Kĩ thuật thi công 1

8/21/2019 K thut thi cng 1

1/59

AMH : K thut thi cng & ATL GVHD: PHM TH TRANG

SVTH: V NGHA HU LP 10KX1 19 Trang: 1

PHN TH NHT

NHNG VN LIN QUAN N CNG TRNH

I.GII THIU CNG TRNH:

1. c imcng trnh:* Quy m cng trnh:

-Cng trnh xy dng lchung c vn ng vin, nm trn ng Nguyn

Tt Thnh, TP. Nng

-Ch u t l S Vn ha - Th thao - Du lch thnh ph Nng.

-Cng trnh l khi nh 6 tng v 1 tng mi .

-Chiu cao mi tng l 3.6m v chiu cao tng mi l 4.3m.

-Chiu cao tng th l 27.1m.

-Din tch t xy dng l: 19.5 x 15.2 + 10.6 x 46.72 = 791.632 m2.

* c tnh k thut:

-Phn mng c 14 kiu mng bng, c ton khi bng phng php

th cng.

-Phn thn cng trnh c kch thc dm 200x400 mm.

-Chiu dy sn hs = 100 mm, c 3 loi ct vi cc kch thc 150x200,

150x250 v 200x250.

-Dm sn b tng ct thp ti ch. 2. c im ca khu t xy dng:

-Hng Bc :Gip khi nh 4 tng vi L = 3.8m.

-Hng Ty Bc :Gip khi nh 4 tng vi L = 2.8m

-Hng Nam :Gip ng Nguyn Tt Thnh, cch nh bo vvi

L = 2.77m.

-Hng ng :Gip hng ro vi L = 3.6m.

-Hng Ty :Gip sn th thaovi L = 3.4m.

II.

TNH HNH NI THI CNG:

1. a cht cng trnh:

Cng trnh nm trn nn t p.

2. Giao thng cng trnh:

Cng trnh nm v tr trung tm khu t c khong cch vi 4 pha kh

rng nn thun li cho cng tc tp kt vt liu v thi cng

3. Vt t Cng trnh:

- Cng trnh nm trn mt tin ca ng NguynTt Thnh giao vi2 tuynng Nguyn Lng Bng v ng 3/2nn vic cung cp vt t xy dngcho

cng trnh lun c m bo.


2/59



- H thng cp pha, gin do c cung cp bi mt s cng ty trong thnh

ph Nng.

- Vt liu xy dng c chuyn n cng trng tu theo nhu cu thi cng

v c cha trong cc khobi ti cng trng.

4. a cht thy vn, tnh hnh a hnh:a cht thy vn: Qua kt qu khost a cht, y l khu vc c a

cht tng i n nh, thun tin cho vic xy dng nh cao tng, mc nc

ngm thp hn y mng cng trnhthun tin cho vic thi cng phn mng

cng trnh.

Tnh hnh a hnh: a hnh ton b khu t c xy dngbng phng,

c lm xch c di v san i cc kt cu c .

Kh tng thy vn:

Nng nm trong vng nhit i gi ma in hnh, nhit cao v t

bin ng. Mi nm c 2 ma r rt:

-Ma ma ko di t thng 8 n thng 12.

-Ma kh ko di t thng1 n thng 7, thingr thong c nhng t

rt ma ng nhng khng m v khng ko di.

Gi bo:

-Hng gi chnh l hng ng Nam t thng 4 n thng 9.

-Bo khu vc Nng thng xut hin t thng 9 n thng 11.-S cn bo Nng chim 24,4% tng s cn bo b vo t lin

t v tuyn 17 tr vo

Lng ma trung bnh nm l 2.504,57mm/nm


3/59



PHN TH HAI

THIT K THI CNG H MNG V PHN THN

A. THIT K BIN PHP THI CNG CNG TC T

I.

LU KHI LA CHN BIN PHP THI CNGKhi chn bin php thi cng cn lu :

-S dng c gii ha ti a, nht l cc khu nng nhc, kt hp tt gia c

gii v th cng, gia c gii b phn v c gii tng hp, gim pht sinh

ngng vic, p dng phng thc t chc lao ng tin tin.

-Chn bin php thi cng sao cho s my v loi my phi huy ng l t nht

nhm n gin bt cng tc qun l my v lao ng

- Km theo bin php thi cng phi c bin php an ton lao ng.

-Km bin php thi cng phi c bin php an ton lao ng.

-Ton b hot ng thi cng phi c thc hin sao cho khng c gy tr

ngi, h hng, tn tht cho cc cng trnh k thut h tng cc khu vc xy

dng, mi s c gy ra n v thi cng s t x l khng nh hng n

tin thi cng.

II.

THIT K GII PHP THI CNG H MNG

*Cng tc thi cng h mng bao gm cc bc:

o h mng n cos thit k v vn chuyn t Thi cng vn khun mng

b tng mng

Dng hb tng v p t nn mng cng trnh

Cng trnh c xy dng trn nn t p bng phng nn chng ta khng cn

phi thi cng cng tc san nn m tin hnh thi cng o h mng. chun b

cho cng tc thi cng o h mng, trc ht phi thi cng dn dp mt bng,

cht ph cy ci trong phm vi cng trnh xy dng.

Tin hnh lm h thng tiu nc b mt cho cng trng, o cc rnh xung

quanh h mng vi dc nht nh sao cho nc tp trung v cc h thu ri t

my bm tiu nc

2.1 CNG TC O T H MNG

1. Kim tra gii php m bo an ton cho cng trnh ln cn :

- iu kin a cht: t p.

-Chiu su h mng H = 1.7 + 0.1=1.8 m

-Chiusu h mng o t bng c gii l: Hcg= 1.8-0.2 = 1.6m-Chiu su h mng o t bng th cng l l: H tc= 0.2m.


4/59



-V cng trnh c thi cng trn nn t p l nn t nhn to c x

l nn c h s rng nh, sc chu ti ca nn t cao, tnh nn ln nh,

moun bin dng v cng chng ct cao

-Da vo iu kin a cht cng trnh nu trn v su h mngo, ta

tin hnh tra bng ni suy c gi tr h s mi dc m = 0.68m.Theo bng traH s mi dc(Trang 6Gio trnh KTTC-ATL - Khoa

QLDA).

=> B rng mi dctnh theo chiu su h mng l:

B = m.H = 0.68 x 1.8 = 1.224 (m )

Vi: B rng mi dc khi o c gii l : Bcg= m.Hcg= 0.68x1.6 =

1.088m

B rng mi dc khi o th cng l : Btc= .m.Htc = 0.68x0.2=

0.136m

-Chn b rng thi cng ca cng nhn di h mng lbtc= 0,5 m.

-Gis ta tin hnh o h mng theo mi dc, do cn kim tra khong

cch t nh h mng n cc cng trnh ln cn.

-Pha Bc gip vi khi nh 4 tngvi L1= 3.8m

=> S1= L1 ( B + btc) = 3.8( 1.224 + 0,5 ) = 2.076> 0,5 ( m ) => C th o

h mng theo mi dc.

-Pha Ty Bc gip vi khi nh 4 tngvi L2=2.8m

=> S1= L1 ( B + btc) = 2.8( 1.224 + 0,5 ) = 1.076 > 0,5 ( m ) => C th o

h mng theo mi dc.

-Pha Nam gip vi nh bo v vi L3= 2.77m

=> S1= L1 ( B + btc) = 2.77( 1224 + 0,5 ) = 0.976 > 0,5 ( m ) => C tho h mng theo mi dc.

2. La chn phng n o t h mng :

1.6m

0.2m

1.224m

1.8m


5/59



Da vo tnh cht c l ca t nn ti v tr xy dng cng trnh thi cng

cng tc t, c hai phng n sau :

+- Phng n 1:Phng n thi cng t bng cch o theo mi dc, dc

ca mi t ph thuc vo loi t nn, vo ti trng thi cng trn b mt.

+ Phng n 2:Phng n o t c dng vn c gia c thnh vch t vhn ch nh hng c hi n cc cng trnh ln cn.

+ V cng trnh thi cng l mng bng, nn phng n o t h mng cng

trnh c th o thnh tng rnh mng chy di hay o ton b mt bng cng trnh.

+Nhng vi cng trnh c thi cng trn nn t p c tnh cht c l rt

tt, khi o t khng cn c gia c thnh vch.Mt khc, cng trnh thi cng bng

mng bng giao thoa, ta nn la chn phng n o ton bvi mi dc tnh ton,

d tin hnh thi cng bng my, tit kim c thi gian di chuyn v quay u

my o nhiu ln qua cc rnh h mng, tit kim chi ph nhn cng, chi ph vt liu

lp t ng cng tc cho my o v xe vn chuyn.

a. Kt lun chung:

Ta tin hnh oton b nnt theo 2 giai on:

Giai on 1: Dng my o n su nh hn thit k 200 mm

trnh ph hoi kt cu di y mng, vi su o c gii l

Hcg = 1600 mm.

Giai on 2: o th cng t cn livi Htc = 200 mm v tinhnh sa cha h mng, chun b cho vic thi cng b tng mng.

b. Tnh khi lng o t h mng:

Khi lng t o mng c tnhtheo cng thc:


6/59



V = Vcg+ Vtc

Vi:

Vcg : Th tch khi t o bng c gii.

Vtc :Th tch khi t o bng th cng.

Th tch tng phng n o c tnh theo cng thc sau:

V =6

H[ a.b + (a + c ).( b + d ) + c.d ]

Trong :

a,b : Chiu di chiu rng ca y h o

c,d :Chiu di, chiu rng mt trn h o.

H : Chiu su o mng.

B : B rng mi dc

Khi lng o t c gii:

- thun li cho vic tnh ton khi lng o t bng my, chia h mng thnh

2 khoang o.

- Sau khi tnh ton c th kch thc cc khoang, ta c bng kt qu khi lng o

my nh sau:BNG TNH TON KHI LNG O T BNG C GII

STT Tn khoang oKch thc khoang o

V (m3)

a(mm) b(mm) c(mm) d(mm) B(mm) Hcg(mm)

1 Khoang 1 19652 24552 22100 27000 1088 1600 871.77

2 Khoang 2 25322 9352 27770 11800 1088 1600 457.94

TNG KHI LNG O T BNG C GII Vcg 1329.71

Da vo bng tnh ton, ta c th tch o t c gii l: Vcg= 1329.71 (m3).

Khi lng o t th cng:

i vi vic o th cng, nh thu s cho cng nhn xungkhoang o

o thm mt lp t dy 20 cmva ng n cos thit k -2.3m. Ta tinhnh lp bng tnh ton:

BNG TNH TON KHI LNG O T BNG TH CNG

STTTn khoang

o

Kch thc khoang oV

(m^3)a(mm) b(mm) c(mm) d(mm) B(mm) Htc(mm)

1 Khoang 1 21828 26728 22100 27000 136 200 118.01

2 Khoang 2 27498 11528 27770 11800 136 200 64.47

TNG KHI LNG O T BNG TH CNG Vtc 182.48


7/59



Cn c vo bng tnh ton ta c th tch o t th cng l: Vtc= 182.48 (m3).

Khi lng o t:

Th tch o t h mng l:

Vo= Vcg+ Vtc= 1329.71 + 182.48 = 1512.19 ( m3).

c. Xc nh khi lng t d sau khi thi cng xong phn ngm:

-Tng cng th tch kt cu ngm: VKCngm

-Th tch kt cu ngm chnh bng th tch t i.

