thuyetminhdacodinh2

Khoa Cng Trnh Bin V Du Kh Ging Vin: TH.S Bi Th Anh n C nh 2 Sinh Vin : Nhm 2_Lp 56CB2

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Nhim v ca n :Thit k khi chn cng trnh bin trng lc trong giai on khai

thc.

I. GII THIU C IM CNG TRNH

Cng trnh bin trng lc l loi cng trnh lm vic theo nguyn l mng nng, ng n

nh trn mt y bin nh trng lng bn thn v trng lng cng ngh.

Mt trong nhng u im n bt ca cng trnh bin trng lc l ton b ( hoc phn ln)

kt cu cng trnh c ch to trn b, sau lai dt cng trnh ra v tr xy dng nh chm,

gim thiu thi gian thi cng ngoi khi do vy trnh c nhng ri do khi thi cng di ngy

ngoi khi.

tn dng c nhng u im trn, cc cng trnh phi c thit k sao ch t ni

n nh trong qu trnh lai dt t v tr thi cng ven b n ni xy dng cng trnh. tang n

nh cho cng trnh, thng cu to phn ln h thp trng tm cng trnh. Trng tm cng

thp th cng trnh cng n nh.

Ngoi ra, b tng cn l vt liu r tin hn thp, c th s dng ngun nhn cng a

phng. Kh nng chng n mn xm thc ca mi trng mnh nh nc bin tt. Qu trnh

duy tu bo dng t hn so vi cng trnh bin c nh bng thp.C th s dng cc khong

khng gian ngm trong cng trnh nh cc silo.

Cc nhc im m cng trnh bin trng lc l : - Kch thc trng lng ln dn n

tnh linh hot km. i hi thi cng trn b phi c kh, cng nc su.

II. C IM KH TNG HI VN, A CHT CNG TRNH.

1. S liu thy triu v nc dng ti v tr xy dng cng trnh.

Cc thng s bi 2

Bin ng triu ln nht d1 (m) 2

Nc dng tng ng vi bo thit k d2 ( m ) 1.5

2. su nc ti v tr xy dng cng trnh.

do=30m

3. S liu v sng.


2

Chu

k lp Hng N NE E SE S SW W NW

100

Nm

H, m 10.8 16.4 9.9 6.2 8.6 13.1 9.3 7.4

T, s 10.3 13.4 11.6 10.8 12.4 12.5 12 12.3

50

Nm

H, m 9.7 15.6 9.2 5.6 8 12.4 8.8 6.9

T, s 10 14.1 11.5 10.5 12.1 12.4 11.9 11.7

25

Nm

H, m 8.8 14.7 8.7 5.2 7.7 11.1 8.5 6.5

T, s 9.9 14.3 11.4 10.2 11.8 12.4 11.8 11.7

5 Nm H, m 5.6 13.7 6.8 3.8 6.2 9.7 7.1 4.8

T, s 9.4 13.9 11 9.4 10.6 12.1 11.6 11

1 Nm H, m 2.6 11.8 4.8 2.4 4.6 7.3 5.8 3

T, s 9.1 13.3 10.5 9.1 9.2 11.7 11.3 9.9

4. S liu v dng chy.

Vn tc dng chy thit k vi chu k lp 100 nm, tng ng vi cc hng sng.

Vn tc dng chy mt :

Cc thng s Hng sng

N NE E SE S SW W NW

Vn tc (cm/s) 93 137 100 173 224 181 178 121

Hng () 240 242 277 41 68 79 78 134

Vn tc dng chy y :

Cc thng s Hng sng

N NE E SE S SW W NW

Vn tc (cm/s) 68 119 90 109 182 137 119 97

Hng () 2 300 60 295 329 53 329 197

5. S liu v h bm.

Phm vi h bm t mc nc Chiu dy

h bm

thp nht tr xung (mm)

T mc nc thp nht 0 (m) n -4 (m) 80mm

T - 4 (m) n -8 (m) 87mm


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Phm vi h bm t mc nc Chiu dy

h bm

thp nht tr xung (mm)

T -8(m) n -10 (m) 100mm

T -10 (m) n y bin 70mm

Trng lng ring h bm : =1.6 T/m3

6. S liu v gi.

Vn tc gi trung bnh o trong 3 giy vi chu k lp 100 nm o d cao 10m so vi mc

nc chun.

Chu k

lp - nm N NE E SE S SW W NW

Vn tc gi trung bnh o trong 2 pht

100 38.4 49.3 0 20.8 2 35.7 34.2 33.5

50 36.2 45 9.1 19.2 1.4 33.4 32.7 31.8

25 34.2 40.6 7.4 18.2 0.4 31.5 30.4 29.2

10 30.6 37.5 6.3 16.8 9.2 28.2 27.5 26.5

5 28.5 34.6 5.2 15.5 8.4 26.2 25.2 21.3

1 23 26 2 12.7 6 21 20 18

Chu k


Vn tc gi trung bnh o trong 1 pht

100 39.7 50.9 1 21.4 2.7 36.9 35.3 34.6

50 37.4 46.5 0.1 19.8 22.1 34.5 33.8 32.8

25 35.3 41.9 28.3 18.8 21.1 32.5 31.4 30.2

10 31.6 38.7 27.2 17.4 19.8 29.1 28.4 27.4

5 29.4 35.7 26 16 19 27.1 26 22

1 23.8 26.9 22.7 13.1 16.5 21.7 20.7 18.6

Chu k


Vn tc gi trung bnh o trong 3 giy

100 44.7 57.4 4.9 24.2 5.6 41.6 39.8 39

50 42.1 52.4 33.9 22.3 24.9 38.9 38.1 37


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Chu k


Vn tc gi trung bnh o trong 3 giy

25 39.8 47.3 31.9 21.2 23.7 36.7 35.4 34

10 35.6 43.7 30.6 19.6 22.4 32.8 32 30.8

5 33.2 40.3 29.3 18 21.4 30.5 29.3 24.8

1 26.8 30.3 25.6 14.8 18.6 24.4 23.3 21

7. S liu v a cht cng trnh.

STT Cao trnh Dy(m) Loi t

n

(kN/m3)

'

()

c'

(kPa)

E0

(Mpa) T n

1 0.00 -h1 h1 Ct ht trung 20 35 0 46.7

2 -h1 -(h1+h2) h2 Ct pha 20 27.5 0 10

3 - - h3 Ct nh 20 32.5 0 20

4 - - h4 t st 18.5 20 8 3.3

5 - - h5 St pha 19.5 22 2 4.7

6 - - h6 Ct nh ln

bn

19 32.5 0 26.7

7 - - h7 St pha 18 22 5 6.7

8 - - h8 Ct nh 19 35 0 26.7

9 - - h9 St cng 19 18 10 6.7

10 - - h10 Ct pha nh 20 32.5 0 20

S 2

h1, h3, h5, h7, h9 (m) 3

h2, h4, h6, h8 (m) 4

III. C IM CNG TRNH.

1. su nc v nc dng.

su nc ti v tr xy dng cng trnh: do = 30m

- Nc dng do triu ln nht : d1 = 2m

- Nc dng tng ng vi bo thit k : d2 = 1.5m

Mc nc tnh ton : d =do + d1 + d2 = 30 + 2 + 1.5 = 33.5 (m).

2. Hng t cng trnh.

Cng trnh dng tr ng vi hnh dng tr v mng l dng trn. Do vy vic la chn

hng t cnh trnh ch yu ph thuc vo hnh dng ca kt cu thng tng gim thiu


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tc ng ca mi trng. Tuy nhin ti trng mi trng tc dng ln thng tng ch l ti trng

gi m ch chim khong 10 -15% tng ti trng tc dng ln cng trnh. Chnh v nhng l do

ny m vic la chn hng t cng trnh bin b tng trng lc nh th no cng khng qu

quan trng min sao cho vic thi cng thng tng cng d dng cng tt.

3. M t kin trc cng trnh.

Kin trc cng trnh gm 5 phn chnh: thng tng, kt cu thng tng, tr , mng,

chn khay.

Thng tng bao gm :

- Khi nh : gm nh cho 12 ngi, cha thit b o kh tng hi vn. Dng nh hnh tam

gic trn mi c vn kh tng c t cc dng c o.

- Sn chu lc : kt cu nh v trong longf lm b nc n 50m3.

- Sn cng tc nh v sinh kho cha gi v xung, b cha du, cu thang di ng.

Tr bao gm :

- Tr lm bng b tng ct thp hoc BTCT UST tit dn vnh khuyn.

- Dm thng tng.

mng bao gm :

- mng l khi BTCT hoc BTCT UST rng vi mt bng trn hay vung.

- H thng chn khay chy vng quanh mng.

- Pha trong mng c cc h dm sn b tng ct thp, hoc vch cng bn y, bn np, bn

thnh chia thnh cc khoang rng.

( Vi n n coi nh ko c thit b cp tu.)

4. Trng lng phn thng tng v cc thit b.

- Khi nh = 70T, hot ti = 2T, d tr lng thc thc phm = 8T, nc ngt = 50T.

- H thng dm thp chu lc sn chu lc = 38T.


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- Sn cng tc : nh VS = 0,75T, kho = 1,45T, b cha du = 2,5T, trng lng bn than sn cng

tc = 11T.

5. c trng c hc ca vt liu.

* Thp cng cao c c trng c l :

- Kh lng ring t = 7850 kG/m3

- Cng tiu chun Rc = 17.000 kG/cm2

- Cng tnh tan R = 11.000 kG/cm2

- Modul n hi E = 2.000.000 kG/cm2

* Thp thng nhm CI, CII, CIII...

* B tng :

- Vi cu kin b tng ct thp thng : BT mc # 400

- Vi cu kin BTCT UST: BT mc # 500

IV. PHNG N THI CNG D KIN.

1. Bc 1: ch to trn b trong kh.

Ton b phn mng BTCT v mt phn ca tr BTCT c ch to trong kh. Sau khi ch

to xong, tho nc vo phn KC ch to ny t ni c v ko ra khu nc gn b

thi cng tip bc hai.

2. Bc 2: Ghp phao ph vo cng trnh (gn b).

Ti v tr gn b, tin hnh gn cc phao ph bng thp vo Khi chn ch to t bc 1

tng tnh ni v n nh ca h Khi chn - phao ph.

3. Bc 3: Ch to v lp dng hon chnh ( gn b).

Tip tc ch to nt phn tr BTCT cn li, ng thi lp khi thng tng vo khi chn

. H khi chn v phao ph phi m bo tnh ni v tnh n nh cho ton b h

thng cng trnh sau khi ch to v lp dng bc 3 ny.

4. Bc 4: Lai dt ra v tr xy dng ngoi khi.

Dng cc tu ko, lai dt h khi chn - phao ph - thng tng ra ngoi khi ( ni v

tr s c nh cng trnh).

5. Bc 5: San dn nn v bm nc nh chm cng trnh.

Ti v tr c nh cng trnh, tin hnh cng tc san dn nn t, sau bm nc vo

khi chn cng trnh t t h xung.ch phao ph lc ny vn ni trn mt nc

v c tc dng nh v cng trnh, dn hng cho cng trnh t t h xung y bin.


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6. Bc 6: Hon chnh cc hng mc khc.

