tcn 272-05 full

B GIAO THNG VN TI

TIU CHUN K THUT

CNG TRNH GIAO THNG TP VIII

TIU CHUN THIT K CU

SPECIFICATION FOR BRIDGE DESIGN 22TCN 272-05

NH XUT BN GIAO THNG VN TI H NI - 2005

Tiu chun thit k cu I

Mc lc

Phn 1. gii thiu chung 1

1.1. phm vi ............................................................................................................................ 1

1.2. cc nh ngha............................................................................................................ 2

1.3. trit l thit k ........................................................................................................ 3

Phn 2. thit k tng th v c im v tr cu... 7

2.1. phm vi cp.............................................................................................................. 7

2.2. cc nh ngha............................................................................................................ 7

2.3. cc c trng v tr ............................................................................................... 9

2.4. kho st mng............................................................................................................ 14

2.5. mc ch thit k ..................................................................................................... 14

2.6. thu vn v thu lc............................................................................................. 20

Phn 3. ti trng v h s ti trng. 27

3.1. phm vi ............................................................................................................................ 27

3.2. cc nh ngha ............................................................................................................ 27

3.3. k hiu............................................................................................................................. 29

3.4. cc h s v t hp ti trng ............................................................................ 32

3.5. ti trng thng xuyn ....................................................................................... 36

3.6. hot ti .......................................................................................................................... 36

3.7. ti trng nc: WA................................................................................................... 44

3.8. ti trng gi: WL v WS ........................................................................................ 45

3.9. v ti trng bng tuyt khng bin son ................................................. 49

3.10. hiu ng ng t: EQ ........................................................................................... 49

3.11. p lc t: EH, ES, LS, v DD ................................................................................ 57

3.12. ng lc do bin dng cng bc: TU, TG, SH, CR, SE ................................. 69

3.13. lc ma st: FR ............................................................................................................ 72

3.14. va ca tu thuyn: CV.......................................................................................... 72

Tiu chun thit k cu II

Phn 4. phn tch v nh gi kt cu.. 79

4.1. phm vi ............................................................................................................................ 79

4.2. nh ngha ..................................................................................................................... 79

4.3. k hiu............................................................................................................................. 83

4.4. cc phng php phn tch kt cu c chp nhn ............................. 85

4.5. m hnh ton hc...................................................................................................... 86

4.6. phn tch tnh hc.................................................................................................... 90

4.7. phn tch ng lc hc ......................................................................................... 122

4.8. phn tch theo m hnh vt l........................................................................... 127

Phn 5. kt cu b tng... 128

5.1. phm vi ............................................................................................................................ 128

5.2. cc nh ngha............................................................................................................ 128

5.3. k hiu............................................................................................................................. 132

5.4. cc tnh cht ca vt liu................................................................................... 138

5.5. cc trng thi gii hn ........................................................................................ 145

5.6. cc nghin cu thit k......................................................................................... 149

5.7. thit k kt cu chu un v chu lc dc trc...................................... 153

5.8. ct v xon.................................................................................................................. 168

5.9. d ng lc v d ng lc mt phn................................................................. 182

5.10. cc chi tit t ct thp .................................................................................... 195

5.11. trin khai ct thp v mi ni ct thp..................................................... 219

5.12. bn ............................................................................................................................ 230

5.13. cc cu kin ring bit ........................................................................................ 233

5.14. qui nh i vi cc loi kt cu ................................................................... 246

Phn 6. kt cu thp.. 268

6.1. phm vi ............................................................................................................................ 268

6.2. cc nh ngha ........................................................................................................... 268

6.3. k hiu............................................................................................................................. 272

6.4. vt liu........................................................................................................................... 279

6.5. cc trng thi gii hn ........................................................................................ 283

6.6. cc xem xt v mi v t gy.......................................................................... 285

6.7. cc yu cu v kch thc chung v chi tit ........................................... 300

Tiu chun thit k cu III

6.8. cu kin chu ko ...................................................................................................... 304

6.9. cu kin chu nn ...................................................................................................... 309

6.10. cc mt ct ch I chu un ................................................................................ 315

6.11. cc mt ct hp chu un................................................................................... 354

6.12. cc cu kin chu un khc............................................................................... 362

6.13. cc lin kt v mi ni ........................................................................................ 366

6.14. quy nh cho cc loi kt cu......................................................................... 384

Phn 9. mt cu v h mt cu... 390 9.1. phm vi ............................................................................................................................ 390

9.2. cc nh ngha............................................................................................................ 390

9.3. cc k hiu ................................................................................................................... 393

9.4. cc yu cu thit k chung ................................................................................ 393

9.5. cc trng thi gii hn ........................................................................................ 394

9.6. phn tch........................................................................................................................ 395

9.7. bn mt cu b tng ............................................................................................... 395

9.8. mt cu thp................................................................................................................ 401

Phn 10. nn mng 407 10.1. phm vi .......................................................................................................................... 407

10.2. cc nh ngha.......................................................................................................... 407

10.3. cc k hiu ................................................................................................................. 408

10.4. xc nh tnh cht ca t ............................................................................... 412

10.5. cc trng thi gii hn v cc h s sc khng .................................. 415

10.6. mng m rng........................................................................................................... 419

10.7. cc ng ...................................................................................................................... 448

10.8. cc khoan ................................................................................................................... 470

Phn 11. m, tr v tng chn. 494

11.1. phm vi .......................................................................................................................... 494

11.2. cc nh ngha.......................................................................................................... 494

11.3. k hiu........................................................................................................................... 495

11.4. cc tnh cht ca t v vt liu ................................................................. 496

11.5. cc trng thi gii hn v h s sc khng............................................ 497

11.6. cc m v tng chn thng thng ......................................................... 499

Tiu chun thit k cu IV

11.7. tr .................................................................................................................................. 504

11.8. tng c neo.............................................................................................................. 504

11.9. tng t n nh bng c hc (MSE)........................................................... 508

11.10. cc tng ch to sn theo m un .......................................................... 520

Phn 12. kt cu vi (cng) v o hm... 526

12.1. phm vi .......................................................................................................................... 526

12.2. cc nh ngha.......................................................................................................... 526

12.3. cc k hiu ................................................................................................................. 526

12.4. tnh cht ca t v vt liu .......................................................................... 530

12.5. trng thi gii hn v h s sc khng..................................................... 531

12.6. c trng thit k chung .................................................................................. 535

12.7. ng kim loi, kt cu vm ng v vm ....................................................... 539

12.8. kt cu bn nhp ln ............................................................................................. 541

12.9. kt cu hp bn........................................................................................................ 550

12. 10. ng b tng ct thp ......................................................................................... 555

12.11. cng hp b tng ct thp c ti ch v c sn v vm b tng ct thp c ti ch........................................................................

571

12.12. ng nha do nng .............................................................................................. 575

12.13. tm v hm bng thp ........................................................................................ 578

12.14. cc kt cu c 3 cnh bng b tng ct thp c sn .................... 582

Phn 13. lan can, ro chn 594

13.1. phm vi .......................................................................................................................... 594

13.2. cc nh ngha.......................................................................................................... 594

13.3. k hiu........................................................................................................................... 595

13.4. tng qut.................................................................................................................... 596

13.5. vt liu......................................................................................................................... 597

13.6. cc trng thi gii hn v cc h s sc khng .................................. 597

13.7. lan can ng t ................................................................................................ 598

13.8. lan can ng ngi i b ................................................................................. 611

13.9. lan can ng xe p ........................................................................................... 613

13.10. lan can dng kt hp ......................................................................................... 614

13.11. b va v ng ngi i b ............................................................................ 614

Tiu chun thit k cu V

Phn 14. khe co gi=n v gi cu. 615

14.1. phm vi... 615

14.2. cc nh ngha.......................................................................................................... 615

14.3. k hiu........................................................................................................................... 617

14.4. cc chuyn v v cc ti trng...................................................................... 619

14.5. cc khe co gimn ca cu ..................................................................................... 621

14.6. cc yu cu i vi cc gi cu ..................................................................... 629

14.7. cc quy nh thit k ring bit v gi...................................................... 633

14.8. cc tm ti trng v s neo c cc gi............................................... 654

14.9. bo v chng n mn............................................................................................ 655

Ghi ch: Cc cng thc, hnh v v bng c nu trong tng iu c biu th bng s hiu ca

chnh iu v thm mt ch s ph, v d 1.2.3.4.5-1, nhng khi chng c nhc n

ngay trong chnh iu th chng c biu th bng ch s ph. V d trong iu 1.2.3.5,

cng thc 1.2.3.4.5-2, ch gi l cng thc 2. Khi cng thc ny c nu bt k iu

no khc, n s c gi vi tn y , c ngha l cng thc 1.2.3.4.5-2. Quy c ny

cng dng cho cc bng v hnh v.

Tiu chun thit k cu 1

Phn 1 - Gii thiu chung

1.1. Phm vi

Cc quy nh ca B Tiu chun ny nhm dng cho cc cng tc thit k, nh gi v khi phc cc

cu c nh v cu di ng trn tuyn ng b. Tuy nhin n khng bao hm cc kha cnh an ton

ca cu di ng cho cc loi xe c gii, xe in, xe c bit v ngi i b. Cc quy nh ca B Tiu

chun ny khng dng cho cc cu dnh ring cho ng st, ng st ni (rail-transit) hoc cng

trnh cng cng. D kin mt phn b sung v thit k cu ng st s c bin son trong tng lai.

Vi cc cu loi , cc quy nh ca Tiu chun ny c th c p dng nu c thm nhng Tiu

chun thit k b sung khi cn thit.

B Tiu chun ny ch a ra nhng yu cu ti thiu cn cho an ton cng cng. Ch u t c th i

hi s linh hot ca thit k hoc cht lng vt liu v thi cng cao hn cc yu cu ti thiu.

Cc quy nh ca B Tiu chun ny da vo phng php lun Thit k theo h s ti trng v h s

sc khng (LRFD). Cc h s c ly t l thuyt tin cy da trn kin thc thng k hin nay v

ti trng v tnh nng ca kt cu. Nhng quan im an ton thng qua tnh do, tnh d, bo v chng

xi l v va chm c lu nhn mnh..

B Tiu chun ny c bin son, da trn Tiu chun thit k cu theo h s ti trng v h s sc

khng ca AASHTO, xut bn ln th hai (1998), bn in dng h n v quc t (SI). Phn gii thch

ca Tiu chun thit k cu theo h s ti trng v h s sc khng ca AASHTO, xut bn ln th hai,

bn in dng h n v quc t (SI), bao gm nhng thng tin c bn v b sung, cc khuyn ngh v ti

liu tham kho khc, v c th gip ch cho vic s dng B Tiu chun ny.

B Tiu chun ny a vo s dng ng ngha thng nht trong ton b ni dung nh sau:

T phi c ngha l yu cu theo ng quy nh ca Tiu chun.

T cn c ngha l rt nn u tin dng mt tiu chun b cho.

T c th c ngha l mt tiu chun c th c p dng nhng cng cho php p dng

mt tiu chun khc ca a phng c ti liu ph hp, b qua kim nghim v c ph

chun ph hp vi phng php thit k cu theo h s ti trng v h s sc khng.

H n v mt (h quc t) c dng thng nht trong B Tiu chun ny.


1.2. Cc nh ngha

Cu - Mt kt cu bt k vt khu khng di 6m to thnh mt phn ca mt con ng.

Sp - S thay i ln v hnh hc ca cu dn n khng th s dng c na.

Cu kin, thnh phn - L mt chi tit kt cu ring bit hoc mt t hp cc chi tit ca cu i hi

phi c xem xt thit k ring.

Thit k - Xc nh kch thc v cu to cc cu kin v lin kt ca cu.

Tui th thit k - Khong thi gian trong ngun gc thng k ca ti trng nht thi b da vo :

vi Tiu chun thit k cu ny l 100 nm.

Tnh do - Thuc tnh ca mt cu kin hoc lin kt cho php p ng khng n hi.

K s - Ngi chu trch nhim thit k cu.

nh gi - Vic xc nh kh nng chu ti ca mt cu hin c

Trng thi gii hn c bit - Trng thi gii hn lin quan n nhng s c nh ng t v va x

tu b, va x xe c vo cng trnh c cc chu k lp li vt qu tui th thit k ca cu.

Cu c nh - Cu c kh gii hn (tnh khng) c nh cho thng xe c hoc thng thuyn .

Hiu ng lc - Bin dng, ng sut hoc t hp ng sut (tc l lc dc trc, lc ct, m men un

hoc xon) gy ra do tc ng ca ti trng, ca nhng bin dng cng bc hoc ca cc thay i

v th tch.

