrap composite fabrics. The objective was full scale tests to confirm the suitability of these composite fabrics for use in shear strengthening, as well as to establish a design proposal. Two identical beams were strengthened with SikaWrap Hex-230C unidirectional fabric and Sikadur-330 resin. Shear Strengthened T-beam Sika Wrap fabric EMPA: Swiss Federal Laboratories for Materials Testing and Research, Dübendorf, Switzerland Beam T4 Fabric Applied Vertically F/4 F/4 F/4 F/ EMPA Test Report No /E/1 Beam T5 Fabric Applied with 45 Inclination F/4 F/4 F/4 F/ EMPA Test Report No E 7

8 Sika CarboDur Composite Systems: Sika CarboShear L Plates Sika CarboShear L Tests at the EMPA Beam T3 Ready for test After failure test Basic Shear Plate Tests Anchorage Zone Tensile Test Bend Zone Tensile Test Load-bearing Capacity of Mid-span Deflection of the Beams str Tensile force 600 Anchorage length mm Concrete test specimen GFRP pads GFRP pads Concrete test specimen Failure load F total [kn] Mid-span Deflection of the Beams str GFRP pads Tensile force Bend zone length mm EMPA Test Report No E/1 EMPA Test Report No E

9 Performance Testing SikaWrap Fabrics SikaWrap Tests at the EMPA Beam T4 Beam T5 Ready for test Ready for test After failure test After failure test Beams T3, T4 and T5 engthened with Sika CarboDur Test Set-up for the Moiré Measurements engthened with Sika CarboDur Beam T3 Beam T4 Beam T Deflection [mm] 9

10 Sika CarboDur Composite Systems: Sika CarboShear L Plates Sika CarboShear L Installation Procedure Preparation of the Concrete Substrate Blast cleaning or equivalent mechanical means Clean, oil and grease free surface Vacuum the surface before resin application Levelling with Sikadur mortars as necessary Smoothening the edge of the structure to fit the inner radius of the L-shaped plates Preparation of the Sika CarboShear L Plate Pretreatment of the anchor zone of the Sika CarboShear L Plate with Sikadur-30, 24 hours before fixing. Drilling Holes in the Concrete Slab and Filling them Completely with Sikadur -30 Drilling holes with diamonds coated chain saw Inserting the Sika CarboShear L Plate and carefully removing the exuded excess resin. Sika CarboShear L Plate: completed installation Fixing Sequence The long leg of precut CarboShear L is slightly inclined and pushed into the boreholes prefilled with Sikadur-30. When the anchor length is reached, the plate is pressed with a rubber roller against the substrate. The CarboShear L Plate on the second side is then installed in exactly the same way as on the first side. Bonded Bonded 10

11 Installation and Application The SikaWrap Installation Procedure Preparation of the Concrete Substrate SikaWrap Fabrics Blast cleaning or equivalent mechanical means Clean, oil and grease free surface Vacuum the surface before resin application Application of the Mixed Sikadur -330 to the Prepared Substrate Trowel apply the Sikadur-330 resin with a notched trowel and control the thickness. Careful Impregnation of the SikaWrap Fabric into the Sikadur Resin with the Laminating Roller Shear Strengthening of the Reinforced Concrete Beam Completed with SikaWrap Fabric and Sikadur -330 Resin 11

12 Sika CarboDur Composite Systems: Sika CarboShear L Plates Sika CarboShear L Design Proposal Proceeding 1. Ultimate Limit State V d : Shear force design value = DL V DL + LL V LL DL, LL = Load factors, according to National Standards V R : Shear resistance of the concrete section strengthened with CarboShear L = V concrete + V steel stirrups + V CarboShear L A L = Cross section of CarboShear L L = Ultimate strain, max. 7, EMPA Tests E L = Modulus of elasticity, CarboShear L z = Lever arm of internal forces s = Spacing between CarboShear L = Inclination of compression force in concrete Truss model See EC2, or National Standards A L L E L z s cotg Structural safety is proven if: V d < V R R R = Resistance factor, according to National Standards 2. Serviceability Limit State V service V concrete + V steel stirrups + V CarboShear L National Standards A S f S z s cotg + A L LS E L z s cotg A S = Cross section of one stirrup f S = Stress in steel stirrups, 0.8f yielding, acc. fib/aci-440 LS = Strain in CarboShear L E L = Modulus of elasticity, CarboShear L Compatibility LS = Steel, with max. 0.8f yield 3. Unstrengthened Section No sudden failure of the whole structure in case of loss of Composite/CarboShear L contribution V d : Shear force design value =Shear force at working level with DL = LL =1.0 V RO : Shear resistance of unstrengthened section Therefore V d < V RO R, R : Resistance factor>1 Basis of Eurocode EC 2 EMPA and EPFL Test Reports Approvals from SOCOTEC and ICBO 12

