giao_trinh_sap2000-fem.pdf

SAP2000

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2 Phn mm phn tch kt cu SAP2000

2.1. Gii thiu phn mm SAP2000 B phn mm SAP2000 c gio s Edward L. Wilson v cc cng s (i hc

California, Berkeley, M) nghin cu lp ra da trn cc phng php s v phng php phn t hu hn trong c hc. Ban u, phn mm ny ch l cc chng trnh n l, chy trn cc my tnh ln, phc v cho cng tc nghin cu l chnh.

Phin bn u tin ca chng trnh mang tn SAP (Structural Analysis Program) ra i vo nm 1970. Cc phin bn k tip l SAP3, SAP-IV B phn mm mang tnh thng mi u tin l SAP80 (SAP-VI), c pht trin bi cng ty Computer & Structure Inc CSI.

SAP2000 (SAP-VII) l mt bc t ph ca h phn mm SAP. SAP2000 tch hp cc chc nng phn tch v thit k kt cu thnh mt. Ngoi ra, SAP2000 cn c b sung thm cc loi phn t mu v kh nng phn tch kt cu phi tuyn (nonlinear). Ton b cc qu trnh t xy dng m hnh kt cu (pre-processing), thc hin phn tch (processing) n biu din kt qu (post-processing) u c giao din ha trc quan (visual graphics) d s dng. Do vy phn mm SAP2000 hin nay ang c s dng rng ri trong nghin cu cng nh tnh ton thit k cng trnh. 2.2. Cc phin bn chnh ca SAP2000

SAP2000 V7.42 c cc phin bn sau: + Phin bn phi tuyn (Nonlinear Version) c kh nng phn tch cc bi ton tnh,

ng lc hc, phi tuyn, thit k kt cu b tng, kt cu thp vi bn loi phn t mu khc nhau, s lng nt ca kt cu l khng gii hn.

+ Phin bn chun (Standard Version) ch gii quyt c cc bi ton c s lng nt ti a khong 1500 nt, khng phn tch c bi ton phi tuyn.

+ Phin bn nng cao (Plus Version) c kh nng tng t nh bn Nonlinear, nhng khng phn tch c bi ton phi tuyn.

+ Phin bn dng cho hc tp (Education Version) kh nng tng t nh bn phi tuyn, nhng hn ch s nt ti a l 100 nt.

Vi phin bn SAP2000 V10 hin nay, c 03 phin bn: + Phin bn BASIC c cc tnh nng tng t nh cc phin bn trc nhng c

ci tin phng php gii h phng trnh i s tuyn tnh ca FEM gip chng trnh chy nhanh hn, b sung thm cc phn t ch chu ko, phn t thanh cng ng sut trc (post-tensioned tendon), phn t shell c chnh xc cao hn, kh nng phn tch ng lc nhiu trng hp t hp trong cng mt ln chy

+ Phin bn PLUS tng t nh BASIC nhng c b sung kh nng phn tch v cu, phn tch min tn s, ph thi gian, ti trng ng t

SAP2000


+ Phin bn ADVANCE b sung thm cc phn t phi tuyn, phn tch ph thi gian phi tuyn bng phng php chng cht m hnh hoc tch phn trc tip, phn tch bi ton n nh (buckling analysis) 2.3. Kh nng phn tch kt cu ca SAP2000

Trong SAP2000 V7.42 ngi dng c th m t nhiu loi ti trng khc nhau nh lc tp trung, lc phn b u hoc hnh thang, ti trng do nhit , ti trng do ph gia tc, ti trng iu ha v ti trng di ng

Cc loi bi ton kt cu m SAP2000 c th thc hin gm c: + Bi ton phn tch tnh (static analysis) + Bi ton tnh tn s dao ng ring v cc dng dao ng (modal analysis) + Bi ton tnh p ng c lc hc (response analysis) vi ti trng ngoi thay i

theo thi gian hay ph gia tc. 2.4. Ci t phn mm SAP2000 (7.42)

Phn mm SAP2000 chy trn h iu hnh WINDOWS 95/98/NT. Ngoi ra phin bn Plus v Nonlinear c kh nng chy trn mng WINDOWS NT (v3.5) v NETWARE theo m hnh Client/Server. ci t trn mng cn c thm cc driver cho mng km theo phn mm.

Yu cu h thng: + H iu hnh WINDOWS 95/98/NT + B nh RAM ti thiu 12MB (nn c16MB) + a cng cn trng ti thiu 10MB (nn c 40MB) + B x l (CPU): ti thiu 486DX-4 (nn c Pentium 100) + Card ha: VGA hay SVGA + My in, my v. Ngi dng ci t phn mm SAP2000 theo hng dn ca nh sn xut.

2.5. Cu trc ca SAP2000 Chng trnh c cu trc di dng file thc thi chng trnh (Sap2000.exe), n

s ln lt gi cc tp tin v hm ph tr (*.DLL) trong qu trnh thc hin. File d liu ca SAP2000 c phn m rng l *.SDB v *.S2K. i vi file S2K,

ngi dng c th dng mt phn mm son tho hiu chnh. Cc file kt qu bao gm *.EKO cha thng tin v d liu nhp vo, file .OUT cha

tt c cc kt qu c xut ra. Cc tp tin dng .JOB lu d liu ca SAP2000 di dng nh phn. Cc tp tin .DXF lu d liu m hnh kt cu dng ca AUTOCAD. SAP2000 h tr mi trng lm vic tng t nh mt phn mm CAD. Ton b

qu trnh xy dng m hnh c thc hin bng cc i tng im, ng thng, tam gic Sau khi cc i tng ny c gn cc c trng c l ring th chng tr thnh cc phn t ca kt cu1.

1 i vi SAP90 tr v trc, ngi dng phi to ra cc loi nt, phn t sau ni chng li vi nhau thnh m

hnh kt cu. Vic lm ny gy tn km nhiu thi gian khai bo d liu nhp vo.

SAP2000


2.6. Trnh t phn tch kt cu bng SAP2000 Khi thc hin phn tch mt bi ton kt cu, ngi dng thng thc hin theo

trnh t cc bc sau y:

Xy dng m hnh kt cu

nh ngha cc nhm vt liu

Khai bo cc c trng hnh hc v gn cho phn t

nh ngha cc trng hp ti v gn ti trng cho phn t

nh ngha cc t hp ti trng

Khai bo cc iu kin bin

Chn cc thng s cho qu trnh gii

Thc hin gii bi ton

Xem biu din kt qu v xut kt qu

Dng cc cng c xy dng hnh hc hoc ly t th vin kt cu mu (Templates)

Define Materials

Define Frame section Define Shell section Define Nllink properties

Define Static loadcase Assign

Define Load combination

Assign Restraints

Analyze Set Options

Analyze Run

Display Show

Thit k kt cu Design Steel/concrete

Step 1

Step 2

Step 3

Step 4

Step 5

Step 6

Step 7

Step 8

Step 9

Step 10

SAP2000


3 Phn tch kt cu vi SAP2000

3.1. Bi thc hnh s 1 - H dn 3.1.1. Cc quy c c bn

SAP2000 s dng ma trn cng ca phn t thanh chu lc tng qut (frame element) cho cc kt cu dng thanh. i vi thanh dn, do ch c thnh phn lc dc xut hin trong cc thanh v chu bin dng dc trc nn ta ch cn khai bo duy nht gi tr din tch tit din ngang (cross section area), cc s liu khc ta s gn bng 0.

