N CNG NGH XY DNG CNG TRNH B TNG

N MN HCCNG NGH XY DNG CNG TRNH B TNGContentsChng 1:Ti liu cho trc31.1 c trng kt cu cng trnh31.2 c im v kh hu thy vn31.3 c im a hnh, a cht.31.4 Vt liu xy dng31.5 Vt liu lm vn khun31.6 c im thi cng cng trnh4Chng 2:Nhim v n42.1 Thuyt minh tnh ton:42.2 Bn v42.3 Tin thc hin4Chng 3:Phn tnh ton53.1 Tnh ton khi lng b tng li trn v cc phn khc53.2 Phn chia t, khonh b tng, xc nh cng thi cng53.2.1Nguyn tc chung:53.2.2Phn t b tng53.3 D tr vt liu:6Chng 4:Tnh ton cp phi b tng74.1 B tng M20074.2 Xc nh st ca b tng (Sn)74.3 Chn t l N/X:74.3.1Xc nh liu lng pha trn8Chng 5:Tnh ton chn my trn105.1 Chn loi my trn:105.2 Xc nh nng sut thc t ca my trn:115.3 B tr mt bng trm trn125.3.1B tr trm trn.125.3.2Tnh ton vn chuyn ct liu125.3.3Tnh ton s xe vn chuyn va b tng135.4 Tnh ton s xe vn chuyn va b tng bng t145.4.1Tnh s t145.5 , san, m, v dng h b tng165.5.1 b tng165.5.2San b tng165.5.3m b tng165.5.4Tin hnh dng h b tng165.6 Kim tra kh nng pht sinh khe lnh i vi khonh in hnh175.6.1iu kin khng pht sinh khe lnh175.6.2Kim tra iu kin khng pht sinh khe lnh185.7 Thit k vn khun, cch lp dng vn khun cho khonh in hnh195.7.1Cc loi ti trng195.7.2Thit k vn khun205.8 Tho d vn khun v lp dng vn khun:245.8.1Lp dng vn khun245.8.2Tho d vn khun :24

Ti liu cho trc0. c trng kt cu cng trnhCng trnh l mt tr x l, s on dc nc 2, chiu di on dc nc 18, b rng dc nc 8. B tng li trn M150. B tng lt M100, c chiu dy 10cm. Cc b phn khc s dng b tng mc 200c im v kh hu thy vnCng trnh c xy dng vng ng bng Ty Bc c hai ma r rt:Ma ma t ngy 1/5 n 30/10.Nhit trung bnh l 270C, cao nht l 350C, thp nht l 370C. m trung bnh hng nm W = 80%c im a hnh, a cht.Trn nm trn a cht tt. Bi tp kt vt liu my mc thun tin t nn khng cn x l khi xy dng cng trnh.Vt liu xy dngXi mng, st thp, ct, mua cch cng trnh khng xa v c th m bo v cht lng v s lng, gi thnh. S dng xi mng PC40.Bang 1:Cc ch tiu Xi mng, ct nh sau

Vt liu m W%Dung trng ring (T/m3)Dung trng t nhin kh 0(T/m3)

Xi mng (P)03.11.25

Ct32.651.45

12.701.55

Vt liu lm vn khunVn mt dung thp dy 0,5cm, dm ph dng thp C120, dm chnh dng thp 2C120Tnh ton vn khun Tngc im thi cng cng trnhCng trnh thi cng trong 6 thng ma kh. n v thi cng cc thit b v nhn lc cn thit theo yu cu.

Nhim v nThuyt minh tnh ton:+ Tnh ton khi lng v d tr vt liu.+ Tnh ton cp phi cho b tng M200+ Phn chia t, khonh b tng v xc nh cng thi cng.+ Xc nh my trn v s lng cn thit.+ Xc nh cng c vn chuyn vt liu v b tng.+ Phng php v kim tra khng ch khe lnh.+ Thit k vn khun cho mi khonh c th.Bn v+ Phn chia t, khonh b tng ( ct dc, mt bng, cc mt ct)+ B tr phng n b tng cho mt khonh in hnh.+ Bng khi lng, biu cng .+ Cu to vn khun tiu chun v cch lp dng.Tin thc hin

