DIEN DAN KHOA HOC CONG NGHE

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P G S. T S. NGUYEN BAO HUAN - C DC

Y t u d ng t h i lt k l: Canh quan sa mac Rub Al Khali ket n il vdi cang bien vung vjnh Per sic tupng trung cho sdc s i ng va p h in vinh thjnh vupng cua Tieu vuong quic Dubai. KTS Adrian Smith cam nhan ring dinh ciia toa nha Dubai thilt kl da cao d in tpt dinh mpt each "thanh nha & duyen dang" td day cd the nhin toan canh dudng chan trdi nhpn nhjp. Hoa sa mac la nguIn cam hung cho y tudng xay dyng thap Dubai, lam thay doi dudng v i in trung tam mdi Dubai. K it c lu ngoai hinh kiln true cd tinh on djnh dl k it hpp cac anh hudng van hda, Ijch sd truyin t h i ng ban dja va t i lp thu kiln true hien dai Phuang Tay.

Hinhl: Toa thap nhff mot cay kim

Cac tda nha mai vom va chdp nhpn, kiln true H6i giao kieu x o ln Ic vdi c lu true loi trung tam bung ra xung quanh ba canh hoa la y tudng kiln true nha d tao dyng mat bdng hinh hpc ba true. Thap vdi hinh khii xoay Ic nhpn dan theo chilu cao, thap nhu mgt cay kim duac mieu ta la "thanh phd thang dung" bdi no lam lu md mgi toa cao 6c hien co va day lui mgi gidl han Kiin True & Xay Dung.

Vdc dang canh hoa xoe nhj hoa vut cao la bieu trung ciia Thap n il tilp khdng gian kiln true luon nhin t h iy canh mat trdi moc va lan, Thap tao ra moi trudng d, nghi ngoi va giai tri vui choi dl chju vdi mdi trudng sing nhilu anh sang ty nhien, g in k it gilc mo "decugc sdng va cdng tac cua ngudi dan tdt dep han"

Taipei Ddi B ad 01 tang 2. Dinh mdi nhd 643,3m; trudc ddy nhd Taipei 101 Ddi B IC 449,2m 3. Oinh k it c lu sdn nhd 624,1 m; trudc ddy Taipei Djnh nghTa "nhd cao nhat th§ g i d i" Ngay td ddu, ngudi ta d in ring ring thdp Burj Dubai khdng chl Id k i ln true cao nhlt cua t hi gidi, md Id vdt the nhan tao duyen ddng dpc ddo ddng ty do giura sa mac cdc t i iu vuong q u ic A Rap. Ddi Bde 509,2m 4. Bom betdng t h i ng ddng 643,3m - ky luc trudc ldp day Taipei 439,2m 5. Oinh chdp Anten: 828m - Thdp Sears Chicago- My cao 527m c lu true dimg ty do: CN Toronto Tower Canada Hpi d i ng Nhd cao t i ng vd C hl d do thj (CTBUH), tai dai hpc Lehigh d Bethlehem, thanh Pennsylvania, cd tru sdtai vien Illinois, Chicago (My). Chu tjch, ong AntonyWood cong bl cdc chilu cao ky luc qua b in tieu chuan cho thap Burj Dubai (tfnh td via hd cira vao chinh) sau: cao 553m 1. Nhilu tdng nhlt: 162 t i n g, trudc day Tod nhd

Mac dii chilu cao c u li cung ciia thdp Dubai ngdy hdm nay mdi Ip dien, nhung thdp da dat phdn Idn sl tieu chuan ddng ke trong t it cd cdc chilu cao nhlt cua Ban gidm khdo Hpi ddng trpng tdi CTBUH nhu trdn.

