Chuong 7 Mong Coc Barret

7/29/2019 Chuong 7 Mong Coc Barret

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CHNG 7: MNG CC BARRETTE

CHNG 7 : MNG CC BARRETTE7.1. A CHT7.1.1. Tm tt a cht cng trnh.Cn c vo kt qu kho st ti cc h khoan, a tng v tr xy

dng cng trnh c phn thnh cc lp sau: Lp A:Thnh phn gm ct san lp

Lp 1:Thnh phn gm: bn st, xm xanh en trng thi chy.

Lp 3A:Thnh phn gm: ct pha, xm xanh en trng thi do.Lp ny phn b nh sau:

Lp 3B:Thnh phn gm: ct pha, xm xanh en trng thi do.

Lp ny phn b nh sau:Bng 7.1. Bng tm tt cc gi tr a cht dng trong tnhton.

(kN/m3

)

d(kN/m3)

'(kN/m3)

C(kN/m2)

TTGH1 TTGH2

TTGH1

TTGH2

lp 1 14.9 8 5 6.2 6.4 337' 349'lp

3A18.5 14.1 8.8 7.1 8 1858

'

1917

'lp3B 19.5 15.7 9.8 7.4 8.6

2223'

2235'

7.2. GII THIU V CC BARRETTECc barrette l mt loi cc khoan nhi, thi cng bng loi gu

ngom hnh ch nht. Cc barrette thng thng c tit din hnhch nht, chiu rng t 0,6m n 1,5m v chiu di t 2,2m n6,0m. Ngoi ra c th c cc tit din khc nh ch T, ch thp +,ch I, ch L, ch H,...

Ty theo iu kin a cht cng trnh, ti trng cng trnh m ccbarrette c th c chiu di t vi chc mt n hn mt trm mt.

Cc barrette l mt loi cc khoan nhi nn cng c nhng u,nhc im nh cc khoan nhi.

Ngoi ra cc barrette cn c cc u im nh sau:C th thi cng kt hp nhiu dng hnh hc khc nhau nhm t

tit din chu lc ti u, c moment khng un ln theo phng chu

lc.Sc chu ti ln c v lc dc, lc ct v moment un.

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i vi cc cng trnh c tng hm, phng n mng cc barretrt thun li thit k kt hp vi tng chn tng hm.

Trnh t thit k v tnh ton sc chu ti ca cc barrette v cbn cng nh cc khoan nhi. Cc barrette thit k cho nhng mng

chu ti trng ln. Sc chu ti ca mt cc c th t t 600 tn n3000 tn.

Kch thc cc barrette ca cng ty Bachy Soletanche hay dngnh sau:

Bng 7.2.: Kch thc ph bin ca cc barrete.Cnh di

a(m)2.2 2.2 2.8 2.8 2.8 3.6 3.6 3.6

Cnh

ngnb(m) 0.8 1 0.8 1 1.2 1 1.2 1.5Dintch

S(m2)1.76 2.2 2.24 2.8 3.24 3.6 4.32 5.4

7.3. TNH TON SC CHU TI CA CC7.3.1. Cc thng s ca cc

Cc thng s k thut cc khoan nhi s dng thit k kt cumng:

Kch thc cc:Chiu di : 2.2 mChiu rng: 0.8 m

Din tch tit din cc:

Ap=22.2 0.8 1.76m =

Chn 20a200, A s = 0.00879 m

2

Vt liu s dngB tng s dng chn b tng c cp bn chu nn B25.Cng chu nn tnh ton ca b tng: Rb = 14.5 MPa.Cng chu ko tnh ton ca b tng: Rbt = 1.05 MPa.Cng chu nn tc thi trung bnh ca b tng: Bm=32.11

MPaCt thp s dng loi CIICng chu ko tiu chun ca ct thp: Rsn =295 MPaCng chu ko tnh ton ca ct thp: Rs=280MPa

7.3.2. Theo iu kin vt liu

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Sc chu ti dc trc cho php ca cc theo vt liu lm cc:

ARARP sanbuvl +=

Trong :

Ru: cng chu nn tnh ton ca btng lm cc.Ru = min{R/4.5; 6} vi R l cng chu nn tc thitrung bnh ca b tng cc (MPa).Ab: din tch mt ct ngang ca b tng trong cc.Ran: cng chu nn tnh ton ca ct thp lm cc.Ran = min{Rc/1.5; 220}Rc: gii hn chy ca ct thp (MPa).As: din tch mt ct ngang ca ct thp dc trc.

Vi:Ru = min{R/4.5; 60} =min{32.11/4.5; 6} = 6 MPa.Rs = min{Rsn/1.5; 220} =min{295/1.5; 220} = 196.7 MPa

( )vl u b s sP R A R A (6 1.76-0.00879 196.7 0.00879)*1000 12441.5kN= + = + =

7.3.3. Theo iu kin t nn.Sc chu ti ca cc theo t nn (c, ) c xc nh theo ph lc B TCXD 205-1998 : tnh theo TTGH I, gi tr tnh ton ca c, ,

ly cn di. Gi thit s dng a cht h khoan 1 tnh ton.

ppsspsu qAfAQQQ +=+=

Trong :Qs: Sc chu ti cc hn do ma st bn.Qp: Sc chu ti cc hn do mi cc.fs : Ma st bn n v gia cc v t.qp: Cng chu ti ca t mi cc.

As: Din tch mt bn ca cc.Ap: Din tch mi cc.

Sc chu ti cho php ca cc c tnh theo cng thc:

p

p

s

sa

FS

Q

FS

QQ +=

.Trong :

FSs :H s an ton cho thnh phn ma st bn (FSs =

1.5 2.0) FSp :H s an ton cho sc chng di mi cc (FSp =2.0 3.0)

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Thnh phn ma st QsQs = A sfsi

Ma st trn n v din tch mt bn ca cc c xc nh theocng thc:

ahasi tgcf +='

Trong :ca: Lc dnh gia thn cc v t, ly ca = cI (tnh theo

TTGH I).''

vsh k =

: ng sut php tuyn hu hiu ti mt bn cc(kN/m2).

'

v l ng sut hu hiu theo phng thng ng.ks:h s p lc ngang.ks =1 sin aa - Gc ma st trong gia cc v t nn, i vi cc

khoan nhia = -3 o

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0

60

57.5

5552.5

50

47.5

45

42.5

40

37.5

35

32.5

30

27.5

25

22.5

20

17.5

15

12.5

10

7.5

5

2.5

HK2 HK3

-2.40

-22.20

-33.30

-2.60

-18.90

-27.50

Cat san lap

Bun set, xanh xamen, trang thai chay

Cat pha, xam xanhen, trang thai deo

CHUGIAI

Cat pha, xam xanhen, trang thai deo

Hnh 7.1: Mt ct a cht.Gi thit mi cc cao z= - 50m so vi mt t. Ta ly acht h khoan 2 thit k.Gi zi l khong cch t gia on cc trong lp t i n mt

t, hi l chiu di cc th i trong lp ang xt. Ta c bng tnh thnhphn ma st ca cc nh sau:

Bng 7.3. Sc chu ti ma st ca cc

Zi(m)'v(kN/m2) Li(m) tani

ci(kN/m2) Ksi fsi Qi(kN)

16.1 93.37 12.20.0107

6 6.20.9892

47.1936

5526.57

5

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27.75 172.27 11.10.2859

6 7.10.7250

642.818

42851.7

1

41.65 303.38 16.70.3516

4 7.40.6682

878.691

17884.8

5

Tng

11263.

1

Vy sc chu ti cc hn do ma st bn: Q s = Q si = 11253.1(kN).

Thnh phn mi cc QpSc chu ti mi cc tnh theo cng thc:

Qp= Ap

qp

Trong :Ap Din tch tit din ngang mi cc.qp: Cng chu ti ca t di mi cc, i vi mngsu v mng cc th sc chu ti n v din tch c xcnh nh sau:

qp = c N c +

'

v

N q + d N Mi cc cm vo lp t 3B c:Gc ma st trong: I = 22023; dnh cI=7.4 (kN/m2).Tra bng cc gi tr Nc, Nq, N theo gc ma st trong ca Vesic(Bng 1.23 trang 67 sch Nn mng - Chu Ngc n) tac:Nc = 18.05; Nq = 8.66; N = 8.2

ng sut c hiu ti v tr mi cc (z=-50m):

'

v

= 385.21 (kN/m2)Qp = (10.6 18.05 + 385.21 8.66+9.8 1.2 8.2)1.76 =

6106.3(kN)

Sc chu ti cc hn ca cc tnh theo t nn l:Qu = Qs + Qp = 11263.1+6106.3 = 17369.4(kN)Sc chu ti cho php ca cc tnh theo t nn l:

Qa =

11263.1 6106.37666.9

2 3+ =

( kN)

7.3.4. KT LUN

Sc chu ti ca cc theo cng nh hn sc chu ti ca cctheo vt liu. Vy ta chn sc chu ti theo ch tiu cng lsc chu ti ca cc.

