KHOA HOC CONG NGHE & CUOC SONG
NANG VAT NANG DONG HANH CUNG THJ CONG COP PHA TRl/OT
Le Anh Dung Ha Quang Hiftig
ABSTRACT
In construction projects, high-rise rein- forced concrete (RC) work items having heavy structure on top are executed in tw^o
phases: pouring concrete first by slipform then erecting heavy structure by crane or by-hand. In this case, lifting heavy structure and sliding formwork simultane- ously is a new efficient method to solve the
problem. This paper descripts the method statement and points out some notes in practice.
TSLe Anh Dung Van phong Bo Xay dung KS Ha Quang Hung Trudng Dai hoc Kien true Ha Noi KM10, Nguyin Trai, Thanh Xuan, HaNoi
I. DAT VAN BE
Bien phap thi cdng nang vat nang (thudng la he dam hoac dan mai cua cac cdng trinh cao) eung vdi he mam san trong qua trinh thi cdng be tdng bang cdp pha trUpt la bien phap thi cdng tien tie'n, hien dai. Trong trudng hpp ket cau ldn, nang; dUpe lap dung d dp cao ldn, nam ngoai kha nang edng tac cua eae loai can true hoae khdng ed dieu kien sU dung can true cd sQc nang ldn, tam vdi eao. Khi do bien phap thi cdng nang vat nang ddng hanh cung he cdp pha trupt la bien phap kha thi nhat, vUa giai quyet dupc yeu td ky thuat vQa day nhanh tie'n dp va hieu qua kinh te.
II. MOTA PHl/ONG PHAP 1. Md ta phUorng phap thi cong cop pha trUot
Thi cdng bang van khudn trUcrt la mdt bien phap thi cdng trlnh dp ed gidi hoa cao, td chQe thi edng nghiem ngat, toe dp nhanh va ed hieu qua nhU cdng trinh betdng do tai chd. Hien nay cdng nghe thi cdng cdp pha trUcrt sQ dung kich thuy lUe la phd bie'n nha't. Nd thdng qua tram bom dau, lpi dung mdi quan he tuong hd cua he thdng van khudn - ty kich (thanh try kich) va betdng mdi do khien cho toan bd kich dem van khudn, san thao tac, tai trpng thi cdng tren san eung djeh chuyen len cao dpc theo ty kich.
2. JVI6 ta phuong phap nang vat nang dong hanh cung cop pha truot
PhUPng phap nang vat nang ddng hanh cung thi cdng cdp pha trUpt chinh la sQ dung he thdng mam san cdp pha trUpt de mang vat nang (d day thudng la cac dang ket eau dam - dan thep hoae betdng cdt thep) tdi dp cao can thiet sau dd lap dung vao vj tri thie't ke. Nd khdng ehl rut ngan thdi gian thi cdng, tang hieu qua ve mat kinh te ma cdn han che cac rui ro mat an toan do lap dung tren eao.
Thi cdng nang dan mai silo ddng hanh cung cdp pha trUpt
Ve quy trinh, sau khi lap dUng va can chinh xong he thdng mam san trupt, tie'n hanh lap dUng he dam - dan mai bang each td hpp tUng phan tQ nhd bang thu cdng hoac can true.
He dam - dan dUpe td hpp dung nhu thie't ke tren mat bang ve tim - true eua ket eau. Cd the td hpp khdng he't eae phan tQ cua he dam - dan (de giam thieu tai trpng tae dung len he mam san) nhUng phai dam bao he nay cQng vQng, chju dQpc tai trpng ban than va khdng bie'n hinh trong thdi gian nang trQpt. He dam - dan luc nay nam tren he chdng dd tam, ed the la giao hoae cae tru dd chju iQc dQpc tinh toan dam bao kha nang chju iQc.
Vdi trQdng hpp cae vat nang dupe nang trUpt tQ cdt mat mdng (d day hieu la ty kich chdng trQc tie'p len mat mdng) thi chi dQpc lien ke't he dam - dan nay vao mam san sau khi be tdng da ra khdi cdp pha tQ 50em - 70em de tranh sQ mat on djnh cua ty kich do be tdng ehUa du eudng dp.
g K r a i i l g i l . 12.2009 51
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Thi cdng nang dan mai silo ddng hanh cimg cop pha trifpt
Lien ket gida dam cong trinh va dam ganh + khung kich Ghi chu: i'l ^ 1 -Dam (Gia) Dd dam ganh
2 - Khung kich 3 - Gia dd kich 4-Vitme(t)32 5-Oemgidvitme 6-Thanh treo dam mai 7-Dam mai can nang 8 - Dam ganh (02 cai)
i i'^1'
'^"^•Sii
iii,^". ,!<i \ l
Chi tiet lien ket dam mai - khung da tru'pt
Trong trQdng hpp ty kich da dQpc ngam vao be tdng tQtrQdc giai doan nang vat nang, de dam bao sQ dn djnh cua ty kich thi eung chi nen lien ket he dam - dan nay vao mam san sau khi be tdng da ra khdi cdp pha tQ 20em - 30cm. Bien phap nay thQdng dQpc ap dung trong thi edng cdp pha trUpt cac ke't cau ed chieu day tie't dien thay doi. Khi dd, vat nang se 6\Jac nang eung cdp pha d eao dp thay ddi tie't dien.
