1

Bi tp ln

C hc t. bi:

Mng bng di tng b rng bb v mng n di ct b rng b, b di l chn su h pha ngoi nh. t nn gm 1 lp st pha c chiu dy cha kt thc trong h khoan thm d su 16m. iu kin t v mng nh hnh v v cc bng.

Ni lc:

- Ti nh mng n: lc dc tcN0 (kN), tcM 0 (kNm),

tcQ0 (kN).

- Ti nh mng bng: lc dc tcbN0 (kN/m), tcbM 0 (kNm/m).

Tnh ln ca cc im O, N y mng n v J y mng bng c k n nh hng ti trng ca cc mng ln cn.

Kim tra nn v sc chu ti. Bit h s an ton Fs = 2.

M s bi: 13XIII S liu mng V ti trng

h (m) l (m) b (m) t (m) bb (m)tcN0

(kN)

tcM 0 (kNm)

tcQ0

(kN)

tcbN0

(kN/m)

tcbM 0

(kNm/m)

1,6 2,4 1,9 0,3 1,2 850 87 18 170 16

Ch tiu c l ca t

(kN/m3)

s (kN/m3)

W

(%)

WL

(%)

WP

(%)

C (kPa)

()

E0 (kPa)

18,5 26,7 30 37 24 21 18 9840

2

Bi lm 1. nh gi iu kin a cht cng trnh, a cht thu vn :

t nn gm mt lp st pha c chiu dy cha kt thc trong h khoan

thm d su 15m. Mc nc ngm su 1,6m so vi mt t t nhin.

( )876,01

5,18)30.01,01(7,261

01,01. =+=+= We s

3/90,8876,01

107,261

mkNews

dn =+=+

= t c st l:

0,461524372430 =

==

PL

PL WW

WWI

Ta thy IL = 0,4615 nn t trng thi do cng, c moun bin dng

E0 = 9840 kPa t trung bnh. 2. Xc nh ti trng tiu chun tc dng ti tm din tch mng.

+ Mng n trc 4E:

Ntc = tcN0 = 850kN

Mtc = tcM 0 + tcQ0 .hm = 87 + 18.0,7 = 99,6kNm

Qtc = tcQ0 = 18kN

+ Mng bng:

Nbtc = tcbN0 = 170kN

Mbtc = tcbM 0 = 16kNm/m

3. p lc tiu chun ti y mng. + Mng n trc 4E:

'61.min

max hle

blN

tbl

tc +

=

mNMe tc

tc

l 0,1178506,99 === ; mhhh ngoaitrong 825,1

26,105,2

2' =+=+=

825,1.204,2

0,117.619,1.4,2

850minmax

+

=tc kPatc 277,4265

max=

kPatc 168,3805min

=

3

kPatctc

tctb 222,90352

3805,1684265,2772

minmax =+=+= + Mng bng:

'61.minmax

hbe

blN

tbb

tcbtc +

=

mNMe tc

b

tcb

b 0941,017016 === ; mhhh ngoaitrong 825,1

26,105,2

2' =+=+=

825,1.202,1

0,0941.612,1.1

170minmax

+

=tc kPatc 244,8208

max=

kPatc 111,5125min

= kPa

tctctctb 178,16672

111,51258208,2442

minmax =+=+=

4. Kim tra iu kin p lc ti y mng:

R=Ktc

mm 21 (AbII + BhII + DcII) m1; m2 tra bng c m1 = 1,2; m2 = 1,0. S liu a cht c ly t kt qu th nghim trong phng nn Ktc = 1,0

= 180 tra bng A = 0,43; B = 2,72; D = 5,31 II = n = 8,90kN/m3; II = = 18,5kN/m3; cII = 21kPa; h = 1,6m

+ Mng n:

4

b = 1,9m

R =1

1.2,1 (0,43 . 1,9 . 8,90 + 2,72 . 1,6 . 18,5 + 5,31 . 21)

= 239,152kPa

=

5

ABCDglzABCD

glz KKIi 000 3035,193)( == =

Trong : ABCD0K : tra bng ph thuc l/b v 2z/b vi l = 2,4m; b = 1,9m. Cc kt qu tnh ton c lp thnh bng:

6

Bng 1 - Xc nh ng sut gy ln ti O do ti trng trn mng trc 4E

im z (m) l/b 2z/b KoABCD )I(glz (KPa) btz (KPa) 0 0 1.2632 0 1.0000 193.3037 29.600 1 0.38 1.2632 0.4 0.9693 187.3728 32.982 2 0.76 1.2632 0.8 0.8367 161.7339 36.364 3 1.14 1.2632 1.2 0.6624 128.0407 39.746 4 1.52 1.2632 1.6 0.5086 98.3065 43.128 5 1.9 1.2632 2 0.3907 75.5198 46.510 6 2.28 1.2632 2.4 0.3042 58.8023 49.892 7 2.66 1.2632 2.8 0.2411 46.5959 53.274 8 3.04 1.2632 3.2 0.1944 37.5877 56.656 9 3.42 1.2632 3.6 0.1595 30.8307 60.038 10 3.8 1.2632 4 0.1328 25.6721 63.420 11 4.18 1.2632 4.4 0.1121 21.6652 66.802 12 4.56 1.2632 4.8 0.0957 18.5022 70.184 13 4.94 1.2632 5.2 0.0826 15.9682 73.566 14 5.32 1.2632 5.6 0.0720 13.9106 76.948 15 5.7 1.2632 6 0.0632 12.2193 80.330 16 6.08 1.2632 6.4 0.0559 10.8139 83.712 17 6.46 1.2632 6.8 0.0498 9.6343 87.094 18 6.84 1.2632 7.2 0.0447 8.6353 90.476 19 7.22 1.2632 7.6 0.0403 7.7822 93.858 20 7.6 1.2632 8.0 0.0365 7.0483 97.240 21 7.98 1.2632 8.4 0.0332 6.4125 100.622 22 8.36 1.2632 8.8 0.0303 5.8583 104.004 23 8.74 1.2632 9.2 0.0278 5.3723 107.386 24 9.12 1.2632 9.6 0.0256 4.9440 110.768 25 9.5 1.2632 10 0.0236 4.5646 114.150 26 9.88 1.2632 10.4 0.0219 4.2270 117.532 27 10.26 1.2632 10.8 0.0203 3.9253 120.914 28 10.64 1.2632 11.2 0.0189 3.6546 124.296 29 11.02 1.2632 11.6 0.0176 3.4108 127.678 30 11.4 1.2632 12 0.0165 3.1905 131.060

6.1.2 Xc nh ng sut gy ln ti cc im nm trn trc ng qua O do ti trng ca mng trc 3E v 5E. Mng trc 3E v 5E i xng nhau qua O nn ta tnh ng sut gy ln ti cc im nm trn trc ng qua O do ti trng ca mng trc 3E sau nhn vi 2 k n ti trng ca mng trc 5E. ng sut gy ln ti cc im nm trn trc ng qua O do mng trc 3E v 5E:

7

)(214,773

).(3035,193.2.2)(2.2)( 0

gKGNOgIENO

gKGNOgIENOglzgKGNOgIENO

glz

KK

KKKKIIi

=== =

Trong : gIENOK : tra bng ph thuc l/b v z/b vi b = 1,2m; l = 4,25m. gKGNOK : tra bng ph thuc l/b v z/b vi b=1,2m; l = 2,35m.