Hinh 2: Maf bang kien true dien hinh khaeh san

lUlo td K it c lu Mat bdng k i ln true thdp Dubai dang T" x o ln Ic cd Idi cung len cao d in ngpn thdp (Hinh 3) Id y tudng cua cong trinh su Bill Baker - SOM: nhdm gidm tdi trpng gid va dap len thap, cOng nhu gid cho c lu true bdtdng don gidn, kiln true b in virng dn djnh (con- structability). Mat bdng ba cdnh (wing) thdp "Y" cd mpt chuli cpt mui ddu h ii ndm tren sdn t i ng cung, nhimg tudng ddi ngan khong gian kiln true ba nhdnh thdnh hdnh lang d iu dupc lidn k it vdo Idi luc gidc gida tod thdp nhdm ching x o ln hidu qud (torsionally) cho cdng trinh. Vdn phdng K i ln true SOM dp dung quy ludt hinh

NGUdi XAY DI/NG S6 THANG 6-2011

P H AN T I CH KET C AU & T H I ET KE...

Hinh 3: Thap dang thi cong

san cirng thu hep md khong gap trd ngai lien quan thudng xuyen d in ehuyen ddi vj trf cac cpt tang tren. Nhdng khoang lui thu hep bl rpng t i ng cimg nhu yay lam thay ddi bl rpng cua mdi cdnh thap qua mdi ting cdng. Theo SOM mpt sdng tao ciia ky su k it e lu la gib xoay khdng bao gid hinh thanh dupc tren kiln true thap. Ky su Bill Baker ndi: "Ket cau phai kit hgp cung vdi kiin true va thiit ki ben vdng khdng the tach rdi".

Phan ti'ch t h i lt kl & k it cdu Cac vach cdng chju cat ciia loi betdng hinh luc giac cd dp ddy tU 1300 mm gidm d in 500 mm cung cac lanh td cira cao td 800 mm d in 1100 mm hinh thanh mpt k it e lu tdm cdng khdng x o ln tuong ty lang tru liln xung quanh thanh mpt k h i i. Cac tudng trung tam thap bl trf thanh hinh luc gidc lai dupc gia cudng bdi tudng hdnh lang va cpt d d iu hdi cde canh tao thanh nhu mang ludi vd cac con son sdn dam gian hdng cdng ngang de c h i ng e lt vd moment do gib. D im gian hdng (outrigger) betdng liln k h ii ndm tren cac san tdng mechanic cho phep thay ddi nhip cot dpc lap rpng hon tai cac tdng dudi, len t i ng tren thu hep tham gia vdo chiu lyc, tang kha nang ching dotal trpng ngang truyin vdo Idi thap luc gidc, vi vay tit ca cac k it c lu dung d iu tham gia hi trp ehing dd ca tai trpng dung (lyc trpng trudng) vd tdi trpng ngang. V4 cudng dp betdng: mac cao thudng hiem nen kich thudc k it c lu sdn Idn, tai trpng ban than nang truyin len Idi cimg vd cac cpt bien. Betdng Mdc cao cung d i ng nghTa sddung vat lieu ft hon, gidm thieu dang ke td biln bdng each tang ty trpng vd Idm tU biln cham lai. Cf day sd dung xi mang Portland vdi M800 (C60) d in Ml 000 (C80) cho tudng betdng ehju elt. Thilt kl sd dung c lp p h li be tong tai chd.

hpc kiln true d li xirng tuyet d li de t it ca cdc p h in td cpt tru betdng va mang vach ciia cac canh thap dupc lien k it tieu chuan qua loi trung tam.

Hinh 5: Mo hinh mat bang phan tich

Hinh 4: Loi effng luc giac gdm cac tffdng chju cit

NGUdi XAY DUNG SO THANG 6 • 2011

Cu the c lp dp b in C80 (cudng dp chiu nen cua betdng cdn thilt phdi dl cap d in cudng dp sau 48 ngdy vl cdng trinh chiu tai trpng dpng vl sau) dat gi^ tri quy djnh Md-dun dan hdi E = 43.800N/mm' (6350ksi) cho tudng betdng d t i ng thdp hon. Sir dung kfch thudc t li uu cho trudng vd cpt lam viec theo cong nang/phuong phap c lp sl nhan Lagrange r it hieu qua (Baker et al.2000). T h i lt kl k it edu be tdng pliu hpp yeu c lu Tieu chuan ACI 318-02. Cac canh thap len cao thu hep d in tao thanh nam (5) bac san co hpc (tiers), m il bac cd nhilu san k it c lu dien hinh thilt kl lap lai theo mpt md hinh xoan Ic nhdm day nhanh t ic dp xay dyng. Thap cdng len cao cang nhpn d in gay trd ngai to chdc so dl truyin tai trpng dimg, nhu vay cac cpt m il tdng tren ndn thing tya tren cac tudng t i ng phfa dudi tao dudng truyin tdi trpng lien tuc. D i lu nay cho phep xdy dyng m il bac

