NGUYN DUY THIN

CHC CNG TRNG XY DNG

(TI LIU THAM KHO Nc NGOI)

(Ti bn)

NH XUT BN XY DNGH NI -2011

LI NI U

Cun sch "T ch c cng tr ng xy d n g "cu n g cp cc kin thc c bn v phiig php t chc, b tr mt bng thi cng mt cng trinh xy dng, ngai ra n cn thng tin cho ngi c nhng tin b k th u t v th i cng xy

tdng, t chc khoa hc lao ng, lp k hoch tin thi cng..., nhng vn 1 t ra hng ngy trn cng trng ca mt ngi ch huy th i cng.

Ni du n g sch gm 8 chng:

Chng 1: X y dng nh v cng trinh cng cng - Vn t chc x nghip.Chng 2: N h ng nghin cu s b m cng trng.

Chng 3: B tr chung m t bng cng trng.

Chng 4: B tr cc thit b chnh.

Chng 5: T tng ch o trong t chc lao ng.Ch ng 6: S p h i hp cc cng trng.

Chng 7: Kim tra cng trng.

Chng 8: T chc cng vic.Cun sch ny nhm vo cc i tng: sinh vin theo hc ngnh thi cng cng

trnh cc trng i. hc Xy dng, i hc Thy Li, i hc Giao thng Vn tti..., cc k s cn b k thut thit k v thi cng cc cng trnh xy dng.

N goi ra, c th lm ti liu tham kho cc trng Trung hc, Cao ng c (o to chuyn ngnh xy dng.

Do c im xy dng mi cng trng c mt c th ring, nn nhng m guyn tc nu trong cun sch v mt t chc c th vn d n g mt cch linh ihot m c li cho tng cng trng, tng ni gii quyt thch hp v hiu (qu nh t cho mi cng tc.

Tc gi m ong mun cun sch ny n vi c gi l m t ti liu tham kho (C ch gp phn vo vic t chc cng trng xy dng c tt hn - Mt lnh wc thc s l va rng, va kh.

M ong bn c ph bnh, gp cho cun sch ny.

l c gia

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XY DNG NH V CNG TRNH CNG CNG - VN T CHC x NGHIP

Chng 1

1.1. XY DNG L MT NGNH CNG NGHIP

Ni n cng nghip ngi ta lin tng n nh my vi cc thit b lp t c nh, v ngy cng c t ng ho, trong khi ngnh xy dng gi cho ta s lm vic ngoitri trn cc cng trng c tnh cht tm thi v t c c gii ho.

Vy, th no l mt ngnh cng nghip. N bao hm ba mc tiu:

- To ra cc nguyn liu nh trong cng nghip luyn kim ngi ta tuyn qung to ra st thp. Cng vy trong xy dng phi khai thc cc m ct, si to ra vt liu cho xy dng.

- To ra cc sn phm ban u, nh luyn kim cung cp nhng tm st, thp; trong Ky dng c nh my sn xut btng cung cp cho cc x nghip sn phm btng c sn, cc loi btng ti.

- To ra cc sn phm c hnh dng nht nh, nh cng nghip ch to t t cc tm thp hnh, vt liu tng hp... v, trong xy dng cng nhn s dng cc vt liu, kim loi, btng c cc cng trnh nh , bnh vin, ng s.

Mi ngnh cng nghip u nhm vo rrmc ch cui cng l tao ra sn phm bn cho ngi tiu dng.

Trong xy dng mi cng trnh hon thnh u c mt mc tiu s dng: nh , cc cng trnh cng cng nh trng hc, bnh vin, cng trnh cng nghip v thng mi, cu, ng v.v...

T phn tch trn c th kt lun rng xy dng thc s l mt ngnh cng nghip v n lm ra ca ci cho x hi thng qua cc sn phm ban u v bn thnh phm. Nh vy c s khc nhau gia xy dng v cc cng nghip khc: n khng phi l mt nn sm xut c t chc mt cch hon chnh, cng nghip ho cao nh l sn xut t c h n g hn. L do th c nhiu, v cng ngh ip xy dng c n h n g k h k h n thng khng c bit trc nh cc ngnh cng nghip khc, chng hn:

(1 ) N h n g thay i khc vi ban u c a ch c n g trnh, thng c n h iu thay ii, sa cha thit k trong qu trnh thi cng.

(2) Trong xy dng c nhiu loi cng trnh ph thuc vo a im xy dng.

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- Kin trc s phi ch khch hng chp nhn v h thng t nhiu iu kin chcnng cho cng trnh v c ti hng trm loi nh .

- Phng thit k th hin d n theo cc s liu thc t.

- Cc nh o u i ig ng vt t d xut nhiu loi vt liu c trn 200 loi ngi v 1200loi van nc...

- Cc nh thu s thc hin d n, nhng cc conu tnrng c nhnu diu kin tir nhin rt khc nhau, i hi cc bin php thi cng rt khc nhau:

- Cui cng vic iu hnh thi cng vi nhng quy tc ca n, khng ngng phi thay i cho ph hp.

(3) Cc phng thc tip cn th trng cn lc hu: Gi bn c tha nhn trc khi sn phm ch to, trc khi x nghip nh gi thnh thc s ca n - hoc vic nh gi chnh xc gi v cc phng thc thc hin l kh khn v da trn cc gi thit c th b thay i khi thi cng.

Kiu dch v nh vy bt buc x nghip xy dng phi c s phn on, d bo nghin cu trc v c hng kim sot thng xuyn trong qu trnh thc hin xy dng.

(4) Cc cng trnh thng khng lp li ging nhau, khng th c tnh lin tc.

(5) Thi cng cng trnh c phn ra thnh tng phn on cho nhiu x nghip thc hin tng loi cng vic khc nhau trn cng trng.

(6) Tnh khng n nh ni lm vic v s bin ng v nhn cng to ra s bt li: s hot ng gin on vi nhng trm lp t tm thi, ko theo l to nn nhng thi gian khng sn xut.

(7) Sn xut c thc hin ngoi tri, bt k thi tit no tt ca nhng ph thuc trn cha ng nhiu diu bt ng xy ra v cc ri ro c th n vi cng nghip xy dng. Tuy nhin, ngnh xy dng t my chc nm qua d t nhno bc tin ln lao trong vic cng nghip ho.

1.2. CNG NGHIP HO NGNH XY DNG

S chm tr trong vic thc hin cng nghip lio ngnh xy dng c lin quan n phng thc sn xut ca n.

Nh vy th no l cng nghip ho ngnh cng nghip xy dng. l c s n lc lm tng nng sut lao ng bng cc phng php hp l ca t chc khoa hc v lao ng. i vi ngnh xy dng c th khi qut nhng vn sau:

- S dng cc cu kin c sn v p dng khn kho cc kiu mu; p dng tnh lp li v tnh lin tc l nhng yu t c bn.

- C gii ho trong xy dng bao gm vn chuyn, lp ghp cng trnh, lp t thit b..., cc cng tc nng nhc.

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Mi nn cng nghip tin b dc c trng bi tnh n nh ca v tr lm vic (vi cc i th c hun luyn lnh ngh).

Mc du trong my chc nm qua nng sut ca cng nghip xy dng tng ng k, song vn cn mt khong cch so vi cc ngnh cng nghip khc. Nh vy trong nhng lnh vc no c th thc hin c cng nghip ho mnh m trong ngnh xy dng. Cn c vo nhng tin b t c ta c th c kt c mt s vn sau:

- Trc ht, vic t chc cc x nghip xy dng th mi chc nng nhim v phi tht r rng, nn theo hng chuyn mn ho cc cng trng, nhn mnh tnh lp li v lin tc ca cng vic;

- Chun b tht t m chi tit cc C112 vic lin tc sau khi nh r cc cng tc c bn;

- C gii ho cc cng trng tng nng sut lao ng, gim s mt nhc cho ngi thi cng.

Nhng mi mc tiu trn ch c th t c hiu qu y khi cc cn b nhn vin, k thut vin tip thu c cc nguyn tc ca vic tng nng sut, tng sn lng v tun theo nhng nguyn tc cua t chc khoa hc lao ng.

1.3. C CU NGH XY DNG NH V CNG TRNH CNG CNG

Thng thng trong ngh xy dng ngi ta chia ra lm 2 lnh vc. Cc cng vic thuc v cng trnh cng nh cc nh my, cc vn phng hoc kho tng, ca hng thuc v cc cng trnh nh. Cn cc cng vic ca cng trnh cu, cng, p, ng thng thuc v cc cng trnh cng cng.

Nhng v nguyn tc mi cng vic c gi l cng cng khi tin hnh cc ho ng v bt ng sn c mc ch phc v li ch chung v c thc hin bi mt t chc c chc nng dch vu cng cng, n dc quy nh theo lut.

Mt c quan c chc nng Xiy dng nh cng cng, cng thc hin chc nng ca cng trnh cng cng, nhng l x dng nh.

Nh vy cng trnh xy dng nh c lin quan n s tin ch ca con ngi. D khch hng l cng hay t, n u to ra cc c s bt ng sn cn thit cho i sng x hi (nh ca, trng, bnh vin) v cho di sng kinh t (nh my, vn phng, ca hng, kho tng v.v...);

Cc cng trnh cng cng lm bin i su sc trng thi t nhin ca mt t v a im xy dng, cn thit cho cc ngnh cng nghip v cho vn ti nh cc con ng v cu, cc ga sn bay, ng st, cc bn cng v u tu, cc p nc, mng li dn nc, thot nc, ng dy ti in... *

Trong xy dng cn c khi nim v xy th v cng tc hon thin. Khi nim hon thin thng c hai loi cng vic kt thc cng trnh: lp t thit b (ng nc, si, in, v.v...) v cng vic trang tr (sn, h thng ca, cc lp lt nn, granit, thm, v.v...) cn v khi nim xy th, v mt k thut n l cc kt cu chu lc v khng chu lc, hnh thnh nn cng trnh.

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C nhng x nghip c chuyn mn ho trong cc cng tc v t (cng tc t), cng tc tiu thot nc (mng li tiu nc sinh hot, nc ma) cc ng dn nc (mc ni ng ng v cc cng t nc), ng dn ga (cc nhnh pha ngoi), in (h th), cc ng ra vo v ng ni b cng trng (ng cho ngi i b).

1.4. NHNG NGH NGHIP KHC NHAU V NGUI THAM GIA XY DNG

Lc u d n xy dng do ch u t xut. Ch u t c th l mt c nhn, m! doanh nghip hay mt t chc thc hin k hp ng vi nh thu v cc nh t vn. Ch u t a ra tin cc cng vic m bo ng trnh t. Ch u t chon v ch nh cc k thut vin, cc kin trc s v k s gii thit lp v khi ng d n; thc hin cc cng vic xy dng cng trnh l cc nh thu.

1. C h cng tr n h (ch u t)

l ngi vch ra cc k hoch cng vic thc hin. Thit lp cc nghin cu v k thut, kt cu,cc mt kin trc, ti chnh, d ton, xin php xy dng, chun b h s thu.

Ch cng trnh phi tin hnh mi thu, hng dn v gim st thc hin cc cng vic, phi hp v gim st cc iu quy nh trong lut php, quy tc, cc tiu chun kthut, cc iu kin ca th trng; ra cc lnh bng vn bn (cc lnh cng vic); quantm n ni quy cc cng vic sau khi xc minh cc bo co v nghim thu.

Thng thng c th thu mt kin trc s lm vic cng vi b phn k s t vnlm i din cho ch u t. Ngi i din cho ch u t cn phi sa cha nhng iu xy ra do li ngh nghip nh: s chm tr, thay i k hoch khng c s thng nht tnrc, kim tra qu trnh thi cng vi s thng nht trc, kim tra khi vt d ton qu mc quy nh...

2. Cc cn b k thut chuyn ngnh

Trong s phi k n:

a) Nhng cn b trc a tin hnh lp lng mt bng, ton c v cao c do kin trc s yu cu v cc yu cu o c khc do x nghip thng thu ngh.

b) Nhng k s chuyn ngnh xc nh chi tit cc im rt c bit thuc d n m kin trc s yu cu:

- Mt bng thc hin phn btng ct thp:

- Thc hin cc lp chng thm.

- Nhng vn v m hc, cch nhit.

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- Nghin cu nn mng.

- Hiu qu v mt kinh t.

- Lp k hoch thi cng v b my cng trng (cc k s t vn) trc khi khi cng. Cc k s t vn gn b vi ch cng trinh phi qua mt hp ng kinh t theo cc iu quy nh ca php lut.

3. Nh thu

L bn chu trch nhim thc hin cc cng vic thi cng sau khi hp ng k kt trn c s thit k c duyt.

Ho bn cng trnh lm ra ly mt gi tr quy nh trc (trong hp ng nhn thu cng trnh). Nh thu c th l mt hp tc x xy dng, mt s i th, x nghip hay cng ty xy dng... Nh thu chu trch nhim thi cns cng trnh ng tin ca ch u t, chu hon ton v cht ln S cc cng tc xy dng, k c trong thi gian bo hnh cng trnh.

Ngh ca nh thu c th i vo chuyn mn ho trong mt hoc nhiu lnh vc hot ng. Nh thu c th thi cng ton b cng trnh v cng c th gi thm thu ph lm mt s cng tc xy dng ngoi chuyn mn ca mnh. Nhng thu ph ny l nhng x nghip chuyn ngnh. H lm vic theo hp ng vi thu chnh (tng thu), v mt php l h khng lm vic trc tip vi ch u t.

1.5. T CHC, X NGHIP XY DNG

Do tnh phc tp ca cc cng trnh v tnh a dng v ngnh ngh xy dng nn cn ihit phi:

- Chia cng vic theo cc ngnh chuyn mn hot ng.

- Phn nh theo cc chc nng nhim v cn hon thnh.- Tnh chnh xc v gii hn trch nhim cho tng cng vic.Tuy vy vic t chc mt x nghip cn tuy thuc vo mt s nhn t:

qun s, cc lnh vc hot ng, tnh nng ng ca th trng

1. N hng chc nng, nhim v ch yu ca x nghip

C su chc nng ch yu sau:

- K thut: chun b, t chc, thc hin tin thi cng cng trnh;- Thng mi: mua v bn;

- Ti chnh: khai thc v quan l cc ngun vn u t;

- K ton: kim k, tng kt ton, gi thnh, d bo v gim st cc khon chi tiu;

- An ton: bo v ti sn v con ngi

- Hnh chnh qun tr: chc nng qun l i vi con ngi, phi hp hot ng gia cc b phn.

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Chng ta nn lu c hai nhim v mi xut hin trong thi gian gn y m hin cn t n trong cc x nghip xy dng. l quan h con ngi v cc quan h x hi; cc chc nng nhim v mi ny mi ngi th trng cn phi bit r nhng nguyn tc ca n.