Cc kt qu tnh ton c lp thnh bng: Bng 2 - Xc nh ng sut gy ln )II(glz

im z (m) z/b Tra gIENOK Tra gKGNOK )II(glz

(KPa) l/b gIENOK l/b gKGNOK 0 0 0.0000 3.54167 0.2500 1.9583 0.2500 0 1 0.38 0.3167 3.54167 0.2470 1.9583 0.2468 0.150722 0.76 0.6333 3.54167 0.2319 1.9583 0.2305 1.064263 1.14 0.9500 3.54167 0.2080 1.9583 0.2042 2.963134 1.52 1.2667 3.54167 0.1826 1.9583 0.1754 5.511275 1.9 1.5833 3.54167 0.1594 1.9583 0.1488 8.169776 2.28 1.9000 3.54167 0.1394 1.9583 0.1258 10.50737 2.66 2.2167 3.54167 0.1225 1.9583 0.1066 12.30298 3.04 2.5333 3.54167 0.1082 1.9583 0.0907 13.51069 3.42 2.8500 3.54167 0.0961 1.9583 0.0777 14.1874

10 3.8 3.1667 3.54167 0.0857 1.9583 0.0670 14.432511 4.18 3.4833 3.54167 0.0767 1.9583 0.0582 14.351512 4.56 3.8000 3.54167 0.0690 1.9583 0.0508 14.038813 4.94 4.1167 3.54167 0.0623 1.9583 0.0447 13.570814 5.32 4.4333 3.54167 0.0564 1.9583 0.0396 13.006615 5.7 4.7500 3.54167 0.0513 1.9583 0.0352 12.389516 6.08 5.0667 3.54167 0.0467 1.9583 0.0315 11.750517 6.46 5.3833 3.54167 0.0427 1.9583 0.0284 11.111218 6.84 5.7000 3.54167 0.0392 1.9583 0.0256 10.485919 7.22 6.0167 3.54167 0.0360 1.9583 0.0233 9.8835920 7.6 6.3333 3.54167 0.0332 1.9583 0.0212 9.3098921 7.98 6.6500 3.54167 0.0307 1.9583 0.0194 8.7676622 8.36 6.9667 3.54167 0.0285 1.9583 0.0178 8.258 23 8.74 7.2833 3.54167 0.0265 1.9583 0.0164 7.7808424 9.12 7.6000 3.54167 0.0246 1.9583 0.0151 7.3353225 9.50 7.9167 3.54167 0.0230 1.9583 0.0140 6.9201126 9.88 8.2333 3.54167 0.0215 1.9583 0.0130 6.5335927 10.26 8.5500 3.54167 0.0201 1.9583 0.0121 6.1740128 10.64 8.8667 3.54167 0.0189 1.9583 0.0113 5.8395829 11.02 9.1833 3.54167 0.0177 1.9583 0.0106 5.528530 11.4 9.5000 3.54167 0.0167 1.9583 0.0099 5.23906

8

6.1.3 Xc nh ng sut gy ln ti cc im nm trn trc ng qua O do ti trng ca mng bng. ng sut gy ln ti cc im nm trn trc ng qua O do mng bng gy ra: z

glzz

glz KKIIIi .5667,148)( 0 == =

Trong : zK : tra bng ph thuc x/b v z/b vi b = 1,2m; x = 2,1m. Cc kt qu tnh ton c lp thnh bng:

Bng 3 - Xc nh ng sut gy ln )III(glz im z (m) x/b z/b Kz )III(glz (KPa)

0 0 1.75 0.0000 0.0000 0.0000 1 0.38 1.75 0.3167 0.0026 0.3898 2 0.76 1.75 0.6333 0.0166 2.4701 3 1.14 1.75 0.9500 0.0404 6.0035 4 1.52 1.75 1.2667 0.0658 9.7799 5 1.9 1.75 1.5833 0.0871 12.9383 6 2.28 1.75 1.9000 0.1023 15.1995 7 2.66 1.75 2.2167 0.1119 16.6221 8 3.04 1.75 2.5333 0.1170 17.3818 9 3.42 1.75 2.8500 0.1189 17.6615

10 3.8 1.75 3.1667 0.1185 17.6124 11 4.18 1.75 3.4833 0.1168 17.3475 12 4.56 1.75 3.8000 0.1141 16.9475 13 4.94 1.75 4.1167 0.1108 16.4680 14 5.32 1.75 4.4333 0.1073 15.9464 15 5.7 1.75 4.7500 0.1037 15.4078 16 6.08 1.75 5.0667 0.1001 14.8686 17 6.46 1.75 5.3833 0.0965 14.3392 18 6.84 1.75 5.7000 0.0931 13.8261 19 7.22 1.75 6.0167 0.0897 13.3329 20 7.6 1.75 6.3333 0.0866 12.8617 21 7.98 1.75 6.6500 0.0836 12.4132 22 8.36 1.75 6.9667 0.0807 11.9874 23 8.74 1.75 7.2833 0.0780 11.5838 24 9.12 1.75 7.6000 0.0754 11.2017 25 9.50 1.75 7.9167 0.0730 10.8400 26 9.88 1.75 8.2333 0.0707 10.4976 27 10.26 1.75 8.5500 0.0685 10.1735 28 10.64 1.75 8.8667 0.0664 9.8665 29 11.02 1.75 9.1833 0.0645 9.5756 30 11.4 1.75 9.5000 0.0626 9.2997

9

6.1.4 V biu ng sut bn thn v ng sut gy ln ti im O. Bng 4 - Xc nh ng sut gy ln ti im O

im z (m) )I(glz (KPa)

)II(glz (KPa)

)III(glz (KPa)

Oglz (KPa)

btz

(KPa)

