N THIT K NN MT NG

SVTH: NGUYN QUC HNG

CHNG I: THIT K KT CU NN - O NGI. C s thit k kt cu nn- o ng 1. Quy trnh tnh ton ti trng tnh ton. Kt cu o ng c thit k theo quy trnh thit k o ng mm 22TCN 211-06. Cc c trng ti trng trc tnh ton theo tiu chun sau: + Ti trng trc tnh ton tiu chun P = 100kN. + p lc tnh ton ln mt ng p = 0.6Mpa. + ng knh vt bnh xe D = 33cm. 2. Xc nh lu lng trc xe tnh ton. S trc xe tnh ton Ntt l tng s trc xe c quy i v trc xe tnh ton tiu chun s thng qua mt ct ngang ca on ng thit k trong 1 ngy m trn ln xe chu ng ln nht vo thi k bt li nht cui thi hn thit k, ty thuc loi tng mt d kin la chn cho kt cu o ng. Xc nh Ntt theo cng thc: Ntt = Ntk.f1 (trc/ln.ngy m) Trong : f1: h s phn phi trc xe tnh ton trn mi ln xe, phn xe chy c 2 ln xe khng c di phn cch nn chn f1 = 0.55. Ntk: l tng s trc xe quy i t k loi xe khc nhau v trc xe tnh ton trong mt ngy m trn c 2 chiu xe chy nm cui thi hn thit k.

Trong : Ni: s ln tc dng ca loi ti trng trc i c trng lng trc pi cn c quy i v ti trng trc tnh ton Ptt (trc tiu chun). Trong tnh ton quy i thng ly ni bng s ln ca mi loi xe i s thng qua mt ct ngang in hnh ca on ng thit k trong mt ngy m cho c 2 chiu xe chy. C1: l h s trc c (xt n s trc trong 1 cm trc c cng ti trng l Pi). C1 ph thuc vo khong cch gia cc trc (L) GVHD: THS V VN NHN TRANG 1

N THIT K NN MT NG

SVTH: NGUYN QUC HNG

Nu L >= 3m th C1= m(s trc). Nu L < 3m th C1 = 1+1,2.(m-1). C2: h s xt n tc dng ca s bnh xe trong 1 cm bnh, vi cc cm ch c 1 bnh th ly C2= 6.4, i vi cc cm bnh gm 2 bnh th C2= 1, cm bnh c 4 bnh th C2= 0.38. Ptt: ti trng trc tnh ton tiu chun, Ptt = 100kN. Pi : ti trng trc th i.

GVHD: THS V VN NHN

TRANG 2

N THIT K NN MT NG

SVTH: NGUYN QUC HNG

Ta c lu lng xe nm thit k 2012 l 370 xe/ng. Thnh phn dng xe nm thit k 2012 Loi xe Xe con Xe ti nh Xe ti trung Xe ti nng T l (%) 20 26 31 23 Lu lng (xe/ng) 74 96 115 85

Quy lut tng trng xe : q = 9%/nm D kin chn chn vt liu cp cao th yu A2 vi vt liu l lng nha. Lu lng xe tnh ton 1 s nm i din Ntt xe con ti nh ti trung ti nng Xe/ng.d 676 135 175 210 155 737 876 1349 147 175 270 192 228 351 228 272 418 170 201 310

Nm 7 8 10 15

S trc xe quy i v s trc tnh ton tiu chun 100kN nm th 7 Loi Xe Pi(kN) Ptc C1 C2 Ni Ntk 38 100 1 6.4 175 16 Xe ti Trc trc Trc sau 56 100 1 1 nh 175 14 43 100 1 6.4 210 33 Xe ti Trc trc Trc sau 64 100 2 1 trung 210 59 Trc trc 39 100 1 6.4 155 16 Xe ti Trc gia 70 100 2 1 155 65 nng Trc sau 79 100 2.2 1 155 121 Ntk= 322 trc 100KN Tng s trc xe quy i nm th 7 - S trc xe quy i v s trc tnh ton tiu chun 100kN ca cc nm. Nm th 7 8 10 15 Ntk (trc 100KN) 322 353 418 643 Ntt (trc/ln.ngy m) 177 194 230 354