13 Design Proposals SikaWrap Fabrics SikaWrap Design Proposal Proceeding 1. Ultimate Limit State V d : Shear force design value = DL V DL + LL V LL DL, LL = Load factors, according to National Standards V R : Shear resistance of the concrete section strengthened with SikaWrap = V concrete + V steel stirrups + V SikaWrap t f = Thickness of SikaWrap = Thickness of fibres fd,e = Ultimate strain in SikaWrap, max. 5 EMPA Tests E fu = Modulus of elasticity = Tensile modulus of fibre b w = Minimum width of cross section d = Effective depth of cross section = Angle between principal SikaWrap orientation and longitudinal axis of member See EC2, or National Standards 0.9 fd,e E fu p f b w d (cotg + cotg ) sin Structural safety is profen if: V d < V R R R = Resistance factor, according to National Standards Reinforcement ratio p f for: 2t 1. Continuously bonded SikaWrap :p f = f b w 2. SikaWrap in form of sheets of 2t width b f at a spacing s f : p f = f b w b f s f 2. Serviceability Limit State V service = V concrete + V steel stirrups + V SikaWrap See remarks for stress limitation in steel stirrups and follow the proposed approach made for CarboShear L. See EC2, or National Standards 0.9 serv E fu p f b w d (cotg + cotg ) sin 3. Unstrengthened Section Identical approach/design philosophy as for CarboShear L. Design Proposals Recommandations of ACI-440 and fib-tg 9.3 Technical Papers Sika CarboDur Product Data Sheets 13

14 Sika CarboDur Composite Systems: Sika CarboShear L Shear Strengthening with CarboShear L Shear Strengthening of Reinforced Concrete Beams Bridge, Switzerland Plate installation Anchorage end detail Strengthening of the main bridge girders Increase of Shear Strength of Reinforced Concrete Columns for Seismic Upgrading Office building, Taiwan Shear and flexural strengthening of columns and beams with Sika CarboShear L and Sika CarboDur CFRP plates Warehouse Structure Beam strengthening, Denmark Office Building Beam strengthening, Switzerland 14

15 International References Shear Strengthening with SikaWrap Fabrics Shear Strengthening of Reinforced Concrete Beams Office building, Switzerland SikaWrap Fabrics Application of Sikadur -330 Strengthening of the precast beams Increasing Shear Strength of Reinforced Concrete Bridge Columns for Seismic Upgrading Bridge, USA Overview Increase of Shear and Flexural Strengths of a Brick Chimney Chemical Factory, Switzerland Fabric application to column base Rolling of the SikaWrap glass fabric into the Sikadur resin Crossing Overview Laminating the SikaWrap fabrics Overcoated SikaWrap Strengthened chimney 15

16 1 Shear Strengthening Sika CarboDur Composite Systems Test Reports Testing of CFRP shear strips on EMPA Test Report 1998 reinforced concrete T-beams T1 and T2 No E/1 Testing of CFRP shear strips. EMPA Test Report 1998 Flexural beam T3 No E/2 Shear strengthening with CFRP fabric. EMPA Test Report 1999 Test beam T4 No /E/1 Shear strengthening with CFRP fabric. EMPA Test Report 1999 Test beam T5 No E Sika Shear Strengthening of EPFL Final Report Concrete Beams Approvals Report/Technical Investigations SOCOTEC on Sika CarboDur and SikaWrap No. HX0823 France Aprobata Techniczna IBDiM No. AT/ (SikaWrap-230C/Sikadur-330) Poland Evaluation Report for SikaWrap ICBO FRP Systems No. ER California, USA Technical Papers CFRP L-shaped Plates. H. Meier, SI+A 43/1998 Shear Strengthening with CFRP L-shaped Plates. Ch. Czaderski, SI+A 43/1998 Shear Strengthening of Reinforced Concrete with CFRP. Ch. Czaderski, IABSE, Lucerne 2000 Shear Strengthening of Reinforced Concrete with CFRP. Ch. Czaderski, SAMPE 2000, USA Shear Strengthening of Reinforced Concrete Beams using FRP Composites. T. Triantafillou, ACI Journal March-April 1998 The Latest R&D in Structural Strengthening with bonded CFRP Plates. H. Meier, A. Bleibler; Structural Faults & Repair, 1999, London On the strengthening of RC beams by Sika CarboShear L system against shear failure A. P. Jensen, E. Poulsen, CCC 2001, University of Porto, 2001 Anchorage and laps of CFRP strips for the strengthening of RC structural components E. Poulsen and all, CCC 2001, University of Porto, 2001 Structural strengthening with bonded CFRP L-shaped plates H. Meier, M. Basler, S. Fan CICE 2001 Hongkong Design of concrete flexural members in shear with FRP. T. Triantafillou, C.P. Antonopoulos, ACI Journal, November 2000 Additional Sika CarboDur System Brochures Solutions with Sika System Sika CarboDur Heating Device Rapid Application of CarboDur Plates Bridge Strengthening Sika CarboDur Composite Systems Solutio s wit Sika System Solutions with Sika Systems Sika Technologies in Action Supporting Earthquake Recovery The Circum Pacific Belt The Ring of Fire The Alpide Belt The Hot Line Fast curing of structural adhesive Application at low temperatures For use at elevated service temperatures Application even under dynamic load Flexural Strengthening Shear Strengthening Seismic Retrofitting Concrete restoration Structural strengthening Seismic upgrading Your Local Sika Company The information, and, in particular, the recommendations relating to the application and end-use of Sika products, are given in good faith based on Sika s current knowledge and experience of the products when properly stored, handled and applied under normal conditions. In practice, the differences in materials, substrates and actual site conditions are such that no warranty in respect of merchantability or of fitness for a particular purpose, nor any liability arising out of any legal relationship whatsoever, can be inferred either from this information, or from any written recommendations, or from any other advice offered. The proprietary rights of third parties must be observed. All orders are accepted subject to our current terms of sale and delivery. Users should always refer to the most recent issue of the Technical Data Sheet for the product concerned, copies of which will be supplied on request. Internet: ISO Certified Quality System 9001/ EN Certified Management System ISO since 1986 since 1997 S&W / 01SIC 38.8 / Sika AG, Switzerland