0 0 193.3037 0.0000 0.0000 193.3037 29.6 1 0.38 187.3728 0.1507 0.3898 187.9133 32.982 2 0.76 161.7339 1.0643 2.4701 165.2683 36.364 3 1.14 128.0407 2.9631 6.0035 137.0073 39.746 4 1.52 98.3065 5.5113 9.7799 113.5977 43.128 5 1.9 75.5198 8.1698 12.9383 96.6279 46.51 6 2.28 58.8023 10.5073 15.1995 84.5091 49.892 7 2.66 46.5959 12.3029 16.6221 75.5209 53.274 8 3.04 37.5877 13.5106 17.3818 68.4801 56.656 9 3.42 30.8307 14.1874 17.6615 62.6796 60.038 10 3.8 25.6721 14.4325 17.6124 57.7170 63.42 11 4.18 21.6652 14.3515 17.3475 53.3642 66.802 12 4.56 18.5022 14.0388 16.9475 49.4885 70.184 13 4.94 15.9682 13.5708 16.4680 46.0070 73.566 14 5.32 13.9106 13.0066 15.9464 42.8636 76.948 15 5.7 12.2193 12.3895 15.4078 40.0166 80.33 16 6.08 10.8139 11.7505 14.8686 37.4330 83.712 17 6.46 9.6343 11.1112 14.3392 35.0847 87.094 18 6.84 8.6353 10.4859 13.8261 32.9473 90.476 19 7.22 7.7822 9.8836 13.3329 30.9987 93.858 20 7.6 7.0483 9.3099 12.8617 29.2199 97.24 21 7.98 6.4125 8.7677 12.4132 27.5934 100.622 22 8.36 5.8583 8.2580 11.9874 26.1037 104.004 23 8.74 5.3723 7.7808 11.5838 24.7369 107.386 24 9.12 4.9440 7.3353 11.2017 23.4810 110.768 25 9.50 4.5646 6.9201 10.8400 22.3247 114.150 26 9.88 4.2270 6.5336 10.4976 21.2582 117.532 27 10.26 3.9253 6.1740 10.1735 20.2728 120.914 28 10.64 3.6546 5.8396 9.8665 19.3607 124.296 29 11.02 3.4108 5.5285 9.5756 18.5149 127.678 30 11.4 3.1905 5.2391 9.2997 17.7293 131.060

Biu ng sut gy ln v ng sut bn thn ca cc im nm trn trc ng qua O c th hin trn hnh v trang 10.

6.1.5 Tnh ton ln ti im O.

10

Gii hn nn tnh n im 25 c: kPakPa btgl 83,2215,114.2,0.2,03447,22 ==

11

6.2 Tnh ln ti im N. ng sut gy ln ti cc im nm trn trc ng qua N gm: + ng sut gy ln do ti trng ca mng trc 4E. + ng sut gy ln do ti trng ca mng trc 3E & 5E. + ng sut gy ln do ti trng ca mng bng. Chia nn di mng thnh nhng phn t c chiu dy hi = 0,38m. 6.2.1 Xc nh ng sut gy ln ti cc im nm trn trc ng qua N do ti trng ca mng trc 4E. ng sut gy ln ti cc im nm trn trc ng qua N:

gDANMgDANMglzgDANM

glz KKKAi 386,6073035,193.22)( 0 === =

Trong : gDANMK : tra bng ph thuc l/b v z/b vi b = 0,95m; l = 2,4m. Cc kt qu tnh ton c lp thnh bng 5 trang 12. 6.2.2 Xc nh ng sut gy ln ti cc im nm trn trc ng qua N do ti trng ca mng trc 3E v 5E. Mng trc 3E v 5E i xng nhau qua N nn ta tnh ng sut gy ln ti cc im nm trn trc ng qua N do ti trng ca mng trc 3E sau nhn vi 2 k n ti trng ca mng trc 5E. ng sut gy ln ti cc im nm trn trc ng qua N do mng trc 3E & 5E:

)(607,386

).(3035,193.2)(2)( 0

gFGNMgHENM

gFGNMgHENMglzgFGNMgHENM

glz

KK

KKKKBi

=== =

Trong : gHENMK : tra bng ph thuc l/b v z/b vi b = 2,4m; l = 4,25m. gFGNMK : tra bng ph thuc l/b v z/b vi b = 2,35m; l = 2,4m. Cc kt qu tnh ton c lp thnh bng 6 trang 13. 6.2.3 Xc nh ng sut gy ln ti cc im nm trn trc ng qua N do ti trng ca mng bng. ng sut gy ln ti cc im nm trn trc ng qua N do mng bng gy ra:

zglzz

glz KKCi 5667,148)( 0 == =

Trong : zK : tra bng ph thuc x/b v z/b vi b = 1,2m; x = 0,9m.

Cc kt qu tnh ton c lp thnh bng 7 trang 14.

12

Bng 5 - Xc nh ng sut gy ln )A(glz

im z (m) z/b l/b KgDANM )A(glz (KPa) btz (KPa)0 0 0.00 2.5263 0.2500 96.6518 29.6

