BI TP LN CNG TRNH BIN C NHGVHD: THS. TRNH THANH KINMHP: 093110NHM: 01

PHN A : S LIU U VO

I. Kch thc cng trnh: a = 13,5m b = 16,2m c = 27,5m d/ = 0,72/0,014m D/ =1,22/0,020m

II. Tham s sng tnh ton : h = 45,4m H = 3,89m L= = 64,9m

III. Thng s a cht: = 18,8kN/m3 a = 0,95kN/m3 b = 6,8kN/m3 c = 1,1% Thi im tnh ton: t = 10s Tng ti trng ng: P = 35000kN Tng ti trng gi : H = 380kN.

PHN B : TINH TOANI. XAC INH TAI TRONG LN CHN TAI THI IM (t) su khu nc : h = 45,4m Chiu cao sng : H = 3,89m Chiu di sng. : L = 64,9m

1. Phn tch chn : Phn tch khi chn thnh: Cc tr chnh chu tc ng ca sng tr (1), (2), (3) v (4). Hai mt n sng mt trc (A) v mt sau (B), gm cc thanh nm ngang chu tc ng ti trng sng l: (1-2), (3-4). Cc thanh ging cho (1-6), (4-8) Hai mt bn (trng vi hng truyn sng) mt (C), mt (D) gm cc thanh ging cho chu tc ng ca sng l (4-5), (2-7) Gn h trc to Oxyz vo tr (1) c cc hng Ox, Oy, Oz nh hnh v. trong trc Ox trng vi hng truyn sng, Oxy trng vi mt (C). Tr (1) nm trng vi gc to x = 0 s dng cng thc ti trng sng theo Airy tnh : F = FD + Fm Cc tr (4-5), (2-7), (3-8) v (7-8). Cch gc to 1 khong xo khi tnh ton ta thay biu thc (kxt) bng (kx0t). Ta tnh ti trng sng phn b theo cng thc ca Morixn i vi cc tr chnh thng ng.

2. Tnh ton sng theo l thuyt sng Airy: Phng trnh b mt sng c dng:

trong : k l s sng xc nh theo cng thc:

: Tn s gc xc nh theo cng thc:

t = 10s t = 0,97x10 = 9,75o T: chu k. T = 6,45s Thay vo phng trnh (1) ta c phng trnh ng mt sng:

Thnh phn ngang v thnh phn ng ca qu o phn t nc:

(m/s)

(m/s) Gia tc chuyn ng thnh phn ht nc:

(m/s2)

(m/s2)

3. Xc nh ti trng ln cc tr chnh: (1), (2), (3) v (4) Tnh ton theo cng thc MORIXN:

f = f(y) = 0,5CDD|Vx|Vx + Cm Chn h trc ta v cc OXYZ nh hnh v. p dng cng thc MORISN xc nh ti trng phn b ln tr thng ng theo cng thc:

f = f(y) = 0,5CDD|Vx|Vx + Cm trong : : l mt nc bin: =10,25(kN/m3). CD,Cm: h s sc chng tc v sc chng qun tnh (CD =0,61,0); (Cm=1,52). Theo API: Ta chn b mt tr nhn trn : Cd = 0,65; Cm = 1,6. Vx,ax: tc v gia tc theo phng x ca phn t nc (l hm ca y). D: ng knh tr chnh. D = 1,22(m). Tnh ton