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Vy Qa = 7666.9 (kN).

7.4. MT BNG PHN LOI MNGNguyn tc phn loi mng da trn c s lc tc dng vo mng.

Lc tc dng khc nhau th cu to v kch thc cc cu kin camng cng khc nhau. Tuy nhin n gin cho cng thit k,mng c ti tc dng chnh lch nhau khng qu 15% c th phnvo mt loi mng.

y, do yu cu ca lun vn ch thit k hai mng M1 v M2,do em ch xt hai mng cn cc mng cn li em ch v mkhng tnh.

M3M3

M3 M3

M2

35000

12000

11000

12000

30000

10000 10000 10000

M1

A

B

C

D

1 2 3 4

5400

300 90013001300

300

1300

1550

1300

300

650

1300 300

M1

M1

M1

M1M1

M1

M1

5400

Hnh 7.2: Mt bng phn loi mng.

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7.5. TNH TON MNG M17.5.1.Ni lc

Bng t hp ni lc mng M1:

Bng 7.4. Cc trng hp t hp ni lc

N(kN) Hx(kN) Hy(kN) My(kN.m)Mx(kN.

m)-21066.35 -22.41 -79.51 -107.587 -28.767 Nmax

-17747.37 -3.45 -22.91 111.282 49.169 Mxmax-20995.07 -22.41 -79.51 146.858 42.961 Mymax-19307.01 -31.42 -62.01 55.154 18.71 Hxmax-20995.07 -22.41 -79.51 146.858 42.961 Hymax

Ni lc tnh ton: ta tnh vi t hp 1: Nmax, Hxt, Hyt, Mxt , Myt.,sau ta kim tra kh nng chu lc cho 4 cp ni lc cn li.

7.5.2.TNH TON S B S LNG CC7.5.2.1. c lng s ccS lng cc c lng:

21006.351.2 3.3

7666.9

tt

a

Nn

Q= = =

Vy ta chn s cc b tr l n = 4 cc.Trong :Ntt: ti trng thng ngQa: sc chu ti tnh ton ca mt cc.

: h s xt ti nh hng ca mmen, ly t 1.2 1.5 ty theo gi tr mmen. y ly =1.27.5.2.2. B tr cc

Khong cch t tim hng cc ngoi cng n mp i chn l0.3m.

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5400

300 900 1300 1300

300

1300

1550

1300

300

650

1300 300

5400

Hnh 7.3: Kch thc i cc v b tr cc s b.

7.5.3.KIM TRA THIT K S B7.5.3.1. Kim tra ti trng tc dng ln cc trong mng

Ta kim tra ti trng tc dng ln cc vi tng lc dc tnh ton,moment theo hai phng (Mx, My), lc ngang theo hai phng (Hx,Hy).iu kin kim tra: Pmax Q a ,Pmin 0Chiu cao i chn s b l 2m.hd = 2 (m)Trng lng bn thn i: G = 1.1 25 2 5.45.4 = 1603.8

(kN)Di cc lc t chn ct v trng tm y i cc ta c:

N tt = 21006.35 + 1821.6 = 22827.95 (kN)28.676 79.51 2 187.79ttx x y dM M H h= = =

kNm107.587 22.41 2 152.41tty y x dM M H h= + = =

kNmTi trng tc dng ln cc chu nn nhiu nht:

max max

max

2 2

. .tt x yn n

i i

N M y M xP

n y x= + +

Trong :

n l s lng cc trong i.

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max

ny

,

max

nx

l khong cch tnh t trc ca hng cc chu nn nhiunht n trc i qua trng tm i.

xi, yi - Khong cch tnh t trc cc th i n trc i qua trng tm

i.max

2 2

22888 187.79 (2) 152.41 (2)3863.4

6 (2 2 ) (2 2 )P kN

= + + =

Pmax = 3863.4 (kN)< Qa = 7666.9 (kN)max max

min

2 2

. .tt x yn n

i i

N M y M xP

n y x=

min

2 2

22888 187.79 (2) 152.41 (2)3693.3

6 (2 2 ) (2 2 )P kN

= =

>0

Vy cc m bo kh nng chu ti.7.5.3.2. Kim tra n nh nn di y mng khi quy c

Do ti truyn xung chn ct l ti trng tnh ton nn c titrng tiu chun ta ly ti tnh ton chia cho h s 1.15.

Bng 7.5.: Bng gi tr ti trng tiu chun

Gi tr Hx (kN) Hy (kN) N(kN) Mx (kN.m) My (kN.m)

Tnh ton 304.83 53.31 30258.08 -437.581 975.798

Tiu chun 265.0696 46.35652 26311.37 -380.505 848.52

Do lp 1 l t bn st trng thi chy nn ta b qua lp ny khixt kch thc ngang ca khi mng qui c

Gc truyn lc :4

tb=

Vi:tb - Gc ma st trung bnh ca cc lp t dc theo chiu di cc

(tnh vi trng thi gii hn II)

19 17' 11.1 22 35' 16.7

11.1 16.7

i i

tb

i

h

h

+ = =

+

=21o15021 15' 5.3

4 4

tb

= = =

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f tb/4

Hnh 7.4: Mng khi quy c.Din tch mng khi quy c:Fmq = Lmq.BmqBmq = 5.4 + 2 (11.1+16.7) tan(5.3 o) = 10.57 (m)Lmq = 5.4 + 2 (11.1+16.7) tan(5.3 o) = 10.57 (m)Fmq = Lmq B mq =111.82 (m2)Cc ti trng tiu chun tc dng ti y mng khi quy c:+ T y i tr ln : (ly tb = 22 kN/m3)

G1 = Fmq

Df

tb = 111.82 2 (22-10) = 2683.7( kN) + Trng lng t trong mng khi quy c t y i tr xung

(khng k trng lng cc) vi cc

i trng thi gii hn II.G2 =(Fmq - n.AP)tb.h = (111.82-4 1.76) 8.0540 = 33775.1 (kN) + Trng lng cc (c xt y ni v ton b cc cc nm di

mc nc ngm).G3 = n A p l c = 4 1.76 40 (25-10)= 4224 kN

tc

mqN= Ntc+G1 + G2 + G3 = 59001.4 (kN)

, 93.54 19.48 2 132.5tc tc tc

mq y y x d M M H h kNm= + = =

, 69.14 25 2 163.3tc tc tc

mq x x y d M M H h kNm= + = =

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p lc tiu chun ti y mng khi quy c:tc

mqtc

tb

mq

NP

F=

max

tc tc tcmq xmq ymqtc

mq x y

N M MPF W W

= + +

min

tc tc tc

mq xmq ymqtc

mq x y

N M MP

F W W=

Wx, Wy - Moment chng un ca mng khi quy c.2

6

mq mq

y

B LW

=

2

6

mq mq

x

L BW

=

2527.64 ( / )tctb

P kN m=

2

max529.14( / )tcP kN m=

2

min526.14 ( / )tcP kN m=

Kim tra n nh nn di y mng khi quy c theo cc iukin sau:

0

2.1

min

max

P

RP

RP

tctc

tctc

tb

Trong cng tiu chun ca t nn c xc nh theocng thc:

( . . ' . . . )tc mq fR m A B B D c D = + +

Trong :m - h s iu kin lm vic ca nn t (m = 1).

i - Dung trng y ni lp t th i t y mng khi quy ctr xung.

A, B, D - H s ph thuc gc ma st trong ca lp t mi cccm vo (lp t s 3B). Cn c s liu a cht ta c:

CII

=8.6 kN/m2II = 22o35 A = 0.638, B = 3.55, D = 6.14

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Rtc = 0.638 9.4 10.57+ 3.55 385.21 + 8.6 6.14 = 1500.25 (kN/m2)

Ton b cc iu kin n nh nn u tha.Vy nn di y mng khi quy c tha cc iu kin v n

nh.7.5.3.3. Kim tra ln

Dng phng php cng ln tng lp phn t.Chia t nn di y mng khi qui c thnh cc lp c chiudy hi.hi=Bm 0.25 = 10.57 0.25 = 2.6 m Chn hi = 2 (m)p lc bn thn ca t ti y mng khi qui c:

== iibt l385.21 kN/m2

p lc gy ln ti y mng khi qui c:

gl

== bt

tc

tbP

527.64 385.21 = 142.43 (kN/m2)

gloz k =

ko l h s p lc t tra t L/B v z/B ng vi trng hp ti phnb u trn din tch ch nht.

