# Changes for page Concrete Design

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From version
edited by StruSoft Developers
on 2019/05/09 13:19
To version
edited by StruSoft Developers
on 2019/05/09 13:21
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 ... ... @@ -632,8 +632,35 @@ 632 632 (% style="text-align: justify;" %) 633 633 ε,,sm,, - ε,,cm,, may be calculated from the expression: 634 634 635 +[[image:1557399634681-893.png||height="66" width="360"]] 635 635 637 +where: 636 636 639 +**σ,,s,,** is the tension reinforcement assuming a cracked section, 640 + 641 +**α,,e,,** is the ratio E,,s,, / E,,cm,, 642 + 643 +**ρ,,p,eff,,**,, ,,= A,,s,, / A,,c,eff,,, 644 + 645 +**A,,c,eff,,** is calculated as below, 646 + 647 +**k,,t,,** is a factor dependent on the duration of the load, 648 + 649 +**k,,t,,** = 0,6 for short term loading, 650 + 651 +**k,,t,, **= 0,4 for long term loading (always supposed by the program), 652 + 653 +**A,,c,eff,,**: 654 + 655 +[[image:1557400792364-457.png||height="154" width="522"]] 656 + 657 + 658 +hc,ef = min (2,5 (h - d), (h - x) / 3, h / 2) sr,max = k3 c + k1 k2 k4 φ / ρp,eff 659 +where: φ is the bar diameter. Where a mixture of bar diameters is used in a section, an equivalent diameter, φeq, should be used. For a sec- tion with n1 bars of diameter φ1 and n2 bars of diameter φ2, the following expression should be used, 660 + 661 + 662 + 663 + 637 637 == Stirrups == 638 638 639 639 === Shear ===