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ChU'O'llg4 PHUONG pHAp DO HOC KHOI LUQNG vA L~P DV ToAN CONGTRINH
CONGTRINH
Trong chuang miy gim thi~u m\lc dich, yeu cAu,nguyen tAcva phuong phlip do Mc kh6i hrgng cac IO{licong vi~c xay d\lllg va cong trinh xay d\lllg. NQi dung d\f toan, phuang phlip l~p d\f toan cong trinh va xac dinhd\f toan cong trinh bd sung (di~u chinh).
4.1. PHUONG pHAp DO DOC KHOI LU(}NG CONG TRiNH 4.1.1. Khai ni~m, y nghia, myc dich, yeu cAu va nguyen tic
1. Khtii nifm (/0hOc kh6i [U'(lng
Do Mc kh6i lugng xay d\lllg cong trinh, h{lng m\lc cong trinh la vi~c xac dinh kh6i lugng cong tac xay d\lllg C\lth~ duqc thgc hi~n theo phuang thuc do, d~m, tinh toan, ki~m tra tren co sa kich thuac, s6 lugng qui dinh trong ban ve thi~t k~ (thi~t k~ . co sa, thi~t k~ ky thu~t, thi~t k~ ban ve thi cong), ho(ictil yeu cAutri~n khai dg an va thi cong xay d\lllg, cac chi ddn co lien quan va cac tieu chufut, qui chufut xay d\lllg
Vi~t Nam. Do tinh wac kh6i lti'gng wac khi thgc hi~n cong vi~c nen do boc kh6i
lugng con duqc gQi la tien lugng hay do boc tien lugng.
2. Ynghia ciia vifC (/0 hOc kh6i [U'(lng
Kh6i lugng xay d\lllg la din cu quan trQng co tinh chAt quy~t dinh d~n vi~c xac dinh gia tri dg toan va lam can cu quy~t dinh dAutu,chQn phuang an d6i vm chu dAu til va la can cu quy~t dinh phuang an dg thAu cua nha thAu.
Kh6i lugng xay d\lllg cong trinh, h{lng m\lC cong trinh duqc do boc la mQt co sa cho vi~c ki~m soat chi phi, thanh quy~t toan gili tri hqp d6ng thi cong xay d\lllg cong trinh.
Vi~c tinh dung du kh6i lugng ban dAu cong tac xay d\lllg la m6i quan tiim cua nhihlg nguiJi tham gia vao hO{ltdQng dAutil xay d\lllg. Xac dinh kh6i lugng cong vi~c la mQt yeu cAu khong th~ thi6u d6i vai dg an dAu til xay d\lllg cong trinh va la mQt cong vi~c nfun trong trinh tg dAutil xay d\lllg cong trinh.
3. MIlC (/ich ciia vifC (/0hOc kh6i [U'(lng
M\lc dich CCJban cua vi~c do boc kh6i lugng la d6 xac dinh gia thanh xay d\lllg. Ung vm cac giai dO{lnchuan bi dAu til, thgc hi~n dAu til va giai dO{lllk6t thuc xay d\lllg dua dg an vao khai thac sir d\lng thi kh6i lugng cua cong mc xay d\lllg cling duqc xac dinh tIlang fuJ.gdga tren ban ve thi~t k~ CCJsa, thi~t k~ ky thu~t va thi~t k~ ban ve thi congo
Ban kh6i lugng la can cu chu y~u d~ tinh ra yeu cAu v~ kinh phi, v~t tu, nhiin 19c cho cong trinh.
Do boc kh6i IUQllgla trQng tam clla cong mc d\f toan, day la khau kho khan, phuc t\lP va t6n nhieu thm gian nhung l\li tit de sai sot.
4. Yeu eau eua vi~c do-hOc kh6i lU'(f1Ig
a. Kh6i IUQIlgxay d\fng cong trinh phlli duQ'c do, d~m, tinh toan theo trinh t\f phu hQ'Pvm quy trinh cong ngh~, trinh t\f thi cong xay d\fng cong trinh. Kh6i Iuqng do boc cAn the hi~n duQ'Ctinh ch~t, k~t du cong trinh, v~t li~u Chll y~u sir d\lng va phU(JIlgphap thi cong thich hQ'Pdam bao dll dieu ki~n de xac dinh duQ'c chi phi xay d\fng.
