7-Tinh Mong Coc Nhoi

GVHD KC :C BCH V HONG LAN N TT NGHIP KSXD KHA 2007-2012

GVHDTC: THY L VN THNG CHUNG C NG THUN

CHNG 7 : TNH MNG--------------1.IU KIN A CHT CNG TRNH Mt ct a cht cng trnh :-0.300

700

1

1

1

-1.000

26000

2

2

-6.500 -7.000

2200

3

3

3

-9.200

2600

4

4

4

-11.800

512900

5

5

-24.700

6

6

6-30.100

-Trong thi im kho st, mc nc ngm nm cch MTN 6 m, tc l cao trnh -6. 5m so vi ct 0.00SVTH:NGUYN XUN HNG-MSSV:X070757 TRANG 127

40000



1.2 Bng ch tiu c l ca t nn :h (T/m3) 2.73 2.71 2.74 2.67 2.66 n (T/m3) 1.02 1.02 1.04 1.06 1.08 W (%) 23.9 8 22.2 1 23.4 4 20.6 6 18.05 WL (%) 24.00 36.00 24.00 24.00 WP(%) 23.99 26.93 23.60 21.43 2.73 2.71 2.74 2.67 2.66 0 12.1 7 11.8 0 18.1 0 23.8 3 34.4 2 C (T/m2) 2.07 1.76 3.37 1.04 0.34 qc (T/m2) 122.23 129.60 238.00 566.00 1359.0 0 N 7.00 9.00 14.0 0 17.0 0 25.00 E (T/m2) 856.00 907.00 1666.0 0 1698.0 0 2718.0 0 IL 0.53 0.52 0.40 0.30 -

2. KHI QUT V CC PHNG N MNG -Qua mt ct a cht ta thy : cc lp t pha trn u l nhng lp t yu, kh nng chu nn ln km v khng n nh v cc tnh cht c l. Ch c 2 lp 5 (Ct pha nu long) v 6 (Ct trung ln sn si cht va) l cc lp c kh nng chu c ti trng cng trnh, nht l lp 6 c kh nng chu ti rt tt. Cng vi quy m v ti trng cng trnh ln, gii php mng su l hp l nht. Gii php mng su c th y l mng cc vi mi cc c t vo lp th 6. -C th, trong n ny; s thit k 2 phng n mng cc : CC KHOAN NHI V CC P. 3. C S TNH TON Cc gi thuyt tnh ton : -Ti trng ngang hon ton do cc lp t t y i tr ln tip nhn. -Sc chu ti ca cc trong mng c xc nh nh i vi cc n ng ring r, khng k n nh hng ca nhm cc. -Ti trng ca cng trnh qua i cc ch truyn ln cc cc ch khng trc tip truyn ln phn t nm gia cc cc ti mt tip gip vi i cc. -Khi kim tra cng ca nn t v khi xc nh ln ca mng cc th ngi ta coi mng cc nh mt mng khi quy c bao gm cc v cc phn t gia cc cc. -i cc xem nh tuyt i cng khi tnh ton lc truyn xung cc. Cc loi ti trng dng trong tnh ton : -Mng cng trnh c tnh da theo gi tr ni lc nguy him nht truyn xung chn ct,vch. Tnh ton vi 1 trong 3 t hp c: +(Nmax , MXtu , MYtu , QXtu , QYtu) +(MXmax , MYtu , Ntu , QXtu , QYtu) +(MYmax , MXtu , Ntu , QXtu , QYtu) -Ty theo tnh hnh s liu ri kim tra vi cc t hp cn li.

SVTH:NGUYN XUN HNG-MSSV:X070757

TRANG 128



PHNG N 1 : THIT K MNG CC KHOAN NHI 1. THIT K MNG CC KHOAN NHI DI CT C1 (MNG M1) 1.1 TI TRNG : 1.1.1 Ti trng tnh ton : -Ti trng tnh ton c s dng tnh ton nn mng theo trng thi gii hn th nht. -Da vo bng t hp ni lc chn ct, ta c : Ti trng truyn xung mng theo hai phng X v YLC CHUYN V TM MNG

T hpCOMB1 COMB43 COMB2

Nott (T)1276.930 1037.010 1155.250

MoYtt (T.m)-7.439 -4.318 -34.661

MoXtt (T.m)6.614 102.641 6.685

QoYtt (T)0.020 -1.310 0.030

QoXtt (T)-0.280 -1.000 -3.350

Chn tnh vi t hp 1 (COMB1) v kim tra li vi 2 t hp kia 1.1.2.Ti trng tiu chun -Ti trng tiu chun c s dng tnh ton nn mng theo trng thi gii hn th hai. -Ti trng ln mng tnh c t ETABS l ti trng tnh ton, mun c t hp cc ti trng tiu chun ln mng ng ra phi lm bng t hp ni lc chn ct khc bng cch nhp ti trng tiu chun tc dng ln cng trnh. Tuy nhin, n gin quy phm cho php dng h s vt ti trung bnh n =1,15. Nh vy,ti trng tiu chun nhn c bng cch ly t hp cc ti trng tnh ton chia cho h s vt ti trung bnh. T hpCOMB1 COMB43 COMB2