GVHD: THS V VN NHN

TRANG 3

N THIT K NN MT NG

SVTH: NGUYN QUC HNG

-

S trc xe tnh ton tiu chun trn l gia c:

S trc xe tnh ton Ntt thit k o l gia c trong trng hp gia phn xe chy chnh v l khng c di phn cch bn c ly bng 35-50% s trc xe tnh ton ca ln xe c gii lin k tu thuc vic b tr phn xe chy chnh. Trng hp phn xe chy ch c 2 ln xe tr xung th nn ly tr s ln trong phm vi quy nh nu trn, cn trng hp phn xe chy c 4 ln tr ln v c di phn cch gia th ly tr s nh. Vy chn 50% s trc xe tnh ton: Nm th Ntt 7 88.5 8 97 10 115 15 177

- Tnh s trc xe tiu chun tch ly trong thi hn thit k Ne: Trng hp bit s trc d bo nm u thit k Ntt (truc/ng.ln) th tnh Ne theo cng thc:

Trong : Ntt: s trc xe d bo nm cui thi hn thit k trn mt ln xe. Ne: s trc xe tiu chun tch ly cui thi hn thit k. S trc xe tiu chun tch ly trong thi hn thit k Ne Nm th Ne 7 567526 8 618879 10 733723 15 1129295

Tng hp cc kt qu tnh lu lng trc xe tnh ton Nm th 7 8 10 15 k lun: Ntk 322 353 418 643 Ntt 177 194 230 354 Ne 567526 618879 733723 1129295

GVHD: THS V VN NHN

TRANG 4

N THIT K NN MT NG

SVTH: NGUYN QUC HNG

3. Xc nh modun n hi yu cu. c xc nh theo cc iu kin. - Cp thit k ca ng : Cp IV vn tc thit k Vtk = 40 km/h. - Loi mt ng : A1 hoc A2 Tra bng 3-5 ca 22TCN 211-06 tr Eyc tng ng Xc nh moun n hi yu cu theo lu lng trc xe tnh ton (Eycll). Xc nh moun n hi yu cu ti thiu theo chc nng (Eycmin). Nm Loi tng Eycmi Ntt Eycll Eyc(chn) thit k mt n 7 177 132.01 100 132.01 Phn 8 194 Cp cao A2 134.22 100 134.22 xe 10 230 136.8 100 136.8 chy 15 354 Cp cao A1 169.24 130 169.24 7 88.5 119.24 80 119.24 Phn 8 97 Cp cao A2 121.28 80 121.28 l gia 10 115 123.95 80 123.95 c 15 177 Cp cao A1 157.01 110 157.01 Bng xc nh tr s modun n hi yu cu ti cc nm tnh ton Vi tr

GVHD: THS V VN NHN

TRANG 5

N THIT K NN MT NG

SVTH: NGUYN QUC HNG

4. Xc nh loi tng mt - Nm 2010, tc tng trng kinh t ca Huyn t 11%, c cu kinh t nng lm thu sn 41%; cng nghip xy dng 26%, dch v 33%, thu nhp bnh qun u ngi t 9,8 triu ng/ngi/nm. Tng sn lng lng thc 55.0087 tn, t 85,4% k hoch, tng thu ngn sch nh nc trn a bn: 53 t ng t 151% KH, bng 100% so vi cng k. Cc nh hng pht trin trong tng lai : Cc lnh vc c u tin pht trin: nng lm thy sn