N CNG NGH XY DNG CNG TRNH B TNG

SINH VIN: BI VN QUNGPage 24

Phn tnh tonTnh ton khi lng b tng li trn v cc phn khcQua phn tnh ton ta tnh c khi lng b tng M200 l 2766,47 m3, v khi lng phn li trn M150l 469,11 m3. Phn chia t, khonh b tng, xc nh cng thi cngNguyn tc chung: Vic phn chia khonh cn phi hp l, m bo v cht lng, v tng tc thi cng, trnh hin tng pht sinh khe lnh, khe nt trong cu kin b tng, cn trnh hin tng nt b tng, to iu kin cho b tng thot nhit tt, do vy, khonh b tng khng c qu ln, cn tn dng thi gian b tng hp l, trnh thi tit qu nng, nu phi thi cng trong iu kin bt buc, cn c bin php gim nhit cho khi b tng. Cc yu t phn chia khonh , t hp lHnh dng kt cu.Khi lng b tng.Khe kt cu, khe thi cng.Thi gian thi cng l 6 thng ma kh.Khi lng cc t b tng phi xp x bng nhau, chnh lch gia cc t l khng ln, trnh pht sinh khe lnh, b tr nhn cng, thit b my mc ph hp.Cc khonh trong cng 1 t khng qu xa nhau, gim thi gian i li, tn cng sc, chm tin thi cng.Phn t phi t di ln trn, t trc v sau, trnh thiu stThng thng cc khonh nm cnh nhau ta thng thi cng vo cc t khc nhau.Phn t b tngS t c tnh theo cng thc: (t)

Trong :N l s t b tngM l s ngy thi cng thc t. Vi thi gian l 26 ngy/thng ma khT l s ngy b tng trong 1 t. T = 6 ngy. Vy N 26 tKhi lng va cho tng t :Vva = 1.025Vthnh khChn 1ca = 8 gi. Mt thng b tr 5 t , mi t ko di 6 ngy. b tng trong 1 ngy phi tnh lm vic 3 ca. Mt t ti a 3 ca, mi ca ch c 6 gi b tng cn 2 gi lm cng tc chun b nghim thu...Cng b tng tng t: (m3/ca)Trong :Q l cng b tngVva l khi lng va cho khonh t l thi gia thi cng (ca)Hinh 1:Biu cng BT theo t

Chn cng BT thit k:Qtk = Qmax =124m3/ca

D tr vt liu:Bang 2: D tr vt liu

+ Tra nh mc 1776: nh mc cp phi vt liu cho 1m3 b tng:- st : 14 17 cm- d max = 40mm [(40 70)% c 1x2 cm v (60 30)% c 2x4 cm STTMc BTKhi lng(m3)nh mc D tr

Ct(m3) (m3)Xi mng(kg)Ct(m3)(m3) Xi mng(kg)

1150469,110,5420,842235254,258394,991110240,85

22002766,470,5220,8312841444,0972298,937785677,48

Tnh ton cp phi b tngB tng M200+ Mc ch: Xc nh thnh phn cp phi cho 1m3 b tng theo mc thit k ph hp vi iu kin ct, ti hin trng m bo 2 yu cu: K thut v kinh t.+Vi b tng c M200 phi tnh ton cp phi.+ Tnh ton: Theo TCN D6-78 hoc 14TCN59-2002.Xc nh st ca b tng (Sn)+ st ca b tng ph thuc vo loi kt cu, iu kin thi cng: D nh ta s dng vn chuyn b tng bng cn trc, theo 14TCN59 (mc 4.1.5 th st hn hp b tng vn chuyn bng my bm b tng th st th ty theo yu cu tng b phn cng trinh, nhng phi Sn>10cm. Vy ta ly st ca hn hp b tng Sn = 14cm.Chn t l N/X:+ Chn t l cn c vo yu cu v cng Ta s dng cng thc tnh trc tip p dng cng thc : Rb28 = k.Rx.( - 0,5) Trong : Rb28 = 200KG/cm2 Rx = 400 KG/cm2 K l h s thc nghim K = 0,55 khi s dng dm Thay vo cng thc c c = 1,404 hay t l =0,7 - Yu cu v bn ca cng trnh thu cng: V y l cng trnh thu cng lun nm di nc chu p lc nn chn c t l = 0,7 tho mn v cng v bn ta chn = 0,7+ Tng t, tnh ton vi b tng li trn M150 vi Rb28 = 150kG/cm2, ta cng xc nh c X/N = 1,18Xc nh liu lng pha trnXc nh lng nc cho 1m3 b tng:Theo nh mc 1776 th lng nc s dng cho 1m3 b tng M150 v M200 l 186 (Lt)Xc nh lng xi mng cho 1m3 b tng .S dng cng thc: (kg)Suy ra XM200 = 186.1,404 = 261,144 kgV XM150 = 186.1,18 = 219,48 KgXc nh lng , ct cho 1m3 b tng+ p dng phng php tng th tch tuyt i cho 1m3 b tng:Vac + Vad + Vax + N = 1000 ltTrong Vac ,Vad ,Vax v N l th tch tuyt i ca ct, , xi mng trong 1m3 b tng m bo nh vy, th C, , N phi lp y l rng trong khe ca ct liu th, tc l:

Trong : K =1,25 l h s d va ( vi BT thng)N = ; rng ca + Cc thng s dung trng trong cng thc ly theo Bang 3 Cc ch tiu ct, , xi mngVt liu m%Dung trng ring a (T/m3)Dung trng t nhin kh o (T/m3)

Xi mng (P)03.11.25

Ct32.651.45

12.701.55

+ Xc nh lng cho 1m3 b tng:

Suy ra lng ct ca BT M200 v M150 c tnh theo cng thc sau:

0. iu chnh cp phi theo m t nhin ca ct v :+ Trong thc t khi thi cng, ct, c m, nn lng ct s thay i, coi Xi mng l kh hon ton, nh vy ta c cBT M200: Xtt = X = 261,144 kgNtt = N ( C.c + .) =186 - 30,78 =155,22 Ltt = .(1+) =1400,72.(1+0,01) = 1414,72 KgCtt = C.(1+ c) = 559,08.( 1+ 0,03) = 575,85 Kg

BT M150: Xtt = X = 219,48 kgNtt = N ( C.c + .) =186 - 31,85 =154,15 Ltt = .(1+) =1400,72.(1+0,01) = 1414,72 KgCtt = C.(1+ c) = 594,7.( 1+ 0,03) = 612,54 KgVy t l pha trn ng vi BT M200 l:X : C : : N = 261,144 : 575,85 : 1414,72 :155.22 TL l 1 : 2,2 : 5,4 : 0,59T l vi BT M 150: X : C : : N = 219,48 : 612,54 : 1414,72 : 154,15 TL l 1 : 2,79 : 6,4 : 0,7Tnh ton chn my trnChn loi my trn:Vic chn loi my trn phi da trn cc cn c:ng knh max ca ct liu Dmax = 40mmCng b tng thit k M200iu kin cung cp thit b y La chn loi my trn:Ta chn loi my trn tun hon ri t do, loi qu l m hiu SB15(S333G) c cc thng s c bn nh sau:Di 2,26 m, Rng 2,18m, cao 1,92mCng sut thit k 3KWDn ng nghing thng: Thy lcTc quay ca thng 18,2 vng/phtTh tch xut liu 330 LTh tch thng trn: 500LGc nghing khi np l 0Gc nghing khi l 52oNng sut trn l 8m3/hng c nng gu np liu: A0232-4Xc nh nng sut thc t ca my trn:Nng sut thc t ca my trn tnh theo cng thc:

Trong :Ntt Nng sut thc t ca my trn (m3/h);Vtt Th tch thc t vt liu vo my trn (lt)f H s xut liu = 0,65 0,7 => Chn f = 0,66KB H s li dng thi gian: KB = 0,850,95 => Chn KB= 0,9t1 Thi gian trn b tng: t1 = 60s.t2 Thi gian vt liu vo: t2 = 40s.t3 Thi gian trt va b tng ra: t3 = 30s.t4 Thi gian gin cch: t4 = 15s.+ Ta c th tch ca vt liu cn pha trn ng vi 1 bao xi mng 50Kg l:

S bao xi mng cho 1 ci trn: x = Vct/V1 = 500/340 = 1,47 baoChn s bao l 1 bao xi mng, vy th tch thng trn ng vi 1 bao xi mng l 340 (L). Vy t l Vct/Vtt = 330/340 = 0,97 = 9,7%Vy my trn ta s b chn hp l.+ Tnh nng sut thc t my trn:

Ntt = 5,014 m3/h+ Vi cng BT thit k l 124 m3/ca = 15,5 m3/hVy ta b tr trm trn gm 3 my trn.Ta c Ntram = 5,014.3 = 15,042 m3/hB tr mt bng trm trnB tr trm trn.Chn v tr t v cch b tr trm trn da trn nguyn tc:- Thun li cho vic tp kt vt liu, cung cp nc trn b tng;- Thun li cho vic vn chuyn ct liu, vn chuyn va b tng;- Hn ch vic di chuyn trm trn nhiu ln.Tnh ton vn chuyn ct liu- Nng sut ca mt xe ci tin khi ch ct liu l :

Trong : t1 Thi gian np ct liu vo thng xe: t1 =30(s).t2, t3 Thi gin i v v ca xe: v Vn tc trung bnh ca xe: v = 5 (Km/h)L Qung ng vn chuyn ct liu : L = 50mVy t2 + t3 = 72st4 Thi gian ct liu: chn t4 = 10s.t5 Thi gian tr ngi: t5=180s.Vxe Th tch thng xe: V = 200(lt) = 0,2 (m3) trnh ri vi va b tngKb = 0,9 H s li dng thi gian

- S xe ci tin cn c vn chuyn ct liu l :

=> chn 2 xe ci tin vn chuyn ct liu v 1 xe d tr khi c s c.Tnh ton s xe vn chuyn va b tngYu cu ca vn chuyn va b tng.+ B tng khng b phn tng phn c. Mun vy ng vn chuyn b tng phi bng phng gim s ln bc d khng b tng ri t do t trn cao xung khi cao b tng ln hn 2,53 m th phi c phu, vi voi hoc mng .+ m bo cp phi ca va b tng ng yu cu thit k, thit b ng b tng khng b r r , khi ch b tng khng nn ch qu y trnh va b tng b ri vi , ch che y khi tri nng, ma+ Khng b tng sinh ra ninh kt ban u, thi gian vn chuyn va b tng khng c vt qu thi gian cho php, cn s dng phng php vn chuyn tt rt gn thi gian vn chuyn.+ Vic vn chuyn va b tng n khonh cn m bo tc b tng, trnh sinh khe lnh khonh . xut v la chn phng n vn chuyn va b tng xut phng n vn chuyn:- PA 1: Dng t kt hp vi bm b tng a va b tng vo khonh - PA 2: Dng xe ci tin vn chuyn va b tng vo khonh (c ly khng gy nt do ng sut nhit;- Mt b tng nm ngang phi ph ct hoc mn ca ri ti, cng vi trng c, xy gch v bm nc vo;- Mt b tng ng (nh tng) phi ti phun lin tc - Thi gian dng h: khi mt b tng xe li, khi phun nc vo b tng khng b xi th bt u dng h.*Khi dng h b tng Ta dng cch sau:- Ph ln b mt b tng mt lp ct ti m nn ct gip cho b tng m pht trin cng .- Ti ln b tng: khi b tng m thi tit nng qu th ngi ta thng tin hnh b tng vo ban m nh nng khng nh hng n s pht trin cng b tng.- S pht trin cng b tng ban u rt quan trng, nu b nh hng ngay thi k u th lc b tng khng cng rt d sinh ra nt, mt nc nhanh qu xi mng khng thu ho kp.Kim tra kh nng pht sinh khe lnh i vi khonh in hnhTa kim tra i vi hai phng php ln u v lp nghing. iu kin khng pht sinh khe lnh khng pht sinh khe lnh th khonh phi tha mn iu kin sau:

Trong : [F] Din tch khng ch b tng khng pht sinh khe lnh k H s do b tng khng u: k = 0,8 0,9 => chn k = 0,9 N Nng sut thc t ca trm trn: N = 15,042(m3/h) T1 Thi gian ninh kt ban u ca xi mng, ph thuc vo loi xi mng v nhit mi trng ti thi im b tng: T1=1,452(h) => chn T1=1,5h. T2 Thi gian vn chuyn va b tng t trm trn ti khonh :

h Chiu dy mt lp , ph thuc vo bn knh tc dng m:h = 0,8Ro = 0,835 = 28 (cm)

