Nha Nhieu Tang

8/7/2019 Nha Nhieu Tang

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Ket cau nha nhieu tang

CHNG 1

GII THIEU CHUNG

I. Khai niem ve nha nhieu tang1Nha nhieu tang, c phan loai theo nhieu tieu ch khac nhau, tuy thuoc vao ieu kienkinh te xa hoi cua tng nc.

Theo Uy ban Quoc te ve nha nhieu tang: Nha nhieu tang la nha ma chieu caocua no anh hng en y o va cach thc thiet ke. Hay noi cach khac, mot congtrnh xay dng c xem la nhieu tang tai mot vung vao mot thi iem nao o, neu

chieu cao cua no quyet nh cac ieu kien thiet ke, thi cong hoac s dung khac vi

nha thong thng;

Theo Taranath: Nha nhieu tang la nha ma khi tnh toan bat au chuyen t phantch c hoc sang phan tch ong lc hoc.

Phan tch c hoc bao gom: phan phoi lc hp ly;

Phan tch ong hoc: phan tch chuyen v, dao ong, on nh.

Trong cuoc hoi thao quoc te ve Nha nhieu tang, ngi ta a phan loai nh sau:- Nha nhieu tang, la nha co so tang: n = 10 12 tang;- Nha cao tang: n = 25 30 tang;- Nha choc tri: n > 30 tang.

Hnh 1. 1 Phan loai nha nhieu tang

1 o cao nha c tnh t mat at ngoai nha en diem mai cong trnh, khong ke o cao cac bo phan nho le nkhoi mai: benc, buong thang may.

Giang vien: Th.S Le c Hien Trang 1/43


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Tuy nhien, cac nh ngha tren cung ch la qui c, thay oi theo ieu kien kinh te xahoi cua tng quoc gia. V du:

Lien xo cu: Nha 10 tang tr len, cac nha khac 7 tang;

Hoa ky: Nha tren 7 tang hoac cao hn 22m;

Cong hoa Phap: Nha cao tren 50m, loai nha khac tren 28m;

Vng quoc Anh: Nha co chieu cao t 24.3 tr len;

Nhat Ban: Nha 11 tang va cao t 31m tr len,

II. Mot so cong trnh nhieu tang tieu bieu:2.1 Tren the gii:

Hnh 1. 2 Petronas Twin Tower



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2.2 Viet Nam

Hnh 1. 3 Saigon Trade Center 33tang



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CHNG 2

TAI TRONG TAC ONG LENNHA NHIEU TANG

Tai trong tac dung len nha nhieu tang co nguon goc a vat ly (trong lc, kh hau va achan) hoac nhan tao (tai trong s dung)

I. Tai trong thang ngTai trong thang ng tac dung len cong trnh nha thng gom hai loai: tnh tai (tronglng ban than cua cong trnh) va hoat tai (tai trong s dung).

Trong nha nhieu tang, kha nang xuat hien ong thi tai trong s dung tat ca cac tang

se giam khi so tang tang len. V vay, hau het cac tieu chuan eu a ra he so giam tai.Theo TCVN 2737 -1995, he so giam tai c qui nh:

a) Khi tnh dam chnh, dam phu, ban san: tai trong toan phan c phep giam nhsau:

Khi dien tch san A A1 = 9m2, th:1

1AA/A

6.04.0 += (2. 1)

Khi dien tch san A A2 = 36m2, th:2

2/

5.0

5.0 AAA += (2. 2)

b) Khi xac nh lc doc e tnh cot, tng, mong: tai trong toan phan c phep giamnh sau:

oi vi cac phong neu muc 1, 2, 3, 4, 5 (bang 3, theo TCVN 2737 -1995):n

4.04.0 1A1n

+=

(2. 3)

oi vi cac phong neu muc 6, 7, 8, 10, 12, 14 (bang 3, theo TCVN 2737 -1995):

n

5.05.0 2A2n

+= (2. 4)

(vi n so san pha tren tiet dien ang xet).

Tuy nhien, hoat tai thng khong ln hn trong lng ban than (bang 15 -20%) nen khithien ve an toan co the khong xet en he so giam tai. Trong tnh toan khung nhieutang, nhieu nhp nhat la he khung khong gian con cho phep khong xet en cac trnghp bat li cua hoat tai tren cac san.



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II. Tai trong ngang (gio)Tac dung cua gio len cong trnh la tac dung ong, no phu thuoc vao cac yeu to

cua moi trng xung quanh nh a hnh va hnh dang cua manh at xay dng, omem va ac iem mat ng cua cong trnh va s bo tr cua cac cong trnh lan can.

Sau ay, ta hay phan tch mot so ac trng cua tai gio: van toc gio, hng gio:

Van toc gio: thong thng van toc gio tang theo chieu cao, mc o tangcua gio phu thuoc vao ac iem be mat at. Cang gan mat at, do anhhng cua ma sat nen gio tat dan

Cac oi tng xung quanh anh hng rat ln en chieu cao at van toc ccai cua gio.

Aplc gio: ap lc gio c gay ra bi hai yeu to van toc trung bnh va vantoc gio giat. Van toc trung bnh xem nh la gia tr trung bnh cua van toc tnhtrong thi gian dai va do o ap lc tnh cung la ap lc trung bnh va no gayra o vong tnh cho cong trnh. Gio giat cua ap lc ong gay ra tac dungong lam tang them chuyen v. Con oi vi cong trnh mem gia tr chuyen vco the ln hn.

Gio quan: khi luong kh gap chng ngai, no phai i vong qua ben va taothanh dong kh co van toc ln. Van toc gio tang theo khoi lng kh i qua.Khi o xuat hien gio quan

Khi luong gio chuyen ong vt qua khe hep gia hai nha nhieu tang sexuat hien gio quan. Van toc gio vung khe hep nay co van toc ln hn vantoc gio en (hieu ng Venturi).

S cam thu cua con ngi ve tac ong cua gio: s cam thu cua con ngive tai trong gio ca trong va ngoai cog trnh la yeu to quan trong can xet enkhi thiet ke nha nhieu tang. Nhng dao ong manh cua vo ngoai, mac duket cau chu lc co the chu c nhng can phai giam en tr so chuyen vgii han cho phep oi vi con ngi.

Tai trong gio theo tieu chuan xay dng (TCVN 2737 -1995)

Tai trong gio gom hai thanh phan: thanh phan tnh va thanh phan ong. Theo TCVN2737 -1995, khi tnh toan nha di 40m (xay dng a hnh dang A va B), thanh phanong cua tai gio khong can tnh en.

Gia tr tieu chuan thanh phan gio tnhc tnh theo cong thc:ckWW = 0 (2. 5)



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Trong o: W0 gia tr ap lc gio, lay theo ban o phan vung; k he so ap lc gio thayoi theo o cao; c he so kh ong.

Gia tr tieu chuan cua thanh phan ong cua tai gio tac dung len nha nhieu tang,Wp cao o Z, tnh theo cong thc (2.6):

=WWp (2. 6)

Trong o, W gia tr tieu chuan cua thanh phan tnh tai cao o tnh toan; -he so ap lcong cua tai gio; -he so tng quan khong gian ap lc ong cua tai trong gio.



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Trnh t cac bc tnh toan xac nh thanh phan ong cua tai trong gio

Xac nh xem cong trnh co thuoc pham vi phai tnh thanh phan ong hay khong. Thiet lap s o tnh ong lc

S o tnh toan c chon la he thanh console co hu han iem tap trungkhoi lng

Chia cong trnh thanh n phan sao cho moi phan co o cng va ap lc gio lenbe mat cong trnh co the coi nh khong oi

V tr cac iem tap trung khoi lng c at tai cao trnh trong tam cua cacket cau truyen tai trong ngang cua cong trnh (san nha)

Gia tr khoi lng tap trung tai cac cao trnh bang tong cac gia tr khoi lngcua ket cau chu lc, bao che,



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o cng cua console lay bang o cng tng ng cua cong trnh, sao chochuyen v cua nh cong trnh va console la nh nhau khi chung chu mot taingang nh

Xac nh gia tr tieu chuan thanh phan ong cua tai trong gio, khi ch ke en anhhng xung cua van toc gio.