Trng thi gi hn - iu kin m vt qua n th cu hoc cu kin ca cu ngng tho mbn cc quy

nh b c da vo thit k.

H s ti trng - H s xt n ch yu l s bin thin ca cc ti trng, s thiu chnh xc trong phn

tch v xc sut xy ra cng mt lc ca cc ti trng khc nhau, nhng cng lin h n nhng thng

k v sc khng thng qua qu trnh hiu chnh.

H s iu chnh ti trng - H s xt n tnh do, tnh d v tm quan trng trong khai thc

ca cu.

M hnh - S l tng ho kt cu dng cho mc ch phn tch kt cu.

Cu di ng - Cu c kh gii hn (tnh khng) c th thay i cho thng xe c hoc thng thuyn.

Kt cu c nhiu ng truyn lc - Kt cu c kh nng chu c cc ti trng b nh sau khi mt

i mt cu kin hoc lin kt chu lc chnh.


Sc khng danh nh - Sc khng ca mt cu kin hoc lin kt i vi ng lc c xc nh bi

nhng kch thc ghi trong h s hp ng v bi ng sut cho php, bin dng hoc cng c

ghi r ca vt liu.

Ch u t - C quan hoc c nhn c quyn lc php l quyt nh u t i vi cu.

S dng bnh thng - iu kin s dng cu khng bao gm : loi xe c php c bit, ti trng

gi vi tc vt qu 25 m/s v cc s c c bit k c xi l.

Khi phc - Qa trnh m sc chu ti ca cu c khi phc hoc nng cao.

H s sc khng - H s ch yu xt n s bin thin ca cc tnh cht ca vt liu, kch thc kt

cu v tay ngh ca cng nhn v s khng chc chn trong d on v sc khng, nhng cng lin h

n nhng thng k v cc ti trng thng qua qu trnh hiu chnh.

H s ch yu xt n s bin thin ca cc tnh cht ca vt liu, kch thc kt cu v tay ngh ca cng nhn v s khng chc chn trong d on v sc khng, nhng cng lin h n nhng thng k v cc ti trng thng qua qu trnh hiu chnh.

Tui th s dng - Khong thi gian cu c d kin khai thc an ton

Trng thi gii hn s dng - Trng thi gii hn lin quan n ng sut, bin dng v vt nt.

Trng thi gii hn cng - Trng thi gii hn lin quan n cng v n nh.

1.3. Trit l thit k

1.3.1. Tng qut

Cu phi c thit k theo cc trng thi gii hn quy nh t c cc mc tiu thi cng c, an

ton v s dng c, c xt n cc vn : kh nng d kim tra, tnh kinh t v m quan nh nu

iu 2.5.

Bt k dng phng php phn tch kt cu no th phng trnh 1.3.2.1-1 lun lun cn c tha mbn

vi mi ng lc v cc t hp c ghi r ca chng.

1.3.2. Cc trng thi gii hn

1.3.2.1. Tng qut

Mi cu kin v lin kt phi tha mbn Phng trnh 1 vi mi trng thi gii hn, tr khi c quy

nh khc. i vi cc trng thi gii hn s dng v trng thi gii hn c bit, h s sc khng c

ly bng 1,0, tr trng hp vi bu lng th phi p dng quy nh iu 6.5.5. Mi trng thi gii hn c coi trng nh nhau.

i Yi Qi Rn = Rr (1.3.2.1-1)

vi :

i vi ti trng dng gi tr cc i ca Yi:

i= D R l 0,95 (1.3.2.1-2)


i vi ti trng dng gi tr cc tiu ca Yi:

0,11

IRD

i = (1.3.2.1-3)

trong :

Yi = h s ti trng : h s nhn da trn thng k dng cho ng lc. = h s sc khng: h s nhn da trn thng k dng cho sc khng danh nh c ghi

cc Phn 5, 6, 10, 11 v 12. i = h s iu chnh ti trng; h s lin quan n tnh do, tnh d v tm quan trng

trong khai thc. D = h s lin quan n tnh do c ghi iu 1.3.3. R = h s lin quan n tnh d c ghi iu 1.3.4. I = h s lin quan n tm quan trng trong khai thc c ghi iu 1.3.5. Qi = ng lc Rn = sc khng danh nh Rr = sc khng tnh ton : Rn

1.3.2.2. Trng thi gii hn s dng

Trng thi gii hn s dng phi xt n nh mt bin php nhm hn ch i vi ng sut, bin dng

v b rng vt nt di iu kin s dng bnh thng.

1.3.2.3. Trng thi gii hn mi v ph hoi gin

Trng thi gii hn mi phi c xt n trong tnh ton nh mt bin php nhm hn ch v bin

ng sut do mt xe ti thit k gy ra vi s chu k bin ng sut d kin.

Trng thi gii hn ph hoi gin phi c xt n nh mt s yu cu v tnh bn ca vt liu theo

Tiu chun vt liu.

1.3.2.4. Trng thi gii hn cng

Trng thi gii hn cng phi c xt n m bo cng v s n nh cc b v n nh

tng th c d phng chu c cc t hp ti trng quan trng theo thng k c nh ra cu

chu c trong phm vi tui th thit k ca n.

1.3.2.5. Trng thi gii hn c bit

Trng thi gii hn c bit phi c xt n m bo s tn ti ca cu khi ng t hoc l ln

hoc khi b tu thu, xe c va, c th c trong iu kin b xi l.


1.3.3. Tnh do

H kt cu ca cu phi c nh kch thc v cu to m bo s pht trin ng k v c th

nhn thy c ca cc bin dng khng n hi trng thi gii hn cng v trng thi gii hn

c bit trc khi ph hoi.

C th gi nh rng cc yu cu v tnh do c tho mbn i vi mt kt cu b tng sc khng

ca lin kt khng thp hn 1,3 ln ng lc ln nht do tc ng khng n hi ca cc cu kin lin k

tc ng ln lin kt .

S dng cc thit b tiu nng c th c coi l bin php lm tng tnh do.

i vi trng thi gii hn cng :

D 1,05 cho cu kin v lin kt khng do.

= 1,00 cho cc thit k thng thng v cc chi tit theo ng Tiu chun ny.

0,95 cho cc cu kin v lin kt c cc bin php tng thm tnh do quy nh vt qu

nhng yu cu ca Tiu chun ny

i vi cc trng thi gii hn khc : D = 1,00

1.3.4. Tnh d

Cc kt cu c nhiu ng truyn lc v kt cu lin tc cn c s dng tr khi c nhng l do bt

buc khc.

Cc b phn hoc cu kin chnh m s h hng ca chng gy ra sp cu phi c coi l c nguy

c h hng v h kt cu lin quan khng c tnh d, cc b phn c nguy c h hng c th c xem

l ph hoi gin.

Cc b phn hoc cu kin m s h hng ca chng khng gy nn sp cu c coi l khng c

nguy c h hng v h kt cu lin quan l d.


R 1,05 cho cc b phn khng d

= 1,00 cho cc mc d thng thng

0,95 cho cc mc d c bit

i vi cc trng thi gii hn khc:

R = 1,00

1.3.5. Tm quan trng trong khai thc

iu quy nh ny ch dng cho trng thi gii hn cng v trng thi gii hn c bit.


Ch u t c th cng b mt cu hoc bt k cu kin hoc lin kt no ca n l loi cu quan trng

trong khai thc.


I 1,05 cho cc cu quan trng

= 1,00 cho cc cu in hnh

0,95 cho cc cu tng i t quan trng

i vi cc trng thi gii hn khc:

I = 1,00


Phn 2 - Thit k tng th v c im v tr cu

2.1. Phm vi cp

Quy nh cc yu cu ti thiu v kh gi hn, bo v mi trng, m quan, nghin cu a cht, kinh

t, kh nng thng xe, tnh bn, kh nng thi cng, kh nng kim tra v kh nng duy tu c. Cc yu

cu ti thiu v an ton giao thng c tm lc.

Cc yu cu ti thiu v thit b thot nc v cc bin php t bo v chng nc v nc mn cng

c cp.

V nhiu cu b ph hoi l do nguyn nhn xi l nn cc vn v thu vn v thu lc c cp

chi tit.

2.2. Cc nh ngha

Bi tch - S tch li chung v dn dn ph sa hoc nng cao trc dc ca lng sng do ph sa bi lng.

L kim tra xi cu - Lu lng l dng tnh ton xi l nn mng khi phi kim ton cu vt

sng theo trng thi gii hn c bit. Tr trng hp c ch nh khc ca Ch u t, l kim ton xi

cu phi dng l 500 nm.

Vng trng - Vng khng c chng ngi, tng i bng pha ngoi mp ca ln xe cho cc xe

i nhm c th quay li c. Ln xe y khng bao gm l hoc ln ph.

Kh gii hn (tnh khng) - Khong khng gian trng khng c chng ngi, c dnh cho thng xe

trn cu hoc thng xe di cu hoc thng thuyn di cu.

Xi mn - S h thp chung v dn dn trc dc ca lng sng do b xi lu ngy.

Lu lng l thit k - Lu lng nc ln nht m cu phi chu khng vt qu cc hn ch ca

thit k c duyt.

L thit k xi cu - Lu lng dng tnh ton xi l nn mng khi thit k cu vt sng theo

trng thi gii hn (TTGH) cng v TTGH s dng. Tr trng hp c ch nh khc ca Ch u

t, l thit k xi l cn phi dng l 100 nm.

L thit k khu cu - Lu lng nh v mc nc cao nht ( c tnh n nh hng ca sng hay

dng triu, v nh hng ca nc dnh khi cn thit), m ng vi n cu vt sng hay vt qua vng

ngp l c thit k m khng lm kt cu b ngp hay khng gy ngp lt qu mc cho php. Tr khi

c ch nh khc ca Ch u t, l thit k cho khu cu phi dng l 100 nm.


H cha nc - Phng tin qun l nc ma khng cho chy qua v x nht thi qua kt cu x

nc n h thng dn h lu.

Rnh nh git - Vt lm y cu kin lm nc chy trn mt nh xung.

L 500 nm - L do ma bô v/hoc triu c tn sut xy ra bng hoc vt qu 0,2% trong bt k

nm cho trc no.

Xi chung - Xi sng hoc trn bî m khng tp trung tr hoc vt cn khc trn dng chy.

mt con sng xi chung thng tc ng n ton b hoc gn ht chiu rng ca sng do s thu hp

dng chy gy ra.

Thu lc - Khoa hc lin quan n c trng v dng ca cht lng, c bit l trong ng cng

v knh, sng.

Thu vn - Khoa hc lin quan n s xut hin, phn b v tun hon ca nc trn tri t, bao gm

ma, dng chy v nc ngm.

Xi cc b - sng hoc trn bî tp trung m tr hoc vt cn khc trn dng chy.

L hn hp - Dng l do hai hoc nhiu nguyn nhn gy ra nh triu cung km theo gi bô gy

ra trn b .

L mt trm nm - L do ma v /hoc triu c kh nng xy ra bng hoc vt xc sut 1% trong

bt k nm cho trc no.

L trn - Dng l m nu vt qu s gy chy trn qua ng hoc cu, vt qua ng phn chia lu

vc hoc qua kt cu x khn cp. iu kin xi xu nht c th do l trn gy ra.

Cu x l - Khong trng trong nn ng bî sng cho dng chy bî vut qua.

Kt cu chnh tr sng - Mt kt cu no c xy dng trong dng sng hoc trn k bn hoc

gn b nn dng sng, gy bi tch, gim xi l, hoc bng mt s cch khc lm thay i dng

chy v ch bi lng dng sng.

L thot nc, ng thot nc - Thit b thot nc qua mt cu.

B rng ng ngi i - Khong khng gian trng dnh cho ngi i b.

Triu cng - Triu bin tng xy ra hai tun 1 ln khi trng trn v u tun trng.


Sng n nh - iu kin tn ti khi sng c dc lng v mt ct ngang cho php vn chuyn nc

v trm tch t lu vc thng ngun m khng c xi mn, bi tch hoc xi l b ng k.

a mo sng - Nghin cu v sng v b^i ca n c xt n a hnh, hnh thi chung ca b mt t

v nhng thay i xy ra do xi l hoc bi tch.

Siu cao - nghing ca mt ng cn bng mt phn lc ly tm tc ng vo xe trn ng

cong nm.

Thu triu - Chu k nng v h ca i dng do hiu ng ca mt trng v mt tri tc ng ln tri

t quay.

Lu vc - Vng a phng nm trong ng phn thu, thng ch c mt li x; tng din tch thot

nc gy nn dng chy mt im duy nht.

ng thu - Dng nc, sng , ao, h, hoc i dng.

