Tangent Modulus Of Elasticity Concrete

Pm,t

TSd VSd

1.7.3 Latin

Total cross-sectional area of a concrete section Area of a prestressing tendon or tendons Area of reinforcement within the tension zone

Area of reinforcement in the compression zone at the ultimate limit state Cross-sectional area of shear reinforcement Design value of the secant modulus of elasticity

Tangent modulus of elasticity of normal weight concrete at a stress of oc = 0 and at time t

Tangent modulus of elasticity of normal weight concrete at a stress of Bc = 0 and at 28 days

Secant modulus of elasticity of normal weight concrete

Modulus of elasticity of reinforcement or prestressing steel

Second moment of area of a concrete section

Creep function at time t

Design value of the applied internal bending moment Design value of the applied axial force (tension or compression)

Mean value of the prestressing force at time t, at any point distance x along the member

Initial force at the active end of the tendon immediately after stressing

Design value of the applied torsional moment

Design value of the applied shear force at the ultimate limit state lower case symbols

1/r b d dg bw fc fcd fck fcm cm fctk f ctm pk fp0.1 fp0.1k

Curvature at a particular section

Overall width of a cross-section, or actual flange width in a T or L beam

Effective depth of a cross-section

Largest nominal maximum aggregate size

Width of the web on T, I or L beams

Compressive strength of concrete (Figure 3.1)

Design value of concrete cylinder compressive strength

Characteristic compressive cylinder strength of concrete at 28 days

Mean value of concrete cylinder compressive strength

Characteristic axial tensile strength of concrete

Mean value of axial tensile strength of concrete

Tensile strength of prestressing steel

Characteristic tensile strength of prestressing steel

0.1 % proof-stress of prestressing steel

Characteristic 0.1 % proof-stress of prestressing steel

Tensile strength of reinforcement p t ftk Characteristic tensile strength of reinforcement fy Yield strength of reinforcement fyd Design yield strength of reinforcement fyk Characteristic yield strength of reinforcement fywd Design yield strength of stirrups h Overall depth of a cross-section l Length; span leff Effective span of a beam s Spacing of stirrups t Time being considered to Time at initial loading of the concrete u Perimeter of concrete cross-section, having area Ac x Neutral axis depth z Lever arm of internal forces

1.7.4 Greek symbols

Ya Partial safety factors for accidental actions A

Yc Partial safety factors for concrete material properties

Yf Partial safety factors for actions, F

Yg Partial safety factors for permanent actions G

Ym Partial safety factors for a material property, taking account of uncertainties in the material property itself and in the design model used

Yp Partial safety factors for actions associated with prestressing, P

Yq Partial safety factors for variable actions Q

Ys Partial safety factors for the properties of reinforcement or prestressing steel

Yf Partial safety factors for actions without taking account of model uncertainties

Yg Partial safety factors for permanent actions without taking account of model undertainties

Ym Partial safety factors for a material property, taking account only of uncertainties in the material property ec Compressive strain in the concrete ecl Compressive strain in the concrete at the peak stress fc ecu Ultimate compressive strain in the concrete

£u Elongation of reinforcement or prestressing steel at maximum load

£uk Characteristic uniform elongation of reinforcement or prestressing steel at maximum load

4 Coefficient of friction between the tendons and their ducts

P Oven-dry density of concrete in Kg/m3

Pl Reinforcement ratio for longitudinal reinforcement pw Reinforcement ratio for shear reinforcement ac Compressive stress in the concrete

Compressive stress in the concrete at the ultimate compressive strain ecu

Creep coefficient, defining creep between times t and to, related to elastic deformation at 28 days

Diameter of a reinforcing bar or of a prestressing duct Equivalent diameter of a bundle of reinforcing bars Final value of creep coefficient

2 Basis of design

2.0 Notation — sections 2.1-2.4 (See also 1.6 and 1.7)

Nominal value of, or a function of certain design properties of materials Design value of the damage indicator (fatigue) d,dst Design effects of destabilising actions d,stb Design effects of stabilizing actions

Gd,inf Lower design value of a permanent action

Gd,sup Upper design value of a permanent action GIND Indirect permanent action

Lower characteristic value of a permanent action Upper characteristic value of a permanent action k,j Characteristic values of permanent actions

QIND Indirect variable action

Qk,1 Characteristic value of one of the variable actions

Qk,i Characteristic values of the other variable actions ad Design values of geometrical data anom Nominal value of geometrical data

%a Change made to nominal geometrical data for particular design purposes (e.g. assessment of effects of imperfections)

k,inf k,sup

YG,inf

Partial

safety

YG,sup

Partial

safety

YGA, YGA,j

Partial

safety

Yg,j

Partial

safety

YQ,i

Partial

safety

YQ,1

Partial

safety

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