Cc ti trng tc dng ln thanh dn ch tc dng ti nt, do ta ch cn khai bo cc ti tp trung:

Assign Joint static loads Forces Ch , khi tnh ton vi SAP2000, h s ti

trng bn thn ca kt cu s mc nh l 1 v chng trnh s t ng tnh ton gi tr ti trng bn thn kt cu. iu ny dn n vic xut hin cc mmen un v lc ct trong thanh dn. Thng thng vi h dn, ngi ta b qua ti trng bn thn, hoc quy i ti trng tng ng v cc mt dn. loi b iu ny, chng ta c th thc hin 02 cch sau y: Cch 1: Gn cc s liu v trng lng ca kt cu bng 0:

Define Materials Add New Material Cch 2: Gn h s ti trng bn thn (Self Weight Multiplier) bng 0:

Define Static load cases

SAP2000


Nh phn tch chng 1, phn t thanh dn phng l mt phn t 2 nt, chu bin dng dc trc. Do vy, khi xt trong h ta tng th OXZ, mi nt ch c 02 bc t do (Degree of Freedom DOF) l cc chuyn v thng UX v UZ theo 2 trc ta . Nu l dn khng gian th mi nt s c 03 bc t do l UX, UY v UZ. Nh vy trc khi tin hnh gii bi ton h dn ta phi kha cc bc t do khng cn thit.

Nu l dn phng trong mt phng OXZ, ta s nh du cc bc t do UX, UZ Analyze Set Options

Nu l dn khng gian, ta s nh du cc bc t do UX, UY, UZ Analyze Set Options

3.1.2. Cc bi tp thc hnh Bi tp 1 P = 10KN, a = 5m, E = 2,1.104 KN/cm2. Cc thanh ng v ngang c tit din l F1 = 10cm2. Cc thanh xin c tit din F2 = 7,071 cm2. H s Poisson = 0,3.

Trnh t thc hin: Bc 1 : M t hnh hc Chn h n v KN-cm, File > New Model From Template > [Vertical Truss]

Lu : Click [ ] mc Restraints nh hnh minh ha

SAP2000


Bc 2 : Khai bo c trng vt liu Define > Materials > [ Add New Materials ]

- Material Name : THEP - Mass per unit Volume : 0 KN - Weight per unit Volume : 0 KN - Modulus of Elasticity: 2.1.104 KN/cm2 - Poissons Ratio : 0.3 - Coeff of Thermal Expansion : 0

Bc 3 : Khai bo c trng hnh hc nh ngha c trng hnh hc cho phn

t thanh t menu ta chn: Define > Frame Sections >

T hp danh sch th hai trong mc Click to chn [Add General].

Tt c cc phn t trong kt cu c coi nh l phn t thanh dn, do vy ch cn khai bo gi tr din tch mt ct ngang ca tit din, cc thng s cn li khai bo bng zero.

Section name : tn ca tit din, tn ny s c thay i trong bng i thoi k tip, sau khi hon tt cc khai bo c trng hnh hc.Click OK ng hp thoi v sa li tn c trng hnh hc, ng thi chn vt liu l THEP.

Hai hnh trn minh ho cho khai bo loi tit din F1. Lp li qu trnh khai bo d liu trn cho loi tit din F2 . Sau khi hon tt, bng i thoi nh ngha c trng hnh hc s cho kt qu nh hnh sau:

SAP2000


Bc 4 : Gn c trng hnh hc vt liu cho phn t - Chn cc thanh ng v ngang bng cch click chut vo tng thanh hay dng

mt ca s qut qua cc thanh, gn loi c trng hnh hc F1 cho cc phn t ny. T menu ta chn : Assign > Frame > Sections > chn F1 > click phm OK xc nhn.

- Lm tng t cho cc thanh xin. Bc 5 : Gn ti trng tp trung ti nt Chn nt cn gn ti tp trung, t menu chn: Assign > Joint Static Loads > Forces

Force Global Z : -10 Bc 6 : Khai bo iu kin bin

Chn hai nt cn gn iu kin bin, t menu chn Assign > Joint > Restrains > click biu tng khp (nt th hai t tri sang) hoc click vo 3 Translation 1,2 v 3. Bc 7 :Thc hin gii

- Chn bc t do cho nt Analyze > Set Options > Click vo 2 [v] UX va [v] UZ nh hnh sau.

- Lu bi ton v thc hin gii (F5)

-------------------------------------------------------------------------------------------------------- Bi tp 2 P = 15KN, a = 3m, E = 2,1.104 KN/cm2. Cc thanh ng c tit din l F1 = 10cm2. Cc thanh xin c tit din F2 = 15 cm2. Cc thanh ngang c tit din F3 = 20cm2

H s Poisson = 0,3.

Phn tch s b: kt cu i xng trc vi nhau, do vy ta ch cn v mt na kt cu sau ly i xng trc

SAP2000


Trnh t thc hin: Bc 1 : M t hnh hc

- Chn h n v KN-cm, File > New Model > Cartesian X Y Z Number of Grid Spaces 4 0 2 Grid Spacing 300 - 300

- Chuyn v mt phng XZ. - Chn phm Draw Frame Element

v cc phn t thanh . - Do kt cu c tnh i xng, ta ch cn v

phn na kt cu , kt qu sau khi v :

- Chn tt c cc phn t mi v, t menu Edit > Replicate > [Mirror]

Click [] YZ Plane ; X = 0 V thm phn t thanh trn cng c kt cu hon chnh. Bc 2 : Khai bo c trng vt liu v c trng hnh hc Khai bo c trng vt liu:

Define > Materials > [Add New Materials] Material Name : THEP Mass per unit Volume : 0 KN Weight per unit Volume : 0 KN Modulus of Elasticity : 2.1.104 KN/cm2 Poissons Ratio : 0.3 Coeff of Thermal Expansion : 0

Khai bo c trng hnh hc: Define > Frame Sections >

Lm tng t nh bi tp 1-1 c vt liu THEP v cc tit din F1, F2, F3.

SAP2000


Bc 3 : Gn c trng hnh hc vt liu cho phn t (lm tng t bi tp 1) Bc 4 : Gn ti trng tp trung ti nt (lm tng t bi tp 1), di y minh ho gn ti tp trung ti nt trn cng bn phi (chu lc ngang theo phng X l 2P v lc hng xung, ngc chiu trc Z l P). Chn nt cn gn ti tp trung , t menu chn

Assign > Joint Static Loads > Forces Force Global X : 30 Force Global Z : -15

Bc 5 : Khai bo iu kin bin - Gn lin kt khp cho nt bn tri

(xem bi tp 1-1). - Gn lin kt gi cho nt bn phi.

Chn nt cn gn iu kin bin, t menu chn Assign > Joint > Restrains > click biu tng khp

(nt th ba t tri sang) hoc click vo Translation 3.