Sau khi cng trnh h xung, tin hnh cc cng tc khc nhau nh : bm pht va b

tng vo khe gia y mng v nn t, dn vt liu vo khi chn (nu cn), tho d

phao ph ra khi cng trnh, hon tt cc vic ph khc.

V. GII PHP KT CU.

1. Gii php kt cu dm thng tng.

- Kt cu thng tng c dng sn phng c cu to bng thp hnh, thp ng hoc BTCT.

- V cng trnh lm bng BTCT nn chn lun cu to ca kt cu thng tng lm

bng BTCT ton khi. Vi tr c cc dng sau (Hnh v):

1. Dm thng

tng

2. Thnh tr

3. Giao gia cc dm

2. Gii php kt cu tr .

Vi kt cu thng tng nh u bi cho th ch c mt tr .

- Tr c tit din hnh vnh khuyn. i vi tc dng ca mi trng bin th y l

tit din c li nht v kh nng chu lc, tc dng ca ti trng ln mi pha ca kt cu l nh

nhau. Mt khc ta c li dng khong rng bn trong ca tr t cc thit b khoan, ng

khoan, lm cu thang ln xung v phc v cc hot ng cng ngh khc.

- Trong tr c cc bn vch cch nhau mt khong h(m), to cng v n nh cho

vch.

- Kch thc mt ct ngang v chiu dy ca tr c th thay i.

2

13

3

1

2


8

- Vic thay i tit din ko theo s phc tp trong thi cng. M su nc ti v tr t

cng trnh l 21 m, khng qu ln. Do vy ta chn tit din tr khng i trn sut chiu di.

3. Gii php kt cu mng.

Vic chn kch thc mng ph thuc phn ln vo phng php thi cng v cc iu kin v

n nh v kh nng t ni, iu kin bn v bin dng ca mng. mng hnh trn, c th l

hnh vung, ch nht, hnh vm hoc c th l tp hp ca cc xi l.

Ni dung th 1 : Xy dng phng n.

1. Xy dng phng n kin trc.

1.1.Xc nh chiu cao KC.

Chiu cao KC c xc nh theo cng thc:

Hc= do+d1+d2+..Hmax+o

Trong :

Hc: Chiu cao KC (tnh t mt y bin n mp di ca kt cu thng tng)

do: su nc ti v tr xy dng

d1: bin triu

d2: bin nc dng do bo

: h s iu chnh chiu cao sng

: h s (0.5-0.7) ph thuc l thuyt sng tnh ton

o: tnh khng (o 1.5 m)

- Xc nh L thuyt sng vi : dtt = MNTT = 33.5 (m) ;

H = 16.4 (m) ; T= 14.3s.

*Xc nh chu k biu kin Tapp : d/gT2

= 0.016 > 0.01 nn tra bng theo API

(t-13), vi V1/gT = 1.37/(9.81x14.3) =0.0097.

Trong : V1 : vn tc mt ln nht ng vi hng sng ch o NE.

Tra bng ta c : Tapp/T = 1.08 => Tapp = 15.444 (s).

Tra bng vi : 3

2 2

16.47 10

9.81 15.444app

Hx

gT x


9

2 2

33.50.014

9.81 15.444app

d

gT x

Thuc L thuyt sng Stokes bc 5.

Khi : = 0.7

Vi cc d liu cho thay vo cng thc ta c:

Hc= 30+2+1.5+0.7x16.4+1.5 = 46.48 (m)

Chn chiu cao KC tnh ton l Hc = 47 (m).

1.2.La chn s b cc kch thc KC.

*S b la chn cc kch thc ca cc b phn trong mng da vo ti liu BTCT :

+ Kch thc dm ph : hdmph = )20

1

12

1( .lnhp

+ Kch thc dm chnh :hdm chnh = )12

1

8

1( .lnhp

+ B rng dm chn trong khong b= (0.30.5).hdm

+Chiu dy bn :

1

35

250

b d m

b

h l

h

a) Tr v kt cu thng tng.

+ Tr :

- Tit din tr l hnh vnh khuyn, ng knh tr s b chn l 6m.

- Chiu dy thnh tr s b chn l 0.5m v khng thay i trn sut chiu di, do

su nc khng ln (d = 30 m), nn p lc thy tnh cng khng ln.

- Bn trong tr c cc bn vch cng, s b chn chiu dy bn vch l 0.4m >

0.25m, do cc vch ny bn trong tr , khng tip xc vi mi trng xm thc nn lp bo

v nh hn lp bo v thnh tr . Khong cch gia cc bn vch i vi tng phng n

c chn s b v c th hin trn hnh v (trong phn sau), v nm trong khong t 57m.

+ Kt cu thng tng:

- Kt cu thng tng gm 4 dm giao nhau. S b chn chiu di ca dm l

16m, do chiu rng thng tng rng 16m. V ng knh ca tr l 7m nn phn tha ca

dm c coi l cng xn c chiu di l 4.5m, t s b chn kch thc dm l 0.5x1m, do


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chiu cao dm bng 1/3 chiu di on cng xn, chiu cao dm s c gim dn, n mp

ngoi ta chn chiu cao dm l 0.6m > 0.15m, sao cho dc t 1/6 1/3. Mc ch gim l do

mmen gim.

- Cc kch thc ca dm thng tng th hin trn hnh v sau:

1. Dm thng tng

2. Thnh tr

3. Giao gia cc dm

b) Kt cu mng.

Kch thc mng tha mn cc iu kin:

- iu kin v thi cng ( l kh nng t ni ca cng trnh trong giai on u

khi thi cng xong t tr u tin)

T < H

- iu kin v n nh.

ho> 0

Trong :

T: l mn nc ca cng trnh.

H: Chiu cao ca .

ho: chiu cao n nh ban u ca cng trnh.

7000

2000800

800

800

1

2

3

3

3500

1


11

Trong cc loi hnh dng ca mng th kt cu mng dng hnh trn l ti u.

Bi v: kt cu hnh trn chu lc t mi pha l nh nhau. mng chu p lc thy tnh t mi

pha, trnh cho cc bn thnh b chu un ta s dng kt cu hnh trn.

S b la chn cu to mng nh sau:

- ng knh mng: 28m


12

80

0 7000

14000

60

00

60

00

60

00

11

00

0

600

40

0

800

15

00

800

50

05

00

1

2

3 4

5 6 7

8

9

11

121314

1015

16

11

9

10

8

7

6

5

4

3

2

1

GHI CH

12

13

15

14

16

17

800

5001000

10

00

18

17

18

48

00

0

7000

800x800

1 1

22

80

0

10

00

60

00

15

00

60

00

60

00

1000

800

600

28000175007000


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Chn s b kch thc mng

Cu kin D, l (m)

h

(m)

b

(m) S lng

V

(m3)

Trng lng

(T)

y

Bn y 28 0.5 1 307.72 769.3

Dm Bo 27 1 1 1 81.64 204.1

Dm vng bn y 17.5 0.8 0.8 1 33.56032 83.9008

Dm ph hng tm 5.25 1 0.6 8 25.2 63

Thnh Bn thnh 28 10 0.5 1 431.75 1079.375

Dm vng bn thnh 27 1 1 1 81.64 204.1

Np

Bn np 28 0.5 1 307.72 769.3

Dm vng bn np 17.5 0.8 0.8 1 33.56032 83.9008

Dm Bo 27 1 1 1 81.64 204.1

Dm ph hng tm 5.25 1 0.6 8 25.2 63

Dm

chnh

Nhnh np 11 1.5 0.8 8 105.6 264

Nhnh y 11 1.5 0.8 8 105.6 264

Chn

khay

Vng ngoi 28 0.5 0.5 1 21.5875 53.96875

Tr trong 7 0.5 0.8 1 7.7872 19.468

Ct

chng

Ct chng trong 9 0.8 0.6 16 69.12 172.8

Ct chng bin 9 1 0.8 8 57.6 144

Tng 4442.31335 b) Phng n 2: Tr c tit din khng i, mng c dng np mi trn xoay.

Bng tnh cc thng s ca phng n 2:

STT Tn cu kin Cao trnh D,l (m) b,t ( m) h (m)

1 Tr di 0 11 7 0.8 11

2 Tr trn 11 47 7 0.5 36

3 Vch 1 10.511 6 0.5

4 Vch 2 16.817.2 6 0.4

5 Vch 3 22.8 23.2 6 0.4

6 Vch 4 28.8 29.2 6 0.4

7 Vch 5 34.8 35.2 6 0.4

8 Vch 6 40.8 41.2 6 0.4

9 Kt cu thng tng 4647 14 0.8 1


14

80

0

7000

16000

60

00

60

00

60

00

500

40

0

800

1

2

3 4

5

8

9

11

121314

15

16

500

48

00

0

28000

600

500

500

175007000

7000

800x800

1 1

22

60

00

11

00

06

00

06

00

0


15

Chn s b kch thc mng

Cu kin D, l (m) h (m) b S lng

y Bn y 27 0.5 1

Dm vng bn y 17.5 1 0.5 1

Thnh

Bn thnh 28 7 0.5 1

Dm vng nh

bn thnh 28 1.2 0.5 1

Np Bn np trn xoay 22.7 3.5 0.4 1

Dm

np 11.5 1.2 0.5 8

y 11 1.5 0.6 8

Chn

khay

Vng ngoi 28 0.5 0.5 1

Tr trong 7 0.5 0.8 1

Cng thc tnh th tch hnh cu :

V= 4r3/3 vi r l bn knh.

Khi tnh khi lng bn np trn xoay, ta coi bn np l mt hnh cu ri tnh th tch ca hnh

cu, n l hiu s ca 2 hnh cu (bn trong v bn ngoi, c hiu s ng knh bng b dy ca

bn np

2. Kim tra cc kch thc kt cu mng ca phng n chn.

*Kim tra n nh ni:

- Vi cc kch thc s b nh chn trn, trng lng ca tng cu kin c thng

k trong bng sau:

Vi ta Zi c ly so vi gc ta c chn l tm ca tr, nm trn mt y bin.

http://vi.wikipedia.org/wiki/B%C3%A1n_k%C3%ADnh


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Cu kin Gi(T) ZiG(m) MiZG,Tm

y

Bn y 769.3 0.3 230.79

Dm Bo 204.1 0.55 112.255

Dm vng bn y 83.9008 0.7 58.73056

Dm ph hng tm 63 0.6 37.8

Thnh Bn thnh 1079.38 5.5 5936.563

Dm vng bn thnh 204.1 5.5 1122.55

Np

Bn np 769.3 10.8 8308.44

Dm vng bn np 83.9008 10.6 889.3485

Dm Bo 204.1 10.35 2112.435

Dm ph hng tm 63 10.7 674.1

Dm tr Nhnh np 264 10.4 2745.6

Nhnh y 264 0.5 132

Chn khay Vng ngoi 53.9688 -0.25 -13.4922

Tr trong 19.468 -0.25 -4.867

Ct chng Ct chng trong 172.8 5.5 950.4

Ct chng bin 144 5.5 792

Tng 4442.31 24084.65

Khi vt th trong mi trng nc n chu mt lc y ni, vt cn bng vi lc y ni khi

trng lng ca n bng lc y ni.

FN = GKC = 4442.31 T.

Th tch nc m khi chn chon ch, vi trng lng ring nc bin nb=1.025T/m3 :

V= KCD

nb

G

4333.96 (m

3).