1 0.38 0.40 2.5263 0.2442 94.3922 32.982

2 0.76 0.80 2.5263 0.2191 84.6904 36.364

3 1.14 1.20 2.5263 0.1855 71.7064 39.746

4 1.52 1.60 2.5263 0.1540 59.5431 43.128

5 1.9 2.00 2.5263 0.1276 49.3489 46.51

6 2.28 2.40 2.5263 0.1063 41.0865 49.892

7 2.66 2.80 2.5263 0.0891 34.4467 53.274

8 3.04 3.20 2.5263 0.0753 29.1089 56.656

9 3.42 3.60 2.5263 0.0641 24.7999 60.038

10 3.8 4.00 2.5263 0.0551 21.3003 63.42

11 4.18 4.40 2.5263 0.0477 18.4378 66.802

12 4.56 4.80 2.5263 0.0416 16.0786 70.184

13 4.94 5.20 2.5263 0.0365 14.1191 73.566

14 5.32 5.60 2.5263 0.0323 12.4791 76.948

15 5.7 6.00 2.5263 0.0287 11.0963 80.33

16 6.08 6.40 2.5263 0.0257 9.92193 83.712

17 6.46 6.80 2.5263 0.0231 8.91784 87.094

18 6.84 7.20 2.5263 0.0208 8.05379 90.476

19 7.22 7.60 2.5263 0.0189 7.30575 93.858

20 7.6 8.00 2.5263 0.0172 6.65444 97.24

21 7.98 8.40 2.5263 0.0157 6.08433 100.622

22 8.36 8.80 2.5263 0.0144 5.58278 104.004

23 8.74 9.20 2.5263 0.0133 5.13948 107.386

24 9.12 9.60 2.5263 0.0123 4.74591 110.768

25 9.50 10.00 2.5263 0.0114 4.39507 114.150

26 9.88 10.4 2.5263 0.0106 4.08108 117.532

27 10.26 10.8 2.5263 0.0098 3.79904 120.914

28 10.64 11.2 2.5263 0.0092 3.54483 124.296

29 11.02 11.6 2.5263 0.0086 3.31496 127.678

30 11.4 12.0 2.5263 0.0080 3.10645 131.060

13

Bng 6 - Xc nh ng sut gy ln )B(glz

im z (m) z/b Tra gHENMK Tra gFGNMK )B(glz

(KPa) l/b gHENMK l/b gFGNMK

0 0 0.000 1.7708 0.2500 1.0213 0.2500 0.0000

1 0.38 0.158 1.7708 0.2496 1.0213 0.2493 0.1139

2 0.76 0.317 1.7708 0.2467 1.0213 0.2446 0.8127

3 1.14 0.475 1.7708 0.2401 1.0213 0.2342 2.2999

4 1.52 0.633 1.7708 0.2299 1.0213 0.2186 4.3615

5 1.9 0.792 1.7708 0.2170 1.0213 0.1999 6.6001

6 2.28 0.950 1.7708 0.2025 1.0213 0.1801 8.6635

7 2.66 1.108 1.7708 0.1875 1.0213 0.1608 10.3416

8 3.04 1.267 1.7708 0.1727 1.0213 0.1428 11.5597

9 3.42 1.425 1.7708 0.1585 1.0213 0.1266 12.3339

10 3.8 1.583 1.7708 0.1452 1.0213 0.1123 12.7265

11 4.18 1.742 1.7708 0.1329 1.0213 0.0998 12.8154

12 4.56 1.900 1.7708 0.1217 1.0213 0.0889 12.6759

13 4.94 2.058 1.7708 0.1115 1.0213 0.0795 12.3736

14 5.32 2.217 1.7708 0.1022 1.0213 0.0713 11.9616

15 5.7 2.375 1.7708 0.0939 1.0213 0.0642 11.4809

16 6.08 2.533 1.7708 0.0864 1.0213 0.0580 10.9620

17 6.46 2.692 1.7708 0.0796 1.0213 0.0526 10.4273

18 6.84 2.850 1.7708 0.0735 1.0213 0.0479 9.8924

19 7.22 3.008 1.7708 0.0680 1.0213 0.0437 9.3680

20 7.6 3.167 1.7708 0.0630 1.0213 0.0401 8.8612

21 7.98 3.325 1.7708 0.0585 1.0213 0.0368 8.3763

22 8.36 3.483 1.7708 0.0544 1.0213 0.0340 7.9159

23 8.74 3.642 1.7708 0.0507 1.0213 0.0314 7.4811

24 9.12 3.800 1.7708 0.0474 1.0213 0.0291 7.0719

25 9.50 3.958 1.7708 0.0443 1.0213 0.0270 6.6881

26 9.88 4.117 1.7708 0.0415 1.0213 0.0252 6.3286

27 10.26 4.275 1.7708 0.0390 1.0213 0.0235 5.9925

28 10.64 4.433 1.7708 0.0366 1.0213 0.0220 5.6784

29 11.02 4.592 1.7708 0.0345 1.0213 0.0206 5.3850

30 11.4 4.750 1.7708 0.0325 1.0213 0.0193 5.1109

14

Bng 7 - Xc nh ng sut gy ln )C(glz

im z (m) x/b z/b Kz )C(glz (KPa) 0 0 0.7500 0.0000 0.0000 0.0000 1 0.38 0.7500 0.3167 0.1293 19.2046 2 0.76 0.7500 0.6333 0.2507 37.2418 3 1.14 0.7500 0.9500 0.2862 42.5249 4 1.52 0.7500 1.2667 0.2845 42.2727 5 1.9 0.7500 1.5833 0.2686 39.9121 6 2.28 0.7500 1.9000 0.2486 36.9288 7 2.66 0.7500 2.2167 0.2284 33.9374 8 3.04 0.7500 2.5333 0.2098 31.1682 9 3.42 0.7500 2.8500 0.1931 28.6873 10 3.8 0.7500 3.1667 0.1783 26.4939 11 4.18 0.7500 3.4833 0.1653 24.5626 12 4.56 0.7500 3.8000 0.1539 22.8613 13 4.94 0.7500 4.1167 0.1438 21.3585 14 5.32 0.7500 4.4333 0.1348 20.0259 15 5.7 0.7500 4.7500 0.1268 18.8389 16 6.08 0.7500 5.0667 0.1197 17.7770 17 6.46 0.7500 5.3833 0.1132 16.8225 18 6.84 0.7500 5.7000 0.1074 15.9609 19 7.22 0.7500 6.0167 0.1022 15.1799 20 7.6 0.7500 6.3333 0.0974 14.4692 21 7.98 0.7500 6.6500 0.0930 13.8201 22 8.36 0.7500 6.9667 0.0890 13.2251 23 8.74 0.7500 7.2833 0.0853 12.6779 24 9.12 0.7500 7.6000 0.0819 12.1732 25 9.50 0.7500 7.9167 0.0788 11.7062 26 9.88 0.7500 8.2333 0.0759 11.2731 27 10.26 0.7500 8.5500 0.0732 10.8703 28 10.64 0.7500 8.8667 0.0706 10.4948 29 11.02 0.7500 9.1833 0.0683 10.1440 30 11.4 0.7500 9.5000 0.0661 9.8156

15

6.2.4 V biu ng sut bn thn v ng sut gy ln ti im N.

Bng 8 - Xc nh ng sut gy ln glz ti im N

im z (m) )A(glz KPa) )B(glz (KPa) )C(glz (KPa) Nglz (KPa) btz (KPa)0 0 96.6518 0.0000 0.0000 96.6518 29.6 1 0.38 94.3922 0.1139 19.2046 113.7107 32.982 2 0.76 84.6904 0.8127 37.2418 122.7449 36.364 3 1.14 71.7064 2.2999 42.5249 116.5312 39.746 4 1.52 59.5431 4.3615 42.2727 106.1773 43.128 5 1.9 49.3489 6.6001 39.9121 95.8611 46.51 6 2.28 41.0865 8.6635 36.9288 86.6788 49.892 7 2.66 34.4467 10.3416 33.9374 78.7257 53.274 8 3.04 29.1089 11.5597 31.1682 71.8368 56.656 9 3.42 24.7999 12.3339 28.6873 65.8211 60.038

