Kev Xam Cov Khoom Siv Rau Cov Qauv Pob Zeb Uas Muaj Zog
Kev xam cov khoom siv uas xav tau rau cov qauv pob zeb ua vaj tse yog ib kauj ruam tseem ceeb hauv kev npaj thiab kev siv cov haujlwm tsim kho. Kev xam kom raug yuav cuam tshuam rau kev siv nyiaj kom zoo, kev yuav khoom raws sijhawm, thiab qhov zoo ntawm kev ua haujlwm hauv daim teb. Kev tsis txaus cov khoom siv tuaj yeem ua rau kev ua haujlwm qeeb, thaum cov khoom siv ntau dhau yuav ua rau cov nqi nce ntxiv, tsim cov khib nyiab, thiab ua rau kev khaws cia ntau ntxiv. Tsab xov xwm no tham txog cov ntsiab lus yooj yim, cov kauj ruam xam, thiab cov piv txwv ntawm cov txheej txheem siv rau kev xam cov khoom siv uas xav tau rau cov qauv pob zeb ua vaj tse.
1. Cov khoom siv hauv cov pob zeb ua vaj tse
Feem ntau, cov qauv pob zeb ua vaj tse muaj ob pawg tseem ceeb ntawm cov ntaub ntawv:
1. Pob zeb ua vaj tse: sib tov ua ke ntawm cov cement, cov xuab zeb me me, cov pob zeb loj (pob zeb xuab zeb/pob zeb tawg), dej, thiab, yog tias tsim nyog, cov tshuaj ntxiv. Cov kev xav tau ntawm pob zeb ua vaj tse feem ntau yog xam ua cov chav ntim (m³).
2. Cov hlau txhawb zog: muaj cov hlau txhawb zog tseem ceeb, cov hlau txhawb zog shear (stirrups/spirals), thiab cov hlau txhawb zog faib lossis cov hlau txhawb zog shrinkage. Cov hlau uas yuav tsum tau muaj yog xam ua qhov hnyav (kg lossis tons) thiab ntev (m).
Tsis tas li ntawd xwb, muaj cov ntaub ntawv txhawb nqa xws li cov formwork (ntoo, plywood, steel forms), hlau khoov, spacers, thiab curing compound. Txawm li cas los xij, qhov tseem ceeb ntawm kev xam cov khoom siv hauv cov pob zeb reinforced feem ntau yog qhov ntim ntawm cov pob zeb thiab qhov hnyav ntawm cov hlau reinforced.
2. Cov ntsiab cai yooj yim ntawm kev xam qhov ntim ntawm cov pob zeb ua vaj tse
Kev suav cov ntim ntawm cov pob zeb feem ntau ua raws li cov qauv geometric rau cov khoom siv hauv tsev. Qee cov khoom siv uas feem ntau suav yog:
– Slab: Ntim = ntev × dav × tuab
– Beam: Ntim = ntev × dav × siab (lossis qhov ntev ntawm beam)
– Kem: Ntim = thaj tsam seem × qhov siab
– Lub hauv paus ntawm lub hauv paus: Ntim = ntev × dav × tuab (lossis cov duab trapezoidal/stepped raws li tus qauv tsim)
Thaum twg txiav txim tau qhov ntim ntawm cov pob zeb tiav lawm, cov neeg npaj feem ntau ntxiv qhov pov tseg lossis qhov kam rau ua haujlwm. Qhov ntau npaum li cas nyob ntawm qhov nyuaj ntawm txoj haujlwm thiab txoj kev casting, tab sis feem ntau yog li ntawm 2-5% rau kev ua haujlwm huv si, tswj tau thiab tuaj yeem siab dua yog tias cov xwm txheej ntawm thaj chaw tsis zoo.
Ib qho piv txwv luv luv
Piv txwv li, ib lub floor slab ntsuas 10 m × 8 m nrog tuab ntawm 0,12 m:
– Ntim = 10 × 8 × 0,12 = 9,6 m³
Yog tias cov khib nyiab yog 3%:
– Qhov ntim tsim = 9,6 × 1,03 = 9,888 m³ ≈ 9,89 m³
3. Hloov qhov ntim ntawm cov pob zeb ua vaj tse mus rau hauv cov khoom siv uas xav tau (cement, xuab zeb, pob zeb, dej)
Hauv thaj teb, cov pob zeb ua vaj tse tuaj yeem tau txais los ntawm ob txoj hauv kev tseem ceeb:
1. Cov pob zeb sib xyaw ua tiav lawm: cov kev xav tau tsuas yog teev nyob rau hauv m³ raws li qhov zoo (piv txwv li K-250, fc' 20 MPa, thiab lwm yam).
2. Cov pob zeb sib xyaw ua ke hauv qhov chaw (sib xyaw ua ke ntawm qhov chaw): qhov ntim ntawm cov pob zeb yuav tsum tau muab faib ua cov khoom siv uas xav tau.