Khi lng t li lp mng l:

Vlp mng = Vo- VKC

ngm

*Th tch cc kt cu ngm chim ch: bao gm tng th tch b tng lt h mng v

tng th tch mng bng giao thoa.VKCngm = VDi + Vct ngm - Vgiao thoaVi:

-VDi : l th tch ca mng bng th i () (hnh 2)-Vgiao thoa : l phn th tch ca 2 mng bng ct nhau ti v tr giao thoa (hnh

3)

-Vct ngm : l th tch phn ct trn c mng

(hnh 2)

VDi= V1 + V2 + V3 + V4 = ((500.400)+ .(ai+bi) + (bi.h1) + 100.(200+bi)).Li.10

-9(m3)

(Li : chiu di ca mng bng th i)

V1

500

a

400 5050

100 b 100

100h

1

h2

V2

V3

V4


8/59



(hnh 3)

V phn giao nhau gia 2 mng bng c hnh khi rt phc tp, nn ta quy v mt ct

ca 3 khi hnh ch nht c kch thc trung bnh ln lt l:

- atb=

- btb=

- h3 =

- h = h2+ h3

Vgiaothoa = Vc mnggiao thoa+ V3 + V4

= (400.500.400.10-9) + (

.h+ 100.(200+btb)).btb.10-9(m3)

Ta tin hnh lp bng tnh ton khi lng th tch phn kt cu ngm theo cng thc

nu:

(a + b )/2tb tb

100 b 100

100

h3

h2

V4

V3

tb

h

500

400


9/59



BNG 1: TH TCH MNG BNG

STTTn

mng

KCH THC MNG Slp b tng

lt

(mm2)

Sc mng

(mm2

)

L

(mm)

S

kh

i

V

(m3)

a

(mm)

b

(mm)

h1

(mm)

h2

(mm)

1 D1 400 1800 250 250 20000020000

022100 1 24.86

2 D2 400 1800 250 250 20000020000

022100 2 49.73

3 D3 400 1800 250 250 20000020000

022100 1 24.86

4 D3A 400 1800 250 250 200000 200000

49820 1 56.05

5 D4 400 1800 250 250 20000020000

014650 1 16.48

6D5

(trc 1-4)400 1800 250 250 200000

20000

013100 1 14.74

7D5

(trc 4-6)400 2600 250 250 280000

20000

014650 1 22.05

8 D6 400 1500 250 250 160000 200000

14650 1 14.25

9D7

(trc 1)400 2800 250 250 300000

20000

027000 1 43.20

10D7

(trc 3)400 2300 250 250 250000

20000

027000 1 36.79

11D7

(trc 4)400 2600 250 250 280000

20000

0

27000 1 40.64

12 D8 400 2200 250 250 24000020000

013500 1 17.75

13 D9 400 1800 250 250 20000020000

02400 3 8.10

14 D10 400 1800 250 250 20000020000

011800 5 66.38

15 D10a 400 1600 250 250 17000020000

011800 2 24.07

16 D12 400 2200 250 250 240000 20000 4800 2 12.62


10/59



(trc A-B') 0

17D12

(trc C'-D)400 2200 250 250 240000

20000

04800 2 12.62

18

D12(trc B'-C')

V = (Sc mng+ Slpb tnglt+ b.h1).L

= (400.500+100.3900 + 3900.250).2050.10-9 2 6.41

19 D13 400 260025

0250 280000

200

00011800 1 15.40

20 D14 400 240025

0250 260000

200

00028650 1 34.67

21 D15 400 260025

0250 280000

200

00020650 1 26.95

22 D16 400 1500 250

250 1600 200000

28650 1 17.59

23 D17 400 180025

0250 200000

200

00011850 1 10.96

Tngatb btb Vmng

400 2059.09 597.16

Ghi ch: M ng D11ging kch thc mng D12 nn gp chung thnh 2 khi tnh.

Bng 2: Th tch phn giao thoa gia 2 mng

KCH THC CU KIN GIAO THOASBT lt

(mm2)

Vc mng(mm3)

V1

khi

(m3)

SL

khi

Vgiao thoa(m3)

atb

(mm)

btb

(mm)

h1

(mm)

h2

(mm)

h3

(mm)

400.00 2059.09 250 250 418.67 225909.09 80000000 1.81 69 124.96


11/59



Bng 3: Th tch phn ct ngm

STTTn

mng

KCH THC CU KiN Th tch

1 khi(m3)

S

khi

Vct ngm(m3)

a

(mm)b(mm) h(mm)

1 D1 500 400 700 0.14 3 0.42

600 400 700 0.168 2 0.336

2 D2 500 400 700 0.14 2 0.28

600 400 700 0.168 2 0.336

3 D3 500 400 700 0.14 4 0.56

600 400 700 0.168 3 0.5044 D4 500 400 700 0.14 2 0.28

600 400 700 0.168 2 0.336

5 D5 500 400 700 0.14 4 0.56

400 600 700 0.168 1 0.168

350 600 700 0.147 1 0.147

6 D6 500 400 700 0.14 3 0.42

400 400 700 0.112 2 0.224

350 400 700 0.098 1 0.0987 D7 500 400 700 0.14 4 0.56

400 300 700 0.084 2 0.168

500 300 700 0.105 3 0.315

8 D8 500 400 700 0.14 3 0.42

400 400 700 0.112 1 0.112

9 D10 550 400 700 0.154 5 0.77

600 400 700 0.168 5 0.84

400 400 700 0.112 5 0.5610 D10a 550 400 700 0.154 2 0.308

600 400 700 0.168 2 0.336

400 400 700 0.112 2 0.224

11 D11 500 400 700 0.14 3 0.42

400 400 700 0.112 1 0.112

12 D12 500 350 700 0.1225 2 0.245

500 400 700 0.14 2 0.28

13 D13 500 400 700 0.14 4 0.56TNG TH TCH PHN CT NGM 10.899


12/59



Tng th tch kt cu ngm:

VKCngm = VDi +Vct ngm - Vgiao thoa= 597.16 + 10.899 124.96

= 483.1 (m3)

Vy, th tch t lp mng l:

Vlp mng = Vo- VKC

ngm

= 1512.19483.1

= 1029.09 (m3)

3. La chn my o v s xe vn chuyn phc v cho cng tc o t:

a.Phng n la chn myo:

Vi phng php o t bng c gii, chng ta c th to ra nng sut lm vic cao

hn ng thi gp phn tit kim chi ph v h gi thnh cng trnh.

tin hnh o h mng, ta c th chn mt trong hai phng n sau:

Phng n 1: Dng my o gu thun

- u im:+ My o gu thun c tay cn ngn v xc thun nn o rt kho c th

o c nhng h o su v rng vi t t cp I IV;

+ My o gu thun thch hp dng t ln xe chuyn i. Kt hp

vi xe chuyn t nn b tr quan h gia dung tch gu v dung tch thng xe hp l

s cho nng sut cao, trnh ri vi lng ph;

+ Nu b tr khoang o thch hp th my o gu thun c nng sut cao

nht trong cc loi my o mt gu.

-Nhc im:

+ Khi o t my o phi ng di khoang o thao tc, v vy m

my o gu thun ch lm vic tt nhng h o kh ro khng c nc ngm;

+ Tn cng v chi ph lm ng cho my o v phng tin vn chuyn

ln xung khoang o;

Phng n 2: Dng my o gunghch


13/59



- u im:

+ My o gu nghch cng c tay cn ngn nn o rt kho, c th o

c t t cp I IV.

+ Cng nh my o gu thun, my o gu nghch thch hp o v

t ln xe chuyn i hoc ng. + My c c cu gn nh nn thch hp o cc h o nhng ni cht

hp, cc h o c vch thng ng, thch hp thi cng o h mng cc cng trnh

dn dng v cng nghip.

+ Do ng trn b h o thi cng nn my c th o c cc h o

c nc v khng phi tn cng lm ng ln xung khoang o cho my v phng

tin vn chuyn.

-Nhc im:

+ Khi o t my o ng trn b h o thao tc, v vy cn quan tm

n khong cch t mp my n mp h o m bo n nh cho my.

+ Nng sut thp hn nng sut my o gu thun c cng dung tch gu.

+ Ch thi cng c hiu qu vi nhng h o nng v hp, vi cc h o

rng v su th khng hiu qu.

b.

Chn my o:

Cn c vo u nhc im k trn ca tng loi my v c im ca h mng,

nn nh thu s chn phng n thi cng o t bng my ch o l my ogunghch,khng nhng gii quyt c khi lng t cn thi cng m cn tit

kim c thi gian v cht lng theo yu cu.

Vi khi lng o t bng c gii l Vcg = 1329.71 m3< 20000m3th dung tch

gu c th chn trong khong q = 0,40,65 (m3).

( Bng I.2 Trang 8S tay chn my thi cng Nh xut bn xy dng Ti bn 2008)

3.1 Chn phng n di chuyn ca my ch o:

ng i ca my o c nh hng rt ln trong vic chn chn my thi cng,

do cn c vo mt bng thi cng, ta a ra hai phng n:Phng n 1:My o gu nghch di chuyn theo phng cnh ngn ca h

o.

Phng n 2:My o gu nghch di chuyn theo phng cnh di ca h

o.

Nhn xt:

H o ni thi cng c kch thc hnh ch L ctrng, nn ta chia thnh 2 h

o. H o 1: kch thc phng cnh ngn l 11.8m, phng cnh di l

27.77m.


14/59



H o 2: kch thc phng cnh ngn l 22.1m, phng cnh di l

27m.

Theo phng n 1, do kch thc cnh di ca 2 h o tng ln nn nu

o theo phng n ny s chia lm nhiu khoang o, my o s di chuyn theo

nhiu ng rt phc tp; nu mun chia t khoang o th phi dng my c bn knho rt ln, huy ng my ln nh th dn n cng knh, d gy nh hng cho cc

cng tc chun b trn cng trng, khng ph hp.

Theo phng n 2, th:

Vi h o 1 ta o theo 1 khoang oth ta chn my o vi bn knh

o R1=5.9m

Vi h o 2 th ta chia lm 2 khoang ovi kch thcmi khoang l

11.05x27m th chn my c R2= 5,6m, ng di chuyn n gin, taycn ngn v my gn nh hn. Ph hp vi b tr khu vc t v

khu vc vn chuyn , gia cng vn khun, ct thp.

Kt hp phng n o ca hai h o, ta nn chn my o c Rmax 5.9m

Kt lun:Vi nhng nhn xt trn nn ta chn phng n 2: Ta o h o 1

trc, my o di chuyn phng cnh dica h o 1. Sau khi o ht h o 1,

my chuyn vo khoang o ca h o th 2 v o dc theo phng ca cnh

di.Chn my o gu nghch c Rmax 5,9m.

3.2 Chn my o:Nh vy vi t p, s dng my o gu nghch mt gu, chn my c gu c

q = 0,40,65 m3, theo phng n hng di chuyn my, chn my o gu nghch

c Rmax5,9 m, ta c hai phng n my:

Phng n 1: Chn my o gu nghch EO3322-B1 ca Lin X cvi

cc thng s k thut nh sau:

Dung tch gu: 0,5 m3

Bn knh o ln nht: Rmax = 7.5 m.

Chiu su o ln nht. Ho max = 4,2 m

Chiu cao t ln nht. H max = 4,8 m

Chu k k thut tck= 17 giy.

(Trang 27S tay chn my thi cng Nh xut bn xy dng Ti bn 2008)

-Nng sut l thuyt ca my o:

NLT= .q.Ks.