C th tra bng 2.4 trang 113 sch C hc t- Chu Ngc n.

p1 = (

1

bt

+

2

bt

)/2

p2 = p1 + (

1

gl

+

2

gl

)/2T p1 v p2, ta suy ra e1 v e2 t bng th nghim nn c kt ca

lp t 5a nh sau:

Bng 7.6.: Kt qu th nghim nn c kt ca lp t 3BP(kN) e

0 0.648100 0.607200 0.587400 0.565800 0.551

Cng thc tnh ln :

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S= is

=

1 2

11

i

e eh

e

+

Kt qu tnh ln trnh by trong bng sau :

Bng 7.7: Bng tnh ln mng M1Phnt

z Bdy z/B 'bt gl Ko Pi1 Pi2 e1i e2i S(m)

10 0 385.21

142.4 1

2 2 395 525.60.565

50.560

60.0062

6

22 0.19

404.81

118.8

0.8345

4 2 414.6 527.4 0.5644 0.5605 0.00499

34 0.38

424.41

106.7

0.7498

6 2 434.2534.

10.563

80.560

30.0044

8

46 0.57

444.01 92.9

0.6526

8 2 453.8538.

40.563

10.560

10.0038

4

5 80.76

463.61 76.1

0.5348

10 2 473.4541.

20.562

4 0.560.0030

7

610 0.95

483.21 59.3 0.417

0.02263

Tnh ln dng khi bt>5gl

Tng ln l 2.23 cm < 8 cm, vy mng cc tha iu kin chuln .7.5.4.TNH TON V THIT K I CC7.5.4.1. Kim tra iu kin chc thng

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900

2000

45

Hnh7.5: Hnh thp xuyn thng.

Xc nh hnh thp chc thng bng cch m gc 45o t mpngoi chn ct xung mng. Ct t trn mng c tit din : bc h c =900 900mm.

Chiu cao i 2mTheo hnh v trn ta thy cc cc nm trong thp xuyn thng do

khng cn kim tra xuyn thng.7.5.4.2. Tnh ct thp cho i

V cc khng chu nh nn khng cn tnh thp cho lp trn ca

i cc. Thp lp ny t theo cu to 12a200 c hai phng. Ct thp bin ca i cng chn cu to l 12a200i vi thp cnh di ca i ta ch cn tnh ct thp cho mt

phng v i mng c b tr i xng. Xem i cc lm vic nhmt console ngm ti mp ct, chu ti trng l phn lc cc ucc. Moment tng ng ti ngm (xem nh cnh ct): MI = r i.Pi

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1550

325

5400

300 900 1300 1300

300

1300

1550

1300

300

650

1300 300

5400

Hnh 7.6: M hnh tnh moment un trong i cc.Ta c : r1 = 1.55 m

r2 = 0.325 mThin v an ton ly 2 cc ngoi ca hng cc bin c:P1=Pmax=3948.5 kNP1=Pmax(0.650.4)/1.76= 3948.5(0.650.4)/1.76= 583.3kNVy MI = 3948.51.55+2583.30.325 = 6499.32 kNm

6

max

0

6499.32 1010991.57

0.9 0.9 1800 365s

s

MA

h R

= = =

mm2 = 109.91 cm2

Chn 22a180 b tr (A s = 110.18cm2)7.5.5.KIM TRA CC CHU TI TRNG NGANG

Ta s dng cc t hp ni lc c lc x ngang ln nht kimtra cc chu ti trng ngang.

Bng 7.8.: Bng t hp ni lc kim tra kh nng chuti ngang ca cc.

N(kN) Hx(kN) Hy(kN) My(kN.m) Mx (kN.m) T hp

-19307.01 -31.42 -62.01 55.154 18.71 Hxmax

-20995.07 -22.41 -79.51 146.858 42.961 Hymax

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i vi cc barrete, ta phi phn tch theo c hai phng ri mit hp c.Lc ngang tc dng vo mt cc :Theo phng trc x:

Hox =2

xH

=

31.42

2=15.71 kN

Theo phng trc y:

Hoy =2

yH

=

79.51

2= 39.76 kN

i vi moment:Moment My, Mx chuyn ha ton b thnh lc dc nn khng

cn xt.7.5.5.1. Kim tra theo phng x:7.5.5.1.1. Xc nh h s bin dng

c5

bd

b

K.bE .I

=

K : h s t l.Tra bng G.1 c K = 5000 kN/m4 (t xung quanh cc l ct nh)

Eb : mun n hi ban u ca b tng ccI : moment qun tnh tit din ngang ca cc4 4

40.8 2.2 0.29364 64

bhI m

= = =

bc : B rng qui c ca cc.Theo TCXD 205-1998 th vi D 0.8m th b c = b+ 1 = 0.8+1 = 1.8

mTa c bng kt qu :

b bc K Eb I bd(m) (m) (kN/m4) (kN/m2) (m4) (m-1)0.8 1.8 5000 3E+07 0.293 0.2524

7.5.5.1.1. Kim tra chuyn v ngang u cc y iChiu su tnh i h cc trong t:Le = bd.L = 0.252440 = 10.09 mL l chiu su h cc thc t tnh t y i, L=40 m

Chuyn v ngang v gc xoay ca cc cao trnh y i cxc nh theo cng thc:

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n = yo + o l o +

3 2

3 2

o o

b b

H l M l

E I E I

+

= o +

2

2

o o

b b

H l M l

E I E I

+

Trong :lo l chiu cao ly t i cc n mt t ng vi mng cc icao, vi mng i thp l0 = 0.yo, o - chuyn v ngang v gc xoay ca cc cao trnh mt

t.yo = HoHH + MoHM

o = HoMH + MoMMTrong :Ho : Gi tr tnh ton ca lc ct.Mo : M men un ti mt t ng vi mng cc i cao v tiy i ng vi mng cc i thp.HH, MH - chuyn v cao trnh y i, do cc lc n v tti cao trnh ny gy ra, c xc nh nh sau :

Obbd

3HHA

IE

1

=

O

bbd2MH

BIE

1

=

1

MM O

bd b

CE I

=

Trong : Ao, Bo , Co ph thuc vo chiu su tnh i h cctrong t L

e.

Vi Le = 12.8 m, tra bng G2 TCXD 205 1998 ta c:Ao = 2.441 , Bo = 1.621 , Co = 1.751

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Hnh 7.7: S tc ng ca moment v ti ngang ln cc.

HH =

3 7

2.441

0.2524 3 10 0.293 = 1.7 10 -5 m/kN

MH =

HM =

2 7

1.621

0.25 3 10 0.293 =2.89 10 -6 kN-1

MM =

7

1.751

0.2524 3 10 0.293 = 7.89 10 -7 kN-1m-1

yo =HoHH + MoHM = 15.71 1.7 10 -5 = 0.27 10 -3(m).

o=HoMH + MoMM = 15.71 2.89 10 -6

= 4.55 10-5

(rad).Ta c : n = 0.027cm < gh = 1 cm. = 4.5510-5(rad) < gh = 2/1000.

Vy cc tha iu kin chuyn v ngang v gc xoay.7.5.5.1.2. Biu p lc ngang tc dng vo thn cc

p lc z(kN/m2), m men un Mz(kNm), lc ct Qz(kN) trong cctit din cc c tnh theo cng thc sau:

z =

0 0 00 1 1 1 12 3

. ( . . )

. .

e

bd bd bd b bd b

M HKz y A B C D

E I E I

+ +

My=2bd E b I y 0 A 3 - bd E b I 0 B 3 + M0 C 3+bd

H

0

D3Qz=3bd E b I A 4 - 2bd E b I 0 B 4 + bd M 0 C 4 + H0 D 4Trong : Ze l chiu su tnh i, Ze=bd zCc gi tr A1, A3, A4, B1, B3, B4, D1, D3, D4 c tra trong bng G3ca TCXD 205 1998.