Nott (T)1110.374 901.748 1004.565

MoYtt (T.m)-6.469 -3.755 -30.140

MoXtt (T.m)5.751 89.253 5.813

QoYtt (T)0.017 -1.139 0.026

QoXtt (T)-0.243 -0.870 -2.913

1.2 CHN CHIU SU CHN I CC V CHIU DI CC -Thit k mt i trng mp trn kt cu sn tng hm ( cao trnh -3.6m so vi ct 0.00 , cao trnh -2.6m so vi mt t t nhin) -Chn chiu cao i mng l h =2m Chiu su t y i tnh t ct t t nhin l -4.6m (tnh t ct 0.00 qui c l -5.6 m). -Chn cc cm su vo lp ct trung ln sn si (lp t 6) on 5.9 m.SVTH:NGUYN XUN HNG-MSSV:X070757 TRANG 129



Chiu di cc l : L =6+2.2+2.6+12.9+5.9 - 4.6 = 25m Kim tra su t y i : - su t y i nh nht c thit k vi yu cu cn bng p lc ngang theo gi thit ti ngang hon ton do lp t trn t y i tip nhn. -Dng Qttmax= 5.14T kim tra iu kin cn bng p lc ngang y i theo cng thc thc nghim sau : tt 2 Qmax hm 0.7 tg (45o ) 2 '.Bm -Trong : + v : Gc ma st trong v dung trng t nhin ca t t y i tr ln, l lp t 2 (st do mm) : o = 12010' =12,170 o ' = 2 T/m3 +Bm: b rng y i. Chn s b Bm = 4.4 m Chiu su t y i ti thiu tnh t mt t t nhin : 12,17 2 5.14 hmin = 0.7 tg (450 ) = 0.4 m 2 2 4.4 Theo thit k, chiu su t y i so vi cao trnh mt t t nhin l hm = 4.6m hm = 4.6m> hmin = 0.4m Tha mn yu cu CHN VT LIU V CC KCH THC CC 1.3.1. Vt liu : -Btng cc B25 c : Rb = 145 kG/cm2, Rbt = 10.5 kG/cm2 -Btng i cc B25c Rb = 145 kG/cm2, Rbt = 10.5 kG/cm2 -Ct thp chu lc trong cc nhm AII c : Rs = 2800 (kG/cm2) -Ct thp chu lc trong i nhm AIII c : Rs = 3650 (kG/cm2) -Ct ai nhm AI c : Ra = 1800 (kG/cm2) 1.3.2 Kch thc cc :

d 2 12 = = 0,785 m2 -Chn cc ng knh : D = 1m Ac = 4 4 -Chn thp dc trong cc : +Cc chu ti trng ngang, hm lng ct thp theo tiu chun : (0.4 0.65)%. +Chn 1420 c din tch 44cm2 (hm lng ct thp : = 0,875%)1.4 TNH SC CHU TI (SCT) CA CC 1.4.1 Sc chu ti theo vt liu lm cc : Q vl = R u A b + R an A a -Trong : +Ru : Cng chu nn tnh ton ca btng cc nhiSVTH:NGUYN XUN HNG-MSSV:X070757 TRANG 130



Vi cc di nc hoc trong dung dch bentonite c : Ru = ln hn 60 (kG/cm2), vi R l mc btng, R = 300 kG/cm2. R 300 Ru = = = 66,7 (kG/cm 2 ) > 60 (kG/cm2 ) 4,5 4,5 Ru = 60 (kG/cm 2 ) +Ab : Din tch tit din ca btng 2 Ab = Ac A a = 7850 40, 72 =7813 cm

R (kG/cm2) v khng 4,5

+Ran : Cng chu nn tnh ton ca ct thp R Khi thp c d 28 mm th Rn = c v khng ln hn 2200 kG/cm2 1,5 R Khi thp c d >28 mm th Rn = c v khng ln hn 2000 kG/cm2 1,5 +Rc : gii hn chy ca ct thp, vi ct thp nhm AII c Rc = 3000 kG/cm2 R 3000 Ran = c = = 2000 kG / cm2 1,5 1,5 +Aa : Din tch tit din ca ct thp dc, Fa = 40,72 (cm2) -Nh vy : Q vl = R u A b + R an Aa = 60 7813 + 2000 40,72 = 550, 2 ( ) T 1.4.2 Sc chu ti theo ch tiu c l ca t nn : Theo ph lc A, TCXD 205 :1998 : - m = 1 : h s iu kin lm vic ca cc trong t - mR , mf : h s diu kin lm vic ca t di mi cc v t mt bn cc + Ly mR = 1 + Ly mf = 0,6 vi cc nhi di nc hoc dung dch bnetonite - qp : cng tnh ton ca t mi cc (T/m2) xc nh theo cng thc: q p = 0.75 ( 'I d p A0 + I LB0 ) k k t mi cc c = 34025v cc cL 25 = = 25 d 1