Tuy theo dilc diem va tinh ch~t timg 10\licong trinh xay d\fng, kh6iluqng xay d\fng do boc co the ph8.n djnh theo bQ ph~n cong trinh nhu: ph~n ngk (c6t 0.00 tra
xu6ng), phAn n6i (c6t 0.00 tralen), phAn hoan thi~n va phAn xay d\fng khac theo h~g m\lc cong trinh. Kh6i IUQllgxay d\fng do boc clla bQ phAn cong trinh hoilc h~g m\lC
cong trinh duQ'cphiin thlll1hcong tac xay d\fng va cong tac I&pdilt. _
b. Cac thuy~t minh, ghi chu hoilc chi d~ lien quan tai qua trinh do hOc cAnneu ro rang, ng&n gQn, de hieu va dling quy ph\lm, phu hQ'Pvm h6 sa thi~t k€ cong trinh xay d\fllg. Khi tinh toan nhiing cong vi~c cAndien giai thi phai co dien giai C\lthenhu dQ cong vom, tinh ch~t clla cac ch~t li~u ( gil, be tong, kim 10\li...), dieu ki~n thi cong (tren cao, dQ sau, tren c~, dum nuac ...).
c. Cac kich thuac do hOc duQ'c ghi theo thu t\f chieu dai, chieu rQng, chieu cao ( hoilc chieu sau); khi khong theo thu t\f nay pMi dien giai C\Ithe.
d. Cac kY hi~u dung trong bang tinh toan, do hOc kh6i luqng cong trinh, h\lng m\Ic cong trinh phai pM hQ'Pvai kY hi~u da the hi~n trong ban ve thi~t k€. Cac kh6i luqng I~y theo th6ng ke Cllathi~t k~ thi pMi ghi ro I~y theo s6 li~u th6ng ke clla thi~t k~ va chi ro s6 hi~u Cllaban ve thi~t k€ co th6ng k~ do.
d. D(JIl vi tinh my theo yeu cAu quan Iyva thi~t k~ duQ'Cthe hi~n, mili mQt kh6i luqng xay d\fllg se duQ'cxac djnh theo mQt d(JIlvi do phu hQ'Pco tinh tm vm S\f phu hQ'Pcong mc xay d\fng do trong h~ th6ng dinh muc d\f toan xay d\fng cong trinh. D(JIl vi do theo the tich la m3; theo di~n tich la m2; theo chieu dai la m; theo s6 luqng la cai, bQ, d(JIlvi ...; theo trQng luqng la tin, kg...
Vi~c nhk I~ d(JIlvi tinh lam anh huang r~t Ian d~n gia trj d\f toan xay d\fllg cong trinh, gia trj thanh quy~t toan, chi phi d~u tu xay d\fng cong trinh. Truang hQ'P sir dvng d(JIlvi tinh khac vai d(JIlvi thong dvng (Inch, Foot, Square foot...) thi pMi co thuy~t minh b6 sung va quy d6i ve d(JIlvi tinh thong d\lng noi tren.
e. Ma hi~u cong tac trong bang tinh toan, do boc kh6i luqng cong trinh, h\lng m\Ic cong trinh phai phu hQ'Pvai h~ rna hi~u th6ng nh~t trong h~ th6ng djnh muc d\f toan xay d\fllg cong trinh hi~n hanh.
