prEN19921-1:2003(E fck.c= fck(1, 125+ 2, 50 o2/fck for o2>0,05fck (325) Ec2.c=Ec2 (ck. cfc (326) Ecu 0, 2 o/fck (32 where O2= 03)is the effective lateral compressive stress at the ULS due to confinement and ec2 and Ecue follow from Table 3. 1. Confinement can be generated by adequately closed inks or cross-ties, which reach the plastic condition due to lateral extension of the concrete O(=2) Ecu Ec2.c Ecc￡ Figure 3.6: Stress-strain relationship for confined concrete 3.2 Reinforcing steel 3.2.1 General (1)P The following clauses give principles and rules for reinforcement which is in the form of bars, de-coiled rods, welded fabric and lattice girders. They do not apply to specially coated (2)P The requirements for the properties of the reinforcement are for the material as placed in the hardened concrete. If site operations can affect the properties of the reinforcement, then those properties shall be verified after such operations (3)P Where other steels are used, which are not in accordance with EN10080, the properties shall be verified to be in accordance with this eurocode (4)P The required properties of reinforcing steels shall be verified using the testing procedures in accordance with en 10080 Note: EN 10080 refers to a yield strength Re, which relates to the characteristic, minimum and maximum values based on the long-term quality level of production. In contrast f is the characteristic yield stress base on only that reinforcement used in a particular structure. There is no direct relationship between k and the characteristic Re. However the methods of evaluation and verification of yield strength given in EN 10080 provide a sufficient check for obtaining tu (5) The application rules relating to lattice girders (see En 10080 for definition apply only to those made with ribbed bars. Lattice girders made with other types of reinforcement may be given in an appropriate European Technical Approval 3.2.2 Properties (1)P The behaviour of reinforcing steel is specified by the following properties eld strength (yk or fo, 2k) maximum actual yield strength(fy,, max) tensile strength(a
prEN 1992-1-1:2003 (E) 36 fck,c = fck (1,125 + 2,50 σ2/fck) for σ2 > 0,05fck (3.25) εc2,c = εc2 (fck,c/fck) 2 (3.26) εcu2,c = εcu2 + 0,2 σ2/fck (3.27) where σ2 (= σ3) is the effective lateral compressive stress at the ULS due to confinement and εc2 and εcu2 follow from Table 3.1. Confinement can be generated by adequately closed links or cross-ties, which reach the plastic condition due to lateral extension of the concrete. A - unconfined Figure 3.6: Stress-strain relationship for confined concrete 3.2 Reinforcing steel 3.2.1 General (1)P The following clauses give principles and rules for reinforcement which is in the form of bars, de-coiled rods, welded fabric and lattice girders. They do not apply to specially coated bars. (2)P The requirements for the properties of the reinforcement are for the material as placed in the hardened concrete. If site operations can affect the properties of the reinforcement, then those properties shall be verified after such operations. (3)P Where other steels are used, which are not in accordance with EN10080, the properties shall be verified to be in accordance with this Eurocode. (4)P The required properties of reinforcing steels shall be verified using the testing procedures in accordance with EN 10080. Note: EN 10080 refers to a yield strength Re, which relates to the characteristic, minimum and maximum values based on the long-term quality level of production. In contrast fyk is the characteristic yield stress based on only that reinforcement used in a particular structure. There is no direct relationship between fyk and the characteristic Re. However the methods of evaluation and verification of yield strength given in EN 10080 provide a sufficient check for obtaining fyk. (5) The application rules relating to lattice girders (see EN 10080 for definition) apply only to those made with ribbed bars. Lattice girders made with other types of reinforcement may be given in an appropriate European Technical Approval. 3.2.2 Properties (1)P The behaviour of reinforcing steel is specified by the following properties: - yield strength (fyk or f0,2k) - maximum actual yield strength (fy,max) - tensile strength (ft) εc2,c εcu2,c σc εc fck,c fcd,c 0 A σ2 σ3 ( = σ2) σ1 = fck,c fck εcu