Qtc = m ( mR .AP .qP + u. mfi . fs .l ) i i

Tra bng A.6 TCXD 205:1998 ta c:0 0 AK = 64,72 ; BK =115,75 ; =0, 689 ; =0,194


TRANG 131



+ I : trng lng trung bnh ca t trn mi cc c k n y ni: 0.9 2 + 0,5 1, 02 + 2, 2 1,02 + 2,6 1,04 +12,9 1,06 +5.9 1,08 I = tb = 1.092 (T / m3 ) = 0.9 + 0.5 + 2.2 + 2.6 +12.9 + 5.9 q p = 0,75 0,194 (1.092 64, 72 + 689 1 0, 1,08 115,57) =3.1 T m 25 2 3 / 2 - Ap = 0,785 m2: din tch tit din ngang mi cc - u = 2 R = 2 x x 0,5 = 3.14m : chu vi mt ct ngang cc Tnh sc chu ti cc hn do ma st thnh cc: - Chia cc lp t thnh cc lp nh c chiu dy 2m. -Tra bng A2 - TCXD 205:1998, ta c: STT 2 3 4 Lp t St xm trng St pha St xm trng li(m)1.40 1.10 1.10 1.30 1.30 2.00 2.00 2.00 2.00 2.00 1.45 1.45 2.00 2.00 1.90

zi(m)5.30 6.55 7.65 8.85 10.15 11.80 13.80 15.80 17.80 19.80 21.53 22.98 24.70 26.70 28.65

IL0.53 0.52 0.52 0.40 0.40 0.30 0.30 0.30 0.30 0.30 0.30 0.30

fsi (T/m2)2.22 2.42 2.51 3.57 3.81 5.28 5.48 5.68 5.88 6.08 6.25 6.40 9.26 9.54 9.81

lsi.fi (T/m)3.11 2.66 2.76 4.64 4.95 10.56 10.96 11.36 11.76 12.16 9.07 9.28 18.52 19.08 18.64 149.50

5

Ct pha

6

Ct ht trung

Tng Sc chu ti tiu chun ca cc theo ch tiu c l ca t nn:Qtc = m ( m R .A P.q P + u. m fi. fs i.l i ) = 1 ( 1 0,785 323.1+ 3.14

Sc chu ti tnh ton ca cc theo ch tiu c l ca t nn:

0,6

149.5 535.3 = T

QaA =

Qtc 535.3 = = 382.4 T K tc 1.4

1.4.3 Sc chu ti theo ch tiu cng ca t nn : Theo ph lc B, TCXD 205 :1998 : Q Q Qa = s + p FSs FS p Trong : FSS = 2: H s an ton thnh phn ma st bnSVTH:NGUYN XUN HNG-MSSV:X070757 TRANG 132



FSp = 3 : H s an ton ca sc chng di mi cc Tnh ma st thnh cc hn Qs :

Qs = uf si li-u = 2 R = 2 x x 0,5 = 3.14m: chu vi mt ct ngang cc - f s = ca + v K s tan a ca = c : lc dnh gia cc v t vp : ng sut hu hiu theo phng thng ng K s = 1 sin : h s p lc ngang trong t

a = 30 : gc ma st gia cc v t nnBng tnh ton thnh phn ma st hng Lp t1 2 3 4 5 6

li (m)0.90 0.50 2.20 2.60 12.90 5.40

ca (T/m2)2.07 2.07 1.76 3.37 1.04 0.34

0.0012.17 12.17 11.75 18.10 23.83 34.42

i (T/m3)2.00 1.02 1.02 1.00 1.06 1.08

vp (T/m2)1.80 2.31 4.55 7.15 20.83 26.66

Ks0.79 0.79 0.80 0.69 0.60 0.43

fs (T/m2)2.30 2.36 2.32 4.70 5.76 7.42

fs.li (T/m)2.07 1.18 5.10 12.22 74.32 40.07 134.96

Qs = u f si li = 3.14 134.96 =423.77 ( T )Tnh sc khng mi cc hn Qp :

Tng

Q p = Ap q pAp = 0.503m2 : din tch tit din ngang mi cc ' q p = c. Nc + vp . N q + .d p . N y Thnh phn th 3 c b qua do n kh b so vi 2 thnh phn cn li, vic b qua ny b cho trng lng cc khng xt vo cng thc c lng sc chu ti. Tra bng 3.5 sch Nn mng ca tc gi Chu Ngc n ng vi : = 34025' c : Nc = 54,79 ; Nq = 38,58 c = 0,34 T/m2 : lc dnh ca t ti mi cc 'vp = 26.06T/m2 : ng sut hu hiu theo phng thng ng ti mi cc, ly kt qu t bng tnh ma st hng trn 2 q p = c. Nc + vp . N a =0,34 54,79 + 26.06 38,58 = 1024 ( T / m ) Q p = Ap x q p = 0,785 1024 = 803.84(T )

Vy sc chu ti ca cc xc nh theo ch tiu cng t nn :


TRANG 133



QaB =

Q Qs 423.77 803.84 + p = + =479.83( T) FS s FS p 2 3

Xc nh sc chu ti thit k ca cc : Ta c : Ptk = min (Qvl , QAa , QBa) = min (550.2 ; 382.4; 479.83) = 382.4(T) Nh vy, chn gi tr Ptk= 382.4(T) tnh ton. 1.5 XC NH S LNG CC V B TR CC Xc nh s lng cc : -Tnh ton vi t hp ni lc c : Dng cng thc chuyn trc vo tm mng ta c ni lc ti tm mng:LC CHUYN V TM MNG