5.Nguyen tde i/o hOe kh8i [U'(TIlg
Khi do boc khdi IUQIlgpMi dain bao cac nguyen t&csau:
a. Tinh dung, tinh dll khdi IUQIlgcac cong tac xay d\lI1gphil hqp vm timg giai dO\lllthi~t k~ (cac buac thi~t k~);
b. Khdi IUQIlgcac cong tac xay d\lI1g duQ'c do boc pMi co don vi do phil hqp vai don vi tinh dinh muc, don gia xay d\lI1gcong trinh;
c. Khdi IUQIlgcac cong tac xay d\lI1g pMi do hOc theo dung chUng 10l;li,qui cach, di~u ki~n kYth~t va bi~n pMp thi cong cong trinh; (adsbygoogle = window.adsbygoogle || []).push({});
d. Khdi IUQIlgcac cong tac xay d\lI1g duQ'cdo hOc pMi thu~ 19i trong vi~c ap gia khi xac dinh gia tri tdng muc dAuill, d\l toan xay d\lI1gcong trinh;
d. Khi do boc khdi Iu~g cong tac xay d\lI1g cAn v~ d\lIlg cach dlic thira sd chung cho cac bQ ph~ gidng nhau, holic dung kY hi~u de sir d\lIlg Il;linh~m giam nh~ khdi IUQIlgcong vi~c tinh toan;
e. T~n d\lng sd li~u do hOc clla cong tac truac cho cong tac sau, k~t hqp khdi IUQIlgclla cong tac gidng nhau de giam trir.
4.1.2. Phll'O'Dgphap do hOc khAi Ill'qng cac lotli cong vi~c
l.N€nmong
N~n mong la phAn dAt da nb dum d~ mong, chiu toan bQ tai trc,mgClla cong
trinh de xudng. Can cu vao cAutl;lOCllacac 16p dAtda Cllatirng khu V\lCdia chAt ngu<ri ta co nhUng phuong an xir Iy khac nhau. Co the phan n~n mong thanh hai 10l;liIa n~n mong t\l nhien va n~n mong nhiin tl;lO:
- N~n mong t\l nhien: Cho phep khong phai gia cd nhll'llg viin dam bao suc chiu tai do cong trinh gay ra;
- N~n mong nhiin tl;lO:DAt t\l nhien khong dam bao chiu tai do cong trinh gay ra thi nguai ta phai gia cd ruc la dUQcchuyen thanh n~n mong nhiin tl;lO.
Co cac hinh thuc gia cd n~n mong:
- Gia cd n~n mong b~g vi~c dd them vao n~n cac lap da, cat vang ....
- Gia cd n~n mong b~g cac 10l;liCQC:CQCtre, CQCg6, CQCbe tong cdt thep, CQC cat.
a. Do boc khdi Iuong cong tac san xuAt CQCbe tong cdt thep: +Don vi tinh: m3
+Quy cach:
- Kiem tra ban ve thi~t k~ chi ti~t CQCva bang thdng ke cdt ~hep CQC,kich thuac hinh hQc, kich thuac ban rna dAuCQC,sd dai CQC,cac lap dum dAu CQC...
- Mac be tong dQc trong phAn ghi chu ban ve chi ti~t. - Da dung lam CQCIx2, 2x4 ...
(4.1)
(4.2)
(4.3)
+ Phuang phap do boc
- Tinh khai lugng be tong bfutg cach chia CQCtheo cac hinh hQc thich hQP. CQc chia lam 210\1i Cl va C2
* CQc C I gam dO\1nthan va mlii DO\lllthan (V,):
V, =B'xLjxn (m3)
Trong do:
B: ChiSu rQng; CQC;
Lj: ChiSu dai dO\1nthan CQC; n: sa lugng CQC.
DO\lllmlii (Vm):
Vm=~(B'xL,xn) (m3)
Trong do: B; n: Nhu tren;
L2: ChiSu dai dO\lfimiii CQC; (adsbygoogle = window.adsbygoogle || []).push({});
* CQc C2:
V, =B'xLxn (m3)
Trong do: B; n: ~hu tren; L: ChiSu dai CQC;
- Do boc cong tlic gia cong va l~p d\lllg van khuon CQCbe tong duc siin tinh d\l'a tren di~n tich bS m(it cua be tong CQC(chu y dan vi cua van khuon khi tinh la
100m2).