Bng 7.9. ng sutz theo phng ngang ca mt bn cc.z ze A1 B1 C1 D1 z

19


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0 0 1 0 0 0 0 0-

0.3962 0.1 1 0.1 0.005 0 -1.989-

0.3962-

0.7924 0.2 1 0.2 0.02 0.001-

3.6967-

0.7924

-1.1885 0.3 1 0.3 0.045 0.004

-5.1285

-1.1885

-1.5847 0.4 1 0.4 0.08 0.011

-6.2966

-1.5847

-1.9809 0.5 1 0.5 0.125 0.021 -7.207

-1.9809

-2.3771 0.6 0.999 0.6 0.18 0.036

-7.8653

-2.3771

-2.7733 0.7 0.999 0.7 0.245 0.057

-8.3141

-2.7733

-3.1695 0.8 0.997 0.799 0.32 0.085 -8.5427 -3.1695-

3.5656 0.9 0.995 0.899 0.405 0.121-

8.5817-

3.5656-

3.9618 1 0.992 0.997 0.499 0.167-

8.4863-

3.9618

-4.358 1.1 0.987 1.095 0.604 0.222-

8.2207 -4.358-

4.7542 1.2 0.979 1.192 0.718 0.288-

7.8079-

4.7542-

5.1504 1.3 0.969 1.287 0.841 0.365-

7.3081-

5.1504-

5.5466 1.4 0.955 1.379 0.974 0.456-

6.7423-

5.5466-

5.9427 1.5 0.937 1.468 1.115 0.56-

6.1215-

5.9427-

6.3389 1.6 0.913 1.553 1.264 0.678-

5.4352-

6.3389-

6.7351 1.7 0.882 1.633 1.421 0.812-

4.7163-

6.7351-

7.13131.8 0.843 1.706 1.584 0.961 -

3.9799

-

7.1313-7.5275 1.9 0.795 1.77 1.752 1.126

-3.2739

-7.5275

-7.9237 2 0.735 1.823 1.924 1.308

-2.5669

-7.9237

-8.3198 2.1 0.662 1.863 2.098 1.506

-1.8698

-8.3198

-8.716 2.2 0.575 1.887 2.272 1.72-

1.2432 -8.716-

9.1122

2.3 0.47 1.892 2.443 1.95

-0.609

-

9.1122-9.5084 2.4 0.347 1.874 2.609 2.195

-0.0895

-9.5084

20


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-9.9046 2.5 0.202 1.83 2.765 2.454

0.42216

-9.9046

-10.301 2.6 0.033 1.755 2.907 2.724

0.91454

-10.301

-

10.697 2.7 -0.162 1.643 3.03 3.003

1.3136

3

-

10.697-11.093 2.8 -0.385 1.49 3.128 3.288

1.63916

-11.093

-11.489 2.9 -0.64 1.29 3.196 3.574

2.00789

-11.489

-11.885 3 -0.928 1.037 3.225 3.858

2.31002

-11.885

-12.282 3.1 -1.251 0.723 3.207 4.133 2.5074

-12.282

-

12.678

3.2 -1.612 0.343 3.132 4.392 2.7620

3

-

12.678-13.074 3.3 -2.011 -0.112 2.991 4.626

2.91758

-13.074

-13.47 3.4 -2.45 -0.648 2.772 4.8263.0873

9 -13.47-

13.866 3.5 -2.928 -1.272 2.463 4.983.2177

2-

13.866-

14.263 3.6 -3.445 -1.991 2.05 5.0753.3567

2-

14.263-

14.659 3.7 -4 -2.813 1.52 5.0973.4594

3-

14.659

-15.055 3.8 -4.59 -3.742 0.857 5.029

3.62858

-15.055

-15.451 3.9 -5.21 -4.784 0.047 4.853

3.73557

-15.451

-15.847 4 -5.854 -5.941 -0.927 4.548

3.88397

-15.847

-16.244 4.1 -6.514 -7.216 -2.08 4.092

3.99126

-16.244

-16.64 4.2 -7.179 -8.607 -3.428 3.461 4.0686 -16.64

Hnh 7.8. ng sutz theo phng ngang ca mt bn cc.Bng 7.10. Moment un tc dng vo thn cc.

z ze A3 B3 C3 D3 M0 0 0 0 1 0 0

-0.3962 0.1 0 0 1 0.1 6.22404-0.7924 0.2 -0.001 0 1 0.2 12.2961-1.1885 0.3 -0.004 -0.001 1 0.3 18.1653

-1.5847 0.4 -0.011 -0.002 1 0.4 23.4267-1.9809 0.5 -0.021 -0.005 0.999 0.5 28.4341

21


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-2.3771 0.6 -0.036 -0.011 0.998 0.6 32.9846-2.7733 0.7 -0.057 -0.02 0.996 0.699 36.8639-3.1695 0.8 -0.085 -0.034 0.992 0.799 40.2464-3.5656 0.9 -0.121 -0.055 0.985 0.897 42.9953

-3.9618 1 -0.167 -0.083 0.975 0.994 44.8688-4.358 1.1 -0.222 -0.122 0.96 1.09 46.4226-4.7542 1.2 -0.287 -0.173 0.938 1.183 47.4811-5.1504 1.3 -0.365 -0.238 0.907 1.273 47.7902-5.5466 1.4 -0.455 -0.319 0.866 1.358 47.5793-5.9427 1.5 -0.559 -0.42 0.811 1.437 46.8857-6.3389 1.6 -0.676 -0.543 0.739 1.507 45.8766-6.7351 1.7 -0.808 -0.691 0.646 1.566 44.4261-7.1313 1.8 -0.956 -0.867 0.53 1.612 42.5606

-7.5275 1.9 -1.118 -1.074 0.385 1.64 40.5755-7.9237 2 -1.295 -1.314 0.207 1.646 38.2715-8.3198 2.1 -1.487 -1.59 -0.01 1.627 35.7647-8.716 2.2 -1.693 -1.906 -0.271 1.575 33.1127-9.1122 2.3 -1.912 -2.263 -0.582 1.486 30.3192-9.5084 2.4 -2.141 -2.663 -0.949 1.352 27.544-9.9046 2.5 -2.379 -3.109 -1.379 1.165 24.7437-10.301 2.6 -2.621 -3.6 -1.877 0.917 22.0791-10.697 2.7 -2.865 -4.137 -2.452 0.598 19.3326-11.093 2.8 -3.103 -4.718 -3.108 0.197 16.8332-11.489 2.9 -3.331 -5.34 -3.852 -0.295 14.3258-11.885 3 -3.54 -6 -4.688 -0.891 12.0659-12.282 3.1 -3.722 -6.69 -5.621 -1.603 9.71497-12.678 3.2 -3.864 -7.403 -6.653 -2.443 7.79492-13.074 3.3 -3.955 -8.127 -7.785 -3.424 5.95715-13.47 3.4 -3.979 -8.847 -9.016 -4.557 4.4345-13.866 3.5 -3.919 -9.544 -10.34 -5.854 3.14594

-14.263 3.6 -3.757 -10.196 -11.751 -7.325 1.98416-14.659 3.7 -3.471 -10.776 -13.235 -8.979 1.00736-15.055 3.8 -3.036 -11.252 -14.774 -10.821 0.47402-15.451 3.9 -2.427 -11.585 -16.346 -12.854 0.06087-15.847 4 -1.614 -11.731 -17.919 -15.075 0.07326-16.244 4.1 -0.567 -11.638 -19.454 -17.478 0.19612-16.64 4.2 0.747 -11.249 -20.902 -20.048 0.62589

Hnh 7.9: Mmen un Mz dc thn ccBng 7.11. Lc ct Qz (kN) dc thn cc.

22


23/61


z ze A4 B4 C4 D4 Q0 0 0 0 0 1 15.71

-0.3962 0.1 -0.005 0 0 1 15.5183-0.7924 0.2 -0.02 -0.003 0 1 15.0194

-1.1885 0.3 -0.045 -0.009 -0.001 1 14.2135-1.5847 0.4 -0.08 -0.021 -0.003 1 13.1769-1.9809 0.5 -0.125 -0.042 -0.008 0.999 11.9703-2.3771 0.6 -0.18 -0.072 -0.016 0.997 10.5938-2.7733 0.7 -0.245 -0.114 -0.03 0.994 9.12357-3.1695 0.8 -0.32 -0.171 -0.051 0.989 7.62047-3.5656 0.9 -0.404 -0.243 -0.082 0.98 6.09138-3.9618 1 -0.499 -0.333 -0.125 0.967 4.53601-4.358 1.1 -0.603 -0.443 -0.183 0.946 3.01915