Bng 1: Cc thng s u vo ca sng theo cng thc Morixnk0,097m-1

H3,98m

0,97s-1

D1,22m

Cd0,65

Cm1,6

10,25kN/m3

h45,4m

g9,81m/s2

L64,9m

T6,45s

t10s

Bng 2: Ti trng tc dng ln tr chnhTRUxh + yVxaxf

1; 20-1,871843,530-0,045-0,043-0,841

-1,871816,2-0,112-0,109-2,142

-1,871821,77-0,187-0,182-3,634

-1,871843,53-1,522-1,482-37,828

TRUxh+yVxaxf

1;413,5-0,994244,410-0,024-0,023-0,445

-0,994216,2-0,060-0,058-1,125

-0,994222,21-0,104-0,101-1,977

-0,994244,41-0,881-0,857-19,585

4. Xc nh ti trng ln cc thanh xin v thanh nganga. Xt mt A thanh s (1-6), phng trnh b mt sng :

Nhn xt: Tt c nhng im thuc ng thng 7 u c x = 0

Chiu di ngp sng ca thanh 7 l:

vi: Ta im u v im cui thanh s (1-6) l: im u (0 ; 16,2 ; 0) im cui (0 ; 43,53 ; -13,05).

b. Xt mt phng B thanh s (4-5).

Tng t trn ta c phng trnh b mt sng :

Thanh s (4-5) c im u (13,5 ; 16,2 ; 0). im cui (0 ; 43,7; 0). Phng trnh ng thng thanh (4-5) trong mt phng XY

Khi phng trnh b mt sng v ng thng giao nhau th tung thnh phn ht nc bng tung ca giao im thuc trc thanh.

Ta c:

Bng cch gii lp h phng trnh ny ta c X = 0,1m. Kim tra li : VT = 43,52 v VP = 43,50 (chp nhn c). To im ngp sng l: im ngp (0,1; 43,50; 0). im u (13,5; 16,2; 0). chiu di ngp sng ca thanh s (9) l:

c. Thanh xin s (3-8). C to im u v cui l: Nhn xt : tt c cc im thuc thanh (8) u c to X = 13,5

Chiu di ngp sng ca thanh s (8) l:

Thanh s (3-8) c ta im u v im cui l : im u (13,5 ; 16,2 ; -13,5). im cui l (13,5 ; 43,7 ; 0).

d. Xt thanh s (2-7) im u (0 ; 16,2 ; -13,5). im cui (13,5 ; 43,7 ; -13,5) phng trnh ng thng thanh (10) trong mt phng song song vi mp XY l:

Tng t ta c giao im ca thanh (2-7) v phng trnh b mt sng l nghim ca h phng trnh:

Bng cch gii lp h phng trnh ny ta c X = 0,1m Thay vo phng trnh ta c VT = To im ngp sng l : im u (0; 16,2 ; -13,5). im ngp (13,4 ; 43,496 ; -13,5 ) Chiu di ngp sng ca thanh s (2-7)

e. Ti trng tc dng ln cc thanh xin tnh theo trnh t sau B1: xc nh to cc thanh vcc tham s sng Cx,Cy,Cz:

Bng 3: Cc h s vector ch phng cc thanhMATTHANHX2X1Y2Y1Z2Z1LCxCyCz

A1-20016,216,2-13,05013,500,0000,000-0,967

1-60043,5316,2-13,05030,430,0000,898-0,429

C4-50,113,543,516,20030,41-0,1050,8980,000

B3-413,513,516,216,2-13,5013,500,0000,000-1,000

3-813,513,543,716,20-13,526,150,0001,0520,516

D2-713,4043,49616,2-13,5-13,526,160,1051,0430,000

B2:Xc nh thnh phn vn tc ht nc

Bng 4: Tr s thnh phn vn tc ht nc:THANHIEMXYVxVyCxCyCzVnxVnyVnzVn

A1-2AU016,2-0,112-0,1030,0000,000-0,967-0,112-0,1030,0000,152

GIA016,2-0,112-0,1030,0000,000-0,967-0,112-0,1030,0000,152

CUOI016,2-0,112-0,1030,0000,000-0,967-0,112-0,1030,0000,152

1-6AU016,2-0,112-0,1030,0000,898-0,429-0,112-0,020-0,0400,121

GIA029,77-0,402-0,3990,0000,898-0,429-0,402-0,077-0,1540,439

CUOI043,53-1,522-1,5220,0000,898-0,429-1,522-0,294-0,5861,663

C4-5AU016,2-0,112-0,103-0,1050,8980,000-0,120-0,0300,0000,129

GIA6,4529,85-0,395-0,393-0,1050,8980,000-0,428-0,1130,0000,462

CUOI12,943,5-0,884-0,883-0,1050,8980,000-0,957-0,2540,0001,035

B3-4AU12,916,2-0,065-0,0600,0000,000-1,000-0,065-0,0600,0000,089

GIA12,916,2-0,065-0,0600,0000,000-1,000-0,065-0,0600,0000,089

CUOI12,916,2-0,065-0,0600,0000,000-1,000-0,065-0,0600,0000,089

3-8AU12,916,2-0,065-0,0600,0000,000-1,000-0,065-0,0600,0000,089

GIA12,929,95-0,238-0,2370,0000,000-1,000-0,238-0,2370,0000,336

CUOI12,943,7-0,901-0,9010,0000,000-1,000-0,901-0,9010,0001,274

D2-7AU016,2-0,112-0,1030,1051,0430,000-0,1000,0210,0000,095

GIA6,4529,848-0,395-0,3930,1051,0430,000-0,3480,0780,0000,327

CUOI12,943,496-0,883-0,8830,1051,0430,000-0,7770,1750,0000,729

B3:Xc nh cc gia tc thnh phn :

;

Vi gia tc chuyn ng thnh phn ht nc trong trng sng:

THANHIEMXYaxayCxCyCzanxanyanz

A1 2AU016,2-0,109-0,1000,0000,000-0,967-0,109-0,1000,000

GIA016,2-0,109-0,1000,0000,000-0,967-0,109-0,1000,000

CUOI016,2-0,109-0,1000,0000,000-0,967-0,109-0,1000,000

1 6AU016,2-0,109-0,1000,0000,898-0,429-0,109-0,019-0,039

GIA029,77-0,391-0,3890,0000,898-0,429-0,391-0,075-0,150

CUOI043,53-1,482-1,4820,0000,898-0,429-1,482-0,286-0,571

C4 5AU016,2-0,109-0,100-0,1050,8980,000-0,117-0,0300,000

GIA6,4529,85-0,385-0,382-0,1050,8980,000-0,417-0,1100,000

CUOI12,943,5-0,860-0,860-0,1050,8980,000-0,932-0,2480,000

B3 4AU12,916,2-0,064-0,0580,0000,000-1,000-0,064-0,0580,000

GIA12,916,2-0,064-0,0580,0000,000-1,000-0,064-0,0580,000

CUOI12,916,2-0,064-0,0580,0000,000-1,000-0,064-0,0580,000

3 8AU12,916,2-0,064-0,0580,0000,000-1,000-0,064-0,0580,000

GIA12,929,95-0,232-0,2300,0000,000-1,000-0,232-0,2300,000

CUOI12,943,7-0,877-0,8770,0000,000-1,000-0,877-0,8770,000

D2 7AU016,2-0,109-0,1000,1051,0430,000-0,0970,0210,000

GIA6,4529,848-0,385-0,3820,1051,0430,000-0,3390,0760,000

CUOI12,943,496-0,860-0,8600,1051,0430,000-0,7570,1700,000

B4:Tnh ti trng trn 1 m di theo cng thc MORIXN:

B5: Tnh ti trng sng trn 1 n v di thanh:

Bng 6: Tr s ti trng trn 1 n v chiu di thanh:THANHIEMVnvnxvnyvnzanxanyanzfxfyfzf

A1 2AU0,152-0,112-0,1030,000-0,109-0,1000,000-2,160-1,9820,0002,932

GIA0,152-0,112-0,1030,000-0,109-0,1000,000-2,160-1,9820,0002,932

CUOI0,152-0,112-0,1030,000-0,109-0,1000,000-2,160-1,9820,0002,932

1 6AU0,121-0,112-0,020-0,040-0,109-0,019-0,039-2,146-0,381-0,7582,308

GIA0,439-0,402-0,077-0,154-0,391-0,075-0,150-8,216-1,579-3,1458,938

CUOI1,663-1,522-0,294-0,586-1,482-0,286-0,571-38,697-7,480-14,89842,135

C4 5AU0,129-0,120-0,0300,000-0,117-0,0300,000-2,312-0,5850,0002,385

GIA0,462-0,428-0,1130,000-0,417-0,1100,000-8,788-2,3290,0009,092

CUOI1,035-0,957-0,2540,000-0,932-0,2480,000-21,884-5,8190,00022,645

B3 4AU0,089-0,065-0,0600,000-0,064-0,0580,000-1,241-1,1380,0001,684

GIA0,089-0,065-0,0600,000-0,064-0,0580,000-1,241-1,1380,0001,684

CUOI0,089-0,065-0,0600,000-0,064-0,0580,000-1,241-1,1380,0001,684

3 8AU0,089-0,065-0,0600,000-0,064-0,0580,000-1,241-1,1380,0001,684

GIA0,336-0,238-0,2370,000-0,232-0,2300,000-4,768-4,7390,0006,722

CUOI1,274-0,901-0,9010,000-0,877-0,8770,000-21,479-21,4700,00030,370

D2 7AU0,095-0,1000,0210,000-0,0970,0210,000-1,8970,4070,0001,940

GIA0,327-0,3480,0780,000-0,3390,0760,000-6,9561,5600,0007,128

CUOI0,729-0,7770,1750,000-0,7570,1700,000-16,8093,7810,00017,229

II. GII KHUNG PHNG1. a ti trng v cc nt u thanh Cac thanh ngoai h phng ang tinh se a vao tinh toan co th xet bng cach a cac hp lc do tai trong t ln cac thanh o va biu din n gian cac nt u thanh. a. Thanh xin (1-6)ablf1f2f3

15,310,2030,822,9322,9322,932

P111,73FA45,18

P235,18MA7,53

P393,82FB44,60

P4234,56MB7,47

b. Thanh xin (3-8)ablf1f2f3

14,5614,5643,71,6846,72230,37

P145,50FA174,78

P279,12MA37,38

P3153,11FB156,44

P4314,55MB17,53

c. Thanh xin (4-5)ablf1f2f3

15,21,5131,912,3859,09222,645

P143,21FA112,19

P289,12MA23,26

P3190,48FB216,24

P4412,27MB371,07

d. Thanh ngang (1-2) Ti trng tc dng ln thanh (1-2) c a v im (1) nh sau: Lc tp trung: 2,93213,50,5 = 19,79 kN.m Moment tp trung:2,93213,520,5 = 267,18 kN.m

e. Thanh ngang (3-4) Ti trng tc dng ln thanh (3-4) c a v im (4) nh sau: Lc tp trung: 1,68413,50,5 = 12,42 kN.m Moment tp trung: 1,68413,520,5 = 167,67 kN.m

2. Gii khung vi cc ti trng xc nh: Vi gi thit tng ti trng ng v tng ti trng chia u ln cc tr chnh Hng gi theo trc X. Ti trng ng: V = 35000(kN) ti trng t ln tng nh tr l: V1 = 350000,25 = 8750kN Ti trng gi: H= 380(KN) . ti trng t ln tng nh tr l: H1 = 38000,25 = 95kN T hp ti trng : Bao = Ti ng + Ti ngang + Ti sng Cc thanh ngoi h phng ang tnh s a vo tnh ton c th xt bng cch a cc hp lc do ti trng t ln cc thanh v biu din n gin cc lin kt u thanh. Chn mt khung phng nm trong mt phng C tin hnh gii bng phn mm Sap 2000.