2. So t chc

Do tnh phc tp v vic phn chia nh b phn theo chc nng nn cn phi din t mt cch r rng c cu t chc theo dng khi qut, s lm r c s phn chia cc nhim v v lm r trch nhim tng lnh vc hot ng ca cc b phn c th bit ngay c: ai lm ci g v ai iu khin ai.

Mt s t chc phi ch r c cc mi lin h gia cc b phn. Di y xin gii thiu vi s tham kho:

b)

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Hnh 1.1: S d t chc mi x i nghip xy dng loi nh

Hnh 1.2: S d t chia mt x /ti>hip .V/V dO h i 'a

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3. M i lin h gia cc b phan

S t chc lm r trt t cc chc nn qua mi lin h dc: l cc mi quan h cho php 'hoc lnh do. Clne hn nh trng b phn nhn cc lnh ca ch huy trng cng trnh v bn thn li lun th theo Gim dc x nghip.

Vic tp trung cc quyt nh cp cao nht thng ko theo nhiu bt tin nh thiu thng tin v cc s liu tlc t, chm tr troim vic chp nhn cc quyt nh khi khn cp, iiim bt tnh sim to ca cn b k thut thi cng trc tip.

Cc b phn cim klim th lm vic dc khi tch ri cc mi lin h ngang, v n s lm r c cc mi lin h chc nim v phi hp cn thit khi mun c tinh thn lm vic theo kp mi khu tronu thi cim. C nh vy cc quyt nh mi kp thi cho cn b k thut da ra nhim uii php thc t. Qua qu trnh nghin cu chi tit mi b phn, ta s nh r cc mt ch yu cua cc mi lin h ny, c th hin qua cc hi ngh, thng k gia cc irnc b phn.

4. Vai tr ca cc b phn ch cht

(1). Tng gim c: Trch nhim ny c chi nh qua Hi ng qun tr.

Tng gim c nh ra cc mc tiu v ra cc quyt nh, la chn nhn s, phn cng cc nhim v qua vic phn nh v eii hn quyn lc, trch nhim. Tng gim c gim st mi mt hot dnii v c trcl nhim nm dc cc kt qu ca cc cng trng, ua ra cc k hoch, cc lnh liiim cnu vic, cc d bo chi tit v ngun thu... T ns gim dc lm trim ti clio mi tranh chp xut hin gia cc b phn, c mt th k v ban gim c gip vic.

(2) Gim c iu hnh chu trch nhim dn thun v hnh chnh v thng kim c c n h im v ti ch nh , k ton, (liuoig n v un ton, bik m s phi hp th n g sut

trong dn v (cc thng l, bo co, hi nul).

di cu hnh cng trng cn c cc b phn:

Mt th k chuyn phn phi v ui cong vn th t, lin lc cht ch vi tng gim c, phi hp vi cc b phn khc v m bo cc mi quan h vi bn ngoi.

B phn nhn s hoc b phn x hi chm lo cc vn thu lao ng, cc hp ng lao ng, xa thi, k khai cc tai nn lao im, mt s x nghip cn c nhn vin an ton lao ng bn chuyn trch. B phn ny thng l k ton kim lun i vi nhng x nghip nh.

B phn k ton chu trch nhim chi tr, k ton chung, k ton phn tch cc cng trng, lp bn k khai ti chnh. B phn ny lin h gn b vi mi b phn khc.

Mt b phn php l chuycn lm cc hp dng, cc thng lng vi khch hng hoc tho thun vi cc x imlip khc, moi vn vc tranh chp (phng nga mi i

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u, gii quyt tranh chp). Thng thng, trong x nghip ch cn mt cn b t vn php lut gip v cc mt php l.

B phn thng mi nm tng qut mi vn , nhim v ch yu tp trung vo:

- Thm d cc cng vic thng qua tm hiu bn ngoi x nghip, phn tch danh sch mi thu, qua a ra cc i sch.

- Thng lng cc cng vic vi khch hng qua cc d n (pht hin cc iu khon mp m hoc ti ngha);

- Nghin cu v gi th trngjphi hp vi phng kinh t c c phng n hiu qu.

- Thit lp cc hp ng mua vt t, thit b, vt liu xy dng.

(3) Gim c k thut

C chc nng khai thc gim st cc hot ng k thut ca x nghip v v vy phi lun nghin cu, thc hin v kim tra cc cng vic. Cc chc nng trn da vo cc t chc chuyn mn sau:

Phng k thut c trch nhim sau khi tnh ton hp l, thit lp cc mt bng thi cng (cp pha, ct thp, lp rp, sn xut cu kin...) xut pht t mt bng kin trc.

Phng ny cng tham gia vo vic thit lp h s thu p ng cc mi thu hoc nghin cu cc d n tin kh thi i vi cc phn m x nghip trc tip thc hin. Lin h cht ch vi phng th nghim v cc t chc kim tra cht lng.

Phng nh gi v hp ng. Phng ny chu trch nhim a ra cc con s, cc hp ng theo k hoch, kim tra cc nh cung ng v cc thu ph, son tho cc bn k hng ngy, thng k cc cng vic hon thnh hng thng v vit bo co. Do n phi lin h vi b phn k ton, vi tng cng trng cung cp cc yu l cho bn k hng ngy, v cc ho co thng nht ca cng trng;

Trong giai on u thu, pliim ny chu trch nhim thit lp nn gi thnh ca gi thu (d ton, c lng gi) v s dng cc biu gi ca cc cng trnh hon thnh tnh gi thu. Trong mt s x nghip, cng vic ny c giao cho mt nhm cliyn gia xc nh gi thnh.

Phng thi cng c trch nhim iu ng v m cc cng trng, tin hnh thc hin cc cng vic theo k hoch c giao, theo di cc tiu chun k thut; gi c, tin c quy nh. Kim tra, kim sot din bin cc cng vic v chu trch nhim p dng cc ch dn k thut v cc quy nh v v sinh v an ton lao ng. N c quan h vi mi b phn khc ca x nghip cung cp mi vn d trong qun l: chm cng, bo co hnj_, ngy, cc phiu cung ng, quan h vi ch u t, cc nh cung ng, cc b phn k'.c phi hp.

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(4) B phn vt t, thit b

B phn ny khai thc qun l vt t, thit b, chu trch nhim lu tr tm thi, vnchuyn, bo qun v sa cha cc thit b ang hot ng ca cc cng trng. Cc

nhim v ny l:

- Cp nht cc phiu lu ca cc kho vt t, thit b.

- M lio vt t theo cc phiu s dng.

- Lp k hoch s dng, kim tra nh k.

- Qun l cc hot im vt t (nhn cc d tr ca cc b phn lin quan v t chc quay vng xe t);

- Lp t thit b thi cng trn cc cng trng.

B phn ny c th phn theo nhm, ngoi nhm c kh, cn cc nhm chuyn mn (t sn xut cp pha v dng c c bit (mc, st, rn).

(5) B phn ph tr

Tu theo x nghip v cc hot ng ca n, cc b phn ph tr c th tn ti theo (lng c lp v chu s lnh o trc tip ca gim c. V d:

B phn lm cng vic bo dng, sa cha nh xng.

- Lm nhng cng vic rt khc nhau nh vic tu b cc khu nh ca x nghip.

- Bo dng nh k khu nh mi.

- Bo dng nh k cc khu hnh chnh ca x nghip.

y l mt b phn phc tp, nhiu vic vt, ngi ph trch phi l ngi nng ng v c kh nng tm ra cc giai php hp l mt cch nhanh chng.

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C hng 2

NHNG NGHIN c u s B E M CNG TRNG

2.1. CNG TRUNG V VAN t h a u

(1) Th no l mt cng trng? l ni m ngi ta xy dng v thi cng cng trnh c d kin trong mt thi hn bit trc: mt cng trng b gii hn v thi gian v khng gian v thc t lun lun khc vi cc cng trng trc. Nh vy cn phi suy ngh nghin cu k vn t chc cho ph hp vi tng loi cng trng.

(2) Mi thu l s? thu l d an oc a ra bi ch CI1 2 trnh cho cc nh thu bit thng qua th mi thu. l mi cc ng c vin thc hin cc cng vic ca d n.

i vi cc d n c vn u t tng i ln ch cng trnh km theo h s mi thu l mt thng bo nu ln:

- Cc khuyn ngh chung, trnh t hnh chnh lin quan n cng trng.

- Cc bin php t chc chung ca cng trng.

- Cc rng buc lin quan n bo v mi trng.

- Cc rng buc lin quan n vn vn ho, x hi a phng.

- Cc con ng s dung tnrc khi m cng trng d c th vo cc khu cng nhn vin, cng nh cc kh nng m bo v sinh cho cng trng.

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2 vng t ct chng v dm 1 vng t cp pha hp nh v (tho cp pha trong 3 ngy)

Nhn cng cn thit:

Thng thng 80ph/m2 cp pha, ct thp, btng, tho, > 2 Cp pha. Nh vy thc hin c mt din tch 150m

trong 3 ngy th k hoch trn phi cn 150x1,33------------- = 8 n 9 ngi 4 hoc 5 th phu

3 x 84 hoc 5 th chnh

Lp chu trnh cng vic cn thit phi bt u t vic phn nh cng trnh thnh nhng loi vic khc nhau hoc cc nhm cng vic theo trnh t lgch hp l ca qu trnh thi cng. Chng hn c th phn ra cc giai on sau:

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- Cc cng vic lm nn, mng.

- Phn trn cng trnh.

- Cc cng vic hon thin.

i vi mi loi cng tc ta li chia nh theo tng vic c xem nh cc n v cng vic.

Mi mt vic ta li phn tch ra mt s loi nhim vu c th giao cho tng nhm chuyn mn lm. Vic lm ca mi nhm s m bo lin tc trn ton cng trnh, nhm t c tnh lin tc hp l.

Mi mt loi cng vic (cp pha, t ct thp, xy...) d dng o v c giao cho mt i phi h thng ho lp nn bn d ton. Nh vy ngi ch huy cng trng c th thc hin vic kim tra tin thi cng d quy nh thng qua cn b k thut ca lng i.

Cc k thut vin thc hnh khng c do d, tranh lun v phng php thi cng. Cn phi d on v gii quyt trc nhng kh khn c th gp phi, phi lm cho h l cc iu kin k thut bng cch lp cc phiu chi dn nu r chi tit chng trnh ca lng ngy trong chu trnh lm vic v cho mi loi cng tc. Trong cc phiu ny hng dn ngi tha hnh cc chi tit lm vic, cng c, thit b v cch sp xp cng vic. Chng cng c th km theo k hoch ghi li giii thch, thi gian quy nh v tn ngi chu trch nhim a ra nhng chi dn ti hin trng. Cc phiu ny c gi cho k thut vin tha hnh c lin quan n cng vic phai lm nh btng, li cn cu, hoc gi cho i trng.

Cc bn v thi cng: d l cng vic ca phng nghin cu hin php thi cng, cn phi lu : bn v phi r rni, chnh xc d cho nhng ngi th c; kch thc bn v nn gim nh ph hp vi vic c trn cng trng thng dng kh 420 X 297 c lli gp vo cun s d d dng kini tra khi cn. Bn v l ngn ng chung cho tt c mi ngi tham gia vo cng tc xy dng v phng nghicn cu bin php thi cng thit lp ra cc bn v thi cng c mt phn trch nhim trong sn xut cng trng.

Cc h s lin quan n nhn cng:

Chng ta bit rng cng trnh phi phn nh ra theo tng loi cng tc v bn thn cng tc li c chia theo tng giai on v tng nhm cng vic tng t thc hin mt tin nht nh trong thi hn hp im. c th phi hp nhp nhng cc giai on v khi lng ph hp vi vic thi cng nhanh chng, tit kim nhn lc, cn phi tin hnh theo mt tin trnh sau:

Tnh ton tng s gi cng, tc l tng s g cn thit c Th thc hin c mt cng tc trn cng trng.

Chng ta bit rng mi mt n v cng tc ca bn d ton tng ng mt thi gian nht nh. Tng s thi gian hon thnh mi cng tc trn cng trng chnh l s gi cng cn thit thi cng ton b cng trnh. l s liu c bn :

29

- Tnh d ton nhn cng, ton b s tin b ra tr long cho cc loi cng nhn trn cng trng.

- Xc nh tng cng nhn v phn b cng nhn thnh cc i chuyn mn.

- Thit lp cc mi quan h thy r c vic di chuyn v nhn cng trong tng giai on thi cng ( c d kin trc).

- Kim tra nng sut lao ng ca tng i th trong thc t.

iu ho nhp thi cng v s lng cng nhn trn cng trng: cho d phng php tnh ton no c s dng th ton b cng tc trn cng trng phi c th hin bn lp k hoch "nhng khu chnh" lm r vic iu ng cc i th. Qua cho ta mt hnh nh trc v s iu ng phng tin vo cc cng tc vi cc nhim v lin tc hay chng ln nhau v nhng ngi iu ng n c cng mt thi gian khng, s th v nhp thi cng c ph hp, chng cho, nhau khng?

Vic tnh ton k bn lp k hoch chung ny s thy r c nhng kh khn thc t iu ng cc i th v cc thi k cng vic gim phi chuyn th n cng trng khc.

D kin din bin tnh hnh thc t tin ti ti u ho vic iu ho nhp thi cng l rt cn thit i vi cc cn b k thut c trch nhim ch o v c trch nhim v nng sut lao ng ca cng trng, trn c s tng hp c cc bin php hu hiu cn bng qun s lao ng trn ton cng trng.

Cc h s khc cn cho vic iu ho nhp thi cng l:

- Lp th v tuyn dng v di chuyn lao ng lm r s bin ng ca qun s trong qu trnh thi cng. th ny c biu th nh trn hnh 2.2.

Thi gian thi cng ca cng trng : 45 tun

Hnh 2.2

30

- Cc th lu tch gi nhn cng lm r s lng nhn cng, hng tun, hng thng d kin phi c. th n gin ho thi gian lu tch thu mn nhn cng nh biu th theo hnh 2.3.

- S v t chc cng trng, bng tng hp nu r trch nhim mi cp ca Ban ch huy cng trng v nu s lao ng ' tma b phn sn X ut.

Tm li vic tnh ton k hoch nhn cng l nhim v rt tinh t, phc tp, ngi ch tr phi th hin mt tinh thn sn sng i vi mi bt chc c c mt k hoch nhn lc tt, chng hn nh tuyn chn cc i th lnh ngh; s thay i gi theo ma; nhng bt thng v thi tit; m au, thai nghn, ch i vt t, thay i thit k trong thi cng...