-4.7542 1.2 -0.716 -0.575 -0.259 0.917 1.59172-5.1504 1.3 -0.838 -0.73 -0.356 0.876 0.21636-5.5466 1.4 -0.967 -0.91 -0.479 0.821 -1.0107-5.9427 1.5 -1.105 -1.116 -0.63 0.747 -2.2193-6.3389 1.6 -1.248 -1.35 -0.815 0.652 -3.2365-6.7351 1.7 -1.396 -1.613 -1.036 0.529 -4.1469-7.1313 1.8 -1.547 -1.906 -1.299 0.374 -4.911-7.5275 1.9 -1.699 -2.227 -1.608 0.181 -5.5973-7.9237 2 -1.848 -2.578 -1.966 -0.06 -6.1588-8.3198 2.1 -1.992 -2.956 -2.379 -0.35 -6.6107-8.716 2.2 -2.125 -3.36 -2.849 -0.69 -6.7642-9.1122 2.3 -2.243 -3.785 -3.379 -1.1 -6.9073-9.5084 2.4 -2.339 -4.228 -3.973 -1.59 -7.0053-9.9046 2.5 -2.407 -4.683 -4.632 -2.16 -6.9806-10.301 2.6 -2.437 -5.14 -5.355 -2.82 -6.8618-10.697 2.7 -2.42 -5.591 -6.143 -3.58 -6.6643-11.093 2.8 -2.346 -6.023 -6.99 -4.45 -6.493

-11.489 2.9 -2.2 -6.42 -7.892 -5.42 -6.0229-11.885 3 -1.969 -6.765 -8.84 -6.52 -5.6597-12.282 3.1 -1.638 -7.034 -9.822 -7.74 -5.2824-12.678 3.2 -1.187 -7.204 -10.82 -9.08 -4.7096-13.074 3.3 -0.599 -7.243 -11.82 -10.5 -3.4759-13.47 3.4 0.147 -7.118 -12.79 -12.1 -3.1875-13.866 3.5 1.074 -6.789 -13.69 -13.8 -2.7241-14.263 3.6 2.205 -6.212 -14.5 -15.6 -2.3242-14.659 3.7 3.563 -5.338 -15.15 -17.5 -2.3537

-15.055 3.8 5.173 -4.111 -15.6 -19.4 -1.7089-15.451 3.9 7.059 -2.473 -15.78 -21.3 -0.9465

23


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-15.847 4 9.244 -0.358 -15.61 -23.1 0.70572-16.244 4.1 11.749 2.304 -15.01 -24.9 0.69949-16.64 4.2 14.591 5.584 -13.87 -26.5 1.02063

Hnh 7.10. Lc ct Qz (kN) dc thn cc.

7.5.5.1.3. Kim tra n nh nn quanh cciu kin n nh ca nn xung quanh cc khi c p lc ngang do

cc tc ng c dng nh sau:

)(cos

4 '21 IIv

Iz ctg +

Vi Le = 10.09 > 5: Cc di hay cc chu un, n nh nn theo

phng ngang c kim tra ti su :=z

0,85

bd

=

0.853.36

0.2524=

mng sut hu hiu theo phng thng ng ti su z = 3.36 m

tnh t y mng:

v = 1.3 14.5+12.06 5= 79.15 (kN/m 2)i vi cc khoan nhi, h s = 0.61 = 12 l h s k n phn ti trng thng xuyn trong tng ti

trng. Thin v an ton ly 2 = 0.4Vy ta c:

' 0 2

1 2 0

4 4( ) 1 0.4 (79.15 tan 3 37 ' 0.6 6.2) 34.96 /

cos cos3 37 'v I I

I

tg c kN m

+ = + =

Ti su z = 3.36 m , tra trn biu quan h ng sut phpmt bn ca cc theo chiu su, ta c zy = 8.58 kN/m2

Vy iu kin n nh nn quanh cc tha mn.7.5.5.2. Kim tra theo phng y:7.5.5.2.1. Xc nh h s bin dng

c5

bd

b

K.bE .I

=

K : h s t l.Tra bng G.1 c K = 5000 kN/m4 (t xung quanh cc l ct nh)

24


25/61


Eb : mun n hi ban u ca b tng ccI : moment qun tnh tit din ngang ca cc

4 440.8 2.2 0.293

64 64

bhI m

= = =

bc : B rng qui c ca cc.Theo TCXD 205-1998 th vi D 0.8m th b c = b+ 1 = 0.8+1 = 1.8

mTa c bng kt qu :

b bc K Eb I bd(m) (m) (kN/m4) (kN/m2) (m4) (m-1)0.8 1.8 5000 3E+07 0.293 0.2524

7.5.5.2.2. Kim tra chuyn v ngang u cc y iChiu su tnh i h cc trong t:Le = bd.L = 0.2524 40 = 10.09 mL l chiu su h cc thc t tnh t y i, L=40 mChuyn v ngang v gc xoay ca cc cao trnh y i c xc

nh theo cng thc:

n = yo + o l o +

3 2

3 2

o o

b b

H l M l

E I E I

+

= o +

2

2

o o

b b

H l M l

E I E I

+

Trong :lo l chiu cao ly t i cc n mt t ng vi mng cc i

cao, vi mng i thp l0

= 0.yo, o - chuyn v ngang v gc xoay ca cc cao trnh mt t.

yo = HoHH + MoHMo = HoMH + MoMM

Trong :Ho : Gi tr tnh ton ca lc ct.Mo : M men un ti mt t ng vi mng cc i cao v ti y

i ng vi mng cc i thp.HH, MH - chuyn v cao trnh y i, do cc lc n v t ti

cao trnh ny gy ra, c xc nh nh sau :

25


26/61


O

bbd3HH

AIE

1

=

O

bbd

2MHB

IE

1

=

1

MM O

bd b

CE I

=

Trong : Ao, Bo , Co ph thuc vo chiu su tnh i h cc trongt Le.

Vi Le = 12.8 m, tra bng G2 TCXD 205 1998 ta c:Ao = 2.441 , Bo = 1.621 , Co = 1.751

HH =

3 7

2.441

0.2524 3 10 0.293 = 1.7 10 -5 m/kN

MH =

HM =

2 7

1.621

0.25 3 10 0.293 =2.89 10 -6 kN-1

MM =

7

1.751

0.2524 3 10 0.293

= 7.89 10-7

kN-1

m-1

yo =HoHH + MoHM = 39.75 1.7 10 -5 = 0.69 10 -3(m).o=HoMH + MoMM = 39.75 2.89 10 -6 = 0.12 10 -3(rad).Ta c : n = 0.069cm < gh = 1 cm.

= 0.1210-3(rad) < gh = 2/1000.Vy cc tha iu kin chuyn v ngang v gc xoay.

7.5.5.2.3. Biu p lc ngang tc dng vo thn ccp lc z(kN/m2), m men un Mz(kNm), lc ct Qz(kN) trong cc

tit din cc c tnh theo cng thc sau:

z =

0 0 00 1 1 1 12 3

. ( . . ). .

e

bd bd bd b bd b

M HKz y A B C D

E I E I

+ +

My=2bd E b I y 0 A 3 - bd E b I 0 B 3 + M0 C 3+bd

H

0

D3Qz=3bd E b I A 4 - 2bd E b I 0 B 4 + bd M 0 C 4 + H0 D 4Trong : Ze l chiu su tnh i, Ze=bd z

Cc gi tr A1, A3, A4, B1, B3, B4, D1, D3, D4 c tra trong bng G3ca TCXD 205 1998.Bng 7.12. ng sutz theo phng ngang ca mt bn cc

26


27/61


` ze A1 B1 C1 D1 z0 0 1 0 0 0 0 0-

0.3962 0.1 1 0.1 0.005 0-

5.0332-

0.3962-

0.7924 0.2 1 0.2 0.02 0.001-

9.3548-

0.7924-

1.1885 0.3 1 0.3 0.045 0.004-

12.978-

1.1885-

1.5847 0.4 1 0.4 0.08 0.011-

15.934-

1.5847-

1.9809 0.5 1 0.5 0.125 0.021-

18.238-

1.9809-

2.3771 0.6 0.999 0.6 0.18 0.036-

19.903-

2.3771-

2.77330.7 0.999 0.7 0.245 0.057 -

21.039

-

2.7733-3.1695 0.8 0.997 0.799 0.32 0.085

-21.618

-3.1695

-3.5656 0.9 0.995 0.899 0.405 0.121

-21.716

-3.5656

-3.9618 1 0.992 0.997 0.499 0.167

-21.475

-3.9618

-4.358 1.1 0.987 1.095 0.604 0.222 -20.803 -4.358

-

4.7542

1.2 0.979 1.192 0.718 0.288 -

19.758

-

4.7542-5.1504 1.3 0.969 1.287 0.841 0.365

-18.493

-5.1504

-5.5466 1.4 0.955 1.379 0.974 0.456

-17.062

-5.5466

-5.9427 1.5 0.937 1.468 1.115 0.56

-15.491

-5.9427

-6.3389 1.6 0.913 1.553 1.264 0.678

-13.754

-6.3389

-6.7351 1.7 0.882 1.633 1.421 0.812

-11.935

-6.7351

-7.1313 1.8 0.843 1.706 1.584 0.961

-10.071

-7.1313

-7.5275 1.9 0.795 1.77 1.752 1.126

-8.2847

-7.5275

-7.9237 2 0.735 1.823 1.924 1.308

-6.4956

-7.9237

-8.3198 2.1 0.662 1.863 2.098 1.506

-4.7317

-8.3198

-8.716 2.2 0.575 1.887 2.272 1.72 -3.1461 -8.716

-9.1122 2.3 0.47 1.892 2.443 1.95 -1.5411 -9.1122- 2.4 0.347 1.874 2.609 2.195 - -