Do mng chn c phn chn khay cao 0.5(m), cho nn phn th tch mng v tr

khng tnh phn chn khay v c cc phn cu kin tnh t mp y bn y tr xung l:

Vv= V - V1- V2- V3

Xc nh th tch chon nc phn pha di bn y:

+/ Vng ngoi chn khay:


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Pck=53.97 T => V1 = 52.65 (m3)

+/ Tr trong chn khay :

Ptt = 19.47 T => V2 = 19 (m3)

+/ Dm chnh di bn y:

Pdc = 264 T => V3 =257.7 (m3)

Vy c : Vv = 4004.61 (m3)

T y xc nh c mn nc ca phn kt cu khi tho nc vo kh cch y chn

khay mt on:

T = 0.5+ 2

4004.610.5 7( )

28

4

v

de

Vm

S

Vy T = 7 (m) < 11 m => tha mn iu kin ni.

*iu kin n nh tnh:

Chiu cao n nh ban u c xc nh theo cng thc sau:

ho = r - ZG + ZC

Trong :

ZG : Ta trng tm ca vt ni.

ZC : Ta ph tm ca phn ngp nc.

Cn r c xc nh: I

rV

Trong :

I : Mmen qun tnh mt ng nc.

V : Th tch vt chim ch.

Lng nc chon ch nh tnh trn l:

V = 4004.61 (m3).

Mmen qun tnh ng mt nc :


18

I = 4

64D

= 4 428 30171.86( )

64m

T , ta c : 30171.86

4004.61

Ir

V 7.53(m)

+/ Xc nh tm ni :

Ta tm ni c tnh theo cng thc sau:

ZC = xyM

V

Trong mmen tnh th tch i vi trc ta OXY l :

2 2( )

2

ck ck de ckxy

S h S T hM

Din tch chn khay : Sck = 2 2 2 2 2( 2 ) [28 (28 2*0.5) ] 43.2( )

4 4D D t m

Din tch phn : S = 228

4

615.75(m

2)

Chiu cao chn khay : hck = 0.5m

Vy : M xy = 13013.12 (m4) => ZC = 3.5 (m)

ZG = .i i

i

G Z

G

24084.656.01( )

4004.61m

T y tnh c : ho = 7.53 6.01 + 3.5 = 5.02 (m) > 0 => tha mn iu kin n nh tnh.

Kt lun : Cc kch thc kt cu cng trnh chn l tng i hp l.

NI DUNG TH 2 : TNH TON TI TRNG

I. TNH TON CC TI TRNG

I.1. Ti trng bn thn khi chn

- Ta c bng tnh ton ti trng bn thn khi chn :


19

Cu kin

D, l

(m)

h

(m)

b

(m)

S

lng

V

(m3)

Trng lng

(T)

y

Bn y 28 0.5 1 307.72 769.3

Dm Bo 27 1 1 1 81.64 204.1

Dm vng bn y 17.5 0.8 0.8 1 33.56032 83.9008

Dm ph hng tm 5.25 1 0.6 8 25.2 63

Thnh Bn thnh 28 10 0.5 1 431.75 1079.375

Dm vng bn thnh 27 1 1 1 81.64 204.1

Np

Bn np 28 0.5 1 307.72 769.3

Dm vng bn np 17.5 0.8 0.8 1 33.56032 83.9008

Dm Bo 27 1 1 1 81.64 204.1

Dm ph hng tm 5.25 1 0.6 8 25.2 63

Dm

chnh

Nhnh np 11 1.5 0.8 8 105.6 264

Nhnh y 11 1.5 0.8 8 105.6 264

Chn

khay

Vng ngoi 28 0.5 0.5 1 21.5875 53.96875

Tr trong 7 0.5 0.8 1 7.7872 19.468

Ct

chng

Ct chng trong 9 0.8 0.6 16 69.12 172.8

Ct chng bin 9 1 0.8 8 57.6 144

Tng 4442.31335

STT Tn cu kin Cao trnh

D,l

(m)

b,t

(m)

h

(m)

V

(m3)

Trng lng

(T)

1 Tr di 0 11 7 0.8 11 171.3184 428.296

2 Tr trn 11 48 7 0.6 37 446.1312 1115.328

3 Vch 1 10.811.2 5.4 0.4 9.15624 22.8906

4 Vch 2 16.8 17.2 5.8 0.4 10.56296 26.4074

5 Vch 3 22.823.2 5.8 0.4 10.56296 26.4074

6 Vch 4 28.8 29.2 5.8 0.4 10.56296 26.4074

7 Vch 5 34.8 35.2 5.8 0.4 10.56296 26.4074

8 Vch 6 40.8 41.2 5.8 0.4 10.56296 26.4074

9 KC thng tng 46 47 14 0.6 1 31.92 79.8

TNG 711.3406 1778.3516


20

Tng ti trng bn thn khi chn l: 6220.67 (T)

I.2. Ti trng h bm

- Xc nh ti trng h bm ln kt cu tnh t mc nc thp nht xung y bin

Khi lng h bm ti thanh th i l:

mh (i) = h.Ahi.Li

Trong :

h: khi lng ring ca h bm trong nc (h = 1300-1025 = 275 kg/m3)

Ah: Din tch ca h bm c tnh theo cng thc:

Ahi = /4*[(Di + 2t)2 - Di

2]

Di: ng knh tit din ngoi tr hoc khi

t: chiu dy ca h bm

Li: chiu di ca cu kin

Ta c tng ti trng h bm:40.44 (T)

I.3. Ti trng thng tng

- Ti trng thng tng l ti trng thng ng, bao gm: khi nh , hot ti ngi s dng, d

tr lng thc thc phm, nc ngt, sn chu lc, nh v sinh, kho cha, sn cng tc

Ta c tng ti trng thng tng: 183.7 (T)

I.4. Ti trng gi

- Ti trng gi c tnh ton theo tiu chun API vi hng tng ng vi hng sng

chn:

Hng: ng Bc(NE)

- Tnh ti trng do gi tc dng ln phn cng trnh nm pha trn mc nc tnh. Bn cht ca

ti trng gi l ng, nhng thnh phn ng ca gi ch nh hng n thng tng xt vi

KC nn trong n ny ta coi trong tnh ton ti trng gi l tnh.

- Cng thc xc nh ti trng gi theo API:

F = 0,0473.Vz2.Cs.A


21

Trong :

F: l lc gi tc dng ln kt cu (N).

Vz: Vn tc gi trung bnh o trong 1h ti cao z so vi mc nc tnh ton (km/h).

A: Hnh chiu din tch ca vt cn ln phng vung gc hng gi (m2).

Cs : H s kh ng (xc nh theo qui phm).

Loi kt cu Cs

Kt cu dm, nh tng c 1.5

Kt cu tr trn 0.5

Sn cng tc 1

Vz = .V10.(z/10)

Trong :

V10: Vn tc gi trung bnh o trong 3s ti cao 10m so vi mc nc tnh ton (km/h), V10 =

57.4 m/s = 206.64 km/h

: H s gi git, = 1.33

: h s ly tha, = 0.125

z: cao im cn tnh

S tnh ti trng sng tc dng ln tr


22

- Bng tnh ton ti trng gi ln phn tr :

z(so vi dtt) Vz(km/h) A F(N) F(T)

0 0 0 0.000

1 218.30618 7 7889.714 0.789

2 233.97477 7 9062.901 0.906

3 243.65659 7 9828.461 0.983

4 250.76795 7 10410.54 1.041

5 256.42658 7 10885.67 1.089

6 261.14467 7 11289.94 1.129

7 265.20142 7 11643.43 1.164

8 268.76644 7 11958.57 1.196

9 271.95077 7 12243.62 1.224

10 274.8312 7 12504.35 1.250

11 277.46314 7 12745 1.274

12 279.88792 7 12968.73 1.297

13.5 283.20402 7 13277.86 1.328

Sum 14.67087817

140003000 8000 3000

MNTT

F3

F2

F1

8000

13500

2000


23

- Bng tnh ton ti trng gi ln phn thng tng:

Loi b(m) h(m) A(m2) Cs Vz(km/h) F(N) F(T)

Khi nh 14 8 112 1.5 295.997 696219.8 69.622

Sn kh tng 14 2 28 1 302.387 121100.5 12.110

Sum 81.73203

Ta c tng ti trng gi l: 96.403 (T)

I.5. Ti trng sng v dng chy

I.5.1. Xc nh l thuyt sng tnh ton

- Vic p dng l thuyt sng cho chuyn ng sng s c cn c vo tng quan t l gia

H/gT2

app v d/gT2

app

- Xc nh chu k biu kin Tapp :

2 2

33.5

. 9.81*14.3

d

g T = 0.0166 > 0.01

1.37

9.81*14.3

mV

gT = = 9.76*10

-3

Tra th 2.3.1-2 API RP c Tapp/T = 1.08 => Tapp = 15.444 s


24

th 2.3.1-3 API RP 2A-WSD

- Ta c: 2 2

16.4

9.81*15.15app

H

gT = 0.007138

2 2

33.5

9.81*15.444app

d

gT = 0.0143

Vy chn l thuyt sng Stoke bc 5 tnh ton vi hng sng NE chu k lp 100 nm.


25

I.5.2. Tnh ton vn tc v gia tc phn t nc theo l thuyt sng Stokes bc 5

- Chn h trc ta :

+ Trc Ox nm ngang, trng vi phng chuyn ng sng

+ Trc Oy nm ngang, vung gc Ox

+ Trc Oz thng ng, trng vi trc ca kt cu

- Vi sng c chiu cao H, s sng k v tn s vng lan truyn theo chiu dng ca trc x, th

dng ca b mt cht lng so vi mt nc tnh c th biu din di dng sau:

Trong : Fn - cc thng s hnh dng

; ; ;

a - thng s chiu cao sng.

- cc thng s hnh dng ca profil sng, ph thuc vo tr s kd = 2d/L

(tc l d/L), c tra bng 2.1 theo phng php ni suy.

Cc thng s a v F22, F33, ,F55 c quan h vi chiu cao sng H:

- Vn tc phn t nc:

Vn tc ca phn t nc c to (x,z) do s lan truyn sng b mt trong vng c su d

c xc nh theo biu thc sau:

)(sin)(

)]([

)(cos)(

)]([

5

1

5

1

tkxnnkdsh

dznkshG

kvV

tkxnnkdsh

dznkchG

kuV

n

nz

n

nx

Trong : Gn( ) - l cc gi tr ph thuc vo thng s a.

G1 = aG11 + a3G13 + a

5G15

G2= 2(a2G22 + a

4G24)

5

1nn )]tkx(ncos[.F

k

1)t,x(

aF1 244

222

2 F.aF.aF 355

333

3 F.aF.aF 444

4 F.aF 555

5 F.aF

55332422 F,...,F,F,F

)]FF(aF.aa[2H.k 55355

333

51n


26

G3= 3(a3G33 + a

5G35)

G4 = 4a4G44

G5 = 5a5G55

G11, G13, G15, G22, G24, G33, G35, G44, G55 l cc gi tr ph thuc vo t s d/L.

- Gia tc phn t nc:

Trong : Rn, Sn ( ) - l cc biu thc ph thuc vo cc thng s vn tc sng Gn (

).