Trong : Tck: Chu k o t: Tck= tck.Kvt.Kquaytck = 17s : Thi gian ca mt chu k khi gc quay l 90

o.

Kvt: H s ph thuc vo iu kin t ca my.Chn


15/59



Kvt=1,1

khi t ln thng xe.

Kquayl h s ph thuc vo gc quay ca cn vi.Chn

Kquay=1.

=> Tck= tck.Kvt.Kquay = 17.1,1.1 = 18.7 (s ).q: l dung tch gu. ta c q= 0,5m3.

Ks: l H s vi y t o.Chn Ks=1,1.

o: Hsti xp ban u ca t.Chn o= 1,2.=> Nng sut l thuyt:

NLT= .q.Ks.

=

.0,5.1,1.

= 88.24 ( m

3/h )

=> Nng sut thc t ca my o:

NTT = NLT.Z.Ktg

Vi: Z: S gilm vic trong 1 ca.Chn Z =7h.

Ktg: H s s dng thi gian.Ktg=0,7.

=> NTT = NLT.Z.Ktg=88,24.7.0,7 = 432,38 ( m3/ca )

S ca cn o lintc : n = 1329,71/432.38 = 3,08(ca). Chn n = 4ca.

c. Chn t vn chuyn phc v cng tc o t:

B tr xe vn chuyn t d n v tr cch cng trnh ang thi cng 2.5

kmChn t vn chuynxe ti t Kamaz 5501 vicc thng s k thut:

Cng sut ti : 9T.

Trng lng : 6T.

Vn tc di chuyn: 80 km/h.


-Nng sut vn chuyn ca t:

Wt= 7 Trong :

Q l ti trng t Q = 9T.

Ktg: H s s dng thi gian t, chn Ktg = 0,7.

Ktt: H s s dng trng ti ca xe,chn Ktt=1.

Tck: Thi gian mt chu k hot ng ca t vn chuyn.

Tck= tcx+tql+tch.x+td+tg


16/59



Vi: + tcx: Thi gian chy xe tcx=2.Lx.

Lx: qung ng xe chy n bi t cch cng trng thi cng 2,5

km

V: vn tc xe chy, gi nh: V=30km/h.

=> tcx=2.2,5.= 10 (pht). Chn tcx= 10 ( pht).

+ tql: Thi gian quay u v li xe,chn tql=2 pht.

+ td: Thi gian d t xung xe,chn td= 2 pht.

+ tch.x: Thi gian ch xc: tch.x=.Tcko

Vi: l s gu lm y xe =

o: Hsti xp ban u ca t.Chn o= 1,2.: Trng lng ring ca t, chn =1,8 (T/m3).=> =

=

= 12.12 gu, chn = 13 gu.

Ta c Tcko= 20,35(s ) nn suy ra tch.x=13.20,35=264.55 s = 4.41( pht

),chn tch.x=5 (pht )

+ tg: Thi gian i s, tng tc,chn tg= 1 pht.

Vy Tck= tcx+ tql + tch.x+ td + tg= 10 + 2 + 5 + 2 + 1= 20 (pht ).

Kt lun:Nng sut t l:

Wt= 7

= 7

= 73.5 (m3/ca ).

Sau khi tnh ton nng sut ca t ta tin hnh la chn s xe da vo 2 nguyn

tc sau y:

Nguyn tc 1: Tng nng sut cc t phc v cho mt my o phi ln

hn nng sut my o: N my o.

=> N1 o)

=

= 5,88 ( xe), chn N1= 6 xe.


17/59



Nguyn tc 2: S lng t phi m bo my o lm vic lin tc khng

ch xe.

N2.(tql+ t ch.x) tcx+ td+ tg

=> N2 + td + tg

.x = 2 + 1

= 1.85 ( xe), chn N2=2 xe.

Vy chn s xe l N=Max( N1;N2) = 6 xe, suy ra s t vn chuyn phc v cng tc

o t l 6xe.

=> S chuyn xe : n= Q

Wcaoto.

9

8,15,73 =14,7 (chuyn). Chn 15 chuyn.

Thi gian vn chuyn nu dung 1 xe:

Tvc= 483.1/73,5=6,57 ca. Chn 7 ca.

Thi gian vn chuyn nu dng t hp 6 xe:

Tvc= 6/7 = 0.86 ca. Chn 1 ca.

=> Tng thi gian thi cng : Ttc = 4 + 1 = 5 ca.

Phng n 2:Chn my o gu nghch E-652B ca Lin X c, c cc

thng s k thut sau:

Dung tch gu : q = 0,65 m3

.Bn knh o ln nht. Ro max = 9,2 m.

Chiu su o ln nht. Ho max = 5,8 m.

Chiu cao t ln nht. H max = 5,3 m.

Chu k k thut tck= 20 giy.


-Nng sut l thuyt ca myo:

NLT=

.q.Ks.

Trong : Tck: Chu k o t: Tck= tck.Kvt.Kquay

tck = 20s : Thi gian ca mt chu k khi gc quay l 90o.

Kvt: H s ph thuc vo iu kin t ca my.Chn

Kvt=1,1

khi t ln thng xe.

Kquayl h s ph thuc vo gc quay ca cn vi.Chn

Kquay=1.

=> Tck= tck.Kvt.Kquay = 20.1,1.1 = 22 (s ).q: l dung tch gu. ta c q= 0,65 m3.


18/59



Ks: l H s vi y t o.Chn Ks=1,1.

o: Hsti xp ban u ca t.Chn o= 1,2.=> Nng sut l thuyt:

NLT

=

.q.Ks.

=

.0,65.1,1.

=97.5 ( m3/h )

=> Nng sut thc t ca my o:

NTT = NLT.Z.Ktg

Vi : Z: S gi lm vic trong 1 ca.Chn Z =7 h.

Ktg: H s s dng thi gian.Ktg=0,7.

=> NTT = NLT.Z.Ktg=97.5.7.0,7 = 477.75 ( m3/ca )

S ca cn o lin tc : n = 1329,71/477.75 = 2.78(ca). Chn n = 3 ca.

d. Chn t vn chuyn phc v cng tc o t:

B tr xe vn chuyn t d n v tr cch cng trnh ang thi cng 2.5

km

Chn t vn chuyn xe ti t DA110D ca hang Toyota Motors

vicc thng s k thut:

Cng sut ti : 6T.

Trng lng : 5.13T.

Vn tc di chuyn: 80 km/h.(Trang 94S tay chn my thi cng Nh xut bn xy dng Ti bn 2008)

-Nng sut vn chuyn ca t:

Wt= 7

Trong : Q l ti trng t Q = 6T.

Ktg: H s s dng thi gian t, chn Ktg = 0,7.

Ktt: H s s dng trng ti ca xe,chn Ktt=1.

Tck: Thi gian mt chu k hot ng ca t vn chuyn.

Tck= tcx+tql+tch.x+td+tg

Vi: + tcx: Thi gian chy xe tcx=2.Lx.

+ Lx: qung ng xe chy n bi t, gi scch cng trng thi cng 2,5

km


19/59



V: vn tc xe chy, gi nh: V=30 km/h.

=> tcx=2.2,5.= 10 (pht). Chn tcx= 10 ( pht).

+ tql: Thi gian quay u v li xe,chn tql=2 pht.

+ td: Thi gian d t xung xe,chn td= 2 pht.+ tch.x: Thi gian ch xc: tch.x=.Tcko

Vi: l s gu lm y xe =

o: Hsti xp ban u ca t.Chn o= 1,2.

: Trng lng ring ca t, chn =1,8 (T/m3).=> =

=

= 8.08 gu, chn = 9 gu.

Ta c Tcko= 20,35(s ) nn suy ra tch.x=9.20,35=183.15s = 3.05( pht),chn tch.x=4 (pht )

+ tg: Thi gian i s, tng tc,chn tg= 1 pht.

Vy Tck= tcx+ tql + tch.x+ td + tg= 10 + 2 + 4 + 2 + 1= 19 (pht ).

Kt lun: Nng sut t l:

Wt= 7

= 7

= 74.73 (m3/ca ).

Sau khi tnh ton nng sut ca t ta tin hnh la chn s xe da vo 2

nguyn tc sau y:

Nguyn tc 1: Tng nng sut cc t phc v cho mt my o phi

ln hn nng sut my o:

N my o.

=> N1 o)

= = 6.39 ( xe), chn N1= 7 xe. Nguyn tc 2: S lng t phi m bo my o lm vic lin tc

khng ch xe.

N2.(tql+ t ch.x) tcx+ td+ tg

=> N2 + td + tg

.x = 2 + 1

= 2.167 ( xe), chn N2=3 xe.Vy chn s xe l N=Max( N1;N2) = 7 xe, suy ra s t vn chuyn phc v cng tc

o t l 7xe.

=> S chuyn xe : n= Q

Wcaoto.

6

8,173,74 =22.42 (chuyn). Chn 23chuyn.


20/59



Thi gian vn chuyn nu dung 1 xe:

Tvc= 483.1/74.73=6,46 ca. Chn 7 ca.

Thi gian vn chuyn nu dng t hp 7xe:Tvc= 7/7 = 1 ca. Chn 1 ca.

=> Tng thi gian thi cng : Ttc = 3 + 1 = 4 ca.

Ta thy s lng xe huy ng a t i xa 2,5km v tng thi gian thi cng c 2

phng n u tng ng nhau, nu la chn phung n 2 domy c bn knh o

ln hn nn rt cng knh, nh hng n cc cng tc khc trn cng trng, di

chuyn trong khi o cng kh khn hn, v vy xt v mt k thut phng n 1 tt

hn so vi phng n 2. Vy nh thu s chn phng n 1:

- S dng my o gu nghch EO3322-B1, lm vic lin tc 4 ca.

- T hp 6 xe Kamaz55019 tn, lm vic 1 ca.

4. T chc thi cng o t:

Ta tin hnh t chc cng tc o t theo 2 giai on: o t c gii v o

t th cng.

S dng my o gu nghch EO 3322-B1di chuyn theo s my. My o li

dc theo khoang o.Khong cch gia trc ng ca my o n mp ca h oti thiu l:

L = 0,5 x Romax= 0,5 x 7,5 = 3,75 m.

Vy khi di chuyn my phi cch h o t nht 3,75 m m bo an ton.

Ti mi v tr khoang o, my o s o xung n ct nh, xe vn

chuyn t ch sn bn cnh, c miln y gu th my o quay sang ln xe

vn chuyn. Chu k lm vic ca my o v t vn chuyn c tnh ton nh trn

l hp l trnh lng ph thi gian ccxe vn chuyn phi ch nhau.

Khi sa mng bng th cng ch l phi o to rnh thu nc v h thu nc

mi mng nhm phng khi thi cng gp ma cn phi bm nc h mng.

ng thi trc khi thi cng btng lt mng cn nghim thu cos y mng cho

chnh xc.

Vn an ton thi cng t cng cn phi ht sc cht ch. Cng nhn lm vic

phi c trang b y bo h lao ng, ln xung h mng phi lm thang ln

xung, khi tri ma bo phi ngng ngay vic thi cng trnh st l t.Cn ch

n khong cch an ton gia cng nhn v my o m bo an ton cho cngnhn.

Tuyn o th cng phi thit k r rng, m bo thun li khi thi cng, thun li


21/59



khi di chuyn t, gim ti thiu qung ng di chuyn giahai ln o. C th s

b tr cng nhn o t th cng ti cc v tr m my o va o xong.