27


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9.5084 0.2265 9.5084-

9.9046 2.5 0.202 1.83 2.765 2.4541.0683

1-

9.9046-

10.301 2.6 0.033 1.755 2.907 2.724 2.3143-

10.301

-10.697 2.7 -0.162 1.643 3.03 3.003

3.32421

-10.697

-11.093 2.8 -0.385 1.49 3.128 3.288

4.14799

-11.093

-11.489 2.9 -0.64 1.29 3.196 3.574

5.08106

-11.489

-11.885 3 -0.928 1.037 3.225 3.858

5.84564

-11.885

-12.282 3.1 -1.251 0.723 3.207 4.133

6.34511

-12.282

-12.678 3.2 -1.612 0.343 3.132 4.392 6.98946 -12.678-

13.074 3.3 -2.011 -0.112 2.991 4.6267.3830

9-

13.074-13.47 3.4 -2.45 -0.648 2.772 4.826 7.8128 -13.47

-13.866 3.5 -2.928 -1.272 2.463 4.98

8.14262

-13.866

-14.263 3.6 -3.445 -1.991 2.05 5.075

8.49437

-14.263

-

14.659

3.7 -4 -2.813 1.52 5.097 8.7542

7

-

14.659-15.055 3.8 -4.59 -3.742 0.857 5.029

9.18231

-15.055

-15.451 3.9 -5.21 -4.784 0.047 4.853

9.45306

-15.451

-15.847 4 -5.854 -5.941 -0.927 4.548

9.82858

-15.847

-16.244 4.1 -6.514 -7.216 -2.08 4.092

10.1001

-16.244

-16.64 4.2 -7.179 -8.607 -3.428 3.461 10.2958 -16.64

Hnh 7.11. ng sutz theo phng ngang ca mt bn cc.

Bng 7.13. Moment un tc dng vo thn cc

` ze A3 B3 C3 D3 M

28


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0 0 0 0 1 0 0-0.3962 0.1 0 0 1 0.1 15.7503-0.7924 0.2 -0.001 0 1 0.2 31.1161-1.1885 0.3 -0.004 -0.001 1 0.3 45.9682

-1.5847 0.4 -0.011 -0.002 1 0.4 59.2826-1.9809 0.5 -0.021 -0.005 0.999 0.5 71.9541-2.3771 0.6 -0.036 -0.011 0.998 0.6 83.4693-2.7733 0.7 -0.057 -0.02 0.996 0.699 93.2861-3.1695 0.8 -0.085 -0.034 0.992 0.799 101.846-3.5656 0.9 -0.121 -0.055 0.985 0.897 108.802-3.9618 1 -0.167 -0.083 0.975 0.994 113.543-4.358 1.1 -0.222 -0.122 0.96 1.09 117.475-4.7542 1.2 -0.287 -0.173 0.938 1.183 120.153

-5.1504 1.3 -0.365 -0.238 0.907 1.273 120.936-5.5466 1.4 -0.455 -0.319 0.866 1.358 120.402-5.9427 1.5 -0.559 -0.42 0.811 1.437 118.647-6.3389 1.6 -0.676 -0.543 0.739 1.507 116.093-6.7351 1.7 -0.808 -0.691 0.646 1.566 112.423-7.1313 1.8 -0.956 -0.867 0.53 1.612 107.702-7.5275 1.9 -1.118 -1.074 0.385 1.64 102.678-7.9237 2 -1.295 -1.314 0.207 1.646 96.8482-8.3198 2.1 -1.487 -1.59 -0.01 1.627 90.5046-8.716 2.2 -1.693 -1.906 -0.271 1.575 83.7934-9.1122 2.3 -1.912 -2.263 -0.582 1.486 76.7244-9.5084 2.4 -2.141 -2.663 -0.949 1.352 69.7015-9.9046 2.5 -2.379 -3.109 -1.379 1.165 62.6151-10.301 2.6 -2.621 -3.6 -1.877 0.917 55.8723-10.697 2.7 -2.865 -4.137 -2.452 0.598 48.9222-11.093 2.8 -3.103 -4.718 -3.108 0.197 42.5974-11.489 2.9 -3.331 -5.34 -3.852 -0.295 36.2522

-11.885 3 -3.54 -6 -4.688 -0.891 30.5334-12.282 3.1 -3.722 -6.69 -5.621 -1.603 24.5843-12.678 3.2 -3.864 -7.403 -6.653 -2.443 19.7255-13.074 3.3 -3.955 -8.127 -7.785 -3.424 15.0749-13.47 3.4 -3.979 -8.847 -9.016 -4.557 11.2217-13.866 3.5 -3.919 -9.544 -10.34 -5.854 7.96097-14.263 3.6 -3.757 -10.196 -11.751 -7.325 5.02102-14.659 3.7 -3.471 -10.776 -13.235 -8.979 2.54918-15.055 3.8 -3.036 -11.252 -14.774 -10.821 1.19954

-15.451 3.9 -2.427 -11.585 -16.346 -12.854 0.15404-15.847 4 -1.614 -11.731 -17.919 -15.075 0.18538

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-16.244 4.1 -0.567 -11.638 -19.454 -17.478 0.49629-16.64 4.2 0.747 -11.249 -20.902 -20.048 1.58385

Hnh 7.12: Mmen un Mz dc thn ccBng 7.14. Lc ct Qz (kN) dc thn cc

z ze A4 B4 C4 D4 Q0 0 0 0 0 1 39.755

-0.3962 0.1 -0.005 0 0 1 39.2698-0.7924 0.2 -0.02 -0.003 0 1 38.0075-1.1885 0.3 -0.045 -0.009 -0.001 1 35.9681-1.5847 0.4 -0.08 -0.021 -0.003 1 33.3449

-1.9809 0.5 -0.125 -0.042 -0.008 0.999 30.2916-2.3771 0.6 -0.18 -0.072 -0.016 0.997 26.8081-2.7733 0.7 -0.245 -0.114 -0.03 0.994 23.0877-3.1695 0.8 -0.32 -0.171 -0.051 0.989 19.284-3.5656 0.9 -0.404 -0.243 -0.082 0.98 15.4146-3.9618 1 -0.499 -0.333 -0.125 0.967 11.4786-4.358 1.1 -0.603 -0.443 -0.183 0.946 7.64012-4.7542 1.2 -0.716 -0.575 -0.259 0.917 4.02794-5.1504 1.3 -0.838 -0.73 -0.356 0.876 0.54751

-5.5466 1.4 -0.967 -0.91 -0.479 0.821 -2.5577-5.9427 1.5 -1.105 -1.116 -0.63 0.747 -5.6161-6.3389 1.6 -1.248 -1.35 -0.815 0.652 -8.1902-6.7351 1.7 -1.396 -1.613 -1.036 0.529 -10.494-7.1313 1.8 -1.547 -1.906 -1.299 0.374 -12.427-7.5275 1.9 -1.699 -2.227 -1.608 0.181 -14.164-7.9237 2 -1.848 -2.578 -1.966 -0.06 -15.585-8.3198 2.1 -1.992 -2.956 -2.379 -0.35 -16.729

-8.716 2.2 -2.125 -3.36 -2.849 -0.69 -17.117-9.1122 2.3 -2.243 -3.785 -3.379 -1.1 -17.479-9.5084 2.4 -2.339 -4.228 -3.973 -1.59 -17.727-9.9046 2.5 -2.407 -4.683 -4.632 -2.16 -17.665-10.301 2.6 -2.437 -5.14 -5.355 -2.82 -17.364-10.697 2.7 -2.42 -5.591 -6.143 -3.58 -16.864-11.093 2.8 -2.346 -6.023 -6.99 -4.45 -16.431-11.489 2.9 -2.2 -6.42 -7.892 -5.42 -15.241-11.885 3 -1.969 -6.765 -8.84 -6.52 -14.322

-12.282 3.1 -1.638 -7.034 -9.822 -7.74 -13.367-12.678 3.2 -1.187 -7.204 -10.82 -9.08 -11.918-13.074 3.3 -0.599 -7.243 -11.82 -10.5 -8.796