Khu thot nc - Chiu rng hoc khong trng ca cu giai on quy nh, thng c o

theo hng chnh ca dng chy.

2.3. Cc c trng v tr

2.3.1. V tr tuyn

2.3.1.1. Tng qut

Khi chn v tr cu phi qua phn tch cc phng n c xt v cc mt kinh t, k thut, x^ hi v mi

trng c lin quan cng nh xt n gi duy tu v kim tra kt cu ca n v vi tm quan trng tng

i ca cc mi lin quan trn .

Ch tho ng ti ri ro c th xy ra, cn nghin cu chn v tr cu tt :

Tho m^n cc iu kin gy ra bi chng ngi cn vt;

Thun li cho vic thc hnh hiu qu cng tc thit k, thi cng, khai thc, kim tra v duy tu;

Cung cp mc mong mun v phc v vn ti v an ton; v

Gim thiu cc tc ng bt li ca ng n mi trng.

2.3.1.2. Cc im vt sng v bi sng

Phi xc nh cc im vt sng c xt n gi thnh xy dng ban u v vic ti u ho tng gi

thnh cng trnh, bao gm cc cng trnh chnh tr sng v cc bin php duy tu, bo dng cn thit

gim xi l. Nghin cu phng n cc v tr vt sng cn bao gm cc nh gi v:


Cc c trng thu vn v thu lc ca sng v vng ngp ca n, bao gm s n nh dng l lch

s, bin v chu k ca thu triu cc v tr vt sng;

nh hng ca cu i vi phn b l v nguy c xi mng cu;

kh nng gy nn nhng ri ro mi hoc lm tng nhng ri ro do l;

Nhng tc ng n mi trng trn sng v bî.

Cu v ng u cu bî sng cn c nh v v thit k c xt n cc mc ch v mc tiu qun

l bî sng gm:

Ngn nga vic s dng v pht trin khng kinh t, nhiu ri ro hoc khng tho ng i vi

vng bî sng;

Trnh nhng xm phm ln v chiu ngang cng nh chiu dc ni c th;

Gim n mc ti thiu cc tc ng bt li ca ng v gim bt cc tc ng khng trnh c

ni c th;

Ph hp vi cc yu cu ca B Nng nghip v pht trin nng thn

Bi tch v xi mn di hn

Cc cam kt c chp thun v mt bo v mi trng.

2.3.2. B tr v tr cu

2.3.2.1. Tng qut

V tr v hng tuyn ca cu cn c chn tho m^n cc yu cu v an ton giao thng c trn

cu v di cu. Cn xt n cc thay i c th c trong tng lai v hng hoc chiu rng ca

ng sng, ng b hoc ng st m cu vt qua.

Ti ni thch hp cn xt trong tng lai c thm cc cng trnh cho cc loi giao thng khc hoc m

rng cu.

2.3.2.2. An ton giao thng

2.3.2.2.1. Bo v kt cu

Phi xt n s i li an ton ca xe c trn v di cu. Ri ro do xe i nhm trong khu trng cn

c gim n mc ti thiu bng cch t nhng chng ngi vi mt c ly an ton ngoi ln xe.


Ct tr hoc ca cc kt cu khc mc cu c b tr ph hp vi khi nim vng trng nh c nu

trong Tiu chun Thit k ng. ni do nhng hn ch thc t v gi thnh kt cu, loi hnh kt

cu, lu lng v tc thit k ca xe, vic b tr nhp, mt nghing v i th khng thc hin c

theo Tiu chun Thit k ng th tr v tng cn c dng lan can hoc thit b ro chn khc bo

v . Lan can hoc thit b ro chn khc, nu c, cn cho chu lc c lp, vi mt quay v pha

ng ca n phi cch xa mt m tr t nht l 600mm, nu khng th phi t ro chn cng.

Mt ca lan can hoc thit b khc phi t pha ngoi ca l ng t nht l 600mm.

2.3.2.2.2. Bo v ngi s dng

Lan can phi t dc theo mp kt cu ph hp vi nhng yu cu Phn 13.

Tt c cc kt cu bo v phi c y cc c trng b mt v s chuyn tip nh hng li mt

cch an ton cc xe i sai.

Trong trng hp cu di ng, cc bin bo nguy him, n, chung, ca, ro chn v cc thit b an

ton khc phi c t bo v ngi i b, ngi i xe p v t. Cc thit b ny phi c thit

k chng hot ng trc khi m nhp di ng v duy tr cho ti khi nhp ny ^ c ng li hon

ton.

Nu Ch u t khng yu cu khc th cc ng ngi i b phi c bo v bng ro chn.

2.3.2.2.3. Tiu chun hnh hc

Cc yu cu ca Tiu chun Thit k ng phi c tho m^n, trng hp c bit phi c chng

minh v lp h s. Chiu rng ca l ng v kch thc ca ro chn giao thng phi p ng cc yu

cu ca Ch u t.

2.3.2.2.4. Mt ng

Mt ng trn cu phi c c tnh chng trt, c sng ng, thot nc v siu cao phi ph hp

vi Tiu chun Thit k ng

2.3.2.2.5. Va tu thy

Kt cu cu phi c bo v chng lc va tu bng b chng va, p hoc bo v v /hoc phi c

thit k chu c ng lc va tu nh yu cu iu 3.14.15.


2.3.3. Tnh khng

2.3.3.1. Thng thuyn

Giy php xy dng cu qua ng thu c thng thuyn phi do Cc ng sng Vit Nam hoc

Cc Hng hi Vit nam cp. Kh gii hn thng thuyn c v chiu ng ln chiu ngang phi c

Ch u t xc lp vi s cng tc ca Cc ng sng Vit Nam hoc Cc Hng hi Vit Nam. Tr

khi c ch nh khc, kh gii hn thng thuyn phi tun theo Bng 2.3.3.1.1, ly t TCVN

5664-1992

Bng 2.3.3.1.1 - Kh gii hn thng thuyn trn cc sng c thng thuyn

Kh gii hn ti thiu trn mc nc cao c chu k 20nm (m)

Theo chiu ngang Cp ng sng Cu qua sng Cu qua knh

Theo chiu thng ng (trn ton chiu rng)

I 80 50 10 II 60 40 9 III 50 30 7 IV 40 25 6 (thch hp)

5 (ti thiu) V 25 20 3,5 VI 15 10 2,5

2.3.3.2. Kh gii hn ng ca ng b

Kh gii hn ng ca cc kt cu ng b phi ph hp vi Tiu chun Thit k ng. Cn nghin

cu kh nng gim kh gii hn ng do ln ca kt cu cu vt. Nu ln d kin vt qu 25 mm

th cn c cng thm vo kh gii hn ^ c quy nh.

Kh gii hn ng ca cc gi bin bo v cc cu vt cho ngi i b phi ln hn kh gii hn

kt cu ca ng 300mm, v kh gii hn ng t mt ng n thanh ging ca kt cu dn vt

qua pha trn khng c nh hn 5300mm.

2.3.3.3. Kh gii hn ngang ca ng b

Chiu rng cu khng c nh hn chiu rng ca on ng u cu bao gm c l hoc b va,

r^nh nc v ng ngi i.

Kh gii hn ngang di cu cn tho m^n cc yu cu ca iu 2.3.2.2.1.

Khng c vt th no trn hoc di cu, ngoi ro chn, c nh v cch mp ca ln xe

di 1200mm. Mt trong ca ro chn khng c t cch mt ca vt th hoc mp ca ln

xe di 600mm.

2.3.3.4. Cu vt ng st


Cc kt cu c thit k vt ng st phi ph hp vi kh gii hn c quy nh cc Hnh 1 v 2 v tun theo cc yu cu c bit ca Ch u t v Cc ng st Vit Nam.

Ghi ch: Kh gii hn di y c s dng cho tuyn thng; vi tuyn cong cu theo 22TCN - 18 - 1979 -

Ph lc 1

Cao nh ray

____ Cho cc cng trnh vt pha trn ng st dng sc ko hi nc v izen ------- Cho cc cng trnh vt pha trn ng st dng sc ko in xoay chiu S trong ngoc n dng khi c kh khn v chiu cao

Hnh 2.3.3.4-1 - Kh gii hn ng st trn ng thng trong khu gian (ng st kh 1000mm)

Cao nh ray

___ Cho cc cng trnh vt pha trn ng st dng sc ko hi nc v izen ------ Cho cc cng trnh vt pha trn ng st dng sc ko in xoay chiu S trong ngoc n dng khi c kh khn v chiu cao

Hnh 2.3.3.4-2 - Kh gii hn ng st trn ng thng trong khu gian (ng st kh 1435 mm)


2.3.4. Mi trng

Tc ng ca cu v ng u cu n dn c a phng, cc di tch lch s, t trng v cc vng

nhy cm v m quan, mi trung v sinh thi u phi c xem xt. Thit k phi tun theo mi lut

l quy nh v mi trng c lin quan, phi xem xt v a mo dng sng, h qu ca xi l lng

sng, cun tri cy c gia c nn p v trong trng hp cn thit cn phi xem xt nhng tc ng

n ng lc dng triu ca sng.

2.4. Kho st mng

2.4.1. Tng qut

Vic kho st tng ph, bao gm cng tc khoan v th nghim t phi c thc hin theo cc quy

nh iu 10.4 cung cp cc thng tin thch hp v y cho thit k kt cu phn di. Loi

hnh v gi thnh mng phi c xem xt trong nghin cu kinh t v m quan v nh v v chn

phng n cu.

2.4.2. Nghin cu a hnh

Phi thit lp bn hin ti ca cu bng bn a hnh v nh. Nghin cu ny bao gm lch s v

tr trong qu trnh di chuyn ca cc khi t, xi l ca t v s un khc ca sng.

2.5. Mc ch thit k

2.5.1. An ton

Trch nhim chnh ca k s thit k l phi m bo an ton cho dn chng.

2.5.2. Kh nng khai thc

2.5.2.1. Tnh bn

2.5.2.1.1. Vt liu

H s hp ng phi i hi vt liu c cht lng v vic ch to v lp t vi tiu chun cao.

Thp kt cu phi c tnh t bo v, hoc c bo v bng h thng sn c tui th cao hoc h thng

bo v ca-tt.

Ct thp v tao cp d ng lc trong b tng vng c hi nc mn hoc cha nc mn phi c

bo v bi mt t hp ph keo -p-xy thch hp v /hoc c m in, hoc bo v ca-tt. Bn ngoi

cn c lp b tng bo h khng b r, c t trng v thnh phn ho hc ca b tng thch hp, bao

gm c bin php sn b mt b tng chng thm kh


Cc to thp d ng lc trong ng bc phi c bm va lp lng ng hoc bng cch khc

bo v chng g.

Phi c bin php bo v cc vt liu d b h hng do bc x mt tri v nhim khng kh.

Phi xt n tnh bn ca vt liu tip xc trc tip vi t v nc.

2.5.2.1.2. Cc bin php t bo v

Cn lm nhng r^nh xoi nh nc lin tc mt di ca mt cu b tng v khng cch mt u

dm qu 250mm. Ni mt cu b t qu^ng bi cc khe co gi^n c bt kn th mt nh m tr,

tr b gi cn lm dc t nht l 5% ra pha mp. Vi cc khe co gi^n kiu h, dc ny phi khng

nh hn 15%. Trng hp dng khe co gi^n kiu h, gi cu phi c bo v chng tip xc vi

nc mn v rc ri.

Mt ng mi ni mt cu cn gin on v phi lm cho m thun qua b mi ni mt cu.

Vn khun thp phi c bo v chng g theo yu cu ca Ch u t.

2.5.2.2. Kh nng kim tra

Phi lp t cc thang, li i b, li i ven, h vo c np y v cp in chiu sng nu cn, kim

tra cu khi m cc phng tin kim tra khc khng thc hin c.

Ni c th, phi lm cc li vo bn trong cc ngn ca cu kin hp vi chiu cao thng thu cao

v ti cc mt tip xc, ni c cc dch chuyn tng i, c th kim tra th cng v bng mt.

2.5.2.3. Kh nng duy tu

Cn trnh dng cc h kt cu kh duy tu. Ni m kh hu v mi trng giao thng c th nh hng

xu n mc c th phi thay mt cu trc khi ht tui th s dng ca n th phi quy nh trong h

s hp ng v vic thay mt cu hoc phi lp t thm kt cu chu lc.

Din tch xung quanh b gi v di khe co gi^n cn c thit k thun tin cho vic kch, lm v

sinh, sa cha v thay gi cu v khe co gi^n.

im kch phi c th hin trong bn v v kt cu phi c thit k chu lc kch ghi iu 3.4.3.