Cc h s lin quan n qun l cng trng: ngn sch d kin v kim tra ngn sch. Khi nghin cu v d ton ta xc nh c khon tin tra n thun cho nhn cng v vt liu, cc chi ph ca cng trng v cc chi ph chumg, chi ph d phng... N hnh thnh tng gi tr ca gi b thu. thc hin vic thi cng lin tc v thanh ton ngay khi m cng trng trong vic chi tr lng cng nhn v cc ho n vt liu, cn gii quyt vn ti chnh ny v nh vy phi bit trc tng thng c nhu cu v tin mt.

D bo hng thng v chi tiu. Cn c vo khi lng cns tc hon thnh trong ihng c k hoch d bo chi tiu v tin lng, tin mua sm vt liu xy dng, vt t, thu my thi cng... ca tng thng. Ngoi ra phi d tr chi bt thng, s c tnh ihm 5 - 10% chi ph hng thng.

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Chi ph cng trng v cc chi ph chung c xc nh trong thi gian nghin cu d ton, c th tnh bnh qun hng thng trong c thi gian thc hin hp ng thi cng cng trng. Vic d bo cc chi tiu c th xc nh nhanh hn bng cch tnh gn ng so vi cc cng trng hin c xy dng xong.

D bo cc ngun thu: Cc ngun thu cn c vo hp ng thi cng v phng thc thanh ton vi ch u t. C th thanh ton theo tng t thi cng, hay theo tng qu.

Lp biu cp ti chnh: V cc ng chi tiu ]u tch v ngun thu nhp lu tch s lm r c nhu cu v ti chnh (xem hnh 2.4). Ta c th vch y tnh hnh qun l d ton theo cc ng cong l thuyt vi chi tiu thc t (cc bng tng kt nhn lc vt t, my xy dng... hng thng) v tnh hnh thu thc t; vic so snh gi l thuyt v thc t cho php nhng cn b c trch nhim a ra nhng quyt nh x l kp thi.

Hnh 2.4: Biu cp ti chinh

32

(8) Cc h s lin quan n mt bng cng trng:

l s chun b chi ti tng giai on trn khu t xy dng, giai on lp t in nc cn thit cho thi cng, b tr tng mt bng cng trng va phi lm trc khi m cng trng. Ti liu c bn Irong vn ny l mt bng qun l tng qut ca cng trng, b tr cc khu t. lp rp thit b, vt liu, dng c, ln tri, nh kho.

(9) Cc th thc phi hon thnh trc khi m mt cng trng:

- Nhn mt bn sao v giy php xy dng t ch cng trinh.

- Thng bo ngy ng th cng trng.

- Cc giy php v ng vn chuyn vt t, thit b.

- n xin php lp t cc cn cu tront c ghi cc c trng k thut ca cn cu. ng nhin phi km theo mt bnh o c t l 1/500 ghi ch mi mt hot ng ca cn cu cng trng.

Cc vn chuyn c bit n cng trng cc my mc nng hoc cc vt khng th chia nh c, kch thc cng knh cng phi xin php (siu trng, siu trng).

Cc vn c lin quan n h tng, vic mc ni khc, cn phi tip xc trc (ngay khi thng thu) vi cc c quan:

- Cng ty cp nc, v ng nc thi cng v sinh hot cho cng trng.

- Cng ty in lc cp in hoc di chuyn ng dy khi lm nh hng n tm vi ca cn trc hoc n vic lp t my mc sau ny.

- Cng ty bu chnh vin thng lp t in thoi, hoc chuyn di trnh nh hng n cc my nng cu.

- Giao thng cng chnh xem xt cc ng thot nc, mi trng.

Chun b cc s sch: tru s c s nht k cng trng.

- S tr lng.

- S theo di tai nn lao dng v cc bnh ngh nghip.

- S theo di bo dng v kim tra my xy dng- S thanh tra lao ng.

- S qun l cc lao ng nc ngoi.

Cc tm bin v quy ch c treo ngay khi m cng trng:

- Ni quy cng trng

- Tcn v a chi ca cc thanh tra lao ng chu trch nhim gim st cng trng.

- Phng chng chy n cu ho.

- Cm vo cc ni nguy him.- Tm bin ch to cao > 8cm ghi r: tn cng trnh, ch u t, n v thit k, nh

thu chnh, thu ph, giy php xy dne s...

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Chng 3

B T R CH U N G M T BANG c n g t r n g

3.1. THIT LP MT BNG CNG TRUNG

1. M c ch

Mc ch c bn ca mt bng chung l c th a vo thi cng nhanh chng theo hp ng, cho php khi nq cc cng trnh sn xut v c nhng iu kin tt nht v nng sut lao ng. Nh vy phai:

- Chun b cc ni tip nhn: lao ng, vt t thit b (cc din tch lp t), vt liu xy dng (khu vc lu gi, kho tng).

- D kin cc nhu cu tin hnh cng vic mc ni (in, nc v.v...) giao thng ni b, m bo an ton cho ngi v xe my thi cng.

Tm li, cn phn tch cc khong khng gian cn thit ca khu t xy dng vi hot ng cng trng phc v tt cho thi cng cng trnh.

Cc h s u thu u c phn m t lin quan n vic b tr mt bng cng trng, v mt bng ny dc chp thun ca n v t vn. Phi c tng mt bng cng trng mi xin c giy phcp dng giao thng ca c quan c thm quyn, giy php lp rp cn cu thp.

Thit lp mt bng chung l mt ti liu quan trng cho chun b v cho t chc thi cng. Vic thit lp i hi phi c nhng suy ngh chn chn sau khi xem xt thit k v tham quan a im xAy dng.

Nu b tr mt bng cng Irng khng hp l s nh hng ln n tin xy dng v nng sut lao ng chung ca ton cng trng.

2. Ni dung ca mat bng chung

L mt bng tng th theo t l thch hp (ni chung 1/50) trn th hin cc cng trnh d kin xy dng v cc ranh gii ca khu t. N phi th hin c:

Ni t cn trc hoc cc loi cu: nh hng cao, ng di chuyn, v khong khng gian m cn trc lm vic (v d bn knh hot ng l 25m).

V tr v s xp t trn mt bng trm sn xut btng: my trn, khu cp phi vt liu, kho cha xi mng ng i ca bng ti.

V tr cc ni lm vic c nh: xng gia cng ct thp, chun b cp pha, gia cng , sn btng c sn.

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V tr cc ni lm vic, n ca cn b nhn vin: phng lm vic, ln tri, nh n, nh v sinh, ga ra t, xe my thi cng... phi c din tch c th cho tng loi.

B tr chnh xc cc con ng ra vo cng trng v cc ng di chuyn ni b cho xe c gii nh t, my m v cho ngi i b.

Cc ng trc cp v tiu thot nc, kh nn, in thoi, cp in thi cng, sinh ho! vi y chnh xc cc im phn phi hoc u ni.

Hng ro xung quanh cng trng.

Vng khng c g k c tm thi cng khng c php.

Cc v tr dnh cho dn v thu ph.

nh du cc cy ci c bo v ( li sau ny).

3. Bin p h p lp m t bng cng trng

Nhng ngi chu trch nhim thit lp nn mt bng cng trng tu thuc vo t chc n v thu: c th l phng phng php (nu c) phi hp vi gim c thi cng, thr.g thng l phng thi cng lp nn. Trong trng hp th hai, nhim v thng c giao cho ch huy cng trng chu trch nhim chnh

Nhng t liu cn cho vic lp mt bng chung cng trng:

- Mt bng tng th cng trnh ch r cc hng mc sp xy dng, v cc khong khng gian trng ca a im.

- Cc iu kin v v tr a im, a hnh khu t u i th buc phi chp nhn ccgii php thi cng c bit, nht l cc cng trnh xy dng dn dng. C nhng thun li hay khng nh ng s, cng trnh ngm, ng cp in, cp nc, cc bt ngsn n cn cng trng cng c th c nhng rng buc nht nh trong thi cng.

Phng php thi cng cng trnh chng hn:

- Dng cc vn khun thp kch thc ln, s ko theo mt cn trc ln hoc nhiu cn cu, tu theo tng giai ocn.

- Btng c sn trn cng trng s bt buc phi c mt bi vt liu v bn thnh phm.

- Thi cng bng th cng s dng nhiu nhn lc dn n ln tri ln, cc c s vt cht phc v cng nhn cng ko theo.

Qu trnh nghin cu v quyt nh.

- Cn phi nghin cu mt mt bng tng th c y cc khong khng gian cn thit, cc iu kin v v tr v cng tc chun b s c thc hin trc khi m cng trng. Tt hn ht l nn dng mt sa bn th hin cc m hnh vi t l, 1/100, c th hnh dung ra tng mt bng cng trng xy dng s thi cng.

35

M hnh c th l cc khi g th hin nh, khi nh, cc u my xy dng, ln tri, cc con ng, ng in, hng ro v.v... Cng c th sn theo nhng mu khc nhau tu theo tng chc nng d hnh dung ra.

- Qu trnh thit lp mt bng chng, nn theo mt trnh t sau:

Trn cng trng xy dng thng c cn cu nng l v tr ch cht cho vic tng nng sut. Tu theo s lng, tnh nng k thut v ni t chng m hn ch khng gian lm vic ca cn cu, tc l din tch m cn cu lm vic trong khng gian. Mi quyt nh tip theo u cn c vo vng khng gian lm vic ny. R rng trnh cc vn chuyn th cng lp i lp li, cc bi cha vt liu v bn thnh phm phi nm ' trong vng lm vic ca cn cu. Ngc li cc ni m nhn vin v lm vic nh ln tri, vn phng, cc xng nh cp pha, ct thp..., li phi b tr ra ngoi khu vc lm vic ca cn cu. Cn phi phn nh khu vc lm vic thnh cc vng lc nng ca cu, tu thuc vo s trng ti, nhm nh chnh xc nht cc khu vc cha vt liu khc nhau.

Nh vy th cn cu nn b tr th no l tt? Nu nh khu vc lm vic c th bao ph ton b ngi nh v u cn trc ti trng hu ch vn cn c tc dng di vi cng trng. l v tr tt nht, hiu qu nht trong khi thi cng. v tr ny s lm gim ng k thi gian quay ca thao tc nng v n nh hp l nht v dy no c th khng i. Trng hp m cn cu phi di chuyn trn cc ng ray th l gii php t nht, kh khn nht. N di chuyn nhiu trong khng gian nn bt buc phi kim tra thng xuyn con ng di chuyn v khng phi lun c thc hin mt cch chnh xc v an ton. N cn biu hin mt s cc nguy him xy ra trong khi di chuyn c trng ti vi dy cp in ko l trn mt t.

Hin nay, trn cc cng trng xy dng cn dng cn trc di chuyn bng bnh lp hoc bnh xch.

B phn th hai l sn xut btng lun c mt cc cng trng. N l mt b phn quan trng quyt nh phn ln kt qu ca ton b cng trng, nn v tr lp dt b phn ny phi c la chn hp l. My trn v cc thit b ca chng s t u? Mi mt cng trng s c mt cch b tr c th v y s xem xt cc tiu ch v cc gii php cc chng sau.

Ch bit rng hin ti c hai nguyn tc tri ngc nhau v cch b tr b phn sn xut btng. Mt mt v tr sn xut btng phi bo m cung cp lin tc, c khi tng ngy. Nh vy tt hn ht l ni cp phi v kho xi mng phi cng gn cc ng vo cng trng cng tt, nhm trnh cc thao tc khng kp thi t t vo trong cng trng, l gii php tit kim khng gian cn thit, Mt khc, btng phi a i ni cng nhanh cng tt, nu nh phi qua cn trc th my trn btng nn b tr trong chu vi lm vic ca cn cu. iu ny bt buc phi la chn cn cu c th nng u cn m va tng ng vi cng sut my trn btng. Khi btng khng phi o qua cn cu (trng hp nhiu ni phi btng), gii php b tr ni sn xut btng v tr khng nh hng n cc cng vic khc v gn ng vo cng tnrng t ra l c li nht.

36

Bin bo ng

Sn vn ghp Irn rnh

Hng ro

-------- --------V--------9-------r

X X X X X X

/ Vo \ Cy gi li

Bi cha vt liu

12m X 4,50m

ng ni b cho t

i b

- Chiu xe c

Tram sn xut b tng

Xe ben

3,20

1 2,

40

C

My nng

nn nn nn

0.0 0 D m r u

hoc

Cu c dinh ng ray

Nc

Cc dng nhnh

ng ng

hii cin

Chn di t = = = = =

Dy mm

s Tram nc-X---- X---- X--- X-

T phn phitrn ct

ng dy trn ct

Cc dng nhnh khc

H

Khi thiu ch b tr, gii php cung cp btng t mt nh my btng thng phm c th li thun li, nhng d sao cng phi d kin trong khu vc lm vic ca cn ci, cn c mt khong khng gian dnh cho thao tc cung cp btng ti vi thit b nhn btng nh phu, t ben...

B phn quan trng th ba l sn xut ct thp. l b phn quyt nh ti nng sut chung ca ton cng trng, cn phi ngh n vic t chc n mt cch hp l nht.

la chn v tr ca b phn ny, cng nh v tr ca b phn sn xut btng, v c hai nguyn tc i nghch nhau nhng t quyt lit hn, bi v vic cung ng ct thp t thng xuyn, ngc li vn chuyn ct thp gia cng l thng ngy. Kt qu l vic d tr ct thp phi trong vng lm vic ca cn cu, nhng cc b phn khc ca sn xut ct thp li phi ngoi vng ny.

Vic la chn t vn phng lm vic v ln tri cho nhn vin phi ngoi khu vc cn cu lm vic v ng thi sp xp cc ng giao thng cho xe c v ngi i b trong cng trng. Nn b tr cc ni lm vic, n bn cnh cc ng ra vo. Cc din tch nh lm vic, ln tri trn mt t thay i theo s lng cng nhn, nhng c th gim bt din tch bng cch xy dng cc tr s, phng lm vic trn cc kho hng, gara hoc dng cc ln tri lp ghp sn c th di chuyn trong qu trnh thi cng.

Cc con ng lu thng cng trc tip, cng ngn bao nhiu cng tt tu theo cc v tr la chn i vi tng b phn. Trn cng trng thng to nn mt mch lu thng theo mt chiu cho t, c th l hay nhng li chim nhiu khong khng gian. Xe th s v ngi i b c cc ng ring tng ng khng nn ct nhau mt khi c th b tr c.

Cc din tch kho cha cn b tr trong khu vc lm vic ca cn cu i vi mi vt liu v bn thnh phm cn vn chuyn. S' lng vt liu cn phi gii hn: trn cng mt khu d tr c th cha lin tc cc sn phm khc nhau dng nhng giai on khc nhau. iu ny cn phi d kin khi lp k hoch cung ng. Tn sut v s lng cung ng s l iu kin cho vic tnh din tch cha, nhng mi din tch phi c gii hn r rng, nu khng s tr nn ln xn v mi ngy qua i s ln xn cng tng.