S di chuyn ca my v t c b tr nh hnh 5.

(hnh 5)

THI CNG O T - MT CT B-B

THI CNG O T - MT CT A-A

200

-2.2001600

1105011050

-2.400AO T CO GIOI

AO T THU?CNG

27770

-0.600


22/59



2.2 CNG TC THI CNG B TNG CT THP CHO MNG2.2.1 Thit b, my xy dng ch yu d kin s dng cho cng tc b tng:

Vi nhng kt cu chnh v khi lng b tng ln, kt hp vi cc iu kin

thi cng v nhn lc v my phc v i km, n v thi cng s ngh n v cung

ng b tng ch b tng n cng trng bng xe chuyn dng ca n v thi cng.Do iu kin mt bng thi cng thun li nn ta d dng dng my bm btng

c ng vi voi di, c th thi cng c bt c mng bngno.

2.2.2 Thit k bin php thi cng b tng ct thp mng:

2.2.3 Yu cu vn khun v lp t vn khun:

Hin nay, vn khun c nhiu loi: vn khun g, vn khun btng, vn khunkim loi, vn khun nha ... Tuy nhin khi s dng bt k loi vn khun no cng

cn phi tun th cc yu cu v gia cng, kt cu v lp dng sau:

- V gia cng v kt cu:

+ m bo n nh, cng v bn.

+ m bo ng hnh dng, kch thc theo bn v thit k.

+ Dng nhanh v tho d dng, khng lm h hng vn khun v khng tc

ng n b tng.

+ Khng gy kh khn khi lp t ct thp v khi m b tng. + m bo kn v bng phng.

+ Dng c nhiu ln. Vn khun kim loi phi dng c t 50 n 80 ln.

Vn khun g phi dng c t 3 - 7 ln.

- V lp dng vn khun:

+ Khi vn chuyn, trc ln, h xung phi lm nh nhng, trnh va chm lm

cho vn khun b bin dng.

+ Khi t vn khun phi cn c vo cc mc trc t trn mt t (cho v tr

v cao). ng thi da vo bn v thi cng m bo kch thc v tr ca cng

Lp ct pha

Lp t ct thp

btng

Dng h btng vtho d vn khun


23/59



trnh. i vi cc b phn quan trng phi thm cc im khng ch d dng trong

vic kim tra i chiu.

+ Mt tip xc gia vn khun v nn i hoc khi b tng trc v khe

h gia cc vn khun phi tht kn khng cho nc xi mng chy ra ngoi.

+ Khi vn khun dng xong cn kim tra v nghim thu theo cc im sau: chnh xc ca vn khun so vi thit k, chnh xc ca cc b phn t sn,

kn k gia cc tm vn khun v gia vn khun vi nn, s vng chc ca vn

khun v gio (ch cc ch ni, ch ta) .

* Quy trnh lp dng vn khun v ct thp

* Lp t vn khun mng:

- Lin kt cc tm vn khun nh hnh li vi nhau.

- Lp ghp cc tm vn khun bao quanh cc mt ca i mng c nh chc

chn bng h chng thnh vn khun.

- Kim tra thng ng ca vn khun.

- Kim tra sa cha v hon chnh ln cui cng trc khi lp ct thp.

* Lp t ct thp:

- Ct thp sau khi gia cng c t vo vn khun.

- m bo ng v tr v dy lp bo v.

- mng nu dng tng thanh mt lp t th tc thi cng s chm nn

ngi ta thng dng dng li thp cho nhanh.2.2.4 Gii thiu, la chn, thit k v kim tra kh nng lm vic ca vn khun

phc v thi cng cng tc btng mng

2.2.4.1Gii thiucc loi vn khun hin c, u nhc im ca tng loi:

Cng tc vn khun tuy khng phi l thnh phn to nn cng trnh nhng n li

ng vai tr quan trng, n to ra hnh dng chun xc theo thit k cho cc cu kin,

l nhn t thc y tin thi cng, gim gi thnh sn phm xy dng. Cng tc vn

khun ph thuc nhiu vo thc t thi cng, l nhn t cn phi cn nhc mang li

li ch kinh t cho ngi thi cng. Hin nay trn th trng ngi ta s dng a dng

vt liu lm vn khun, v a dng hnh thc sn xut -tho lp khi thi cng.

a.Vn khun g:

- G dng ch to vn khun thng l g nhm VII hay VIII.

- u im: sn xut d dng, u t ban u thp hn cc loi vn khun khc

nn thun tin v kh kinh t

- Nhc im:

+

Vn khun g thng hay b ca nh hay lin kt thnh mng ln bngcch ng inh nn nhanh hng, h s lun chuyn b.

+ Thi gian tho lp di hn cc loa vn khun nh hnh khc.


24/59



+ Khi tip xc vi btng vn khun g ht nc gy mt nc b tng v

chng b h mc.

- Phm vi s dng: c s dng rng ri, nht l nhng cng trnh c quy m

nh.

b.

Vn khun kim loi:- c ch to nh hnh, theo nhng modul chun, thng c ch to t

thp CT3, b mt l bn thp mng, c sn v khung cng xung quanh.

- u im:

+ Vn khun thp c cng cao, kh nng chu lc ln.

+ t gy nh hng ph n cht lng b tng.

+ C h s lun chuyn cao, ph hp vi cung cch thit k v thi cng

cng nghip

+ C cu to nh hnh, c cc thng s kch thc c th nn d dng tnh

ton, v thi gian gia cng t hp ngn hn.

- Nhc im: u t ban u ln.

- Phm vi s dng: Vn khun thp nh hnh c s dng ph bin, nht l

dng cho cc cng trnh ln.

c.Vn khun b tng ct thp:

- c ch to bng b tng li thp, trong mt b mt vn khun c

hon thin (mi granite, p ), b tng xong lun trong cng trnh lm lptrang tr b mt.

- tng cng kh nng chu lc v tng nhp, ng thi gim Mc b tng c

th s dng cc loi tm copha b tng ng sut trc hoc dng vt liu nh lm li

ca kt cu nhm lm gim trng lng ca cng trnh v gim gi thnh xy dng

- Phm vi s dng: Loi ny Vit Nam hin nay t s dng, n thng hay s

dng cho cc cng trnh ln v thi cng trong iu kin mt bng rt cht hp, khng

c iu kin gia cng vn khun, ct thp.

d.

Vn khun nha:

- c ch to t nha cao cp, c tnh chu lc v n hi cao.

- u im:

+ y l loi vn khun c nhiu u im nht trong cc loi vn khun,

tm vn khun rt nh, khng b cong vnh, khng b bin dng khi va

p, dnh bm ximng t, d c ra, rt thun li trong qu trnh thi cng.

+ S dng c nhiu ln, lun chuyn cao.

-

Nhc im:+ Vn khun ny phi s dng theo s liu ca nh sn xut ( Vit Nam

ch yu l do nh sn xut Ph Vinh, ch c loi c chiu di 1m, x g


25/59



vn khun phi tun theo ch nh ca nh sn xut), nn khng ch

khng ch ng tnh ton trong s dng.

+ S dng vn khun nha phc tp hn vn khun thp trong vic tnh

ton chu lc ca vn khun khi thi cng b tng.

- Phm vi s dng: Khng thng dng bng vn khun thp, thng s dng cc cng trnh thi cng btng ton khi ln.

e.Vn khun g p khung sn thp:

- Loi ny c b mt vn khun bng g, sn chu lc xung quanh bng thp.

Kt hp c c hai u im ca vn khun g v vn khun thp nh hnh.

- Nhng loi ny th trng t s dng v khi b tng phi qut ln n mt

lp du chng chnh c bit nn lm tng chi ph, bn cnh n ch lp rp theo yu

cu ca kt cu m khng c sn nh hnh nn vic t hp cng rt phc tp v tn

cng.

2.2.4.2 xut, la chn loi vn khun thi cng cng tc b tng:

a. xut loi vn khun:

-Vic tnh ton v chn phng n thi cng cng tc vn khun phc v cho

vic btng da trn c s tnh ton, kim tra kh nng chu lc v so snh kh

nng lun chuyn b vn khun .

-Hin nay do cng ngh thi cng c nhiu tin b nn vic la chn phng n

thi cng cng trnh s dng b vn khun thp nh hnh ang c p dng rt thuntin v hiu qu v s ln s dng b vn khun thp nh hnh l rt ln so vi vn

khun g, b mt ca kt cu cng trnh sau khi tho vn khun rt bngphng m

bo yu cu thm m cng nh cng tc hon thin sau ny, thao tc lp rp vn

khun l n gin cho cng nhn.Tuy nhin nhc im ca loi vn khun thp nh

hnh l trng lng tng i ln.

-Kt hp vi cc u nhc im ca cc loi vn khun c cp bn trn,

chng ti quyt nh la chn loi vn khun thp nh hnh v s dng theo hnh thc

lun lu cho cc kt cu ging nhau.

-Vi nhng kt cu phc tp c ng cong, hoc cc kt cu nh, phc tp,

mang tnh c th ring ta s dng kt hp vi vn khun g thun tin cho vic

ch to.

b. La chn loi vn khun thi cng cng tc b tng:

Hin nay trn th trng Vit Nam c cc i gia sn xut vn khun thp nh

Cng ty Ha Pht, Cng ty Vit c, Cng ty Vit Pht,. Cht lng i lin vi gi

c hoc ch hu mi. Qua kinh nghim nhiu nm thi cng, Cng ty u t muah thng vn khun thuc dng sn phm tng i tt ca Cng ty Ha Pht.

*B vn khun bao gm:


26/59



- Cc tm khun chnh.

- Cc tm gc (trong v ngoi).

- Cc ph kin lin kt: mc kp ch U, cht ch L.

- Thanh chng kim loi.

thun tin cho thi cng cng trnh ta c cc mt s cc loi vn khun phng nh

hnh sau

ModunRng x Di

(mm)Dy (mm) J (cm4) W (cm3)

Trng

lng (kg)

HP-1850

HP-1550

HP-1250

HP-0950

HP-0650

HP-0650

1800x500

1500x500

1200x500

900x500

750x500

600x500

55

55

55

55

55

55

49,45

49,45

49,45

49,45

49,45

49,45

11,94

11,94

11,94

11,94

11,94

11,94

HP-1840

HP-1540

HP-1240

HP-0940HP-0640

HP-0640

1800x400

1500x400

1200x400

900x400750x400

600x400

55

55

55

5555

55

44,3

44,3

44,3

44,344,3

44,3

10,78

10,78

10,78

10,7810,78

10,78

HP-1830

HP-1530

HP-1230

HP-0930

HP-0630

1800x300

1500x300

1200x300

900x300

600x300

55

55

55

55

55

28,46

28,46

28,46

28,46

28,46

6,55

6,55

6,55

6,55

6,55

17,4

16,0

12,8

10,1

6,8

HP-1825HP-1525

HP-1225

HP-0925

HP-0625

1800x2501500x250

1200x250

900x250

600x250

5555

55

55

55

24,2824,28

24,28

24,28

24,28

5,275,27

5,27

5,27

5,27

HP-1820

HP-1520

HP-1220

HP-0920

HP-0620

1800x200

1500x200

1200x200

900x200

600x200

55

55

55

55

55

20,02

20,02

20,02

20,02

20,02

4,42

4,42

4,42

4,42

4,42

14,5

12,4

11,0

8,7

5,5


27/59



HP-1815

HP-1515

1800x150

1500x150

55

55

17,63

17,63

4,3

4,42

HP-1810

HP-1510

HP-0310

1800x100

1500x100

300x100

55

55

55

15,68

15,68

15,68

4,08

4,08

4,08

12,4

10

2,6

Vn khun

thp t ch

500x200x55

400x150x55

300x200x55

300x100x55

200x200x55

200x100x55

Bng c tnh k thut tm khun gc trong:

KiuRng

(mm)

Di

(mm)

Dy

(mm)

700

600

300

1500

1200

900

55

200150

1800

1500

1200

900

600

500

300

250

55


28/59



150150

1200

900

750

600

500

300

250

55

100150

1800

1500

1200

900

600

500

300

250

55

Bng c tnh k thut tm khun gc ngoi:

KiuRng

(mm)

Di

(mm)

100100

1800

1500

1200

900750

600

300

2.2.4.3Thit k vn khun mng:

Mng ca cng trnh thuc loi mng bng giao thoa. Kt cu mng bao bm i

mng v c mng. m bo cho cng tc thi cng b tng, ta i thit k, tnh ton

v kim tra vn khun cho i mng v c mng. Chn mng in hnh thit k vn khun, kch thc Bm x Bm = 6,55m x 2,1m


29/59



a.Thit k v tnh ton vn khun i mng:

Chn vn khun

Chn i mng c kch thc (di x rng) l 6,55m x 2,1m, cao 0,25 m lm

mng in hnh tnh ton thit k vn khun thnh mng.

i vi mt c chiu di 6.55m, chn:

4 tm HP-1225 (1200x250x55)

1 tm HP-1525 (1500x250x55)

i vi mt c chiu di 2,1m, chn:

1 tm HP-1825 (1800x250x55)

Lin kt gia 2 cnh i mng, ta chn 2 tm vn khun gc 250x150x150x55 v 2

tm 250x150x100x55

Cc c trng qun tnh ca cc tm trn xem bng. Nhng tm vn khun HP-1825, HP-1525, HP-1225 c lp theo phng

ngang, nhng tm vn khun gc trong c lp 4 gc ca mng.

Tnh ton kh nng lm vic ca vn khun(xc nh khong cch gia

cc thanh chng)

i vi cnh di 6,55m:

Bc u ta gi thit cho cc tm vn khun lm vic nh dm lin tc, vi cc gi

ta l cc thanhchng ng

S dng tm vn khun c tit din ln nht tnh ton.Chn tm vn khun HP-1525 (1500x250xx55) c mmen qun tnh J=24,28 cm4,

mmen chng xon W=5,27 cm3

LL

L

q

M= ql /102

* Xc nh p lc tc dng ln b mt vn khun:

p lc ngang ca btng :

Pb= bt.H = 2500 x 0.25 = 625 (kG/m2)

bt : dung trng ca b tng ct thp, = 2500 kg/m3.

H : Chiu cao btng i mng (m).

p lc do m gy ra:

PTC= bt. H nu H RmP

TC= bt. R mnu H > Rm


30/59



S dng m chn ng 116 c thng s k thut:

NS = (3 - 6) m3/gi

Bn knh nh hng: Rah = 35 cm

Chiu su m: H = 30 cm.

V H < Rm nn:

Ptc

= bt.H = 2500.0,25 = 625 (kG/m2)

p lc tc dng ln vn khun mng hay ti trng tiu chun tc dng ln vn

khun thnh mng:

qtc = Ptc+ Pb

qtc = 625 + 625 = 1250 (kG/m2)

y ch l ti trng tiu chun tc dng ln vn khun thnh mng, cn

trong thc t th ti trng tnh ton lun km theo h s vt ti n.Chn h s vt ti n=1,3

(Bng 8.2 Trang 97Gio trnh KTTC v ATL)

Ta c, ti trng tnh ton tc dng ln vn khun thnh mng:

qtt = 1,3.Ptc+ 1,3.Pb

qtt= 1,3.625 + 1,3.625 = 1625m (kG/m2)

Ti trng tc dng vo 1 tm vn khun c b rng 0,25m:

Ti trng tiu chun: qtc= 1250x0,25 = 312,5 (kG/m)Ti trng tnh ton: qtt= 1625x0,25 = 406,25 (kG/m)

* Tnh ton kim tra kh nng lm vic ca vn khun:

Cng thc tnh moment ln nht trong kim tra iu kin cng :

Mmax=8

2lqTT : i vi dm n gin

Mmax=10

2lqTT : i vi dm lin tc

Cng thc kim tra iu kin v bin dng:

400

1

.364

5 3

l

f

JE

lqtc

l

f: i vi dm n gin

400

1

.

'

128

1 3

l

f

JE

lqtc

l

f: i vi dm lin tc.

+ Kim tra theo iu kin cng :

].[.10

. 2

max nW

lq

W

M tt = RkCT3= 2100 kg/cm2


31/59



l ttq

W.10].[ => l 210010.5,27

40625.102 =165,05 (cm ).

+ Kim tra iu kin v vng:

4001][

E.Jlq.

1281

lf

3tc

lfcc

=> 400

3=1282,1.1062428

40031251023

= 173,48 (cm)

Nh vy ta phi dng 2ct chng vi khong cch l 150cm s tha iu kin v

cng v vng.

V theophng cnh di c ghp bi 4loi vn khun. Theo tnh ton, ta thy tm

vn khun c l = 1500 tha mn cc iu kin v cng v vng, nn tm vn

khun cn li c l = 1200mm v tm vn khun gc c l = 150mm, l = 100mm cng

tha mn iu kin v cng v vng. Nh vy, theo phng cnh di c

khong cch 2ct chng l l = 150cm v l = 120cm.

i vi cnh ngn 2,1m

Theo phng chiu di c ghp bi 3 tm vn khun(1 tm phng v 2 tm vn

khun gc), s dng tm vn khun c tit din ln nht tnh ton.

Chn tm vn khun HP-1830 (1800x250x55) c mmen qun tnh J=24,28 cm4,

mmen chng xon W=5,27 cm

3

Ta gi thit cho cc tm vn khun lm vic nh dm lin tc, vi cc gi ta l cc

thanh chng ng

LL

L

q

M= ql /102

* Xc nh p lc tc dng ln b mt vn khun:p lc ngang ca btng :

Pb= bt.H = 2500 x 0.25 = 625 (kG/m2)


H : Chiu cao btng i mng (m).

p lc do m gy ra:

PTC

= bt. H nu H RmP

TC= bt. R mnu H > Rm


32/59




NS = (3 - 6) m3/gi



V H < Rm nn:

Ptc

= bt.H = 2500.0,25 = 625 (kG/m2)


khun thnh mng:

qtc = Ptc+ Pb

qtc = 625 + 625 = 1250 (kG/m2)


trong thc t th ti trng tnh ton lun km theo h s vt ti n.Chn h s vt ti n=1,3



qtt = 1,3.Ptc+ 1,3.Pb

qtt= 1,3.625 + 1,3.625 = 1625m (kG/m2)


Ti trng tiu chun: qtc= 1250x0,3 = 375 (kG/m)

Ti trng tnh ton: qtt= 1625x0,3 = 487,5 (kG/m)* Tnh ton kim tra kh nng lm vic ca vn khun:


Mmax=8


Mmax=10



400

1

.364

5 3

l

f

JE

lqtc

l

f: i vi dm n gin

400

1

.

'

128

1 3

l

f

JE

lqtc

l

f: i vi dm lin tc.


].[.10

. 2max nW

lq

W


l ttq

W.10].[ => l 210010.5,2740625.102 =165,05 (cm ).


33/59




400

1][

E.J

lq.

128

1

l

f 3tc

l

fcc

=> 4003

=128

2,1.106

24

28

40031251023

= 173,48 (cm)

Nh vy ta phi dng 3 ct chng vi khong cch l 90 cm s tha iu kin v

cng v vng.

V theo phng cnh di c ghp bi 3 loi vn khun. Theo tnh ton, ta thy tm

vn khun c l = 1800 tha mn cc iu kin v cng v vng, nn cc tm

vn khun gc cn li c l = 1500 mm v l = 100mm cng tha mn iu kin v

cng v vng. Nh vy, theo phng cnh di c khong cch 3 ct chng l l

= 90cm, l = 15cm v l = 10cm.b. Thit k v tnh ton vn khun c mng

- Kch thc ca c mng : 8,8m x 3,4m x 0,5m.


4 tm HP-1850 (1800x500x55)

1 tm HP-0950 (900x500x55)

2 tm vn khun thp t ch(500x200x55)


1 tm HP-1850 (1800x500x55)

1 tm HP-1250 (1200x500x55)

1 tm vn khun t ch (500x200x55)

Ngoi ra, 4 gc ca c mng, ta dung thm 4 tm vn khun gc (2 tm

100x150x500x55, 2 tm 150x150x500x55) v chn cnh di 150mm theo phng

cnh di 8,8m, chn cnh di 100mm theo phng cnh ngn di 3,4m.

Tnh ton kh nng lm vic ca vn khun(xc nh khong cch gia

cc thanh chng) i vi cnh di 8,8m:

Theo phng chiu di c ghp bi 9 tm vn khun(5 tm phng v 2 tm vn





thanh chng ng


34/59



LL

L

q

M= ql /10

2



Pb= bt.H = 2500 x 0,5 = 1250 (kG/m2)


H : Chiu cao btng cmng (m).

p lc do m gy ra:P

TC= bt. H nu H Rm

PTC= bt. R mnu H > Rm


NS = (3 - 6) m3/gi



V H > Rm nn:P

tc = bt.Rm= 2500.0,35 = 875 (kG/m

2)

p lc tc dng lnvn khun mng hay ti trng tiu chun tc dng ln vn

khun thnh mng:

qtc = Ptc+ Pb

qtc = 875 + 1250 = 2125 (kG/m2)


trong thc t th ti trng tnh ton lun km theo h s vt ti n.

Chn h s vt ti n=1,3(Bng 8.2 Trang 97Gio trnh KTTC v ATL)


qtt = 1,3.Ptc+ 1,3.Pb

qtt= 1,3.875 + 1,3.1250 = 2762,5 (kG/m2)


Ti trng tiu chun: qtc= 2125x0,5 = 1062,5 (kG/m)

Ti trng tnh ton: qtt= 2762,5x0,5 = 1381,25 (kG/m)


Cng thc tnh moment ln nht trong kimtra iu kin cng :


35/59



Mmax=8


Mmax=10



400

1

.364

5 3

l

f

JE

lqtc

l

f: i vi dm n gin

400

1

.

'

128

1 3

l

f

JE

lqtc

l

f: i vi dm lin tc.


].[.10

. 2

max nW

lq

W


l ttq

W.10].[ => l 210010.11,94

138125.102 =134,73 (cm ).


400

1][

E.J

lq.

128

1

l

f 3tc

l

fcc

=> 400

3=1282,1.1064945

400

1062

5

102

3= 146,24 (cm)


cng v vng.




cng v vng. Nh vy, theo phng cnh di c khong cch 2 ct chng l l

= 90cm, v l = 20cm.

i vi cnh ngn 3,4mTheo phng chiu di c ghp bi 5 tm vn khun(3 tm phng v 2 tm vn





thanh chng ng


36/59



LL

L

q

M= ql /10

2



Pb= bt.H = 2500 x 0,5 = 1250 (kG/m2)


H : Chiu cao b tng c mng (m).

p lc do m gy ra:P

TC= bt. H nu H Rm

PTC= bt. R mnu H > Rm


NS = (3 - 6) m3/gi



V H > Rm nn:P

tc = bt.Rm= 2500.0,35 = 875 (kG/m

2)

p lc tc dng lnvn khun mng hay ti trng tiu chun tc dng ln vn

khun thnh mng:

qtc = Ptc+ Pb

qtc = 875 + 1250 = 2125 (kG/m2)


trong thc t th ti trng tnh ton lun km theo h s vt ti n.