Bc 6 :Thc hin gii - Chn bc t do cho nt Analyze >

Set Options > Click vo 2 [v] UX v [v] UZ.

- Lu bi ton v thc hin gii (F5). -------------------------------------------------------------------------------------------------------- Bi tp 3 Gii kt cu cn trc vi cc s liu sau: P = 100KN, a = 2m, E = 2,1.104 KN/cm2. Cc thanh ng c tit din l F1 = 50cm2, cc thanh xin c tit din F2 = 60 cm2. Cc thanh ngang c tit din F3 = 70cm2, H s Poisson = 0,3.

SAP2000



- Chn h n v KN-m, File > New Model > Cartesian X Y Z

Number of Grid Spaces 4 0 3 Grid Spacing 2 - 2

- Thm ng li cao Z=5m Draw > Edit Grid (shift F7) []: Direction Z; Z Location: 5 > Add Grid Line

Ta c thm ng li Z cao 5 m. Chn phm Draw Frame Element v cc phn t thanh . Kt qu sau khi v c nh hnh sau:

Bc 2: Khai bo v gn c trng vt liu Bc 3: Gn gi tr ti trng Bc 4: Gn iu kin bin Bc 5: Thc hin gii

- Chn bc t do cho nt Analyze > Set Options > Click vo 2 [v] UX v [v] UZ.

- Lu bi ton v thc hin gii (F5).

Hoc vien t thc hien

SAP2000


Bi tp 4 Phn tch h dn khng gian cu trc mng tinh th. H dn gm 4 vm n, mi vm c 17 khi chp t din c bn c kch thc 1,5 x 1,5x 1,5m nh hnh v bn di. Cao trnh nh vm l 18m. Thanh cnh trn v di ca dn lm bng thp P1, cc thanh xin thp P.75 (ly theo tiu chun trong tp tin Aisc.pro). Ti trng t ti cc nt cnh trn ca h l 50kgf. (Ch : gc xoay lin tip gia 2 chp l 4.4051960) Cho E = 2,1.108 KN/m2, v = 0,3.

Trnh t thc hien:

- To h li ta X, Y, Z . - V hnh chp con ngay ti gc ta . - nh ngha mt loi vt liu, v hai loi tit din hnh hc. - Gn cc c trng hnh hc, vt liu v ti trng tc dng ln nh hnh chp. - Di chuyn hnh chp n b tr nh vm. - Nhn bn hnh chp n to ra mt na cnh cung, ly i xng phn va

to c c mt cm cung. - Nhn bn mt vm thnh 4 vm. - Gn iu kin bin, khai bo cc bc t do hin c. - Thc hin gii.

Bc 1 : M t hnh hc - Chn h n v KN-m. - T Menu: File > New Model > Cartesian

X Y Z Number of Grid Spaces 2 2 1 Grid Spacing 0.75 0.75 1.5

1.5m

1.5m

P.75 P1

50kgf

Hnh chp c bn

SAP2000


Ve canh ben va canh ay Hnh chop c ban

- thun tin cho vic quan st v v hnh chp, gc nhn c thay i sao cho ph hp:

View > Set 3D View, cc gi tr cc thng s nh sau: Plan : 250; Elevation : 22; Aperture : 0 Bc 2 : V hnh chp Hnh chp c v trc tip bng cc phn t thanh, nh ca n hng xung di v t ti gc to . u tin mt cnh bn v mt cnh y c v trc, sau chng c pht sinh thnh bn c c hnh chp nh sau:

- Chn tt c cc i tng [Select All] - Chn Edit > Replicate > [Radial ]

+ Rotate about : Z axis + Increment data > Number: 3; Angle: 90

Bc 3 : nh ngha vt liu v hnh hc - Khai bo c trng vt liu:

Define > Materials > [ Add New Materials ] Material Name : THEP Type of Material : Isotropic Mass per unit Volume : 0 KN Weight per unit Volume : 0 KN Modulus of Elasticity : 2.1.108 KN/m2 Poissons Ratio : 0.3 Coeff of Thermal Expansion : 0

- Khai bo c trng hnh hc Tt c cc phn t ca kt cu u c tit din hnh vnh khn, chng c s hiu l P1 v P.75 (ly theo tiu chun AISC). D liu v tit din ngang ca tt c cc loi thp nh hnh c lu trong cc file c phn m rng l .PRO, i km vi chng trnh c cc file d liu tng ng vi tiu chun M AISC (AISC2.PRO), tiu chun Canada CISC (CISC.PRO) v tiu chun chu u (EURO.PRO). Khi s dng loi thp nh hnh c tit din thuc mt trong cc tiu chun trn th phi chn file d liu tng ng.

T Menu: Define > Frame Sections > [Click to] Import Pipe Chn file AISC3.pro , file ny c cha trong th mc ci t chng trnh.

SAP2000


Chn loi tit din P.75 v sau chn loi vt liu THEP tng ng. Sau khi chn mt loi tit din

chun t file c s d liu, chng trnh s t ng ly tt c cc thng s ca tit din , c ngha l tit din c tt c nhng gi tr ca cc c trng hnh hc nh din tch mt ct (A), din tch ct (A2, A3), moment qun tnh (I2,I3) Xut pht t yu cu ch cn xt n cng dc trc cho thanh dn, do ch duy nht gi tr din tch mt ct ngang (A) ca tit din l cn thit. Do vy, cc c trng khc cn c kh i, chng c gn gi tr bng khng. thc hin iu ny chng trnh SAP2000 h tr mt cng c c hit hu ch cho php nhn h s vi tng c trng hnh hc ca tit din, tng qut ta c th biu din nh sau:

modifiedProperty i PropertySec = a Sec

nhn h s cho cc c trng tit din, t bng i thoi hnh trn, ta click vo phm

gn Cross section (axial) Area = 1.0, cc thng s cn li cho bng zero. Vi cch lm tng t ta c c c trng hnh hc ca loi thp ng s P1 vi cc c trng hnh hc lin quan n un cng un, ct, xon c loi b. Bc 4 : Gn cc c trng hnh hc, ti trng - Chn cch thanh xin (dng ng thng ct qua cc thanh ) t menu chn Assign > Frames > Sections [Frame sections] > P.75 > OK - Dng ca s chn cc thanh mt y ca hnh chp

SAP2000


Assign > Frames > Sections [Frame sections] > P1 > OK - Chn cc nt mt y ca hnh chp (dng ca s) Chn h n v kgf-m. Gn ti trng tp trung ln cc nt

Assign > Joint Static Loads > Forces > [Force global Z]: -50.0 Tr li h n v trc kN-m. Bc 5: Di chuyn hnh chp c bn n v tr nh vm Chn tt c cc nt phn t [Select all] Edit > Move> [Delta Z]: 18 Bc 6: To mt vm cung

- Chn tt c nt - phn t, dng nt Previous selection [PS] hoc nt [All].

