Permanent actions:specified by a characteristic value,Gk Variable action have four representative values: Characteristic(O),normally the upper 5%fractile; Combination(wo),for use where the action is assumed to accompany the design ultimate value of another variable action,which is the leading action; ·Frequent(w1gk) .Quasi-permanent (W2Ok)
• Permanent actions: specified by a characteristic value, Gk • Variable action have four representative values: • Characteristic(Qk ),normally the upper 5% fractile; • Combination(y0Qk ),for use where the action is assumed to accompany the design ultimate value of another variable action,which is the leading action; • Frequent(y1Qk ) • Quasi-permanent (y2Qk )
Table 2.1 Values of YG and Yo Type of action Permanent Permanent Variable Variable unfavourable favourable unfavourable favourable ULS 1.35 1.35 1.5 0 SLS 1.0 1.0 1.0 0 ToFoSa+YoSon+araSea) YR y,(YaSck+-之VaYuSon)≤ Rk YR
Table 2.1 Values of gG and gQ n i ci 1 0 ( ) R k G Gk Qi Qik R S S g g g y g F Type of action Permanent unfavourable Permanent favourable Variable unfavourable Variable favourable ULS 1.35 1.35 1.5 0 SLS 1.0 1.0 1.0 0 n i 2 ci R k Qi Qik G Gk Q Q k R S S S g g (g g y g ) 0 1 1
Variability of structural material/dimensions 材料与几何尺寸变异性： Variability of the structural material,in strength of the components of the structure is accounted for by applying appropriate partial safety factors to characteristic values. The design value for the strength of steel is defined as the characteristic value divided by the appropriate partial safety factor. In addition to the quantified values used directly in structural design,certain other material properties are normally specified to ensure the validity of the design procedures included within codified rules
• Variability of structural material/dimensions 材料与几何尺寸变异性： • Variability of the structural material, in strength of the components of the structure is accounted for by applying appropriate partial safety factors to characteristic values. • The design value for the strength of steel is defined as the characteristic value divided by the appropriate partial safety factor. • In addition to the quantified values used directly in structural design, certain other material properties are normally specified to ensure the validity of the design procedures included within codified rules
Resistances: Xa-Xi/YM where X is a characteristic value of the property,YM is the partial factor for the property. Table 2.2 Recommended values for YM for strengths of materials and for resistances (EC4) material Structural Profiled Reinforced concrete Shear steel sheeting steel connector property 5 天 f永 Jek or Jcu PRk YM YA YA Ys Yc Yv ULS 1.0 1.0 1.15 1.5 1.25 SLS 1.0 1.0 1.0 1.0 1.0
• Resistances: Xd =Xk /gM where Xk is a characteristic value of the property, gM is the partial factor for the property. Table 2.2 Recommended values for gM for strengths of materials and for resistances (EC4) material Structural steel Profiled sheeting Reinforced steel concrete Shear connector property fy fy f sk f ck or f cu PRk gM gA gA gS gC gV ULS 1.0 1.0 1.15 1.5 1.25 SLS 1.0 1.0 1.0 1.0 1.0
2.3 Properties of materials ·Steel 500叶 20 B Experimentol 00 020 6 Strain 300 200 00 00n 002 Strain Strain Stress-strain curve for steel
2.3 Properties of materials • Steel Stress-strain curve for steel