Cn trnh lm nhng hc v gc khng vo c. Cn phi trnh lm hoc phi lm cho chc chn cc

hc m c th dng lm ni c tr cho ngi v sc vt.


2.5.2.4. Kh nng thng xe thun tin

Mt cu phi c thit k cho php xe c i li m thun. Phi t bn chuyn tip gia m cu v

ng dn ln cu. Dung sai xy dng lin quan n tit din mt cu ^ c hon thin phi c ch

r trong bn v hoc trong cc ch dn hoc cc quy nh ring.

Cn phi gim n mc ti thiu s lng khe co gi^n. Cc g khe co gi^n mt cu b tng l trn mt

ng phi c bo v chng mi mn v nt v. Bn thit k ch to trc cc khe co gi^n cn

quy nh rng cm ni phi c lp t nh mt khi lin.

Mt cu b tng khng c lp ph ban u cn c lp b sung dy 10mm cho php hiu chnh li

mt cu do mi mn v b li chiu dy mt i do ma st.

2.5.2.5. Cc tin ch cng cng khc

ni c yu cu cn phi lm cc gi v bo m cho cc tin ch cng cng khc c truyn qua.

2.5.2.6. Bin dng

2.5.2.6.1. Tng qut

Cng trnh Cu phi c thit k trnh nhng hiu ng khng mong mun v kt cu hoc tm l

do bin dng gy nn. Khi cc gii hn v vng v chiu cao ^ c la chn th tr cc bn mt

cu trc hng, bt c s thay i no so vi thc t ^ c xem xt cn thn trc v mnh v

vng u phi c i chiu vi thit k xc nh xem c hon thin khng.

Nu dng phng php phn tch ng phi tun th cc nguyn tc v yu cu ^ nu ra iu 4.7.

2.5.2.6.2. Tiu chun v vng

Cc tiu chun phn ny, ngoi cc quy nh cho mt cu trc hng, c xem nh l tu chn. Cc

quy nh cho mt cu trc hng c coi l bt buc.

Trong khi p dng cc tiu chun ny, ti trng xe cn bao gm lc xung kch. Nu Ch u t yu cu

kim tra vng th c th p dng cc nguyn tc sau:

Khi nghin cu vng tuyt i ln nht, tt c cc ln xe thit k phi c t ti v tt c cc

cu kin chu lc cn coi l vng ln nh nhau;

V thit k cu lin hp, mt ct ngang thit k phi bao gm ton b chiu rng ca ng v

nhng b phn lin tc v kt cu ca lan can, ng ngi i v ro chn gia;


Khi nghin cu chuyn v tng i ln nht, s lng v v tr ca cc ln t ti phi chn cho

hiu ng chnh lch bt li nht;

Phi dng hot ti ca t hp ti trng s dng trong bng 3.4.1.1 k c lc xung kch IM;

Hot ti phi ly theo iu 3.6.1.3.2;

Cc quy nh ca iu 3.6.1.1.2 cn c p dng; v

i vi cu cho c th dng mt ct ngang thng gc, vi cu cong v va cong va cho c th

dng mt ct ngang xuyn tm .

Trong khi thiu cc tiu chun khc, cc gi hn v vng sau y c th xem xt cho kt cu thp,

nhm v b tng.

Ti trng xe ni chung............................................................................................................L/800,

Ti trng xe v/hoc ngi i b .........................................................................................L/1000,

Ti trng xe phn hng ........................................................................................................L/300,

Ti trng xe v/hoc ngi i b phn hng........................................................................L/375.

(L- chiu di nhp)

i vi dm thp I v dm t hp cn p dng cc quy nh ca iu 6.10.5 v 6.10.10.2 v kim tra

vng thng xuyn qua kim tra ng sut bn cnh dm.

Cc quy nh sau y c dng cho mt cu bng bn trc hng:

Ti trng xe trn bn mt cu .................................................................................................L/300,

Ti trng xe trn sn ca mt cu thp trc hng................ ...................................... ...... L/1000,

Ti trng xe trn sn ca mt cu thp trc hng ( vng tng i

ln nht gia 2 sn cnh nhau) ............................................................................................ 2,5mm

2.5.2.6.3. Tiu chun la chn t l chiu di - chiu cao nhp

Nu ch u t yu cu kim tra t l chiu di - chiu cao nhp, c th xem xt dng cc gii hn

Bng 1 khi thiu cc tiu chun khc, trong S l chiu di ca bn v L l chiu di ca nhp, n v

u l mm. Nu dng, cc gii hn trong Bng 1 phi tnh cho ton chiu cao, nu khng c ghi ch.


Bng 2.5.2.6.3-1 - Chiu cao ti thiu thng thng dng cho cc kt cu phn trn c chiu cao khng i

Kt cu phn trn

Chiu cao ti thiu (gm c mt cu) (khi dng cc cu kin c chiu cao thay i th phi hiu chnh cc gi tr c tnh n nhng thay i v cng tng i ca cc mt ct m men dng v m)

Vt liu Loi hnh Dm gin n Dm lin tc

Bn c ct thp ch song song vi phng xe chy

1.2 (S + 3000)

30 S + 3000 165 mm

30 Dm T 0,070L 0,065L

Dm hp 0,060L 0,055L

B tng ct thp

Dm kt cu cho ngi i b 0,035L 0,033L

Bn 0,030L165mm 0,027L 165mm Dm hp c ti ch 0,045L 0,04L

Dm I c sn 0.045L 0,04L

Dm kt cu cho ngi i b 0,033L 0,030L

B tng d ng

lc

Dm hp lin k 0,030L 0,025L

Chiu cao ton b ca dm I lin hp 0,040L 0,032L

Chiu cao ca phn dm I ca dm I lin hp 0,033L 0,027L

Thp

Gin 0,100L 0,100L

2.5.2.7. Xt n vic m rng cu trong tng lai

2.5.2.7.1. Dm bin trong cu nhiu dm

D khng xt n vic m rng trong tng lai th nng lc chu ti ca dm bin cng khng c

thp hn nng lc chu ti ca dm bn trong.

2.5.2.7.2. Kt cu phn di

Khi d kin s m rng cu trong tng lai th cn xem xt thit k kt cu phn di c th m

rng c.

2.5.3. Kh nng thi cng

Cu phi c thit k sao cho vic ch to v lp rp c th thc hin khng qu kh khn hoc pht

sinh s c v cc ng lc lp rp nm trong gii hn cho php.


Khi phng php thi cng ca cu khng r rng hoc c th gy nn ng sut lp rp khng chp nhn

c th t nht phi c mt phng php kh thi c nu trong h s hp ng. Nu thit k i hi

phi c mt s thanh tng cng tm v hoc tr khi lp rp theo phng php c chn th cc ch

dn v yu cu ny phi c ghi trong h s hp ng.

Cn trnh cc chi tit hn nhng ch hp hoc phi b tng qua nhng khe ct thp dy c.

Cn xt n cc iu kin kh hu v thu lc c th nh hng n vic xy dng.

2.5.4. Tnh Kinh t

2.5.4.1. Tng qut

Loi hnh kt cu, chiu di nhp v vt liu phi c la chn c xt y n gi thnh d n. Cn

xt n chi ph tng lai trong tui th thit k ca cu. Cc nhn t a phng nh vt liu ti ch,

ch to, v tr ca cc tr ngi trong vn chuyn v lp rp cng phi c xem xt.

2.5.4.2. Phng n so snh

Trong trng hp c bit khi cc nghin cu v kinh t khng a ra c s la chn r rng, Ch u

t c th yu cu chun b cc phng n so snh v u thu cnh tranh. Thit k ca cc phng n

so snh phi c cng an ton, tnh s dng c v gi tr thm m.

Cu di ng qua ng thu c thng thuyn cn trnh khng nh ngay l kh thi b sung. Ni c kin

ngh lm cu di ng th t nht cng phi a vo mt phng n cu c nh trong so snh kinh t.

2.5.5. M quan cu

Cng trnh Cu phi c b sung v p cho cnh quan xung quanh, c hnh dng p v to dng

kho khon.

Ngi k s cn tm chn dng p cho kt cu bng cch ci thin bn thn hnh dng v quan h gia

cc cu kin. Cn trnh p dng cch lm p khng bnh thng v phi kt cu.

Cn xem xt cc ch dn sau y:

Cc phng n thit k khng c tr hoc t tr hn cn c nghin cu trong giai on chn a

im, v tr v nghin cu chi tit hn trong giai on thit k s b.

Hnh dng tr phi ph hp vi hnh dng v chi tit ca kt cu phn trn.


Cn trnh nhng thay i t ngt v hnh dng cu kin v loi hnh cu kin. Khi khng th trnh

c ranh gii gia cc loi hnh kt cu khc nhau cn to dng chuyn tip hi ho gia chng.

Khng c b qua m cn ch ti cc chi tit nh ng thot nc mt cu.

Nu buc phi dng kt cu chy di do yu cu k thut hoc l do kinh t, phi chn h kt cu

c b ngoi thng thong v khng ri rm.

ni no c th, cn trnh dng kt cu cu lm vt gn cc bng thng tin, bin ch dn ng hoc chiu sng.

Cc thanh ngang tng cng bn bng khng c l chnh din tr cc thanh gn gi.

vt khe ni su, cn u tin la chn kt cu dng vm.

2.6. Thu vn v thu lc

2.6.1. Tng qut

Cc nghin cu v thu vn v thu lc v nhng nh gi v v tr vt sng phi c hon thnh nh

mt phn ca thit k s b. Chi tit ca cc nghin cu ny cn tng xng vi tm quan trng v

nhng ri ro lin quan ca kt cu.

Cc kt cu tm cho Nh thu dng hoc phc v giao thng trong qu trnh xy dng phi c thit

k c xt n an ton ca ngi qua li v cc ch s hu lin i, cng nh l gim thiu tc ng ln

ti nguyn thin nhin trong vng ngp l. Ch u t c th cho php sa li cc yu cu thit k ph

hp vi thi gian phc v ^ nh v ri ro v l ca kt cu tm. H s hp ng v kt cu ph phi

m t trch nhim v cc ri ro tng ng c tha nhn bi C quan ng b v Nh thu.

Khi nh gi cc phng n cu phi xt n n nh dng chy, nc dnh, phn b dng chy, tc

chy, kh nng xi l, ri ro do l, ng lc triu ( ni c) .

2.6.2. S liu hin trng

K hoch thu thp s liu c th hin trng phi bao gm xem xt v:

Thu thp s liu kho st hng khng v mt t vi c ly thch hp thng lu v h lu cu

cho dng ch v b^i sng;

c tnh cc yu t v nhm ca dng ch v b^i sng trong phm vi b ngp c nghin cu;


Ly mu vt liu di y sng su xc nh chc chn cc c trng ca vt liu dng

cho tnh xi;

Khoan tng ph;

Cc yu t nh hng n cc mc nc , bao gm mc nc cao t sng, h cha , u tu, cc kt

cu khng ch l v triu v cc bin php khai thc;

Cc nghin cu v bo co hin c ;

Thng tin lch s sn c v c tnh cu sng v s lm vic ca kt cu trong cc t l trc kia,

bao gm xi l quan st c, xi l b v h hi v kt cu do vt tri;

Nhng thay i v a mo dng sng.

2.6.3. Phn tch thu vn

Ch u t phi xc nh quy m ca cc nghin cu thu vn da trn vic phn loi ng b theo

chc nng, lut l hin hnh v tai ho l lt ti hin trng.

Cc l sau y cn c iu tra nghin cu tho ng trong nghin cu thu vn:

Nhm m bo tho m^n cc tnh nng thu lc ca cng trnh cu l mt b phn ca tuyn

ng, m bo tm quan trng ca cu trn tuyn, cng nh nh gi s nguy him ca l v

tho m^n cc yu cu trong qun l vng ngp nc l thit k khu cu (xt l 100 nm tr khi

c ch nh khc ca Ch u t).

Nhm nh gi s ri ro cho nhng ngi s dng ng b v nh gi h hi cho cu v ng

vo cu- L thit k xi cu ( xt l 100 nm, tr khi c ch nh khc ca Ch u t).

Nhm iu tra nghin cu tnh thch hp ca nn mng cu trong vic chng xi l-L kim tra xi

cu (xt l 500 nm tr khi c ch nh khc ca Ch u t).

nh chun cc mc nc v nh gi tnh nng ca cc cng trnh hin c - Cc l lch s.

nh gi cc iu kin mi trng- Cc thng tin v lu lng dng chy c bn hoc dng chy

lu lng thp v cc cng trnh i qua ca sng, bin triu cng.

i vi cc cng trnh vt qua cc ngun ti nguyn bin/ ca sng, phi iu tra nghin cu nh

hng n bin triu ca s dng cao mc nc bin .