Nott (T)1276.930 1037.010 1155.250

MoYtt (T.m)-7.439 -4.318 -34.661

MoXtt (T.m)6.614 102.641 6.685

QoYtt (T)0.020 -1.310 0.030

QoXtt (T)-0.280 -1.000 -3.350

-p lc tnh ton u cc tc dng ln y i khi khong cch b tr cc cc l 3d : P 382.4 ptt = tk 2 = = 42.49( T / m2 ) 2 (3d ) (3 1) -Din tch s b y i : tt No 1276.93 Fd = tt = = 34.52m 2 p n. tb .h 42.49 1.1 2,5 2 -Trng lng s b i v t trn i : N sb = Fsb tb hd n =34.52 2,5 2 =189.86( T ) 1,1 -S lng cc s b : N tt + N sb 1276.93 + 189.86 nc = K 0 = 1.2 = 4.6 Chn nc = 5 cc Qtk 382.4 1.5.2 B tr cc trong i : Khong cch gia cc tim cc l:>0.3d=300cm khong cch gia tim cc v mp i >0.7d=70cm ly bng 70cm ta c mt bng b tr cc.


TRANG 134



C

6800

D

1500

700

4400 700 700 2000 2000 700 700

3

Fd = 6.8 4.4 = 29.92 ( m2 )tt N d = 1.1 2.5 29.92 2 = 164.56 ( T )

KIM TRA TI TRNG TC DNG LN CC -Kim tra theo iu kin: tt Pmax + Ptt P : cc sc chu ti c tktt Pmin > 0 : cc khng b nh

-Trong : +Trng lng tnh ton ca cc : Pctt = 1.1 2.5 Fc Lc = 1.1 2.5 0.785 25 = 53.97 (T ) +Lc truyn xung cc cc : tt tt N + M Ytt .ximax + M X .yimax tt Pmax = nc xi 2 yi 2Ptt min

N =nc

tt

tt tt M Y .ximax M X .yimax xi2 yi2

Vi :0 N tt = N tt + N tt d tt tt tt M X = M oX + QoY hd tt tt tt M Y = M oY + QoX hd

n = 5 : s lng cc trong i ximax , yimax : khong cch tnh t trc ca hng cc chu nn ln nht n trc i qua trng tm i ximax = 1.5m , y imax = 2.7 mSVTH:NGUYN XUN HNG-MSSV:X070757 TRANG 135

700

1500



xi , yi : khong cch tnh t trc ca hng cc th i n trc i qua trng tm i xi2 = 4 1.52 = 9 m 2

y

2 i

= 4 2.7 2 = 29.16m 2 Bng tnh ton kim tra vi 3 cp ni lcLC CHUYN V TM MNG


Nott (T)1275.080 1035.300 1153.540

MoYtt (T.m)-7.467 -4.113 -34.681

MoXtt (T.m)6.411 104.747 6.518

QoYtt (T)0.020 -1.550 0.020

QoXtt (T)-0.310 -0.900 -3.390


Ntt (T)1439.640 1199.860 1318.100

MXtt (T.m)6.451 101.647 6.558

MYtt (T.m)-8.087 -5.913 -41.461

P ttmax (T)289.75 257.46 268.55

P ttmin (T)286.10 222.48 258.69

Pttmax+Pttc 343.72 311.43 322.52

Ptb287.928 239.972 263.620

tt Qua bng ta thy c 3 cp u c : ( Pmax + Pctt ) < Ptk = 382.4 (T ) t

1.7 KIM TRA IU KIN BIN DNG CA T NN 1.7.1 Kim tra iu kin p lc tiu chun ti y khi mng quy c :tc ptb R tc tc tc Kim tra theo iu kin : pmax 1, 2. R tc pmin 0

Xc nh khi mng quy c :

tb 4 + tb : gc ma st trung bnh ca cc lp t .h 1.4 12.17 o + 2.2 11.75 0 + 2.6 18.10 0 + 12.9 23.83 0+ 5.9 34.4 20 tb = i i = = 240 hi 1.4 + 2.2 + 2.6 + 12.9 + 5.9-Xc nh gc truyn lc = = 240 = 60 4

-Din tch khi mng quy c :


TRANG 136



LM = L1 + 2 H tg = 5 + 2 25 tg 60 =10.26 m BM = B1 + 2 H tg = 2.6 + 2 25 tg 60 = 7.86m FM = LM BM = 10.26 7.86 = 80.64m 2

HM

LM

Khi mng quy c

p lc tiu chun ti y khi mng quy c: -Ti trng tiu chun tc dng ln khi mng quy c: +Trng lng khi t t y i tr ln : N1tc = FM hd tb = 80.64 2 2 = 322.574(T ) +Trng lng khi t t y i n mi cc : tc N 2 = ( FM nc Fc ) i .hi

= (80.64 5 0,785) (0.9 2 + 0,5 1,02 + 2, 2 1,02 + 2,6 1,04 +12,9 1,06 + 5.9 1,08) = 2094.63(T )

+Trng lng bn thn cc cc : tc N 3 = nc b Lc Fc = 5 2.5 25 0.785= 245.31(T ) +Trng lng khi mng quy c : tc tc tc N M = N1tc + N 2 + N 3 = 322.574+ 2094.63+ 245.31= 2662.514(T ) +Tng ti trng tc dng ln khi mng quy c : N tc = N tc + N tc M 0tc tc M X = M tcX + QY hd 0 tc tc M Y = M tc + QX hd 0Y