Kim tra iu kin khng pht sinh khe lnhKim tra cho bn y (phng php lp nghing)Ta chn bn y dc nc 1(khonh 34) lm khonh in hnh v n c khi lng ln v c chiu rng ln nht. Vi phn chn ca bn y ta ln u, pha trn ta s lp nghing nh hnh v:

Hinh 2 Phng php lp nghing Vy bn y khi theo phng php lp nghing khng pht sinh khe lnh.Kim tra cho li trn (phng php ln u)Ta chn khonh 15 v 16 ca li trn lm khonh in hnh kim tra, do n c chiu cao ln, v chiu B tng i ln, vi phng php ln u, chiu cao mi lp l 28cm

Hinh 3 Phng php ln uF=B10=57(m2)=> F = 57 (m2) < [F] = 71.31 (m2)Vy khonh m bo khng pht sinh khe lnh theo yu cu.Thit k vn khun, cch lp dng vn khun cho khonh in hnhTa chn vn khun lp dng b tng l vn khun thp v c gia cng hng lot ti xng. Vn khun c ch to theo kch thc ca cng trinh cho mt s ln lun chuyn nhiu nht v khi lp phi phn ln va vi kch thc ca cng trnh.Trong n ny ta chn vn khun lm bng thp c kch thc: 2503000,5cm. Cc loi ti trng+ Trng hp chu ti trng:Vn khun ng: Chu tc dng ca cc lc nm ngang.Vn khun nm: Chu tc dng ca cc lc thng ng. y ta tnh ton vn khun cho khonh in hnh l khonh tng ca trn, nn ta ch tnh ton vi trng hp vn khun ng.p lc ngang ca hn hp b tngq1 = bt R0 = 2400 0,35 = 840 (kg/m2)Trong : bt Trng lng ring ca b tng: bt =2,4 (T/m3) = 2400(kg/m3) R0 Bn knh tc dng ca m: R0 = 35 (cm) = 0,35 (m)Ti trng ng pht sinh khi hn hp b tngTheo bng 3.2 (14TCN 59-2002) ti trng ng pht sinh khi b tng, vi phng thc b tng t vi, ng ca bm b tng => q2 = 200 (kG/m2)Ti trng do chn ng ca m b tngTheo (14TCN 59-2002 mc 3.1.1.4) ti trng do chn ng ca m b tng i vi vn khun ng q3 = 200 (kg/m2)Tng hp ti trng tc dng ln vn khun tng ngTi trng tnh ton: qtc = q1 + q3 = 840 + 200 = 1040 (Kg/m2)Ti trng tiu chun:

Trong : ni H s vt ti trng ( theo tiu chun ti trng v tc ng) + n1 H s vt ti ca p lc ngang ca hn hp b tng: n1 = 1,3. + n3 H s vt ti ca ti trng do chn ng ca m b tng: n2=1,3.=> qtt = 1,3. 1040 = 1352 (kg/m2)Thit k vn khunThit k vn mt+ S b ta b tr 2 dm chnh v 3 dm ph nh hnh v

Hinh 4 S b b b tr dm vn khun+ Ta c s tnh vn mt nh sau:

Hinh 5 S tnh vn mtLc tc dng ln vn mt l lc phn b u, coi vn mt nh dm lin tc ta trn cc dm ng v ngang.Lc tc dng ln vn mt l:qvm = qttaTrong : b B rng tm vn, ly b rng n v tm vn a =0,75(m)=> qvm = 13520,75 = 1014 (kg/m)Mmen ln nht tc dng ln bn mt:Mmax = ql2/8 = 1014. 0,752/8 = 71,297 (daN.m)Trong : l Khong cch gia cc dm l = a = 0,75 mTheo iu kin v cng Vi vt liu lm vn khun l thp, ta c Suy ra Trong :W = b.h2/6Vi h = t = chiu dy tm mt; b = a = 0,75 mVy ta c:

Vy chn chiu dy tm mt l 0,5 cm Kim tra khong cch gia cc dm chnh thng qua s tnh ton dm ph:

Xc nh khong cch cc dm chnh + Theo iu kin v cng :

Trong : [] - ng sut chy cho php ca thp: = 2800(kg/cm2) qvm Ti trng tc dng ln vn mt: qvm = 1014 (kg/m) = 10,14(kg/cm)+ S dng thp nh hnh lm dm chnh, s dng 2 thp [ 14 c W- m un chng un ca vt liu lm dm Wx = 70,2 . 2 =140,4 (cm3)Suy ra L < 622,64 cm+ Theo iu kin v vng:

Trong : +E M dum n hi ca thp: E = 240000 (kg/cm2)

+ [f] vng cho php: =0,0025+ qtc Ti trng tiu chun tc dng ln vn mt: qtc =10,14 (kg/cm)+ J - M men qun tnh chnh trung tm ca dm: Jx = 2.491 = 982(cm4)L < 195,19 cmT (1) v (2) m bo v cng v vng ta chn khong cch gia cc dm chnh l1n = 100 (cm) = 1(m).+Tnh khong cch gia cc dm ph theo s tnh

+ Theo iu kin v cng :

Trong : + l khong cch gia cc dm vn+ [] - ng sut chy cho php ca thp: = 2800(kg/cm2)+ qvm Ti trng tc dng ln vn mt: qvm = 10,140(kg/cm) + W- m un chng un ca vt liu lm dm Wx = 70,2 (cm3)Suy ra: L < 440 cm+ Theo iu kin v vng:

Trong : +E M dum n hi ca thp: E = 240000 (kg/cm2)

+ [f] vng cho php: =0,0025+ qtc Ti trng tiu chun tc dng ln vn mt: qtc =10,14 (kg/cm)+ J M men qun tnh chnh trung tm ca dm: Jx = 491 (cm4)Suy ra: Ldphu < 154,9cmT (1) v (2) m bo v cng v vng ta chn khong cch gia cc dm ph l1n = 75 (cm) = 0,75(m).Tho d vn khun v lp dng vn khun:Lp dng vn khunDo y l vn khung ng nn ta tin hnh lp t trong ra ngoi v t di ln trn. * Cc bc lp dng nh sau: 1- a vn khun vo v tr c bu lng t chnh xc t trc, dng vn khun. 2- Bt bu lng gia cc bin vn khun vi nhau (v c th bt thm 2 hoc 3 ci bu lng phn bn trong gia 2 vn khun tng vng chc gia cc vn khun) v gia vn khun vi b tng ca t trc. 3- Bt bu lng v t thanh thp chng khng ch (nu c). 4- iu chnh 2 tng vn khun va dng cho chnh xc v kch thc v thng ng bng trc t (qu di phi t trong nc hoc du trnh nh hng ca gi ). 5- Chng bng ct g, hoc ct st vi khi di thp (t i) hoc ging c tng iu khin. mi tm vn khun phi c 1 ging nghing 1 gc 30- 450 6- Kim tra li kch thc v ng 1 ln na trc khi .Tho d vn khun : Thi gian tho d vn khun phi cn c vo c im kt cu, iu kin kh hu, tnh cht ca b tng Ni chung cng tc tho d vn khun phi tha mn cc iu 14TCN 2002 . Trong chng ta cn ch cc vn c bn nh sau:Phi cho b tng t cng mi tin hnh tho d. Khi nhit mi trng thi cng trung bnh 270C, dng xi mng PC40 th thi gian ti thiu b tng t cng m chng ta c th tho d vn khun ng l 1,5 ngyQu trnh tho d vn khun: vn khun ng th tin hnh tho d t ngoi vo trong.9. Kt lunTrn y l ni dung n Cng ngh xy dng v cng trnh b tng gip em hc hi c nhiu iu b ch nh bit cch s dng mt bn v bc tch khi lng v gip em cng c kin thc hc c trn lp. Nhng trong qu trnh lm n em khng th trnh c nhng thiu st trong khu thuyt minh tnh ton. Em mong thy nhn xt v ch bo thm cho em. Cui cng cho em c by t lng bit n chn thnh n cc thy gio, c gio v c bit l thy Mai Lm Tun gip em hon thnh n ny. Em xin chn thnh cm n!