2.6.4. Phn tch thu lc

2.6.4.1. Tng qut

Ngi k s phi dng cc m hnh phn tch v cc k thut ^ c Ch u t duyt v ph hp vi

mc yu cu ca phn tch.


2.6.4.2. n nh ca dng chy

Phi nghin cu nh gi s n nh ca dng chy v xc nh tc ng ca cng trnh ln dng

chy. Cc hng mc sau y phi c xem xt:

Khc sng ang xi, ang bi hay trng thi cn bng;

i vi im vt sng gn ng^ ba sng cn xt: hiu ng ca dng ch v dng ph trong cc

qu trnh l, tc , phn b dng, chuyn dch ng v ngang ca dng v hiu ng ca cc iu

kin ni trn i vi thit k thu lc cu;

V tr ca im vt sng c triu cn xt n dng sng c thng, un khc, quanh co hoc

chuyn tip khng, hoc c thit b kim tra bo v cu trong iu kin hin ti hoc lng trc

trong tng lai khng;

Hiu ng ca bt k nhng thay i dng d kin;

Hiu ng ca vic khai thc ct v cc hot ng khc trn dng sng;

Nhng thay i tim tng v tc v lu lng nc do nhng thay i v s dng t;

Hiu ng ca nhng thay i v phn b dng theo a mo t nhin ln kt cu kin ngh; v

Hiu ng ca nhng thay i a mo ln cng trnh hin c vng ph cn v gy ra bi kt cu

d kin.

i vi iu kin sng hoc dng khng n nh phi tin hnh nhng nghin cu c bit xc nh

nhng thay i c th trong tng lai v mt bng v mt ct sng v xc nh cc bin php khc phc

lin quan trong thit k hoc trong tng lai v s an ton ca cu v ng u cu.

2.6.4.3. Khu cu

Qu trnh thit k xc nh khu cu phi bao gm:

nh gi s phn b ca l dng ch v b^i sng cho iu kin hin ti,

nh gi cc t hp th ca mt ct ng, hng tuyn v chiu di cn p ng vi cc mc tiu

thit k.

Khi dng cc nghin cu v l hin c th phi xc nh chnh xc ca chng .

Phi thit k kch thc cu ph hp vi l thit k khu cu ng vi l 100 nm, tr khi c Ch

u t ch nh khc. C th chn chu k ti xut hin t hn 100 nm nu c lun c kinh t (nh l 50

nm hoc 25 nm cho cc cu trn ng cp 2 hoc cp thp hn tham kho Bng 10.5.1 trong Tiu

chun thit k ng).


Kh gii hn ti thiu theo chiu thng ng ca kt cu trn mc nc tng ng vi l thit k khu

phi ly nh sau:

n mt di y ca kt cu phn trn:

Trong trng hp dng l c mang theo s lng ln cc vt tri hay bn : ............................1,0m

Cc trng hp khc :.................................................................................................................. 0,5m

n tm k gi: ......................................................................................................................0,25m

n cao ca mi cng trnh iu tit dng sng:.................................................................0,5m

2.6.4.4. Mng cu

2.6.4.4.1. Tng qut

Nhng vn v kt cu, thu lc v a k thut ca thit k mng phi c phi hp v phn bit

gii quyt trc khi duyt thit k s b.

2.6.4.4.2. Xi l cu

Nh cc yu cu iu 3.7.5, xi mng cu c nghin cu cho 2 iu kin:

L thit k xi: Vt liu y sng trong lng th xi pha trn ng xi chung c gi nh l

^ c chuyn i trong cc iu kin thit k. L thit k do ma km triu dng hoc l hn hp

thng nghim trng hn l l 100 nm hoc l trn vi chu k ti xut hin nh hn. Cc trng

thi gii hn cng v trng thI gii s dng phi p dng cho iu kin ny.

L kim tra xi: n nh mng cu phi c nghin cu i vi cc iu kin xi gy ra do l

dng t xut v b^o ma km triu dng, hoc l hn hp khng vt qu l 500 nm hoc l trn

vi chu k ti xut hin nh hn. D tr vt qu yu cu v n nh trong iu kin ny l khng

cn thit. Phi p dng trng thi gii hn c bit cho iu kin ny.

Nu iu kin ti ch do tch rc v dnh nc gn ni hp lu i hi phi dng l s c ln hn

thay cho l thit k xi hoc l kim tra xi th ngi thit k c th dng l s c .

Mng m rng t trn nn t hoc d xi th y ca n cn t di su xi do l kim tra

xi gy nn. Mng m rng t trn nn khng b xi phi c thit k v thi cng m bo tnh

ton vn ca khi chu lc.


B mng nn c thit k vi nh b thp hn mc xi chung tnh ton gim thiu tr ngi cho

dng l v dn n xi cc b. Ngay c su thp hn cng cn c xt cho b mng t trn cc

m cc cc c th b ph hoi do xi v g v ph ra trc dng chy.

Ti nhng ni buc phi b tr nh b cc cao hn y sng cn ch n xi tim tng trong

thit k.

Khi dng tr chng va hoc h thng bo v tr khc th trong thit k cn xt n hiu ng ln xi tr

cu v s tch rc.

n nh ca m trong vng c dng chy xoy cn c nghin cu k v mi dc nn p nh ra

phi c bo v vi cc bin php chng xi ph hp.

2.6.4.5. ng u cu

Thit k cu cn phi hp vi thit k ng hai u cu bî sng sao cho ton b m hnh dng chy

c pht trin v phn tch nh mt thc th thng nht v lin quan ln nhau.

Ni nn ng trn bî sng cn tr l vt qua th on ny cn c thit k gim thiu cc ri ro

ca l.

ni xy ra s chy chch sang mt dng khc do nc chy ngc v chng ngi trn dng chy gy ra, phi tin hnh nh gi li thit k m bo cc yu cu php l i vi ri ro do l dng

nc khc ny.

2.6.5. V tr, chiu di v khu cng

Ngoi cc quy nh ca iu 2.6.3 v 2.6.4 , cn xem xt:cc iu kin sau y:

C v mung th qua li;

Hiu ng ca tc cao ca ra v dng tp trung i vi ca ra, lng h lu v ti sn lin quan;

Hiu ng ni ca vo;

An ton giao thng;

Hiu ng ca nc dnh ngc, c th gy ra bi cc cng trnh chnh tr sng pha h lu hoc

thu triu lc c bô.

2.6.6. Thot nc mt

2.6.6.1. Tng qut

Mt cu v ng u cu cn phi c thit k m bo thot nc mt an ton v hu hiu sao

cho t h hi nht i vi cu v an ton ti a cho xe c i li. Mt cu, bao gm mt ng, ng xe

p v ng ngi i b phi c lm c dc ngang hoc siu cao thot nc tt theo hng


ngang. Vi cc cu rng mi hng c trn 3 ln xe c th phi thit k c bit cho thot nc mt cu

v/hoc c th phi dng mt ng nhm c bit gim kh nng xe b quay trt do mt ma st.

Nc chy xung r^nh ng cn c chn li khng cho chy vo cu. R^nh thot nc u cu

cn phi c kh nng thot ton b nc c gom li.

Trong nhng trng hp rt nhy cm v mi trng m khng th x nc trc tip t mt cuxung

sng pha di cn xt n giI php dn nc theo ng ng thot nc dc gn pha di kt cu

nhp cu v x vo ni ph hp trn mt t t nhin u cu.

2.6.6.2. Lng ma thit k

Lng ma thit k cho thot nc mt cu khng c nh hn lng ma thit k cho thot nc mt

ng u cu, tr khi Ch u t c quy nh khc.

2.6.6.3. Loi hnh, kch thc v s lng ng thot nc

S lng ng thot nc cn gi mc ti thiu ph hp vi cc yu cu thu lc.

Khi thiu cc ch dn thc hnh khc, i vi cu m tc xe thit k trn ng nh hn 75km/gi

th kch thc v s lng ng thot nc cn m bo nc khng ngp qua mt na chiu rng ca

bt k ln xe no. i vi cu m tc xe thit k trn ng khng nh hn 75km/gi cn m bo

nc khng ngp bt k b phn no ca ln xe. R^nh cn c chn li ch thay i dc trnh

nc chy qua mt cu. Din tch mt ct ngang ti thiu ca ng thot nc phi ly l 1cm2 trn 1m2

mt cu. C ly ti a gia cc ng thot nc dc cu khng c vt qu 15m.

L thot nc hoc h thu nc ca mt cu phi thot nc v d lm sch. Kch thc bn

trong ti thiu ca ng thot nc thng thng khng c t hn 100mm

2.6.6.4. X nc t ng thot nc mt cu

ng thot nc mt cu phi c thit k v lp t sao cho nc t mt cu hoc mt ng c dn

ra xa khi cc cu kin ca kt cu phn trn v kt cu phn di.

Nu Ch u t khng c i hi c bit kim tra nc thot ra t ng thot nc v ng ng th

cn xt n:

t nht ng phi nh ra khi cu kin thp nht ca kt cu phn trn l 100mm,

t ng thot nc c ming loe 450 x nc khng ri vo cu kin cu,


ch c th v c php c th th cho nc chy t do hoc qua ca thot nc trn ng

ngi i;

Dng cc ct ni c gc khng ln hn 450; v

Dng cc ng thng.

Nc chy t mt cu cn c b tr ph hp vi cc i hi v mi trng v an ton giao thng.

2.6.6.5. Thot nc kt cu

Cc h thu nc trong kt cu ni cn c phi t im thp nht. Mt cu v mt ng cn thit

k trnh ng nc nht l nhng khe ni mt cu. i vi mt cu c mt khng nguyn khi hoc

c vn khun li cn xt thot phn nc c th ng mt tip gip.


Phn 3 - Ti trng v h s ti trng

3.1. Phm vi

Trong phn ny quy nh nhng yu cu ti thiu i vi ti trng v lc, phm vi p dng ca

chng, cc h s ti trng v t hp ti trng dng trong thit k cc cu mi. Nhng quy nh v

ti trng cng c dng trong nh gi kt cu cc cu ang khai thc.

ch no c nhiu mc lm vic khc nhau, vic la chn mc lm vic thit k l trch nhim ca Ch u t.

Mt h s ti trng ti thiu c quy nh xc nh cc ng lc c th pht sinh trong qu

trnh thi cng. Cc yu cu b sung cho vic xy dng cc cu b tng thi cng phn on c

quy nh trong iu 5.14.2.

3.2. Cc nh ngha

p lc t ch ng - p lc ngang gy ra do t c kt cu hay b phn kt cu chn li. p lc ny c xu hng lm chuyn dch kt cu chn ri khi khi t.

Lng th t ch ng - Lng th t c xu hng chuyn dch nu khng c kt cu hay b

phn kt cu chn gi li.

Dao ng kh ng n hi - Phn ng n hi theo chu k ca kt cu di tc ng ca gi.

n v trc xe - Trc n hay trc i (tandem) ca xe

H o - Cng trnh bng t dng nh hng li hoc lm chm li s va x ca xe c hoc

tu thuyn v n nh t p, nn ng hoc t yu v cc ta luy o.

Lc ly tm - Lc ngang do xe chuyn hng di ng trn ng cong.

Ln xe thit k - Ln xe quy c t theo chiu ngang trn b rng phn xe chy.

Chiu su nc thit k - Chiu su ca nc mc nc cao trung bnh.

Bin hnh - Thay i hnh hc ca kt cu.

- Vt th phng h, c th c h thng chn ring, thng c mt trn v c lp v kt cu vi cu.

Lc xung kch - Phn tng thm lc tnh xt n tng tc ng gia cu v xe c i li.


Cht lng tng ng - L mt cht quy c c t trng c th gy ra cng p lc nh t c thay th tnh ton.

Phn l ra - iu kin trong c mt b phn ca kt cu phn di hay phn trn ca cu c th b va chm bi bt k b phn no ca mi tu, ca bin hay ct tu.

Cc hn - Ti a hay ti thiu.

Vt chn chng va - Kt cu phng h cng c lin kt vo b phn kt cu c bo v hoc dn lung hoc chuyn hng cc tu b chch hng.

Tng th - Ph hp vi ton b kt cu phn trn hay ton b cu.

Ti trng thng xuyn - Ti trng v lc khng i hoc gi thit khng i sau khi hon thnh vic xy dng.

Mt nh hng - Mt b mt lin tc hay ri rc c v ng vi cao mt cu trong m hnh tnh ton m gi tr ti mt im ca n nhn vi ti trng tc dng thng gc vi mt cu ti im s c ng lc.

Quy tc n by - Ly tng m men i vi mt im tm phn lc ti im th hai.