TRANG 137



-p lc tiu chun ti y khi mng quy c : tc tc tc NM M X MY tc pmax = FM Wx Wy min -Trong : +WX, WY : Momen chng un ca khi mng quy c 7.86 10.26 2 Wx = = 137.9(m 3 ) 6 Wy = 10.26 7.862 = 105.64( m3 ) 6 ptcmax (T/m2)46.93 44.82 46.44

-Ta c bng tnh p lc tiu chun ng vi 3 cp ni lc tiu chun : T hp N0tc M0tcY M0tcX Mtcx Mtcy Ntc (T) (T.m) (T.m) (T.m) (T.m) (T) 5.983 -12.822 3771.28 5.57 COMB1 1108.77 -6.49 59.440 -21.951 3562.77 -3.58 91.08 COMB43 900.26 6.076 -99.367 3665.59 5.67 COMB2 1003.08 -30.16 Cng tiu chun ca t nn ti y khi mng quy c :

ptcmin (T/m2)46.60 43.54 44.47

R tc =

m1.m2 ( A. BM . II + B. H M . ' II +C II. D) K tc

Vi : m1 = 1,4 : h s iu kin lm vic ca nn t + m2 = 1 : h s iu kin lm vic ca cng trnh tc ng qua li vi t nn + Ktc = 1 : h s tin cy ( do c trng tnh ton ly trc tip t th nghim) + II = 1,08 : dung trng lp t t y khi mng qui c tr xung + II = 1,08 : dung trng cc lp t t y khi mng qui c tr ln, ly theo nh tnh ton trn + A, B, D : h s ph thuc vo gc ma st trong nn (y mng quy uc nm lp t th 6 c = 34,420.Tra bng 2.1 trang 64 Sch Nn v Mng (Nguyn Vn Qung), ta c : A = 1,6 ; B = 7,43 ; D = 9,37 1, 4 1 R tc = ( 1,6 11.16 1,08 + 7, 43 25 1,08 + 0,34 9,37) = 312.3(T / m2 ) Nh 1 tc ptb Rtc = 312.3(T / m2 ) tc tc 2 vy cc t hp u c : pmax 1, 2. R = 374.8 (T / m ) tc pmin 0 Vy khi mng quy c tha iu kin v p lc. Ta c th tnh ton c ln ca nn theo quan nim nn bin dng tuyn tnh


TRANG 138



Kim tra ln ca nn : -Kim tra ln vi t hp COMB1 c : ptcmax =46.93 (T/m2) v ptcmin = 46.6 (T/m2) -ng sut trung bnh ti y khi mng quy c : tc tc pmax + pmin 46.93 + 46.6 tc tc tb = ptb = = = 46.765(T / m 2 ) 2 2 -ng sut bn thn ti y khi mng quy c : bt = vp = 26.66 (T/m2 ) theo nh tnh ton trn -ng sut gy ln ti y khi mng quy c : tc zgl 0 = tb bt = 45.765 26.66 = 20.105(T/m 2 ) = -Ti su z(m) k t y khi mng qui c : zbt = bt + dn z = 26.66 + 1,08 z -Ti su z(m) k t y khi mng qui c : zgl = Ko zgl=0 = Ko 20.105 +K0 : tra bng 2.7 sch Nn v mng cc cng trnh dn dng v cng nghip ca tc gi Nguyn Vn Qung Tnh ln : -Chia nn t khi quy c thnh cc lp t c chiu dy 2 m (< B/4 = 2,4225m) -Phm vi chu ln tnh n su ng sut gy ln bng 0,2 ng sut do trng lng bn thn ca t gy ra. n S = i zglhi Cng thc tnh ln khi khng k n n hng hn ch ca t : i i =1 Ei -Bng tnh ln ca nn khi khi mng quy c : vi = 0.8 ; Ei =2718 T/m2:im 0 1 2 3 4 4 su (m) 0.000 2.000 4.000 6.000 8.000 10.000 LM/BM 1.305 1.305 1.305 1.305 1.305 1.305 2z/BM 0.000 0.509 1.018 1.527 2.036 2.545 Ko 0.000 0.992 0.899 0.699 0.504 0.366 zgl (t/m2) 0.000 19.941 18.074 14.059 10.143 7.358 zbt (T/m2) 26.660 28.820 30.980 33.140 35.300 37.460 T s 0.000 0.692 0.583 0.424 0.287 0.196 tbgl (T/m2) 9.971 19.008 16.066 12.101 8.750 ln (m) 0.006 0.011 0.009 0.007 0.005 0.039

Tng -Ta c ln ca nn S =3.9cm < Sgh = 8 cm -Vy nn t m bo yu cu v bin dng. 1.8 TNH TON V CU TO I CC


TRANG 139



Kim tra chc thng : -V thp chc thng, ta c thp chc thng ph bn ngoi cc cc nn khng cn kim tra chc thng.600

2000

45 0'