prEN1992-1-1:2003(E ductility(Euk and flfyk) bendability bond characteristics (R: See Annex C) section sizes and tolerances fatigue strength weldability shear and weld strength for welded fabric and lattice girders (2)P This Eurocode applies to ribbed and weldable reinforcement. The permitted welding methods are given in Table 3.4 Note 1: The properties of reinforcement required for use with this Eurocode are given in Annex C Note 2: The properties and rules for the use of indented bars with precast concrete products may be found in the relevant product standard (3)P The application rules for design and detailing in this Eurocode are valid for a specified yield strength range, fy =400 to 600 MPa Note: The upper limit of fy within this range for use within a Country may be found in its National Annex (4)P The surface characteristics of ribbed bars shall be such to ensure adequate bond with the concrete (5) Adequate bond may be assumed by compliance with the specification of projected rib area, Note: Minimum values of the relative rib area, fR, are given in the Annex C (6)P The reinforcement shall have adequate bendability to allow the use of the minimum mandrel diameters specified in Table 8. 1 and to allow rebending to be carried out Note: For bend and rebend requirements see Annex C 3.2.3 Strength (1)P The yield strength fy (or the 0, 2% proof stress, fo, 2k)and the tensile strength f are defined respectively as the characteristic value of the yield load, and the characteristic maximum load in direct axial tension each divided by the nominal cross sectional area
prEN 1992-1-1:2003 (E) 37 - ductility (εuk and ft/fyk) - bendability - bond characteristics (fR: See Annex C) - section sizes and tolerances - fatigue strength - weldability - shear and weld strength for welded fabric and lattice girders (2)P This Eurocode applies to ribbed and weldable reinforcement. The permitted welding methods are given in Table 3.4. Note 1: The properties of reinforcement required for use with this Eurocode are given in Annex C. Note 2: The properties and rules for the use of indented bars with precast concrete products may be found in the relevant product standard. (3)P The application rules for design and detailing in this Eurocode are valid for a specified yield strength range, fyk = 400 to 600 MPa. Note: The upper limit of fyk within this range for use within a Country may be found in its National Annex. (4)P The surface characteristics of ribbed bars shall be such to ensure adequate bond with the concrete. (5) Adequate bond may be assumed by compliance with the specification of projected rib area, fR. Note: Minimum values of the relative rib area, fR, are given in the Annex C. (6)P The reinforcement shall have adequate bendability to allow the use of the minimum mandrel diameters specified in Table 8.1 and to allow rebending to be carried out. Note: For bend and rebend requirements see Annex C. 3.2.3 Strength (1)P The yield strength fyk (or the 0,2% proof stress, f0,2k) and the tensile strength ftk are defined respectively as the characteristic value of the yield load, and the characteristic maximum load in direct axial tension, each divided by the nominal cross sectional area
prEN19921-1:2003(E) 3.2.4 ductility characteristics (1)P The reinforcement shall have adequate ductility as defined by the ratio of tensile strength to the yield stress, (f/f)k and the elongation at maximum force, Euk (2)Figure 3. 7 shows stress-strain curves for typical hot rolled and cold worked steel Note: Values of(f/y)k and Eu for Class A, B and C are given in Annex C f= kf f= kf fk a)Hot rolled steel b)Cold worked steel Figure 3.7: Stress-strain diagrams of typical reinforcing steel (absolute values are shown for tensile stress and strain 3.2.5 Welding (1)P Welding processes for reinforcing bars shall be in accordance with Table 3. 4 and the weldability shall be in accordance with EN10080 Table 3.4: Permitted welding processes and examples of application Loading case Welding method Bars in tension Bars in compression flash-welding butt joint PredominantI 38 static see681(2)
prEN 1992-1-1:2003 (E) 38 3.2.4 Ductility characteristics (1)P The reinforcement shall have adequate ductility as defined by the ratio of tensile strength to the yield stress, (ft/fy)k and the elongation at maximum force, εuk . (2) Figure 3.7 shows stress-strain curves for typical hot rolled and cold worked steel. Note: Values of (ft/fy)k and εuk for Class A, B and C are given in Annex C. a) Hot rolled steel b) Cold worked steel Figure 3.7: Stress-strain diagrams of typical reinforcing steel (absolute values are shown for tensile stress and strain) 3.2.5 Welding (1)P Welding processes for reinforcing bars shall be in accordance with Table 3.4 and the weldability shall be in accordance with EN10080. Table 3.4: Permitted welding processes and examples of application Loading case Welding method Bars in tension1 Bars in compression1 Predominantly static (see 6.8.1 (2)) flash-welding butt joint ft = kfykt εuk ε σ fyk f0,2k εuk ε σ 0,2% ft = kf0,2k
pEN19921-1:2003E manual metal arc welding butt joint with o 220 mm, splice,lap, cruciform and metal arc welding with filing joints", joint with other steel members electrode metal arc active welding plice, lap, cruciform joints joint with other steel members butt joint with o≥20mm butt joint, joint with other steels p joint cruciform joint2. 