Edit > Replicate > Radial > Rotate about: Y Axis Number: 8

Angle: 4.4051960 - Phn bn tri ca mt cnh cung c th

c to bng nhiu cch khc nhau chng hn nh ly i xng 8 hnh chp bn phi qua mt phng YZ cch ny hi phc tp hoc lp li bc pht sinh hnh chp c bn vi gc xoay l - 4.4051960, trnh t thc hin theo cch ly i xng nh sau:

Chn hnh chp c bn, click phm [PS] (previous selection) To v gn cho nhm CHOPCB Assign > Group Name

Groups : CHOPCB > Add New Group Chn tt c cc i tng [All], sau loi tr cc i tng ca nhm CHOPCB: Select > Deselect > GroupsChn nhm CHOPCB > OK

SAP2000


Ly i xng Edit > Replicate > Mirror Mirror About : YZ line

Ordinate X =0 Sau khi ly i xng tng s hnh chp to c l 17, phn cn li l v cc thanh ni cc nh di hon thnh mt cnh cung. Phng ln hai hnh chp ngoi cng bn tri, v ni hai nh chp v gn loi tit din P1, sau chn phn t mi v, pht sinh thm 15 phn t na c c thanh ni tt c cc nh chp pha di. Bc 7: Nhn bn 1 vm thnh 4 vm v v cc thanh lin kt dc dn.

- Chn tt c mt vm cung [all] Edit > Replicate > Linear > Distance: 1.5 Number: 3

- V cc thanh lin kt dc dn. - khung ca s bn phi chn mt phng XY c cao bng vi to Z ca nt nh chp ngoi cng. View > Set 2D view > [Plane] > XY plane: 14.7011 - Phng ln mn hnh v v phn t thanh i qua 4 nt pha bn tri ca h dn, sau gn loi tit din P1 cho phn t mi v. Chia i tng mi v thnh 3 on nh bng lnh Edit > Divide Frames. Divide into: 3

Last/First ratio: 1

SAP2000


Kt qu c nh hnh sau

- Chn 3 phn t mi chia ri pht sinh chng thm 16 ln c c ton b thanh dc mt di ca dn, ch du ca gc xoay.

Edit > Replicate > Radial > Rotate about: YAxis Number: 8,

Angle: 4.4051960 Bc 8: p t iu kin bin v thc hin gii

- Chn bn nt ti bn gc ca dn (mt phng XY@Z=14.7011) Assign > Joint > Restraint > [x] Translation 1, 2 ,3

- Khai bo cc bc t do hin hu: Analyze > Set Analysis Options > Avaiable DOFs > click vo Space Truss hoc nh du vo cc Ux, Uy, Uz xc nhn ton b cc nt ca kt cu ch c 3 bc t do chuyn v thng, cc cn li trng.

- Thc hin gii: Analyze > Run (F5)

SAP2000


Bi tp 5 Gii kt cu thp truyn hnh bng h dn thp vi cc s liu sau: Cc thanh chng F1=20cm2, cc thanh ging F2 = 6cm2. cc cao trnh 0m, 5m, 10m, 15m, 20m u b tr cc h ging ngang, cc mt bn u b tr h ging xin. Kch thc v ti trng ti cc tng thp nh sau: + Chn (ct +0.0m) : a=5m + Tng 1 (ct +5m): a=4m, P=10KN + Tng 2 (ct +10m): a=3m, P=15KN + Tng 3 (ct +15m): a=2m, P=20KN + Tng 4 (ct +20m): a=1m, P=30KN


- Chn h n v KN-m, File > New Model > Cartesian X Y Z Number of Grid Spaces 10 10 4 Grid Spacing 0.5 0.5 5

- Chn mt phng XY, s dng hai phm Up One Gridline v Down One Gridline di chuyn n cc mt phng li (mt phng XY ti cc cao Z

khc nhau) v cc thanh ging ngang. Kt qu sau khi v cc thanh ging ngang c 4 tng

+5m

+10m

+15m

+20m

+0.0m

P

P P

P

a

a

Mt bng tng 1-2-3-4

SAP2000


- Chn mt phng XY cao Z = 0, chn phm Draw Special Joint to 4 nt chn nh hnh sau.

- V hai thanh chng v cc thanh ging xin cho mt mt bn bt k nh hnh sau:

- Khai bo c trng vt liu v hnh hc (lm tng t nh cc bi tp trn).

- Gn c trng hnh hc cho cc phn t va v.

- Chn hai thanh chng v cc thanh ging xin (1 mt bn), pht sinh thm 3 mt bn na c kt cu hon chnh.

Edit > Replicate > Radial > Rotate about: ZAxis Number: 3, Angle: 900

SAP2000


Bc 2: Gn gi tr ti trng Bc 3: Gn iu kin bin Bc 4: Thc hin gii

- Chn bc t do cho nt Analyze > Set Options > Click vo 3 [v] UX, [v] UY

v [x] UZ. - Lu bi ton v thc hin gii (F5).

-------------------------------------------------------------------------------------------------------- Bi tp 6 Hy xy dng m hnh h kt cu thp tr, cc s liu v vt liu tng t nh Bi tp 5. Kch thc chn (+0.0m) : 10m10m Tng 1 (+4m) : 8m8m Tng 2 (+8m) : 6m6m Tng 3 (+12m) : 4m4m Tng 4 (+16m) : 2m2m Tng 5, 6, 7 (+18, 20, 22m) : 2m2m

Hc vin t thc hin

SAP2000


3.2. Bi thc hnh s 2 - H khung 3.2.1. Cc quy c c bn

i vi h khung phng trong mt phng OXZ, mi nt s c 03 bc t do l 2 thnh phn chuyn v thng UX, UZ v thnh phn chuyn v xoay quanh trc Y l RY. Vi h khung khng gian, cc nt c y 6 bc t do l UX, UY, UZ v RX, RY, RZ.

Ni lc trong phn t gm 6 thnh phn: lc dc, mmen xon, 2 mmen un v 2 lc ct. Ch rng, kt qu ni lc c xut ra c quy chiu trn h ta a phng ca phn t.

Mi phn t thanh ca h khung c SAP2000 t ng gn mt h trc ta a phng c k hiu bng cc ch s l 1, 2, 3. Khi hin th ch chn mu mc nh, trc 1 c mu (red), trc 2 mu trng (white), trc 3 mu xanh (cyan).

Quy c h trc ta a phng nh sau: (a) Theo phng php hng mc nh (Default Orientation): phng php ny

c chng trnh t ng gn cho phn t khi n mi c to ra. Trc 1 ca phn t lun hng t nt i (nt ch nh trc) n nt j (nt ch nh sau) ca phn t. Cc trc 2 v trc 3 ca phn t c xc nh theo quan h ca trc 1 v trc Z ca h ta tng th theo nguyn tc:

+ Trc 1 v 2 hp thnh mt phng thng ng song song vi trc Z, trc 2 lun hng theo chiu dng ca trc Z.

+ Trc 3 to vi mt phng 1-2 thnh tam din thun (song song vi XY). Trng hp trc 1 ca phn t hng thng ng (khi sin(1-Z)

SAP2000


Assign Frame Local Axes

Ch : vic xc nh h ta a phng ca phn t l rt quan trng trong vic nhp cc d liu cho phn t m bo kt qu chnh xc.

SAP2000 cho php ngi dng nh ngha nhiu loi tit din hoc ly t th vin tit din c sn. Ngoi ra SAP2000 c th nh ngha c loi tit din thay i theo cc quy lut tuyn tnh (linear), bc hai (parabol) hay bc ba (cubic).