Chc nng v ngha phc v ca tuyn ng : ng ni cc im lp hng - vn tc thit k V = 40km/h - Theo tiu chun 22TCN211-06 T nhng iu kin trn ta chn loi tng mt cao cp th yu A2. II. THIT K CU TO 1. Quan im thit k cu to. Cc nguyn tc thit k cu to theo TCN 211-06: + Phi tun theo nguyn tc thit k tng th nn o ng, ng thi, cn phi s dng cc bin php tng hp khc nhau hn ch tc dng ca m v nhit n cng v bn ca mi tng, lp trong kt cu o ng v c bit l bin php hn ch cc hin tng ph hoi b mt i vi lp mt trn cng do xe chy gy ra. + Chn v b tr cc tng, lp vt liu ph hp vi chc nng ca mi tng lp v bo m c kt cu cng v hn ch ti a cc trng hp ph hoi ca xe, ng thi ph hp vi kh nng cung ng vt liu, kh nng thi cng v kh nng khai thc duy tu, bo dng sau ny. S dng ti a cc vt liu v ph thi cng nghip ti ch v vn dng cc kinh nghim xy dng ti a phng. + xut t 2-3 phng n m bo yu cu bo v mi trng, an ton giao thng, bo v sc khe, an ton cho ngi thi cng. + Xt n phng n phn k u t trong thit k cu to kt cu o ng. + i vi cc on ng c tng mt l loi cp cao A1 nhng qua vng t yu c kh nng pht sinh ln ln v ko di th c th thit k theo nguyn tc phn k xy dng trn c s m bo tng mt cp cao A1 trn khng b h hi do ln. Lc thit k vn phi da vo lng giao thng cui thi hn thit k thit k kt cu v b dy nhng khi thi cng c th gim bt b dy tng mt tng ng vi thi gian phn k, i sau khi nn GVHD: THS V VN NHN TRANG 6

N THIT K NN MT NG

SVTH: NGUYN QUC HNG

ng i vo n nh mi ri tip lp mt b tng nha cp cao A1 hoc cc lp to phng, to nhm trn cng. Yu cu thit k tng mt. + i vi tng mt cp cao A2: Vi tng mt ny lp trn phi l lp hao mn, to nhm, to phng (thng s dng lp lng nha ri trn lp mt bng b tng nha h, dm en, b tng nha ngui, lp thm nhp nha). Pha di gm 1 lp vt liu c th l b tng nha loi II, thm nhp nha hoc lng nha c b dy theo 22 TCN 211-06. - Yu cu thit k tng mng: + Nn gm nhiu lp nhng cng khng nn qu nhiu trnh phc tp cho thi cng v ko di thi gian khai trin dy chuyn thi cng. Cng v kh nng chng bin dng ca lp trn phi ln hn cc lp di, t s moddun n hi gia lp trn v lp di nn < 3ln, gia lp trn v t nn nn trong phm vi 2,5-10 ln. + ht vt liu lp mng trn phi nh hn c ht vt liu ca lp mng pha di. + Chn loi tng mng cn da vo bng 2-3 theo tiu chun 22 TCN 21106.

GVHD: THS V VN NHN

TRANG 7

N THIT K NN MT NG

SVTH: NGUYN QUC HNG

T cc quan im tng qut ni trn, kin ngh s dng mt s vt liu sau cho kt cu nn mt ng. Loi tng Loi vt liu dy kt cu Ti thiu Ti a - BTN cht ht trung loi II, Dmax= 20mm, dm 4,0 6,0 - Lp thm nhp nha, ri dm 10-20mm - Lp lng nha 2 lp, 10-16mm ln th nht, 4,5 6,0 Tng mt 5-10 cho ln th 2 2,0 2,5 - Cp phi dm nghin loi I. - Cp phi dm nghin loi II. - Cp phi thin nhin loi B - b tng nha rng, hn hp nha trn ngui, lp thm nhp nha. - Cp phi gia c xi mng, ct gia c xi mng. Rn28= 2Mpa, Dmax=25mm - t, ct, ph liu cng nghip gia c cht lin kt v c, hu c, tng hp. - Cp phi thin nhin. - dm nc. - t, ct, ph liu cng nghip gia c cht lin kt v c, hu c, tng hp. 15 24 15 24 15 30