R1 = 2U1 U1U2 U2U3 V1V2 V2V3

R2 = 4U2 U12 + V1

2 2U1U3 V1V3

R3 = 6U3 3U1U2 + 3V1V2 3U1U4 3V1V4

R4 = 8U4 2U22 + 2V2

2 4U1U3 + 4V1V3

R5 = 10U5 5U1U4 5U2U3 + 5V1V4 + V2V3

S1 = 2V1 3U1V2 3U2V1 5U2V3 5U3V2

S2 = 4V2 4U1.V3 4U3V1

S3 = 6V3 U1V2 + U2V1 5U1V4 5U4V1

S4 = 8V4 2U1V3 + 2U3V1 + 4U2V2

S5 = 10V5 3U1V4 + 3U4V1 U2V3 + 5U3V2

- Cc thng s khc ca sng:

+ Vn tc lan truyn sng:

+ Tn s vng:

5

1nn

2

z

5

1nn

2

x

)tkx(ncosS2

c.kW

)tkx(nsinR2

c.kW

51n

51n

2/12

41

2)]kd(th)CaCa1(

k

g[c


27

Trong : C1,C2 : l cc thng s tn s sng, c xc nh theo bng.

- Ta c cc c trng ca chuyn ng sng theo hng NE:

+ su nc tnh ton dtt = 33.5 m

+ Chiu cao sng H = 16.4 m

+ Chu k sng T= 14.3 s

+ Chiu di sng : L = 263.75 (m)

+ = 0.4394

+ k = 0.024

- Ta chia chu k T thnh 20 thi im, tin hnh tnh ton vn tc v gia tc sng ti 20 thi

im theo su nc. Kt qu tnh ton trn bng tnh excel c in trong ph lc.

I.5.3. Xc nh vn tc dng chy theo hng sng tnh ton

- Coi trc x trng vi hng truyn sng, gc gia phng dng chy y v dng chy mt hp

vi trc x gc 1 v 2(chiu dng ngc chiu kim ng h)

- Hng dng chy mt v dng chy y hp vi hng N gc 2420 v 300

0 do

1 = 2420 135

0 = 107

0

2 = 3000 135

0 = 165

0

- Ta coi dng chy bin i tuyn tnh theo su. Vn tc dng chy theo phng truyn sng

s c xc nh theo cng thc

z

d

VVVV dcdcdczdc

212)(

Trong :

d: l su nc tinh ton ti chn cng trnh

Vdc(z): vn tc dng chy ti im c su z so vi y bin (m/s)

Vdc1: vn tc dng chy mt theo phng truyn sng (m/s)

Vdc1 = 1.37(m/s)

Vdc2: vn tc dng chy y theo phng truyn sng (m/s)

)kd(th)CaCa1(gk 24

122


28

Vdc2 = 1.19 (m/s)

- Chiu vn tc dng chy ln 2 phng vung gc ta c kt qu:

Dng chy mt chiu theo phng x Vdcmx(m/s) 1.31

Dng chy mt chiu theo phng y Vdcmy (m/s) -0.4

Dng chy y chiu theo phng x Vdcdx (m/s) 0.307

Dng chy y chiu theo phng y Vdcdy (m/s) 1.149

- Ta c kt qu tnh ton vn tc dng chy theo su bng bng tnh excel c in trong ph

lc.

I.5.4. Xc nh ti trng sng v dng chy tc dng ln cng trnh

- Tng hp vn tc sng v dng chy theo cng thc:

Vx = Vsx + Vdc x

Vy = Vdc y

(Bng tng hp vn tc sng v dng chy c in trong ph lc)

- Xt t s :D/L = 0,026 < 0,2 => kch thc tr l b, ta c th tnh ton ti trng sng theo cng

thc Morisson.

- Cng thc tnh ti trng sng i vi vt th kch thc b (cng thc Morisson)


29

(N/m)

Trong cng thc Morisson thnh phn vn tc theo phng ngang bao gm 2 thnh phn l vn

tc sng v vn tc dng chy. Khi chn h trc to nh trn, i vi cng trnh dng tr trn

thng ng, n gin ta c th quy ti trng v cc nt trn trc Z ca cng trnh.

Thi im tnh ton l thi im ti trng sng v dng chy tc dng ln cng trnh l cc

i. V nguyn tc phi tin hnh chia chu k T thnh 20 thi im v chia cng trnh thnh cc

khong 1 m. Tnh ti trng sng v dng chy ti tng thi im, so snh ta tm c thi im

nguy him nht ng vi ti trng tnh ton l ln nht.

S tnh ti trng sng tc dng ln tr :

nxinxndx aACvvDCq .......5,0

nyinyndy aACvvDCq .......5,0

nzinzndz aACvvDCq .......5,0


30

- Ta c bng tnh ton ti trng sng v dng chy ti 20 thi im (bng tnh excel c th c

in trong ph lc)

t (s) Qx (T) Qy (T) Qz (T)

1T/20 -529.081 -7.72272 -24.3246

2T/20 -1370.87 -7.72272 -40.1989

3T/20 -1828.95 -7.72272 -34.6932

4T/20 -1904.92 -7.72272 -23.4915

5T/20 -1705.34 -7.11297 -13.4803

6T/20 -1375.77 -6.54419 -6.72794

7T/20 -1010.17 -6.27684 -2.93222

8T/20 -684.892 -6.27684 -0.97325

9T/20 -327.454 -6.02054 -0.16262

10T/20 -57.6479 -6.02054 -2.1E-32

11T/20 218.5995 -6.02054 0.162624

12T/20 559.147 -6.27684 0.973246

aa

aa

aa

aa

aa

aa

Hi

H


31

t (s) Qx (T) Qy (T) Qz (T)

13T/20 954.967 -6.27684 2.932224

14T/20 1357.266 -6.54419 6.727938

15T/20 1705.512 -7.11297 13.4803

16T/20 1939.157 -7.72272 23.49149

17T/20 1978.682 -7.72272 34.69321

18T/20 1906.189 -7.72272 40.19892

19T/20 1284.096 -7.72272 24.10682

20T/20 488.0823 -7.72272 2.15E-29

I.6.Ti trng y ni

- Khi cng trnh c h thy xung bin, ngoi cc loi ti trng k trn, cng trnh cn chu

tc ng ca ti trng y ni. Ti trng y ni ny c xu hng tc dng vo bn y ca

KC v y cng trnh ln.

- Ta tnh ti trng y ni theo mc nc tnh ton: dtt = 33.5 (m)

- Ti trng y ni c xc nh theo cng thc:

Pn = n.Vi

Trong :

n: Trng lng ring ca nc bin = 1.025 (T/m3).

Vi: Th tch chon nc ca phn t th i (m3)

Ta c tng ti trng y ni l: 7830.155 (T)

I.7. Khi lng nc km

- Khi lng nc km ch xut hin ti phn kt cu ngp nc tr xung y bin. y ta

tnh khi lng nc km theo mc nc tnh ton dtt = 33,5m. Khi lng nc km trn thanh

th i c xc nh theo cng thc:

mnk(i) = n.Cam.Vi

Trong :

n : Trng lng ring ca nc bin,n = 1.025 Tn/m3.

Cam: H s nc km.Ly Cam = 0.2

Vi: Th tch phn ngp nc ca thanh th i (m3), k n chiu dy h bm.


32

Ta c tng khi lng nc km l:1588.158 (t)

I.8. Tnh ton ti trng vt liu dn

- Do yu cu n nh ca khi chn t ra ngay t khi cng trnh va mi h thy xong nn

khi tnh ton, tng tnh an ton ta khng k n phn trng lng h bm.

Cc ti trng thng tng, bn thn v thit b c hng xung v c chiu hng tng n nh

cho cng trnh.

Ti trng y ni hng ln v lm gim n nh cng trnh.

- Ta c cc ti trng tc dng vo khi chn theo phng ng:

+ Ti trng thng tng v thit b: 183.7 (T)

+ Ti trng bn thn khi chn : 6220.67 (T)

+ Ti trng y ni ln nht : 7830.155 (T)

Chiu ln trc z c: 7830.155 6220.67 183.7 = 1425.785 (T)

- Nh vy, di tc dng ti trng bn thn ca cng trnh (gm ti trng thng tng v ti

trng bn thn khi chn ) th cng trnh khng th t n nh v ti trng y ni qu ln.

- Khi y mng ca cng trnh tip xc v lin kt vi nn t th thnh phn ti trng y ni

c xu hng lm xut hin ng sut ko di y mng.V vy y ta xc nh trng lng vt

liu dn vo khi chn sao cho tng ti trng thng ng hng xung s lm trit tiu thnh

phn ng sut ko di y mng do ti trng y ni gy nn.

- Chn loi vt liu dn bezit l c trng lng ring l 4.3 (T/m3).

- Trng lng vt liu dn cn thit m bo iu kin n nh c xc nh thng qua php

lp sao cho ng sut b nht di y mng min 0

min = -A

N

W

M

Trong :

N: ti trng thng ng tc ng ln y mng (giai on va thi cng xong)

N = Fbt + Ftt + Fvld Fdn

A: din tch y mng ca khi chn

A = 615.752 m2

W: momen khng un ca tit din y mng


33

W = 2155.133 m3

M: tng momen gy lt tc dng ln khi chn

M = Ms-dc + Mgi = 13557.297 + 4831.04 = 18388.34 (Tm)

Gvl N s (min) Kim tra

(T) (T) (T)

1425.79 0.00 -9.239 Khng TM

2500 1074.22 -7.494 Khng TM

3000 1574.22 -6.682 Khng TM

3500 2074.22 -5.870 Khng TM

4000 2574.22 -5.058 Khng TM

4500 3074.22 -4.246 Khng TM

5000 3574.22 -3.434 Khng TM

5500 4074.22 -2.622 Khng TM

6000 4574.22 -1.810 Khng TM

6500 5074.22 -0.998 Khng TM

7000 5574.22 -0.186 Khng TM

7500 6074.22 0.626 Tha mm

Ta chn trng lng vt liu dn l: 7500 (T).

II. TNH TON BI TON DAO NG RING

II.1. C s l thuyt

- Do cng trnh lm vic trong mi trng khc nghit, chu tc ng ca mi trng mang tnh

cht ng nn vic tnh ton lc tnh s khng y nh gi phn ng ca cng trnh. V

vy bi ton ng phi c xt n. Vic tnh dao ng ring ca cng trnh nhm mc ch

nh gi s nh hng ng do ti trng mi trng tc ng ln cng trnh.

- S tnh ca h c m t di dng mt thanh conson, lin kt gia h kt cu bn trn

vi mi trng t di y bin c coi l ngm. Khi lng c xem l tp trung ti cc

nt. Trong phm vi n, phng n c tnh ton cho t nht l 3 bc t do. nh gi phn

ng ng ca mi trng tc ng ln cng trnh ta phi gii bi ton dao ng ring ca kt

cu.