Define Frame section Add Nonprismatic

Khai bo ti trng tp trung v phn b u ln phn t (s ti trng tp trung 4): Assign Frame static loads Points and uniform

SAP2000


Khai bo ti trng phn b hnh thang: Assign Frame static loads Trapezoidal

3.2.2. Bi tp thc hnh Bi tp 1: phn tch cc kt cu dm lin tc sau y: Cho bit: q = 10 KN/m, M = 20KNm, m = 0.5KNm/m, P = 15 KN, a = 6m. Dm b tng mc 200, tit din bxh = 25 x 40 cm, Eb = 2,4.103 KN/cm2, = 0,2 . (Khi tnh k n trng lng bn thn ca kt cu).

SAP2000


Trnh t thc hin: Bc 1 : M t hnh hc Chn h n v KN-m, File > New Model From Template > [Beam]

Lu : Click [v] mc Restraints nh hnh minh ha Bc 2 : Khai bo c trng vt liu Define > Materials > [ Add New Materials ]

Material Name : BT200 Mass per unit Volume : 0 Weight per unit Volume : 25 Modulus of Elasticity : 2.4.107 KN/m2 Poissons Ratio : 0.2 Coeff of Thermal Expansion : 0

Bc 3 : Khai bo c trng hnh hc nh ngha c trng hnh hc cho phn t thanh t menu ta chn:

Define > Frame Sections > [Add Rectangular] Section name : D25X40 Material : BT200 Depth [t3] : 0.4 Width [t2] : 0.25

Bc 4 : Gn c trng hnh hc vt liu cho phn t Bc 5 : Khai bo ti trng nh ngha trng hp ti: Define > Static Load Cases. Chn trng hp ti LOAD1 v h s trng lng bn thn bng1 (Self Weight Multiplier: 1).

SAP2000


Lu : khi h s ny bng 1 th trng lng bn thn ca kt cu s c tnh n. - Khai bo ti trng phn b u: chn phn t ngoi cng bn tri (nhp 1).

Assign > Frame Static Loads > Point and Uniform Direction : Global Z Uniform Load : -10

- Khai bo ti tp trung v mmen tp trung trn phn t: chng ta c 2 nhp (nhp 2 v nhp 4).

Gn ti tp trung cho nhp 2: chn nhp 2. Assign > Frame Static Loads >

Point and Uniform

Gn ti tp trung v mmen tp trung cho nhp 4: Lu : mi ln gn chng ta ch c th gn mt loi ti (lc tp trung hoc mmen tp trung).

SAP2000


+ Gn lc tp trung cho nhp 4:chn nhp 4. Assign > Frame Static Loads > Point and Uniform

+ Gn mmen tp trung cho nhp 4:chn nhp 4 Assign > Frame Static Loads > Point and Uniform

- Khai bo ti trng hnh thang cho nhp 3: chn nhp 3 Assign > Frame Static Loads > Trapezoidal

Bc 6 :Thc hin gii - Chn bc t do cho nt Analyze > Set Options > Click vo 2 [v] UZ v [v]

RY. - Lu bi ton v thc hin gii (F5) LU : KHI GII XONG TH TA CH C TH XEM KT QU, KHNG TH HIU CHNH HAY SA CHA. MUN HIU CHNH LI TH : CHN UNLOCK , SAU OK. Bi tap 1 - b: Bai tap 1 - c:

Hoc vien t thc hien

SAP2000


XEM KT QU : 1. XEM CHUYN V NT.

- Chn DISPLAY>Show deformed shape (hoc F6), chn cc thng s tng ng nh : trng hp ti, tu chn options - Click phi mouse ln nt cn xem chuyn v tng ng

2. XEM PHN LC NT - Chn DISPLAY>Show element forces/stresses > Joints - Chn trng hp ti cn xem. - Click chn reaction - Chn OK

3. NI LC PHN T - Chn DISPLAY>Show element forces/stresses > Frames - Chn trng hp ti cn xem. - Chn thnh phn ni lc cn xem - Chn OK Ghi ch : Fill diagram : biu dng t mu Show value on diagram : biu dng gi tr

SAP2000


CC BC KIM TRA V HIU CHNH NU KT QA SAI : 1. Kim tra vt liu khai bo c ng khng

CC BC NH KHAI BO VT LIU, NU SAI TH SA LI. 2. Kim tra xem khai bo tit din c ng khng

LM NH KBO TIT DIN ,NU SAI TH SA LI. 3. Kim tra xem gn tit din cha (quan trng)

- Cch 1 : Click phi chut ln phn t cn kim tra - Xem tronng mc section name c ng tn tit din khng, nu khng phi th lm li theo bc 4 (GN tit din CHO PHN T)

- Cch 2 : chn VIEW>SET ELEMENT - Trong mc FRAME nh du mc SECTION . - Kim tra tng phn t c ng tn tit din khng,nu khng phi th lm li theo bc 4 (GN tit din CHO PHN T)

4. Kim tra cc trng hp ti v t hp ti LM NH KHAI BO TRNG HP TI V T HP TI,

5. Kim tra gn ng ti trng hay cha - Chn Display>Show loads > Joints/Frames. - Chn trng hp ti cn xem(chn thm SHOW LOADINH VALUE, hin th kt qu) - Nu sai th lm li nh hng dn bc 5.

SAU KHI KIM TRA V SA LI CC CH SAI TH NHN F5 CHY LI.

SAP2000


XUT KT QU SANG FILE EXCEL : 1. Chn s mt ct trn 1 phn t cn xut kt qu ni lc .

- Chn cc phn t c cng s mt ct - Chn Assign > Frame > Output Segments

2. nh li s th t phn t trong trng hp phc tp - Chn cc phn t cn nh s th t - Chn Edit > Change Labels

3. Xut kt qu sang file text. - Gii bi ton - Chn File > Print output tables

4. Chuyn kt qu t file text sang file Excel.

SAP2000


Bi tp 2: Phn tch h khung phng Khung b tng ct thp mc 200 Eb = 2,4.103 KN/cm2, = 0,2 . Dm tng 1 : 30 x 60 cm Dm tng 2 n tng 5: 20 x 40 cm Ct tng 1: 50 x 50 cm Ct tng 2 n tng 4: 40x40cm Ct tng 5: 30x30cm (Khi tnh k n trng lng bn thn ca kt cu).

Trnh t thc hin: Bc 1 : M t hnh hc Chn h n v KN-cm, File > New Model From Template > [Portal Frame]

Number of Stories Number of Bays Story Height Bay Width 5 3 5 6

Hiu chnh s hnh hc - Thay i v tr ng li: Draw > Edit Grid (Shift F7)

Chn [x] Glue Joint to Grid Lines Z Location To mi Thao tc

10 9 > [Move Grid Line] 15 13 > [Move Grid Line] 20 25

17 20

>[Move Grid Line] >[Move Grid Line]

X Location

To mi

Thao tc 3 2 > [Move Grid Line] 9 6 > [Move Grid Line]

6m 5m 4m

0.00 m

5.00 m

9.00 m

13.00 m

17.00 m

20.00 m10 KN

10 KN

15 KN

15 KN

20 KN

5 KN/m

10 KN/m

10 KN/m

10 KN/m

20 KN/m

SAP2000


Trc khi hiu chnh Sau khi hiu chnh - Xo bt cc phn t d.

