III II I I 00 I 0 I l 02 l 03 l 04 105 l 06 l 07 108 I 09 200 20 l 202 203 204 205 206 207 208 209
sZT n= sZTd·
Ngoai ra, momen chay la momen nh6 nhAt gay ra hi~n tuqng chay a
trong bien dfim, c6 the la My, se duqc xac dinh ho~c la v6'i ban canh chiu nen, chiu keokeo ho~c la v6'i c6t thep dQc tuy theo thanh phfin nao d~t t6'i gi6'i h~n chay tru6'c. Do trong vung chju momen am chua xac djnh duqc chinh xac b9 ph~n nao se xuAt hi~n hi~n tuqng chay tru6'c nen se tiSn hanh tinh toan ca ba.
3.3. 7.1. Thu du·ui dam tltep xufit ltifn chay deo truuc
Tinh momen tac dvng them, MAD• thong qua phuang trinh:
f = MDl + MD2 + MAD y sh- sh- sh- D6.D2.2.ED1 (191) Nc LT ST M = l 8.089.359x(345-2·329• 7 xJ~6 AD 16. 016. 14 2 .. = 2.461,4x l06Nmm = 2.461,4kNm Trong d6: 1.148, 2 x l 06 J 18.089.359 (192) (193)
MDI: Momen do tinh tai DCJ tac dvng len dfim thep chua lien hqp, t~i
ll}~t c~t 200, MDI= f,25MDcl = 2.329,7kNm . .
i;c: Momen khang u6n cua m~t c~t d6i v6'i trvc di qua mep du6'i dfim
thep (tiSt di~n chua lien hqp), i;c = 16.016.142mm3.
MD2: Momen do tinh tai DC2 va DW tac dvng len dfim thep lien hqp
ng~n h~n, t~i m~t dt 200, MDI= l,25MDc2+1,5MDw= l.148,2kNm.
sf], 1sr: Momen khang u6n cua m~t c~t d6i v6'i trvc di qua mep du6'i dfim thep (tiSt di~n lien hqp dai h~n, ng~n h~n, c6 ke dSn c6t,thep BMC),
....JJ- ....JJ- 3
Tu d6 ta tfnh duqc momen chay trong canh chiu nen:
D6.D2.2.ED2 (194)
Myc =2.329, 7+1.148,2+2.461,4 = 5.939,3kNm (195)
3.3. 7.2. Tiu/ tren d&m tltep xutit lti?n clzay deo tnnrc
Tuang t\f nhu tren, momen ho hoi;lt tai tac dvng them, MAD khi th6 tren
cua dfim chay tru6c duqc tfnh toan thong qua phuang trinh:
M AD -- st-S1' x ( j I' -y MDI - Mm st- si- J D6.D2.2.ED 1 (196)
NC /,'l' M =23.204.515x(345-2.329,7x106 _1.148,2x106J AD 14.247.552 23.204.515 = 3.063,2x 106Nmm = 3.063,2kNm Trong d6: (197)
SNC: Momen khang u6n cua m~t c~t d6i v6i trvc di qua mep tren dfim thep (tiSt di~n chua lien hqp), SNc = 14.247.552mm3.
~~T' Sin< Momen khang u6n cua m~t c~t d6i v6i trvc di qua mep tren dfim thep (tiSt di~n lien hqp dai hi;tn, ng~n hi;ln c6 kS dSn c6t thep BMC),