4. Cc bin php lm r mt bng b tr chung

cho mt bng b tr chung d c cho nhng ngi s dng, cn phi c cc k hiu quy c ch r cc v tr khc nhau, hoc cc s lng. Cc k hiu ny c biu th di dng thuyt minh bng hnh v hoc bng s. Chng ta ly v d nh hnh 3.1 v bng 3.1.

5. Kt lun

Cc nguyn tc nu di y khng phi lun lun c th p dng, nhng phi vn dng vo cc cng vic t chc chung ca cng trng c xt ti nhng iu kin c th ca tng cng trng m xem xt.

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Bng 3.1. V d v cc s ch trn mt bng tng th cng trng

S Ch nh S Ch nh

1 Cn cu thp 10 Ln c cng

2 My trn btng 11 Phng kin trc s

3 Ni cha xi mng bao 12 w . c

4 Cc my nn13 n 16

Cc khu tr vt liu cho xy th v

5 Cn cu bnh xch hon thin

6 M y trn va xy 17 Kho hng

7 Khu sn xut ct thp 18 Khu tp kt vt t

8 Khu sn xut cp pha 20 Nh v sinh cng cng

9 Bi c sn 23 Khu cha t p

B tr cn cu, cng gn ni thi cng cng tt, nn b tr c nh nu nh n bao ph c ton b cng trnh thi cng.

Vic la chn cc c trng k thut ca cn cu l c bn phi ch n 3 tr s sau trn mt bng:

- Chiu di cn (bn knh hot ng), din tch qut, khng gian to iu kin cho mi s b tr khc.

- Ti trng u cu v ti trng nng ti a lin quan trc tip n cng sut my trn btng, trng lng ti a ca vt t c bit (cc tm kim loi di hoc cu kin btng c sn nng...);

- Chiu cao di mc, lir quan ti toa nh xy dng V mi trng m cn chuyn ng trn khng v cc quy nh hin c.

Gim thiu cc t vo cng trng nht l i vi loi trng ti nng v xe cung ng thng xuyn, v iu ny s phi huy ng mt khong khng gian ln v ko theo cc chi ph qun l con ng.

Cha cc vt liu, bn thnh phm v vt t cng gn cng trinh cng tt nhm gim bt vn chuyn: khu vc cn cu lm vic phi c dnh cho kh cha vt t, vt liu; khi c th s dng mt ng cng cng v mt nn nh thi cng lm bi cha vt liu.

Khi khu t trng rng ri, khng nn b tr tri ra qu mc, m phi tp trung li cho hp l khng to ra s phin toi ca cc b phn khc theo chc nng. Nh vy cho php gim c cc ng i li, lm gn li cc b phn quan trng ca cng trng Xcly d n g .

Cc ni dnh cho cng nhn i li lm vic phi m bo an ton.

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3.2. CC H S LIN QUAN N S l U NG CA CNG TRUNG

1. K hoch chun b khu t thi cng

Khi mt bng cluing c, cn phi thit lp mt s ti liu khc nhm lm d dng cho vic b tr cng trng kim tra c cc chi tiu giai on chun b thc hin hp ng.

Sa son khu t xy dng trc ht vo c khu t v tin hnh dn cc bi cy, cc cnh kh, cc ph tch, ph thi, dn v d tr lp t mu pha trn, tiu thot nc khu t. Sau chun b cc con ng ni b, lp t in nc, in thoi.

Lm hng ro ngn cch cng trng vi xung quanh.

Lp dng cc khu nh lm vic, ln tri, nh n, nh kho, gara.

Chun b cc khu vc, kho bi nhn vt liu, vt t: ng cn trc, trm trn btno, xng gia cng cp pha, ct thp.

Trng hp cn thit c th gh n vic lp t v a vo vn hnh mt khu sn xut cu kin lp ghp sn xut cu kin ti hin trng, gim c khi lng vn chuyn.

2. Cc ti liu khc lin quan n vic khi cng cng trng

Cc ti liu sau lin quan trc tip n vic ch o v khi cng trn cng trng:

Danh sch yu cu v vt liu, thit b, vt t v trang thit b cn thit khc khi cng.

Danh sch cc a ch lin quan n chi huy trng cng trng ngay nhng ngy u: cc trung tm y t v x hi, cc nh cung ng vt liu, vt t, thit b.

Cc loi s sch bt buc phi c theo lut nh.

Danh sch cc loi th chun b cho khi cng xy dng.

Bng tng hp cc loi my xy dng chuyn n v tnh nng k thut ca chng.

3. Cc ti liu kim tra

Giai on chun b nh chng ta bit, c gi tr u t cao, cho nn cn phi bit r cc ch tiu v nhn lc, chi ph lp t cn trc, lp t trm sn xut btng, a vo mt xng sn xut cu kin c sn chi ph ra sao.

Nn c mt bang ghi r cc nhim v, thi gian thc hin nhm bit c cc chi ph thc ca vic b tr, lp t giai on ny so snh chng vi tng d ton trong h s nghin cu gi v c th rt ra nhng khuyn ngh cho cc cng trnh sau.

3.3. CNG VIC LP T

Chng ta s xem xt tip vic b tr tng b phn mt trong mt bng chung,bng cch phn ra lm hai loi khc nhau:

40

- Cc b phn chung cho mi cng trng: cc khu nh cc ng qua li, cc nhnh u ni, hng ro, kho bi cha vt liu.

- Cc my nng cu, cc trm sn xut btng ct thp, cp pha v cc cu kin ca cng trnh btng d ng lc v chng ta s bn su v nhng b phn ny cc chng tip theo.

1. iu kin ca khu t xy dng

l iu kin c th p ng c cc mc tiu sau y:

- Gii to mi th gy cn tr n vic m cng trng.

- Thc hin c cc con ng ni b cho xe c v ngi.

- Lm kh khu t bng mng li tiu nc.

- Gii to lp t hu c (t trng trt).

- Bo v cc cy lu nm v cc c s cn^ cng.

Phng php tt nht lm sch khu t l dnq my xc nh cc bi cy, xc b ph tch, gc cy lu nm... c nhanh chng. Trang b thm cho my xc mt li ben co v y t trng trt trn mt v ni cha v san phng cc ni d kin lp t cng trnh tm. t trng trt s dc cha ni t cao v nh thnh ng.

M ng ni b cho xe my v cng nhn. ng cho xe t, my xy ng cn phi lm mt cp phi rng t nht l 3 n 4m, nu nh khi lng vn chuyn ln c th l mt btng atphan, phi c h thng chiu sng.

Cc con ng dnh cho ngi i b, rng t nht l,5ni, dn n cc kho bi cha vt liu, cc trm lm vic. Nu mt bng c vng b ly li, cn phi thot nc, lm kh t trc khi m cng trng. Chng ta nen quan tm n:

- Ci thin ngay nhng ni xe c va rigi i li trong ni b cng trng c an ton cao v nng cao nng lc vn chuyn hn.

- Xe c qua li cc kho cha vt liu d dng n cc a im xy dng vi thi gian t nht.

2. H n g ro v cc bin tn hiu

Cn gii hn phm vi cng trng, tc l khong khng gian d x nghip tin hnh thi cng, ng thi ngn nga s ra vo cng trng mt cch t do, cho php qun l v canh gc c, nhm bo m an ton trn cng trng.

Vic lm hng ro v bin tn hiu ca cng trng c lin quan n giao thng ni b v cc cng vic thi cng, ph d, cc b ng sn gn ng i li.

Cc cng trng ven sng hoc dc tuyn ng cng cng, phi c ro theo tuyn m b phn qun l ng quy nh v c gii hn ca khu t st cng trng. Hng ro phi chc chn v n nh.

41

to

Hnh 3.2: B tr cng trng tm trn ng cng cng

Li ra

ca

t

/ * i

/

7 / u l / /

J tL^i'V;Cng trng' ; v o ' _ . r*5

Ngoi ra khi cng trng tm chim mt phn t cng nh mt phn h ng, sn chi, bi tp:..., th nn li chiu rng va h ti thiu l 1 mt; phi m bo dng chy do ma, v bt k mt ca tiu nc no khng c nm bn trong hng ro (hnh 3.2). Cc ca hng ro cng trng phi m vo pha trong.

- M i cng trng c b tr trn phn ng giao thng u phi ro chn theo kiu hng ro ng b, c sn xen k mu trng v . Hng ro thng cao hn mt, chn hng ro c gn thm con trt d di chuyn. N c srdng nhm phn ranh gii cng trng, hoc dnh li cho ngi i b

Khi cng trng xa cc khu ng dn, cc gii php kinh t hn c th c xem xt. Chng hn nh dng cc tm li thp buc ln cc cc tiu. i vi cc cng trng ci to, sa cha mt ngoi, phi c mi che hoc cc tm bt chn khng ri vt liu vo cng chng.

Vic trang b h thng tn hiu cng trng phi tun th cc quy dinh cua cnh st, v ca c quan qun l ng b, s giao thng cng chnh.

Cho d cng trng no th cng phi c mt pan nu c im cng trng nh l bn cht cng vic, tn v a chi ch u l, tn v a ch cc nh thu, thi gian thi cng v s giy php xy dng, cng nh cc pan v an ton cng trng. "Cng trng cm vo". Ngoi ra i vi cc cng trng th cn c cc pan "li ra cho t" "ph b chn" chiu cm i... Nu cc cng vic phi chim ti int na ng t vic ngn chn khng cho qua li l bt buc.

nh sng tt c phn chim ng cng cng phi biu th theo cc nh mc sau: n treo nh sng vng, khong cch 6m xa theo hng dc con ng v lm xa theo hng ngang.

Nu cng trng chim mt phn ng cn phi t mt n nhp nhy mi gcngoi hng ro; mt tuyn n nhp nhy dt st cnh vi con ng lu thng.

Trong trng hp chn hon ton ph, th ghi "ng ph b chn" s treo cc n m u .

i vi cng trng lm ng, ta chia ra lm hai loi tn hiu;

- Loi tn hiu gn bo cho mi ngi bit qua cc tm bin "cng trng", "hn c h tc ", "ng b thu hp" v.v...

Hnh 3.3 : Tn hiu trn cnq trn

43

- Loi tn hiu ch v tr th hin s ln chim ca cng trng lin quan n khu vc cng trnh: cc ngi sao hoc ng chn c c hiu , cc pan cng vic, hng ro phn gii cc vng nguy him. Cc ng chn ny ng nhin phi sng vo ban m bng cc n mu vng, nhn r t xa 150m.

3. B tr cc nh sinh hot v lm vic

Chng ta nn phn bit 3 loi ln tri.

Nhng loi dng cho nhn vin iu hnh thi cng: cc phng lm vic cho nhng cn b ph trch thi cng (trng ch huy cng trng, cc c cng...) v cc nhn vin khc (k ton, chm cng...), phng cho kin trc s, phng hp ca cng trng, phng y t.

Loi dng cho cng nhn:- Cc phng thay v phng n ca.- Khu v sinh bao gm chu ra, nh tm.- Khu tm tr.- Ni cho thng trc bo v cng trng. Loi ln lu gi dng c, thit b vt t, t: cc kho dng c, cc nh my xy

dng, ch b tr cho my pht in, gara cho xe hai bnh, kho vt liu, kho xng.Cc quy nh chung cho khu vc ln tri cng trng ti thiu v tin nghi v v

sinh m bo cho ngi lao ng, m bo trnh c m thp v d lau chi. m bo c cc ca ly nh sng thin nhin v thng gi, ca ra vo c kho. C th lm ln tri tho lp c bng cc tm pan g hoc vn p, tm cht do. Cc tm ny tiu chun ho kch thc cho php nhiu t hp lp rp tu theo a im v tng cng dng ca loi ln tri.

Bng 3.2 cho ta tham kho mt s tiu chun v khu nh sinh hot v lm vic i vi cng trnh cng cng v nh c tiu chun ho. (Theo ti liu nc ngoi).

Bng 3.2a. Bng tng hp cc yu cu v sinh cng trng m cc x nghip xy dng phi tun th

Tm c cng trng Cc b phn bt bucCng trng c nh Cng trng lu ng phi c

Qun s: Qun s: - Ni thay qun o20 lao ng tr ln Bt k - Nc tm git

Thi gian: Thi hn - Ni n ca4 thng tr ln Bt k - Ni thc n v hm nng

Qun s: trn 20 lao ng

Thi gian:15 ngy tr ln

- Nc ung (3 lt/ngi/ngy)- Bung v sinh (mt cho 25) (khng bt buc vi cng trng lu ng)

44

Tm c cng trng Cc b phn bt buccng trng c nh Cng trng lu ng phi c

Qun s: trn 20 lao ng

Thi hn: trn 15 ngy cho ti 4 thng

- Ln khp kn vi t ct quno, bn v cc gh ngi.- T ng thc n v hm nng- Nc ung (3 lt/ngi/ngy)- Chu ra mt (1 chu 5 ngi) - Bung v sinh (mtcho 25)

Qun s: Tu theo nhu cu

thi hn: trn 4 thng

- Ln c t qun o v chu ra (1 cho 5)

- 1 h x + 1 b tiu (cho 25)- 25 xut n ti thiu: nh n- Cc vi tm cho mt s vic c hi v bn, t ng thc n v t hm n. Nc ung (3 lt/ngi/ngy)

Hng 3.2b. Cc khu nh cho ngi lao ng lu ng hoc sng tp th

Quy m cim trng Cc ln tri cn thit

Thi gian ti 6 thngQun s tu hoc t nht 20 lao ng lu ng

Cc khu nghi ngi Nh khp kn n , chun b ba n

Ko di hn 6 thngQun s lao ng: gia 20 v 50

Cc khu nh nG;h ngi Nh n , chun b ba n

Ko di trn 6 thngQun s lao ng: gia 50 v 100

Khu nh ngh ngi Nh n v nh bp Phng sinh hot chung

Ko di trn 6 thngQun s lao ng: gia 100 v 500

Nh nghi Nh n v nh bp Phng sinh hat chung Phng Y t

Ko di trn 6 thngQun s lao ng: gia 500 v 1000

Nh ngh Nh n v nh bp Phng sinh hot chung Trm y t Phng hp v c sch

Ko di trn 6 thng Qun s lao ng: trn 1000

Nh ngh ngi Nh n. nh bp Phng sinh hot chung. Trm y t thm bung y t Phng hp v th vin.

45

L cc sn chun b mt bng tip nhn, ch s dng cc loi vt liu, bn thnh phm thi cng, v cng bao gm vt t t bit v my xy dng trong thi cng. Chng ta c th k n:

- Cc vt liu: xy, cc loi gch xy, gch lt, ct, , si, dm kt, cht kt dnh, g cp pha...