Rau qhov chaw sib tov, cov khoom siv uas yuav tsum tau muaj nyob ntawm qhov tsim cov khoom sib tov. Ib txoj hauv kev yooj yim feem ntau siv cov lus qhia sib xyaw rau 1 m³ ntawm cov pob zeb ua vaj tse. Ua ib qho kev qhia dav dav (cov nqi yuav txawv nyob ntawm cov qauv, cov ntaub ntawv, thiab cov hom phiaj zoo), cov kev xav tau rau 1 m³ ntawm cov pob zeb ua vaj tse nruab nrab yuav nyob rau hauv cov hauv qab no:
– Cement: 300–400 kg
– Xuab zeb: 0,45–0,55 m³
– Pob zeb: 0,70–0,85 m³
– Dej: 160–210 liv
Vim muaj qhov sib txawv ntau, nws yog qhov zoo tshaj plaws los siv cov qauv sib xyaw ua haujlwm lossis kev tsim qauv sib xyaw ua haujlwm hauv chaw kuaj mob. Txawm li cas los xij, rau kev kwv yees nyiaj txiag thawj zaug (RAB), feem ntau siv cov txheej txheem teev.
Kev piav qhia ntawm txoj hauv kev
Yog tias siv 350 kg ntawm cov cement, 0,5 m³ ntawm xuab zeb, 0,8 m³ ntawm cov pob zeb, thiab 180 liv dej rau 1 m³ ntawm cov pob zeb ua vaj tse, ces siv 9,89 m³:
– Cement = 9,89 × 350 = 3.461,5 kg ≈ 3,46 tonnes (≈ 69 zak @ 50 kg)
– Xuab zeb = 9,89 × 0,5 = 4,945 m³
– Pob zeb = 9,89 × 0,8 = 7,912 m³
– Dej = 9,89 × 180 = 1.780,2 liv
Ntxiv cov khoom pov tseg yog tias tsim nyog, tshwj xeeb yog xuab zeb thiab pob zeb (piv txwv li 5–10%) vim yog kev tuav thiab kev poob hauv thaj teb.
4. Kev suav cov kev xav tau ntawm cov hlau txhawb nqa
Tsis zoo li cov pob zeb ua vaj tse uas yog raws li qhov ntim, cov hlau reinforcing yog xam los ntawm:
- tus naj npawb ntawm cov ceg,
- qhov ntev ib tus pas nrig,
- txoj kab uas hla ntawm lub zog txhawb nqa,
- qhov hnyav ib 'meter' (kg/m2).
4.1 Qhov hnyav ntawm cov khoom siv txhawb nqa ib 'meter'
Feem ntau, qhov hnyav ntawm cov hlau yog 7.850 kg/m³. Hauv kev xyaum, qhov hnyav kwv yees ntawm cov hlau txhawb nqa ib 'meter' tuaj yeem suav tau siv cov qauv hauv qab no:
Qhov hnyav (kg/m2) = 0,006165 × d²
d hauv mm.
Piv txwv:
– D10: 0,006165 × 10² = 0,6165 kg/m2
– D13: 0,006165 × 13² = 1,042 kg/m2
– D16: 0,006165 × 16² = 1,579 kg/m2
– D19: 0,006165 × 19² = 2,224 kg/m2
Tus nqi no ze rau lub rooj txheem uas cov neeg kwv yees feem ntau siv.
4.2 Cov kauj ruam los xam cov kev xav tau ntawm kev txhawb nqa
1. Txheeb xyuas daim duab ntawm cov qauv: txoj kab uas hla, tus lej, qhov sib nrug, thiab qhov ntev ntawm kev khi lossis kev sib txuas ntawm lub voj voog.
2. Xam qhov ntev ntawm cov khoom siv txhawb nqa raws li qhov loj ntawm cov khoom ces ntxiv rau:
- qhov ntev ntawm tus nuv (nuv) yog tias muaj,
– lub sijhawm ntawm kev faib tawm,
- qhov ntev ntawm kev sib tshooj ntawm cov pob qij txha,
- ntxiv rau kev khoov.
3. Xam tag nrho qhov ntev = tus naj npawb ntawm cov pas nrig × qhov ntev ib tus pas nrig.
4. Kev hloov pauv mus rau qhov hnyav = tag nrho qhov ntev × qhov hnyav ib 'meter'.
5. Ntxiv cov khib nyiab (feem ntau yog 3–7%) rau cov khoom txiav thiab cov khoom seem.
Piv txwv lub tswv yim rau ib lub block
Piv txwv li, ib lub nqaj ntev 6 m muaj kev txhawb nqa hauv qab 4D16 tas mus li. Xav tias txhua lub bar xav tau ntxiv 0,4 m ntawm kev txhim kho ntawm txhua qhov kawg (qhov no tsuas yog rau kev piav qhia xwb; cov nqi tiag tiag yog raws li qhov yuav tsum tau tsim).