4400

Tnh ton ct thp i cc : -Cc mt ct ngm quy c tnh ton i mng M1 :C

6800

D

1500

700

4400 700 700 2000 2000 700 700tt

3

tt tt N tt M y .xi M x . yi -Lc truyn xung cc cc : Pi = n xi2 yi2 -Tnh vi t hp COMB11 c : MXtt MYtt P ttmax T hp Ntt (T) P ttmin (T) (T.m) (T.m) (T)

700

1500

Pttmax+Pttc 343.72 311.43 322.52

Ptb287.928 239.972 263.620

COMB1 COMB4 3 COMB2

1439.640 1199.860 1318.100

6.451 101.647 6.558

-8.087 -5.913 -41.461

289.75 257.46 268.55

286.10 222.48 258.69

Ct thp theo mt ngm I-I :SVTH:NGUYN XUN HNG-MSSV:X070757 TRANG 140



700 700

2000

2000

700 700

2P

tb

P

tb

2P

tb

M men tng ng vi mt ngm I-I : Din tch tit din ngang thp chu mmen MII (t lp di) :M II 403.10 10 5 FaII = = = 66.33 (cm 2 ) 0,9 x h0 x Ra 0,9 185 3650

Chn 2718 c Fa =68.7cm2 Khong cch gia tim 2 ct thp cnh nhau : 18a160mm Ct thp theo mt ngm II-II :

12002PM I = r 2 Ptb = 1.2x2x287.928=691.03 T.mtb

700

M men tng ng vi mt ngm II-II: Din tch tit din ngang thp chu mmen MII (t lp trn) :FaII = M II 691.03 10 5 = = 113.7 (cm 2 ) 0,9 x h0 x Ra 0,9 185 3650

Chn 3720 c Fa =116.24cm2 Khong cch gia tim 2 ct thp cnh nhau : 20a180mm 2. THIT K MNG CC KHOAN NHI DI VCH (MNG M2)


TRANG 141

GVHD KC :C BCH V HONG LAN N TT NGHIP KSXD KHA 2007-2012B


700

1

2

4400 3000

3

700

4700 1500 1500 4400

3700

Mng M2 2.1 TI TRNG : 2.1.Ti trng tnh ton : -Ti trng tnh ton c s dng tnh ton nn mng theo trng thi gii hn th nht. -Khi tnh ton bng ETABS, phc v cho vic tnh mng; ta gn chung cho c vch cn tnh mng vo 1 Pier. T kt qu ni lc Pier my xut ra , ta c :T hpCOMB78 COMB77 COMB52

No (T)748.77 705.38 557.97

tt

MoY (T.m)-1.1 -2.803 4.799

tt

MoX (T.m)91.781 139.959 75.37

tt

QoY (T)96.74 84.22 59.5

tt

QoX (T)-0.76 -2.02 3.74

tt

Ti trng truyn xung mng theo hai phng X v Y Chn tnh vi t hp 1 (COMB11) v kim tra li vi 2 t hp kia 2.2 Ti trng tiu chun tc tc tc tc T hp No (T) MoY (T.m) MoX (T.m) QoY (T)COMB78 COMB77 COMB52651.104 613.374 485.191 -0.957 -2.437 4.173 79.810 121.703 65.539 84.122 73.235 51.739

QoX (T)-0.661 -1.757 3.252

tc

Chn chiu su chn i cc, kch thc v vt liu lm cc hon ton nh mng M1. Xc nh sc chu ti thit k ca cc : -Ta c : Ptk = min (Qvl , QAa , QBa) = min (550.2 ; 382.4; 479.83) = 382.4(T) Nh vy, chn gi tr Ptk= 382.4(T) tnh ton


TRANG 142



2.3 XC NH S LNG CC V B TR CC Xc nh s lng cc : -Tnh ton vi t hp ni lc COMB1 c :T hpCOMB78 COMB77 COMB52

No (T)748.77 705.38 557.97

tt

MoY (T.m)-1.1 -2.803 4.799

tt

MoX (T.m)91.781 139.959 75.37

tt

QoY (T)96.74 84.22 59.5

tt

QoX (T)-0.76 -2.02 3.74

tt

-p lc tnh ton u cc tc dng ln y i khi khong cch b tr cc cc l 3d : P 382.4 ptt = tk 2 = = 42.49 ( T / m2 ) 2 (3d ) (3 1) -Din tch s b y i : tt No 748.77 Fd = tt = = 20.24m 2 p n. tb .h 42.49 1.1 2.5 2 -Trng lng s b i v t trn i : N sb = Fsb tb hd n = 20.24 2.5 2 =111.32( T) 1.1 -S lng cc s b : tt N 0 + N sb 748.77 + 111.32 nc = K = 1.4 = 3.15 Chn nc = 4 cc Qtk 382.4 2.5.2 B tr cc trong i :B

700

1

2

4400 3000

3

700

4700 1500 1500 4400

3700

Fd = 4.4 4.4 = 19.36 ( m2 )tt N d = 1.1 2.5 19.36 2 = 106.48( T )

1.6 KIM TRA TI TRNG TC DNG LN CC 2 Kim tra theo iu kin: tt Pmax + Ptt P : cc sc chu ti c tkSVTH:NGUYN XUN HNG-MSSV:X070757 TRANG 143

GVHD KC :C BCH V HONG LAN N TT NGHIP KSXD KHA 2007-2012tt Pmin > 0 : cc khng b nh