Bc 2 : Khai bo c trng vt liu v tit din hnh hc Bc 3 : Gn c trng hnh hc vt liu cho phn t Bc 4 : Khai bo ti trng Bc 5 : Gn iu kin bin Bc 6 : Thc hin gii

- Chn bc t do cho nt Analyze > Set Options > Click vo 3 [v] UX, [v] UZ v [v] RY. - Lu bai toan va thc hien giai (F5).

Hoc vien t thc hien

SAP2000


Bi tp 3: Phn tch khung b tng ct thp nh cng nghip 1 tng c tit din thay i. B tng mc 200, q = 10KN/m. Ti mt ct 1-1: 3060cm Ti mt ct 2-2: 30100cm Ti mt ct 3-3: 3050cm

Trnh t thc hin: Bc 1 : M t hnh hc Chn h n v KN-m, File > New Model > Cartesian

X Y Z Number of Grid Spaces 2 0 2 Grid Spacing 9 - 7

Hiu chnh v v s hnh hc: - Thay i v tr ng li: Draw > Edit Grid (Shift F7) hoc nhp p ln ng

li bt k. Z Location To mi Thao tc

14 10 > [Move grid line] - Chn phm Draw Framel element v cc phn t thanh . Lu : tt c cc phn t nn v t di ln trn.

Bc 2 : Khai bo c trng vt liu BT200

Bc 3 : Khai bo c trng hnh hc - nh ngha ba tit din ch nht ti u cc phn on.

Define > Frame Sections > [Add Rectangular] Section Name D30x60 D30x100 D30x50 Material BT200 BT200 BT200 Depth [t3] 0.6 1 0.5 Width [t2] 0.3 0.3 0.3

SAP2000


Kt qu sau khi nh ngha

Sau khi khai bo cc tit din u-cui, lc ny trong danh sch tit din s xut hin thm mc mi (Add Nonprismatic) cho php nh ngha loi tit din thay i.

- nh ngha tit din khng lng tr Define > Frame Sections > Add NonPrismatic

Non prismatic Section Name: tn loi tit din Start section, End section: tit din u v cui phn on Length: chiu di mt phn on Length type: kiu chiu di

Vaiable : chiu di tng i Absolute: chiu di tuyt i

EI22, EI33 Variation: quy lut thay i cng cc cnh ca tit din

Linear, parabolic, cubic: tuyn tnh, bc hai, bc ba. Add: nh ngha tit din cho mt phn on Instert: chn mt phn on mi vo trc mt phn on nh ngha Modify: thay i, cp nht cc thng s Delete: hy b mt phn on

Hnh sau m t nh ngha tit din COT, DAM cho phn t ct v dm, s thay i cc m men qun tnh I22 l tuyn tnh, I33 l cubic.

SAP2000


Bc 4 :Gn c trng hnh hc cho tit din (hc vin t thc hin). kim tra xem kt qu gn c trng hnh hc vo

View > Set Element > [v] Show Extrusions

Kt qu nh hnh sau

Bc 5 : Khai bo ti trng. Bc 6 : Gn iu kin bin Bc 7 : Thc hin gii

- Chn bc t do cho nt Analyze > Set Options > Click vo 3 [v] UX, [v] UZ v [v] RY. - Lu bi ton v thc hin gii (F5). -------------------------------------------------------------------------------------------------------- Bi tp 4: Phn tch h khung khng gian. Khung b tng ct thp mc 200 Eb = 2,4.103 KN/cm2, = 0,2 . Dm tng 1 : 30 x 60 cm Dm tng 2 n tng 4: 20 x 40 cm Ct tng trt: 50 x 50 cm Ct tng 1 n tng 2: 40x40cm (Khi tnh k n trng lng bn thn ca kt cu). Ti trng phn b u: Dm tng 1: 20 KN/m Dm tng 2: 15 KN/m Dm tng 3: 10 KN/m.

0.00 m

6.00 m

11.00 m

14.00 m

6m 6m 6m 8m

8m

8m

SAP2000


Trnh t thc hin: Bc 1 : M t hnh hc Chn h n v KN-m, File > New Model From Template > [Space Frame]

Kt qu c nh hnh sau

Hiu chnh s hnh hc - Thay i v tr ng li: Draw > Edit Grid

(Shift F7) Chn [x] Glue Joint to Grid Lines Z Location To mi Thao tc

12 11 > [Move Grid Line] 18 14 > [Move Grid Line]

X Location To mi Thao tc 12 14 > [Move Grid Line]

Chn mt phng 3D View l hin hnh, hiu chnh li gc nhn nh sau: View > Set 3D View

SAP2000


Kt qu c nh hnh sau

- Xo bt cc phn t d: c th xo trc tip cc phn t d trn mt phng 3-D View hoc s dng nt a mt phng X-Y Plane v cc cao Z v mt phng Y-Z Plane v cc to khc nhau theo ng li, sau xo cc phn t d.

Kt qu c nh hnh sau

Bc 2 : Khai bo c trng vt liu v c trng hnh hc Bc 3 : Gn c trng hnh hc cho phn t

- Dng cng c ng thng Set Intersection Line Select Mode ct qua cc i tng chn nhanh cc phn t ct.

- Dng ca s Window hoc mt phng X-Y Plane chn nhanh cc phn t dm.

SAP2000


Bc 4 : Khai bo ti trng. Bc 5 : Gn iu kin bin Bc 6 : Thc hin gii

- Chn bc t do cho nt Analyze > Set Options > Click vo 6 [v] UX, [v] UY[v] UZ v [v] RX, [v] RY, [v] RZ hoc chn nhanh . - Lu bi ton v thc hin gii (F5). -------------------------------------------------------------------------------------------------------- Bi tp 5: Phn tch h khung khng gian kt cu thp nc.

Khung b tng mc 300 Eb = 2,9.103 KN/cm2, = 0,18. Ct chng tit din 25x60cm. Cc dm dai vng v ai cho kch thc tit din l 20x40cm. Ti trng phn b u ln ai vng v ai cho nh ct : Theo phng ng : 20KN/m Theo phng ngang : 3 KN/m.

Hng dn: to ra cc h ta tr cc cao trnh 4m, 8m v 12m v dm ai. S dng pht sinh Edit Replicate Radial Ch : + Bn knh ai vng cao trnh 4m l 1.0833m + Bn knh ai vng cao trnh 8m l 0.9167m + Bn knh ai vng cao trnh 12m l 0.75m Phn tch s b:

- H c l loi kt cu phc tp, c 3 ct khng ng phng hoc song song, ngoi ra mt s dm dai v dm c dng hnh trn. Ti trng ni chung khng phc tp.

- v cc ct chng ch cn thc hin cho mt ct v xoay thnh 3 ct.

- Cc dm trn c v trong h to tr, vi gc chn cung mt phn t dm l 15o.