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-13.47 3.4 0.147 -7.118 -12.79 -12.1 -8.0661-13.866 3.5 1.074 -6.789 -13.69 -13.8 -6.8934-14.263 3.6 2.205 -6.212 -14.5 -15.6 -5.8815-14.659 3.7 3.563 -5.338 -15.15 -17.5 -5.9561

-15.055 3.8 5.173 -4.111 -15.6 -19.4 -4.3244-15.451 3.9 7.059 -2.473 -15.78 -21.3 -2.3952-15.847 4 9.244 -0.358 -15.61 -23.1 1.78587-16.244 4.1 11.749 2.304 -15.01 -24.9 1.77009-16.64 4.2 14.591 5.584 -13.87 -26.5 2.58276

Hnh 7.13. Lc ct Qz (kN) dc thn cc

7.5.5.2.4. Kim tra n nh nn quanh cciu kin n nh ca nn xung quanh cc khi c p lc ngang docc tc ng c dng nh sau:

)(cos

4 '21 IIv

I

z ctg

+

Vi Le = 10.09 > 5: Cc di hay cc chu un, n nh nn theo

phng ngang c kim tra ti su :=z

0,85

bd =

0.853.36

0.2524

=

mng sut hu hiu theo phng thng ng ti su z = 3.36 m

tnh t y mng: v = 1.3 14.5+12.06 5= 79.15 (kN/m 2)

i vi cc khoan nhi, h s = 0.61 = 12 l h s k n phn ti trng thng xuyn trong tng ti

trng. Thin v an ton ly 2 = 0.4Vy ta c:

' 0 2

1 2 0

4 4( ) 1 0.4 (79.15 tan 3 37 ' 0.6 6.2) 34.96 /

cos cos3 37 'v I I

I

tg c kN m

+ = + =

Ti su z = 3.36 m , tra trn biu quan h ng sut phpmt bn ca cc theo chiu su, ta c zy = 21.716 kN/m2

Vy iu kin n nh nn quanh cc tha mn.7.5.6. TNH CT THP TRONG CC

7.5.6.1. Tnh theo phng x7.5.6.1.1. Kim tra cc chu un

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Ta c gi tr moment Mmax ca cc khi chu ti trng ngang l (cnc trn th quan h moment theo su):

Mmax = 47.79 (kN.m)Din tch ct thp mt cnh ca tit din tng ng ca cc

khoan nhi:

s

sRh

MA

0

max

9.0=

Chn a = 10cm, ta c din tch ct thp cn thit :

62max

0

47.79 1090.3

0.9 0.9 2100 280s

s

MA mm

h R

= = =

Din tch ct thp ny b tr theo mt cnh di ca cc.S thp chn ban u theo mt cnh ngn ca cc l 2 20 c din tch 628.3 mm2 ( b i cc ct thp gc)

Vy ct thp dc trong cc chu mmen un do ti ngang gyra.7.5.6.1.2. Kim tra cc chu ct

Ta c gi tr Qmax ca cc khi chu ti trng ngang l: Qmax = 15.71kN.

Kim tra iu kin tnh ct ai :0.35Rbbho = 0.35 14500 1.060 0.970 = 5218.12 (kN) > Q. 0.6Rbtbho = 0.6 1050 1.060 0.970 = 647.77 (kN) >Q. Nh vy ct ai b tr cu to. Chn ct ai 10a200.

7.5.6.2. Tnh theo phng y7.5.6.2.1. Kim tra cc chu un


Mmax = 120.94 (kN.m)Din tch ct thp mt cnh ca tit din tng ng ca cc

khoan nhi:

s

sRh

MA

0

max

9.0=


62max

0

120.94 10228.53

0.9 0.9 2100 280s

s

MA mm

h R

= = =

Din tch ct thp ny b tr theo mt cnh di ca cc.

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S thp chn ban u theo mt cnh ngn ca cc l 2 20 c din tch 628.3 mm2 ( b i cc ct thp gc)

Vy ct thp dc trong cc chu mmen un do ti ngang gyra.

Theo l thuyt ta s ct thp chu m men un ca cc ti v trmoment c Mz = 0, tc l su khong 10.5m tnh t y i.7.5.6.2.2. Kim tra cc chu ct


Kim tra iu kin tnh ct ai :0.35Rbbho = 0.35 14500 1.060 0.970 = 5218.12 (kN) > Q. 0.6Rbtbho = 0.6 1050 1.060 0.970 = 647.77 (kN) >Q.

Nh vy ct ai b tr cu to. Chn ct ai 10a200.7.6. TNH TON MNG M27.6.1.Ni lc

Bng t hp ni lc ca mng M3 :Bng 7.15. Cc trng hp t hp ni lc

N(kN) Hx(kN) Hy(kN) My(kN.m)Mx(kN.m

)-183779.07 88.26 15.99 14944.97 -5190.72 Nmax-165036.97 3680.7 1782.65 171244.6 184442 Mxmax-158361.17 356.59 -2043.33 178508.8 5108.844 Mymax-161242.91 3664.53 2063.59 141819.6 161164.2 Hxmax-161337.28 -22.83 2153.11 -124982 -8881.09 Hymax

7.6.2.TNH TON S B S LNG CC7.6.2.1. c lng s cc

S lng cc c lng:183779

1.2 28.77666.9

tt

a

Nn Q= = =

Trong :Ntt: ti trng thng ngQa: sc chu ti tnh ton ca mt cc.

: h s xt ti nh hng ca mmen, ly t 1.2 1.5 ty theo gi tr mmen. y ly =1.27.6.2.2. B tr cc

B tr cc cch nhau 1 khong cch gia 2 mp cc l 1.6 m

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Khong cch t tim hng cc ngoi cng n mp i chn l 0.3m.7.6.3.KIM TRA THIT K S B7.6.3.1. Kim tra ti trng tc dng ln cc trong mng

Ta kim tra ti trng tc dng ln cc vi tng lc dc tnh ton,moment theo hai phng (Mx, My), lc ngang theo hai phng

(Hx, Hy).

iu kin kim tra:

max minP Qa , P 0

Chiu cao i chn s b l:dh

= 2.5 (m)

Din tch i mng ln hn 100m2 nn tnh ton theo mng bcc.

Ni lc cc:

Hnh 7.14. M hnh mng trong SAFE .

Gii ni lc cc v momen i bng phn mm SAFE 12.3.1

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Trc ht phi xut file Save story as SAFE v12.f2k text file t m

hnh etabs m hn cng trnh trc .

Sau import file safe.f2k vo phn mm SAFE v12.3.1.

H s nn K :

V ta ang i tm phn lc cc m cha bit phn lc cc nn ta

ly Qatk tnh ton v m hnh trong SAFE 12 trong ln S

ta chn ln gii hn Sgh=8 cm

= = =

a

gh

Q 7666.9K 958.36(kN / mm)

0.1S 0.1 80

Sau khi gii lp nhiu ln ta c kt qu:

Nu chn 35 cc th ta c cc gi tr nh sau:

maxP 7356.9(kN) Qa 7666.9(kN)= < =

minP 3302.5(kN) 0= >

Vy cc m bo kh nng chu ti.

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Hnh 7.15. Kt qu tnh phn lc u cc trong SAFE vi thp BAO max.

M2

4000 4000

2400

11000

2400

700

2

400

2400

2400

2400

2

400

2400

700

15800

1400 3800 3800 3800 3800 1400

18000

1 1

1

1

10000

Hnh 7.16. Mt bng mng M2 .7.6.3.2. Kim tra n nh nn di y mng khi quy c

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Do ti truyn xung chn ct l ti trng tnh ton nn c titrng tiu chun ta ly ti tnh ton chia cho h s 1.15.