-Trong : +Trng lng tnh ton ca cc : Pctt = 1.1 2.5 Fc Lc = 1.1 2.5 0.785 25 = 53.97 (T ) +Lc truyn xung cc cc : tt tt N + M Ytt .ximax + M X .yimax tt Pmax = nc xi 2 yi 2Ptt min

N =nc

tt

tt tt M Y .ximax M X .yimax xi2 yi2

Vi :0 tt N tt = N tt + N d tt tt tt M X = M oX + QoY hd tt tt tt M Y = M oY + QoX hd

n = 4 : s lng cc trong i ximax , yimax : khong cch tnh t trc ca hng cc chu nn ln nht n trc i qua trng tm i ximax = 1.5m , y imax = 1.5 m xi , yi : khong cch tnh t trc ca hng cc th i n trc i qua trng tm i xi2 = 4 1.52 = 9 m2

y

2 i

= 4 1.52 = 9 m2N (T)855.250 811.860 664.450tt

T hpCOMB78

MX (T.m)236.891 266.289 164.62

tt

MY (T.m)-2.24 -5.833 10.409

tt

P

tt

m ax

(T)

P

tt

min

(T)

P

tt

tt m ax+P c

COMB77 COMB52

253.67 248.32 195.28

173.96 157.61 136.94

307.64 302.29 249.25

Bng tnh ton kim tra vi 3 cp ni lctt Qua bng ta thy c 3 cp u c : ( Pmax + Pctt ) < Ptk = 382.4(T ) t

1.7 KIM TRA IU KIN BIN DNG CA T NN 1.7.1 Kim tra iu kin p lc tiu chun ti y khi mng quy c :tc ptb R tc tc tc Kim tra theo iu kin : pmax 1, 2. R tc pmin 0

Xc nh khi mng quy c :SVTH:NGUYN XUN HNG-MSSV:X070757 TRANG 144



tb 4 + tb : gc ma st trung bnh ca cc lp t i .hi = 1.4 12.17 o + 2.2 11.75 0 + 2.6 18.10 0+ 12.9 23.83 0+ 5.9 34.4 20= 240 tb = hi 1.4 + 2.2 + 2.6 + 12.9 + 5.9-Xc nh gc truyn lc = 240 = = 60 4 -Din tch khi mng quy c : LM = L1 + 2 H tg = 3 + 2 25 tg 60 = 8.26 m

BM = B1 + 2 H tg

= 3 + 2 25 tg 60 = 8.26m

FM = LM BM = 8.26 8.26 = 68.23m 2

HM

LM

Khi mng quy c p lc tiu chun ti y khi mng quy c: -Ti trng tiu chun tc dng ln khi mng quy c: + Trng lng khi t t y i tr ln : N1tc = FM hd tb = 68.23 2 2 = 272.91(T ) + Trng lng khi t t y i n mi cc : tc N 2 = ( FM nc Fc ) i.h i +12.9 1.06 + 5.9 1.08) = 1777.22(T ) + Trng lng bn thn cc cc :SVTH:NGUYN XUN HNG-MSSV:X070757 TRANG 145

= (68.23 4 0.785) (0.9 2 + 0.5 1.02 + 2.2 1.02 + 2.6 1.04



tc N 3 = nc b Lc Fc = 4 2,5 25 0,785= 196.25 (T )

+ Trng lng khi mng quy c : tc tc tc N M = N1tc + N 2 + N3 = 272.91+ 1777.22 + 196.25 = 2246.38(T ) + Tng ti trng tc dng ln khi mng quy c : tc N tc = N M + N tc 0tc tc tc M X = M 0 X + QY hd tc tc tc M Y = M 0Y + QX hd

-p lc tiu chun ti y khi mng quy c :tc pmax = min tc tc tc NM M X MY FM Wx Wy

-Trong : +WX, WY : Momen chng un ca khi mng quy c 8.26 8.26 2 Wx = = 93.93(m 3 ) 6 8.26 8.26 2 Wx = = 93.93(m 3 ) 6 -Ta c bng tnh p lc tiu chun ng vi 3 cp ni lc tiu chun : T hp N0tc (T) M0tcY (T.m)-0.96 -2.44 4.17

M0tcX (T.m)79.81 121.70 65.54

Mtcx (T.m)2351.097 2099.043 1462.49 6

Mtcy (T.m)-18.800 -49.863 91.982

Ntc (T)2897.48 2859.75 2731.57

ptcmax (T/m2)67.70 64.79 56.58

ptcmin (T/m2)17.24 19.04 23.49

COMB78 651.10 COMB77 613.37 COMB52 485.19

Cng tiu chun ca t nn ti y khi mng quy c :

R tc =

m1.m2 ( A. BM . II + B. H M . ' II +C II. D) K tc

Vi : m1 = 1,4 : h s iu kin lm vic ca nn t + m2 = 1 : h s iu kin lm vic ca cng trnh tc ng qua li vi t nn + Ktc = 1 : h s tin cy ( do c trng tnh ton ly trc tip t th nghim) + II = 1,08 : dung trng lp t t y khi mng qui c tr xung + II = 1,08 : dung trng cc lp t t y khi mng qui c tr ln, ly theo nh tnh ton trn