4m4m

4m

3m

1.5m

Mat bang nh cot (+12.00m)

R=1.25m

Mat bang chan cot (+0.00m)

SAP2000


Trnh t thc hin Bc 1: Xy dng s hnh hc h kt cu

- Chn h n v Ton-m. - To h thng li File > New Model > Cartesian

X Y Z Number of Grid Spaces 6 0 3 Grid Spacing 0.5 - 4

- Chn mt phng quan st X-Z Plane. - Hiu chnh to cc ng li: nhp p ln ng li thng ng bt k

X Location To mi Thao tc 0.5 0.75 > [Move Grid Line] 1.0 1.25 > [Move Grid Line]

-0.5; -1.0 > [Delete Grid Line] - V thanh chng xin v thanh dm cho . - Chia phn t ct thnh 3 on v phn t dm

ngang thnh 4 on. Minh ho chia phn t ct thng 3 on: chn phn t ct T menu Edit > Divide Frames

Bc 2: nh ngha c trng vt liu v c trng hnh hc

- nh ngha c trng vt liu BT300 v hnh hc C25x60, D20x40. - Gn c trng hnh hc cho cc phn t ct v dm.

Bc 3: Hon thin s hnh hc kt cu Chn tt c phn t Edit > Replicate > [Radial] Rotate about: Z Axist Angle: 120; number: 2

SAP2000


To cc dm ai - Thm vo h to tr mi

Option > Set Coordinate System > [Add System] > [Cylindrical] System Name: CSYS1

Grid spaces Grid spacing Along Radius 1 1.0833 Along Theta 24 15 Along Z 0 1

[Advanced]> [Translation] Z : 4

+ Chn h to CSYS1 lm h to hin hnh v thit lp mt trong hai ca s mn hnh ch mt phng rt (Z=0)

SAP2000


- Chn cng c v nhanh phn t thanh dm [Quick Draw Frame Element], nhp vo mt cung bt k.

- Nhn bn phn t va v c c ton b vnh ai cao trnh 4.0m. T menu: Edit > Replicate > [Radial]

Rotate about: Z Axist Angle: 15; number: 23

- Gn c trng hnh hc D20X40 cho dm ai va to

- Vi cch lm tng t ta c th v c vnh ai ng knh 0.9167m cao trnh 8.0m v hai vnh ai ng knh 1.5m, 3.0m cao trnh 12m. Sau v xong nn gn c trng hnh hc cho phn t lin sau .

Bc 4: Kim tra mt phng qun tnh ca tit din cho cc phn t. - i vi phn t dm th rt n gin do h trc ta mc nh cho phn t nm ngang ph hp vi mt phng qun tnh ca tit din khai bo, cho nn khng cn phi thay i. - i vi hai ct chng nm ngoi mt phng X, Z nu chng trnh khng t ng xoay h tr to a phng th ta phi quay mt gc ph hp, c th nh sau: + Ct c to y dng quay mt gc +60o + Ct c to y m quay mt gc -600. - Trong trng hp c th ny, do hai ct nm ngoi mt phng XZ c to ta t ct nm trong mt

Trc khi pht sinh phn t Sau khi pht sinh phn t

SAP2000


Hnh chiu phi cnh ton kt cu

phng XZ, m h to mc nh ca n ph hp. Do vy khi pht sinh, chng trnh thc hin lun vic quay h trc to cho phn t mi. Kt qu l ta khng cn thay i h to a phng ca bt k phn t no.

Bc 5: Gn ti trng tc dng

- Chn tt c cc phn t dm ti mt phng cao trnh 12 m. - Gn ti phn b u theo phng ng :20 KN/m; theo phng ngang : 3 KN/m.

Bc 6: Gn iu kin bin Bc 7 : Thc hin gii

- Chn bc t do cho nt Analyze > Set Options > Click vo 6 [v] UX, [v] UY[v] UZ v [v] RX, [v] RY, [v] RZ hoc chn nhanh . - Lu bi ton v thc hin gii (F5).

2

3 Hng mc nh

3 (Hng khai bo)

2 (Hng khai bo)

Gc quay =-60o

SAP2000


3.3. Bi thc hnh s 3 - Kt cu tm v 3.3.1. Cc quy c c bn

Trong SAP2000 s dng phn t v tng qut m t cho cc kt cu c dng tm chu un (plate) hay tm chu lc mng (membrane). Phn t v ca SAP2000 c hai loi phn t mu l cc t gic 4 nt hoc tam gic 3 nt. Phn t v c xem nh phng tuyt i v c m hnh ha bi mt phng trung bnh ca n.

Ch : khi khai bo phn t v cho kt cu, m bo kt qu tnh ton c tt, ta cn phi m bo cc yu cu sau y:

+ Cc gc bn trong ca phn t v phi nh hn 1800, gc tt nht l 900. i vi phn t tam gic khong t 450 n 1350.

+ T s gia cc cnh ca phn t v khng nn qu ln. SAP2000 s dng loi phn t c hm xp x chuyn v khng tng thch (non-

conforming displacement function). Khi tnh ton, chng trnh s t ng thm vo cc hm xp x gc xoay cho cc nt ny. Sau khi tnh ma trn cng, cc thnh phn tng ng vi bc t do ca cc nt thm vo s b kh i. iu ny cho php nng cao chnh xc ca phn t v kh c hin tng shear-locking trong phn t.

Phn t v tng qut c y 6 bc t do. Tuy nhin, i vi tng loi phn t v c s dng, ta cn khng ch cc bc t do khng cn thit, c th:

+ i vi phn t v chu un (plate): ta cn khng ch 2 thnh phn chuyn v thng v mt thnh phn chuyn v xoay trong mt phng phn t.

+ i vi phn t v chu lc mng (membrane): ta cn khng ch cc chuyn v vung gc vi mt phng v chuyn v xoay ngoi mt phng phn t. 3.3.2. Khai bo cc loi ti trng

Ti trng bn thn: Ta c th khai bo h s ti trng bn thn ca kt cu l 1 chng trnh t ng

tnh ton. Ch rng, vic khai bo ny s p dng cho tt c cc phn t trong kt cu. i vi phn t tm, ti trng bn thn s phn b u ln mt phng phn t theo hng (-Z), gi tr bng trng lng ring nhn vi b dy tm.

Trng hp ngi dng ch mun khai bo ti trng bn thn cho mt s phn t no trong kt cu, ta phi dng chc nng khai bo nh sau:

SAP2000


Assign Shell static loads Gravity

Ti trng phn b u (uniform load): Loi ti trng ny phn b u ln mt trung bnh ca phn t, c th ch nh theo

cc phng khc nhau: Assign Shell static loads Uniform

Ti trng p lc b mt (Surface pressure load) Ti trng b mt c th khai bo tc dng ln bt k mt no (trong 6 mt) ca phn

t v, hng ca lc lun vung gc vi mt phng m n tc dng. Ch rng, trong phin bn 7.42, chng ta ch c th khai bo trc tip bng ha ti b mt tc dng ln mt 5 v 6 ca phn t. Mun khai bo cc b mt khc, phi hiu chnh trc tip vo tp tin d liu ca SAP2000.