Chn h s vt ti n=1,3(Bng 8.2 Trang 97Gio trnh KTTC v ATL)


qtt = 1,3.Ptc+ 1,3.Pb

qtt= 1,3.875 + 1,3.1250 = 2762,5 (kG/m2)





Cng thc tnh moment ln nht trong kimtra iu kin cng :


37/59



Mmax=8


Mmax=10



400

1

.364

5 3

l

f

JE

lqtc

l

f: i vi dm n gin

400

1

.

'

128

1 3

l

f

JE

lqtc

l

f: i vi dm lin tc.


].[.10

. 2

max nW

lq

W


l ttq

W.10].[ => l 210010.11,94

138125.102 =134,73 (cm ).


400

1][

E.J

lq.

128

1

l

f 3tc

l

fcc

=> 400

3=1282,1.1064945

400

1062

5

102

3= 146,24 (cm)


cng v vng.




cng v vng nh tnh ton. Nh vy, theo phng cnh di c 3 khong

cch ct chng l l = 90cm, l = 120cm v l = 20cm.

c. Thit k v tnh ton vn khun ctc mngVy kch thc ctcn thit k vn khun l 900x 400 x 500.

+ Cn c vo kch thc trn, ta chn vn khun nh sau:

- i vi cnh 0,5m : chn 1tm HP-0650(600x500), 1 tm HP-0320(300x200)


Ti cc gc, ta dng 2 tm vn khun gc trong 100x150x300x55

+ Bc u ta gi thit cho cc tm vn khun ct lm vic nhdm lin tc, cc

gi ta l cc gng ct, hoc khung nh v v gng ct (i vi tm bt u t sn,

nn):


38/59



i vi cnh di 0,5m

Xt kh nng lm vic ca tm vn khun HP-0650 (600x500)

L

L

L

q

M= ql /10

2

+ p lc ngang tc dng ln vn khun ct gm 2 thnh phn:

- p lc ngang ca va btng mi :

Pb= . H= 2500 x 0,9 = 2250 (kg/ m2).

- dung trng ca b tng ct thp, = 2500 kg/m3

.HChiu cao btng ct (m).

- p lc tc dng vo thnh vn khun do m chn ng:

PTC= . H nu H < Rm

PTC= . Rmnu H >Rm


NS = (3 - 6) m3/gi

Bn knh nh hng: Rah = 35 cmChiu su m: H = 30 cm.

V H > Rm nn:

Ptc

= bt.Rm= 2500.0,35 = 875 (kG/m2)


khun ct:

qtc = (Ptc+ Pb)

qtc = (875 + 2250) = 3125 (kG/m2)

y ch l ti trng tiu chun tc dng ln vn khun ct, cn trong thc t thti trng tnh ton lun km theo h s vt ti n.

Chn h s vt ti n=1,3


Ta c, ti trng tnh ton tc dng ln vn khun ct:

qtt = (1,3.Ptc+ 1,3.Pb)

qtt= 1,3.875 + 1,3.2250 = 4062,5(kG/m2)




39/59



Ti trng tnh ton: qtt= 4062,5x0,5 = 2031,25(kG/m)



Mmax=8


Mmax=10



400

1

.364

5 3

l

f

JE

lqtc

l

f: i vi dm n gin

400

1

.

'

128

1 3

l

f

JE

lqtc

l

f

: i vi dm lin tc.


].[.10

. 2

max nW

lq

W


lgc ttq

W.10].[ => lgc10.11,94.=111,1 (cm ).


400

1][

E.J

lq.

128

1

l

f 3tc

l

fcc

=> 4003 =1282,1.1064945

40051023

= 128,6 (cm)

Nh vylgc=min( 111,1 ; 128,6cm ) th s tha iu kin v cng v vng.

i vi cnh di 0,4m


LL

L

q

M= ql /10

2



Pb= . H= 2500 x 0,9 = 2250 (kg/ m2).

- dung trng ca b tng ct thp, = 2500 kg/m3.


40/59



HChiu cao btng ct (m).


PTC= . H nu H < Rm

PTC= . Rmnu H >Rm


NS = (3 - 6) m3/gi



V H > Rm nn:

Ptc

= bt.Rm= 2500.0,35 = 875 (kG/m2)


khun ct:qtc = (P

tc+ Pb)

qtc = (875 + 2250) = 3125 (kG/m2)

y ch l ti trng tiu chun tc dng ln vn khun ct, cn trong thc t th

ti trng tnh ton lun km theo h s vt ti n.

Chn h s vt ti n=1,3



qtt = (1,3.Ptc+ 1,3.Pb)

qtt= 1,3.875 + 1,3.2250 = 4062,5(kG/m2)



Ti trng tnh ton: qtt= 4062,5x0,4 = 1625(kG/m)


Cng thc tnh moment ln nht trong kim tra iu kin cng :Mmax=

8


Mmax=10



400

1

.364

5 3

l

f

JE

lqtc

l

f: i vi dm n gin


41/59



400

1

.

'

128

1 3

l

f

JE

lqtc

l

f: i vi dm lin tc.


].[.10

. 2

max

nW

lq

W

M tt = R

k

CT3= 2100 kg/cm

2

lgc ttq

W.10].[ => lgc210010.10,78.102 =118,03 (cm ).


400

1][

E.J

lq.

128

1

l

f 3tc

l

fcc

=> 4003 = 2,1.

= 130,46 (cm)


Kt lun: Theo phng 2 cnh, lgc= min( 111,1; 128,6; 118,03; 130,46) th s tha

mn iu kin v cng v vng.V vy ta chn l gc= 60 cm i vi vn khun

HP-6050, HP-6040v lgc= 30 cm i vi vn khun thp t ch 300x200=> s gng

c phi dng i vi vn khunct l 3gng c.

Bng thng k vn khun mng in hnh.

STT CU KIN LOI VN KHUNKCH THC

(mm)

S

LNG1 BNMNG(Tm,chic)

SLNG1 MNG

INHNH(Tm,chic)

1 Vn khun thng

HP-1850 1800x500x55 5 10HP-1250 1200x500x55 1 2

HP-0950 900x500x55 1 2

HP-1825 1800x250x55 1 2HP-1525 1500x250x55 1 2

HP-1225 1200x250x55 4 8Vn khun thp

t ch500x200x55 2 4

HP-0650 600x500x55 1 2HP-0640 600x400x55 1 2

Vn khun thpt ch

300x200x55 4 8

2 Vn khun gc

500x100x150x55 4 8

25x150x150x55 2 4

300x100x150x55 2 4250x150x100x55 2 4


42/59



2.3 CNG TC THI CNG B TNG CT THP PHN THN

* Thi cng phn thn bao gm cc bc :

- Thi cng cppha

- Thi cng ct thp.

-

Thi cng b tng.- Thi cng xy tng

2.3.1 Quy trnh thi cng ct

2.3.2 Quy trnh thi cng dm, sn, cu thang

2.3.3 Thit k vn khun phn thn.

Lp t ct thp

Lp t cp-pha

btng + Dng h

Tho d vn khun

Kim tra v nghim thu

Lp t cp-pha

Lp t ct thp

btng + Dng h

Tho d vn khun

Kim tra v nghim thu


43/59



*Ni dung tnh ton bao gm :

- Thng k cc loi kt cu cn thit k vn khun.

- Chn s b cc tm vn khun cho kt cu .

- Kim tra kh nng chu lc v vng ca vn khun thp nh hnh (nhptnh ton theo nh hnh tng tm).

- Chn v tnh ton khong cch gng ct.

- Chn tit din x g thp, tnh v kim tra vng ca x g.

- Kim tra khong cch gia cc ct chng, kh nng chu lc n nh ca

ct chng.

Tnh vn khun thc cht l tnh kh nng chu lc ca vn khun nh hnh.

Do s dng cc loi tm vn khun nh hnh c k trc tip ln cc gi l x

g thp nh hnh nn ta xem s lm vic l dm n gin. Nu vic tnh ton

khng tho mn th ta tnh theo dm lin tc.

- d dng cho vic s dng ta tin hnh tnh ton cho tm vn khun nh

hnh c kh nng chu lc b, iu s tho mn cho cc tm chu lc ln.

- H vn khun nh hnh lin kt li v gc ln x g thp, x g thp c

bi cc ct chng thp hoc gc ln thanh lin kt vi vn khun dm.

a. Thit k v tnh ton vn khun ct

Chiu cao ct thit k vn khun:H = Chiu cao tngchiucao dm khong h thi cng mch ngng

= 360040050

= 3150

Vy kch thc ct cn thit k vn khun l 3150 x 400 x 500.

+ Cn c vo kch thc trn, ta chn vn khun nh sau:


- i vi cnh 0,4m : chn 2 tm HP-1240(1200x400), 1 tm HP-0640(750x400)

- Ti gc ngoi dng 4 thanh trt gc lin kt cc tm khc mt. Cc tm vnkhun ny t thng ng.

+ Bc u ta gi thit cho cc tm vn khun ct lm vic nhdm lin tc, cc

gi ta l cc gng ct, hoc khung nh v v gng ct (i vi tm bt u t sn,

nn):

i vi cnh di 0,5m



44/59



LL

L

q

M= ql /10

2



Pb= . H= 2500 x 1,2 = 3000 (kg/ m2).




PTC= . H nu H < RmP

TC= . Rmnu H >Rm


NS = (3 - 6) m3/gi



V H > Rm nn:

Ptc

= bt.Rm= 2500.0,35 = 875 (kG/m2

)p lc tc dng ln vn khun mng hay ti trng tiu chun tc dng ln vn

khun ct:

qtc = (Ptc+ Pb)

qtc = (875 + 3000) = 3875 (kG/m2)


ti trng tnh ton lun kmtheo h s vt ti n.

Chn h s vt ti n=1,3



qtt = (1,3.Ptc+ 1,3.Pb)

qtt= 1,3.875 + 1,3.3000 = 5037,5 (kG/m2)







45/59



Mmax=8


Mmax=10



400

1

.364

5 3

l

f

JE

lqtc

l

f: i vi dm n gin

400

1

.

'

128

1 3

l

f

JE

lqtc

l

f: i vi dm lin tc.


].[.10

. 2

max nW

lq

W


lgc ttq

W.10].[ => lgc10.11,94.=99,77 (cm ).


400

1][

E.J

lq.

128

1

l

f 3tc

l

fcc

=> 400

3=1282,1.1064945

400

5

102

3= 119,7 (cm)


i vi cnh di 0,4m


L

L

L

q

M= ql /10

2

+ p lc ngang tcdng ln vn khun ct gm 2 thnh phn:


Pb= . H= 2500 x 1,2 = 3000 (kg/ m2).




