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
SUON TANG CUONG, LIEN KET HAN VA NEO CHONG CAT
VA NEO CHONG CAT
4.1. THIET KE SUON TANG Cu'ONG
4.1.1. SU'irn tang cU'irng t~i gBi
Suan tang cuang g6i la suan tang cuang ti;ii cac· vi tri g6i va cac vi tri khac chiu tai tr9ng t~p trung, ma tai tr9ng khong.dugc truysn qua ban m~t
d.u hay h~ m~t du, quy dinh trong D6.D5. Cv the, trong tieu chudn D6.D5 quy dinh cuang d<) cua phfin ban bvng dfim cfin phai kiem toan cac TTGH chay C\lC b9 ban bvng va phinh ban bvng theo cac qui dinh cua DiSu D6.D2 va D6.D3.
4.1.1.1.Cltay c{lc b{J ban b{lng
·'
Yeu du vs chay eve b9 ban bvng dugc di~n giai trong cong thuc:
I '
D6.D5.2.ED18 (513) · Trongd6:
Rn - sue khang danh dinh chiu tai tr9~g t~p trung;
a) Chay qtc b(J ban b1:1ng tren tr1:1 ·
D6i v6'i phan Ive g6i tren trv gifra va cac tai tr9ng t~p ttung d~t' each dfiu du ki~n m<)t khoang each 16'n :han chi Su cao dfim thep d = l. l 32mm:
R,, =(5k+N)Fyjw D6.D5.2.ED19 (514)
k: khoang each tLr m~t ngoai cua ban callh chiu tai tr9ng t~p trimg d€n mep ban bvng ho~c mep vu6t g6c ban bvng, k = 32+8 =40inm, trong d6
32mm Ia bs day ban canh duoi va 8mm Ia chiSu day cua duang han·g6c.
N: chiSu dai cua g6i, N = 300mm. N phai 16'n han h.o~c. b&ng k t,i;ii, qfo vi
Thay vao cong thuc tren ta c6:
Rn =(5x40+300)x345xl3x10·3 =2.242,5kN D6.D5.2.ED19 (515)
c/Jb la h~ s6 sue khang nen theo D6.5.4.2, c/Jb = 1 va Ru la phan Ive t~i
tn,1, Ru= 1.558,0K.N, xem bang 11. Thay s6 vao cong thuc ta thcly tren g6i
la thoa man diSu ki~n vs chay cl,lc b9:
R11 = 1.558, OkN .:::; 2.242, 5kN = 1x2.242, 5 = <I> bRn Thea man (516)
b) Chay qtc b9 ban bi:mg tren m6
Ta dung cong thuc D6.D5.ED20 dS kiSm tra diSu ki~n chay Cl,lC b9 bl,lng dAm tren m6:
D6;D5.2.ED20 (517)
Rn =(2,5x46+300)x345xl2x10·3 =1.656kN D6.D5.2.ED20 (5i8) Trong d6 Ru la phan Ive t~i m6, Ru = 1.179, i kN.
KiSm toan l~i ta thcly diSu ki~n vs chay C\lC b9 bl,lng dAm la thoa man
t~i ti~t di~n tren m6 ..
R11 = 1.179, IkN:::; 1.656kN = 1x1.656 = <l>bRn D6.D5.2.ED18 (519)
4.1.1.1. Biln d{lng phing biin b{mg
' KiSm tra diSu ki~n vs bi~n d~ng phinh ban bl,lng, cac ban bl,lng chiu tac
. . ' '
dl,lng cua Ive nen t~p trung phai thoa man diSu ki~n: .. ··
D6.05.3.ED21 (520) 1::
Trong d6 Rn la sue khang danh dinh chiu tai tr9ng t~p trung .
. a) D6i vai lrl:l giua
D6i v6i cac tr\1 gifra, Rn duqc tinh nhu sau:
~" ~o.s1;[1+J(~J(:J]pt?1 f)6.D53.ED22 (521)
. Trong d6::d = I.132mm la chiSu caom(lt c~t thep; ·
[ ( 300 )(13)] 200.000x345x32 _ · R,, =0,8xl32 1+3 1.1 32 32 13 xlO 3 D6.D5.3.ED22 (522) Rn= 2.331,lkN (523)
<Pw: h~ s6 sue khang ch6ng phinh ban b\mg quy djnh trong D6.5.4.2,
<Pw = 0,8.
Thay vao cong thuc tren thi thfty r~ng m~t dt tren tr\l thoa man di€u
ki~n v€ ch6ng phinh ban b\,lng:
Rll = 1.558,0kN ~ l.864,9kN = 0,8x2.331,1 = <I>wRn Thoa man (524)