10 3.8 21.3003 12.7265 26.4939 60.5207 63.42 11 4.18 18.4378 12.8154 24.5626 55.8158 66.802 12 4.56 16.0786 12.6759 22.8613 51.6158 70.184 13 4.94 14.1191 12.3736 21.3585 47.8512 73.566 14 5.32 12.4791 11.9616 20.0259 44.4666 76.948 15 5.7 11.0963 11.4809 18.8389 41.4161 80.33 16 6.08 9.92193 10.9620 17.7770 38.6609 83.712 17 6.46 8.91784 10.4273 16.8225 36.1676 87.094 18 6.84 8.05379 9.8924 15.9609 33.9071 90.476 19 7.22 7.30575 9.3680 15.1799 31.8537 93.858 20 7.6 6.65444 8.8612 14.4692 29.9848 97.24 21 7.98 6.08433 8.3763 13.8201 28.2807 100.622 22 8.36 5.58278 7.9159 13.2251 26.7238 104.004 23 8.74 5.13948 7.4811 12.6779 25.2985 107.386 24 9.12 4.74591 7.0719 12.1732 23.9910 110.768 25 9.50 4.39507 6.6881 11.7062 22.7894 114.150 26 9.88 4.08108 6.3286 11.2731 21.6828 117.532 27 10.26 3.79904 5.9925 10.8703 20.6618 120.914 28 10.64 3.54483 5.6784 10.4948 19.7180 124.296 29 11.02 3.31496 5.3850 10.1440 18.8440 127.678 30 11.4 3.10645 5.1109 9.8156 18.0330 131.060

Biu ng sut gy ln v ng sut bn thn ca cc im nm trn trc ng qua N c th hin trn hnh v trang 16.

16

6.2.5 Tnh ton ln ti im N. Gii hn nn tnh n im 25 c:

kPakPa btgl 83,2215,114.2,0.2,07894,22 ==

17

6.3 Tnh ln ti im J. ng sut gy ln ti cc im nm trn trc ng qua J gm: + ng sut gy ln do ti trng ca mng bng.

+ ng sut gy ln do ti trng ca mng trc 4E. + ng sut gy ln do ti trng ca mng trc 3E & 5E. Chia nn di mng thnh nhng phn t c chiu dy hi b/4. Chn hi = 0,25b = 0,25 . 1,2 = 0,30m. 6.3.1 Xc nh ng sut gy ln ti cc im nm trn trc ng qua J do ti trng ca mng bng. ng sut gy ln ti cc im nm trn trc ng qua J do mng bng gy ra:

zglzz

glz KKDi .5667,148)( 0 == =

Trong : zK : tra bng ph thuc x/b v z/b vi b = 1,2m; x = 0.

Cc kt qu tnh ton c lp thnh bng 9 trang 18. 6.3.2 Xc nh ng sut gy ln ti cc im nm trn trc ng qua J do ti trng ca mng trc 4E.

ng sut gy ln ti cc im nm trn trc ng qua J:

)(386,607

).(3035,193.2)(2)( 0

gATJNgDTJM

gATJNgDTJMglzgATJNgDTJM

glz

KK

KKKKEi

=== =

Trong : gDTJMK : tra bng ph thuc l/b v z/b vi b = 0,95m; l = 3,3m. gATJNK : tra bng ph thuc l/b v z/b vi b = 0,9m; l = 0,95m.

Cc kt qu tnh ton c lp thnh bng 10 trang 19. 6.3.3 Xc nh ng sut gy ln ti cc im nm trn trc ng qua J do ti trng ca mng trc 3E v 5E.

Mng trc 3E v 5E i xng nhau qua trc ngang qua J nn ta tnh ng sut gy ln ti cc im nm trn trc ng qua J do ti trng ca mng trc 3E sau nhn vi 2 k n ti trng ca mng trc 5E. ng sut gy ln ti cc im nm trn trc ng qua J do mng trc 3E & 5E:

).(386,607

).(3035,931.2

).(2)( 0

gGSJNgERJNgFSJMgHRJM

gGSJNgERJNgFSJMgHRJM

glzgGSJNgERJNgFSJMgHRJM

glz

KKKK

KKKK

KKKKFi

+=+=

+= =

Trong :

gHRJMK : tra bng ph thuc l/b v z/b vi b = 3,3m; l = 4,25m.

gFSJMK : tra bng ph thuc l/b v z/b vi b = 2,35m; l = 3,30m.

gERJNK : tra bng ph thuc l/b v z/b vi b = 0,9m; l = 4,25m.

gGSJNK : tra bng ph thuc l/b v z/b vi b = 0,9m; l = 2,35m.

18

Cc kt qu tnh ton c lp thnh bng 11, 12, 13 trang 20, 21 v 22. Bng 9 - Xc nh ng sut gy ln )D(glz

im z (m) z/b Kz )D(glz (KPa) btz (KPa) 0 0 0.00 1.0000 148.5667 29.60 1 0.3 0.25 0.9595 142.5469 32.27 2 0.6 0.50 0.8183 121.5736 34.94 3 0.9 0.75 0.6682 99.2661 37.61 4 1.2 1.00 0.5498 81.6842 40.28 5 1.5 1.25 0.4618 68.6024 42.95 6 1.8 1.50 0.3958 58.8055 45.62 7 2.1 1.75 0.3453 51.3052 48.29 8 2.4 2.00 0.3058 45.4244 50.96 9 2.7 2.25 0.2740 40.7106 53.63 10 3 2.50 0.2481 36.8583 56.30 11 3.3 2.75 0.2265 33.6568 58.97 12 3.6 3.00 0.2084 30.9572 61.64 13 3.9 3.25 0.1929 28.6521 64.31 14 4.2 3.50 0.1795 26.6620 66.98 15 4.5 3.75 0.1678 24.9272 69.65 16 4.8 4.00 0.1575 23.4022 72.32 17 5.1 4.25 0.1484 22.0514 74.99 18 5.4 4.50 0.1403 20.8468 77.66 19 5.7 4.75 0.1330 19.7660 80.33 20 6 5.00 0.1265 18.7911 83.00 21 6.3 5.25 0.1205 17.9073 85.67 22 6.6 5.50 0.1151 17.1024 88.34 23 6.9 5.75 0.1102 16.3664 91.01 24 7.2 6.00 0.1056 15.6909 93.68 25 7.5 6.25 0.1014 15.0687 96.35 26 7.5 6.25 0.1014 15.0687 96.35 27 7.8 6.50 0.0976 14.4937 99.02 28 8.1 6.75 0.0940 13.9609 101.69 29 8.4 7.00 0.0906 13.4658 104.36 30 8.7 7.25 0.0875 13.0044 107.03 31 9.3 7.75 0.0819 12.1702 112.37 32 9.6 8.00 0.0794 11.7919 115.04 33 9.9 8.25 0.0770 11.4363 117.71 34 10.2 8.50 0.0747 11.1015 120.38 35 10.5 8.75 0.0726 10.7857 123.05 36 10.8 9.00 0.0706 10.4874 125.72 37 11.1 9.25 0.0687 10.2051 128.39 38 11.4 9.50 0.0669 9.9375 131.06 39 11.7 9.75 0.0652 9.6836 133.73 40 12 10.00 0.0636 9.4423 136.40

19

Bng 10 - Xc nh ng sut gy ln )E(glz im z (m)

