1c

B

NG DUNG ETABS TRONG THIET KE KETCAU VACH CNG NHA CAO TANG

NOTES: Vi cac cong trnh nha cao tang phan t vach la khong the thieu.Conhieu quan iem thiet ke vach.Nhng xin c trnh bay quan iem tnhvach nh sau: Xem vach la cau kien cot chu nen uo n va tnh vach nh bnhthng.Ket hp vi Etabs e thiet ke va co ieu chnh e bo tr thep chohp ly.- Vach co nhieu dang nhng chung ta nen a ve dang vach co hnh ch nhate de dang tnh toan.Nh sau:

XNz

Mx Y

H/5 H/5H

1 Thep cau tao a=200 1'

Vic tnh toan thep chu yeu trong 2 vu ng 1 va 1.Thep trong vung gia cat theo cau tao.Thng la 16a200(>12).Bai toan at ra : Sau khi ngis dung xuat ra c noi lc trong vach( Etabs) gom momen Mx va lc docNz.Chung ta li dung Etabs thiet ke t hep cho chung ta(chieu cao vach chnhla chieu cao tang nha).

Viec thiet ke ket cau be tong cot thep theo tieu chuan TCVN rat khokhan. Ket qua oi khi t chnh xac. Sau ay la mot cach mi c e xuat,ket qua cho tng oi kha quan: S dung tieu chuan Canada CSA -A23.3-94lam nen tang, sau o khai bao cac thong so cho phu hp vi TCVN.

Cac thong so ieu chnh e Etabs thiet ke theo TCVNGia tr f tng ng vi Mac Be tong theo TCVN

2MacBetong 200 250 300 350 400 500Rn(kg/cm2) 90 110 130 155 170 215f'c (T/m2) 1822 2244 2673 3219 3552 4579

Gia tr fy tng ng vi loai cot thep theo TCVNLoi thep AI AII AIII CI CII CIII

Ra(kg/cm2)

2100 2700 3600 2000 2600 3400fy (T/m2) 24701 31765 42353 23530 30589 40000

Gia tr k tng ng vi Mac be tong va ham lng cot thepGia s ham lng cot thep ga thiet la gt=1,5%

Mac BT 200 250 300 350 400 500He so k 0.67 0.69 0.71 0.72 0.73 0.75

V du cu theCho vach co chieu dai vach H=4.3 m, Chieu rong vach B=0.25 m,Chieucao tang nha =3.2 m, Vach chu lc doc Nz=1050(T), Momen uon quayquanh phng chu lc Mx(hoac My-tuy cong trnh->cac gia tr nay cxuat ra t Etabs (phng dai H).Vach lam bang Be tong M300,thep chulc CII, thep ai CI

Trnh t tnh toan nh sau:1.Khi ong chng trnh Etabs (Sap2000 cung lam c-nhng xinphep trnh bay ay cach lam Etabs)- Click up chuot vao bieu t ng Etabs tren man hnh

Hoac nhan Start/All programs/Computer and Structure/Etabs 9/Etabs

32.oi n v s du ng goc di ben phai man hnh qua n v SI: T ,m(he nv mac nh cua chng tr nh la Kip-In3.Click vao Menu File -> New Model

Hop thoai New Model Initialization xuat hien

Click chon No4.Nhap cac gia tr trong Hop thoai Buiding Plan Grid System and Story DataDefinition nh sau:

5.Click OK e thoat khoi hop thoai Buiding Plan Grid System and Story DataDefinition6.Khai bao vat lieu cho vachClick Define -> Material Properties

4Hop thoai Define xuat hien

- Click chon CONC( Vat lieu Be tong)- Click Modify/Show Material

Hop thoai Material Property Data xuat hien

Nhap cac thong so nh tren( Tra t bang a cho) Click OK e ket thuc vieckhai bao vat lieu7.Khai bao tiet dien cho vach ( luc nay xem nh cot)Click Define -> Frame Sections