Mng trn

15 18 15 18

Mng di

15 30 15 18 15 18

2. xut cc phng n cu to kt cu nn-o ng. a. Phn tch u nhc im cc vt liu c th s dng B tng nha: + u im: cng ngh ph bin, giao thng m thun, gi thnh r. + Nhc im: nhit thp BTN tim cn n nhit ha cng lm cho kt cu tr nn dn, d v khi gp tc ng ln t ti trng ng, nhit cao BTN c xu hng ha mm, khi gp ti trng trng phc, lc hm, ti trng ln d gy bong trc, gy v, n ng. Lp thm nhp nha c nhc im c bn l nha bc cc vin khng u, tn nhiu nha, nn thng dng khi khng iu kin thi cng lp mt nha, cng c th dng lm lp mt ng trong giai on u ca phn k u t xy dng. GVHD: THS V VN NHN TRANG 8

N THIT K NN MT NG

SVTH: NGUYN QUC HNG

Lp lng nha c u im: to dnh bm tt, bo v khng nc thm xung mt ng, nng cao bng phng, nhm v chng mi mn. Cp phi dm c th xem nh l 1 loi t cc tt. C nhc im l d b phn tng khi vn chuyn v thi cng. b. Cc phng n KCA Phng n Loi tng mt Lp 1 2 3 4 1 2 3 4 1 2 3 4 Vt liu B tng nha cht loi II, ht trung Cp phi dm loi I Cp phi dm loi II t nn k98 Lp thm nhp nha Cp phi dm loi I Cp phi dm loi II t nn k98 B tng nha cht loi II, ht trung Cp phi dm loi II Cp phi thin nhin t nn k98 B dy tng mt 6

1

Cp cao A2

6

2 Cp cao A2

6

3

Cp cao A2

GVHD: THS V VN NHN

TRANG 9

N THIT K NN MT NG

SVTH: NGUYN QUC HNG

Tnh ton cng kt cu nn o ng. a.Xc nh c trng tnh ton ca nn ng v cc lp vt liu mt ng: b.Xc nh chiu dy mng. Vt liu v cc ch tiu c bn BTN cht ht trung loi II, Dmax= 15mm Cp phi dm loi I, Dmax= 25mm Cp phi dm loi II, Dmax= 37,5mm Lp thm nhp nha, ri dm 10 -20mm Cp phi thin nhin t nn K98, st a = 0,65 (c ln si sn) - Phng n 1. Mun n hi E(Mpa) Vng Trt 245 300 250 280 200 53 53 53 0.04 0.028 40 21 175 300 250 Un 1260 300 250 Rku (Mpa) 1.8 C (Mpa) (o)

Gi thit chiu dy lp tng mt: h1 = 6cm Modul n hi ca nm thit k l 136.8 Mpa. tin cy R = 95% => Kdv=1.17.

GVHD: THS V VN NHN

TRANG 10

N THIT K NN MT NG

SVTH: NGUYN QUC HNG

8x EycE. Kdv =136.2451.17 = 0.65 1 H 0.06 = = 0.18 D 0.33

tra ton kogan =>

Ech2 = 0.63 E1

Ech2 = 0.63 x 245 = 154.4 (Mpa) Gi thit h2=12cm ( theo iu kin thi cng )

Ech 2 =154.4 = 0.51 E 2 300 H = 0..12 = 0.36 D 0 33 Ech3 = 135 = 0.54 E 3 250 53 E 0 = 250 = 0.21 E3H3 = 40 cm

Tra ton kogan =>

Ech3 = 0.45 E2

Ech3 = 0.45 x 300 = 135 (Mpa) Ta c :

Tra ton kogan =>

H = 1.22 D

B DY (cm) GII PHP 1 GII PHP 2 GII PHP 3

Bng kt qu phng n 1. PHNG N 1 H1 H2 6 12 6 13 6 15

H3 40 36 28

GVHD: THS V VN NHN

TRANG 11

N THIT K NN MT NG

SVTH: NGUYN QUC HNG

-

Phng n 2.

Lm tng t nh phng n 1 ta c: Bng kt qu phng n 2. PHNG N 2 B DY (cm) H1 H2 GII PHP 1 6 12 GII PHP 2 6 13 GII PHP 3 5 15 - Phng n 3

H3 26 16 18

GVHD: THS V VN NHN

TRANG 12