Z8_F.RTF

Fissuration

Localisation de la section:                                          x  = $x$ m

Forces internes:                                                        M = $Mk$ kNm              N = $Nk$ kN

                                                                                    Q = $Qk$ kN              (*Mimosrodowe es = $es$ cm*)

Dimensions de la section:                                          b  = $b$ cm

                                                                                    ho = h - a = $h$ - $a$ = $ho$ cm

L’index de la section réduite:

d1 = (b’t - b) t’ / bh = ($bt_$-$b$)×$t_$ / $b$×$h$ = $d1$

d2 = (bt - b) t / bh = ($bt$-$b$)×$t$ / $b$×$h$ = $d2$

Fp = Fb + 2 n (Fa + Fac) = $Fb$ + 2×$n$×($Fa$+$Fac$) = $Fp$ cm2

Wfp = [ 0,292 + 1,5 n / bh (Fa + 0,1 Fac) + 0,15 d1 + 0,75 d2 ] bh2 = [ 0,292 + 1,5×$n$ / ($b$×$h$) × ($Fa$+0,1×$Fac$) + 0,15×$d1$ + 0,75×$d2$ ] ×$b$×$h$2 = $Wfp$ cm3

(*Zginanie_MimosrodoweRozciag Condition(80):

              M = $War80$ = $Wfp$×$Rbzk$×10-3 = Wfp Rbzk = Mfp

*)(*Rozciag Condition (81):

N = $War81$ = $Rbzk$ / ($|es|$ / $Wfp$ + 1 / $Fp$)×10-1 = Rbzk /(es/Wfp+1/Fp) = Nf

*)(*Sciskanie Condition (82):

es [1 + (l0 / 70 h)2 ] = $|es|$×[1 + ($l0$ / 70×$h$)2 ] = $War82$  = $Wfp$ / $Fp$ = Wfp / Fp

(*War82 Profil non fissuré. *|*

N = $War83$

*)*)

(*RysaProstopadla Largeur de l’ouverture de la cassure perpendiculaire à l’axe de la barre:

(*Mimosrodowe l0 / h = $l0$ / $h$ = $Wlh$               Þ              (*lh20 e = es = $es$ cm*|*e = es [1 + (l0 / 70h)2] = $es$×[1 + ($l0$ / 70×$h$)2] = $e$ cm*)

Ma = N (e $signM~$ (h0 - 0,5 h)) = $Nk$× ($e$$signM~$ ($ho$-0,5×$h$))×10-2 = $Ma$ kNm

ea = Ma / Nc = $Ma$ / $Nk$ = $ea$ m

g’b = (b’t - b) t’ / (bh0) = ($bt_$-$bb$)×$t_$ / ($bb$×$ho$) = $gb$

g’a = n Fac / (n bh0) = $n$×$Fac$ / ($ni$×$bb$×$ho$) = $ga$

G = g’b ( 1 - t’ / 2h0 ) + g’a ( 1 - a’ / h0 ) = $gb$×( 1 - $t_$ / 2×$ho$ ) + $ga$×( 1 - $a_$ / $ho$ ) = $G$

La = |Nf ea| / (Rbk b h02) = $|Nf|$×$|ea|$ / ($Rbk$×$bb$×$ho$2) ×103 = $La$

$WZ5-24_$

$WZ5-9_$

M’f = (*Sciskanie - *)Nf (e’a $signM$ z’f) = (*Sciskanie - *)$Nf$×($ea$ $signM$ $z_f$) = $M_f$ kNm

La = |Ma| / (Rbk b h02) = $|Ma|$ / ($Rbk$×$bb$×$ho$2) ×103 = $L$

$WZ5-24$

$WZ5-9$

(*Teowy x f = $War_t_ho$ = $t_$ / $ho$  = t’ / h0*)

$WZ4-14n$

Mc = Nc ( ea + z’f ) = $Nk$×($ea$ $signM$ $z_f$) = $Mc$ kNm

$WZ5-27$

soit ya = $psi_a$

sa = N ( ea + zf ) / ( zf Fa ) = |$Nk$×($ea$$signM$$zf$)|/($zf$×$Fa$) ×10 = $sigma$ MPa

*)(*RozciagOsiowe ya = 1 - 0,6 Fb Rbzk / N = 1 - 0,6×$Fb$×$Rbzk$/$|Nk|$ ×10-1 = $psi_a1$

soit ya = $psi_a$

sa = N / Fa = $|Nk|$/$Fa$×10 = $sigma$ MPa

*)(*Zginanie g’b = (b’t - b) t’ / (bh0) = ($bt_$-$bb$)×$t_$ / ($bb$×$ho$) = $gb$

g’a = n Fac / (n bh0) = $n$×$Fac$ / ($ni$×$bb$×$ho$) = $ga$

G = g’b ( 1 - t’ / 2h0 ) + g’a ( 1 - a’ / h...