- Phng trnh vi phn c bn ca bi ton ng lc hc:

)(tFKUUCUM

Trong :

M: Ma trn khi lng (c k n khi lng nc km, h bm)


34

C: Ma trn vn tc

K: Ma trn cng ca kt cu trong h ta tng th

U : Vector gia tc ca kt cu trong h ta tng th

U : Vector vn tc ca kt cu trong h ta tng th

U: Vector chuyn v ca kt cu trong h ta tng th

- tm dao ng ring ca kt cu ta phi i gii phng trnh vi phn:

0

KUUCUM

II.2. Gii bi ton dao ng ring theo s gn ng

II.2.1. S tnh gn ng

- Khi chn c xem nh thanh conson c ngm ti y bin. Phn tr c coi nh

thanh c cng EJi , vi Ji l momen quan tnh tit din tr. Chia tr thnh 2 phn: c cng

EJ1 v EJ2

- Phn mng cng c coi nh mt thanh c cng EJ3 vi J3 l momen qun tnh tit

din mng, chiu di on ny bng chiu cao mng.

- Ton b khi lng khi chn , thng tng v khi lng nc km, h bm c quy v

thnh 3 khi lng tp trung:

Kt

cu

Tr on 1 on 2 on 3

Tit din (m) D = 7 D = 7 D = 28

t = 0.6 t = 0.6 t = 0.6

Chiu di (m) 18.5 18.5 11


35

II.2.2.Xc nh ma trn khi lng M

- Khi lng tp trung t ti nh tr M1: khi lng ti nh tr gm khi lng thng tng,

dm thng tng, khi lng 1 na on tr t M1 n M2, khi lng h bm, nc km

tnh vi su nc tnh ton l 33,5 m. Nhng 1 na tr t on M1 n M2 tr ln li khng

ngp nc nn s khng c khi lng h bm v nc km.

M1 =mtt + md + 0,5.m1-2

Trong :

mtt :khi lng thng tng

md :l khi lng dm thng tng

m1-2 :l khi lng on tr t m1 n m2

Khi lng

mtt(T) md (T) m1-2 (T) M1(T)

183.7 79.8 636.886 581.93

- Khi lng tp trung ti gia tr M2: gm 1 na khi lng on tr t M1 n M2, khi lng

nc km, h bm, 1 na khi lng on tr t M2 n M3:

M2 = 0,5.(m1-2 + m2-3) + mnk + mhb

M1

M2

M3

31

32

3323

22

21

13

12

11

F = 1

F = 1

F = 1

M3

M2

M1

M3

M2

M1


36

Trong :

m2-3 : khi lng on tr t M2 n M3

mhb : khi lng h bm

mnk : khi lng nc km

Khi lng m1-2 (T) m2-3(T) mnk(T) mhb(T) M2(T)

636.886 633.369 185.717 10.66 831.505

- mhb l khi lng h bm

- Khi lng tp trung ti mng M3: gm c khi lng mng, khi lng nc km, h

bm phn mng v 1 na khi lng tr t M2 n M3:

M3 = mnk + mhb + m + 0.5.m2-3

Trong :

m : khi lng mng

mhb : khi lng h bm

mnk : khi lng nc km

Khi lng m2-3(T) m(T) mnk(T) mhb(T) M3(T)

633.369 4442.31 1402.44 29.785 6191.22

- Ta c ma trn khi lng nh sau:

M =

591.21 0 0

0 844.673 0

0 0 6257.8

II.2.3.Xc nh ma trn cng

- Mmen qun tnh tit din ngang ca tr t M1 n M2 : tnh cho tit din vnh khuyn


37

J1 = 64

.(D0

4 Di

4) = 4 4

3.14.(7 5.8 )

64 = 62.27 (m4)

- Mmen qun tnh tit din ngang ca tr t M2 n M3 : tnh cho tit din vnh khuyn

J2 = 64

.(D0

4 Di

4) = 4 4

3.14.(7 5.8 )

64 = 62.27 (m

4)

- Mmen qun tnh tit din ngang ca mng:

J3 = 64

.(D0

4 Di

4) = 4 4

3.14.(28 27 )

64 = 4082.73 (m4)

- thun tin cho tnh ton ta tnh mmen qun tnh cho c khi chn :

1 2 3.18 .18 .11

47

J J JJ

1003.23 (m4)

II.2.4.Xc nh ma trn mm

- Ln lt cho cc lc bng 1 n v tc dng ti cc v tr t khi lng tp trung xc nh

cc chuyn v tng ng ca cc im khi lng.

- Bng cch nhn biu ta xc nh c cc ij, t ta s lp c ma trn mm

11 = 17,27.10-5

(m/T) 12 = 2,31.10-5

(m/T) 13 = 1,94.10-7

(m/T)

21 = 2,31.10-5

(m/T) 22 = 9,37.10-6

(m/T) 23 = 1,13.10-7

(m/T)

31 = 1,94.10-7

(m/T) 32 = 1,13.10-7

(m/T) 33 = 3,29.10-8

(m/T)

18

00

01

80

00

P=1

P=1

P=1

M2=29(T.m) M3=11(T.m)M1=47(T.m)

18(T.m)36(T.m)

18(T.m)

11

00

0


38

Vy ma trn mm l :

D = 10-5

.

17,27 2,31 0,019

2,31 0,937 0,013

0,019 0,013 0,00329

( m/T)

II.2.5.Tnh dao ng ring

- Phng trnh c trng ca dao ng ring :

K M | =0

- Thay s vo nh sau:

591,21 0 0

0 844,673 0

0 0 6257,8

- .= 10-5

.

17,27 2,31 0,019

2,31 0,937 0,013

0,019 0,013 0,00329

= 0

- Khi ta tm c tn s dao ng ring, chu k dao ng ring ca h nh sau:

1 = 1 = 66.79(rad/s) T1 = 0.094s

2= 2 = 42.39(rad/s) T2 = 0.0148s

3= 3 = 28.804(rad/s) T3 = 0.218s

II.3. Gii bi ton dao ng ring theo s tng th (thc) ca cng trnh

- Ta gii bi ton dao ng ring theo phng php phn t hu hn.

- Cc cu kin c m t nh sau: Tr c m t l phn t shell, cc vch cng l phn t

shell, phn khi bao gm cc phn t shell, cc phn t frame cng c m t n gin l

cc phn t thanh mc d v nguyn tc phn t tr c phi c m t l phn t khi.

- Sau khi nhp s liu vo Sap2000 ta tnh c chu k dao ng ring ca khi chn l: T=

0.5 (s)

III. XC NH H S k

- Nu chu k dao ng ring ln nht ca cng trnh nh hn rt nhiu so vi chu k ti trng

(TDR< 3sec ) th lc ny nh hng ng l nh. Bi ton lc ny c xt nh bi ton ta

tnh, vic nh gi s b nh hng tnh cht ng ca cc tc ng s c xt qua h s ng

(k) :

.

..2

1

1

22

t

o

U

Uk


39

Trong :

Uo: bin ca chuyn v ng

Ut: chuyn v cc i do tc dng tnh ca ti trng gy ra

: tn s ca dao ng ring ng vi dng dao ng ring th 1

: H s gim chn. Thng chn

= 0.05 0.1 (5% - 10% h s gim chn ti hn.

H s gim chn ti hn

=1

: tn s vng ca sng tc dng.

: thng s a vo tnh ton. Chn = 0.5M

C

- Nu chu k dao ng ring ca cng trnh gn vi chu k ti trng tc ng ( y l chu k

ca sng) th nh hng ca ti trng ng n phn ng ca cng trnh l ng k. Lc ny phi

tnh ton ng kt cu.

- Kt lun: Chu k tnh ton ca kt cu chn nh hn 3s nn khng phi xem xt nh hng

ng trong qu trnh tnh ton m gii bi ton theo phng php ta tnh, trong h s ng

lc hc c tnh nh sau:

.

..2

1

1

22

t

od

U

Uk

= 0.439 rad/s

= 12.566 rad/s

= 0.08

==> k = 1.000595

Nh vy: Kt qu ni lc trong phn t kt cu ca h s nhn vi h s k s dng tnh ton.

IV. T HP TI TRNG

- Trong cng mt thi im, cng trnh c th chu nhm cc t hp ti trng khc nhau tc

dng ln n, iu ny ph thuc vo tng loi ti trng trong nhm, tng loi ti trng da vo

cc kh nng xy ra ng thi hay khng ng thi ca cc ti trng. Da trn nh gi tin

cy ngi ta a ra cc t hp ti trng:

+ Cc t hp trong iu kin bin cc hn:

Cc t hp ny bao gm cc trng hp ti trng: Ti trng c nh, ti trng tm thi,

ti trng thy tnh v nu cn th phi xt c ti trng do bin dng.

+ Cc t hp ti trng vn hnh:

Phi xc nh c iu kin bin cc hn ca mi trng cho php cng trnh vn

hnh t hp cng ti c nh, ti tm thi, ti thy tnh, ti trng do bin dng.

+ T hp ti trng khi c s c:


40

Cc ti trng do s c phi c t hp cng vi ti c nh, ti tm thi, ti thy tnh,

nu cn phi xt n ti trng do bin dng cng ti trng mi trng v ti trng vn hnh

tng ng.

- Trong n thit k nhm xt t hp ti trng trong giai on khai thc:

Combo

Loi ti trng H s

Ti trng bn thn 1

Ti trng thng tng 1

Ti trng sng v dng chy NE 0.9

Ti trng gi NE 0.9

Ti trng h bm 1

Ti trng y ni 1

Ti trng nc km 1

Ti trng vt liu dn 1

p lc thy tnh 1

NI DUNG TH 3

XC NH NI LC, CHUYN V

I. XY DNG S TNH CHO KHI CHN

I.1. M hnh ha kt cu khi chn theo phng php phn t hu hn

- Kt cu chn cng trnh bin trng lc b tng c ri rc ha theo phng php phn t

hu hn vi cc loi phn t v, phn t khi v cc phn t thanh.

- Trong phm vi n, nhm em s dng phn mm Sap2000v14 m hnh ha kt cu

+ Tr , bn y, bn thnh, bn np c m t l cc phn t SHELL

+ Dm chnh, dm ph, dm vng, ct c m t l cc phn t FRAME


41

S tng th khi chn

I.2. M hnh ha ti trng theo phng php phn t hu hn

- Ti trng sng tc dng xc nh theo cng thc Morisson l ti trng tp trung t ti trc

thanh, ti trng thng tng, ti trng gicng thng l ti trng tp trung. Khi tnh ton kt

cu bng phn mm Sap2000, cn thit phi a cc ti trng nu trn v nt ca li phn t

hu hn.