(M)(Q)(N)III. TNH TON S B KCH THC CC1. Tnh ton s b kch thc cc: Chn s b kch thc cc theo tiu chun TCVN9246:2012. Chn s b cc c ng knh D = 1,0 (m), b dy = 0,019 (m). Chn chiu di cc cm trong t L = 100m, Chiu di t do ca cc Lo = 2(b + c) = 87,4ma. Sc chu ti dc trc ca cc theo API: Sc chu ti cc hn xc nh theo cng thc: Qd = Qf + Qp = fAs + qAp trong : Qf : Sc khng ma st (kN). Qp : Sc khng mi (kN) F : Sc khng ma st n v (kN). As : Din tch b mt cc (m2). Q : Sc khng mi n v (kPa). Ap : Din tch ton b mi cc (m2). Theo bi: a cht gm 1 lp t c sc khng ct khng thot nc c = ay + b (kN/m2). Vi cc thng s a cht: = 18,8(kN/m3). a = 0,95(N/m3),b = 6,8(kN/m3), c = 1,1%.

2. Trnh t tnh ton kim tra sc chu ti cc.a. Xc nh sc khng ma st: Qf = fAs Do t nn ch c 1 lp t v l loi t dnh nn tnh ton nh sau: Sc khng ma st n v f c xc nh thng qua sc khng ct khng thot nc c v h s f = c trong : c: Sc khng ct khng thot nc ca t ti im ang xt . : H s khng th nguyn, c tnh theo phng trnh: Xc nh h s da vo t s = c/po vi po p lc thng ng hu hiu ti im ang xt. = 0.5 - 0.5 vi 1 = 0.5 - 0.25 vi >1. Vi >1 th chn = 1 tnh ton. tng dn theo su v ti su ymax th = 1. Ta lp mt bi ton nh xc nh ymax m ti :

y max = 5,73m Ta lp bi ton xc nh y m ti

y = 0,89 m Chia t nn thnh 3 lp theo chiu di cc tnh ton, tnh t mt t Lp 1: su (0 0,89)m, chiu dy l1 = 0,89 m Tnh gia lp phn t y = 0,445m

= 0,51,9-0.25 = 0,426 f1= c = 0,426(0,950,445 + 6,8) = 3,08 (KN/m2)

Lp 2: su (0,89 5,73)m, chiu dy l2 = 4,84 m Tnh gia lp phn t y = 2,42 + 0,89 = 3,31m.

= 0,50,35-0.5 = 0,84 f2 = c = 0,84(0,953,31 + 5,73) = 8,39 (kN/m2)

Lp 3: su (5,73 100)m, chiu dy l3 = 94,27m Tnh gia lp phn t y = 47,135 + 5,73 = 52,865m.

= 0,50,126-0.5 = 1,41 > 1.0 ly = 1,0f3 = c = 1,0(0,9552,865 + 6,8) = 57,02(kN/m2) Sc khng ma st mt bn ngoi ng: Qf = fAs = (f1l1 + f2l2 + f3l3)D = (3,080,89 + 8,394,84 + 57,0294,27)1,0 = 17014,48(kN) Sc khng ma st bn trong ng (phn li t bn trong): Qf (li) = fAs = (f1l1 + f2l2 + f3l3)d = (3,080,89 + 8,394,84 + 57,0294,27)0,962 = 16376,23(kN)

b. Xc nh sc khng mi ln din tch thc ca mi cc: Qp = qAp trong : q: Sc khng mi on v q = 9c c = 0,95100 + 6,8 = 101,8 (kN/m2) Ap: Din tch mi cc tnh cho vnh khn,

Ap = cm2)Qp = qAp = 9101,80,0615 = 56,35(kN)

c. Xc nh sc khng mi ln phn li t: Qp (li) = qAp trong : q: Sc khng mi own v q = 9c c = 0,95100 + 6,8 = 101,8(kN/m2) Ap: Din tch mi cc tnh cho li t bn trong cc ,