Xac nh he so ap lc ong va he so tng quan khong gian Xac nh gia tr tieu chuan thanh phan ong cua tai trong gio, khi ch ke en

anh hng xung cua van toc gio Xac nh gia tr tieu chuan va tnh toan cua thanh phan ong cua tai trong gio len

cac phan tnh toan cua cong trnh. Bao gom: Xac nh tan so va dang dao ong. Xac nh tan so dao ong th nhat f1 cua

cong trnh. So sanh tan so f1 vi tan so gii han fL. Khi , thanh phan

ong cua tai trong gio ch can ke en tac dung cua xung van toc gio. Ngclai, khi , thanh phan ong cua tai gio phai ke en tac dung cua xung

van toc gio va lc quan tnh cua cong trnh.

Lff >1

Lff 1

Xac nh gia tr tnh toan cua thanh phan ong tai trong gio To hp noi lc va chuyen v cua cong trnh do thanh phan tnh va ong cua tai

trong gio gay ra.

Xac nh thanh phan ong cua tai trong gio theo TCVN 2737 -1995

Tuy vao mc o nhay cam cua cong trnh oi vi tac dung ong lc cua tai tronggio ma thanh phan ong cua tai trong gio ch can ke en tac ong do thanh phanxung cua van toc go hoac ca lc quan tnh cua cong trnh.

Mc o nhay cam c anh gia thong qua tng quan gia tan so dao ongrieng c ban (ac biet la tan so rieng th nhat) va tan so gii han fL:fL (Hz)

Vung ap lc gio Cong trnh BTCT va gacha

Cong trnh dang thap tru

I. 1.1 3.4II. 1.3 4.1III. 1.6 5.0IV. 1.7 5.6

V. 1.9 5.9

Khi , thanh phan ong cua tai trong gio ch can ke en tac dungcua xung van toc gio. Gia tr tieu chuan thanh phan ong cua ap lc gio(W

Lff >1

pj) c tnh theo cong thc:1 jjpj WW = (2. 7)

Trong o:Wj gia tr tieu chuan thanh phan tnh cua ap lc gio tac dung len phan th jcua cong trnh; j -he so ap lc ong o cao ng vi phan th j cua cong

trnh; 1 -he so tng quan khong gian ng vi dang dao ong th nhat cuacong trnh.



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Khi Lff 1 , thanh phan ong cua tai gio phai ke en tac dung cua xungvan toc gio va lc quan tnh cua cong trnh. Khi o, so dang dao ongau tien can tnh toan (s) xac nh theo bieu thc:

1+


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Cong thc (2):D

HT 09.0= (2. 15)

(H chieu cao tnh t e en nh nha, tnh bang m; D be rong mat on gio, m)Cong thc (3): HT = 021.0

Vi T chu ky dao ong rieng cua ngoi nha, tnh bang sec;H chieu cao tnh t e en nh nha, tnh bang m;

2- Tng t nh cach xac nh tai trong gio tnh theo bieu o hnh thang, cac gia tr thanh phanong cua ap lc gio c xac nh nh sau:

Tai nh nha:( ) c.k1Wq 0

p +=;

Tai e nha:cW65.0q 0

p =

Vi W0 ap lc gio tieu chuan, lay theo bang phan vung ap lc gio;

k he so ap lc gio tang theo chieu cao; c he so kh ong; -he so ap lc

ong tai nh nha;

Tai iem bat ky tren chieu cao ngoi nha, ap lc gio c xac nh theo cong thc:

+= XH

aqq px

11 , X toa o tnh t nh nha

V du ap dung: Xac nh tai trong gio cho cong trnh sau.

III. Tai trong ong at (theo ch dan ieu 3.1.3 TCXD 198 -1997)



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CHNG 3

CAC DANG KET CAU CHU LCVA S O LAM VIEC

I. Cac dang ket cau chu lc1.1 Cac he ket cau chu lc c banHe ket cau chu lc Nha nhieu tang la bo phan chu yeu tiep nhan tai trong ng, ngangtruyen xuong mong. Nhn chung, he chu lc c cau tao t cac dang ket cau sau:

He ket cau khung chu lc (cau kien dang thanh: dam, cot); He tng, vach chu lc;

He ket cau khong gian: loi cng, li, ong,

T cac thanh phan ket cau chnh neu tren, tuy thuoc vao cac giai phap kien truc, khichung c lien ket vi nhau theo yeu cau cau tao nhat nh se tao thanh ca he chulc khac nhau theo s o sau:

Sau ay la s lam viec cua mot so he ket cau tren

He khung chu lc (I): he nay c tao thanh t cac cot, dam lien ket vi nhautheo hai phng tao thanh he khung khong gian. Tren mat bang, he khung co theco dang ch nhat, tron, hoac a giac Trong Nha nhieu tang, tac dung cua taitrong ngang ln. e tang o cng ngang cua khung, ong thi co the phan phoieu noi lc trong cot, bo tr them cac thanh xien tai mot so nhp tren toan bochieu cao hoac tai mot so tang. Tac dung cua he thanh xien (dang dan) lam chokhung lam viec nh vach cng thang ng;


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Hnh 3.1: Nha co he khung chu lc

Neu thiet ke them cac dan ngang ( tang tren cung hoac mot so tang trung gian) lienket dan ng vi cac bo phan con lai cua khung th hieu qua chu tai ngang cua khungtang ang ke.

Di tac dung cua tai trong ngang, cac dan ngang se ong vai tro phan phoi lc docgia cac cot khung, can tr chuyen v xoay va lam giam mo-men phan di cuakhung.

He khung chu lc thuan tuy, co o cng uon thap theo phung ngang nen b han ches dung trong nha co chieu cao tren 40m. Trong kien truc nha nhieu tang, luon conhng bo phan nh thang may, thang bo, tng ngan hoac ket cau bao che lien tuctheo chieu cao nen ket cau khung chu lc thuan tuy thc te khong ton tai.

San cac tang trong nha khungco vai tro quan trong trong viec truyen tai trong ngang.



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He tng chu lc (II): he ket cau nay cac cau kien thang ng chu lc ngva ngang cua nha la cac tam tng phang, thang ng vach cng. Tai trongngang c truyen en cac vach cng thong qua ket cau san, c xem la tuyetoi cng trong mat phang cua chung. Cac vach cng lam viec nh nhngconsole ng, co chieu cao tiet dien ln.

Kha nang chu tai cua vach cng phu thuoc rat ln ve hnh dang tiet dien ngangva v tr bo tr chung tren mat bang. Ngoai ra, trong thc te cac vach cng thngb giam yeu do co s xuat hien cac lo ca.

Hnh 3.2: He tng chu lc

He loi chu lc (III):Loi co dang vo hop rong, tiet dien kn hoac h, nhan cac loai tai trongtac ong len congtrnh va truyen xuong mong. Trong Nha nhieu tang, loi cng thng c bo tr ket hpvi v tr thang may.

Hnh dang, so lng, v tr bo tr cac loi cng chu lc tren mat bang rat a dang.

Nha loi tron, vuong, ch nhat, (dang kn hoac h); Nha co mot hay nhieu loi; Loi nam trong nha, theo chu vi hoac ngoai nha.



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Hnh 3.3: He loi chu lc

He hop chu lc (IV):Cac ban san c goi vao cac ket cau chu tai nam theo chu vi cong trnh ma khongcan goi vao vao ket cau chu tai ben trong. Vi dang ket cau nay, se tao ra mot khonggian ln ben trong nha.

Tuy theo cach to hp, cac ket cau chu lc co the chia theo hai nhom: Nhom th nhat: ch gom mot loai cau kien chu lc oc lap nh khung,

tng, vach, loi chu lc;

Nhom th hai: la cac he chu lc c to hp t hai, ba loai cau kien c bantr len.



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1.2 Cac he ket cau hon hpCac he ket cau hon hp c tao thanh t s ket hp gia cac he ket cau c ban tren:

He khung vach: ket cau khung vach thng c s dung hn ca v he nay phuhp vi hau het cac giai phap kien truc cua nha nhieu tang. He ket cau nay taoieu kien ng dung linh hoat cac cong nghe XD khac nhau nh va co the lapghep, va o tai cho.;

He khung loi chu lc; He khung hop chu lc; He hop loi chu lc; He khung hop tng chu lcII. S o lam viec cua cac dang ket cau chu lcTrong he ket cau hon hp, tuy thuoc va s hien dien cua ket cau khung ma ngi tachia s o lam viec cua ket cau dang s o giang hoac s o khung giang.