P H AN T I CH KET C AU & T H I ET KE...

tdi

Dp ddy tudng vd kfch thudc cpt dupc dieu chlnh de giam bdt nhumg dnh hudng td biln vd co ngdt betdng trong nhiJng clu kien dpc lap tao nen he kit clu. De giam td biln chenh lech do co ngdt betdng giua cdc cpt tren chu vi vd cdc tudng phid trong, kfch thudc cdc cpt dupc tli uu de ung suit trpng lupng trpng trudng gay ra tren cpt ngang bdng vdi img suit tren cdc bUc tudng hdnh lang ben trong mil canh.

Dang dao dong 1

Dana dao dong 2

Nam (5) sdn chuyen ting (sdn dat outrigger nhu dim gian hdng cdng) se phdn phli lai tdi trpng tod nhd, lien kit (tie) tit cd cdc clu kien thing ddng cung chju tdi trpng, hon nda bdo ddm Ung suit trpng trudng phan bl diu, vl vdy giam chenh lech chuyen djch khdc nhau do be tdng co ngdt. Ndi chung dli vdi cpt hodc tudng mdng thi td biln betdng xay ra nhanh hon, CO ngin kfch thude kit clu do dd thilt kl chpn dp ddy tilt dien cpt cdn 600mm (24") se phu hpp ciing ty le vdi tudng hdnh lang (ty le tuong ty td the tfch din bl mat).

D<7ng dao dong xoan

dien md hinh 3D gdm hon 73.500 phin td shells vd 75.000 phin td nut. Dudi tac tdi dpng trpng gid, thap bj chuyen djch ngang A ndi Chung id binh thudng: ngudi lam viec t r 0 n g V d n phdng ting cao elt nhlt + 6 0 4 , 9 m [chuyen djch ngang A = 1 2 5 0 m m] ngudi d trong ting can hp cao nhdt + 3 7 5 , 3 m [chuyen djch ngang A = 540mm]. Phan

Hinh 7: Cac dang mo hinh dgng

1

tfch cdc dang dao dpng cd chuyen dich ngang vl mpt phfa vdi chu ky T =11,3 giay (H.7a). Dang dao dpng thU hai cd chuyen djch ngang phuong vudng gde vdi mat thap cd chu ky T = 10,2 gidy (H.7b). Xoln Id dang dao dpng thd nam chu ky T=4,3giay (H. 7c)

Tieu chuan UBC97 quy djnh rd thdnh phi ty trj Dubai (DM) Id Khu vyc dja chin vung 2a (vdi dja chin vung Z= 0,15 vd dit nin loai Sc). Cdc phan tfch dja chin tucng umg phuong phap phd phdn umg ddn hdi. Tieu chuan thilt kl dpng ddt khdng dilu chlnh cho thilt kl kit clu betdng nha quay vd thap cd mdi chdp kit clu gidn thep.

Hinh 6: Ket ciu chju Iffc chinh toa thap

Tiln sy tu vin Max Irvine - Ky su cO hpc kit clu vd dpng lyc hpc cdng trinh- cd try sd dat tai Sydney - Australia - da bao do cu the vi mgi hiem hga tiem in mang tinh huy diet cua mdi trudng cho Du in. Nguy cd dat hoa long da duac dtiu tra ca ban dua tren phuang phap bao cao xac dinh hda long khdng cd bat ky tic dgng xau nao cho mdng sau cua Thip.