Ap = Qp (li) = qAp = 9101,80,724 = 663,33 (kN) Nhn xt: ta thy sc khng mi tc dng ln phn li t nh hn sc khng mt trng cc ng, Qp (li) = 663,33(kN) < Qf (li) = 16376,23(kN). V vy sc chu ti cc hn ca cc tnh nh sau: Qd = Qf + Qp + Qp (li) = 17014,48+ 56,35 + 663,33 = 17734,16(kN). Vi FS = 2,0 trong iu kin mi trng khai thc. Sc chu ti cho php ca cc:

Ncc = 9873,13 Vy chiu di cc chn khng tha mn iu kin, ta tin hnh chn li thng s cc: Tnh ton s b kch thc cc: Chn s b kch thc cc theo tiu chun TCVN9246:2012. Chn s b cc c ng knh D = 1,2 (m), b dy = 0,019 (m). Chn chiu di cc cm trong t L = 100m, Chiu di t do ca cc Lo = 2(b + c) = 87,4ma. Sc chu ti dc trc ca cc theo API: Sc chu ti cc hn xc nh theo cng thc: Qd = Qf + Qp = fAs + qAp trong : Qf : Sc khng ma st (kN). Qp : Sc khng mi (kN) F : Sc khng ma st n v (kN). As : Din tch b mt cc (m2). Q : Sc khng mi n v (kPa). Ap : Din tch ton b mi cc (m2). Theo bi: a cht gm 1 lp t c sc khng ct khng thot nc c = ay + b (kN/m2).

b. Xc nh sc khng ma st: Qf = fAs Do t nn ch c 1 lp t v l loi t dnh nn tnh ton nh sau: Sc khng ma st n v f c xc nh thng qua sc khng ct khng thot nc c v h s f = c trong : c: Sc khng ct khng thot nc ca t ti im ang xt . : H s khng th nguyn, c tnh theo phng trnh: Xc nh h s da vo t s = c/po vi po p lc thng ng hu hiu ti im ang xt. = 0.5 - 0.5 vi 1 = 0.5 - 0.25 vi >1. Vi >1 th chn = 1 tnh ton. tng dn theo su v ti su ymax th = 1. Ta lp mt bi ton nh xc nh ymax m ti :

y max = 5,73m Ta lp bi ton xc nh y m ti

y = 0,89 m Chia t nn thnh 3 lp theo chiu di cc tnh ton, tnh t mt t Lp 1: su (0 0,89)m, chiu dy l1 = 0,89 m Tnh gia lp phn t y = 0,445m

= 0,51,9-0.25 = 0,426 f1= c = 0,426(0,950,445 + 6,8) = 3,08 (KN/m2)

Lp 2: su (0,89 5,73)m, chiu dy l2 = 4,84 m Tnh gia lp phn t y = 2,42 + 0,89 = 3,31m

= 0,50,35-0.5 = 0,84 f2 = c = 0,84(0,953,31 + 5,73) = 8,39 (kN/m2)

Lp 3: su (5,73 100)m, chiu dy l3 = 94,27m Tnh gia lp phn t y = 47,135 + 5,73 = 52,865m.

= 0,50,126-0.5 = 1,41 > 1.0 ly = 1,0f3 = c = 1,0(0,9552,865 + 6,8) = 57,02(kN/m2) Sc khng ma st mt bn ngoi ng: Qf = fAs = (f1l1 + f2l2 + f3l3)D = (3,080,89 + 8,394,84 + 57,0294,27)1,2 = 20427,73(kN) Sc khng ma st bn trong ng (phn li t bn trong): Qf (li) = fAs = (f1l1 + f2l2 + f3l3)d = (3,080,89 + 8,394,84 + 57,0294,27)(1,2 0,0192) = 19780,85(kN)

c. Xc nh sc khng mi ln din tch thc ca mi cc: Qp = qAp trong : q: Sc khng mi on v q = 9c c = 0,95100 + 6,8 = 101,8 (kN/m2) Ap: Din tch mi cc tnh cho vnh khn, vi D = 1,2m v d = (1,2 0,0192) = 1,162m