Hop thoai Define Frame Properties xuat hien

5Chon Add RectangularHop thoai Rectangular Section xuat hien

Nhap cac gia tr nh trenClick 2 lan OK e ket thuc khai bao tiet dien

68.Khai bao trng hp tai trongClick Define -> Static Loads Case

Hop thoai Define Static Loads Case Names xuat hien

Nhap cac gia tr nh tren ( ta xet noi lc trong vach nh tre n ch la trnghp TT+HT-chng trnh t tnh tai trong ban than cho ta n en nhap gia tr oSelf Weight Muliplier la 1.1( 1.1 chnh la he so vt tai oi vi trng hp TT)9.Khai bao to hp tai trongClick Define -> Loads Combinations

Click Add New Combo

7- Click 2 lan OK10.Gan tiet dien

Chu y: Gan cot(vach) ch gan c tren mat bang do o chung ta chuyenqua mat bang e gan Click chon bieu tng tren vachon Story1( elev: chon mat ng)- Click vao bieu tng nh ben di trong thanh cong cu

- Chon tiet dien can gan do ng Properties la COT25430( a khai bao bentren)

8- Click nut tai v tr muon gac co t( vach) hoac re chuot tao vung baoKet qua sau khi gan nh sau:

11.Gan ieu kien bien- Click chon goi nh sau

9- Click Menu Assign -> Joint/Point -> Restraint

- Click chon bieu tng ngam nh tren12.Gan tai trong- Click Chon nut tai au tren cua cot- Click Menu Assign -> Joint/Point Loads -> Forces

Hop thoai Point Forces xuat hien

Gan trng hp Tnh tai( TT) lc doc tac dung len cot( vach) nh tren

10

Gan trng hp Hoat tai(HT) Momen tac dung len cot(vach) nh tren13.Gan bac t doClick Menu Assign -> Analyze -> Set Analysis Options

- Click vao bieu tng XZ Plane- Click OK

11

14.Chay chng trnh- Click Menu Assign -> Analyze -> Run Analysis- at ten muon lu File va Click chon Run

THIET KE THEPSau khi Run khong bao loi chung ta bat au tien hanh thi et lap cho chngtrnh t thiet ke thep1.Click Options -> Preferences -> Concrete Frame Design

Hop thoai Concrete Frame Design Preferences xuat hien

- Click chon CSA-A23.3-94 (tieu chuan Canada)- Click OK2. Click Design -> Concrete Frame Design -> Select Design Combos

- S dung nut Remove( Bo) va Show( Chon) e chon to hp thiet ke la tohp BAO- Click OK

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3.Chon phan t cot tren4.Click Design -> Concrete Frame Design -> View/Revise Overwrites

Thay oi so lieu nh tren(cho phu hp vi TCVN)- Click OK5.Run mot lan na6. Click Design -> Concrete Frame Design -> Star Design/Check of StructureLuc nay tren cua so lam viec se xuat hien so tiet dien thep thiet ke.e dekiem soat theo TCVN ta a n v lai ve dang Ton -cm

13

250Nh vay theo Etabs tnh toan lng cot thep can cho cot tren la 151. 543cm2(Tong lng thep tren mat cat ngang)Ta tien hanh ieu chnh nh sau e chuyen thanh thep trong vachLng thep tnh ra trong vach se c bo tr cho 2 vung (H/5, H/5+(1->50cm) 2 bien, con phan gia (3H/5, 3H/5-2.50(1-> 50cm) c at theo cautao la thep 16a200.1-50 cm la gia tr dao o ng e viec bo tr sao cho vungat thep cho ra mot gia tr tng oi chan, am bao ieu kie n thi congBo tr thep nh sau:H/5=4.3/5=0.86m->0.9m=900 mmLng cot thep can =151.543 cm2/2=75.8 cm2Chon thep 22,so thanh thep can la 75.8/3.8=19.95 thanhSo thanh thep vung bien nen chon l a so le.Vay so thanh thep c chon botr la:21.Khoang cach gia 2 thanh thep a=900/[(21-1)x2]=100Vung gia =4.3-2x0.9=2.5m=2500 mmChon thep cau tao la 16a200

22a100 16a200 16a100 16a200 22a100

22a100 16a200 16a1004300

16a200 22a100

NOTES: Viec tnh toan va at cot thep nh tren ch la mot e xuat.Cac bannen kiem tra vi cac cong trnh trong thc te.e rut ra kinh nghiem va kiemtra e xuat tren co ung hay khong.Ve pha ca nhan toi th viec tnh toan vabo tr thep trong vach nh tren la ung va thien ve an toan, tham ch la d.