Tra gDTJMK Tra gATJNK )E(glz (KPa) z/b l/b gDTJMK z/b l/b gATJNK

0 0 0.00 3.4737 0.2500 0.00 1.0556 0.2500 0.0000 1 0.3 0.32 3.4737 0.2470 0.33 1.0556 0.2444 1.0209 2 0.6 0.63 3.4737 0.2320 0.67 1.0556 0.2176 5.5790 3 0.9 0.95 3.4737 0.2082 1.00 1.0556 0.1784 11.50084 1.2 1.26 3.4737 0.1827 1.33 1.0556 0.1409 16.18645 1.5 1.58 3.4737 0.1595 1.67 1.0556 0.1104 18.98356 1.8 1.89 3.4737 0.1395 2.00 1.0556 0.0872 20.21657 2.1 2.21 3.4737 0.1225 2.33 1.0556 0.0698 20.38098 2.4 2.53 3.4737 0.1082 2.67 1.0556 0.0567 19.88239 2.7 2.84 3.4737 0.0960 3.00 1.0556 0.0468 19.003310 3 3.16 3.4737 0.0855 3.33 1.0556 0.0391 17.928911 3.3 3.47 3.4737 0.0765 3.67 1.0556 0.0331 16.775912 3.6 3.79 3.4737 0.0688 4.00 1.0556 0.0284 15.615713 3.9 4.11 3.4737 0.0620 4.33 1.0556 0.0245 14.490714 4.2 4.42 3.4737 0.0561 4.67 1.0556 0.0214 13.424615 4.5 4.74 3.4737 0.0510 5.00 1.0556 0.0188 12.428816 4.8 5.05 3.4737 0.0464 5.33 1.0556 0.0167 11.507717 5.1 5.37 3.4737 0.0425 5.67 1.0556 0.0149 10.661118 5.4 5.68 3.4737 0.0389 6.00 1.0556 0.0133 9.8859 19 5.7 6.00 3.4737 0.0358 6.33 1.0556 0.0120 9.1779 20 6 6.32 3.4737 0.0330 6.67 1.0556 0.0109 8.5320 21 6.3 6.63 3.4737 0.0305 7.00 1.0556 0.0099 7.9432 22 6.6 6.95 3.4737 0.0282 7.33 1.0556 0.0091 7.4063 23 6.9 7.26 3.4737 0.0262 7.67 1.0556 0.0083 6.9164 24 7.2 7.58 3.4737 0.0244 8.00 1.0556 0.0077 6.4690 25 7.5 7.89 3.4737 0.0228 8.33 1.0556 0.0071 6.0600 26 7.8 8.21 3.4737 0.0213 8.67 1.0556 0.0066 5.6857 27 8.1 8.53 3.4737 0.0199 9.00 1.0556 0.0061 5.3425 28 8.4 8.84 3.4737 0.0187 9.33 1.0556 0.0057 5.0274 29 8.7 9.16 3.4737 0.0175 9.67 1.0556 0.0053 4.7378 30 9 9.47 3.4737 0.0165 10.00 1.0556 0.0050 4.4711 31 9.3 9.79 3.4737 0.0156 10.33 1.0556 0.0046 4.2251 32 9.6 10.11 3.4737 0.0147 10.67 1.0556 0.0044 3.9979 33 9.9 10.42 3.4737 0.0139 11.00 1.0556 0.0041 3.7877 34 10.2 10.74 3.4737 0.0132 11.33 1.0556 0.0039 3.5930 35 10.5 11.05 3.4737 0.0125 11.67 1.0556 0.0037 3.4123 36 10.8 11.37 3.4737 0.0118 12.00 1.0556 0.0035 3.2443 37 11.1 11.68 3.4737 0.0113 12.33 1.0556 0.0033 3.0881 38 11.4 12.00 3.4737 0.0107 12.67 1.0556 0.0031 2.9425 39 11.7 12.32 3.4737 0.0102 13.00 1.0556 0.0030 2.8066 40 12 12.63 3.4737 0.0097 13.33 1.0556 0.0028 2.6796

20

Bng 11 - Xc nh gHRJMK & gFSJMK

im z (m) Tra gHRJMK Tra gFSJMK

z/b l/b gHRJMK z/b l/b gFSJMK 0 0 0.000 1.2879 0.2500 0.000 1.4042 0.2500 1 0.3 0.091 1.2879 0.2499 0.128 1.4042 0.2497 2 0.6 0.182 1.2879 0.2492 0.255 1.4042 0.2480 3 0.9 0.273 1.2879 0.2474 0.383 1.4042 0.2437 4 1.2 0.364 1.2879 0.2442 0.511 1.4042 0.2366 5 1.5 0.455 1.2879 0.2394 0.638 1.4042 0.2270 6 1.8 0.545 1.2879 0.2332 0.766 1.4042 0.2154 7 2.1 0.636 1.2879 0.2257 0.894 1.4042 0.2026 8 2.4 0.727 1.2879 0.2171 1.021 1.4042 0.1893 9 2.7 0.818 1.2879 0.2079 1.149 1.4042 0.1759 10 3 0.909 1.2879 0.1981 1.277 1.4042 0.1629 11 3.3 1.000 1.2879 0.1882 1.404 1.4042 0.1505 12 3.6 1.091 1.2879 0.1783 1.532 1.4042 0.1389 13 3.9 1.182 1.2879 0.1685 1.660 1.4042 0.1282 14 4.2 1.273 1.2879 0.1590 1.787 1.4042 0.1183 15 4.5 1.364 1.2879 0.1499 1.915 1.4042 0.1092 16 4.8 1.455 1.2879 0.1412 2.043 1.4042 0.1009 17 5.1 1.545 1.2879 0.1330 2.170 1.4042 0.0933 18 5.4 1.636 1.2879 0.1252 2.298 1.4042 0.0865 19 5.7 1.727 1.2879 0.1179 2.426 1.4042 0.0802 20 6 1.818 1.2879 0.1111 2.553 1.4042 0.0746 21 6.3 1.909 1.2879 0.1047 2.681 1.4042 0.0694 22 6.6 2.000 1.2879 0.0988 2.809 1.4042 0.0647 23 6.9 2.091 1.2879 0.0932 2.936 1.4042 0.0604 24 7.2 2.182 1.2879 0.0880 3.064 1.4042 0.0565 25 7.5 2.273 1.2879 0.0832 3.191 1.4042 0.0530 26 7.8 2.364 1.2879 0.0787 3.319 1.4042 0.0497 27 8.1 2.455 1.2879 0.0746 3.447 1.4042 0.0467 28 8.4 2.545 1.2879 0.0707 3.574 1.4042 0.0440 29 8.7 2.636 1.2879 0.0671 3.702 1.4042 0.0414 30 9 2.727 1.2879 0.0637 3.830 1.4042 0.0391 31 9.3 2.818 1.2879 0.0605 3.957 1.4042 0.0370 32 9.6 2.909 1.2879 0.0576 4.085 1.4042 0.0350 33 9.9 3.000 1.2879 0.0548 4.213 1.4042 0.0332 34 10.2 3.091 1.2879 0.0522 4.340 1.4042 0.0315 35 10.5 3.182 1.2879 0.0498 4.468 1.4042 0.0299 36 10.8 3.273 1.2879 0.0476 4.596 1.4042 0.0284 37 11.1 3.364 1.2879 0.0454 4.723 1.4042 0.0271 38 11.4 3.455 1.2879 0.0435 4.851 1.4042 0.0258 39 11.7 3.545 1.2879 0.0416 4.979 1.4042 0.0246 40 12 3.636 1.2879 0.0398 5.106 1.4042 0.0235