2.1 S o giang


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Khi khung ch chu c phan tai trong thang ng tng ng vi dien tch truyen taien no. Toan bo tai trong ngang va mot phan tai trong thang ng se do cac ket cauchu tai c ban (loi cng, vach cng,) khac chu. Trong s o nay, cac nut khung euco cau tao nut khp hoac tiet dien cot co mo-men khang uon nho.

Theo cach quan niem nay, tat ca cac he chu lc c ban va hon hp tao thanh t cactng, loi, thuoc s o giang.

Hnh : S o giangKhung B (ch co kha nang chu tai ng) c xem la b giang bi khung A (co kha

nang chu tai ngang)

Hnh : So khunggiang



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2.2 S o khung giangKhi khung cung tham gia chu tai trong thang ng va ngang vi he ket cau khac.Trong trng hp nay, cac nut khung lien ket cng. Nh vay, theo cach hieu nay, hekhung chu lc c xep vao s o ket cau khung giang.

Co the phan loai s o giang va s o theo chuyen v hoac o cng nh sau:


8.01B

A

: khung giang

hoac :BA K5K

2.3 Chon s o ket cauQua nghien cu cho thay rang, ngi ta thng s dung nhng s o sau:

Khung chu lc: Khung chu lc ngang yeu. Nha nhieu tang chu tai ngangln, nen han che s dung s o khung chu tai ngang.

Tng chu lc: chu tai ngang ln, nhng han che khong gian s dung; Tng chu lc ket hp vi khung: tng chu lc ngang, khung chu lc ng

hp ly trong s o ket cau va bo tr kien truc. V vay, ay la dang ket cauthng s dung nhat trong Nha nhieu tang.

He thong vach cng thng c tao ra tai khu vc cau thang bo, cau thangmay, khu ve sinh chung hoac tng bien lien tuc nhieu tang. He thongkhung c bo tr khu vc con lai. Hai he thong khung va vach cng clien ket vi nhau thong qua he thong san. Trong trng hp nay, he ket cau

cau san toan khoi co y ngha rat ln trong viec truyen tai trong ngang chovach cng.

Trong thiet ke va xay dng nha nhieu tang, viec la chon he ket cau hp ly phu thuocvao nhieu yeu to nh: chieu cao, ieu kien a chat thuy van, ban o phan vung ongat va cac giai phap kien truc cong trnh.

Co the chon la ket cau hp ly he ket cau chu lc theo so tang tren o th sau:


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Hnh : S o la chon he ket cau theo so tang


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Ngoai ra, e am bao o cng, han che chuyen v ngang va tranh mat on nhtong the, can han che chieu cao va o manh (ty le chieu cao tren be rong congtrnh) theo ch dan sau:

Bang :Chieu cao toi a H(m) va ty so gii han gia chieu cao va chieu rong (H/B)

Trng hp co ong at capHe ket cau Trng hpkhong co ongat 6 va 7 8 9

Nha khungchu lc

Max H (m)

Max H/B

60

5

55-60

5

45

4

25

2

Nha vach vakhung ong

Max H

Max H/B

130

5

120 -130

5

100

4

50

3Nha vach Max H

Max H/B

140

5

120 -140

6

120

5

60

4

Nha ong vanha ongtrong ong

Max H

Max H/B

180

6

150 -180

6

120

5

70

4


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III. Tng cng chu lc (shear wall)3.1 Pham vi ap dungTng cng chu lc (cat) thng c bo tr trong nha nhieu tang, dung e chu toan

bo hay phan ln tai trong ngang (gio, ong at). Tng chu cat lam viec nh ket cauconsole ngam vao mong, chu tac dung cua lc doc, lc cat va mo-men uon. Khi ty lechieu cao/chieu dai tng nho, anh hng cua noi lc cat trong tng la ang ke vacan phai lu y trong thiet ke. Chieu cao cua tng b khong che bi yeu cau ve uon(mo-men, bien dang ngang).

Theo nhieu tai lieu, pham vi s dung

3.2 Cach bo tr tng cngViec bo tr v tr cua tng cng tren mat bang rat quan trong v no anh hng trc tiepen viec phan bo tai trong ngang len ket cau. Theo kinh nghiem, khi bo tr can chu y

en cac ac iem sau: Tng cng c bo tr cac vach ngan: cach nay gay lang ph ton nhieu

vat lieu cho tng va chi ph ve nen mong;

Thng tap trung gia, tao thanh vi cau thang tao thanh loi, chu tai trongngang kha tot;

Vi cong trnh co mat bang hnh vuong, nen bo tr tng theo hai phngvuong goc nhau.

Vi cong trnh co mat bang chay dai, ngoai viec tap trung tng gia conphai botr hai au hoi e han che o vong ngang.

Phai bo tr t nhat ba vach tren mot n nguyen, truc ba vach nay khong gapnhau tai mot iem;

Nen thiet ke cac vach giong nhau (ve o cng va hnh hoc) va bo tr sao chotam cng cua he trung vi tam khoi lng cua no;

Khong nen chon cac vach co kha nang chu tai ln nhng so lng t machon nhieu vach co so lng chu tai tng ng va ph6n bo eu tren matbang.

3.3 Chon chieu day tng Tong dien tch mat cat ngang cua vach cng (loi cng) co the xac nh theo

cong thc:

stvlvl FfF =

Trong o: Fst dien tch san tng tang; fvl = 0.015

Tng vach nen co chieu cao chay suot t mong en mai va co o cngkhong oi tren toan bo chieu cao cua no;

o day toi thieu cua vach, qui pham cac nc khac nhau qui nh khac nhaunhng nhn chung khong nho hn 100mm. Chang han:Theo TCXD 198 -1997 cua Viet Nam: Be day thanh vach (b), chon khongnho hn 150mm va 1/20 chieu cao tang.



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Theo ACI 318-02 (muc 14.5.3), Be day thanh vach (b), chon khong nho hn100mm va 1/25 chieu cao tang.

3.4 Cau tao cot thep cho vach (loi) cng (muc 3.4.2TCXD 198 -1997) Cot thep phai c at hai lp li. ng knh cot thep (ng va ngang)chon khong nho hn 10mm va khong ln hn 0.1b. Hai lp thep phai c

lien ket vi nhau bi cac moc ai (mat o 4 moc/ m2);

Ham lng cot thep thang ng toi thieu (min) va toi a (max):oi vi khu vc ong at yeu, %4.0min =

oi vi khu vc ong at trung bnh va manh, %6.0min =

Va trong hai trng hp tren, %5.3max =

Khoang cach cot thep (ng va ngang), chon 200 (khi b 300) va chon 2b/3 (khi b > 300);

Chieu dai noi buoc cot thep lay bang 1.5lbo (vung ong at yeu) va 2.0lbo(vung ong at trung bnh manh). Trong o, lbo chieu dai noi tieu chuantrong vung khong co ong at (tc lneo);

Can co bien phap tang cng tiet dien khu vc bien cua vach cng (xemhnh 3.12)



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STT Nen chon Nen tranh Giai phap khac phuc

1.

B

L

B

L

B

K

LKhekhangchan

2.

B

L

B

L

B

L

B

L

B

L

3.L

CB/4

B

L

C>B/4

B

Dung khe khang chan Ktach nha thanh cac nnguyen nho, oc lap va

oi xng

Trong nha nhieu tang, thng co tang ham nen viec bo tr cac khe bien dang nhat la

khe lun gay nhieu phc tap cho ky thuat chong tham. Gia khoi nha cao tang va thaptang co the khong bo tr khe lun ma ch co khe co gian t mat mong tr len mot khi aap dung cac bien phap sau:

S dung coc chong vao tang a, hoac tang cuoi soi vi o sau thchhp ong thi chng minh c s chenh lun nam trong pham vi chophep;

Tien hanh thi cong phan cao trc, phan thap tang sau.2.2 Hnh dang phng ng nhaTheo phng ng, nha phai n ieu va lien tuc, can oi

n ieu va lien tuc, hnh dang nha nhieu tang nen la chon dang euhoac thay oi eu, giam dan kch thc len pha tren nham giam hau qua



24/60



bat li cua tac ong ong at. Khi hnh dang nha khong lien tuc, bien o daoong se ln mot so tang. Luc nay phai thiet ke cac vach cng ln tai cacvung chuyen tiep e truyen tai trong t phan nay sang phan khac cua congtrnh.