Ho lng - S mt cng chu ct trong t b_o ho do vt qua p lc thu tnh. Trong t ri b_o ho, s mt cng ny c th do ti trng tc thi hoc chu k, c bit trong ct nh n ct va ri rc ht ng nht.

Ti trng - Hiu ng ca gia tc bao gm gia tc trng trng, bin dng cng bc hay thay i th tch.

Cc b - Tnh cht c lin quan vi mt cu kin hoc cm lp rp ca cu kin.

Tn (Megagram (Mg) - 1000 kg (mt n v khi lng).

Dng thc dao ng - Mt dng ca bin dng ng ng vi mt tn sut dao ng.

ng thu thng thng - Mt ng thu c xp hng thng thng bi Cc ng sng Vit Nam hoc Cc Hng hi Vit Nam.

Ti trng danh nh - Mc ti trng thit k c la chn theo quy c.

t c kt thng thng - t di p lc t ph ln hn p lc t _ tng hin din trong qu kh ch ang xt.

t qu c kt - t di p lc t ph hin nay m nh hn p lc t ph _ tng c trong qu kh.

T l qu c kt - t phd lc p

nht ln kt c lc pOCR =

p lc t b ng - p lc ngang do t chng li chuyn v ngang v pha khi t ca kt cu hoc b phn kt cu.

Xe c php - Xe bt k c php i l xe b hn ch mt cch no v trng lng hoc v

kch thc ca chng.


Ch s tin cy - S nh ga bng s lng v mt an ton nh l t s ca chnh lch gia sc

khng bnh qun v ng lc bnh qun vi lch- Tiu chun t hp ca sc khng v ng lc.

B rng lng ng, B rng phn xe chy - Khong cch tnh gia ro chn v/ hoc va.

Nhit lp t - Nhit trung bnh ca kt cu dng xc nh kch thc ca kt cu khi

lp thm mt cu kin hoc khi lp t.

Ro chn lin tc v kt cu - Ro chn hoc bt k b phn no ca n ch ngt khe ch ni

mt cu.

Kt cu phn di - B phn kt cu cu kt cu nhp bn trn.

Kt cu phn trn - B phn kt cu cu vt nhp (kt cu nhp).

Ti trng cht thm - Ti trng c dng m hnh ho trng lng t p hoc cc ti trng

khc tc dng trn nh ca vt liu chn gi.

Xe ti trc - Xe c hai trc t st nhau, thng c lin kt vi mt khung gm xe phn b

ti trng u nhau.

Gc ma st tng - Gc c arctg th hin ma st biu kin gia tng v khi t.

Bnh xe - Mt hoc hai bnh lp u mt trc xe.

Dy bnh xe - Mt nhm bnh xe c xp theo chiu ngang hoc chiu dc.

3.3. K hiu

3.3.1. Tng qut A = h s gia tc ng t (3.10.2)

At = din tch ca kt cu hoc cu kin tnh p lc gi ngang (m3) (3.8.1.2.1)

Av = din tch mt ca mt cu hoc cu kin tnh p lc gi thng ng (m2) (3.8.2)

aB = chiu di h hng mi s lan ch hng tiu chun (mm) (3.14.8)

as = chiu rng h hng ca mi tu (mm) (3.14.6)

BR = lc h_m xe

b = h s lc h_m; Tng chiu rng cu (mm) (3.3.2) (3.8.1.2.1)

C = h s dng tnh lc ly tm (3.6.3)

CD = h s cn (S2N/mm4 (3.7.3.1)

CH = h s thu ng hc khi lng (3.14.4)

CL = h s cn ngang (3.7.3.2)

Cd = h s cn (S2N/mm4) (3.8.1.2.1)

Cn = h s vt mi tnh Fb (3.9.2.2)

Csm = h s p ng ng t n hi cho dng thc dao ng th m (3.10.6.1)

c = dnh kt n v (MPa) (3.11.5.4).


DE = chiu dy ti thiu ca lp t ph (mm) (3.6.2.2) DWT = kch c tu da trn tn trng ti (Mg) (3.14.2). d = chiu cao kt cu phn trn (mm) (3.8.1.2.1) g = gia tc trng trng (m/s2) (3.6.3) H = chiu cao cui cng ca tng chn (mm) (3.11.5.1) HL = chiu cao ca khi u s lan ti mi ca n (mm) (3.14.11.1) h = chiu cao danh nh ca s p lc t (mm) (3.11.5.7) heq = chiu cao tng ng ca t do ti trng xe (mm) (3.11.6.2) IM = lc xung kch (3.6.1.2.5) KE = nng lng va tu thit k (joule) (3.14.4) k = h s p lc t (3.11.6.2) ka = h s p lc t ngang ch ng (3.11.5.1) kh = h s p lc t ngang (3.11.5.1) k0 = h s p lc t ngang trng thi ngh (3.11.5.1) kp = h s p lc b ng (3.11.5.4) ks = h s p lc t do hot ti (3.11.6.1) LOA = tng chiu di ca tu hoc s lan lai bao gm tu y hoc ko (mm) (3.14.2) M = khi lng ca tu (Mg) (3.14.4) m = h s ln (3.6.1.1.2) OCR = t s qu c kt (3.11.5.2) P = ti trng bnh xe tp trung (N); ti trng (N) (3.6.1.2.5) (3.11.6.1) Pa = p lc t biu kin (MPa); hp lc trn n v b rng tng (N/mm)

(3.11.5.6) (3.11.5.7) PB = lc va s lan do m u vo nhau gia mi s lan v vt cng (N) (3.14.8) PBH = lc va tu gia mi tu v kt cu phn trn cng (N) (3.14.7.1) PD = ti trng gi ngang (KN) (3.8.2.1) PDH = lc va tu gia ca bin tu v kt cu phn trn cng (N) (3.14.7.2). Ph = thnh phn nm ngang ca lc trn n v chiu di tng do p lc t (N/mm) (3.11.5.5) PMT = lc va tu gia ct tu v kt cu phn trn cng (N) (3.14.7) PN = thnh phn thng ng ca p lc gi (MPa) (3.8.1.4) Pp = p lc t b ng (MPa) (3.11.5.4) PS = lc va tu do m u vo nhau gia mi tu v vt cng (N) (3.14.5) Pv = lc gi thng ng (KN); thnh phn thng ng ca lc trn n v chiu di tng do p lc t (N/mm) (3.8.2) (3.11.5.5) p = p lc dng chy (MPa); p lc t c bn (MPa) phn ca xe ti trong ln n; cng ti trng(MPa)(3.7.3.1)(3.11.5.1)(3.6.1.4.2)(3.11.6.1) Q = cng ti trng (N/mm) (3.11.6.1)

q = ti trng ni chung (3.4.1)

qs = hot ti tc dng ln nht (MPa)(3.11.6.1)

R = bn knh cong (mm); bn knh ca tr trn (mm); h s iu chnh p ng

ng t, c ly tia t im t ti ti mt im trn tng (3.6.3) (3.9.5)

(3.10.7.1) (3.11.6.1).

RBH = t s ca chiu cao kt cu phn trn l ra trn tng chiu cao mi tu (3.14.7.1)

RDH = h s chit gim lc va ca bin tu (3.14.7.2)

S = h s iu chnh i vi a hnh v chiu cao mt cu; h s lin quan

n iu kin ti ch xc nh ti trng ng t (3.8.1.1) (3.5.10)

Tm = chu k dao ng hng th m(s) (3.10.6.1)

t = chiu dy bn mt cu (mm) (3.12.3) V = vn tc nc thit k (m/s); vn tc gi thit k (m/s); tc va tu thit

k (m/s) (3.7.3.1)(3.8.1.1)(3.14.3)


VB = vn tc gi c bn (m/s) (3.8.1.1)

v = tc thit k ng t (m/s)(3.6.3)

w = chiu rng tnh ca lng ng (mm)(3.6.1.1.1)

X = c ly ngang t lng tng n im t lc(mm)(3.11.6.1)

X1 = c ly t lng tng n im u ca tuyn ti trng (3.11.6.1)

X2 = chiu di hot ti (mm) (3.11.6.1)

Z = chiu cao di mt t (mm); chiu cao t mt t n mt im trn tng ang xem xt (mm); c ly thng ng t im t lc ti cao im trn tng ang xem xt (mm) (3.11.5.4)(3.11.6.1)

z = chiu su di mt t p (mm)(3.11.5.1)

= gc gia tng mng v ng ni im ang xem xt trn tng v im

gc y b xa tng nht ( rad) (3.11.6.1)

B = mi dc tng trng ca t lp () (3.11.5.7)

= ch s an ton; dc ca mt t lp pha sau tng chn () (3.4.1)(3.11.5.3)

= t trng ca vt liu ( kg/m3); t trng ca t (kg/m3) (3.5.1)(3.11.5.1)

s = t trng hu hiu ca t (kg/m3)(3.11.5.6)

EQ = h s ti trng i vi hot ti tc dng ng thi vi ti trng ng t (3.4.1)

eq = t trng tng ng cht lng (kg/m3)(3.11.5.5)

1 = h s ti trng (3.4.1)

p = h s ti trng cho ti trng thng xuyn (3.4.1)

SE = h s ti trng cho ln (3.4.1)

TG = h s ti trng cho gradien nhit (3.4.1)

p = p lc t ngang khng i do hot ti ri u (MPa)(3.11.6.1)

ph = phn b p lc ngang (MPa) (3.11.6.1)

= gc ma st gia t lp v tng (); gc gia tng mng v ng ni

im ang xem xt trn tng v im gc y b gn tng nht (rad) (3.11.5.3) (3.11.6.1)

= iu chnh ti trng quy nh trong iu 1.3.2 (3.4.1)

= gc ca hng gi (); gc ca t lp tng so vi trc ng (); gc

gia hng dng chy vi trc dc ca tr ()(3.8.1.4)(3.11.5.3)(3.7.3.2)

v = h s Poisson (DIM) (3.11.6.1)(3.11.5.3)

= h s sc khng (3.4.1)

t = gc ma st ni ca t thot nc ()(3.11.5.2)

= gc ma st ni c hiu() (3.11.5.3)

3.3.2. Ti trng v tn ti trng Cc ti trng v lc thng xuyn v nht thi sau y phi c xem xt n:

Ti trng thng xuyn DD = ti trng ko xung (xt hin tng ma st m) DC = ti trng bn thn ca cc b phn kt cu v thit b ph phi kt cu DW = ti trng bn thn ca lp ph mt v cc tin ch cng cng EH = ti trng p lc t nm ngang EL = cc hiu ng b h_m tch lu do phng php thi cng. ES = ti trng t cht thm EV = p lc thng ng do t trng t p.

Ti trng nht thi


BR = lc h_m xe CE = lc ly tm CR = t bin CT = lc va xe CV = lc va tu EQ = ng t FR = ma st IM = lc xung kch (lc ng ) ca xe LL = hot ti xe LS = hot ti cht thm PL = ti trng ngi i SE = ln SH = co ngt TG = gradien nhit TU = nhit u WA = ti trng nc v p lc dng chy WL = gi trn hot ti WS = ti trng gi trn kt cu

3.4. Cc h s v t hp ti trng

3.4.1. H s ti trng v t hp ti trng

Tng ng lc tnh ton phi c ly nh sau:

iii QQ = (3.4.1-1) trong :

i = h s iu chnh ti trng ly theo iu 1.3.2

Qi = ti trng quy nh y

i = h s ti trng ly theo Bng 1 v 2

Cc cu kin v cc lin kt ca cu phi tho m_n phng trnh 1.3.2.1.1 cho cc t hp thch hp ca ng lc cc hn tnh ton c quy nh cho tng trng thi gii hn sau y:

Trng thi gii hn cng i: T hp ti trng c bn lin quan n vic s dng cho xe tiu chun ca cu khng xt n gi

Trng thi gii hn cng ii: T hp ti trng lin quan n cu chu gi vi vn tc vt qu 25m/s

Trng thi gii hn cng iii: T hp ti trng lin quan n vic s dng xe tiu chun ca cu vi gi c vn tc 25m/s

Trng thi gii hn c bit: T hp ti trng lin quan n ng t, lc va ca tu thuyn v xe c, v n mt s hin tng thu lc vi hot ti _ chit gim khc vi khi l mt phn ca ti trng xe va x, CT.

Trng thi gii hn s dng: T hp ti trng lin quan n khai thc bnh thng ca cu vi gi c vn tc 25m/s vi tt c ti trng ly theo gi tr danh nh. Dng kim tra

vng, b rng vt nt trong kt cu b tng ct thp v b tng ct thp d ng lc, s chy do ca

kt cu thp v trt ca cc lin kt c nguy c trt do tc dng ca hot ti xe. T hp trng ti

ny cng cn c dng kho st n nh mi dc.