– Qhov ntev ib tug pas = 6 + 0,4 + 0,4 = 6,8 m
– Tag nrho ntev = 4 × 6,8 = 27,2 m
– Qhov hnyav D16 = 1,579 kg/m2
– Tag nrho qhov hnyav = 27,2 × 1,579 = 42,95 kg
Rau cov stirrups, qhov kev suav feem ntau yog:
– txiav txim seb muaj pes tsawg tus stirrups = (qhov ntev / qhov sib nrug) + 1,
- xam qhov ntev ntawm 1 lub stirrup = qhov ncig ntawm lub net + cov hooks ntxiv,
- muab ntau, tom qab ntawd hloov los ntawm qhov hnyav ib 'meter'.
5. Tej yam uas feem ntau tsis nco qab thaum kwv yees
Yuav kom xam tau cov khoom siv kom raug dua, cov hauv qab no yuav tsum tau xav txog:
1. Qhov tuab ntawm cov pob zeb npog cuam tshuam rau qhov ntev ntawm cov stirrups thiab qhov ntev ntawm cov reinforcement.
2. Qhov ntev ntawm cov pob qij txha faib thiab cov pob qij txha lap tuaj yeem ua rau kev siv hlau ntau ntxiv, tshwj xeeb tshaj yog rau cov ntsiab lus ntev.
3. Qhov sib txawv ntawm qhov ntev ntawm lub Hoobkas (feem ntau yog 12 m). Kev txiav ntawm 12 m bar ua rau muaj cov khoom pov tseg uas siv tsis tau tas li.
4. Kev hloov pauv rau tus qauv tsim teb (kos duab hauv khw) xws li hloov qhov qhib, hloov cov ntsiab lus txuas, lossis xav tau kev txhawb nqa ntxiv.
5. Qhov zoo ntawm cov formwork thiab casting txoj kev cuam tshuam rau cov khib nyiab ntawm cov pob zeb (cov dej nchuav, cov dej xau, thiab lwm yam).
6. Hom kev txhawb zog (dawb/xov) thiab cov xwm txheej khoov uas cuam tshuam rau cov ntsiab lus ntawm qhov ntev ntawm tus nuv.
6. Cov txheej txheem ua tau zoo: kev rov ua dua thiab kev teem sijhawm khoov bar (BBS)
Rau cov haujlwm uas muaj cov qauv zoo dua, cov kev xav tau ntawm kev txhawb nqa raug suav los ntawm kev siv Bar Bending Schedule (BBS), uas yog cov npe ntawm cov kev txhawb nqa uas muaj:
- barcodes,
- duab,
– txoj kab uas hla,
- qhov ntev ntawm kev txiav,
- tus nqi,
– tag nrho qhov ntev,
- qhov hnyav tag nrho.
Nrog BBS, kev yuav hlau ua kom raug dua, ua rau kev tsim khoom yooj yim dua thiab txo cov khib nyiab. Rau cov pob zeb ua vaj tse, kev suav cov ntim rau ib qho khoom (kab, ntoo, pob zeb, ntaiv) feem ntau yog sau ua ke rau ib pem teb lossis ib cheeb tsam casting kom sib haum nrog cov txheej txheem casting.
7. Xaus Lus
Kev xam cov khoom siv uas yuav tsum tau siv rau cov qauv pob zeb ua vaj tse yog raws li ob yam tseem ceeb: qhov ntim ntawm cov pob zeb thiab qhov hnyav ntawm cov hlau ua vaj tse. Qhov ntim ntawm cov pob zeb ua vaj tse yog xam los ntawm cov ntsiab lus geometric thiab ntxiv cov khoom pov tseg tsim nyog. Lub caij no, cov khoom siv ntxiv yog xam los ntawm cov duab kos duab ntxaws ntxaws (tus lej, txoj kab uas hla, qhov sib nrug, thiab cov ntsiab lus txuas thiab kev sib txuas) thiab tom qab ntawd hloov mus ua qhov hnyav siv qhov hnyav ib 'meter'. Txhawm rau kom ua kom raug thiab txo qhov pov tseg, kev siv BBS rau kev ntxiv dag zog thiab rov qab ntim ib cheeb tsam casting yog qhov pom zoo heev. Hauv cov theem pib, kev kwv yees ntxhib yuav siv txoj hauv kev tabular, tab sis raws li kev siv, kev xam yuav tsum xa mus rau cov duab kos ua haujlwm kawg thiab cov ntsiab lus npaj kom ntseeg tau tias muaj cov khoom siv raug dua, ib qho project zoo dua, thiab tswj cov qauv zoo.
