Vc Tnhtonvngsntheo5574 2012 141118043739 Conversion Gate01

7/26/2019 Vc Tnhtonvngsntheo5574 2012 141118043739 Conversion Gate01

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TNH TON VNG SN BTCTTHEO TCVN 5574-2012

KS. NGUYN NH NGHA

O TO KIN TRC & XY DNG VIETCONSVN PHNG : 137IN BIN PH, P.AKAO Q.1 TP.HCM

IN THOI : 0906 98 92 97 0932 111 790 0908 603 218


2/16

2

KHI NIM CHUNGKhng ch vng sn nhm:

Trch mt m quan;

Lm bong lp ptrt;

Lm h hng trntreo, lm nt cu kin phi ktcu(vch ngn, tng);

Trnh gy tm l s hi cho ngi s dng.


3/16

3


4/16

4

KHI NIM CHUNG

- vng c tnh ton vi ti tiu chun

(TTGH II). Tisao?-vng BTCT tnh ton bng phngphp c hc

kt cu, nhng phithay EJ=B

EJ :

cng

dn

hi

ca

vt

liu

l

tngB :

cng

ca

b

tng

ct

thp


5/16

5

KHI NIM CHUNG

B

-

cng ca b tng ct thp c xt n:

+ Bin dng do ca b tng,

+ S c mt ca ct thp,

+ S xut hin khe nt trong vng ko.


6/16

6


7/167

KHI NIM CHUNG

vng do bin dng un ca cu kin c tit din khng i gy rac tnh theo cng thc sau:

l cng ton phn ti tit din c momen ln nht.

l h s ph thuc lin kt v s ti trng, tra bngph lc F tiu chun TCVN 5574:2012.

2 2M 1

f l lEJ r

1 M

r B


8/16

8


9/16

9

Kim tra kh nng ntiu kin khng ch khng b nt nh sau:

Trong :+ M l momen do ngoi lc trn tit din ang xt;+ Mcrcl momen chng nt ca tit din.

crcM M

crc bt ,ser plM R W


10/16

10

Wpl momen khng un ca tit din i vi th chu kongoi cng c xt n bin dng khng n hi ca btng vng ko.

;

Ibo, Iso, Iso ln lt l momen quan tnh i vi trctrung ha ca din tch vng b tng chu nn, ca dintch thp chu ko v din tch thp chu nn;Sb0 momen tnh i vi trc trung ha ca din tch vngb tng chiu ko.

Kim tra kh nng nt

'

bo so so

pl bo2 I I IW S

h x

'

s

b

EE


11/16

11

cong ton phn,xc nhtheo cng thcsau:

1/r1 : cong do tc dng ngn hn caton b ti trng;

1/r2 : cong do tc dng ngn hn ca ti trngdi hn;1/r3 : cong do tc dngdi hn ca ti trngdi hn.

vng sn BTCT c khe nt

1 2 3

1 1 1 1r r r r


12/16

12

cng cab tng ctthp khi c nt ctnh nhsau:

+ h l chiucao tit din,+ a l khongcch tmp ngoi ntm thp;

+ b lb rng tit din

.+ Khi tnh ton vi ti trng tc dng ngn hn =0,45, tcdngdi hn vi mkhng kh trn 40% th =0,15, m


13/16

13

Tnh Z

Sn tit din ch nht, t ctthp nth:


'

2f

f

0

o

f

h

hz h 1

2

o

z h 12


14/16

14



15/16

15


'bo so sopl bo

2 I I IW S

h x


16/16

CM N CC BN THEO DI

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Vc Tnhtonvngsntheo5574 2012 141118043739 Conversion Gate01