- Do boc khai lugng gia cong va I~p d\lllg cat thep CQCbe thOng duc siin din Clr vao hinh ve tri~n khai tren cac m(it c~t chi ti~t cua CQCva I~y bang thang ke cat thep lam din Clrki~m tra. cAn phan thanh thep co d:s 10mm, d:s 18mm va d> 18mm.
b. Cong tac dong CQCbe tong cat thep:
+Dan vi: 100 m..
+Quy cach: cAn xac dinh ro nhUng d(ic di~m sau:
- Sir d\mg bUa may co trQng lugng dliu bua :s 1,8 tAn,> 1,8 t~ ... - Quy cach, kich thuac: ChiSu dai CQC,ti~t di~n CQC.
- C~p d~t da va diSu ki~n thi cong: C~p d~t 1,2 va tren C\1n,duai nuac. - Bi~n phlip thi cong: Dong CQC,epcQc ...
(m) (4.4)
(4.5) Trong do:
:ELc:TAng chi~u dili C9C; hi:DQ sau mQt 16C9C;
nj: Tom bQ s6 16C9C
+ Ten cong vi~c thuimg co:
- Dong C9Cbe tong c6t thep, tith di~n (20x20)cm, tr9ng lugng dAu bila::; 1,2T. ~Dong C9Ctong c6t thep, tilh di~n (3Ox30)cm, tr9ng lugng dAublla 2: 1,8T. - Ep truac C9Ctong c6t thep, ti~t di~n (I OxIO)cm ...
- Ep sau C9Ctong c6t thep, ti~t di~n (40x40)cm ...
- ...vv
c. Cong tac dong C9Ctre, g6...:
+Dan vi: 100 m.
+Quy cach:dn xac dinh ro nhiing d~c di~m sau: - LO\liv(it Ii~u: C9Ctre, C9Cg6, C9Ctram, Cll g6 ... - Nhom dAt: blm, dAtcApmAy.
- Kich thuac v(it Ii~u: C9C::;2,5m ; C9C2: 2,5m. - Bi~n phap thi cong: Thil cong ho~c bAngmay.
+Phuang phap tinh:
IL, =F., xL, x md (m)
Trong do:
:ELc:TAng chi~u dai C9C; Fgc: Di~n tich gia c6; Lc: Chi~u dai C9C;
md: M(it dQ C9C(s6 c9clm2).
+Ten cong vi~c thuimg co: - Dong C9Ctre;
- Dong C9Cg6; - Dong C9Ctram; - ... vv. (adsbygoogle = window.adsbygoogle || []).push({});
2. Cong tac dtit
a. Dan vi: 100m3 d6i vai cong tac dao bAng may va m3 d6i vai cong tac dao bAngthil congo
(4.7)
(4.8)
+ C~p ddt: Co th~ xem phAnthuy~t minh ban ve d~ bi~t duQ'cd~t dao mong Clla cong trinh thu(lc lo~i c~p d~t nllO.Kho hay d~ thi congo .
+Kich thuac: DBi vm cong tilCdao mong tuemg, muong, ranh thi: - Chi~u r(lng quy djnh t~i hai cAp:'53m va >3m;
- Chi~u sau quy dinh vm m6i c~p bAng lm::'51 m, :'52m,:'53m,>3m; - Mong hB d(lc l~p phiin theo b~ r(lng.
C.Phuong phap tinh: Kich thuac h6 dao duQ'cxac dinh dva tren kich thuac m(it bAngva m(it dt chi ti~t mongo
+Cong thuc tinh khBi lUQ'l1gkhBi hinh chop C\lt:
V= ~x[axb+dxc+(c+a)x(d+b)J (m3) (4.6)
+Tinh khBi lUQ'l1gmong bAng co taluy cAn chia c~t thllnh cac hinh don gilin d~ tinh.