21

Bng 12 - Xc nh gERJNK & gGSJNK

im z (m) Tra gERJNK Tra gGSJNK

z/b l/b gERJNK z/b l/b gGSJNK 0 0 0.000 4.7222 0.2500 0.000 2.6111 0.2500 1 0.3 0.333 4.7222 0.2465 0.333 2.6111 0.2465 2 0.6 0.667 4.7222 0.2298 0.667 2.6111 0.2292 3 0.9 1.000 4.7222 0.2044 1.000 2.6111 0.2027 4 1.2 1.333 4.7222 0.1783 1.333 2.6111 0.1749 5 1.5 1.667 4.7222 0.1553 1.667 2.6111 0.1499 6 1.8 2.000 4.7222 0.1360 2.000 2.6111 0.1285 7 2.1 2.333 4.7222 0.1200 2.333 2.6111 0.1105 8 2.4 2.667 4.7222 0.1066 2.667 2.6111 0.0955 9 2.7 3.000 4.7222 0.0954 3.000 2.6111 0.0829 10 3 3.333 4.7222 0.0858 3.333 2.6111 0.0724 11 3.3 3.667 4.7222 0.0775 3.667 2.6111 0.0636 12 3.6 4.000 4.7222 0.0704 4.000 2.6111 0.0561 13 3.9 4.333 4.7222 0.0641 4.333 2.6111 0.0498 14 4.2 4.667 4.7222 0.0586 4.667 2.6111 0.0444 15 4.5 5.000 4.7222 0.0537 5.000 2.6111 0.0398 16 4.8 5.333 4.7222 0.0494 5.333 2.6111 0.0358 17 5.1 5.667 4.7222 0.0455 5.667 2.6111 0.0324 18 5.4 6.000 4.7222 0.0421 6.000 2.6111 0.0294 19 5.7 6.333 4.7222 0.0390 6.333 2.6111 0.0268 20 6 6.667 4.7222 0.0362 6.667 2.6111 0.0245 21 6.3 7.000 4.7222 0.0337 7.000 2.6111 0.0225 22 6.6 7.333 4.7222 0.0314 7.333 2.6111 0.0207 23 6.9 7.667 4.7222 0.0293 7.667 2.6111 0.0191 24 7.2 8.000 4.7222 0.0274 8.000 2.6111 0.0177 25 7.5 8.333 4.7222 0.0257 8.333 2.6111 0.0164 26 7.8 8.667 4.7222 0.0241 8.667 2.6111 0.0153 27 8.1 9.000 4.7222 0.0227 9.000 2.6111 0.0143 28 8.4 9.333 4.7222 0.0213 9.333 2.6111 0.0133 29 8.7 9.667 4.7222 0.0201 9.667 2.6111 0.0125 30 9 10.000 4.7222 0.0190 10.000 2.6111 0.0117 31 9.3 10.333 4.7222 0.0180 10.333 2.6111 0.0110 32 9.6 10.667 4.7222 0.0170 10.667 2.6111 0.0104 33 9.9 11.000 4.7222 0.0161 11.000 2.6111 0.0098 34 10.2 11.333 4.7222 0.0153 11.333 2.6111 0.0092 35 10.5 11.667 4.7222 0.0145 11.667 2.6111 0.0087 36 10.8 12.000 4.7222 0.0138 12.000 2.6111 0.0083 37 11.1 12.333 4.7222 0.0132 12.333 2.6111 0.0079 38 11.4 12.667 4.7222 0.0126 12.667 2.6111 0.0075 39 11.7 13.000 4.7222 0.0120 13.000 2.6111 0.0071 40 12 13.333 4.7222 0.0115 13.333 2.6111 0.0068

22

Bng 13 - Xc nh ng sut gy ln )F(glz im z (m) gHRJMK gFSJMK gERJNK gGSJNK )F(glz (kPa)

0 0 0.2500 0.2500 0.2500 0.2500 0.0000 1 0.3 0.2499 0.2497 0.2465 0.2465 0.0773 2 0.6 0.2492 0.2480 0.2298 0.2292 0.2320 3 0.9 0.2474 0.2437 0.2044 0.2027 0.7732 4 1.2 0.2442 0.2366 0.1783 0.1749 1.6237 5 1.5 0.2394 0.2270 0.1553 0.1499 2.7062 6 1.8 0.2332 0.2154 0.1360 0.1285 3.9821 7 2.1 0.2257 0.2026 0.1200 0.1105 5.2579 8 2.4 0.2171 0.1893 0.1066 0.0955 6.4563 9 2.7 0.2079 0.1759 0.0954 0.0829 7.5388 10 3 0.1981 0.1629 0.0858 0.0724 8.4280 11 3.3 0.1882 0.1505 0.0775 0.0636 9.2012 12 3.6 0.1783 0.1389 0.0704 0.0561 9.7038 13 3.9 0.1685 0.1282 0.0641 0.0498 10.0518 14 4.2 0.1590 0.1183 0.0586 0.0444 10.2451 15 4.5 0.1499 0.1092 0.0537 0.0398 10.3611 16 4.8 0.1412 0.1009 0.0494 0.0358 10.3224 17 5.1 0.1330 0.0933 0.0455 0.0324 10.2837 18 5.4 0.1252 0.0865 0.0421 0.0294 10.0518 19 5.7 0.1179 0.0802 0.0390 0.0268 9.8585 20 6 0.1111 0.0746 0.0362 0.0245 9.5879 21 6.3 0.1047 0.0694 0.0337 0.0225 9.3172 22 6.6 0.0988 0.0647 0.0314 0.0207 9.0466 23 6.9 0.0932 0.0604 0.0293 0.0191 8.7373 24 7.2 0.0880 0.0565 0.0274 0.0177 8.4280 25 7.5 0.0832 0.0530 0.0257 0.0164 8.0801 26 7.8 0.0787 0.0497 0.0241 0.0153 7.8095 27 8.1 0.0746 0.0467 0.0227 0.0143 7.5388 28 8.4 0.0707 0.0440 0.0213 0.0133 7.2296 29 8.7 0.0671 0.0414 0.0201 0.0125 6.9976 30 9 0.0637 0.0391 0.0190 0.0117 6.6883 31 9.3 0.0605 0.0370 0.0180 0.0110 6.3790 32 9.6 0.0576 0.0350 0.0170 0.0104 6.1857 33 9.9 0.0548 0.0332 0.0161 0.0098 5.9151 34 10.2 0.0522 0.0315 0.0153 0.0092 5.6445 35 10.5 0.0498 0.0299 0.0145 0.0087 5.4512 36 10.8 0.0476 0.0284 0.0138 0.0083 5.2965 37 11.1 0.0454 0.0271 0.0132 0.0079 5.0259 38 11.4 0.0435 0.0258 0.0126 0.0075 4.8712 39 11.7 0.0416 0.0246 0.0120 0.0071 4.6779 40 12 0.0398 0.0235 0.0115 0.0068 4.4846