Thf nghiem 6ng thdi Gio: Dli vdi chilu cao vd dp mdnh ciia thdp Dubai thi dp lyc gid vd dao dpng cdng trinh d dp cao ddn din kit qud trdthanh ylu tl chii dao trong thilt kl kit clu. Chuong trinh nghien cdu md rpng thf nghiem thdi gid tunnel len tudng kfnh bao ehe xung quanh kiln true mat thdp do Tiln sy Peter Irwin chl dao thyc hidn d Guelph, Ontario

Mat cdt mdi thdp Id kit cdu he thanh thdp cheo ngang, chdp (spire erection) nhpn thing ddng dupc thiet kl chju tdi trpng trpng trudng, dp lyc gid dpng, lyc dpng dit vd dp bin mdi theo yeu clu ciia Tieu chuan tdi trpng cho thilt kl ddc biet dli vdi tod nha ket clu thdp -AiSC (1999). Cdc thep tilp xuc mdi trudng dupc boc nhdm de ching chdy. Kit cdu mdi chdp dupc phdn tfch bdng phin mim ETABS phien bdn 8.4 (bao gdm ca phdn tfch P-Delta) cho tdi trpng trpng trudng, luc gid vd tdi trpng dpng dit. Cac md hinh phan tfch ba chilu bao gdm cdc bUc tudng be tdng elt thep, cdc dim lien kit tdm sdn, bdn mdng bd, cpc khoan nhii, vd mdi chdp nhpn kit cdu thep. Cdc phdn tfch todn

Cdng ty Rowan Williams Davies & Inwin (RWDI thf nghiem Ing thdi gid bao gim nghien ciru cdc md hinh

NGUdi XAY DI/NG S6 THANG 6 • 2011

PHAN TJCH K JT C ^" ^ THIET KE.

Dubai, CTy RWDI cdn nghien cdu vdn dl thdng gid va an toan cho ngudi di bp tren cao, cd hieu qua (Inwin et al, 2006).

De xae djnh tai gid bdng thf nghiern thoi gid len chi'nh dupc thyc hien sdm trong cac thilt ke sddung ky thuat cao t in - ky thudt can b i ng lyc. Nhtmg sl lieu I ng gid thdi sau dd dupc k it hpp vdi cae tfnh chit dong hpc ciia thap de dap ung tfnh toan hieu qua tdng the phan trpng gid d ty le d ly dii. o li ydi thdp Burj Dubai k it qua eua cde thf nghiem can bdng lyc da dupc siJr dung nhu la d iu vao de thilt kl k it c lu vd hinh dang thdng sl de chi t i lt thap va eho phep nghien cdu thuc hieri tren nhdng anh hudng b i ln ddi phdn p h li khii

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Hinh 8: Kit ciu betdng cdt hep chju Iffc ciia thap phij hdp theo Yeu ciu Tieu chuan xay dffng ACI 318-02 ddi vdi kit cau betdng - (ACI,2002) -Vlen betdng My.

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Hinh 10a: Mo hinh tinh toan gid xoay

o w ss wmo n of •«»

lupng va dp cung thap. cdng - lyc can bang, nhilu md hinh khf dpng dan h ll d ly dil mdc dp ty do (aeroelastic), nghien cdu mdi trudng gid bao cho ngudi di bp tren t i ng cao, nghien cdu mdi trudng khf hau (Md hinh danh gia cac hieu ung gid ngang do gid xoay gay ra mpi tham hpa tiem an mang tfnh hiiy diet).

Toa nha cd sau hudng gid ehii dao quan trpng. Cac hudng gid chfnh la khi gid thoi vao "mui nhpn d iu hll" /"mui hung gid" ciia mdi canh trong ba canh (mui ddu hdi A, mui dau hdi B va mui d iu hdi C).