Can oi, khi cong trnh co ty so chieu cao tren be rong (H/B) ln, khi chu taingang se co chuyen v ngang ln. Lc doc trong cot bien do tai ngang lndan en lc nen tac ong xuong mong ln.

Khong nen at cac tai trong s dung ln len cac tang caoTheo TCXD -198: 1997, ty so gii han B/H nh sau:

Loai ket cau Khong khangchan

Khang chan,cap 7

Khang chan,cap 8

Khang chan,cap 9

Khung 5 5 4 2Khung vach 5 5 4 3

Tng 6 6 5 4Ong 6 7 5 4

Tren mat cat thang ng, cong trnh c thiet ke oi xng (oi xng khoi lng va ocng) theo ch dan bang 2


25/60


Nencho

n

H

B

H

B

Nen

tranh

H

>B/4

B

H

>0.1B B

Giaiphapkhacphuc

H

B

H


26/60


IV. La chon va bo tr khe co gian, khe lun va khe khang chan (nguyen tac tht)

Nguyen tac bo tr cac khe co gian, khe lun va khe khang chan la ieu chnh kch thcmat bang. Dung cac bien phap cau tao va ky thuat nham giam toi a so lng khe v

giam so lng khe la giam tai trong va so iem can x ly phc tap;Trong cac trng hp sau ay phai cat nha va cong trnh ra nhng phan rieng biet (nnguyen) bang cac khe co gian, khang chan:

Nha co kch thc mat bang ln (> 40m); Nha va cong trnh co hnh dang mat bang phc tap; Cac phan noi gia cac nha cong trnh co o cao chenh lech cao t 5m tr

len hoac mot tang

Cac khe khang chan va co gian phai cat nha theo toan bo chieu cao nhng khong nhat

thiet i qua mong (tr khi trung vi khe lun);Chieu rong toi thieu cua khe khang chan co the xac nh theo cong thc:

mm20VVD 21min ++=

Vi V1, V2 chuyen v cc ai theo phng ngang cua hai khoi ket cau ke nhau di tacdung cua tai trong ong at.

V. o cng va cng o la chon giai phap s o khung chu lc (nguyen tacth nam)

Nen tranh s thay oi ot ngot cua s phan bo o cng va cng o theochieu cao nha. Neu cong trnh co mot tang mem, cac bien dang ln cokhuynh hng tap trung tang o va de gay ra sup o toan bo cong trnh.Trng hp nay thng gap cac nha c thie ke vi hai chc nang: tangtret he khung (am bao co mat bang thoang, phuc vu cho khong gian ln);cac tang tren he vach cng. e khac phuc, tang o cng tang mem bangcach tang tiet dien cot hoac bo tr cac vach cng lo ca;

Khong nen thiet ke khung thong tang va khung co nhp khac nhau. Neutrong cung mot tang, va co cot ngan va cot dai, lc cat se tap trung cotngan nhieu hn (do o cng ln hn). ieu nay cung se xay ra tng t nh

oi vi dam ngan. Neu phai thiet ke cac nhp khac nhau, nen chon o cnggia cac nhp dam tng ng vi khau o cua chung.

L1 L2 L3

L1 L2 L3 L1 L2 L3



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Khi thiet ke nha khung, nen chon ket cau khung oi xng va co o sieu tnhcao. Neu la khung nhieu nhp nen chon chieu dai nhp gan bang nhau.Khong nen thiet ke khung co nhp qua khac nhau. Neu phai thiet ke nhpkhac nhau nen chon o cng gia cac nhp ty le vi khau o cua chung.

L1 L2 L3 L1 L2 L3 L1 L2 L3

Nen chon s o khung sao cho tai trong c truyen trc tiep va nhanh nhatxuong mong, tranh s dung s o khung hang cot tang di. Neu batbuoc phai hang nh vay, phai co giai phap cau tao e am bao nhan vatruyen tai trong t cot tang tren mot cach an toan

L1 L2 L3

L1 L2 L3

Khung be tong cot thep nha nhieu tang , neu co xay chen gach, trc hetphai chen cac tang di. Trong trng hp phai xay chen cac tang trenma tang di khong c xay chen th phai cau tao tang di sao cho co ocng ln hn;

L1 L2 L3L1 L2 L3



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Nen tranh thiet ke console (ke ca console dam va san). Trong trng hpcan co console phai han che o vn en mc toi thieu va tnh toan kiem travi tai trong ong at thang ng;

Cach thc pha hoai

Khi thiet ke khung, nen chon ty le o cng dam cot va gia cac oan damvi nhau sao cho khi pha hoai, cac khp deo se hnh thanh trong cac damsm hn trong cot (cot khoe dam yeu). Bi v:

Cot b pha hoai ngha la toan bo cong trnh sup o trong khi cha huy onghet kha nang chu tai cua cac bo phan khac. Mat khac, trong ket cau co cotyeu, bien dang deo se tap trung tai mot tang nao o. Do vay, can phai comot he so o deo tng oi ln.

Cac khp deo se hnh thanh trong cac dam sm hn trong cot ieu nay seat c neu tong mo-ment cho phep cua cac cot qui tu tai moi nut khung

ln hn tong cac mo-men cho phep cua cac dam tai nut o.

L1 L2 L3

L1 L2 L3

VI. La chon va bo tr cac vach va loi cng (nguyen tac th sau) Khi thiet ke cac cong trnh s dung vach va loi cng lam ket cau chu tai

trong ngang, phai bo tr t nhat 3 vach cng trong cung mot n nguyen.Truc cua ba vach nay khong c gap nhau tai mot iem;

Nen thiet ke cac vach giong nhau ve o cng (va ca ve kch thc hnh hoc)va bo tr sao cho tam cng cua he trung vi tam khoi lng cua chung

o cng cua cac vach chiem phan ln ty trong o cng cua toan nha. vvay, cac vach nen co chieu cao chay suot t mong len mai va co o cngkhong oi tren toan bo chieu cao cua no.



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CHNG 5

TNH TOAN KET CAU NHA NHIEU TANG

I. Cac khai niem chung2.1 Gia thiet tnh toan

Tnh toan ket cau nha nhieu tang la viec xac nh trang thai ng suat bien dangtrong tng he ket cau, tng bo phan ket cau cho en tng cau kien chu lc di tacong cua moi loai tai trong tac dung len cong trnh. ay chu yeu xet en phan ngcua he ket cau thang ng (khung, vach loi) di tac dung cua cac loai tai trong ngang;

Hau nh trong cac loai nha cao en 30 tang eu ket hp s dung cua ba he ketcau khung, vach, loi chu lc. Viec la chon va gia thiet s o tnh khong nhng phaiphu hp vi thc te bo tr, cau tao cua cac cau kien chu lc ma con phai thoa man ieukien ve s cung lam viec cua cac he ket cau von khac nhau ve hnh dang, kch thc

hnh hoc, o cng. Moi gia thiet thng ch phu hp vi tng mo hnh tnh toan vakhong co gia thiet chung cho moi s o tnh toan. Gia thiet nao phan anh c moiquan he truyen lc gia cac he vi nhau thong qua cac giai phap thiet ke, cau tao sec xem la phu hp va cho ket qua ang tn cay. Thng dung cac gia thiet sau:

S o tnh toan mot chieu: cong trnh c mo hnh hoa di dang motthanh console thang ng. o cng cua no c xac nh t ieu kienchong uon, trt va xoan cua cong trnh. Gia thiet nay tng oi n giannhng khong phan anh ung thc te chu lc cua ca he. Gia thiet nay thuantien cho cho viec xac nh cac ac trng ong hoc cua cong trnh.

S o tnh toan hai chieu: cong trnh c mo hnh hoa di dang mot ketcau phang vi ngoai lc nam trong mat phang o. Theo gia thiet nay, moi heket cau ch tiep thu mot phan tai trong ngang thong qua cac thanh giang colien ket khp hai au. Cac thanh giang ngang nay chnh la mo hnh cua heket cau dam san. S o nay c dung rong rai nhat v tng oi n gianlai xet en tac ong tng ho gia cac cau kien thang ng.

S o tnh toan 3 chieu: cong trnh xem nh mot he (thanh, vach) khonggian, chu tac ong cua he lc khong gian.