Ap = cm2)Qp = qAp = 9101,80,07 = 64,13(kN)

d. Xc nh sc khng mi ln phn li t: Qp (li) = qAp trong : q: Sc khng mi own v q = 9c c = 0,95100 + 6,8 = 101,8(kN/m2) Ap: Din tch mi cc tnh cho li t bn trong cc ,

Ap = Qp (li) = qAp = 9101,81,106 = 971,17(kN) Nhn xt: ta thy sc khng mi tc dng ln phn li t nh hn sc khng mt trng cc ng, Qp (li) = 971,17(kN) < Qf (li) = 16376,23(kN). V vy sc chu ti cc hn ca cc tnh nh sau: Qd = Qf + Qp + Qp (li) = 20427,73 + 64,13 + 971,17 = 21463,03(kN). Vi FS = 2,0 trong iu kin mi trng khai thc. Sc chu ti cho php ca cc:

Ncc = 9873,13(kN). Tha mn iu kin chn cc s b

3. Sc chu ti ngang ca cc: S liu: D =1,2(m) = 0,019(m); Lo = 87,4(m)Lc = 100(m) ; E = 2,1108(kN/m2) i vi t st:

t st: N = 3,5 ; k = 22Mpa

Ta c:

I = 0,05(D4 d4) = 0,05(1,24 1,1624) = 0,0125(m4)

Tnh cc gi tr

Xut t kt qu SAP gii phn trn Lc ct ti chn : Po = 141,82 kN Moment ti chn : Mo = 1264,17 kN.mLd2 0,665Ld3 + 141,82Ld + 1264,17

Q* = 28,56Ld + 1,995Ld2 141,82

p dng cng thc (4.39): 2(P1 + P2Ld) = 2M* Q* 2(28,56 + 3,99Ld) = 0,3032M* 0,303Q* 57,12 + 7,98Ld = 0,3032(Ld2 0,665Ld3 + 141,82Ld + 1264,17) 0,303(28,56Ld + 1,995Ld2 141,82) = 0 0,061Ld3 + 1,914Ld2 + 3,61Ld 101,91 = 0 Ld = 5.94m > 05,942 0,6655,943 + 141,825,94 + 1264,17= 1463,36(kN.m)Q* = 28,565,94 + 1,9955,942 141,82 = 98,22(kN)

Tm C1, C2 xut pht t iu kin vng v gc xoay ca cc ti tit din z = Ld ca vng do tng ng bng cc gi tr vng v gc xoay ti tit din z = 0 ca vng n hi, tm c :

C1 = -13101,20

C2 = 58496,59

Ly o hm phng trnh (4.32) v cho z= 0 ta c gi tr momen v lc ct ti z = 0. Theo iu kin lin tc th gi tr momen v lc ct ti z = Ld phi tng ng bng gi tr momen v lc ct ti z = 0, t ta c:

4. Phng trnh ng n hi ca cc nh sau: Ta c cc gi tr tnh ton c trn nh sau:C1 = -13101,20C2 = 58496,59C3 = 6204,23C4 = -7969,57P1 = 28,56kNP2 = 3,99kN Mo = 1264,17kNPo = 141,82kN Ld = 5,94m = 0,303 Chuyn v ca cc trong vng do z < Ld (Chiu sau vng do)

Chuyn v ca cc trong vng n hi z Ld (Chiu su vng do)

z = z Ld

= Cc gi tr ni lc theo phng dc trc ca cc nh sau Trong vng do: z < Ld (Chiu su vng do) Momen cc: Lc ct cc: Phn lc nn: p = NDvi t dnh: = c = a + bz = 6,8 + 0,95z Trong vng n hi z Ld (Chiu su vng do) Momen cc: M = 23e-z[C3sin(z) C4cos(z)] Lc ct: Q = -23e-z[-C3sin(z) + C4cos(z) + C3cos(z) + C4cos(z)] Phn lc nn p = kyTrong : k = 22Mpa y: chuyn v ngang cc z = z Ld