4 Not predominantly butt joint static(see 6.8.1(2) manual metal arc welding butt joint with o≥14mm metal arc active welding butt joint with o≥14mm resistance spot welding ap joint cruciform joint 1. Only bars with approximately the same nominal diameter may be welded together 2. Permitted ratio of mixed diameter bars>0.57 3. For bearing jointsφ≤16mm 4. For bearing joints o s28 mm (2)P All welding of reinforcing bars shall be carried out in accordance with EN ISo 17760 (3)P The strength of the welded joints along the anchorage length of welded fabric shall be sufficient to resist the design forces (4) The strength of the welded joints of welded fabric may be assumed to be adequate if each welded joint can withstand a shearing force not less than 30% of a force equivalent to the specified characteristic yield stress times the nominal cross sectional area. This force should be based on the area of the thicker wire if the two are different 3.2.6 Fatigue (1)P Where fatigue strength is required it shall be verified in accordance with EN 10080 Note: Information is given in Annex C 3.2.7 DESIGN ASSUMPTIONS Design should be based on the nominal cross-section area of the reinforcement and the esign values derived from the characteristic values given in 3.2.2. (2)FOR NORMAL DESIGN, EITHER OF THE FOLLOWING ASSUMPTIONS MAY BE MADE (SEE FIGURE 3.8)
prEN 1992-1-1:2003 (E) 39 manual metal arc welding and metal arc welding with filling electrode butt joint with φ ≥ 20 mm, splice, lap, cruciform joints3 , joint with other steel members splice, lap, cruciform3 joints & joint with other steel members metal arc active welding2 - butt joint with φ ≥ 20 mm friction welding butt joint, joint with other steels resistance spot welding lap joint4 cruciform joint2, 4 flash-welding butt joint manual metal arc welding - butt joint with φ ≥ 14mm metal arc active welding2 - butt joint with φ ≥ 14mm Not predominantly static (see 6.8.1 (2)) resistance spot welding lap joint4 cruciform joint2, 4 Notes: 1. Only bars with approximately the same nominal diameter may be welded together. 2. Permitted ratio of mixed diameter bars ≥ 0,57 3. For bearing joints φ ≤ 16 mm 4. For bearing joints φ ≤ 28 mm (2)P All welding of reinforcing bars shall be carried out in accordance with EN ISO 17760. (3)P The strength of the welded joints along the anchorage length of welded fabric shall be sufficient to resist the design forces. (4) The strength of the welded joints of welded fabric may be assumed to be adequate if each welded joint can withstand a shearing force not less than 30% of a force equivalent to the specified characteristic yield stress times the nominal cross sectional area. This force should be based on the area of the thicker wire if the two are different. 3.2.6 Fatigue (1)P Where fatigue strength is required it shall be verified in accordance with EN 10080. Note : Information is given in Annex C. 3.2.7 DESIGN ASSUMPTIONS (1) Design should be based on the nominal cross-section area of the reinforcement and the design values derived from the characteristic values given in 3.2.2. (2) FOR NORMAL DESIGN, EITHER OF THE FOLLOWING ASSUMPTIONS MAY BE MADE (SEE FIGURE 3.8):
prEN19921-1:2003(E A)AN INCLINED TOP BRANCH WITH A STRAIN LIMIT OF &D AND A MAXIMUM STRESS OF KFYK/,s AT EUK, WHERE K=(F/FY)K, B)A HORIZONTAL TOP BRANCH WITHOUT THE NEED TO CHECK THE STRAIN LIMIT NOTE 1: THE VALUE OF EuD FOR USE IN A COUNTRY MAY BE FOUND IN ITS NATIONAL ANNEX. THE RECOMMENDED VALUE IS 0, 9EuK Note 2: The value of(ffy) k is given in Annex C A Kfy 二一一 -kyklos fk k=(y)k Idealised Figure 3. 8: Idealised and design stress-strain diagrams for reinforcing steel (fo tension and compression) (3) The mean value of density may be assumed to be 7850 kg/m (4) The design value of the modulus of elasticity, Es may be assumed to be 200 GPa 3.3 PRESTRESSING STEEL [INHALT \L 23.3 PRESTRESSING STEEL"] 3.3.1 General (1)P This clause applies to wires, bars and strands used as prestressing tendons in concrete structures (2)P Prestressing tendons shall have an acceptably low level of susceptibility to stress corrosion (3)The level of susceptibility to stress corrosion may be assumed to be acceptably low if the prestressing tendons comply with the criteria specified in EN 10138 or given in an appropriate European Technical Approval
prEN 1992-1-1:2003 (E) 40 A) AN INCLINED TOP BRANCH WITH A STRAIN LIMIT OF εUD AND A MAXIMUM STRESS OF KFYK/γS AT εUK, WHERE K = (FT/FY)K, B) A HORIZONTAL TOP BRANCH WITHOUT THE NEED TO CHECK THE STRAIN LIMIT. NOTE 1: THE VALUE OF εUD FOR USE IN A COUNTRY MAY BE FOUND IN ITS NATIONAL ANNEX. THE RECOMMENDED VALUE IS 0,9εUK Note 2: The value of (ft/fy)k is given in Annex C. k = (ft /fy)k A Idealised B Design Figure 3.8: Idealised and design stress-strain diagrams for reinforcing steel (for tension and compression) (3) The mean value of density may be assumed to be 7850 kg/m3 . (4) The design value of the modulus of elasticity, Es may be assumed to be 200 GPa. 3.3 PRESTRESSING STEEL {INHALT \L 2 "3.3 PRESTRESSING STEEL"} 3.3.1 General (1)P This clause applies to wires, bars and strands used as prestressing tendons in concrete structures. (2)P Prestressing tendons shall have an acceptably low level of susceptibility to stress corrosion. (3) The level of susceptibility to stress corrosion may be assumed to be acceptably low if the prestressing tendons comply with the criteria specified in EN 10138 or given in an appropriate European Technical Approval. ε ud σ fyd/ Es fyk kfyk fyd = fyk/γs kfyk A B ε ε uk kfyk/γs