I.2.1. M hnh ha ti trng thng tng

- Mt cch gn ng c th coi ti trng thng tng thng qua sn thng tng phn b u

ln mt tip xc gia kt cu thng tng v mt trn ca tr . Khi ti trng quy v nt

c tnh theo cng thc

gi = n

G

Trong :

G: tng ti trng thng tng

G = 183.7 (T)

gi: ti trng thng tng chia v nt th i ca li phn t hu hn ti mt tip xc gia

tr vi kt cu thng tng

n: tng s nt trn thnh bin tr ti mt tip xc gia tr vi kt cu thng

tng

Ti trng (T) n gi (T)


42

183.7 16 11.48

I.2.2. M hnh ha ti trng gi

- Ti trng gi c th a v nt ca li phn t hu hn theo cng thc

Pi = n

P

Trong :

P: tng ti trng gi xc nh theo quy phm

Pi: ti trng gi chia v nt th i ca li phn t hu hn

n: tng s nt theo chu vi tr

- Bng nhp phn ti trng gi tc dng ln phn tr khng ngp nc:

z(so vi dtt) P (T) Pi (T)

0 0.000 0

1 0.789 0.0493107

2 0.906 0.0566431

3 0.983 0.0614279

4 1.041 0.0650659


43

5 1.089 0.0680355

6 1.129 0.0705621

7 1.164 0.0727714

8 1.196 0.0747411

9 1.224 0.0765226

10 1.250 0.0781522

11 1.274 0.0796562

12 1.297 0.0810546

13.5 1.328 0.0829866

- Bng nhp v quy i ti trng gi tc dng ln thng tng v nt trn thnh bin tr ti

mt tip xc gia tr vi kt cu thng tng

Lc gi

(T) Momen(T.m)

M nt(T.m)

81.732 290.609 4.036232815

I.2.3. M hnh ha ti trng sng v dng chy

- i vi cc tr c kch thc nh, ti trng sng tc dng ln tr c xc nh theo

cng thc Morisson l lc tp trung t ti trc thanh. Mt cch gn ng c th coi lc ngang

do sng v dng chy tc ng ln tr c phn b u trn chu vi ca tr . Khi lc


44

ngang ti nt th i c xc nh nh sau

qi = n

Q

Trong :

Q: ti trng ngang ti cao trnh th i c xc nh theo cng thc Morisson

qi: ti trng ngang chia v nt th i ca li phn t hu hn trn bin ca tr ti cao

trnh th i

n: tng s nt trn thnh bin ca tr ti cao trnh i

- Bng nhp ti trng sng v dng chy quy v nt:

nt Fx Fix Fy Fiy Fz Fiz

0 71.784271 4.487 -0.075 -0.005 0 0.000

1 143.58984 8.974 -0.158 -0.010 0.002767 0.000

2 143.63276 8.977 -0.175 -0.011 0.0138414 0.000

3 143.67628 8.980 -0.194 -0.012 0.036016 0.001

4 143.72029 8.983 -0.213 -0.013 0.0693423 0.001

5 143.76467 8.985 -0.234 -0.015 0.1138972 0.002

6 143.8093 8.988 -0.255 -0.016 0.1697836 0.002

7 143.85405 8.991 -0.278 -0.017 0.2371293 0.003

8 143.8988 8.994 -0.301 -0.019 0.3160875 0.004

9 143.94341 8.996 -0.325 -0.020 0.4068363 0.006

10 143.98773 8.999 -0.350 -0.022 0.5095784 0.007

11 72.026714 4.502 -0.376 -0.023 0.6245406 0.009

12 4.6024876 0.288 -0.052 -0.003 0.4449083 0.006

13 9.2102396 0.576 -0.108 -0.007 0.2230374 0.003

14 9.220641 0.576 -0.115 -0.007 0.2613414 0.004

15 9.2307642 0.577 -0.122 -0.008 0.3029843 0.004

16 9.2405615 0.578 -0.130 -0.008 0.3480506 0.005

17 9.2499831 0.578 -0.138 -0.009 0.3966289 0.006

18 9.258977 0.579 -0.146 -0.009 0.4488125 0.006

19 9.2674887 0.579 -0.154 -0.010 0.5046984 0.007

20 9.2754618 0.580 -0.163 -0.010 0.5643866 0.008

21 9.2828377 0.580 -0.172 -0.011 0.6279797 0.009


45

22 9.2895558 0.581 -0.181 -0.011 0.6955824 0.010

23 9.2955537 0.581 -0.190 -0.012 0.7672996 0.011

24 9.3007674 0.581 -0.200 -0.012 0.8432365 0.012

25 9.3051315 0.582 -0.209 -0.013 0.9234966 0.013

26 9.3085797 0.582 -0.219 -0.014 1.0081804 0.014

27 9.3110451 0.582 -0.230 -0.014 1.097384 0.015

28 9.3124607 0.582 -0.240 -0.015 1.191197 0.017

29 9.31276 0.582 -0.251 -0.016 1.2897005 0.018

30 9.3118778 0.582 -0.262 -0.016 1.3929643 0.019

31 9.309751 0.582 -0.273 -0.017 1.5010447 0.021

32 9.3063196 0.582 -0.284 -0.018 1.6139806 0.022

33 9.3015278 0.581 -0.296 -0.019 1.7317907 0.024

34 9.2910615 0.581 -0.305 -0.019 1.8544688 0.026

I.2.4. M hnh ha p lc thy tnh

- p lc thy tnh c a v nt ca li phn t hu hn di dng cc lc tp trung vi tr

s tng ng vi p lc trn din tch c lc tp trung thay th


46

I.2.5. M hnh ha ti trng h bm, nc km

- Ti trng h bm, nc km c th a v nt ca li phn t hu hn theo cng thc

Pi = n

P

Trong :

P: tng ti trng h bm, nc km ti cao trnh th i

Pi: ti trng h bm, nc km chia v nt th i ca li phn t hu hn trn bin tr

ti cao trnh th i

n: tng s nt trn thnh bin tr ti cao trnh th i

- Bng tnh ton nhp ti trng v nt li:

Loi

k/c

K.l

h.bm

K.l

n.km z(m) s nt K.l v nt

(t) (t) H.bm(t) N.km(t)

Tr 10.65938 185.7173 33.5 16 0.0306 0.516

33 16 0.0306 0.516

32 16 0.0306 0.516

31 16 0.0306 0.516

30 16 0.0306 0.516

29 16 0.0333 0.516

28 16 0.0333 0.516

27 16 0.0333 0.516

26 16 0.0333 0.516

25 16 0.0333 0.516

24 16 0.0383 0.516

23 16 0.0383 0.516


47

22 16 0.0383 0.516

21 16 0.0267 0.516

20 16 0.0267 0.516

19 16 0.0267 0.516

18 16 0.0267 0.516

17 16 0.0267 0.516

16 16 0.0267 0.516

15 16 0.0267 0.516

14 16 0.0267 0.516

13 16 0.0267 0.516

12 16 0.0267 0.516

Khi

29.78547 1402.441 11 192 0.0579 7.968

10 16 0.1061 7.968

9 16 0.1061 7.968

8 16 0.1061 7.968

7 16 0.1061 7.968

6 16 0.1061 7.968

5 16 0.1061 7.968

4 16 0.1061 7.968

3 16 0.1061 7.968

2 16 0.1061 7.968

1 16 0.1061 7.968

Sum 40.44485 1588.158

I.2.6. M hnh ha nn t

- Ta dng cc lin kt SPRING m t cc l xo lin kt mng vi nn.

a) b)


48

S tnh kt cu lin kt mm vi nn ti y mng,

Mng khng tuyt i cng

a) Mt y mng

b) Lin lt l x ti cc nt

- cng cc lin kt l x c xc nh theo ln n v ca mng, bng thng s ca

lc n v trn chuyn v ca l x di tc dng ca lc n v. Chuyn v ca l xo lin kt

gia y mng vi t nn di mng c th c xc nh theo ln c ca mng

di tc dng ca ngoi lc ln cng trnh.

- Tnh ln mng trng lc theo s liu a cht ti ni xy dng cng trnh

+ Chuyn y mng hnh trn v hnh vung c din tch tng ng

Mng trn Mng vung

knh(m) Din tch Cnh

(m)

Din

tch

28 615.752 24.814 615.752

+ Bng tnh ln theo mng vung tng ng:

im Lp t hi z l/b z/b Ko bt Sgl Eo S, cm

1 1 0 0 1 0 1 0 9.86471 2024 0

2 1 1 1 1 0.040322581 0.9835 1.685 9.70194 2024 0.27323

3 1 1 2 1 0.080645161 0.9671 3.37 9.54016 2024 0.26867

4 1 1 3 1 0.120967742 0.9506 5.055 9.37739 2024 0.26409

5 1 1 4 1 0.161290323 0.9342 6.74 9.21561 2024 0.25953

6 1 1 5 1 0.201612903 0.9177 8.425 9.05284 2024 0.25495

7 1 1 6 1 0.241935484 0.9013 10.11 8.89106 2024 0.25039

8 1 1 7 1 0.282258065 0.8719 11.795 8.60104 2024 0.24222

9 1 1 8 1 0.322580645 0.8393 13.48 8.27945 2024 0.23317

10 1 1 9 1 0.362903226 0.8068 15.165 7.95885 2024 0.22414

11 1 1 10 1 0.403225806 0.7742 16.85 7.63726 2024 0.21508

12 2 1 11 1 0.443548387 0.7416 18.525 7.31567 1756 0.23747

13 2 1 12 1 0.483870968 0.709 20.2 6.99408 1756 0.22703

14 2 1 13 1 0.524193548 0.681 21.875 6.71787 1756 0.21806

15 2 1 14 1 0.564516129 0.656 23.55 6.47125 1756 0.21006

16 2 1 15 1 0.60483871 0.631 25.225 6.22463 1756 0.20205

17 2 1 16 1 0.64516129 0.606 26.9 5.97801 1756 0.19405

18 2 1 17 1 0.685483871 0.581 28.575 5.7314 1756 0.18604

19 2 1 18 1 0.725806452 0.556 30.25 5.48478 1756 0.17804

20 2 1 19 1 0.766129032 0.531 31.925 5.23816 1756 0.17003

21 2 1 20 1 0.806451613 0.506 33.6 4.99154 1756 0.16203


49

22 2 1 21 1 0.846774194 0.481 35.275 4.74492 1756 0.15402

23 2 1 22 1 0.887096774 0.456 36.95 4.49831 1756 0.14602

S= 3.58013

Tng ln ca mng l: S = 3.58 cm < [S] = 8 cm

- Xc nh tng cng ca l x lin kt bng cch ly tng lc tc dng chia cho ln tng

cng ca mng theo d bo trn

K = S

P

Trong :

K: tng cng l xo lin kt

P: lc dc trc gy ln

S: tng ln ca mng theo d bo

=> K = 6074.22

0.0358= 169664.75 (T/m)

- Xc nh cng ca cc l xo phn b: vi gii thit mng ln u, cng cc l xo phn

b c tnh theo din tch thay th ca l xo

cng ca 1 l xo c tnh nh sau:

ki = A

AK i.