IV. TNH TON TNH HC CHN GIN KHOAN: Tnh ton theo cc bc sau y1. Tin hnh bi ton gii cc chu ti ngang ti u cca. Bc 1: Tnh k2 = ko: cng chng chuyn v thng ng s khng thay i trong tnh ton k2= Ko =EAtanh(L) Trong : L = 100m chiu di cc E = 2,1108 I = 0,0125m4 A: din tch u cc A = 0,07m2 : vi k = 7,5Mpa k2 = 0,042,11080,07tanh(0,04100)=587605,63

b. Bc 2: Cho trc (hoc tnh gn ng ln u tin: Ti ngang t ti nh cc ly t kt qu gii ni lc khung phng gin khoanf2x = 141,82kN m2 = 1264,17kN.m

c. Bc 3: Tnh ton cc chu ti ngagn vi f2xi, m2x t ti nh cc, tm chuyn v ngang v gc xoay ti u cc Ta c chuyn v ngang u cc theo phng php Dawson trn ta c: yo = 0,02228m. Tnh gc xoay ti u cc 2 = HoMH + MoMM : Gc xoay ca ccHo = 141,82kN = PoMo = 1264,17kN.m H s nn tnh theo cng thc tnh chuyn v ca ReeseMatlock ci binGio trnh t yu:

Vi A = 2,43148 : l h s khng th nguyn ti v tr u cc, biu th phn lng chuyn v ngang do lc ngang gy ra.

Cc chuyn v n v xc nh theo cng thc: Vi Lc = L = 0,187100 = 18,7 > 4

1,4210-4

1,7710-5

3,5710-6 Gc xoay ti u cc: 2 = HoMH + MoMM = 7,0110-3(radians)

d. Bc 4: Khi c f2xi, m2xi, u2i, 2i Rt k1 t 2 biu thc trn v cho rng bng nhau, chia 2 v cho f2x2, ta c:

Gii h phng trnh trn c nghim

= 5,87m

e. Bc 5: Tnh cc cng ki ng vi chiu di li tm c

Trong : l : chiu di ca cc tng ng. L = 5,87m k1, k3, k4 : nhng cng bin i ph thuc chuyn v ngang, gc xoay ti u 2.

= 457092,76

f. Bc 6 : Tnh ton b kt cu: Thit lp m hnh Sap vi khung chn lm vic ng thi vi nn cc, khung kt cu c im ngm gi nh su l = 5,94m T kt qu Sap ta xut ra kt qu lc ct v moment ti v tr u cc ti mt t

T gi tr Q, M trn lm gi tr u vo gii bi ton cc chu ti ngang theo phng php Reese v Matlock. Tm ra cp chuyn v u cc v t tnh ra l = 8,67m Tin hnh gii bi ton lp t bc 2 n bc 5 cho cc trng hp ng vi li. Ta c bng thng k gii bi ton lp nh sau :u22k1k2k3k4f2xim2xl

0,032850,0095647850,8537982,6831207023,2208129,397,81363,268,70

0,033170,009647468,7537982,6831203801,5207019,797,81363,268,72

Vy chn chiu di tng ng cc l l =8,71m

g. Bc 7: Gii ni lc vi l = 8,71m Vi l trn ta tin hnh gii li ni lc ca kt cu ta c: Tr chnhQ = 100,75kNM = 667,14kN.m Thanh gingQ = 179,16 kNM = 1031,21kN.m

h. Bc 8: Gii cc thc chu ti ngang vi cp ti trng f2xi, m2x tm c sau cng SVTH: V C ANH Trang: ... MSSV: 1051090002 LP: CT10