+Tinh khBi lUQ'l1gl~p mong: - Tinh chinh xac:
V'ip =Vdao - Vc6ngtrinhbichonglap
- Tinh gAn dung theo kinh nghi~m: VI;p =iV<lao (m3) d.Ten cong vi~c thuemg co:
+Dao mong c(lt, dao mong bang cac lo~i;
+Dao n~n duemg;
+L~p d~t mong cong trinh;
+D~p d~t n~n nha;
+D~p cat pM dau Cll'
3. Cong tticbetong
a. Don vi: m3
b. Quy cach: Trong cong tac be tong cAn duQ'cphiin bi~t:
+Lo~i be tong: Be tong g~ch va, be tong lot mong, be tong co cBt thep hay be tong khong co cBt thep;
+SB hi~u be tong (be tong g~ch go, mac vua be tong);
+Lo~i cAuki~n;
+Vi tri cAuki~n;
+Phuong thuc d6 be tong. c. Phuong phap tinh
. - TniOD.gllgp 1: CQt co tiSf di~n ran.hari dim. thi 6etong cQttfnli tiUiJCva be
tong dAm tfnh sau. ChiSu dii cQt tfnh suat va chiSu dBi dAm trir ctmh cQt;
- Tnrc'mg hqp 2: CQt co tiSt di~ bing dAm thi be tong cQt hay be tong dAm tfnh tnWc dSu dugc, OOung nen tfnh be tong dAm tnrac fbi phil hqp vm qua trinh fbi cong han; (adsbygoogle = window.adsbygoogle || []).push({});
- Troc'mg hgp 3: CQt cO tiSt di~ 006 han dAm thi be tong dAmtfnh troac, be tong cQt tfnh sau. ChiSu dBi dim tfnh suat va chiSu cao cQttrir chiSu cao dAm.
+Cong tlic be tong san, mai: Khi do boc khai luQIlg be tong san, mai phsi chia tach th8nh timg san, maio Trong timg san, mai I~ chia th8nh cac san dan gian va cac san phuc 41p. Co the chia san ra th8nh cac hinh don gian cling cach tfnh. Di~n tich san, mai nen tfnh ca di~ tich dAm, trir di di~n tich cQt, trir di~ tich cae 16r6ng ... Di~ tich nay de II,Yid\ll1g cae tfnh toan cac khai IUQIlgc6ng tac khac.
+ Congtlic be tong xi, dAm, giing: Cong tlic be tong xi, dAm, giAng dUQc do
hOc theo nguyen Mc dAm nao co tiet di~ Ian han dugc tfnh tnrac. DAm co tiet di~
006 dUQctfnh sau. Khi tim kich thu6c dAm phai can cu vao ban vern,t bAng ket cAu, hiOOve trien khai Clla dAmdo de trir di phin giao cho chfnh xae
4. Cong lac c61 IMp
a. Don vi: TAn.
b. Quy caeh: cAn phan bi~t:
+Lo~i thq,;
+Kich thuac dai vm thep hiOO;
+Duc'mgkfnh dai vm thep trim;
+Lo~ cAuki~ va vi tri cAuki~n;
+Phuong phap thi congo C.Phuong phap tinh
+ Cong tac cat thep CQt:Cong tac gia cong va lAp d\lllg cat thep CQt,cong tac nay dugc do Mc d\la v~o kich thu6c hinh ve trien khai cua timg lo~i cQt (chu y den chiau dBi cua thq, cho bi~n phap thi cong do 8nh huang cua chiau dai cac do~ nai gifra cae thanh thep). Tuy nhien ding co the can cu vao bang thBng ke trong hd sa
thiet ke nhung nhAt thiet phili kiem tra tfnh chiOOxae b~g vi~c dBi chil~u vai hiOOve chi tiet va tinh toano
+ Cong tlic cdt thep san, mai: Cong tlic san xuAt va lAp d\lllg cBt thep san mai duqc do Mc d\la vilo kich thucrc hinh ve trien khai Cllatimg lo~i san, thep lap tren, lap
dum,thep momen ... (chu y den chiau dai Clla thep cho bi~n phap thi cong do ilnh