Trong :

K: tng cng l xo lin kt (T/m)

ki: cng l xo th i

A: din tch y mng

Ai: din tch thay th l xo th i

S tng th y mng Din tch thay th 1 l xo

Bn knh

R(m)

S l

xo Ai,m2 ki,T/m

14 16 2.651 730.381


50

13 16 5.105 1406.659

12 16 4.712 1298.455

11 16 4.320 1190.250

10 16 3.927 1082.046

8.75 16 3.099 853.802

8 16 2.706 745.597

7 16 2.749 757.432

6 16 2.356 649.227

5 16 1.963 541.023

4 16 1.571 432.818

3.5 16 1.890 520.734

Bn knh

R(m)

S l

xo

Vng

ngoi Vng trong DT 1 Pt

14 16 28 26 5.301

13 16 26 24 4.909

12 16 24 22 4.516

11 16 22 20 4.123

10 16 20 18 3.731

8.75 16 17.5 16 2.467

8 16 16 14 2.945

7 16 14 12 2.553

6 16 12 10 2.160

5 16 10 8 1.767

4 16 8 6 1.374

3.5 16 7 0 2.405

II. XC NH NI LC CHO CC CU KIN TR V

- Sau khi ri rc kt cu, ti trng, nn t theo phng php phn t hu hn nh trnh by

cc mc trn, ta s dng phn mm Sap2000 tnh ton ng thi kt cu chn cng trnh

vi nn. Cc bc tnh ton ng thi kt cu khi chn vi nn:

+ Bc 1: Nhp s tnh, s dng cc phn t SHELL v lin kt SPRING m hnh

ha kt cu

+ Bc 2: Tnh ton ng sut ca cc l xo

+ Bc 3: Loi b cc l xo c ng sut dng (chu ko)

+ Bc 4: Tnh ton li, lp li bc 2 v 3 cho n khi khng cn l xo b ko na

- Bng ni lc cc cu kin:


51

Bng thng k ni lc bn

Cu Kin F11 F22 F12 M11 M22 M12

(T/m) (T/m) (T/m) (T-m/m) (T-m/m) (T/m)

Bn Np Max -30.133 -27.36 10.582 21.75 17.3403 11.4537

Min -56.837 -49.356 -13.144 -25.31 -14.52 -11.5842

Bn y Max 115.136 85.285 35.569 28.33 27.21 27.3892

Min -70.123 -55.687 -50.3 -15.8 -4.54 -31.6169

Bn Thnh Max 9.735 48.675 90.897 8.6647 21.34825 1.91375

Min -297.668 -69.575 -90.759 -13.47 -16.77 -1.91399

Vch Cng 1 Max -33.067 -38.491 5.619 34.167 7.68073 14.6651

Min -51.063 -45.454 -5.553 -49.942 -20.60429 -15.4562

Vch Cng 2-6 Max 3.901 5.74 2.885 0.6007 1.27888 0.28522

Min -25.758 -29.733 -2.884 -0.7189 -1.48748 -0.28524

Bng thng k ni lc dm - ct

Cu kin P (T) V2 (T) M3 (T-m)

DM VNG

NP Max -29.9582 1.4271 2.1468

Min -48.2739 -1.4183 -2.767

Y Max 34.5222 7.6599 50.695

Min -29.5984 -7.6636 24.453

THNH Max -498.0098 1.2871 1.7437

Min -563.3296 -1.2846 -5.293

DM BO

NP Max -39.1367 1.3976 10.504

Min -82.9827 -1.3932 2.7714

Y Max 82.3795 2.9007 55.617

Min -103.9592 -2.7235 31.117

DM PH

NP Max -31.1066 45.7261 72.189

Min -39.4591 -44.3022 -106.72

Y Max -11.236 19.7046 100.43

Min -41.9997 -53.1295 -90.079

DM CHNH

NP Max -58.8972 125.065 160.26

Min -85.7614 -112.085 -254.76

Y Max -0.9424 35.7475 295.65

Min -138.3097 -125.555 -284.19

CT CHNG TRONG

Max -290.2611 0.6623 4.3464

Min -317.9378 -0.7057 -4.4283

BIN Max 90.0115 58.0636 74.3


52

Min -68.3274 -80.958 -195.75

DM TT Max 6.310 18.450 53.540

Min -0.540 -24.190 -74.620

- Biu momen cc cu kin

1. DM CHNH NP

2. DM PH NP

3. DM BO NP.

4. DM VNG TRONG NP


53

5. DM CHNH Y

6. DM PH Y

7. DM BO Y

8. DM VNG Y


54

9. DM VNG THNH

BIU NI LC CA BN

1. BN NP

-70.58

26.43

-36.52

37.6

-52.7

M 1-1

-69.54

24.937.89

-23.3

M 2-2


55

2. BN Y

3. BN THNH

M 1-1

-44.89

-6.9

-89.4

-48.4

56.68

M 2-2

-45.7

-7.8

-93.5

-50.3

58.2

-4.1-2.84

-31.75

4.68.3

M 1-1

-8.61

-3.2

-47.5

10.05

27.2M 2-2


56

NI DUNG TH 4

THIT K CU KIN TR

1. Tnh ton b tr c thp ST cho tr.

1.1. Tnh ton ct thp ST cho tr.

iu kin ban u:

- Thp ng sut trc khai thc trong giai on n hi.

- B tng ng sut trc khng nt.

a

a

M

N Q N

M

Q a

a

1

1

1-1

a

a

1-1

Cu kin lm vic trong min n hi, ng sut tng cng trn tit din :

F

A*

F

N

J

a*M ss

Trong :

M: mmen ti tit din.

N: lc dc ti tit din.

J: mmen qun tnh ca tit din.

a: khong cch t trc cu kin ti mp ngoi ca tit din vnh khuyn.

Hnh 2: S tnh dm b tng ct thp ng sut tr-c.


57

F: din tch mt ct ngang tit din.

s : ng sut hiu dng trong thp ng sut trc.

As: din tch thp ng sut trc.

iu kin b tng khng chu ko khng xut hin vt nt:

0F

A*

F

N

J

a*M ss

F*F

N

J

a*MA ss

= k.F

y k ng sut gy ko.

T phng trnh trn ta chn trc ng sut trc trong ct thp, thng ly s80% cng

tiu chun ca thp ng sut trc, t c th tnh c din tch ct thp ng sut trc trc

As ng vi s chn.

Vic la chn s (ri tnh c As) phi i km vi iu kin m bo bn vng nn

ca tit din v b tng khng c xy ra vt nt.

Bng cc thng s k thut v thp ng sut trc ASTM A416:

S liu u vo:

- ng knh tr trn: D = 7 m, chiu dy t =0.6 m.

- Tr di c D = 7 m, chiu dy t = 0.8 m.

- Thp cng cao: Chn thp ng lc trc ASTM A416.

(Chn b thp ng lc trc loi 7 si c 12.7 mm, tm hiu VINACONEX Xun Mai)

Si thp loi ASTM A416 c cc c tnh:

- ng knh danh nh: 12.7 mm

- Din tch danh nh: 98.71 mm2


58

- Gii hn bn : fb= 186000 T/m2

- Lc ko t nh nht: 18.37 T

B tng Mc 500 c cng chu nn ti hn l: c = 2150 T/m2

y chn s = 148800 T/m2 tnh ton.

Bng kt qu tnh ton thp ng sut trc cho tr:

Z (m) k ( T/m2 ) F (m

2 ) s.As (T) s (T/m

2) As (cm

2) n

0 - 6 6.2 15.5823 96.61 148800 9.87 0.658

6 - 10 63.5 15.5823 989.476 148800 9.87 6.737

10 - 17 283.5 12.0637 3420.063 148800 9.87 23.287

17 - 23 222.23 12.0637 2680.92 148800 9.87 18.254

23 - 29 114.8 12.0637 1384.915 148800 9.87 9.43

29 - 35 30.97 12.0637 373.613 148800 9.87 2.544

35 - 41 30.5 12.0637 367.943 148800 9.87 2.505

41 - 47 67.98 12.0637 820.091 148800 9.87 5.584

Trong : n S b thp cn thit mi on tr, trong phm vi n ta lm trn ln b tr

thun tin.

Kim tra s b iu kin m bo bn vng nn ca tit din:

Ta c ng sut nn cc i trong b tng nh sau:

* ** s s s s

b n

A AM a N

J F F F

ng sut nn b phi tha mn iu kin:

b 0.45 * c vi cu kin chu nn ng tm.

b 0. 5 * c vi cu kin chu nn lch tm( Chng ta cn tnh cho trng hp

ny).

Trong c l cng chu nn ti hn ca b tng.


59

Bng kt qu tnh ton kim tra

Z (m) n ( T/m2 ) F (m

2 ) s.As (T) b (T/m

2) 0,5Rc Kt lun

0 - 6 -390 15.5823 96.610 -396.2 1075 TM

6 - 10 -390 15.5823 989.476 -453.5 1075 TM

10 - 17 -352 12.0637 3420.063 -635.5 1075 TM

17 - 23 -113.16 12.0637 2680.92 -335.39 1075 TM

23 - 29 -80.96 12.0637 1384.915 -195.76 1075 TM

29 - 35 -64.89 12.0637 373.613 -95.86 1075 TM

35 - 41 -63 12.0637 367.943 -93.5 1075 TM

41 - 47 -131.6 12.0637 820.091 -199.58 1075 TM

+/ Nhn xt: Ta thy trn on tr v tr di b tng kh nng chu nn nn ta khng cn

b tr thp thng chu nn cng b tng.

1.2. B tr ct thp ST cho tr.

- Thp ng sut trc chn l cc b thp bao gm 7 si c bn dng xon kiu dy

cp, ng knh mi si l 12.7 mm. Din tch tit din ca mt b thp ST l 9.87 cm2.

- Da vo gi tr din tch thp ng sut trc yu cu ta tnh c s lng b thp cn

thit ti cc cao trnh. Nh trnh by trn, ta s lm trn s lng b thp ln d b tr.

Ta thy din tch ca 1 b thp l S = 9.87 cm2 => ng knh ng ghen ti thiu cha

c b thp trn l D = 3.36 cm.

Tham kho catalog ca Cng ty C phn Vt t Thit b Cng trnh Minh c ta chn loi

ng ghen c ng knh trong l: d = 60mm, dy l 0.3mm.

Sau khi chn ta c bng b tr ct thp nh sau:

Z (m) n Fghen (cm2 ) As (cm

2) s (T/m

2)

0 - 6 2 35.2565 19.74 48941.366

6 - 10 7 35.2565 69.09 143215.519

10- 17 24 35.2565 236.88 144379.577

17 - 23 19 35.2565 187.53 142959.503

23 - 29 10 35.2565 98.7 140315.560

29 - 35 3 35.2565 29.61 126178.074

35 - 41 3 35.2565 29.61 124263.199

41 - 47 6 35.2565 59.22 138482.168


60

1.3. Xc nh cc hao tn ng sut trc.

ng knh trong 30 35 40 45 50 55 60 65 70

Dung sai 0.5

dy tiu chun

ca thp 0.25 0.3

ng knh trong 105 110 115 120 125 130 135 140 150

Dung sai 1.0

dy tiu chun

ca thp 0.3 -

ng knh trong 30 50 55 60

S l tiu chun Cp 15 1 24 5 -

Cp 13 1 25 - 68

ng knh trong 100 105 120 130

S l tiu chun Cp 15 1819 - 2127 31

Cp 13 2527 31 3437 4344

ng knh trong 75 80 85 90 95 100

Dung sai 0.5 1.0

dy tiu chun ca

thp 0.3

ng knh trong 160 180 200 220 240 280

Dung sai 1.0

dy tiu chun ca

thp -

ng knh trong 70 80 90

S l tiu chun Cp 15 67 89 1017

Cp 13 9 1014 1522

ng knh trong 140 160

S l tiu chun Cp 15 3437 4355

Cp 13 5455 -


61

i vi cc cng trnh bin trng lc b tng, khng dng kt cu b tng lp ghp, thng

to ng sut trc bng phng php cng sau, cng trn b tng, cc hao tn c tnh nh sau:

- Nhm cc hao tn xy ra trong qu trnh ch to: ht1 = neo + ms

- Nhm cc hao tn xy ra trong qu trnh khai thc: ht2 = ch + co + fb

a) Hao tn do bin dng ca neo t thit b cng

2( / )neo aE T m

L

Trong :

: tng bin dng ca bn thn neo c xc nh bng thc nghim. Nu khng

c s liu thc nghim c th ly = 2 (mm).