Trong qua trinh nang vat nang ddng hanh eung cdp pha trQpt, edng tac trac dae dp nghieng - xoay eua mam san phai het sQc coi trpng (tQ 15 - 20 bQde nang kich thi quan trac 1 lan) va sQdung ke't hpp nhieu bien phap can chinh de dam bao yeu eau 2 kich lien ke khdng chenh lech eao dp qua 2cm, eae kich bat ky khdng qua 4cm. Tuyet ddi khdng dupe sQ dung bien phap chenh lech eao dp giQa cac td kich de dieu ehinh nghieng mam san.
Sau khi trQpt nang vat nang den dp cao tinh toan, thQdng la eao hdn cdt thiet ke 10cm -15cm, tien hanh ha vat nang vao vj tri. TrQdc khi tach vat nang khdi mam san, can phai tinh toan dam bao gdi tQa dd vat nang dam bao kha nang chju iQc cue bd tai tie'p diem. Vdi cac loai dam - dan mai bang thep thi cdt dinh dQng trQpt cung la cdt dQng de ha vat nang. Thdng thQdng cd the tie'n hanh ha vat nang sau 2 - 3 ngay ke tQ khi dQng trQpt.
III.VANDETI'NHTOANVALIEN KET 1. Tinh toan, lUa chon, bo tri kich - Ve nguyen tac, nen bd tri chia deu tai trpng cua vat nang vao eae diem dat theo chu vi mam san.
- Ngoai sd iQpng kich - ty kich da dQpc tinh toan de chju tai trpng cua he mam san, tai eae diem dat phai tinh toan them sd iQpng kich de chju tai trpng cua vat nang. Sd iQpng kich - ty kich cd the tinh toan theo Phu luc 3 - TCXD 254:2001. He sd an toan cua kich k>2 (vi du dung kich 6 tan thi chi nen tinh kha nang lam viec cua kich la 3 tan).
- Nen sU dung kich 4,5 tan hoae 6 52^l9ni[15il . 12.2009
Giang cheo lien ket khung tai diem gdi
Ghi chu:
1. Khung kich do dam can nang
2. Khung kich ke ben khung kich dd dam can nang 3. Giang lien ket
4. Vanh cudn
tan, khdng nen sQdung loai nhd hpn.
- Bd tri: trong trudng hpp tai trpng dat tai cac diem tQOng ddi Idn, lap dat kich kep van chQa du kha nang chju tai thi ed the lien ke't cae khung lan can eung chju tai.
2. Chi tiet lien l<et vat nang - mam san
- Tuy thupc vao chieu eao tinh toan cua ke't eau can nang ma cd the cd gia chju iQe chQ A, hoae chQ nhat dat tren dinh 2 khung da trUpt canh nhau. Ndi 2 khung dQng chju iQc nay la 1 dam ganh thep hinh. Treo dau dam - dan vao dam ganh bang vitme chju iQc.
- Sd iQpng vitme, dQdng kinh, cap thep... tinh toan theo so do eau kien chju keo dung tam.
- Chieu dai vitme chju lUc dupe tinh toan dam bao du dp dai de ha dam vao vj tri thie't ke tren dinh.
- Trong trQdng hpp dam (1) dd dam ganh khdng du chieu eao thi thay the bang gia chju iQc chQ A hole chQ nhat nhQ hinh ben.
- Tranh viee treo he dam - dan qua eao gay nen hien tupng dao ddng (nhu qua lac) anh hUdng de'n sU dn djnh cua mam san. NgUpc lai viec treo he dam qua tha'p se khie'n khdng gian tren san thao tac chat hep, lam giam nang suat lao ddng cua cac day ehuyen thi edng khac.
- Dam bao cdt treo eua tat ea cac dau dam - dan la nhu nhau tranh hien tUpng eao tha'p lam lech mam san rat nguy hiem.
- Lien ke't giQa dam (gia) dd (1) va gia dd kich (3) cd the dung lien ket han nhUng tdt nhat la dung lien ket buldng. Lien ket giQa (1) va dam ganh (8) dung lien ket han tai edng trudng.
3. Gia cUcrng he mam san trUOt - Ngoai viec han giang cheo giQa eae vanh cudn d dUdi san thao tae thi tuy trUdng hpp ed the bd tri them mdt lUpt giang nQa tren dinh eua khung kich de tang sU on djnh, hd trp lan nhau cua cac khung kich nay.
IV. KET LUAN
Bien phap thi edng nang vat nang ddng hanh cung cop pha trQpt la bien phap thi cdng tien tien, hien dai. Bien phap nay dem den eho nha thau xay dQng them mdt cdng eu giai quye't cac van de thi cdng lap dung tren cao, nd khdng ehi giup nha thau rut ngan thdi gian thi edng, hieu qua ve mat kinh te ma cdn han ehe cae rui ro mat an toan do lap dQng tren cao.
Mac du cd nhieu Uu diem nhU vay nhung cdng tae thiet ke, tinh toan...
kha don gian; khdi lUpng phat sinh phuc vu bien phap nhd.
Tuy nhien, trong qua trinh thi cdng thUe te, viec dam bao mam san trUcft len deu va dn djnh rat phQc tap. Nd ddi hdi ngQdi can bd ehi huy thi edng phai dupe dao tao bai ban, nam vQng cdng nghe cdp pha trQpt va ed kinh nghiem khi dieu chinh mam san; ngUdi edng nhan phai tuyet ddi tuan thu bien phap thi cdng, an toan da dUoc hpe. •
BiignffiilBil . 12.2009 53