- Cc bn thnh phm: cc khung, cnh ca v cc loi kho, cu kin btng, thit b v sinh...

- Vt t c bit: vn khun thp, tm cp pha, cy chng, gio thp...

- My xy dng: cc bm tiu nc, my nn kh cn trc my, trn btng, my trn va, my phun sn...

Quy m v din tch kho bi ph thuc vo khi lng v thi gian thi cng, k hoch cung ng.

Cc iu kin v a im: cao ro, bng phng, khng ngp nc khi ma to, ng vo ra thun tin.

C kh nng bc xp bng c gii.

- Nhng nguyn tc chung thit lp nn cc kho bi cha vt t thit b:

T tng ch o trong vic la chn l c gng rt ngn ln di chuyn, gim cc ln bc xp, gim sc lao ng bc xp v. Vn ny cn b k thut c trch nhim phi lu :

Cc vt liu ch to btng ti, btng c sn, cp pha cn gn trm sn xut btng.

Vt t hoc thit b nng hoc kh dng tay bc xp, s c cha khu vc cn trc lm vic.

Cc vt liu xy trt s gn a im thi cng.

- Khng chn kho bi quay lng vo to nh ang c thi cng.

- Kch thc v s lng kho bi. Cc c trng ny lin quan cht ch vi loi vt liu xy dng, s lng ca chng tc l vic tiu th hng ngy hoc hng tun, hoc ph thuc vo thi hn thi cng.

Song, cn lu tt hn ht l s lng kho bi nn hn ch v kch thc kho bi m bo khng tha v c th thay th cha cc sn phm khc theo s din bin ca qu trnh thi cng.

Cch sp xp kho bi nn lu n cc im sau:

- Cc v tr c chn phi khng cn tr, khng gy kh khn cho lung giao thng. Nh vy bt buc phi gii hn mt phn khng gian cho mi ln cht kho, ly cc vt liu trc m khng lm ln ln cc vt liu khc.

4. C c bi tr v tp kt vt t, m y m c

46

- Khng c qu tn dng ht din tch, phi cha cc li i thao tc v kim tra cc ln cha khc nhm vn chuyn, bc vc c d dng khi xut kho.

Cc c trng ch yu ca kho bi phi th hin c:

- Bt k vt liu, vt t no lu gi, khng bao gi c tip xc trc tip vi mt t nn kho bi phi sch, thng thong. Mun vy phi lm mt lp btng hoc bc k bng g cch mt t khong 15 - 20cm tu theo cc sn phm lu gi.

- Lp sn phi phng v nm ngang nhm m bo n nh ca kho bi, tr kho bi cha cp phi btng c th yu cu dc nht nh d dng chuyn vt liu vo trm trn.

Mi loi kho bi phi c ranh Sii trnh s ln chim cc lung ng ra vo ca xe c v ngi i b.

5. u v ni cc nhnh ng dn din, nc e khai thc cng trng

l trang b cho cnc tnrng cc ngun nng lng (in, kh nn) cn thit cho cc loi my xy dng hot nj, nc sn xut btng v cc loi va xy dng, nc sinh hot chung cho ton b cng trng. Phi ch c vic thot nc sinh hot, nc ma ra cng, chung ca khu vc.

l vic cho php cng trng lin lc vi bn ngoi qua in thoi (vn phng, ch u t, cc nh cung ng v.v...).

Nhng nguyn tc c bn trong vic u ni l:

- Mi ng nhnh u ni phi thng qua hp ng kinh t thc hin theo cc quy tc hin hnh, v phi c thc hin qua cc cng nhn c chuyn mn lnh ngh, nht l v in.

- Cc ng nhnh dn phi l ngn nhi v cc im phn phi phi la chn mt cch hp l nht;

- C bn k chnh xc cc dng nhnh chn di t phi c lp nn khi vic b tr chng, khng c d kin trcn mt bng chung.

- Mi ng ng mm hoc cng t trn mt t phi c bo v trnh h hng do xc c qua li tt hn ht l t di rnh do.

Lp t ng nc (hnh 3.4).

Vic lp t ng nc bt u t ng h t trong cng trng v thng thng gm c hai nhnh:

ng thp 26 X 24

T ci 26 X 34

Van 26 X 34-L ng 26 X 34 c=z = 3

T ci 26x34

~ Thu nh 26 X 34 - 20x27

Van ng 20 X 27

ng cht do (PVC) 20 X 27

Hnh 3.4: Chi tit lp ng nc trn cn trng

47

- Mt cung cp cho cc khu sinh hot, lm vic cho nhn vin vo cc chu ra, nh v sinh, nh n, cc bung lm, cc ni ra chn tay... ng ng ny c th chy dc theo hng ro ca cng trng nu nh cc ln tri u t bn cc ng vo.

- ng th hai dng cho cc trm trn btng, trn va xy dng v:

- Bi sn xut btng bn thnh phm hoc nhng ni lm vic cn cp nc.- Cc ni ly nc ung trn cng trng;- Cp nc cho cc nh ca cng trng.

Lp ng in (hnh 3.5 v bng km 3.3).

To nh xy

/ . / N / V .

Hnh 3.5: Lp i in trn mt bn cm trn

48

Bn^ 3.3. Thuyt minh km theo bnh hnh 3.5

Cc k hiu Cc mch v cc thit b

TI

ng dy in nhnh th nht ng dy in nhnh th hai ng dy in nhnh th baCt in ca nhnh 2 v nhnh 1 (d kin 14 ct, chiu cao 8,5m) Ct in ca nhnh 3 (cao lOm)Nc - cc nhnh hin c:

Phn phi in trn ct

My ct in tng lOOkVAT2 Ngun vo:

T3

1 my nn lu ng n di ng 24V Thp sng cho 2 ln Ngun vo:

T4

1 cn cu 8061 trm hn hoc my nn kh lu ng. Thp sng 220V (n di)Thp sng 24V (n di ng)1 ca a Ngun vo:

T5

1 my ct

1 my un1 my nn kh lu dng1 ngun chiu sng 220V1 l hm nng thc n (cho 50 ngi)

T6Thp sng 210V 1 trm hn

T7

1 ca a Thp sng 220V 1 my trn btng2 sil 25T vi 2 vt v tn 1 my cp nh1 ngun cho trm hn hoc my nn kh lu ng Thp sng 220V

49

Ui

Ti cc my trn b tng hoc cc thit b c nh

R le visxi nhy trung binh

n ni dng

--------------CH THCH-----------

B tr my ct visxi nhy trung binh khng chm tr ni vo t phn phiB1, B2. B3 l t phn phidc bo v bng my ct visxi nhy cao (30ma) khng chm tr

EZZ ng lun cp

Mch tip t

ng dy trn ct

Cn ngt din pha ngoi

Khu A

Khu B

Thit b nh v tri s c

Tip t trm

Phng t bin th

B hn ch qu p

Kim tra cch in c tn hiu

Hnh 3.6: S ( p dt in trn CIH trng

Ngy nay, trn cng trng xy dng no cng s dng cc my mc v thit b c ng c in, ngoi ra cn phi bo m nh sng cho cc khu nh v ni lm vic. Do vy u cn thit phi b tr cc trm din tm thi ph hp vi cc quy nh v nh mc hin hnh. Trm in ny c th xut pht t kh vc cng cng - u t ng in ngoi cng trng vi mt my bin th trung th/h th, nu nh mt cng trng ln th c th t mt hoc nhiu t my in cho tng cm thi cng. Trm ny c th giao cho mt cng nhn lnh ngh ph trch. N bao gm mi thit b v cc mch cng sut khc nhau tu theo d thp sng hoc cung cp cho cc u my ln (cn trc, trm trn btng) hoc dng c cm tay (m rung, my mi, my khoan v.v...). Trm c mt t phn phi (cch in vi ca c kha) gm ns h o in, my ngt tng v tay iu khin ngoi, cc cm ( cung cp cho cc hp sch tay hoc c nh trn cng trng) vi dy trung ho + dy t v bo v bi cu ch c kh nng ct in cao i vi mi cm.

Thit b an ton c th l mt my ct c rle vi sai nhy trung bnh trn cu dao tng, hoc mt my ct c trang b tn hiu sng v ting ku. Xut pht t t phn phi ny, cc cp ngm hoc trn khng cung cp in cho u my, khu lm vic, sinh hot s dn n cc hp ring bit phn phi li cho trm btng, cho cn trc nu nh cng trng c nhiu hng mc v cho cc dng c khc. Mi hp nh vy c bo v bi mt my ngt vi sai v bao gm cc cm khc nhau, trong c ngun 24 vn cung cp cho cc n lu ng cong trng v dng c cm tay.

Cng c cc trm lu ng cung cp tm thi cho cc cng trnh, vi my bin p c nhiu in p.

Chng ta hy xem v d v s lp rp in mt cng trng xy dng c n gin ho d hiu (hnh 3.6).

Cc u ni khc cn thc hin:

- in thoi l mt trang b Gn thit- cho php lin lac nhanh vi tru s, cc nh cung ng, ch cng trnh v cc c quan y t v an ton, cng an...

Vic u ni ny do nhn vin bu chnh vin thng thc hin qua ng dy trn khng nu nh cc phng lm vic u gn vi ng cng cng, cng c th qua cp ngm. Nu cp in v in thoi t trong cng mt rnh th chng phi cch nhau ti thiu 30cm.

- Kh nn c th c cung cp di mt p sut t 3 n 7 bars qua mt my phn phi chung. ng ng cng trng dng ng mm vi cc van kh nn thch hp ni c vi cc my c dng kh nn.

- Lm cc nhnh tiu nc sinh hot. l vic u ni ng ng n ca tiu nc cng cng.

- Cc van nc cc khu v sinh, bng cc ng ng () 100 n 120mm.

- Nc dng i t chu ra v mi im dng nc khc hoc t ni ra my xy dng thot bng cc ng xi mng li tm lOOmm l thch hp.

51

C hng 4

B T R C C T H I T B C H N H

l cc thit b nhm vn chuyn cc vt t mt im ny sang im khc ca cng trng (vn chuyn cc vt liu, cc bn thnh phm, cc vt t v dng c c bit lm vic v.v...), gi v treo trn mt t nh mt h thng nng.

Cc im xut pht v n c th c t trn cng mt mt phng ngang hoc cc mt phng c cao khc nhau.

Thit b ny cho php c gii ho cc thao tc nng, lm gim bt s mt nhc ca cng nhn, do tng c nng sut lao ng trn cong trng.

Do s tin b v k thut thi cng hng ti ch to sn cc sn phm tng i nng v s dng vt liu t bit v cp pha, ngy nay thit b nng tr nn l yu t ch cht tng nng sut, l cng c s mt ca cng trng. Ngi ta suy ngh cc plurne php thi cng, tu theo thit b ny, phng php thi cng v cc thit b nng lun lin h mt thit vi nhau, nu ngi ta mun iu hnh mt cng trng hot ng tt.

C rt nhiu kiu thit b nng c c gii ho ph hp vi bn cht v quy m tng cng vic. Chng ta khng cp n tng loi trong khun kh cun sch ny. y ta ch ch trng gii thiu vic lp t cn trc quay kiu thp, v n t hp c hai thao tc vn chuyn ngang v ng kt hp qut mt khu vc rng hng chc mt bn knh v chnh v vy n c dng rng ri nht trn cc cng trng.

- Trang b mt cn trc nng cho cng trng cn phi c:

Mt din tch mt bng cng cao trnh, rng hp tu theo chn ca cn trc, di ca ng cn trc chy. Khi lm vic c nh th din tch trn c th gim bt.

Mt t phn b cc ti trng v chu c sc ca ng chy: cc dm btng trn bn tip xc, kt cu y, cc dm dc trn dm ngang v khi dn. khi btng.

Mt ng chy bao gm cc ng ray thch hp c cc thit b chn dng hoc c mt thit b neo nu nh cn trc t c nh.

u my (hnh 4.1) n gm mt khung (c hoc khng c gi chuyn hng) c cc ng c v lp ln mt ct hoc thp (ct hnh vung vi cc ti gm mt s b phn) v mt cn ca trc vi mt xe ra di ng, cn ny c thng bng bi mt i trng: i trng c treo mt vt dn cui cn. pha trong ct khung c mt thang

4.1. THIT B NNG CU

52

ln ca bin iu khin. Ca bin ny b tr di trc quay ca cn hoc trn trc quay.Nhng cn trc nng trn 30T/m v trn 25m cao di mc, ca bin thng quay c.

Trang b mt ng c in iu khin vi mi chuyn ng ca cn trc: di chuyn trn ng, nh hng cn cu, nng vt nng v cui cng lm cho xe ra di chuyn dc theo cn, cng khng th qun cc thit b an ton c bn nh cc thit b gii hn hnh trnh ca cn trc, gii hn trng ti, ngu lc, phi c my ngt vi sai, b phn tip t.

Cc ph tng khc nhm nng cc ti trng (khay, dy mc, thng ben...), thit b no cn trc v cc thit b khc nh my o gi o tc gi, cc n chiu lm vic ban m, cc n bo hiu khi ang hot nc.1 c . c

- B tr mt cn trc di ng trn ng ray.

Tm tt mt s yu t chnh chon:

- Tnh cht v khi lng cc cng vic.

- Cc bin php thi cng xc nh trc.

- Cc phng tin thi cng ca x nghip hin c v kh nng u t.

- Cc iu kin ca a im xy dng (cng trng cht hp chng hn), sc chu lc ca nn, s hin din cua cc to nh cao hoc c cc ng dy in gn cng trng.

Quy trnh lp t: y l nhng bc lin tip trong vic lp t cn trc:

- B' tr ni lp t theo mt bng h tr chung v chun b khu t lm b.

- Thi cng t, t ng chy v ng thi chun b b phn dn, t cp cp in v cp tip t.

- Lp rp cn trc.

- Kim tra mi vn d ve ki thut v an ton de xin php dc vn hnh cn trc.

B tr v chun b mng t cho cn trc:

Mt bng b tr chung cho ta v tr lp cn trc v ng chy tng ng vi to nh nh xy (hnh 4.2), nhng v tr ny khng phi lun lun c nh m ch sau khi san lp mt bng mi c quyt nh cui cng. Vic chun b nn mng cho cn trc c thc hin ng thi vi cc mng o khc. Ch huy cng trng phi t trc cc ranh gii v cao trnh v mc ca cc v tr la chn mt cch chnh xc trc khi khu t b "o ln" khi o mng. Tt nhin, v vic ny cn b k thut thc hin mt bng chung phi lm tt to thun li cho chi huy cng trng gn kt sn lp t vi mt dng mc chun khc l mt tin ca khu nh nh thi cng.