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2.2 Cac phng phap tnh toanTren c s cac s o tnh toan, chung ta co the chon la nhieu pp khac nhau

trong CHKC va trong toan hoc e xac nh noi lc va chuyen v trong he va trong tng

cau kien chu lc;Cac phng phap trong CHKC nh: PP lc, chuyen v, PP lc chuyen v vanc s dung co hieu qua cho tng trng hp cu the. Cac PP vi phan, bien phan e

Lx Lx Lx Lx Lx Lx Lx

Ly

Ly

Ly DAM

COT

VACH

- -

NA KHUNG TRUC1,2& 7,8

NA KHUNG VACHTRUC 3,4& 5,6

VACH

01

02

03

25

24

23


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giai cac he phng trnh bac cao con c s dung e giai cac s o giang, khunggiang.

Trong so cac PP tnh toan nha nhieu tang hien nay, PP. PTHH c s dungrong rai hn ca v hau het cac phan mem tnh toan eu s dung PP nay.

2.3 Cac bc tnh toan Chon s o tnh toan; Xac nh cac loai tai trong; Xac nh cac ac trng hnh hoc va o cng ket cau; Phan phoi tai trong ngang vao cac he ket cau chu lc; Xac nh noi lc, chuyen v trong tng cau kien; Kiem tra ieu kien ben, chuyen v va cac ac trng ong; Kiem tra on nh cuc bo, tong the cong trnh.

II. Tnh toan he chu lc theo s o phang2.1 He khung vachTrong nha nhieu tang, he chu lc khung vach thng c bo tr song song vi nhautheo mot hay hai phng tren mat bang nen co the dung s o khung giang e tnhtoan cho toan heTuy theo cau tao cua vach cng, co the co cac s o sau:

Khung vach ac (h. a) Khung vach ac va vach lien khung (h. b) Khung vach co lo ca (h. c)

Trc khi tnh toan ca he, ta xem xet s lam viec oc lap cua he khung nhieu tangnhieu nhp di tac dung cua tai trong ngang


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a/ Chuyen v ngang cua khung nha nhieu tangKhi tnh toan chuyen v ngang cua cua khung nha nhieu tang di tac dung cua

tai trong ngang co the xem mot cach gan ung rang goc xoay cua cac nut tren cungmot mot xa ngang la bang nhau. Nh vay, co the n gian hoa s o tnh chuyen v cuakhung nh sau:


Goi si la tong o cng n v cua cac cot tang th I; ri tong o cng n v cua cac xangang cua tang th i; lp gia tr trung bnh cac nhp cua xa ngang; li chieu cao tang thI va n so tang cua khung.Trong s o tren, chuyen v ngang do P = 1 c tnh:

[ 1111 rs12

1 += ]; (5. 1)

;r.4

lrs

12

1

k

2

kkkkk

++= (5. 2)

k

1kkkkkn1k,kikki

r.48

l.l... ++ +===== (5. 3)

Trong o,

=k

1 i

2

ik

s

lS

; (5. 4)

11

2

11

s.33.0r.4

lR

+= ;

( )

11

2

212

s.33.0r.4

llR

++

= ; (5. 5)

Va( )

1k

2

k1k1kk

r.4

llRR

++= ; k = 3, 4, 5 (5. 6)

Trong cac cong thc tren, so hang sk bieu th anh hng o cng cua cot en chuyenv cua khung; con rk bieu th anh hng o cng cua xa ngangChuyen v ngang cua khung tang th k do tai trong ngang at tat ca cac tang:

nkn22k11k P....P.P.y +++= (5. 7)

Khi so tang , co the tnh chuyen v ngang theo cong thc sau:6n

;=

=k

1i

ii c.Qyki (5. 8)

a3a2

b

s1s2

sk

si

sn

r1

r2

r1

rk

rn

lp

l1

l2

ln

li

lk

a1


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Trong o, , (5. 9)=

=n

ki

ik PQ ki

ci o lech cua tang do lc n v tac dung theo phng ngangoi vi khung nha nhieu tang, co ket cau eu an vi o cng n v s va r giong nhau

tat ca cac tang co the c xac nh:

+=r

1

s

1

12

lc

2

(5. 10)

Goi A la o cng chong trt cua khung (tc lc gay nen goc lech 1l

c.A== ),

Ta co: c

lA =

(5. 11)

Suy ra,( )11 rsl12

A +

= ; (5. 12)

Khi so tang , co the tnh chuyen v ngang cua khung c bieu dien bang phngtrnh vi phan sau:6n

( ) 0xpB

M.Ay..Ay.B

0

0''2IV = (5. 13)

Trong o, -tong o cng chong uon cua cot;= jBBB

B0 o cng chong uon cua khung khi ch ke en hai cot bien.

p

t

2

tb0

F

F1

b.F.EB

+= ; (5. 14)

b

Ft Fp

Trng hp khung oi xng, FFF pt == , ta co:2

bF.EB

2

b0

=

0

2

B

B1+=

; (5. 15)M0 mo-men ngoai lc o cao x;

at vay.B=2.A

Bm

= , ta co phng trnh:

( ) 0xp.mM.1

.m 202

2''IV2 =

(5. 16)

Nghiem cua phng trnh (3.20) co dang:

04321 Csh.Cch.C.m.CC ++++=

ViCi cac hang so tch phan;

C0 nghiem rieng, phu thuoc vao dang tai trong;

mx= , toa o khong th nguyen.



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oi vi nhng khung thong thng, co the bo qua so hang th nhat cua(3.17) va , v12 = 0

B

B

0

. Khi o, (3.17) co dang:

( ) 0xpB

M.Ay.A

0

0'' =++ (5. 17)

Cac ieu kien bien,+ ( ) ;00y = va ( ) ( )0Q0'y.A 0= + Khi tai trong phan bo eu, p(x) = p, suy ra:

( )20 xHp5.0M =

Giai phng trnh vi phan (3.23), vi cac ieu kien bien tren, ta c chuyen v ngangcua khung nh sau:

( )

++=33

42

B8

pH2

A2

pHy

432

0

42

2

(5. 18)

ay,

H

x= -toa o khong th nguyen; (5. 19)

H chieu cao tnh toan cua ngoi nha,

5.0n

nHH 0

= . (5. 20)

H0 khoang cach t mat tren cua mong en truc cua xa ngang tren cung;

Tai nh khung, , chuyen v ngang:1=

+=+=4

1A2

pH

B8

pH

A2

pHy

2p

2

0

42

(5. 21)

Vi, -ac trng o cng cua khung, co xet en anh hng cua lc doc trong cot,p

0

pB

AH= (5. 22)

Ket qua nghien cu cho thay, khi , co the bo qua anh hng cua

lc doc trong cot va trong tnh toan lay,

7.0p

12 =V du tnh toan

2.2 He khung vach (ac)Xet trng hp he vach ac giang vi khung theo s o khung giang. T gia thiet

san co o cng vo cung trong mat phang, khung va vach co cung chuyen v ngang,nen o cng cua he c viet nh sau:

(5. 23)vj BBB += Vi , tong o cng cot khung; -tong o cng cua vach cng; jB vBKhi tong o cng cot khung qua nho so vi tong o cng vach co the xem , nh

vay he co ng cong uon tuan theo phng trnh:vBB =

( ) 0xp.mM.1.m 2022

''IV2 = (5. 24)

Va li giai co dang:



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37/60


( ) ( ) ( )

+

== sh.ch.11

112

1pH''M

2

22

2

2

v (5. 28)

Lc cat trong trong vach:( )( )

+== shch11

pH

'MQ

2

2v (5. 29)

Lc cat trong cot khung:( )

+

== shch1pH

QQQ20p

(5. 30)

Lc doc trong cac cot bien cua khung xac nh t phng trnh can bangmo-men:

( ) ( )

+

=

= sh.ch.11

12

1

.b

pH

b

MMN

2

2

2

0 (5. 31)

Mo-men uon, lc cat cua he c cat cua he c phan phoi, vao cac vach ty le vi ocng cua chungBieu o noi lc va chuyen v cua he c the hien nh hnh sau:


2.3 Tnh toan he khung vach lien khung

Z0L0 L0Z0 Z0L0Z0 L0 L0Z0


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ay la dang ket cau co s o hon hp v trong cung mot truc va co vach cng va va co khung

oi vi cac vach lien khung, ta ch can xac nh tong o cng cua he cho tng trnghp cu the roi tien hanh tnh toan tng t nh he vach acTong o cng cua he trong trng hp chung c xac nh:

vkk BBB += , hoac vkBB (5. 32)

Vi Bvk tong o cng cua vach lien khung. o cng uon cua vach lien khungbao gom o cng cua vach va phan khung. e xac nh o cng uon cua phan khungthuoc vach ta phai xet en cac bien dang an hoi cua cac nut lien ket gia vach vadam. o cng nay goi la o cng trt, xac nh theo cong thc:

( ) ( ) ( )[ ]( )cd

0c0d0d

vki3il

21i61i1i3A

+++++

= (5. 33)

Trong o,id o cng tng oi cua dam khung lien vach (o cng tren 1m dai cua dam

khung trong 1 tang);ic o cng tng oi cua cot khung lien vach;

d

0

0l

Z= (5. 34)

L chieu cao tangTrng hp khung lien vach hai pha o cng Avk tang len gap oi. Neu khung giahai vach o cng trt cung c nhan oi nhng gia tr ic nhan 0.5.o cng cua he khung vach co vach lien khung bang tong o cng cac khung va va chlien khung:

( ) vk11 Arsl12

A ++= (5. 35)

Trong khung nha nhieu tang co 7.0p


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2.4 Tnh toan noi lc oi vi nha co s o vach cng va lo cuaTrong thc te thng hay gap cac vach cng co lo ca. Trong trng hp nay cac

cot tng thng co mo-men quan tnh ln hn nhieu cac lanh to. Tuy thuoc vao ty lekch thc cac lo ca ma nhng vach cng co mot day lo ca thng co ba kieu biendang ac trng c the hien nh hnh 6.25Ve mat toan hoc, co the phan biet ba kieu bien dang tren thong qua he so lien khoi (6.89):Viec tnh toan phan phoi tai trong ngang cho cac vach cng khac nhau trong trnghp nay c thc hien nh vach cng ac nhng thay mo-men quan tnh I i bang mo-men quan tnh tng ng It,i.Trong he vach cng co lo ca: cot se la cac vach cng thanh phan, co s >>ro cng chong trt cua he khung:

( ) ( ) l

r12

rl

12

rsl

12A

111=

+

=

(5. 39)

Vi =r tong o cng lanh ca trong pham vi 1 tangNeu ch co mot dai lanh to ca:

k.a

Bi

3

lt

lt

= , (5. 40)

vi12

h.LEB

3

ltlt

blt = ;2

0

lt

a

h4.21k

+= va 1

a

a

0

>= (5. 41)

Sau khi co A suy ra , y, M, N, Q.

V du


B

A

A

B

Ly=9.0m

Ly

LxLxLxLxLxLxLx=7.0m Lx

56.0m

18.0m


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Khung ket hp vi tng cng


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42/60




43/60



Tai lieu tham khao chnh

1. Ngo The Phong, Ly Tran Cng, Trnh Kim am, Nguyen Le Ninh. Ket cauBe tong cot thep, phan ket cau nha ca Nha xuat ban KHKT, 1998;

2. Nguyen Van Hiep Bai giang ket cau be tong cot thep 3, ai hoc bach khoaTp.HCM;3. Mai Ha San Nha Cao Tang chu tac ong cua tai trong ngang gio bao va

ong at.

4. TCXD 198 -1997, Nha cao tang Thiet ke va cau tao be tong cot thep toankhoi;

5. Tai trong va tac ong TCVN 2737-1995;6. TCXD 229:1999 Ch dan tnh toan thanh phan ong cua tai trong gio theo

TCVN 2737-1995;

7. W. Sull Ket cau nha cao tang Ban dch;8. Athur Nilson Design of Concrete Structure -1997


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Tinh toan tai trong gio tac dunglen Nha Nhieu tang

(Chieu cao tang)

1. Ap lc gio tnh, Wj(z):

He so k (a hnh C) va he so kh ong c:

kC z( ) 0.3459 z0.2793

m0.279

:=

c 0.8 0.6+:= c 1.4=

Wj z( ) W0 kC z( ) c:=

2. Ap lc gio ong, Wfz(z):

- Chu k dao ong rieng cua ngoi nha c xac nh theo cong thc gan ung

T 0.021 H:=T 1.386 m=

T 1.386sec:=- Tan so dao ong rieng c ban f1

f11

T:=

f1 0.722 Hz=

- Gia tr ti han cua tan so dao ong rieng, fL (Vung II, Bang 2)

fL 1.3Hz:=

Do f1 fL< 1= nen gia tr tieu chuan thanh phan ong, Wfz, cua tai trong gioc xac nh theo ieu 4.7(TCXD 229-99)

Wfz 1.4z

H WpH:= WpH

Trong o:

+ - He so ong lc ng vi dang dao ong c ban cua cong trnh (tc ngvi tan so f1), xac nh theo Hnh 2, ieu 4.5

1 W0

940 f1

kg0.5

s

m

1

:= 1 0.015=

CLIENT SINH VIEN

PROJECT CONG TRINH 20TANG

JOB No VD-01

CALCULATION BY ThS. LE DUC HIEN

CHECKED BY

APPROVED BY

OBJECT XAC DINH TAI TRONG GIO THEO TCVN

2737-95& 229-99

- Ap lc gio tieu chuan (Vung IIA) W0 83 kg

m2

:=

He so vt tai: 1.2:=

- Chieu cao cong trnh H 66m:=

zmin 0.001m:= zmax H:= n 20:= (So tang)

z zmin zminzmax zmin

n+, zmax..:=

02/12/2006 1


45/60


Wt z( )

5.839

60.202

76.279

88.537

99.011

108.419

117.108

125.274

133.039

140.488

147.677

154.651

161.442

168.076

174.573

180.949

187.217

193.39

199.477

205.485

211.423

kg

m2

= z( )

2.12610 -4

0.073

0.12

0.161

0.198

0.233

0.266

0.297

0.327

0.356

0.384

0.411

0.438

0.464

0.489

0.514

0.538

0.562

0.586

0.609

0.632

=Wfz z( )

1.24110 -3

4.096

8.191

12.286

16.38

20.475

24.57

28.665

32.76

36.854

40.949

45.044

49.139

53.234

57.328

61.423

65.518

69.613

73.707

77.802

81.897

kg

m2

=Wj z( )

5.838

56.106

68.088

76.251

82.63

87.944

92.538

96.609

100.28

103.633

106.728

109.607

112.304

114.843

117.244

119.525

121.7

123.778

125.77

127.683

129.526

kg

m2

=j z( )

2.483

0.799

0.725

0.685

0.658

0.638

0.621

0.608

0.597

0.587

0.579

0.571

0.564

0.558

0.552

0.547

0.542

0.537

0.533

0.529

0.525

=kC z( )

0.05

0.483

0.586

0.656

0.711

0.757

0.796

0.831

0.863

0.892

0.918

0.943

0.966

0.988

1.009

1.029

1.047

1.065

1.082

1.099

1.115

m0

=z

110 -3

3.301

6.601

9.901

13.201

16.501

19.801

23.101

26.401

29.701

33

36.3

39.6

42.9

46.2

49.5

52.8

56.1

59.4

62.7

66

m

=

Wt z( ) Wj z( ) 1 z( )+( ):=

z( )Wfz z( )

Wj z( ):=at

3. Tong Ap lc gio tnh& ong, Wt(z):

Wfz z( ) 1.4z

H WpH:=Cuoi cung,

WpH 47.949kg

m2

=WpH Wj H( ) j H( ) :=Suy ra,

j H( ) 0.525=j z( ) 0.944 z0.14

m0.14( ):=

+ H- He so ap lc ong o cao H cua cong trnh, tnh theo bang 3(a hnh C)

0.705:=

+ -He so tng quan ap lc ong, lay theo bang 4& 5:

Trong o:WpH Wj H( ) j H( ) :=

+ WpH - gia tr tieu chuan thanh phan ong cua ap lc gio o cao H cuanh cong trnh, xac nh theo cong thc (4.1)

1.22:=Tra bieu o 2, ta c:

02/12/2006 2


46/60


4. Tnh ap lc gio tnh toan phan bo eu tng ng:

+ Be rong cong trnh, B: B 56m:=

+ Mo men tai chan cong trnh, M0:

M0 B 0

H

zWt z( ) z

d:= M0 2.463 107

kg m1

=

+ Tai lc gio phan bo eu tng ng, p

p z( )

2 M0

H2:= ptt p 0( ):= 1.131 10

4

kg

m1

=

+ Lc cat tai chan cong trnh, Q0

Q0

0

H

zp z( )

d:= Q0 3.746 105

kg m0

=

0 50 100 150 200 2500

10

20

30

40

50

60

70Tai trong gio tinh va dong

z

z

z

Wj z( ) Wfz z( ), Wj z( ) Wfz z( )+,

11.29 11.3 11.31

10

20

30

40

50

60

70Tai phan bo deu tuong duong

z

p z( )

103

02/12/2006 3


47/60

Lv 1800cm:= nv 3:=

+ Vat lieu: Eb 290.000kg

cm2

:=

+ Tai trong ngang tnh toan phan bo eu tng ng tac dung len cong trnh

p 11.31T

m:=

---------------------------------------------------------------------------------------------------------------------

1- Xac nh cac ai lng cua ket cau

+ Mo -men quan tnh cot:

Ic bchc

3

12

:= Ic 0.034m4

=

+ Mo -men quan tnh cua vach cng ac

Iv tLv

3

12:= Iv 97.2 m

4=

+ Tong o cng chong uon cua moi he chu lc oi vi truc i qua trong tam riengcua tng he:

B Eb 3Iv 18Ic+( ):= B 8.474 108

kgm2

=

+ Mo -men quan tnh oi vi trong tam cua he:

I0 6Ic 3Iv+ 12 Ic bc hc Y2

+( )+:= I0 914.294m4=

+ Tong o cng chong uon cua moi he chu lc oi vi trong tam cua toan he:

V du 2. Cho cong trnh co mat bang ket cau nh hnh ve:

Lx

56.0m

18.0m

Ly=9.0m

Ly

LxLxLxLxLxLxLx=7.0m

Cac d kien:

+ Mat bang, chieu cao: Lx 56m:= Ly 18m:= H 66m:= ht 3.3m:=

YLy

2:=

+ Tiet dien, so lng cot: bc 80cm:= hc 80cm:= nc 18:=

+ Tiet dien, so lng Dam hd 55cm:= bd 30cm:= nd 12:= (So lng dam)

lb 9m:= (Nhp khung trung bnh)

+ Tiet dien, so lng vach t 20cm:=


48/60

H

s:= 0.621=

+ He so

1 sinh ( )+( )

cosh ( ):= 1.176=

2 - Xac nh noi lc va chuyen v trong he

+ Mo -men trong toan bo he vach cng c xac nh theo cong thc:

zmin 0m:= zmax H:= n 20:= (So tang)


n+, zmax..:=

z( )z

H:= z( )

z

s:=

- Vach

Mv ,( )p H

2

2

1

21 ( )

2 2 1( ) 1

21 cosh ( ) sinh ( )+( )

10

3:=

Qv ,( )p H

21 ( ) 2 1( ) cosh ( )+

sinh ( )

:=

- Khung

B0 Eb I0:= B0 2.651 109

kgm2

=

+ He so o cng :

1B

B0

+:= 1.149=

+ Tong o cng n v s cua cac cot khung trong 01 tang

s ncEb Ic

ht:= s 5.399 10

5 kgm=

+ Tong o cng n v r cua cac dam trong 01 tang

r nd

Eb bdhd

3

12

lb:= r 1.608 10

4 kgm=

+ o cng chong trt cua khung

A12

ht1

s

1

r+

:= A 5.679 104

kg=

+ He so s:

sB

A 2:= s 106.337m=

+ ac trng chong uon khi x = H


49/60

Qk ,( )p H

21

sinh ( )+ cosh ( )

:=

Nk ,( )p H

2

2 lb( ) 2

1

2

1 ( )2

1

2

1 cosh ( ) sinh ( )( )+

:=

+ Chuyen v cua he ke cau

y ,( )p s

4

B 2

2

2 cosh ( )+ sinh ( )

4

22 1( )

2

2

3

3

4

12+

+

10:=

200 0 200 400 600 8000

12.5

25

37.5

5062.5

75

87.5

100

z

Qv z( ) z( ),( )

10 2 6 14 22 300

12.5

25

37.5

5062.5

75

87.5

100

z

Mv z( ) z( ),( )

0 8 16 24 32 400

12.5

25

37.5

50

62.5

7587.5

100

z

Qk z( ) z( ),( )

0 0.6 1.2 1.8 2.4 30

12.5

25

37.5

50

62.5

7587.5

100

z

y z( ) z( ),( )

6000 4400 2800 1200 400 20000

12.5

25

37.5

50

62.5

75

87.5

100

z

Nk z( ) z( ),( )


50/60

z

0

3.3

6.6

9.9

13.2

16.5

19.8

23.1

26.4

29.7

33

36.3

39.6

42.9

46.2

49.5

52.8

56.1

59.4

62.7

66

m

= z( )

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

0.55

0.6

0.65

0.7

0.75

0.8

0.85

0.9

0.95

1

= z( )

0

0.031

0.062

0.093

0.124

0.155

0.186

0.217

0.248

0.279

0.31

0.341

0.372

0.403

0.434

0.466

0.497

0.528

0.559

0.59

0.621

= Mv z( ) z( ),( )

23.069

20.675

18.419

16.299

14.314

12.463

10.743

9.154

7.695

6.364

5.16

4.084

3.133

2.308

1.607

1.03

0.578

0.248

0.042

-0.04

-1.07610 -14

kgm

s2A

= Qv z( ) z( ),( )

746.46

704.413

662.879

621.827

581.225

541.044

501.254

461.824

422.726

383.931

345.41

307.134

269.076

231.208

193.501

155.928

118.462

81.075

43.74

6.43

-30.883

T

=Qk z( ) z( ),( )

0

4.724

8.935

12.664

15.943

18.801

21.268

23.375

25.15

26.622

27.82

28.773

29.508

30.053

30.437

30.687

30.83

30.894

30.906

30.893

30.883

T

=Nk z( ) z( ),( )

86.926

-120.961

-329.865

-539.897

-751.171

-963.808

-1.178103

-1.394103

-1.611103

-1.831103

-2.052103

-2.276103

-2.502103

-2.731103

-2.962103

-3.196103

-3.434103

-3.675103

-3.919103

-4.168103

-4.42103

T

=y z( ) z( ),( )

0

0.014

0.055

0.12

0.205

0.309

0.429

0.563

0.709

0.864

1.028

1.198

1.374

1.553

1.736

1.92

2.106

2.293

2.48

2.667

2.855

m

s2A


51/60


52/60


53/60

y ,( )p s2

4

B 2

2


4

22 1( )

2

2

3

3

4

12+

+

10:=

+ Chuyen v cua he ket cau (cm):

Nk ,( )p H

2

2 lb( ) 2

1

21 ( )

2

1

21 cosh ( ) sinh ( )( )+

:=

Qk ,( )p H

21

sinh ( )+ cosh ( )

:=

- Khung

Qvl ,( ) Qv ,( )Ivl

2 Iv Ivl+( ):=

Mvl ,( ) Mv ,( )Ivl

2 Iv Ivl+( ):=Trong 01 vach cng co lo ca:

Qv1 ,( ) Qv ,( )

Iv

2 Iv Ivl+( ):=

Mv1 ,( ) Mv ,( )Iv

2 Iv Ivl+( ):=Trong 01 vach cng ac:

Mo men va lc cat phan bo vao vach cng theo ty le o cng

Qv ,( )p H

21 ( ) 2 1( ) cosh ( )+

sinh ( )

:=

Mv ,( )p H

2

2

1

21 ( )

2 2 1( ) 1

21 cosh ( ) sinh ( )+( )