Ea: mun n hi ca vt liu lm neo, Ea = 2x107 (T/m

2), ly bng thp cng

cao.

L: chiu di b tho c cng (mm).

Bng kt qu tnh ton:

Z (m) L (mm) neo (T/m2)

0 - 6 6000 7000

6 - 10 4000 10500

10 - 17 7000 6000

17 - 23 6000 7000

23 - 29 6000 7000

29 - 35 6000 7000

35 - 41 6000 7000

41 - 47 6000 7000

b) Hao tn do ma st ca ct thp

211 ( / )ms s kx T me


62

Trong : e c s logarit t nhin.

k: h s tra bng, ph thuc vo b mt tip xc, k = 0.003

: h s ma st gia ct thp v thnh ng, = 0.35 (thp si).

x: chiu di ct thp t thit b cng n tit din tnh ton.

: tng gc quay ca tit din tnh ton, = 0

s: ng sut trong b thp ng sut trc khng k n cc hao tn ng sut.

Bng kt qu tnh ton:

Z (m) s x ms

0 - 6 48941.366 6 873.063

6 - 10 143215.519 4 1708.316

10 - 17 144379.577 7 3000.357

17 - 23 142959.503 6 2550.25

23 - 29 140315.56 6 2503.085

29 - 35 126178.074 6 2250.887

35 - 41 124263.199 6 2216.727

41 - 47 138482.168 6 2470.379

c) Hao tn do hin tng chng ng sut khi cng c gii

sac

s

chR

)1.022.0(

Trong :

s : ng sut trong b thp ng sut trc (T/m2)

Rac: Cng tiu chun ca thp ng sut trc tnh bng (T/m2)

Bng kt qu tnh ton:

Z (m) s Rac ch

0 - 6 48941.366 186000 -2061.037

6 - 10 143215.519 186000 9938.398

10 - 17 144379.577 186000 10217.965

17 - 23 142959.503 186000 9877.342

23 - 29 140315.56 186000 9255.865


63

29 - 35 126178.074 186000 6213.372

35 - 41 124263.199 186000 5837.634

41 - 47 138482.168 186000 8834.624

d) Hao tn do co ngt ca b tng

B tng s dng Mc 500 c hao tn do co ngt l co = 3500 T/m2

e) Hao tn do t bin ca b tng

0

..20000R

k btb

(T/m2) khi 6.00

R

b

0

40000. .( 0.3)btbn kR

(T/m2) khi 6.0

0

R

b

Trong :

- k =1 : h s ng cng t nhin.

- Ro: cng khi vung b tng lc bung ct thp,

Ro = 2150 T/m2

- b: ng sut nn trong b tng ti mc ct thp cng k n cc hao tn trn

(h = neo + ms + ch + co ).

. s s h s s s h s

b N

A A A AM a N

j A A A

Bng tnh ton c th:

Z (m) n(T/m2) s(T/m

2) h(T/m

2) As(m

2) b(T/m

2) tb(T/m

2)

0 - 6 -390 48941.366 11373.063 0.002 -389 -3614.505

6 - 10 -390 143215.519 25646.714 0.0069 -379 -3522.126

10 - 17 -352 144379.577 22718.323 0.0237 -307 -2859.450

17 - 23 -113.16 142959.503 22927.592 0.0188 -78 -721.108

23 - 29 -80.96 140315.560 22258.95 0.0099 -63 -583.709

29 - 35 -64.89 126178.074 18964.259 0.003 -60 -560.328

35 - 41 -63.00 124263.199 18554.361 0.00. -58 -543.683

41 - 47 -131.600 138482.168 21805.003 0.0059 -121 -1124.615


64

f) Tng hp cc hao tn ng sut trc

- Hao tn tng cng trong c 2 giai on: ht = ht1 + ht2

- Gi tr ng sut ko cng khi thi cng l: = s + ht

Z (m) s(T/m2) ht1(T/m

2) ht2(T/m

2) (T/m

2)

0 - 6 48941.3664 7873.063 7114.505 63928.934

6 - 10 143215.5192 12208.316 16960.524 172384.359

10 - 17 144379.5773 9000.357 16577.416 169957.350

17 - 23 142959.5030 9550.250 14098.450 166608.203

23 29 140315.5595 9503.085 13339.574 163158.219

29 - 35 126178.0743 9250.887 10273.7 145702.661

35 - 41 124263.1988 9216.727 9881.316 143361.242

41 - 47 138482.1681 9470.379 13459.239 161411.786

1.4. Kim tra li cc tr BTCT ng sut trc

a) Tnh li cc c trng tit din

Din tch tit din tr i phn gim yu t do ng ghen cha thp ST chim ch:

Fhd = Fbt Fghen

Trong :

Fbt: din tch mt ct ngang tit din BTCT.

Fghen: tng din tch ng ghen trong tit din.

Bng tnh ton c th nh sau:

Z (m) Fbt(m2) Fghen(m

2) Fh(m

2)

0 - 6 15.5823 0.0035 15.5752

6 - 10 15.5823 0.0035 15.5576

10 - 17 12.0637 0.0035 11.9791

17 - 23 12.0637 0.0035 11.9967

23 - 29 12.0637 0.0035 12.0285

29 - 35 12.0637 0.0035 12.0531

35 - 41 12.0637 0.0035 12.0531


65

41 - 47 12.0637 0.0035 12.0426

b) Kim tra li ng sut nn trong b tng c k n cc hao tn ng sut trc trn tit din

gim yu

( ). .s h s s

b n

hd hd hd hd

A AM N

J F F F

iu kin : b < 0.5C ( Tit din chu nn lch tm)

C : Cng chu nn ti hn ca B Tng.

Kt qu kim tra nh sau:

Z (m) n(T/m2) (T/m

2) As(m

2) Fhd(m

2) b(T/m

2) 0,5.Rc Kt lun

0 - 6 -390 63928.93 0.002 15.5752 -398.102 1075 TM

6 - 10 -390 172384.36 0.0069 15.5576 -466.554 1075 TM

10 - 17 -352 169957.35 0.0237 11.9791 -688.081 1075 TM

17 - 23 -113.16 166608.20 0.0188 11.9967 -373.598 1075 TM

23 - 29 -80.96 163158.22 0.0099 12.0285 -214.840 1075 TM

29 - 35 -64.89 145702.66 0.003 12.0531 -100.684 1075 TM

35 - 41 -63 143361.24 0.003 12.0531 -98.218 1075 TM

41 - 47 -131.6 161411.79 0.0059 12.0426 -210.975 1075 TM

c) Kim tra iu kin khng xy ra vt nt xin

Ta c ng sut tip:

t2J

QS

Trong :

S: mmen tnh 3231 RR3

2S

R1, R2 : bn knh ngoi v trong ca tit din vnh khuyn

t: dy ca tit din vnh khuyn


66

J: Mmen qun tnh.

Q: lc ct ti tit din

y = S23

ng sut php cc i trn mt ct tr;

. s

N

hd

A

F

ng sut ko chnh:

2

2

122

Kim tra iu kin khng nt( khng xy ra vt nt xin)

nR33.01

Bng kt qu tnh ton

Z (m) (T/m2) (T/m2) 1(T/m2) 0.33 nR (T/m

2) Kt lun

0 - 6 9.8 -398.1023 0.0603 15.3015 Tha mn

6 - 10 133.2 -466.5544 8.8375 15.3015 Tha mn

10 - 17 133.2 -688.0811 6.2213 15.3015 Tha mn

17 - 23 26.79 -373.5980 0.4778 15.3015 Tha mn

23 - 29 18.00 -214.8401 0.3744 15.3015 Tha mn

29 - 35 9.17 -100.6836 0.2071 15.3015 Tha mn

35 - 41 2.00 -98.2184 0.0102 15.3015 Tha mn

41 - 47 34.37 -210.9752 1.3645 15.3015 Tha mn

Tnh ton ct thp ai


67

Theo tnh ton kim tra trnt th trn ton b tr khng xy ra vt nt xin, do ta t ct

thp ai theo cu to. t 4 lp ct ai 10 a200 theo b dy ca tit din tr.

3. Tnh ton b tr ct thp cho dm tr thng tng.

Ti trng do thng tng tc dng ln 1 dm l: Q =

= 45.925 (T).

Dm c tit din: bxhxl = 0.5x1x12 (m) => Ti trng bn thn dm: 15T

Coi ti trng thng tng tc dng phn b u trn dm, ta tnh c ti trng do tc dng

ln 1m di ca dm:

45.925 15

5.1( / )12

q T m

S tnh v biu ni lc nh hnh v:

S tnh

3500 7000 3500

3500 7000 3500


68

Biu m men

Biu lc ct

Ni lc tnh ton ct thp dm thng tng:

M = 22.95 (Tm)

Q = 15.3 (T)

a) Tnh ton ct thp dc dm thng tng.

Chn chiu dy bo v ct thp l a =5 cm, chiu cao lm vic ca tit din l

ho = h a = 100 5 = 95 cm.

Tnh ton cc thng s:

m =

=

= 0.025 = 0.032

( H s R tra bng ph thuc vo Mc b tng, nhm ct thp v iu kin lm vic, tra bng ta

c R = 0.56) R = 0.41

m < R ta tnh ton nh tit din t ct thp n ( khng cn tnh ton ct thp chu

nn).

T m = 0.025 tra bng ta c = 0.98

Din tch ct thp cn thit l:

3500 7000 3500


69

. .

a

a o

MF

R h

Ct thp nhm CII c Ra = 28000 T/m2

Thay s ta c:

Fa =

= 9 (cm

2)

Chn 425 c Fa = 19.635 cm2 b tr thnh 1 lp. Hm lng ct thp

=

=

x 100% = 0.41 % > 0.05%

Thp cu to chn ging nh thp dc chu lc (425), t vng b tng chu nn.

Ngoi ra, do tit din dm ln hn 500( Theo ti liu BTCT) nn khong gia dm, b tr thm

ct cu to l cc thanh 18.

b) Tnh ton ct ai.

- Kim tra kh nng chu ct ca b tng:

kn.nc.Qmax = 1.2x1x15.3 = 18.36 (T)

Vi kn: h s ph thuc vo cp cng trnh( an ton ta cho tng lc ct ca b tng ln

kim tra, y chon kn = 1.2).

nc: H s ph thuc vo loi t hp ti trng

+/ iu kin cn kim tra:

mb3.Qb = k1.Rk.b.ho.mb3( Theo Ti liu BTCT 1).

Trong :

mb3 = 1.15 : h s iu kin lm vic ca b tng

Rk = 120 T/m2 : cng chu ko ca b tng

k1 = 0.5 + 2. = 0.5 + 2x0.048 = 0.596

Do : mb3.Qb = 0.596x120x0.5x0.95x1.15 = 39.0678 (T)


70

kn.nc.Qmax < mb3.Qb khng cn tnh ton ct ai chu ct. Chn ct ai theo cu

to, chn ct ai 10 a100 ti cc vng cn gi ta (gn tr), ct ai 10 a200 ti cc vng cn

li(

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