TRANG 146



+A, B, D : h s ph thuc vo gc ma st trong nn (y mng quy uc nm lp t th 6 c = 34,420.Tra bng 2.1 trang 64 Sch Nn v Mng (Nguyn Vn Qung), ta c : A = 1,6 ; B = 7,43 ; D = 9,37 1, 4 1 R tc = ( 1,6 11.16 1,08 + 7, 43 25 1,08 + 0,34 9,37) = 312.3(T / m2 ) Nh 1 tc ptb R tc = 312.3(T / m2 ) tc tc 2 vy cc t hp u c : pmax 1, 2.R = 374.8 (T / m ) tc pmin 0 Vy khi mng quy c tha iu kin v p lc. Ta c th tnh ton c ln ca nn theo quan nim nn bin dng tuyn tnh Kim tra ln ca nn : -Kim tra ln vi t hp COMB1 c : ptcmax =67.7(T/m2) v ptcmin = 17.24(T/m2) -ng sut trung bnh ti y khi mng quy c : tc tc pmax + pmin 67.7 + 17.24 tc tc tb = ptb = = = 42.47(T / m 2 ) 2 2 -ng sut bn thn ti y khi mng quy c : bt = vp = 26.66 (T/m2 ) theo nh tnh ton trn -ng sut gy ln ti y khi mng quy c : tc zgl 0 = tb bt = 42.47 26.66 = 15.81(T/m2 ) = -Ti su z(m) k t y khi mng qui c : zbt = bt + dn z = 26.66 + 1,08 z -Ti su z(m) k t y khi mng qui c : zgl = Ko zgl=0 = Ko 15.81 +K0 : tra bng 2.7 sch Nn v mng cc cng trnh dn dng v cng nghip ca tc gi Nguyn Vn Qung Tnh ln : -Chia nn t khi quy c thnh cc lp t c chiu dy 2 m (< B/4 = 2,4225m) -Phm vi chu ln tnh n su ng sut gy ln bng 0,2 ng sut do trng lng bn thn ca t gy ra. n i gl Cng thc tnh ln khi khng k n n hng hn ch ca t : S = zi hi i =1 Ei -Bng tnh ln ca nn khi khi mng quy c : vi = 0.8 ; Ei =2718 T/m2:


TRANG 147



im 0.000 1.000 2.000 3.000 4.000

su (m) 0.000 2.000 4.000 6.000 8.000

LM/BM 1.000 1.000 1.000 1.000 1.000

2z/BM 0.000 0.484 0.969 1.453 1.937

Ko 0.000 0.942 0.741 0.530 0.375

zgl zbt (t/m2) (T/m2) 0.000 26.660 14.896 28.820 11.720 30.980 8.386 33.140 5.932 35.300

T s 0.000 0.517 0.378 0.253 0.168

tbgl (T/m2) 7.448 13.308 10.053 7.159

Tng -Ta c ln ca nn S =2.2cm < Sgh = 8 cm Vy nn t m bo yu cu v bin dng. 1.8 TNH TON V CU TO I CC

ln (m) 0.004 0.008 0.006 0.004 0.022

Kim tra chc thng : -V thp chc thng, ta c thp chc thng ph bn ngoi cc cc nn khng cn kim tra chc thng. 300

2000

45 0'

4400

Tnh ton ct thp i cc : -Cc mt ct ngm quy c tnh ton i mng M1 :B

700

1

2

4400 3000

3

700

4700 1500 1500 4400

3700


TRANG 148



tt tt N tt M y .xi M x . yi -Lc truyn xung cc cc : Pi = n xi2 yi2 -Tnh vi t hp COMB11 c : tt

T hpCOMB78

N (T) MX (T.m)MY (T.m)P855.250 811.860 664.450 236.891 266.289 164.62 -2.24 -5.833 10.409

tt

tt

tt

tt

max

(T) P

tt

min

(T) P

tt

tt max +P c

P

tb

COMB77 COMB52 Ct thp theo mt ngm I-I :

253.67 248.32 195.28

173.96 157.61 136.94

307.64 302.29 249.25

213.813 202.965 166.113

13502PM men tng ng vi mt ngm I I :

700

tb

M I = r1 2 PTB ) = 1.35 2 213.813 = 577.3(T .m)Chn a = 15cm ho = 200 15 = 185 (cm) Din tch tit din ngang thp chu mmen MI :FaI = MI 577.3 10 5 = = 94.99 (cm 2 ) 0,9 x h0 x Ra 0,9 185 3650

Chn 2522 c Fa =95cm2 Khong cch gia tim 2 ct thp cnh nhau : 175mm M men tng ng vi mt ngm IIII :

4002PtbM I = r1 2 PTB = 0.4 2 213.813 = 171(T .m)

700

Chn a = 15cm ho = 200 15 = 185 (cm)SVTH:NGUYN XUN HNG-MSSV:X070757 TRANG 149



Din tch tit din ngang thp chu mmen MI :FaI = MI 171 105 = = 28.14 (cm 2 ) 0,9 x h0 x Ra 0,9 185 3650

Chn 2014 c Fa =95cm2=>t thp theo cu to Khong cch gia tim 2 ct thp cnh nhau : 200mm


TRANG 150

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