Trng thi gii hn mi: T hp ti trng gy mi v t gy lin quan n hot ti xe c

trng phc v xung kch di tc dng ca mt xe ti n chic c c ly trc c quy nh trong

iu 3.6.1.4.1.

H s ti trng cho cc ti trng khc nhau bao gm trong mt t hp ti trng thit k c ly nh

quy nh trong Bng 1. Mi tp hp con tho ng ca cc t hp ti trng phi c nghin cu. C

th nghin cu thm cc t hp ti trng khc khi ch u t yu cu hoc ngi thit k xt thy cn

thit. i vi mi t hp ti trng, mi ti trng c a vo tnh ton v c lin quan n cu kin

c thit k bao gm c cc hiu ng ng k do tc dng ca xon, phi c nhn vi h s ti

trng tng ng vi h s ln ly theo iu 3.6.1.1.2 nu c th p dng. Kt qu c tng hp theo

phng trnh 1.3.2.1-1 v nhn vi h s iu chnh ti trng ly theo iu 1.3.2.

Cc h s phi chn sao cho gy ra tng ng lc tnh ton cc hn. i vi mi t hp ti trng c

tr s cc hn m ln tr s cc hn dng u phi c xem xt.

Trong t hp ti trng nu tc dng ca mt ti trng lm gim tc dng ca mt ti trng khc th phi

ly gi tr nh nht ca ti trng lm gim gi tr ti trng kia. i vi tc ng ca ti trng thng

xuyn th h s ti trng gy ra t hp bt li hn phi c la chn theo Bng 2. Khi ti trng thng

xuyn lm tng s n nh hoc tng nng lc chu ti ca mt cu kin hoc ca ton cu th tr s ti

thiu ca h s ti trng i vi ti trng thng xuyn ny cng phi c xem xt.

Tr s ln hn ca hai tr s quy nh cho h s ti trng TU, CR, SH s c dng tnh bin

dng, cn tr s nh hn dng cho cc tc ng khc.

Khi nh gi n nh tng th ca mi t c mng hoc khng c mng u cn kho st trng

thi gii hn s dng da trn t hp ti trng s dng v mt h s sc khng ph hp. Nu

khng c cc thng tin tt hn th h s sc khng c th ly nh sau:

Khi cc thng s a k thut c xc nh tt v mi dc khng chng hoc khng cha

cu kin ..................................................................................................................................0,85

Khi cc thng s a k thut da trn thng tin cha y hay cha chnh xc hoc mi dc

c cha hoc chng mt cu kin ....................................................................................0,65.

i vi cc kt cu hp dng bn ph hp vi cc quy nh ca iu 12.9, h s hot ti i vi hot

ti xe LL v IM ly bng 2,0.


Bng 3.4.1-1- T hp v h s ti trng

Cng mt lc ch dng mt trong cc

ti trng

T hp ti trng

Trng thi gii hn

DC DD DW EH EV ES

LL IM CE BR PL LS EL

WA

WS

WL

FR

TU CR SH

TG

SE

eq ct cv

Cng I n 1,75 1,00 - - 1,00 0,5/1.20 TG SE - - - Cng II n - 1,00 1,40 - 1,00 0,5/1.20 TG SE - - - Cng III n 1,35 1,00 0.4 1,00 1,00 0,5/1.20 TG SE - - - c bit n 0,50 1,00 - - 1,00 - - - 1,00 1,00 1,00 S dng 1.0 1,00 1,00 0,30 1,00 1,00 1,0/1,20 TG SE - - - Mi ch c LL, IM & CE - 0,75 - - - - - - - - - -

Ghi ch bng 3.4.1-1:

1. Khi phi kim tra cu dng cho xe c bit do Ch u t quy nh hoc xe c giy php thng

qua cu th h s ti trng ca hot ti trong t hp cng I c th gim xung cn 1,35.

2. Cc cu c t l tnh ti trn hot ti rt cao (tc l cu nhp ln) cn kim tra t hp khng c

hot ti, nhng vi h s ti trng bng 1,50 cho tt c cc kin chu ti trng thng xuyn.

3. i vi cu vt sng cc trng thi gii hn cng v trng thi s dng phi xt n

hu qu ca nhng thay i v mng do l thit k xi cu.

4. i vi cc cu vt sng, khi kim tra cc hiu ng ti EQ, CT v CV trng thi gii hn

c bit th ti trng nc (WA) v chiu su xi c th da trn l trung bnh hng nm. Tuy

nhin kt cu phi c kim tra v v nhng hu qu do cc thay i do l, phi kim tra xi

nhng trng thi gii hn c bit vi ti trng nc tng ng (WA) nhng khng c cc ti

trng EQ, CT hoc CV tc dng.

5. kim tra chiu rng vt nt trong kt cu b tng ct thp d ng lc trng thi gii hn

s dng, c th gim h s ti trng ca hot ti xung 0,80.

6. kim tra kt cu thp trng thi gii hn s dng th h s ti trng ca hot ti phi

tng ln 1,30.


Bng 3.4.1-2 - H s ti trng dng cho ti trng thng xuyn, p

H s ti trng Loi ti trng

Ln nht Nh nht DC: Cu kin v cc thit b ph 1,25 0,90 DD: ko xung (xt ma st m) 1,80 0,45 DW: Lp ph mt cu v cc tin ch 1,50 0,65 EH: p lc ngang ca t Ch ng Ngh

1,50 1,35

0,90 0,90

EL: Cc ng sut lp rp b hm 1,00 1,00 EV: p lc t thng ng n nh tng th Kt cu tng chn Kt cu vi cng Khung cng Kt cu vi mm khc vi cng hp thp Cng hp thp mm

1,35 1,35 1,30 1,35 1,95 1,50

N/A 1,00 0,90 0,90 0,90 0,90

ES: Ti trng t cht thm 1,50 0,75

H s ti trng tnh cho gradien nhit TG v ln

SE cn c xc nh trn c s mt n c

th ring. Nu khng c thng tin ring c th ly TG bng:

0,0 cc trng thi gii hn cng v c bit

1,0 trng thi gii hn s dng khi khng xt hot ti, v

0,50 trng thi gii hn s dng khi xt hot ti

i vi cu thi cng phn on, phi xem xt t hp sau y trng thi gii hn s dng:

DC + DW + EH + EV + ES + WA + CR + SH + TG + EL (3.4.1-2)

3.4.2. H s ti trng dng cho ti trng thi cng

H s ti trng dng cho ti trng kt cu v cc ph kin khng c ly nh hn 1,25.

Tr khi c quy nh khc ca Ch u t, h s ti trng cho ti trng thi cng cho cc thit b v

cc tc ng xung kch khng c ly nh hn 1,5. H s ti trng gi khng c ly nh hn

1,25. H s ca cc ti trng khc phi ly bng 1,0.

3.4.3. H s ti trng dng cho lc kch nng h kt cu nhp v lc ko sau i vi cp d ng lc

3.4.31. Lc kch

Tr khi c quy nh khc ca Ch u t, lc kch thit k trong khai thc khng c nh hn 1,3

ln phn lc gi lin k vi im kch do ti trng thng xuyn.

Khi kch dm m khng ngng giao thng th lc kch cn phi xt n phn lc do hot ti ph

hp vi k hoch duy tr giao thng nhn vi h s ti trng i vi hot ti.

3.4.3.2. Lc i vi vng neo ko sau

Lc thit k i vi vng neo ko sau phi ly bng 1,2 ln lc kch ln nht.


3.5. Ti trng thng xuyn

3.5.1. Tnh ti DC, DW v EV

Tnh ti bao gm trng lng ca tt c cu kin ca kt cu, ph kin v tin ch cng cng km

theo, trng lng t ph, trng lng mt cu, d phng ph b v m rng.

Khi khng c s liu chnh xc c th ly t trng nh Bng 1 tnh tnh ti

Bng 3.5.1-1- T trng

Vt liu T trng (kg/m3) Hp kim nhm 2800 Lp ph b tng at-phan 2250 X than 960 Ct cht. ph sa hay t st 1925

Nh 1775 Ct nh 1925

B tng

Thng 2400 Ct ri. ph sa. si 1600 t st mm 1600 Si. cui. macadam hoc balat 2250 Thp 7850 xy 2725

Ngt 1000 Nc Mn 1025

3.5.2. Ti trng t EH, ES v DD

p lc t, ti trng ph gia trn t , ti trng ko xung (ma st m) c xc nh trong iu 3.11.

3.6. hot ti

3.6.1. Ti trng trng lc: LL v PL

3.6.1.1. Hot ti xe

3.6.1.1.1. S ln xe thit k

S ln xe thit k c xc nh bi phn s nguyn ca t s w/3500, y w l b rng khong

trngca lng ng gia hai va hoc hai ro chn, n v l mm. Cn xt n kh nng thay i

trong tng lai v vt l hoc chc nng ca b rng trng ca lng ng ca cu .

Trong trng hp b rng ln xe nh hn 3500mm th s ln xe thit k ly bng s ln giao thng v

b rng ln xe thit k phi ly bng b rng ln giao thng.


Lng ng rng t 6000mm n 7200mm phi c 2 ln xe thit k, mi ln bng mt na b rng

lng ng.

3.6.1.1.2. H s ln xe

Nhng quy nh ca iu ny khng c p dng cho trng thi gii hn mi, trong trng hp

ch dng vi mt xe ti thit k, bt k s ln xe thit k. Khi dng h s phn phi gn ng ca 1 ln

xe n nh trong iu 4.6.2.2. v 4.6.2.3, khc vi quy tc n by v phng php tnh hc, ng lc

phi c chia cho 1,20.

ng lc cc hn ca hot ti phi xc nh bng cch xt mi t hp c th ca s ln chu ti nhn vi h s tng ng trong Bng 1.

H s trong Bng 3.6.1.1.2.1 khng c p dng kt hp vi h s phn b ti trng gn ng quy

nh trong iu 4.6.2.2 v 4.6.2.3, tr khi dng quy tc n by hay khi c yu cu ring cho dm

ngoi cng trong cu dm- bn quy nh trong iu 6.2.2.2.d th c p dng

Bng 3.6.1.1.2.1- H s ln m

S ln cht ti H s ln (m)

1 1,20 2 1,00 3 0,85

> 3 0,65

3.6.1.2. Hot ti xe t thit k

3.6.1.2.1. Tng qut

Hot ti xe t trn mt cu hay kt cu ph tr c t tn l HL-93 s gm mt t hp ca:

Xe ti thit k hoc xe 2 trc thit k, v

Ti trng ln thit k

Tr trng hp c iu chnh trong iu 3.6.1.3.1, mi ln thit k c xem xt phi c b tr

hoc xe ti thit k hoc xe hai trc chng vi ti trng ln khi p dng c. Ti trng c gi thit

chim 3000mm theo chiu ngang trong mt ln xe thit k.

3.6.1.2.2. Xe ti thit k

Trng lng v khong cch cc trc v bnh xe ca xe ti thit k phi ly theo Hnh 3.6.1.2.2-1. Lc

xung kch ly theo iu 3.6.2

Tr quy nh trong iu 3.6.1.3.1 v 3.6.1.4.1, c ly gia 2 trc 145.000N phi thay i gia 4300 v

9000mm gy ra ng lc ln nht.

i vi cc cu trn cc tuyn ng cp IV v thp hn, Ch u t c th xc nh ti trng trc cho

trong Hnh 3.6.1.2.2-1 nhn vi h s 0,50 hoc 0,65.


-

35 kN 145 kN 145 kN 4300 mm 4300 mm ti 9000mm

600 mm ni chung

300mm mt tha ca mt cu

Ln thit k 3500 mm

Hnh 3.6.1.2.2-1 - c trng ca xe ti thit k

3.6.1.2.3. Xe hai trc thit k

Xe hai trc gm mt cp trc 110.000N cch nhau 1200mm. C ly chiu ngang ca cc bnh xe ly

bng 1800mm. Ti trng ng cho php ly theo iu 3.6.2.

i vi cc cu trn cc tuyn ng cp V v thp hn, Ch u t c th xc nh ti trng xe hai

trc ni trn nhn vi h s 0,50 hoc 0,65.

3.6.1.2.4. Ti trng ln thit k

Ti trng ln thit k gm ti trng 9,3N/mm phn b u theo chiu dc. Theo chiu ngang cu c gi

thit l phn b u trn chiu rng 3000mm. ng lc ca ti trng ln thit k khng xt lc xung kch.