23

6.3.4 V biu ng sut bn thn v ng sut gy ln ti im J. Bng 14 - Xc nh ng sut gy ln glz ti im J

im z (m) )D(glz (KPa) )E(glz KPa) )F(glz (kPa) )J(glz (KPa) btz (KPa)0 0 148.5667 0.0000 0.0000 148.5667 29.60 1 0.3 142.5469 1.0209 0.0773 143.6451 32.27 2 0.6 121.5736 5.5790 0.2320 127.3846 34.94 3 0.9 99.2661 11.5008 0.7732 111.5401 37.61 4 1.2 81.6842 16.1864 1.6237 99.4943 40.28 5 1.5 68.6024 18.9835 2.7062 90.2921 42.95 6 1.8 58.8055 20.2165 3.9821 83.0041 45.62 7 2.1 51.3052 20.3809 5.2579 76.944 48.29 8 2.4 45.4244 19.8823 6.4563 71.763 50.96 9 2.7 40.7106 19.0033 7.5388 67.2527 53.63 10 3 36.8583 17.9289 8.4280 63.2152 56.30 11 3.3 33.6568 16.7759 9.2012 59.6339 58.97 12 3.6 30.9572 15.6157 9.7038 56.2767 61.64 13 3.9 28.6521 14.4907 10.0518 53.1946 64.31 14 4.2 26.6620 13.4246 10.2451 50.3317 66.98 15 4.5 24.9272 12.4288 10.3611 47.7171 69.65 16 4.8 23.4022 11.5077 10.3224 45.2323 72.32 17 5.1 22.0514 10.6611 10.2837 42.9962 74.99 18 5.4 20.8468 9.8859 10.0518 40.7845 77.66 19 5.7 19.7660 9.1779 9.8585 38.8024 80.33 20 6 18.7911 8.5320 9.5879 36.911 83.00 21 6.3 17.9073 7.9432 9.3172 35.1677 85.67 22 6.6 17.1024 7.4063 9.0466 33.5553 88.34 23 6.9 16.3664 6.9164 8.7373 32.0201 91.01 24 7.2 15.6909 6.4690 8.4280 30.5879 93.68 25 7.5 15.0687 6.0600 8.0801 29.2088 96.35 26 7.5 15.0687 5.6857 7.8095 28.5639 96.35 27 7.8 14.4937 5.3425 7.5388 27.375 99.02 28 8.1 13.9609 5.0274 7.2296 26.2179 101.69 29 8.4 13.4658 4.7378 6.9976 25.2012 104.36 30 8.7 13.0044 4.4711 6.6883 24.1638 107.03 31 9.3 12.1702 4.2251 6.3790 22.7743 112.37 32 9.6 11.7919 3.9979 6.1857 21.9755 115.04 33 9.9 11.4363 3.7877 5.9151 21.1391 117.71 34 10.2 11.1015 3.5930 5.6445 20.339 120.38 35 10.5 10.7857 3.4123 5.4512 19.6492 123.05 36 10.8 10.4874 3.2443 5.2965 19.0282 125.72 37 11.1 10.2051 3.0881 5.0259 18.3191 128.39 38 11.4 9.9375 2.9425 4.8712 17.7512 131.06 39 11.7 9.6836 2.8066 4.6779 17.1681 133.73 40 12 9.4423 2.6796 4.4846 16.6065 136.40

24

Biu ng sut gy ln v ng sut bn thn ca cc im nm trn trc ng qua J c th hin trn hnh v trang 24.

6.3.5 Tnh ton ln ti im J. Gii hn nn tnh n im 32 c:

kPakPa btgl 008,23115,04.2,0.2,021,9755 ==

25

ln c xc nh theo cng thc sau:

cmm

hE

Sn

ii

glzi

406,40,044062

21,975522,7743...143,64512

148,566730,0.9840

8,0

10

==

++++== =

7. Kim tra nn v sc chu ti.

p lc gii hn ca nn : cccqqqgh i.S..c.Ni.S.h'.Ni.S.2b..N ++=

= 180 tra bng c: N = 4,07; Nq = 5,26; Nc = 13,10; =0 i =1=iq =ic. 7.1 Mng n. Mng ch nht:

S = 1- 0,4b/l = 1 - 0,4.1,9/2,4 = 0,6833 Sc = Sq = 1 + 0,3b/l = 1 + 0,3.1,9/2,4 = 1,2375 el = 0,117m l = l - 2el = 2,4 2.0,117 = 2,166m; bb = =1,9m

kPa

gh

556,6237

1.2375,1.21.10,131.2375,1.6,1.5,18.26,51.6833,0.29,1.90,8.07,4

=++=

p lc cho php:

kPaFSgh

a 311,2782556,6237 ===

a > 1,15 . tb = 1,15.222,9035 = 256,339 kN Ti trng cho php:

Na = b.l.a = 278,311.2,166.1,9 = 1145,361kN Na = 1145,361kN >

ttN0 = 1,15. 850 = 977,5kN Vy nn mng n m bo iu kin n nh v sc chu ti. 7.2 Mng bng. Mng bng:

S = Sc = Sq = 1; eb = 0,0941m b = b - 2eb = 1,2 2.0,0941 = 1,0118m; l = l = 1m

kPagh 449,12121.1.21.10,131.1.6,1.5,18.26,51.1.20118,1.90,8.07,4 =++=

p lc cho php: kPaFSgh

a 56,2242449,1212 ===

a > 1,15 . tb = 1,15 . 148,5667 = 170,8517 kN Ti trng cho php:

Na = b.l.a = 224,56 . 1 . 1,0118 = 227,21kN Na = 227,21kN >

ttbN0 = 1,15. 170 = 195,5kN

Vy nn mng bng m bo iu kin n nh v sc chu ti.