Xc nh v tr c b tr cn trc l mi u ca khu t vch mt hoc hai mc cho php lm r hai trc song song ca ng cn trc chy v ng gia hai trc con ln tng ng trn mt bng chung. Mt nn chun b phi c chiu rng ln hn 75 n 8(Jcm v pha mi bn trc.

53

- Xem xt k cc mt bng kin trc, cc mt bn nht l cc mt c xut hin nhng phn nh ra ca cc mt tin nh ban cng, mi che.

- Xem xt ti cc mt h mng o nu nh cn trc t bn b' h mng: nn xa inh mi h mng trnh b lt nho (hnh 4.2) hoc tin hnh gia c thch hp mi h mng.

- Quan st cc lp t l ra do san nn v lm r sc chu nn ca nn v c tnh ca cc loi t ny. Nn trnh khu t p v t st.

- Ngh n vic gii to mt khong khng gian cn thit cho vic tho lp cu.

Vic chun b khu t lm cn trc l mt lm t cho n phi lc chu nn. Thng thng khi la chn cn trc, phng k thut quan tm n lc chu ca nn, xem xt n bin php an ton, kinh t nht ci thin t nn lm cho s phn b ti trng trn nn hp l nht.

Trc khi tin hnh nh v phi:

Trc quay

ct treo cn Dy ko cng Cn trc__A _

X Chn n hi

Khung lng

Chn g.

tTTTTTTTTTT/7Thanh ngang b ..a a Khi d.

Hnh 4.1: S cl cn trc thp v hi ch cc b phn

54

H nh 4.2: inh v lp t cun trc

Mi con ln truyn ln t nn khi cn v tr thng gc vi trc dc ca ng chy l ti trng bao gm gia 2/3 v 1/2 ti trng tng cng (cn trc + vt dn). Chng hn, i vi mt cn trc nng tng cng 48 tn, t nn c th chu ng mi bnh, trng ti l 32 tn. Nu nh ng sut chu la 3kG/cm2 th mt cn thit chu lc phi l: 32.000:3 bng 10700cm 2 tng ng vi hnh ch nht c cc cnh 120 X 90cm .

Sau khi tnh ton nh vy, ta c th quyt nh c phng thc thc hin t ca ng chy cn trc. Cho d vic Ihc hin nh th no, nhimg trc ht khu vc cn phi c:

- Bc ht lp t trng trt.

- San bng tuyt i mt nn.

- Tiu nc nn nhm trnh thm thu nc di ng chy lm gim sc khng ca nn v s gy ln st;

- Ci to hon ton vng t xu (v du n h t p) bng bin php a vo vt liu th cng hnh thnh tng lp; m nn nn tht cht.

55

ng cn trc chy

Nn ng chy s cu to khc nhau tu thuc vo tr s ti trng tc dng ln ng ray, trng lng truyn qua mt trong cc con ln c th t ti 2/3 tng trng lng ca cn trc khi di chuyn. Nh vy i vi t nn tt c th lm vic ti 3bars s ngh:

- Cc ng ray t trn cc dm ngang v dm m cht i vi cn trc t 3 n 15 tn/m.

- Cc ng ray t trn dm dc bng g ln cc dm ngang v t trn lp dm i vi cc cn trc t 16 n 30 tn/m.

- Cc ng ray t trn cc dm dc btng ct tlip, i vi cc cn cu trn 30tn/m. Trng hp ny thng gp trn cc cng trng xy dng hin nay.

trnh ng ray lm vic b un, ta nn gia c trn mt dm dc (g, kim loi hoc btng ct thp) trn ton b chiu di ca n. Ngoi ra, dm dc cn tng thm n nh ngang ca ng chy v m bo phn b ti trng tt hn.

Cc cng vic c tin hnh trc khi lp rp cn trc.

Chun b trng ti dn (hnh 4.3).

Trc ht m bo n nh ca khi lng ti dn phi bo m gim c trng tm ca u my. Tng trng lng ca khi dn thay i theo chiu cao ca cn trc v cu to ca n (trng lng, th tch v v tr), phi tun theo cc ch dn mt cch cht ch ca ngi ch huy thi cng: c th cho php trng lng thay i trong phm vi 5%. Ch huy trng cng trng phi quan tm n sc nng ca khi dn v phi xc nh r trng lng ny bng cc bin php tin cy. Khi khi gm cc thi bng btng ct thp th trng lng ring ca thi btng phi t ti 1,9 n 2,4 tu theo phng thc ghp cht cc thi li. Cng vy, nu ne cc khi ng ray lm ti trng dn th khi lng dn phi c kim tra v phi xem mi khi c trng lng thc l bao nhiu.

Kch thc chung ca khi dn tc l th tch m n chim v b' tr n c mt tm quan trng c bit: trng tm chuyn dch c th gy nguy him cho s n nh ca cn trc. V u my thng rung, cho nn cn thn trng gi cho khi dn ny v tr c nh trong khun kh mt ci bng g c cc ai st ging chc. Trn hnh 4.3 cho ta mt v d v khi dn ca mt cn trc 15 tn/m.

Khi dn ca cn i trng cng phi c thc thi theo quy nh ca nh sn xut cn trc v thng thng dng cc khi btng ct thp.

- Chun b, th it b no hoc buc cn trc

Cng vic ny tin hnh nhm mc ch cho cn trc chng c sc gi vt qu mt vn tc nht nh v cng s dng c nh cn trc mt cao m cn trc c th lm vic t do.

56

A. Cc thanh dn bng b tng ct thp A,. Cc thanh thng

B. Bng thay i ti trng dn

Chiu cao Vt dn S lng khi dn

21m 14t26 khi 1,50m

144 khi 1,90m

24m 16126 khi 1,50m

166 khi 1,90m

27m 18t26 khi 1,50m

190 khi 1.90m

30m 20t26 khi 1,50m

214 khi 1,90m

c. Khi dn hon thanh

- a dng in n chn cn trc v thc hin n i t.

Vn u ni in c xem xt chng 3. Cn u ni thit b in ca cn trc l cng vic chuyn ngnh, y chi a ra mt s nhim v m cn b k thut ph trch thi cng phi bit.

- Mi cn trc c cng sut s dng in tnh theo kVA (kilvn ampe). Nhimg vicin cho cn trc c lin quan n li in chung ca cng trng v cn cc ng cin khc cng lm vic ng thi. Nh vy, phi bo m rng in p cn thit t cp in cho cn trc s phi , v khi in p khng s lm ng c in nng v c nguy c chy.

- C thit b ngt t gn ng chy, ngt in cho cn trc trong trng hp xy ra s c k thut hoc con ngi. Ta c th d dng vi ti thit b ngt m khng bt buc phi tro ln b cn trc.

- Cc dy cp in (dy mm) phi c bo v khi h hng v khng c ko l trn mt t.Trng hp ny nn c mt cun qun dy cp v c mt b phn cp cun nh trn hnh 4.4.

ng cun v mng bng g

H n h 4.4: Cun cp c h phn d dy

tdn

Cp mm cp in (N+1) dy N= s dy cn thit

Dy ni t

Ni d(T x in .___a _____

INi __p in - t i t r y j QNi t

u

2Dy ni t 28m/m tit lin bng ng hoc 50m/m st hn

Ni dt

cng tc Cun cp cung cp Phch cm

Phch cm hoc cu dao ni t

Hp kim loiCng tit din dy dn

Hnh 4.5: S d tip t c ho cn trc

58

- Ni t cho cn trc: nh hnh 4-5 cho ta s tip t cn trc. K h u n g k im loi ca can trc v cc ng ray phi c cc ng tip t tng ng v ton b cn c ni vi thit b ngt vi sai hoc vo h thng ngt t ng trong trng hp cn dng in d.

Ni t ca ng chy l cn thit cho mi mi ni ng ray.Ta ni mch "su" cc ng ray i u nhau bng mt thanh ng hn vo li ca ray (hnh 4.6).

- Gii to khng gian cn thit cho cng tc lp rp.

Lp rp cn trc, l cng vic ca chuyn ngnh my xy dng v cn phi s dng mt kp th lnh ngh. Trong khi lp rp, bt buc ngi li cn trc v cng nhn c kh bo dng phi tham gia. V c nh vy mi c th nm c cc c tnh k thut ca n thng qua vic ging gii trong qu trnh lp cn trc ca cng nhn lp rp.

Bc cui cng ca vic lp t

- Khi lp xong, cn b k thut lp rp phi vn hnh th, t cn trc trng thilm vic, thc hin cc u ni din cn thit, bi trn cc b phn chuyn ng, cc bnh rng, bo m cho cc thit b an ton thao tc clns: qu ti, ngu lc, hnh trnh ca xe ra, hnh trnh di chuyn v nng. Mt khc, trc khi a cn trc vo lm vic, cn phi c cn b xc minh li thit b n} mi cch k lng v cc mt. Cc thit b gii hn an ton tiu lin quan lin mi dng tc ca cn rc v dc iu khin bng c hoc bng in. Cc h phn ny nt nhy cm i hi phi c mt s kim trathng xuyn ca mt cn b lnh ngh trn cng trng: bn thn ngi li cn trckhi c s o to chuycn hoc mt cng nhn c kh, in ca x nghip. V mt s cn trc c trang b phanh in l a vo ng c ca ti nh hng, nhng phanh ny vi thi gian s dn dn mt chnh xc khng nh hoc khng xit c, n b rung. Ngi iu khin cn trc phi lu pht hin v thng bo ngay.

- Ngoi ra cn lp t mt h thng si trong ca bin li v trang hi mt bnh phng ho.

- Bo v cho ngi li cu khi nguy c in git: t trn ng cp in ca cn cu mt cu dao vi sai c nhy cao (30mA).

- Bn thn cn trc nn c bin thng bo nhng iu cn thit cho php lm vic ' cn trc, cc lnh s dng v nht l cc k hiu v cc c chi iu khin trong ca bin cn trc.

Cp c khuyn bt bu lng

Dy ng bn hn (S > 28mm2)

Kiu st trn hn in () > 50mm2

Hnh 4.6: Ni "su" cc n ray

59

- Cc bin bo an ton: "Cm ng di ti trng", "cm lm tc ng chy", "nguy him khi qua li trn cc ng chy"

- C mt pan ghi cc trng ti gii hn theo tm vi, thng thng thm vo cc tm bin nh ghi chiu di cn c tnh chnh xc hn cc khong cch.

Cabin ca cc cn trc hin i thng gn cc tm ch: trng ti, mmen lt, tm vi, khong cch ca mc cu so vi cn.

- Cc k hiu u tin trong trng hp khu vc lm vic ca cn cu b ct gim: gn vo trong cabin ca mi ngi li.

4.2. THIT B SN XUT BTNG

sn xut v phn phi btng l loi vt liu ti cn thit cho cc cng tnrng. l mt ni cung cp vt liu ch cht v gi tr ca cng trnh thng chim n 50% l cng tc btng.

Ngoi ra, n l mt trong nhng trm em li nng sut cao cho cng trng do kh nng c gii ho, t ng ho cao ca trm trn, do vy khi sn xut ra lm 3 btng s c gi thnh hp l.

La chn v tr lp t trm trn btng cn phi lu n:

- Vt t lin quan n hn hp btng, my trn, thng trn.

- Mt h thng cung cp btng p mg nhp sn xut ca cng trng, h thng bao gm: my trn v cc b phn d tr vt liu (cc cp phi; cht dnh kt), b phn ong m, b phn vo my trn (hnh 4.7).

- Cc thng btng, phn phi btng n cc im s dng khng c lm chm tin sn xut.

- Cc thit b lp t cho trm trn phi tp kt chn cng trnh.

- Thng thng cn mt ngun in nng cc thit b lm vic v c ngun nc sch trn btng.

Vic lp t my trn:

- Cc cng tc chun b, cho d la chn loi my no cng cn phi: c c mt phng thc s cng mt cao trnh. Sau khi san gt ht t trng trt, ta phi thi cng mt lp btng cao hn mt t khong 15 4- 20cm v gii hn lp btng trong phm vi my trn, san mt hi dc mt cht ra ngoi trnh nc ma cng nh nc ra my trn ng li chung quanh trm trn. C ng ra vo thun tin. Ngoi ra nn lm mt rnh c np y (20 X lOcm) m bo dng nc dng c thot v nn c mt h cha cht cn nu nh dng nc c cha cc cht dnh kt phi cho ra ng thot nc chung (hnh 4.8).

60

Hnh 4.7: S l ' thn trm trn b

tiu

Hnh 4.8: Cc hli nc ra trm trn btn

Rnh b tng dn t tram trn

- Lp t theo cch c truyn: i vi cc cng trng m cng tc btng hoc thi hn thi cng khng ln, ng thi gim cc chi ph lp t trm btng, khi ta c th dng cc cch lp t sau:

My trn btng t trn mt t hoc cao hn mt cht trn cc gi . Khi my trn c trang b mt thng cha lt, th nn h n trong mt h c kch thc hp l, y v thnh s thch hp cho vic trn, nhm d dng cho vic cung cp btng thng lt. Nu nh khng th o c h (chng hn my trn t trn mt tm an c sn) hoc khng mun lm theo kiu th c th thc hin bng mt mt dc tht chun lm ng vo cho cc xe ct kt.

- Lp t theo cch hin i: C ba cch lp t tu thuc vo v tr v khi n im chung v ton b trm trn btng:

- My trn c th t cao hn so vi mt nn t nhin, dng bc sn bng khung g, hoc bng btng ct thp, vi cc thnh thp bng btng loi bng cc khi xi mng, bng cc ng lng lm chn . Cch trn c nhiu u im v c th lm v sinh d dng chu vi v my trn, nh v cao va s cho php x btng khi thng trn tin li hn.

- My trn t di mt h o c mi to thnh mt phu rt btng v c chia thnh ngn. Nh vy, ta li dng trng lc cung cp cho my trn cc cp phi ht. Cc vt liu cp phi ny trn mt t t nhin s thun li cho vic cung ng bng t v ng thi li tit kim c khong khng gian b chim v gim nhn cng phi leo hng ngy nhiu ln ln ng vt liu.

- Trm trn btng di chuyn c (hnh 4.9).

Hnh 4.9: Trm trn btng hi ng

62

l gii php l tng mt khi cc tiu ch chung ca cng trng cho php la chn kiu ny. Nh vy, cc cng vic chun b a trm trn vo v tr l cc k n gin (ch l khu t my trn v khu cp phi) v khi kt thc cng trng, trm trn chuyn i s tn ph rt t cng.