Cac nghien cdu ve lyc can bang va khf dpng dan hdi da sddung md hinh h lu h i t ti le 1:500.Tien sy Nick Isyumov chuyen gia ky thuat I ng thoi gid ciia Cty RWDI tai Oai hpc Western Ontario da thyc hien thf nghiem thoi gid vao Idp bao che xung quanh k i ln true thap. Ngoai cac thf nghiem chat tai ket cau thap Burj

Hinh 10: Gio thoi vao mui C dffdi thip & gio hut giffa 2 canh A&Bd

tren cao

Ba hudng khae khi gid thoi vao gida hai nhanh la gib hut, gpi la "mat hut gid" djnh hudng (mat hut gid A, B va C). Chli y rang hinh anh lye d li vdi cac hudng gid khao nhau cho t h iy sy kfch thfch trong dai t in suit ft quan

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Hinh 9; Mo hmh ong thoi khi dan hoi & gio dong

NGUdi XAY DI/NG S6 THANG 6 • 2011

PHAN T I CH KET C AU & T H I ET KE.

quan trpng d li vdi gid thdi va dap vdo mui nhpn d iu hdi culi ciJng hon Id td cdc hudng ngupc lai (mat hut gid). Dilu nay da khang djnh khi lya chpn hudng ciia thap so vdi cac hudng gid manh thudng xuyen nhdt cho Dubai vd hudng ngupc lai. thf nghiem can bdng

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Hinh 11: Bill Baker thi nghiem tunnel gio thoi va hut

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Hinh 13: Hoan chinh kiin true sau nhiiu lin thi nghiem thoi gio.

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N h im k it thuc thilt kl c u li ciing, b it ddu thf nghiem md hinh khf dpng dan hdi chfnh xdc hon. Thdi khf dpng dan hdi lam md hinh bj udn dang tuong ty nhu cdng trinh thyc: dung ty le dp cdng, dung khii lupng vd giam dao dpng. Cdc thf nghiem khf dpng dan hdi dd cd t hi thyc hien mpt sl md hinh cao hem dang tjnh t i ln cua dao dpng. " " "^ " "^

^1 ^ Cdc dang cao hon nay chi phli cdc phan dng k it c lu vd thilt kl ciia thap, ngoai trU mdng d dd da kiem tra thf nghiem. Dya tren k it qua cua cdc md hinh khf dpng dan hdi, cdc chuyen djch cdng trinh da dupc dy bdo phij hpp vdi gid trj yeu c lu trong tieu chuan ISO md khdng c in phu trp gidm dao dpng. • Hinh 12: ap Iffc hut giam theo dien tich mat hffng gio giam len cao (Cdn nOra)

Abstract: The goal of the Burj Dubai Tower is not simply to be

luc dupc thyc hien mpt vdi vung nhu thdp bj gid thdi b ic len, bay ra vd hinh dang k i ln true dupc thilt kl dilu chlnh lai. Ba cdnh thdp l ln lupt hung gid xoay theo chilu kim d i ng hi vdi cdnh A hung gid ddu tien (Hinh 10& 12).

the world's highest building; it's to embody the world's highest aspi rations. The superstructure is final construction and as of fall 2008 and has reached over 162 stories, 818m tall. The final height of building is not a" well - guarded secret". The heigh of the multi- use skyscraper with 280 000 m^ (3,00G,000ff) Gross area tower multi- use will " comfortably" exeed the current record holder, the 509 meter (1671ft) tall Taipei 101. The Dubai Renames world's Tallest Tower Burj Khalifa, Official celebrace openning in January of 2010 and utilized for retail, Giorgio Armani Hotel, residential and office.

NGUdi XAY DUNG S6 THANG 6 • 2011

Sau mdi dpt thd nghiem I ng thdi gid, cdc dd lieu dua vdo phan tfch vd kiin true toa nha lai dieu ehinh de gidm thieu hieu umg gid vd phu hpp vdi nhung thay ddi md khdng lien quan trong ehuong trinh cua khdeh hdng. Nhin chung, sl lupng vd khodng cdch giua cdc l ln thyc hidn thay ddi nhu dd Idm Id c h ip nhdn dupc. Kit qud qud trinh ndy ddn d in dp lyc gid len thdp giam ddng ke bdng cdch "xdo dpng" gid "khulch tdn" xody khdng theo quy ludt md chi hudng theo chilu cao. As with all super-tall project, difficult structural engineering problems needed to be addressed and resolved. This paper pres ents the Super -tall Building Design Approach in Engineering experi ence for the Burj Dubai.