vao bang th6ng ke trong h6 so thiSt kS nhung nhAt thiSt pMi ki~m tra tinh chinh xac bfutg vi~c d6i chiSu vOi hinh ve chi tiSt va tinh toano
+ Cong tac c6t thep xa, db, gifutg: Cong me san xuAt, I&pd\IDg c6t thep xa, db, gifutg dugc do boc d\Ia vao kich thuoc hinh ve tri~n khai cua tUng xit, db, gifutg. (chu y dSn chi~u dai cua thep cho bi~n phiip thi cong do imh huimg cua chi~u dai cae do~ n6i giua cae thanh thep). Tuy nhien ciing co th~ din cir vao bang th6ng ke trong h6 so thiSt kS nhung nhAt thiSt pMi ki~m tra tinh chinh xac bfutg vi~c d6i chiSu voi hinh ve chi tiSt va tinh toano
Tinh kh6i lugng 1m thep tron theo cong thirc:
M=0,6165xDxD (Kg) (4.9)
Trong do:
M: Kh6i lugng 1m thep tron; D: Duimg kinh c6t thep (em)
Chu y: D6i vOi thep hinh lilm Ian can, cAu thang c~ co bang tra tiSt di~n va trQng lugng cua 1m dai til do tinh toan kh6i lugng ho(ic tinh theo cong thirc:
L M=LxFxnx7850 (Kg) (4.10)
Trong do:
M: Kh6i lugng cAuki~n thep hinh; L: Chi~u dai cAuki~n thep hinh (m); n: S6 lugng cAuki~n thep hinh;
TrQng lugng rieng ella thep hinh =7850kg/m3•
5. Cong tac san xuat, Nip dlplg kit cau siit thep
a. C~ xac dinh ro nhung d(ic di~m sau: (adsbygoogle = window.adsbygoogle || []).push({});
+Dan vi tinh: I tAn;
+ChUng 10llithep: Thep hinh, thep tAm,thep tron ...;
+LOlli cong tac: Sim xuAt vi keo, I&pd\IDg vi keo, san xuAt xa g6, I~p d\IDg xa g6, san xuAt gifutg thep, I&pd\IDg gifutg thep, san xuAt thep Ian can cAuduimg sk ..;
+Quy each, kich thuoc cAuki~n: Van khuon khAu dQ:S 36m, :s9m;
+Cae ki~u lien kSt: Han, bu long ...;
+Bi~n phap gia cong: CogiOi, thu cong ... b. Phuong phiip tinh:
+Tinh theo bang th6ng ke thep cua ban ve thiSt kS;
+ Ho(ic tinh tf\Ic tiSp til thiSt kS cAu ki~n: Truoc khi tinh c~ phiin bi~t cae thOng s6 C<Jban nhu:
- Kich thuoc: Dai x rQng x day (d6i voi thep hinh, tAm); - Kich thuoc: Dili x duimg kinh (d6i vOi thep tron) ...
Tinh chh~u dai cAuki~n x di~n tich cAuki~n x sa lugng cAu ki~n x trQng lugng rieng.
Vi dy:
Tinh khai lugng gifulg mai, g6m 12 cAu ki~n, dai 5,5m, ton d~p, kich thuac C200 x 50 x 15 x 2,5.
Tinh M= 5,5 x (0,2 +0,05 x 2 +0,015 x 2) x 0,0025 x 12 x 7850 = 427,43kg '" 0,43 tAn. (Tn;lOglugng rieng clla thep: 7,850kglm3).
c. Ten cong vi~c thuimg co:
+San xuAtk~t cAuthep: Vi keo, xa g6, gifulg ;
+L~p d\ffig k~t cAuthep: Vi keo, xa g6, gi~ng ;
+.V.v ...
6. Cong tae van khuon (cat ph a)
a. Don vi tinh: 100m3
b. Quy cach: dn cM yphan lo~i:
+Van khuon bfulg gil;
+Van khuon bfulg kim lo~i; c. Phuong phap tinh:
+Cong tac van khuon cQt:
Cong tac gia cong I~p d\ffig van khuon v~ trinh tv"thi cong thi cong tac nay lam tfUac khi dd be tong nhung khi hOc khai lugng lqi d\lng k~t qua cong tac be tong. Khai lugng van khuon duqe tinh dga vao di~n tich m(it ngoai clla be tong cQt b~ng