3.6.1.2.5. Din tch tip xc ca lp xe

Din tch tip xc ca lp xe ca mt bnh xe c mt hay hai lp c gi thit l mt hnh ch nht c

chiu rng l 510mm v chiu di tnh bng mm ly nh sau:

L = 2,28 x 10-3 (1 + lM/100)P (3.6.1.2.5-1)

trong : = h s ti trng

lM = lc xung kch tnh bng phn trm

P = 72500 N cho xe ti thit k v 55000N cho xe hai trc thit k.

p lc lp xe c gi thit l phn b u trn din tch tip xc. p lc lp xe gi thit phn b nh sau:


Trn b mt lin tc phn b u trn din tch tip xc quy nh

Trn b mt b gin on phn b u trn din tch tip xc thc t trong phm vi vt xe vi p sut tng theo t s ca din tch quy nh trn din tch tip xc thc t.

3.6.1.2.6. Phn b ti trng bnh xe qua t p

Khi b dy lp t p nh hn 600mm th c th b qua nh hng ca t p n s phn b ti trng bnh xe. S phn b hot ti ln nh cng c th ly theo quy nh trong iu 4.6.2.1 v 4.6.3.2 cho bn mt cu bc song song vi chiu xe chy.

Thay cho vic phn tch chnh xc hn hoc dng cc phng php gn ng c chp nhn khc v phn b ti trng c quy nh trong Phn 12, khi b dy t p ln hn 600mm, ti trng bnh xe c th c coi l phn b u trn mt hnh ch nht c cnh ly bng kch thc vng tip xc ca lp quy nh trong iu 3.6.1.2.5 v tng ln hoc 1,15 ln b dy lp ph bng cp phi chn lc, hoc bng b dy lp ph trong cc trng hp khc. Phi p dng nhng quy nh trong cc iu 3.6.1.1.2 v 3.6.1.3

Khi cc vng phn b ca nhiu bnh xe chp vo nhau th tng ti trng phi c phn b u trn din tch.

i vi cng mt nhp khi chiu dy lp t p ln hn 2400mm v ln hn chiu di nhp th c th b qua tc dng ca hot ti; i vi cng nhiu nhp c th b qua tc dng ca hot ti khi b dy t p ln hn khong cch gia b mt ca cc tng u ca cng.

Khi m men trong bn b tng do hot ti v lc xung kch da trn s phn b ca ti trng bnh xe qua t p ln hn m men do hot ti v lc xung kch c tnh theo iu 4.6.2.1 v 4.6.3.2 th phi dng m men trong trng hp sau.

3.6.1.3. Tc dng ca hot ti xe thit k

3.6.1.3.1. Tng qut

Tr khi c quy nh khc, ng lc ln nht phi c ly theo gi tr ln hn ca cc trng hp sau:

Hiu ng ca xe hai trc thit k t hp vi hiu ng ti trng ln thit k , hoc

Hiu ng ca mt xe ti thit k c c ly trc bnh thay i nh trong iu 3.6.1.2.2 t hp vi

hiu ng ca ti trng ln thit k, v

i vi m men m gia cc im un ngc chiu khi chu ti trng ri u trn cc nhp v ch i vi phn lc gi gia th ly 90% hiu ng ca hai xe ti thit k c khong cch trc bnh trc xe ny cch bnh sau xe kia l 15000mm t hp vi 90% hiu ng ca ti trng ln thit k; khong cch gia cc trc 145kN ca mi xe ti phi ly bng 4300mm.

Cc trc bnh xe khng gy ra ng lc ln nht ang xem xt phi b qua.

C ti trng ln v v tr ca b rng 3000mm ca mi ln phi t sao cho gy ra ng lc ln nht. Xe ti thit k hoc xe hai bnh thit k phi b tr trn chiu ngang sao cho tim ca bt k ti trng bnh xe no cng khng gn hn:

Khi thit k bn hng: 300mm tnh t mp va hay lan can


Khi thit k cc b phn khc: 600mm tnh t mp ln xe thit k.

Tr khi c quy nh khc, chiu di ca ln xe thit k hoc mt phn ca n m gy ra ng lc ln

nht phi c cht ti trng ln thit k.

3.6.1.3.2. Cht ti nh gi vng do hot ti tu

Nu Ch u t yu cu tiu chun vng do hot ti tu theo iu 2.5.2.6.2 th vng cn ly

theo tr s ln hn ca:

Kt qu tnh ton do ch mt mnh xe ti thit k, hoc

Kt qu tnh ton ca 25% xe ti thit k cng vi ti trng ln thit k.

3.6.1.3.3. Ti trng thit k dng cho mt cu, h mt cu v bn nh ca cng hp

Nhng quy nh trong iu ny khng c p dng cho mt cu c thit k theo quy nh ca

iu 9.7.2, phng php thit k theo kinh nghim.

Khi bn mt cu v bn np ca cng hp c thit k theo phng php di gn ng theo

iu 4.6.2.1 th cc ng lc phi c xc nh trn c s sau:

Khi cc di c bn l ngang v nhp khng vt qu 4600 mm- cc di ngang phi c thit

k theo cc bnh xe ca trc 145000 N.

Khi cc di c bn l ngang v nhp vt qu 4600mm - cc di ngang phi c thit k theo

cc bnh xe ca trc 145.000 N v ti trng ln.

Khi cc di c bn l dc - cc di ngang phi c thit k theo tt c cc ti trng quy nh

trong iu 3.6.1.2 bao gm c ti trng ln.

Khi dng phng php tnh chnh xc phi xt tt c ti trng quy nh trong iu 3.6.1.2 bao gm c

ti trng ln.

Cc kiu kt cu k c cu bn phi c thit k vi tt c hot ti quy nh trong iu 3.6.1.2 bao

gm ti trng ln.

Ti trng bnh xe phi c gi thit l bng nhau trong phm vi mt n v trc xe v s tng ti

trng bnh xe do cc lc ly tm v lc h_m khng cn a vo tnh ton bn mt cu.

3.6.1.3.4. Ti trng trn bn hng

Khi thit k bn mt cu hng c chiu di hng khng qu 1800mm tnh t trc tim ca dm ngoi cng

n mt ca lan can bng b tng lin tc v kt cu, ti trng bnh xe d_y ngoi cng c th c thay

bng mt ti trng tuyn phn b u vi cng 14,6N/mm t cch b mt lan can 300mm.


Ti trng ngang trn bn hng do lc va ca xe vi ro chn phi ph hp vi quy nh ca Phn 13.

3.6.1.4. Ti trng mi

3.6.1.4.1. ln v dng

Ti trng tnh mi l mt xe ti thit k hoc l cc trc ca n c quy nh trong iu 3.6.1.2.2

nhng vi mt khong cch khng i l 9000 mm gia cc trc 145.000N.

Lc xung kch quy nh trong iu 3.6.2 phi c p dng cho ti trng tnh mi.

3.6.1.4.2. Tn s

Tn s ca ti trng mi phi c ly theo lu lng xe ti trung bnh ngy ca ln xe n (ADTTSL).

Tn s ny phi c p dng cho tt c cc cu kin ca cu, d cho chng nm di ln xe c s xe

ti t hn.

Khi thiu cc thng tin tt hn th ADTT ca ln xe n phi ly nh sau:

ADTTSL = p x ADTT (3.6.1.4.2-1)

trong :

ADTT = s xe ti / ngy theo mt chiu tnh trung bnh trong tui th thit k;

ADTTSL = s xe ti / ngy trong mt ln xe n tnh trung bnh trong tui th thit k; p = ly theo Bng 3.6.1.4.2-1.

Bng 3.6.1.4.2 -1 - Phn s xe ti trong mt ln xe n, p

S ln xe c gi tr cho xe ti p 1 1, 00 2 0, 85 3 0, 80

3.6.1.4.3. Phn b ti trng khi tnh mi

3.6.1.4.3a. Cc phng php chnh xc

Khi cu c tnh ton theo bt k phng php chnh xc no c quy nh trong iu 4.6.3 th mt

xe ti n chic phi c b tr theo chiu ngang v chiu dc sao cho phm vi ng sut trong chi tit

ang xt l ln nht, bt k v tr dng xe hay ln xe thit k trn mt cu.

3.6.1.4.3b. Cc phng php gn ng

Khi cu c tnh ton theo s phn b gn ng ca ti trng nh quy nh trong iu 4.6.2 phi s

dng h s phn b cho mt ln xe.

3.6.1.5. Ti trng b hnh


i vi tt c ng b hnh rng hn 600m phi ly ti trng ngi i b bng 3x10-3 MPa v phi

tnh ng thi cng hot ti xe thit k.

i vi cu ch dnh cho ngi i b v/hoc i xe p phi thit k vi hot ti l 4x10-3 MPa.

Khi ng b hnh, cu cho ngi i b v cu i xe p c dng dng xe bo dng v/hoc xe

ngu nhin th cc ti trng ny phi c xt trong thit k. Lc xung kch ca cc loi xe ny khng

cn phi xt.

3.6.2. Lc xung kch: IM

3.6.2.1. Tng qut

Tr trng hp cho php trong iu 3.6.2.2, tc ng tnh hc ca xe ti hay xe hai trc thit k khng

k lc ly tm v lc h_m, phi c tng thm mt t l phn trm c quy nh trong bng 3.6.2.1.-1

cho lc xung kch.

H s p dng cho ti trng tc dng tnh c ly bng: (1 + IM/100)

Lc xung kch khng c p dng cho ti trng b hnh hoc ti trng ln thit k.

Bng 3.6.2.1-1- Lc xung kch IM

Cu kin IM Mi ni bn mt cu Tt c cc trng thi gii hn

75%

Tt c cc cu kin khc Trng thi gii hn mi v gin Tt c cc trng thi gii hn khc

15% 25%

Tc ng ca lc xung kch i vi cc cu kin vi trong t nh trong Phn 12 phi ly theo

iu 3.6.2.2.

Khng cn xt lc xung kch i vi :

Tng chn khng chu phn lc thng ng t kt cu phn trn

Thnh phn mng nm hon ton di mt t

Lc xung kch c th c chit gim cho cc cu kin tr mi ni, nu _ kim tra cn c theo cc

quy nh ca iu 4.7.2.1

3.6.2.2. Cu kin vi

Lc xung kch tnh bng phn trm i vi cng v cc cu kin vi trong t nu trong Phn 12 phi

ly nh sau:

IM = 33(1,0 - 4,1x10-4 DE) 0% (3.6.2.2-1)

trong :

DE = chiu dy ti thiu ca lp t ph pha trn kt cu (mm)


3.6.3. Lc ly tm : CE

Lc ly tm c ly bng tch s ca cc trng lng trc ca xe ti hay xe hai trc vi h s C ly nh sau;

C = gR

v

3

4 2 (3.6.3-1)

trong : v = tc thit k ng t (m/s);

g = gia tc trng lc 9,807 (m/s2)

R = bn knh cong ca ln xe (m)

Tc thit k ng b khng ly nh hn tr s quy nh trong Tiu chun thit k ng b .

Phi p dng h s ln quy nh trong iu 3.6.1.1.2

Lc ly tm tc dng theo phng nm ngang cch pha trn mt ng 1800mm

3.6.4. Lc hLm: BR

Lc h_m c ly bng 25% ca trng lng cc trc xe ti hay xe hai trc thit k cho mi ln c

t trong tt c cc ln thit k c cht ti theo iu 3.6.1.1.1 v coi nh i cng mt chiu. Cc lc

ny c coi l tc dng theo chiu nm ngang cch pha trn mt ng 1.800mm theo c hai chiu

dc gy ra ng lc ln nht. Tt c cc ln thit k phi c cht ti ng thi i vi cu v coi

nh i cng mt chiu trong tng lai.

Phi p dng h s ln quy nh trong iu 3.6.1.1.2

3.6.5. Lc va ca xe: CT

3.6.5.1. Bo v kt cu

Nhng quy nh trong iu 3.6.5.2 khng cn tun th nu cng trnh c bo v bi:

Nn p;

Kt cu ro chn c lp cao 1370 mm chu c va, chn trong t, t trong phm vi cch b phn cn c bo v 3000 mm; hoc

Ro chn cao 1070 mm t cch b phn cn bo v hn 3000 mm.

nh gi s min tr ny, ro chn phi tng ng v cu to v hnh hc vi mc ngn chn

L3 quy nh trong Phn 13.

3.6.5.2. Xe c v tu ho va vo kt cu

Tr khi c bo v nh quy nh trong iu 3.6.5.1, m tr t trong phm vi cch mp lng ng

b 9000 mm hay trong phm vi 15000 mm n tim ng st u phi thit k cho mt lc tnh tng

ng l 1.800.000N tc dng bt k hng no trong mt phng nm ngang, cch mt t 1200 mm.

Phi p dng

tcn 272-05 full

Education