PTC

= . H nu H < RmP

TC= . Rmnu H >Rm


46/59




NS = (3 - 6) m3/gi



V H > Rm nn:

Ptc

= bt.Rm= 2500.0,35 = 875 (kG/m2)


khun ct:

qtc = (Ptc+ Pb)

qtc = (875 + 3000) = 3875 (kG/m2)


ti trng tnh ton lun kmtheo h s vt ti n.Chn h s vt ti n=1,3



qtt = (1,3.Ptc+ 1,3.Pb)

qtt= 1,3.875 + 1,3.3000 = 5037,5 (kG/m2)



Ti trng tnh ton: qtt= 5037,5x0,4 = 2015 (kG/m)* Tnh ton kim tra kh nng lm vic ca vn khun:


Mmax=8


Mmax=10



400

1

.364

5 3

l

f

JE

lqtc

l

f: i vi dm n gin

400

1

.

'

128

1 3

l

f

JE

lqtc

l

f: i vi dm lin tc.


].[.10

. 2max nW

lq

W


lgc ttq

W.10].[ => lgc210010.10,785.102 =105,99 (cm ).


47/59




400

1][

E.J

lq.

128

1

l

f 3tc

l

fcc

=> 4003

= 2,1.

= 121,43 (cm)

Nh vylgc=min(105,99 ; 121,43cm ) th s tha iu kin v cng v

vng.

Kt lun: Theo phng 2 cnh, lgc= min( 99,77; 119,7; 105,99 ; 121,43) th s tha

mn iu kin v cng v vng.V vy ta chn l gc= 60 cm i vi vn khun

HP-1250, HP-1240v lgc= 75cm i vi vn khun HP-0650, HP-0640 => s gng

c phi dng i vi vn khunct l 6gng c.

b. Thit k v tnh ton vn khun dm, sn*Vn khun sn

H vn khun sn bao gm vn khun sn, h x g vn khun sn, h ct

chng x g. Ngoi ra cn c h ging cho gi cho h bt bin hnh.

Cc tng c b dy sn v kch thc cc sn khng ging nhau nn ta la chn

sn c din tch ln nht tnh ton. Nu h vn khun, ct chng, x g chn

cho sn ny tha mn kh nng chu lc v iu kin lm vic th xem nh l

tha mn cho tt c cc sn.

Chn sn thit k vn khun c kch thc 9000x3900x100 (mm)(k cphn gc ln dm)

Ni dung tnh ton gm cc bc:

- Kim tra kh nng chu lc v vng ca vn khun thp nh hnh (nhp

tnh ton theo nhp tng tm).

- Chn loi x g l x g thp, tnh khong cch x g v kim tra vng

ca x g.

- Kim tra v chn khong cch gia cc ct chng, chn ct chng vn

y dm.

+ X g thp vn khun sn.

+ Ct chng n bng thp x g.

*Chn vn khun sn

- Kch thc sn cn thit k vn khun :

Cnh di : 9000 200 = 8800 mm

Cnh ngn : 3900 200 = 3700 mm.

* Vi cnh di 8,8m: Ta b tr 3 tm HP-1830, 2 tm HP-1530 v 2 tm vnkhun gc 200x150x55.


48/59



* Vi cnh ngn 3,7m: Ta b tr 11 tm HP-1830 v 2 tm vn khun gc

200x150x55.

- Vi kch thc sn nh trn ta tin hnh chn vn khun nh sau:

33 tm HP-1830

22 tm HP-15306 tm vn khun gc trong1800x200x150x55

8 tm vn khun gc trong 1500x200x150x55

2 tm vn khun gc trong 400x200x150x55

* Tnh ton khong cch gia cch thanh x g

Trong 1 sn nu c nhiu loi vn khun chu cng ti trng, c cng kch

thc b rng v s tnh nh nhau th tm vn khun no c chiu di tnh

ton ln hn th ch cn tnh ton v kim tra cho tm vn khun m thi.

Ta i tnh ton v kim tra iu kin lm vic ca tm vn khun HP-1830 c

J = 28,46 cm4, W = 6,55 cm3v g = 17,4 kg

i vi vn khun sn th ti trng tc dng ln n l ti trng thng ng: bao

gm tnh ti v hot ti:

Tnh ti:

- Ti trng bn thn ca kt cu sn: l trng lng tng cng ca b tng

v ct thp.

Ps=.hsVi: = + = 2500 + 100 = 2600(kg/m3)

hs = 0.1 (m)

Suy ra: p1= 2600 x 0,1 = 260 (kg/m2).

- Ti trng bn thn ca vn khun: Vn khun bng thp.

Pvk =

=32,2( kg/m2).Hot ti:

- Hot ti do ngi v thit b thi cnggy ra : p = 250 (kg/m2)

- Hot ti do chn ng trong cng tc b tng th cng :pbt= 250 (kg/m2)

Vy, t hp ti trng tc dng ln tm vn khun c chiu rng b = 300mm:

Ti trng tiu chun: qtc = (ps + pvk+p + pbt).b

= (260 + 32,2 + 250 +250).0,3

= 237,66 (kg/m).

Ti trng tnh ton: qtt = (1,2.ps + 1,1. Pvk+ 1,3.p+ 1,3.pbt).b

= (1,2.260 + 1,1.32,2 + 1,3.250 +1,3.250).0,3

= 299,23 (kg/m)


49/59



* Tnh ton kim tra kh nng lm vic ca vn khun

Xem tm vn khun nh dm lin tc, cc gi ta l cc x g.

ll l

q

M= ql /102


].[.10

. 2

max nW

lq

W


lx gttq

W.10].[ => lx g

210010.6,55.102

= 214,4 (cm ).


400

1][

E.J

lq.

128

1

l

f 3tc

l

fcc

=> 4003 = 2,1.

= 200,39 (cm)

Suy ra lx g = 180cm tha mn yu cu v cng v vng

Nh vy ta c lx g =1800 mm, v vn khun HP-1530 c chiu di nh hn HP-1830nn ta chn lx g k vn khun HP-1530 l lx g = 1500 mm tha mn yu cu v

cng v vng.

* Tnh ton x g v ct chng:

- X g t trc tip di h vn khun. Cc thanh x g ngang c cc gi ta

l ct chng.

- S tnh thanh x g ngang ta xem nh 1 dm lin tc c nhp l khong

cch gia cc ct chng. Cc ct chng lin kt vi nhau bng thanh ging.

- Chn titdin x g ngang ri sau kim tra, tnh ton khong cch cc ctchng. Ta tnh ton vi sn ln nht 8800x3700, vn khun sn song song vi cnh

di, x g sn song song vi cnh ngn. Nh vy, tnh ton x g v ct chng x

g theo phng cnh ngn 3700 mm.


50/59



S tnh:

ll l

q

M= ql /102

Chn trc tit din x g sau kim tra iu kin cng v vng.

X g l dm lin tc c cc gi ta l cc ct chng.

Chn x g thp ch I c cc c trng sau y :

W = 10 cm3, J = 35,3 cm4Trng lng bn thn : g = 11,1 kG/m

X g chu ti trng phn b u. Ti trng t tm vn sn tc dng ln x g.

Ti trng tiu chun : qtc= 237,66 + 11,1 = 248,76 (kG/m)

Ti trng tnh ton : qtt= 299,23 + 1,1.11,1 = 310,33 (kG/m)

Tnh ton khong cch gia cc ct chng : x g gc ln ct chng nh 1 dm

lin tc c cc gi ta l ct chng.

iu kin bn :

uRnW

M ].[max

10

.lqM

2

c

tt

max tt

uxg

q

.W10.Rl

Trong : Ru : Cng chu un ca vn khun. Ru= 2100 kG/cm2

cm13,26033,310

10.10.2100.10

q

.W10.Rl

2

tt

uc

Theo iu kin bin dng :

400

1

.128

1 3

l

f

JE

lq

l

f cTC

cmq

JEl

tc

c 06,21210.76,248.400

3,35.10.1,2.128

.400

..1283

2

6

3

thun tin cho thi cng, yu cu x g 2 u phi t cch dm 250mm -

300mmTa chn khong cch ny l 250mm.

Vy, chn khong cch gia cc ct chng x g sn l 1600mm tha mn


51/59



ng thi v iu kin cng v vng.

* B tr, tnh ton v kim tra iu kin lm vic ca ct chng

D kin s dng ct chng thp c chiu di thay i c ca Cng ty Ha

Pht sn xut.

Loi

Chiu

cao ng

ngoi

(mm)

Chiu

cao ng

trong

(mm)

Chiu cao s dng Ti trngTrng

lng

(kg)

Ti thiu

(mm)

Ti a

(mm)

Khi

ko

(kg)

Khi nn

(kg)

K-102 1500 2000 2000 3500 2000 1500 10,2

K-103 1500 2400 2400 3900 1900 1300 11,1

K-103B 1500 2500 2500 4000 1850 1250 11,8K-104 1500 2700 2700 4200 1800 1200 12,3

K-105 1500 3000 3000 4500 1700 1100 13

K-106 1500 3500 3500 5000 1600 1000 14

- ng ngoi (phn ct di) : D1= 60mm ; = 5mm ; d1= 50mm.

- ng trong (phn ct trn) : D2= 42mm ; = 5mm ; d2= 32mm.

Ta s dng ct chng K-103B c chiu di s dng ti a 4,0m, ti trng chophp khi s dng : 1250kG, trng lng 11,1 kG

Kim tra ct chng:

- S tnh ton ct chng l thanh chu nn 2 u lin kt khp, b tr h

ging ct chng theo 2 phng (phng vung gc v phng ca x g). Xem v tr

t thanh ging ti ch ni gia 2 on ct.

- P = qtt.lc= 310,33x1,5= 465,5 kG < 1250kG: m bo kh nng chu lc

Chiu cao yu cu ca ct chng l: H = 3,6-0,1-0,1-0,055 = 3,345 m, nh vy

ct chng K-103B tho mn cc yu cu v ti trng v chiu cao tng.* Vn khun dm:

Tit din dm 200x400. Ta tnh ton vn khun i vi 2 dm cnh 9000 v

cnh 3900

+ i vi dm cnh 9000:

- Chiu dithit k vn khun y dm = 9000 b rng tit din ct

= 9000-500 = 8500 (mm)

- Chiu di thit k vn khun thnh dm : 9000 200 = 8800 (mm)

- Chiu rng thit k vn khun thnh dm : 400 100 - 150= 150 mm.

=> Kch thc dm cn thit k :


52/59



y dm : 8500 x 200

Thnh dm : 8800 x 150

- Chn vn khun :

- Ta chn:

3 tm HP-18202 tm HP-1520

3 tm HP-1815

2 tm HP-1515

1 vn khun thp 400x150x55


* Tnh ton cho vn khun y dm

Gi s cc tm vn khun lm vic nh 1 dm lin tc, ta chn tm vn khun c tit

din ln nht tnh ton.

S tnh cho tm vn khun HP-1820 tnh ton

L

L

L

q

M= ql /10

2


J = 20,02 cm4, W = 4,42 cm3v g = 14,5 kg

i vi vn khun dmth ti trng tc dng ln n l ti trng thng ng: bao

gm tnh ti v hot ti:

Tnh ti:

- Ti trng bn thn ca kt cu dm: l trng lng tng cng ca b tng

v ct thp.

p1=.hdVi: = + = 2500 + 100 = 2600(kg/m3)

hd = 0.4 (m)

Suy ra: p1= 2600 x 0,4 = 1040 (kg/m2).


p2 =

= 40,28( kg/m2).Hot ti:

- Hot ti do ngi v thit b thi cnggy ra : p3= 250 (kg/m2)


53/59



- Hot ti do chn ng trong cng tc b tng th cng :p5 = 250

(kg/m2)


Ti trng tiu chun: qtc = (p1 + p2+p3+ p4).b

= (1040 + 40,28 + 250 +250).0,2= 316,06 (kg/m).