Thng thng trm trn loi ny mi thnh phn nh thng trn, xi l, thng lt, tu diu khin v.v... trn mt r moc sau t ti v c th di chuyn mt cch d dng. Hin nay, mt s trm lu ng t ng ho hon ton theo chng trnh v m bo mt nng sut t 50 n lOOm /gi. Tt nhin, cc trm ny ch ph hp vi cc cng trnh xy dng dn dng ln.

1. Bi t r vt liu cung cp ch my trn

Tu theo vic thit k chung ca trm m cc thit b ny s rt n gin hoc i hi phi c nhng thit b phc tp.

Thit b tr vt liu si, ct

Cc nguyn tc v t chc i vi vic b tr thit b ny cn c tn trng. Cc nguyn tc ny nhm gim n mc ti thiu mt bng b chim, vn chuyn, bc d cc sn phm nng. Nn tun theo cc nguyn tc sau:

- Bi tr ng thi gn trm trn v gn cc dng ra vo trnh thao tc khng thun ca xe ti trong cng trng, nh vy nn nh hng kho bi hoc cc phu thu cho ph hp vi vic sn xut btng, ng thi cn xt ti chiu lu thng trn ng quanh cng trng.

- Li dng trng lc mt cch ti a:

- Dng cc phu hng o trong t vi cc thnh phu dc ti 50 trn cho vt liu t ri.

- Dng h thng bng ti khi cc phu phi b' tr trn cao.- Bi tp kt dc chia thnh ngn sau mt bc tng, c trang b mt xng ko nhm

gi dc vic lu tr tt, tc l cc ht ct si c th chy t do ti cc ca sp khi c mi dc t nhin thch hp cho ht vt liu chy xung.

- Chia ngn khu cha bng cc vch ngn (heo hnh sao, nhm m bo cp phi ht theo thit k.

Ph hp vi cng sut cha c xt ti v tr cn thit, ti s lng cn cho mt ln bitng cao nht. iu s quyt nh quy m khu cha hoc dung tch cc phu.

Thit b tr cht dnh kt

- Phi d kin c mc an ton cung cp vt liu dnh kt di bt c hnh thc ciung ng no theo lnh ca chi huy cng trng.

- vt liu dnh kt ni trnh c thi tit bt thng, trnh ni c m cao.

- Cha vo cc ngn ring tng loi cht dnh kt khc nhau.

63

- Khng c lu tr lu cc loi xi mng ng cng nhanh; ch cung ng va lng cn thit.

Gii php c truyn dng kho cha ximng bao, xp thnh hng, t p dng cng trng ln. Trn nhng cng trng ln ngi ta thay th bng cc xil cha ximng ri. Gii php ny t ra kinh t mi phng din: mua, vn chuyn, chim ch do lu tr, gim c cc dng tn tht, sc lao ng cho cng nhn. Tuy nhin, khi phng thc ny c chp nhn, cng nn mt t ximng bao d tr t 5 n 10 tn s dng khi cn thit vi khi lng t.

- Kho tr ximng (xem hnh 4.10) c th dng cc tm lp ghp tho ri c bng g hoc kim loi, nhng phi c sn cao hon mt t, thng gi hp l, v nu c th lm hai ca ra vo. Chiu cao cha khng vt qu 1,50m, hng trn cng va tm cnh tay vi ca ngi vc. Nh vy cho php xc nh c din tch cn thit theo s tn d tr, nn tnh ton khong l,70m 2 din tch t (k c hnh lang i li) cho 1 tn ximng. V tr kho ny so vi ni t my trn c mt tm quan trng khng th b qua, v s khun vc cc bao ximng l nng n i vi cng nhn, nn t cng gn cng tt, hoc d kin trc mi ln btng nn cha tm thi trn sn vn ghp v c vi bt che ma.

- Xil cha xi mng (v d trn hnh 4.11) l mt phng thc hin i c xu th ph cp Xil cha xi mng ch l mt thng hnh tr c th cha c t 15 n 250 tn ximng: cc trng ti c nh hnh. i vi cc cng trng c khi lng btng hng ngy ln th c th d kin 2 xil m khng cn phi ong m ximng khi trn hn hp btng.

Trong nhiu trm btng, xil c d kin t ngay pha trn thng trn, s gim c s cng knh ca trm.

B. Ln 2 ca cho cng trng va A. Ln 1 ca cng trng nh (n^ ,n rng)

Sn vn ghp cch li nen

Hnh 4.10: Kho tr xi m m> tm thi

64

con ni u

Q.ro

4.11: Xl cha ximng

2631

6

- Thit b o dung tch: l cc thng c chia ngn vi sc cha thay i c nh cc l kp gn bn l v c th thay i c nghing cc ngn to ra nhng dung tch nht nh (hnh 4.12).

Thit b nh lng cc thnh phn ca btng

Hnh 12: Th n o dunq tch c 3 Hn c th iu chnh dc 25 lt mt

- Cc thit b o trng lng: c nhiu kiu o cho cc cht dnh kt v ht cp phi. Thng thng l dng cn c con trt o lng ximng hoc dng cn c bn c.

66

^ u o

H n h 4.14: o trn V ln cc vt liu ht (si, ct)

Cn bi lp trn 4 li dao, u o khc 10 kg mt, c trn 2 mt

Cc thit b cung cp vt liu cho thng trn.

a ct si v ximng vo cc thng trn thng trang b cc thng lt, nghin cu hnh dng c bit m bo x ht v nhanh cc vt liu trong thng.

Khi my trn t cao, cn thit phi ko di cc thanh trt ca thng lt, thay i dy cp thao tc v hnh thnh mt h thch hp cho loai thnq ben ny. Cng c mt s trm c xem xt trc cch a trc tip ximng vo thng, y l mt u im.

- a nc vo nh mt thng trung gian gn vo my trn. Cn lp km theo m t ng h o th tch nc.

2. Thit b in

Vn ny khng cp n i vi mt s cng trng nh, v vy mc in qu t khi thc hin khi lng btng t. Cho nn cc cng trng nh thng trang b cc my trn dng ng c xng hoc du chy my. V vy thit b in ch t ra khi cc cng trng thc hin mt khi lng btng ln vi thi gian di.

Vic lp t thit b khi bao gm nhiu ng c: lm quay thng, nng v hm thng, ng c my gt san, hoc ng c cho gu dy cp cc vt liu, ng c ca vt ti ximng v trong mt s trng hp cho my nn kh. Mi u ni vo thit b phi bt u t mt t phn phi in bao gm thit b an ton c tn hiu, cn phi ni t cc v kim loi ca my trn v xil.

3. Thit b tho x v phn phi btng ti

Mi cch tho x btng i hi mt cch b tr ring:

67

- i vi xe ci tin (hin nay vn cn s dng mt s trng hp) hoc t t , cn thit phi chun b ng cho xe i b tng nu nh mun tit kim thi gian, trnh ri vi va btng, gim sc lao ng cho cng nhn btng. Cng c th dng bng chuyn ti, hoc mt cn trc cp, hoc cc ng dn cho vic bm va btng.

Cng c th dng xe t c thng quay ch btng t ni sn xut btns thng phm n ni . Cch ny thng dng cho khi lng btng ln, t thng quay c dung tch kh ln (5 4- 10m3) nn i hi c mt h thng tip nhn hon chinh v ng b trnh lng ph cng sut ca trm trn. Cng c th sn xut btng nh my cung cp lin tc cho nhiu cng trng xy dng. Nh vy mi cne trng i hi c trm cha btng ti t hoc cc xe t c trang b thng ben di ng v kt hp vi cn trc chuyn btng ti n ni .

Cng c mt s ni cn dng xe gong ch btng n cng trnh xy dng.

Ngoi cc thit b nu trn, ngi ta cn lp t mt trm kh nn dng vo vic m btng. Mt s thit b cm tay m nn btng cng c trang b cho cng tc btng.

4.3. B TR TRM SN XUT CT THP

1. M c ch

Cng trng bao gi cng c mt trm gia cng ct thp phc v cho cng tc btng ct thp v gia cng cc chi tit c kh nh.

Tuy vy, a s cc cng trng loi nh v trung bnh, thng t quan tm n vic b tr trm sn xut ct thp v theo truyn thng h mun cc th ct thp t xoay x v un ct thp bng th cng, nhng vn m bo cht lng. Nhng cng phi lu rng, nng sut ca trm sn xut ct thp c th gp hai ba ln mt khi c gii php cng ngh hp l v c c gii ho cao.

Trm sn xut ct thp cng trng theo li truyn thng c c im tn mn, lng ph vt t, nng sut khng cao v nhng ch cho nhng x nghip chp nhn gii php trang b mt trm ct thp c my mc hin i, tp trung sn xut ct thp cho nhiu cng trng thi cng ca doanh nghip. iu ny cho php to ra nhng thun li sau:

- Khu hao nhanh cc thit b t tin, do lm vic lin tc v hiu qu. Vi mt trm sn xut ct thp c nh, xng y th trnh c nh hng ca thi tit, b tr c nh mt ni s c iu kin c gii ho sn xut v vn chuyn, lm tng hiu qu kinh t.

D dng chuyn mn ho, t ng ho, lm vic trong iu kin n nh, nng sut lao ng cao, tit kim c chi ph lao ng cho x nghip.

68

- S tp trung ho ny cho php c mt t chc lm vic tt hn mi cng onkim tra c cht lng gia cng ct thp ci thin c cc iu kin v sinh van ton.

- Gim c cc mt mt hao ph vt t, vt liu khi gia cng, c th tit kim c 2 H- 3% lng ct thp.

2. S b tr chung trm sn xut ct thp

Cho d gii php no c chp nhn, kiu c truyn gia cng bng sc ngi hay hin i vi thit b tn tin cng nn quan t m n cc vn sau:

B tr mt kho cha ct thp cc loi cho tng cng trng.

B tr mt my ct ct thp vi bn ct c thc o di.

Cc bn gia cng c trang b cc kliuu un bng tay hoc cc my un hnh cung a nng c th lm c nhiu dng ct thp.

Mt bi lp rp ct thp ghp cc b phn gia cng trn cc m hoc gi .

Mt khu vc cha cc khung ct thp gia cng, ch t vo v tr thi cng cn cu nng v vn chuyn ct thp trong trm v khung ct thp gia cng xong n bi cha.

Ngoi ra, cn tu theo s suy ngh sng to ca ngi ph trch c th cn thm nhng trang b ci thin iu kin v sinh, an ton v mi trng ni sn xut ct thp.

Cc tiu ch c bn tnh cng sut trm sn xut ct thp.

i vi mi trm sn xut ct thp u c cc tiu ch sau:

- Tnh cht v khi lng btng ct thp m t tnh ra s lng ct thp cn thit theo tn: c cng trnh cn 15kg ct thp trong lm 3 btng v cng c cng trnh ti 150kg/m3 hoc ln hn nni. Bn (l ton khi ng btng ct thp s cho ta bit tiu ch ny.

- Thi hn thi cng v c bit l thi gian thi cng cc cng trnh btng ct thp. Cc thi k ny s cung cp cho ta qua bn k hoch thi cng phn th, xut pht t hai tiu ch trn, ta c th xc nh nhp sn xut v tr li cu hi cn bao nhiu tn ct thp lm trong 10 ngy hoc sut thng. T suy ra din tch kho v thi hn cung ng ct thp d kin c nhn lc v bc th cn thit.

- V tr trn cng trng: trm sn xut ct thp i hi khong khng gian ln, ti thiu 300m 2 cho mt cng trng loi trung bnh.

Tiu ch ny cn quan tm hn hai tiu ch trn, v phi ra quyt nh cui cng hng vo gii php vo sau y:

- i vi cc x nghip thi cng nhng cng trng nh khc nhau, cng tc n chim a s, s lng ct thp l qu t, th khng cp n trm gia cng ct thp, m theo phng php truyn thng.

69

- i vi cc x nghip phi gia cng ct thp khong 20 n 30 tn mt thng [h phi chp nhn:

- V tr cn thit ca trm ct thp l > 300m2 v c b tr theo s ca tng mt bng cng trng. Tu theo kh nng ti chnh ca doanh nghip m mua sm trang thit b.

- Nu khng din tch b tr, c th chia nh trm thnh 2 ni kt hp sn xut ct thp:

- Hoc thc hin gia cng ct thp thng qua mt c s khc cung cp v lp t ct thp vo cp pha btng.

Nh vy cng trng khng phi quan tm n cng tc ct thp.

- Hoc c s gia cng ct thp ny ch cung cp tng b phn ct thp ph hp \i tin thi cng vic lp rp v t ct thp ti ch do cng trng thc hin.

Nhng cng trng nh, khng nn tch b phn gia cng ct thp cho x nghip khc thc hin. Khi c th to ra cc b phn lu ng t phn cng trnh lp rp gia cng ct thp ti ch theo phng php truyn thng. Gii php ny cng t ra c u im l trnh c phi lu gi ct thp thnh phm v gim c khi lng vn chuyn.

i vi cc cng trng c khi lng btng ct thp ln, cn ngh ti gii php cng nghip ho cng tc btng ct thp n mc ti a hoc p dng phng php lp ghp, sn xut cu kin trong nh my.

3. B tr trm sn xut ct thp

La chn vi tr trm sn xut ct thp nn cn c vo kh nng sau:

- ra mt con ng hoc song song vi trc chnh vo cng trng. B tr nh vy s gim nh cho vic cung ng v bc xp ct thp, t chuyn ch s khng phi vo cng trng.

- Trong vng lm vic ca cn trc. Tt nhin, tr khi trm tp trung cc ct thp thnh phm hoc a hnh khng cho php c kh nng b tr khc.

V tr tng i gia cc b phn khc nhau trong sn xut ct thp. l s b tr ni b trm sn xut v vn ny ch lin quan n vic t chc lm vic (xem chng 6).

Hng ca kho cha ct thp quyt nh vic b tr cc b phn khc, nu nh ta mun p dng nguyn tc ct thp phi c vn chuyn theo cng mt hng hoc song song vi nhau, cho d gia cng hay cha gia cng. l gii php l tng trong b tr tuyn tnh, nhng trn thc t t khi thc hin c. Cc cch b tr tng b phn ca trm ct thp c th tham kho hnh 4.15.

ng vn chuyn ni b ca cc b phn cn tun theo: cc v tr dch chuyn ca cng nhn, vn chuyn st thp khng c giao nhau, phi l ng ngn nht. Nh vy, khng gian ca cc b phn sn xut phi v khng chng cho.