10

3:=

- Vach

z( )z

s2:= z( )

z

H:=


n+, zmax..:=

(So tang)n 20:=zmax H:=zmin 0m:=



4.005=1 sinh ( )+( )

cosh ( ):=

+ He so

3.971=H

s2:=


54/60

50 10 70 130 190 2500

8.75

17.5

26.25

35

43.75

52.5

61.25

70

z

z

z

Qv1 z( ) z( ),( ) Qvl z( ) z( ),( ), Qk z( ) z( ),( ),

0.5 0.4 1.3 2.2 3.1 40

10

20

30

40

50

60

70

80

z

z

Mv1 z( ) z( ),( ) Mvl z( ) z( ),( ),


55/60

3 .104

2.3 .104

1.6 .104

9000 2000 50000

10

20

30

40

50

60

70

80

z

Nk z( ) z( ),( )

0 0.24 0.48 0.72 0.96 1.2

0

10

20

30

40

50

60

70

80

z

y z( ) z( ),( )


56/60

+ Tiet dien, so lng vach -khung t1 18cm:= Lv1 1100cm:= nv1 3:=

+ Vat lieu: Eb 240000kg

cm2

:=

+ Tai trong ngang tnh toan phan bo eu tng ng tac dung len cong trnh

p 9.778T

m:=

---------------------------------------------------------------------------------------------------------------------

1- Xac nh cac ai lng cua ket cau

1.1 Xac nh B: o cng he oi vi truc i qua trong tam cua tng cau kien

+ Mo -men quan tnh cot:

Ic bc hc3

12:= Ic 0.011m4=

+ Mo -men quan tnh cua vach cng ac

Iv tLv

3

12:= Iv1 t1

Lv13

12:= Iv 61.44m

4=

+ Tong o cng chong uon cua moi he chu lc oi vi truc i qua trong tam riengcua tng he:

B Eb nvIv nv1 Iv1+ ncIc+( ):= B 4.39 1011

kgm2

=

1.2 Xac nh B0: o cng he oi vi truc i qua trong tam cua ca he:

+ Do he khong oi xng, ta xac nh trong tam cua he (theo phng yi):

F nc hc bc( ) nv1 t1 Lv1( )+ nv t Lv( )+:=

V du 3. Cho cong trnh co mat bang ket cau nh hnh ve:

Lx Lx Lx Lx Lx Lx

L

y

Ly=8.0m

11.0m

5.0m

16.0m

56.0m

LxLx=8.0m

Cac d kien:

+ Mat bang, chieu cao: Lx 64m:= Ly 16m:= H 57.6m:= ht 3.6m:=

YLy

2:=

+ Tiet dien, so lng cot: bc 60cm:= hc 60cm:= nc 15:=

+ Tiet dien, so lng Dam hd 80cm:= bd 40cm:= nd 8:= (So lng dam)

lb 8m:= (Nhp khung trung bnh)

+ Tiet dien, so lng vach t 18cm:= Lv 1600cm:= nv 2:=


57/60

s 8.64 107

kgm=

+ Tong o cng n v r cua cac dam trong 01 tang

r nd

Eb bdhd

3

12

lb:= r 4.096 10

7 kgm=

+ o cng chong trt cua khung thuan tuy A1

A112

ht

1

s

1

r+

:= A1 9.262 107

kg=

b) - Khung hon hp

Dam trong khung hon hp bd_hh 18cm:= hd_hh 35cm:=

Ld_hh 5m:=

Momen quan tnh dam khung: Id_hh bd_hhhd_hh

3

12:=

id -o cng n v dam, cot trong khung hon hp

idEb Id_hh

Ld_hh:= id 3.087 10

5 kgm=

yC

nv1 bc hc Y nv1 t1 Lv1 YLv1

2

F:= yC 0.363 m=

yC1 2.5m yC+:=

+ Mo -men quan tnh oi vi trong tam cua he:

I0c 7 Ic bc hc Y yC( )2

+ 4 Ic bc hc yC( )2

++ 4 Ic bc hc Y yC+( )2

++:=

I0 I0c nv Iv Lv t yC2

+( )+ nv1 Iv1 t1 Lv1 yC1( )2++:=I0 471.247m

4=

+ Tong o cng chong uon cua moi he chu lc oi vi trong tam cua toan he:

B0 Eb I0:= B0 1.131 1012

kgm2

=

1.3 He so o cng:

1B

B0+:= 1.178=

1.4 Xac nh o cng chong trt cua he A (khung thuan tuy -A1 va khung vach -A2):

a) - Khung thuan tuy

+ Tong o cng n v s cua cac cot khung thuan tuy trong 01 tang

s 12Eb Ic

ht:=


58/60

1.004=

+ He so

1 sinh ( )+( )

cosh ( ):= 1.412=



zmin 0m:= zmax H:= n 16:= (So tang)


n+, zmax..:=

z( )z

H:= z( )

z

s2:=

- Vach lien khung

Mv ,( )p H

2

2

1

21 ( )

2 2 1( ) 1

21 cosh ( ) sinh ( )+( )

10

3:=

Qv ,( )p H

21 ( ) 2 1( ) cosh ( )+

sinh ( )

:=

- Khung

x

y

5.5m

5.5m

yC

yC1

11.0

m

-

icnv1 Eb Ic

ht:= ic 2.16 10

7 kgm=

Z0Lv1

2:=

0Z0

Ld_hh:= 0 1.1=

A23 id 1 0+( ) id 1 0+( ) 6 ic 1 2 0+( )+[ ]

ht id 3 ic+( ):=

A2 3.446 106

kg=

Vay:

A A1 A2+:= A 9.607 107 kg=

1.5 Xac nh he so s2, va :

+ He so s2:

s2B

A 2:= s2 57.377 m=

+ ac trng chong uon khi x = H

H

s2:=


59/60

Qk ,( )p H

21

sinh ( )+ cosh ( )

:=

Nk ,( )p H

2

2 lb( ) 2

1

21 ( )

2

1

21 cosh ( ) sinh ( )( )+

:=

+ Chuyen v cua he ket cau (cm):

y ,( )p s2

4

B 2

2


4

22 1( )

2

2

3

3

4

12+

+

10

2:=

200 40 120 280 440 6000

7.5

15

22.5

3037.5

45

52.5

60

z

Qv z( ) z( ),( )

5 1 3 7 11 150

7.5

15

22.5

3037.5

45

52.5

60

z

Mv z( ) z( ),( )

0 12 24 36 48 600

7.5

15

22.5

30

37.5

45

52.5

60

z

Qk z( ) z( ),( )0 6 .10

40.00120.00180.00240.003

0

7.5

15

22.5

30

37.5

45

52.5

60

z

y z( ) z( ),( )

4000 3000 2000 1000 0 1000

0

7.5

15

22.5

30

37.5

45

52.5

60

z

Nk z( ) z( ),( )


60/60

z

0

3.6

7.2

10.8

14.4

18

21.6

25.2

28.8

32.4

36

39.6

43.2

46.8

50.4

54

57.6

m

= z( )

0

0.063

0.125

0.188

0.25

0.313

0.375

0.438

0.5

0.563

0.625

0.688

0.75

0.813

0.875

0.938

1

= z( )

0

0.063

0.125

0.188

0.251

0.314

0.376

0.439

0.502

0.565

0.627

0.69

0.753

0.816

0.878

0.941

1.004

= Mv z( ) z( ),( )

14.097

12.151

10.363

8.73

7.246

5.907

4.709

3.65

2.727

1.936

1.277

0.746

0.344

0.068

-0.081

-0.103

5.14910 -15

kgm

s2A

= Qv z( ) z( ),( )

563.213

518.332

474.911

432.817

391.924

352.109

313.254

275.246

237.972

201.325

165.2

129.492

94.101

58.925

23.866

-11.178

-46.304

T

=Qk z( ) z( ),( )

0

9.68

17.9

24.793

30.486

35.1

38.754

41.562

43.635

45.081

46.005

46.512

46.702

46.677

46.536

46.379

46.304

T

=Nk z( ) z( ),( )

132.71

-51.099

-237.639

-427.318

-620.581

-817.907

-1.02103

-1.227103

-1.44103

-1.659103

-1.885103

-2.119103

-2.362103

-2.614103

-2.877103

-3.151103

-3.437103

T

=y z( ) z( ),( )

0

1.98310 -5

7.55610 -5

1.61910 -4

2.74110 -4

4.07710 -4

5.58810 -4

7.23810 -4

8.99610 -4

1.08310 -3

1.27310 -3

1.46710 -3

1.66210 -3

1.85910 -3

2.05610 -3

2.25310 -3

2.44910 -3

m

s2A

=

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Nha Nhieu Tang