Bng 7.16. Bng gi tr ti trng tiu chun ca

Gi tr Hx (kN) Hy (kN) N(kN) Mx (kN) My (kN)

Tnh ton 88.26 15.99 -183779.07 -5190.72 14944.97Tiu chun 76.7478 13.9043 -159808 -4513.7 12995.6

Do lp 1 l t bn st trng thi chy nn ta b qua lp ny khixt kch thc ngang ca khi mng qui cGc truyn lc :

4

tb =

Vi:tb - Gc ma st trung bnh ca cc lp t dc theo chiu dicc (tnh vi trng thi gii hn II

19 17' 11.1 22 35' 16.721 15'

11.1 16.7

i i

tb

i

h

h

+ = = =

+

021 15' 5.34 4

tb

= = =

f tb/4

37

Lp tyu


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Hnh 7.17: Mng khi quy cDin tch mng khi quy c:Fmq = Lmq.BmqBmq = 15.2 + 2(11.1+16.7)tan(5.3o) = 20.37 (m)

Lmq = 17.4 + 2(11.1+16.7)tan(5.3o) = 22.57 (m)Fmq = LmqBmq =459.95 (m2)Cc ti trng tiu chun tc dng ti y mng khi quy c:+ T y i tr ln : (ly tb = 22 kN/m3)

G1 = Fmq

Df

tb = 459.952.5(22-10) = 13798.4 kN+ Trng lng t trong mng khi quy c t y i tr xung(khng k trng lng cc) vi cc i trng thi gii hn II.G2 =(Fmq - n.AP)tb.h = (459.95-351.76)8.0540 = 128402.8

(kN)+ Trng lng cc (c xt y ni v ton b cc cc nm dimc nc ngm).G3 = nAplc = 351.7640 (25-10)= 36960 kN

tc

mqN= Ntc+G1 + G2 + G3 = 338969.1 (kN)

, 4513.7 76.74 2 4330.8tc tc tc

mq y y x d M M H h kNm= + = =

, 12996.6 13.925 2.5 13030.4tc tc tcmq x x y d M M H h kNm= + = + =

p lc tiu chun ti y mng khi quy c:tc

mqtc

tb

mq

NP

F=

max

tc tc tc

mq xmq ymqtc

mq x y

N M MP

F W W= + +

min

tc tc tc

mq xmq ymqtc

mq x y

N M MP

F W W=

Wx, Wy - Moment chng un ca mng khi quy c.

8.

2

6

mq mq

y

B LW

=

2

6

mq mq

x

L BW

=

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2736.97( / )tctb

P kN m=

2

max747.81( / )tcP kN m=

2

min 726.14( / )

tcP kN m=

Kim tra n nh nn di y mng khi quy c theo cc iukin sau:

0

2.1

min

max

P

RP

RP

tctc

tctc

tb

Trong cng tiu chun ca t nn c xc nh theo

cng thc:( . . ' . . . )tc mq fR m A B B D c D = + +

Trong :m - h s iu kin lm vic ca nn t (m = 1).i - Dung trng y ni lp t th i t y mng khi quy ctr xung.A, B, D - H s ph thuc gc ma st trong ca lp t mi cc

cm vo (lp t s 3B). Cn c s liu a cht ta c:CII=8.6 kN/m2II = 22o35 A = 0.638, B = 3.55, D = 6.14Rtc = 0.63820.379.8 + 3.55385.21 + 8.66.14 = 1325.77(kN/m2)Ton b cc iu kin n nh nn u tha.Vy nn di y mng khi quy c tha cc iu kin v nnh.

7.6.3.3. Kim tra lnDng phng php cng ln tng lp phn t.Chia t nn di y mng khi qui c thnh cc lp c chiudy hihi=Bm 0.25 = 20.37 0.25 = 5.1 m Chn hi = 2 (m)p lc bn thn ca t ti y mng khi qui c:

== iibt l385.21 kN/m2

p lc gy ln ti y mng khi qui c:

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gl

== bt

tc

tbP

736.97 385.21 = 351.76 (kN/m2)

gloz k =

ko l h s p lc t tra t L/B v z/B ng vi trng hp ti phnb u trn din tch ch nht.C th tra bng 2.4 trang 113 sch C hc t- Chu Ngc n.

p1 = (

1

bt

+

2

bt

)/2

p2 = p1 + (

1

gl

+

2

gl

)/2T p1 v p2, ta suy ra e1 v e2 t bng th nghim nn c kt ca

lp t 5a nh sau:Bng 7.17.: Kt qu th nghim nn c kt ca lp t 3B

P(kN) e

0 0.648

100 0.607

200 0.587

400 0.565

800 0.551

Cng thc tnh ln :

S= is

=

1 2

11

i

e eh

e

+

Tnh ln dng khi bt>5gl

Bng 7.18.: Kt qu tnh ln mng M2.Phn t z

Bdy

z/Bm 'bt gl Ko Pi1 Pi2 e1i e2i s

10 0 385.21

351.766 1

2 2 395.01742.9

060.5655

0.554

0.015

2

2 0.1 404.81344.0

27 0.978

4 2 414.61741.5

760.5644

0.554

0.013

3 4 0.2 424.4 309.9 0.881

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1 06

6 2 434.21727.0

550.5638

0.555

0.012

4

6 0.29444.0

1275.7

84 0.784

8 2 453.81 712.534 0.5631 0.556 0.009

58 0.39

463.61

241.663 0.687

10 2

473.41

697.837

0.5624

0.556

0.009

6

10

0.49

483.21

207.19 0.589

12 2

493.01

690.868

0.5617

0.556

0.007

712 0.59 502.81 188.527 0.54814 2

512.61

686.054

0.5611

0.556

0.006

8

14

0.69

522.41

158.362 0.511

16 2

532.21

676.752

0.5603

0.557

0.005

9

16

0.79

542.01

130.722 0.474

1

8 2

551.8

1

669.9

74

0.55

96

0.55

8

0.00

3

10

18

0.88

561.61

105.607 0.437

0.079

Tng ln l 7.9 cm < 8 cm, vy mng cc tha iu kin chuln .7.6.4. TNH TON V THIT K I CC7.6.4.1. Kim tra iu kin chc thng

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M2

4000 4000

2400

11000

2400

700

2400

240

0

2400

2400

2400

2400

70

0

15800

1400 3800 3800 3800 3800 1400

18000

1 1

1

1

10000

Hnh 7.18: Hnh y thp xuyn thng

Xc nh hnh thp chc thng bng cch m gc 45o t mpngoi chn ct xung mng. Chiu cao i 2.5m

Chn a = 20 cm chiu cao lm vic ca i h o = 250 -20 = 230

cm( ) 183779.1 21 3302.5 114426.6( )

tt

xt i xtP N P kN= = =

Trong :

Ntt

lc dc tnh ton ti chn ct (ly t hp Ntt

max)

Pi(xt) phn lc u cc nm trong phm vi y ln thp

xuyn thng. y thin v an ton sinh vin ly P i = Pmin.

00. .2( 2 ). . 1 1200 2 (11.8 10.8 2 0.6) 2.3 2.3 / 0.6 503608( )cx bt c c

hP R h b c h kN

c= + + = + + =

Trong :

l h s ly theo loi b tng (b tng nng ly = 1)Rbt cng chu ko ca b tng.

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h0 chiu cao lm vic ca tit din ( ly t mt trn ca

i n trng tm lp di ct thp ca i).

c khong cch t mp ct ti mp cc nm ngoi thpxuyn thng

bc, hc chiu cao v chiu rng ca tit din ct.

Suy ra : Pxt < Pcx . Vy i tha iu kin xuyn thng.7.6.4.2. Tnh ct thp cho iVic tnh ton ct thp cho i mng c da trn kt qu tnh nilc trong phn mm SAFE.Kt qu ni lc trong cc di nh sau:

Hnh 7.19:Moment un trong i cc theo phng y vit hp BAO min.

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Hnh 7.20:Moment un trong i cc theo phng y vit hp BAO max.

Hnh 7.21:Moment un trong i cc theo phng x vit hp BAO min.

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Hnh 7.22:Moment un trong i cc theo phng x vi

t hp BAO max.Vt liu:

B30: Rb= 17 MPa10mm Q. 0.6Rbtbho = 0.6 1050 1.060 0.970 = 647.77 (kN) >Q. Nh vy ct ai b tr cu to. Chn ct ai 10a200.

7.6.6.2. Tnh theo phng y7.6.6.2.1. Kim tra cc chu un


Mmax = 120.94 (kN.m)

Din tch ct thp mt cnh ca tit din tng ng ca cckhoan nhi:

s

sRh

MA

0

max

9.0=


62max

0

120.94 10228.53

0.9 0.9 2100 280s

s

MA mm

h R

= = =

Din tch ct thp ny b tr theo mt cnh di ca cc.S thp chn ban u theo mt cnh ngn ca cc l 2 20 c

din tch 628.3 mm2 ( b i cc ct thp gc)Vy ct thp dc trong cc chu mmen un do ti ngang gy

ra.Theo l thuyt ta s ct thp chu m men un ca cc ti v tr

moment c Mz = 0, tc l su khong 10.5m tnh t y i.7.6.6.2.2. Kim tra cc chu ct


Kim tra iu kin tnh ct ai :0.35Rbbho = 0.35 14500 1.060 0.970 = 5218.12 (kN) > Q. 0.6Rbtbho = 0.6 1050 1.060 0.970 = 647.77 (kN) >Q.

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Chuong 7 Mong Coc Barret