Ti trng tnh ton: qtt = (1,2.p1 + 1,1. p2+ 1,3.p3 + 1,3.p4).b

= (1,2.1040 + 1,1.40,28 + 1,3.250 +

1,3.250).0,2

= 388,46 (kg/m)



ll l

q

M= ql /102


].[.10

. 2

max nW

lq

W


lx g ttq

W.10].[ => lx g210010.4,42.102= 154,58 (cm ).


400

1][

E.J

lq.

128

1

l

f 3tc

l

fcc

=> 4003

= 2,1.

= 162,07 (cm)


Nh vy ta c lx g =900 mm, v vn khun HP-1520c chiu di nh hn HP-1820

nn ta chn lx g k vn khun HP-1520 l lx g = 1500 mm tha mn yu cu v

cng v vng.

- Tng ng di mi x gngang, ta dng 1 ct chng K-103B chng x g.* i vi vn khun thnh dm, l vn khun khng chu lc nn ta b tr cc

kp thnh dm tng ng vi v tr ca mi x g vn y dm.


54/59



u c x g vn y dm, ta b tr thanh kp vn thnh dm tng

ng.

+ i vi dm cnh 3900:

- Chiu dithit k vn khun y dm: 3900b rng tit din ct

= 3900400 = 3500 (mm)- Chiu di thit k vn khun thnh dm : 3900 200 = 3700 (mm)

- Chiu rng thit k vn khun thnh dm : 400 100 - 150= 150 mm.

=> Kch thc dm cn thit k :

y dm : 3500 x 200

Thnh dm : 3700 x 150

- Chn vn khun :

- Ta chn:

1 tm HP-1820

1 tm HP-1520


1 tm HP-1815

1 tm HP-1515


* Tnh ton cho vn khun y dm

Gi s cc tm vn khun lm vic nh 1 dm lin tc, ta chn tm vn khun c titdin ln nht tnh ton.

S tnh cho tm vn khun HP-1820 tnh ton

LL

L

q

M= ql /10

2


J = 20,02 cm4, W = 4,42 cm3v g = 14,5kg

i vi vn khun dmth ti trng tc dng ln n l ti trng thng ng: bao

gm tnh ti v hot ti:

Tnh ti:

- Ti trng bn thn ca kt cu dm: l trng lng tng cng ca b tng

v ct thp.p1=.hd


55/59



Vi: = + = 2500 + 100 = 2600(kg/m3)hd = 0.4 (m)

Suy ra: p1= 2600 x 0,4 = 1040 (kg/m2).


p2 = = 34,44( kg/m2).Hot ti:

- Hot ti do ngi v thit b thi cnggy ra : p3= 250 (kg/m2)

- Hot ti do chn ng trong cng tc b tng th cng :p5 = 250

(kg/m2)


Ti trng tiu chun: qtc = (p1 + p2+p3+ p4).b

= (1040 + 34,44 + 250 +250).0,2

= 314,89 (kg/m).

Ti trng tnh ton: qtt = (1,2.p1 + 1,1. p2+ 1,3.p3 + 1,3.p4).b

= (1,2.1040 + 1,1.34,44 + 1,3.250 +

1,3.250).0,2

= 387,18 (kg/m)



ll l

q

M= ql /102


].[.10

. 2max nW

lq

W


lx g ttq

W.10].[ => lx g210010.4,42.102= 154,83 (cm ).


400

1][

E.J

lq.

128

1

l

f 3tc

l

fcc

=> 4003 = 2,1.

= 162,26 (cm)


56/59




- Tng ng di mi x gngang, ta dng 1 ct chng K-103B chng x g.

* i vi vn khun thnh dm, l vn khun khng chu lc nn ta b tr cc

kp thnh dm tng ng vi v tr ca mi x g vn y dm.

u c x g vn y dm, ta b tr thanh kp vn thnh dm tngng.


57/59



PHN TH BA

CC BIN PHP AN TON LAO NG

1. An ton lao ng trong thi cng b tng

- Ton b cng nhn phi c hc an ton lao ng, c trang b bo h lao

ng y trc khi thc hin cng tc ny.Li qua li pha di khu vc ang b tng phi c ro ngn bin cm. Khi thi cng cc b phn kt cu c nghing

t 30 tr ln phi c dy buc chc chn cho cc thit b, cng nhn phi c dy an

ton. Khi thi cng su ln hn 1,5m phi c nh chc chn vi bm b tng vo

cc b phn cp pha hoc sn thao tc. Dng m rung m va b tng cn phi

ni t v m rung, dng dy bc cch in ni t bng phn phi n ng c in

ca m, lm sch m v qun gn dy khi ngng vic. Cng nhn vn hnh phi

c trang b ng cch in v cc phng tin bo v c nhn khc.

- Khi bo dng b tng phi dng gin gio hoc gi , khng c ng ln

cc ct chng hoc cnh cp pha.

2. An ton lao dng khi thi cng ct thp

- Vic gia cng ct thp c tin hnh khu vc ring, xung quanh c ro

chn v bin bo.

- Bn gia cng ct thp phi c c nh chc chn, nu c cng nhn lm

vic 2 pha ca bn th phi c li thp bo v cao t nht 1m, ct thp lm xong t

ng ni qui nh. Khi nn thng thp trn cun bng my phi che chn bo him trc cun my khi m my. Nn ct thp bng ti in phi c bin php phng si

thp tut hoc t vng vo ngi. u cp ca ti ko ni si thp cn nn thng

bng thit b chuyn dng, khng ni bng cch buc dy cp vo si thp. Ch c

tho lp u dy cp v ct thp khi ti ko ngng hot ng. Cm dng cc loi my

truyn ng ct cc loi thp ngn hn 80cm nu khng c cc thit b an ton.

- Khi lp dng ct thp cho cc khung c lp, dm x ct tng v cc kt cu

tng t khc phi s dng thao tc ti thiu l 1m. Khi ct b cc phn st tha trn

cao cng nhn phi eo dy an ton v di phi c bin bo. Li i li trn cc

khung ct thp phi lt vn c chiu rng khng nh hn 40cm. Buc thp phi dng

cc dng c chuyn dng, cm khng c buc bng tay. Khi lp t ct thp gn

ng dy in, trng hp khng th ct in th phi c bin php ngn nga ct

thp va chm vo dy in.

3. An ton lao dng trong thi cng h gin gio, vn khun

- Trong qu trnh thi cng khi dng n cc loi gin gio, gi th phi lm

theo thit k, c thuyt minh tnh ton c cp c thm quyn ph duyt.- Nghim cm khng c s dng gin gio gi khi: khng p ng cc

yu cu k thut v iu kin an ton lao ng nh khng y cc mc neo, dy


58/59



chng hoc chng c neo vo cc b phn c kt cu km n nhKhng s dng

gin gio khi c bin dng nt hoc mn r, khng s dng h ct chng, gi khi

t trn nn km n nh (nn yu, thot nc km, ln qu gii hn, m lt bng

nhng vt liu khng chc chn) c kh nng b trt, l hoc t trn cc b phn

kt cu nh, cng trnh cha tnh ton kh nng chu lc.- Khi lp dng h thng gin gio cn phi thc hin nh sau: dng n u

phi neo chc vo cng trnh ngay n , cc v tr mc neo phi c t theo thit

k. Khi v tr mc neo trng vi l tng phi lm h ging pha trong neo, cc ai

thp phi lin kt chc chn phng thanh trt trn ct ng.

- Tho d gin gio phi tin hnh theo trnh t hp l v theo ch dn trong

thit k, khu vc tho d phi c ro ngn, bin cm ngi v phng tin qua li,

cm tho d bng cch git .

- Vn khun s dng cho cng trnh l nhng tm nh hnh ch to sn, khi

ghp thnh khi hoc nhng tm ln phi m bo vng chc khi lp. Khi lp phi

trnh va chm vo cc kt cu c lp trc.

- Lp dng vn khun c chiu cao khng qu 6m phi c sn thao tc, khi lp

dng vn khun c chiu cao ln hn 8m phi giao cho cng nhn c kinh nghim

lm.

- Cm t, xp cc tm vn khun, cc b phn ca vn khun ln chiu ngh

cu thang, ban cng, mt dc, cc li i st cnh l hng hoc cc mp ngoi ca cngtrnh.

- Trn sn cng tc phi ghi ti trng ln nht cho php v ch c xp vt liu

ln sn cng tc nhng v tr quy nh, phi thu dn vt liu tha, vt liu thi trn

sn cng tc v tp kt n ni qui nh.

- Cc thit b nng phi c h thng tn hiu bng m thanh v ch c trt

khi cc cn b thi cng ra hiu trt. Trong thi gian trt nhng ngi khng c

nhim v khng c tro ln sn thao tc ca thit b nng.

- Ch c tho d vn khun sau khi b tng t c cng quy nh theo

s hng dn ca cn b k thut. Khi tho d vn khun phi theo trnh t hp l,

phi c bin php phng ct pha ri, ni tho ct pha phi c ro ngn, bin cm.

Khi tho d phi thng xuyn quan st tnh trng cc b phn kt cu, nu c hin

tng bin dng phi ngng tho v bo cho cn b thi cng bit. Sau khi tho d vn

khun phi che chn cc l hng ca cng trnh, khng c cp pha tho ln

sn cng tc hoc nm cp pha t trn cao xung. Ct pha sau khi tho xong phi nh

ht inh v xp vo ni qui nh ca cng trng.- V sinh mt bng cc tng sn, tp kt ph thi v vn chuyn xung thng

qua ng vi bt trnh gy bi bn v ting n.


59/59


4. An ton lao ng i vi cng tc xy, trt

- Trc khi xy tng phi xem xt tnh trng ca mng hoc phn tng

xy trc cng nh tnh trng ca gio v gi , ng thi kim tra li vic sp

xp, b tr vt liu v v tr cng nhn ng trn sn cng tc theo s hng dn ca

cn b k thut hoc i trng.- Khi xy ti cao cch mt sn 1,5m phi bt gio hoc gi theo qui

nh. Cm khng c: ng trn mt tng xy, ng trn mi xy, da thang

vo tng mi xy ln xung.

- Trt bn trong v bn ngoi nh cng nh cc b phn chi tit kt cu khc

ca cng trnh, phi dng gio hoc gi theo quy nh.

- Khi a va ln sn cng tc cao khng qu 5m phi dng cc thit b c gii

nh hoc cng c ci tin. Khi a va ln sn cng tc cao ln hn hoc bng

5m phi dng cc thit b c gii nh hoc cng c ci tin. Khi a va ln sn cng

tc cao ln hn hoc bng 5m phi dng my nng hoc phng tin vn chuyn

khc.

- Khng vy tay a cc thng, x ng va ln mt sn cng tc cao qu 2m.

- Trt cc g ca s trn cao phi dng cc kiu loi gio hoc gi theo

qui nh.

- Cm ng trn cc b ca s lm cc vic nu trn.

- Thng, x ng va cng nh cc dng c ngh khc phi v tr chcchn trnh ri, trt, .

- Khi ngng lm vic phi thu dn vt liu ngh vomt ch.

* Kt lun:

Vic cc a ra bin php bo m an ton lao ng, v sinh mi trng, phng

chy cha chy l v cng cn thit, n em li hiu qu cao trong hot ng xy

dng, tm l an ton cho ngi lao ng, v trnh nhng thit hi ngoi mong mun

v con ngi v ti sn.

Kĩ thuật thi công 1

Documents

Transcript of Kĩ thuật thi công 1