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Ni cha cc ct thp gia cng ra pha trong khu vc lm vic, ca cn trc, nhm gim vn chuyn bng th cng.

a) B tri thng hng

5 0 * 60m

12 + 15m 1 6 - 8m 1 6 -- 12m 1 6 H- 12m 1 $ -r 12m ^

FCvl1 2 3 4 / / 5

CO/ T

/A Klhu vc cn cu lm vic

^ / b) B tri tp trung cc b phn

\c) B tr hnh ch u

I

Hnh 4.15: Cc s d h tr b phn sn xut c t thp

71

4.4. B TR TRM SN XUT c p PHA (VN KHUN)

1. M c ch

Vic lp t b tr trm sn xut cp pha cng trng cho php sn xut khun hoc cc b phn cp pha cn thit cho vic btng cc phn mng, ct, dm, tng, tm sn, cu thang... ca cng trnh xy dng v mc ch chung i vi trm sn xut vn khun l thit b phi gim c chi ph nhn cng, ng thi hng ti c gii ho trm. Cp pha c sn xut theo li c truyn hin nay t p dng. Cn s dng cc k thut sn xut cp pha theo mun m bo a s c dng li cc vn khun. Trm sn xut cp pha cng l mt trm sn xut chnh trn cng trng khi c khi lng btng ln.

Tu theo cch t chc sn xut m vic b tr gia cng cp pha trn cng trng c th l:

- Khng c trm sn xut cp pha, nu nh x nghip c mt xng trung tm ch to mi loi cp pha, hoc nh x nghip dng loi vt t c bit sn xut ra cc cp pha cng c. Trong trng hp ny phi b tr nh kho, bi cha tm thi cc loi vn khun sn xut xng hoc nh my vn chuyn n cng trng lp rp.

- Hoc trang b cc thit b c truyn sn xut cp pha nh chng ta bit.

2. S chung ca trm sn xut cp pha

B tr mt trm sn xut cp pha trn cng trng phi m bo:

- C din tch lm kho cha:

- G lm cp pha (g phin, vn...).

- Tm g dn hin dc a dng lm cp pha.

- Cy chng, bng cc dm kiu ng lng v cc tm d kim loi cng hay dng thay th cc loi g trn.

-V n khun c s dng li nhng phi sch s v m bo kh nng chu lc.

- Mt s my cn thit bao gm: ti thiu 1 ca a, 2 my bo, mt s bn v gi gia cng g. Tt c c t trong mt xng sn xut.

- C ngun in cho cc my ca, my bo hot ng (hoc i khi dng ng c xng ko my) v thp sng cho xng c sng m bo khong 5001ux.

- Cc dng c ph tr khc (cc kp vn, my p dp) cho cc inh vt hoc bulng v cc thanh p (ke st, cc st ch U) tng cng ca vn khun.

- Cn c cc xe ra chuyn ch g d tr v xng v cp pha thnh phm vo khu vc lm vic ca cn cu lp vo v tr btng.

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3. Nhng tiu ch co bn chon v tr trm sn xut cp pha

Cng ging nh cc trm btng, trm gia c ng ct thp nu trn, ngoi khi lng cng tc btng ct thp v thi gian cho thi cng, cn c mt s tiu ch c th quyt nh phng thc v tm quan trng ca trang thit b cho xng sn xut cp pha.

La chn v tr t trm: trm sn xut cp pha khng i hi v tr khu t u tin, nhng tt hn ht l ngoi khu vc lm vic ca cn cu. Ngc li mi cu kin lu gi kho c th s dng trc tip c li phi trorm khu vc lm vic ca cn cu.

V tr la chn cho xng qia cng cp pha v cc kho cha k bn khng c lm nh hng n vic qua li ca xe c hoc nhng ngi di b v cho php u ni d dng vi t phn phi in gn nht.

Din tch cng cn tho mn cho vic cha cc loi g v bn thnh phm c gia cng mt phn. Cc my mc v bn thao tc, nu ta chi dng mt ca a th cn mt ch tng i hp. Mt din tch 30m: c th l . trong khi kho cha c th chim 300m2 mi . i vi mt cng trng nh khi lng btng t cng phi c

din tch ti thiu 50 -r 60m2.

Vic b tr cc b phn ca trm sn xut cp pha tham kho trn hnh 4.16. l quy trnh cc thao tc gia cng cp pha, n yu cu s sp xp v cch b tr tuyn tnh c khuyn ngh nh i vi trm gia cng ct thp.

Nn trnh phn tn cc kho cha. t cc my mc gia cng theo mt trt t l gch rt ngn c vn chuyn g v cp pha thnh phm.

V tr cc kho cha:

Vn lm cp pha mi l cc tm dy 25 hoc 30mrn, cc cy ct chng bng g s cht ng v phn loi theo kch thc (tit din, chiu di) t trn khu t cao, phng v c ranh gii r rng. G lu kho c xp theo tng v dc nh s theo thi gian nhp kho tin cho vic s dng sau ny, trnh g trong kho qu di ngy.

Kho g cn trnh c nh hng ca thi tit bng cch lm nh c mi che, m bo thng gi tt.

Nhng li th ca vic gia cng cp pha mt xng tp trung l khng th chi ci uc, bi v mt xng c nh d dng t chc sn xut hn; vn khun c gia cng cn thn, chc chn hn l sn xut chn cng trnh v n c lun chuyn s dng nhiu ln hn. ng thi cng tit kim c g trong qu trnh gia cng cp pha.

Lp t thit b xng cp pha bao gm my x, pha g (ca a v ca thng) v my gia cng (my bo nhn v bo th). Ph bin nht trn cng trng l dng ca a.

73

-p^

Kho cha g lm cp pha

Mi che bng tm tho lp c

Vo

5,00

Ra pha khu vc cu

Bn gia cngLp rp

4,50

Hnh 4.16 : S b tr trm gia cng cp pha

4.5. TRM SN XUT CU KIN BTNG CT THP C SN HOC BTNG D NG Lc

1. M c ch

Vic sn xut cu kin c sn l mc tiu s mt ca cng nghip ho trong xy dng, v n cho php thc hin ' trn mt t, trong cc iu kin m bo cht lng hn, tch ring khu sn xut v lp rp. i vi cng trng c khi lng b tng ln nn b tr xng sn xut btng c sn, c th a n cc khun c sn v cung ng ct thp ti ch, m cn thc y nhanh qu trnh ng cng btng, nhm s dng li vn khun nhanh hn v lun chuyn c nhiu ln.

2. So b tr chun"

C th tham kho s b tr chune trn hnh 4.17.GXng btng c sn phi c xem nh mt on v sn xut, c th ni l c lp

vi phn cn li ca cng trng mc sn xut to ra mt kho cc cu kin c sn, khng b nh hng phin nhiu no trong cc cng vic ca phn xy th. Cho d sn phm c sn thuc loi nh, trung bnh hoc nng th cng ngh u gm cc b phn sau:

- Mt xng sn xut v phn phi btng chung, khng thuc cng trng v btng c sn c cng ngh ring v cp phi cng khng hon ton nh loi btng truyn thng.

- Mt kh vc c c din tch rng ri, dnh cho cc khun c nh hoc lu ng trn cc xe trt. Khong khng gian ny c th hnh thnh mt xng kn 3 bn, hoc c mt phn mi che

- C cc thit b thch hp m bo mi cng vic vn chuyn, lin quan n btng ti v cc cu kin, tho khun: xe rua, cn trc di dng, cn cu, xe ch v.v...

- Mt xng gia cng sn ct thp tlieo tng loi, c trang bi cc my ct, un in, my hn.

- Cc dng c, my mc, thit b nh m rng, m di, m bn, thc; cc thit b hon thin v x l btng nh ni hp, kt gia nhit.

- Mt khu vc bo qun cu kin vi kch thc cha m bo cng vic trong 10 n 15 ngy. Khu vc ny trang b cc gi ta, cc ngn cho php sp xp hp l cc tm c sn ng thi ly chng ra d dng.

- Ngoi ra n n c mt phng th nghim nh kim tra cht lng btng.

3. Cc tiu ch ca trm sn xut btng c sn

Ngoi cc tiu ch ni n nhng trm trn: khi lng cng vic, thi gian thi cng, kho bi, n cn c mt s yu t cu th khc quyt nh b tr mt trm btng c sn. l:

75

cha cp phi cho b tong

My trn ph cho b tng Chiu xe t

Hnh 4.17: V d mt bng xng htng c sn

76

- Tnh cht lp li nhiu ln ca cu kin c sn trong qu trnh thi cng xy dng.

- Sn lng btng c sn hng thng trn cng trng.

- Loi sn phm c sn (nh, trung bnh, nng).

4. Nguyn tc chung b tr

La chn v tr t trm s ph thuc vo:

- Cn trc nng: nu cn trc chy dc theo cng trnh xy dng s dng ng thi c nhiu trm thi cng, v c sn th trm t dc theo ng trc ny. l mt gii php c bit c li, v n cho php:

- S dng cn trc ht cng sut.

- B tr theo tuyn thng l cch b tr l tng i vi mi trm.

Mt s cu kin cho php chng ln nhau chn cng trnh. Nu nh vic sn xut cu kin c sn l quan trng, nhp sn xut khi lng ln, c th b tr my nng chuvn ring (dm cu chy) n c th tp trung xng pha ngoi khu vc lm vic ca cn trc. Trong trng hp ny, t ra cng to nn mt khu vc cha cc cu kin ca cng trnh tm vi ca cn trc dng xy cng trnh.

- Kch thc v ni cc cu kin sn xut: ta c th sn xut cc dm, lanh t cng cao trnh s dng hoc di t, chi cn h mt gian cho mi cao trnh chuyn cc cu kin ln.

V tr c nh ca trm sn xut btng: ngi ta lun lun c ngh rt ngn li cc qu trnh phn b, nhng tm quan trng ca sn xut cu kin c sn c th bt buc phi b tr mt trm trn btng phc v ring cho n.

Vic b tr c lin quan vi cc thit b khc. Cn nhc li d l mt dy chuyn cng ngh, nn di hi trn cng trng t ra cng c mt s b tr tuyn tnh cc trm sn xut, vic b tr trn thc t c th thc hin c vic lp t hp l trm sn xut btng c sn yu cu mt mt phng rt rng. Nu nh n phn tn ra thnh nhiu ni th nng sut c nh hng.

Ngoi ra cn b k thut s b tr trm ny trn nhng tng ch o ca t chc khoa hc v lao ng. C th l:

- Gim n mc ti thiu cc vn chuyn th cng v nh vy cn d kin cc thit b c gii ho di chuyn cc nguyn vt liu, thnh phm: xe phn phi btng chy trn cc khun, khun c khp lt, dm cu chy c palng trng ti 5 n 10T chuyn cc cu kin d cp pha ti khu vc cha sn phm.

- nh v cc bn khun cao thch hp gim nng nhc cho cng nhn.

- D kin mt s khun cho php c s quay vng ti thiu hng ngy. xng s s dng li chng hai ln trong ngy.

77

- Lp nn cc khu cha sn phm theo tng chc nng trong khu vc lm vic ca cn trc dng cho nh ang xy.

- An ton cho trm nht l vn s c in, cc ng cng nhn qua li cn thng thong, tm nhn.

5. Bi c sn

- Cc cng vic chun b: bao gm vic b tr khng gian dnh cho trm v sp t cc khu vc khc nhau ca sn xut.

Dy c, san phng mt t v tiu thot nc to nn cc khu vc sch s btng v cc con ng i li d dng dnh cho xe c v ngi.

Mi vic chun b trn u lin quan n vic lp t trm sn xut btng v trm gia cng ct thp.

- Bi c sn l ni nhng khun c cc cu kin. Khu vc ny l:

Mt bi phng btng trn t cc khun hoc dng chnh n lm khun , khu ny c x l cn thn v cao trnh, nn c rnh thot nc ra cc khun.

- Vn khun c kh nng tho lp theo y u cu sn xut cu kin.

Nhng khun bng g bo hoc bng g dn nh trn hnh 4.18.

Gii hn khu

7,40m

Hnh 4.18: Cc khun t trn tm an btng sn xut dm btng.

Phng thc phn phi btng: Nn lp t thit b c th di chuyn trn bi c sn v dng mt thng y m cha hn hp btng. C th phn phi btng bng cc thng lt chy gia 2 hng khun c.

78

Nn dng xng c mi che c btng s cho ta nng sut cao hn v bo v khi thi tit bt thng i vi cc cu kin va mi tho khun, ng thi thun li cho vic bo dng btng, tng nhanh s ng cng. Khu vc ny c th lm theo dng;

- Ton b di ng trn ng ray t trn tm an ca khu c sn, v c th tho lp, s dng li cc cng trng khc.

- Mi di chuyn c trn cc dm ngang;

- Mi m thng ln, cc khun di chuyn nh cn cu pha ngoi. Nh vy mt cn cu c th m bo mi thao tc gia khu vc c v khu vc kho cha.

Khung nh lm bng g hoc kim loi, mi bng tn hoc cht do ln sng.

6. Kho cha sn phm

Kho cha l mt khu vc lt btng c cao 15 H- 20cm so vi mt t t nhin, bi v vic lu kho trn mt t khng phi lun hp l v cc cu kin d b bn.

N n lm k h o sn phm ngay khi tin hnh IT1 c n g trng v s d n g ch n g tp

kt vt liu chn cng trnh.

Din tch ca kho tu thuc vo chng loi cu kin tp kt v thi hn d kin ng cng trc khi s dng vo lp ghp.

Kho ny cng cn c nhng thit b cho cu kin da, t nh cc gi ta ph hp vi dng cu kin hnh 4.19. Mc ch l sp xp phn loi nhanh chng cc cu kin v ly ra d dng, sp xp theo th t thi gian sn xut tc l tui ng cng ca btng.

Mt thit b nng, vn chuyn cc cu kin t ' kho, thng thng dng dm cu chy l gii php tt hn c. Cng c th dng cn cu thi cng cng trnh vn chuyn, cu kin c sn, nu kho cha sn phm trong tm vi ca cn cu.

y cng nn lu l dm cu chy c th va phc v chuyn btng ti, va a cc cu kin ti kho cha. Dm ny tnh theo tm vi (thng thng t 8 n 15m) v cc ti trng nng, ng thi trang b thm cc pa lng t 5 n 15T.

79

a)Trn cc gin thanh ging

bj Trn cc gi st ch u (hoc o) rh noc g) cho cc cu kin nh

Ch n * 5

T T N G C H O T R O N G T C H C L A O N G

5.1. TH NO L T CHC LAO NG. TAI SAO CAN T CHC LAO NG

T chc lao ng l mt vn lin tc dc nghin cu tm ra phng php ti u s dng kinh t nht ngun nhn lc v cc phng tin khc m bo tnh hiu qu ca x nghip. t c mc tiu nh vy cc cn b t chc lao ng phi:

nh c chnh xc cc phng php thi cng, cch thc vn hnh cho php p dng cc k thut hin i vi thit b v cc cng c c hiu sut cao.

Khng nh c s lng v cht lng nhn vin cn thit, chi ph nh