Assign Shell static loads Pressure

SAP2000


Ngoi ra ta c th khai bo mt mt phng ti trng tc dng ln phn t v bng cch s dng Joint Pattern. Vic ny rt tin li khi khai bo mt phng p lc nh ca p lc nc ln thnh b, p lc t ln tng chn

Joint Pattern l tp hp cc nt m mi nt s c gn cc gi tr Pi, gi tr ca cc nt ny c xc nh bng hm sau:

Dz.Cy.Bx.AP iiii +++= (biu din mt phng ti trng).

Trong A, B, C, D l cc h s c ch nh trc. xi, yi, zi l ta im nt. Khai bo Joint Pattern Define Joint Pattern

Chn cc nt to thnh mt Pattern v thc hin: Assign Joint Pattern

V d: p lc nc cao 3m l hm tuyn tnh theo phng Z nn ta khai bo: Dz.CP i += , A = B = 0, C = -10, D = 30 (KN/m2).

3.3.3. Kt qu ni lc Quy c v du ca cc thnh phn ni lc v ng sut nh hnh sau:

SAP2000


3.3.4. Cc bi tp thc hnh Bi tp 1: phn tch kt cu tm trn chu un vi bin ngm theo chu vi tm. Tm c ng knh D = 4m Ti trng phn b u q = 20KN/m2. Ti trng tp trung chnh gia tm P = 30KN Vt liu bng b tng mc 250 c: Modun n hi E = 2.65.103 KN/cm2. H s Poisson =0.2

Trnh t thc hin: - M t hnh hc ca tm bng vic s dng h to tr. - Khai bo cc c trng vt liu v chiu dy tm. - Khai bo ti trng tc dng ln tm. - M t iu kin bin trng hp ngm. - Thc hin gii.

Bc 1 : M t hnh hc ca tm bng vic s dng h to tr - Chn h n v KN-m - To li: t menu File > New model > Cylindrical

- Chn phm Quick Draw Rectangular Shell Element v nhanh phn t tam gic nh hnh v, sau chia phn t nh hn.

-

Chn phn t mi v, t menu Edit > Mesh Shell

SAP2000


Ch : Trong qu trnh chia nh li nu phn t c chia nh khng theo mun th ta dng chc nng UNDO hu b thao tc sau lm li.

- Nhn bn s phn t c c li cho mt tm trn: chn tt c phn t, t menu Edit > Replicate > Radial

Kt qu ta c li phn t cho ton b tm bn

Bc 2 : Khai bo c trng hnh hc v vt liu Define > Materials > [ Add New Materials ]

Weight per unit Volume : 25 KN Modulus of Elasticity : 2.56.107 KN/m2 Poissons : 0.2

Define > Shell Sections > [ Add New Section] Section name : TAM Material : BT250 Thickness > Membrance : 0.1

Thickness > Bending : 0.1 Type : [x] Plate

SAP2000


Gn c trng vt liu v hnh hc cho tt c cc phn t ca tm. - Chn tt c cc phn t - Assign > Shell > Sections > TAM

Bc 3 : Khai bo ti trng Gn ti trng phn b u: chn tt c cc phn t

Assign > Shell Static Loads > Uniform Load : -20 KN/m2 Direction: Global Z

Gn ti trng tp trung : chn nt ti tm Assign > Joint Static Loads > Forces Gi tr ti trng : -30 KN

Hng ca lc tc dng: Global Z

Ch : trong bi ton ny c tnh n trng lng bn thn ca tm. Bc 4 : Khai bo iu kin bin

- Chn tt c cc nt trn bin, Assign > Joint > Restraint - Dng Fast Restraints : chn ngm

Ch : gn iu kin bin c nhanh, nn thc hin bc ny trong qu trnh m t hnh hc (bc 1) trc khi nhn bn s phn t. Bc 5 : Thc hin gii

- Chn bc t do cho nt Analyze > Set Options > [ XY plane] - Lu bi ton v thc hin gii (F5)

SAP2000


Bi tp 2: Phn tch kt cu b nc c kch thc 3x3x2m. Mc nc cao 1.8m t y b. Thnh b dy 0.1m, y b dy 0.15m. Vt liu b tng mc 250 c cc s liu nh bi tp 1. B nc xem nh lin kt ngm ti chn thnh b. Hng dn: nh ngha p lc nc, dng cch gn ti trng p lc ln phn t shell thng qua Joint Pattern.

Phn tch s b: Bn mt ca kt cu i xng trc vi nhau, do vy ta ch cn v mt mt v pht sinh thnh 3 mt cn li. Mt y cn li d dng v c. Trnh t thc hin: Bc 1 : M t hnh hc Chn h n v KN-m, to h li t menu File > New Model > Cartesian Chn mt phng XZ (y=-1.5m), dng Quick Draw Rectangular Shell Element v hai phn t tm.

Khai bo c trng vt liu v hnh hc - Khai bo vt liu : tng t bi tp 3-1 - Khai bo c trng hnh hc (c hai loi)

Define > Shell Sections > [ Add New Section ] Loi Section 1 Loi Section 2 Section Name THANH DAY Material BT250 BT250 Thickness > Membrance Thickness > Bending

0.1 0.1

0.15 0.15

SAP2000


Type () Shell , [ ] Thick Plate

() Shell , [ ] Thick Plate

Gn loi c trng hnh hc THANH cho hai phn t mi v Pht sinh to 4 thnh b, chn tt c cc phn t

Edit > Replicate > [Radial] Rotate about: Z Axist

Angle: 90; number: 3 Chn tt c cc phn t thnh b, chia mi phn t thnh 5x5 phn t con (Edit > Mesh Shell) v gn cho nhm THANH (Assign > Group Name > [Group: THANH > Add new group name ] )

V mt y - Chn mt phng quan st XY (Z=0). - Dng cng c v nhanh v 4 phn t y. - Gn c trng hnh hc DAY cho 4 phn t ny. - Chn cc phn t y chia mi phn t thnh 5x5 phn t con. - Gn tt c cc nt v phn t bn y cho nhm DAY.

Kt qu hnh dng ca b nh sau:

SAP2000


Bc 2 : Khai bo ti trng Nhn thy rng mc nc trong b cao 1.8 m khng trng vi v tr nt ti cao trnh . Do vy ta s chia dy phn t trn cng quanh thnh b thnh 2 lp c chiu dy 0.2m. Cch lm nh sau:

- Chn gc nhn cho ca s khng gian View > Set 3D View Plane : 270 ; Elevation : 0 ; Aperture : 0

- Dng cng c ng thng ct qua cc i tng chn cc phn t. - Chia nh li Edit > Mesh shell > Mesh into 1 by 2

nh ngha nhm Pattern: Define > Joint pattern Pattern : APLUC > [ Add new pattern ] Khai bo Pattern

- Chn nhm THANH: Select > Select > Groups > THANH - Trong ca s mt phng XY (Z=2) Select > Deselect > Pointer/Window.

Chn tt c cc nt trong mt phng ny loi chng ra khi danh sch cc i tng c chn.

Gn gi tr cho Pattern APLUC: Assgin > Joint Pattern

C th kim tra li gi tr ca Pattern khai bo Display > Show Pattern > [APLUC]

SAP2000


Gn gi tr ti trng cho thnh v y - Chn nhm DAY, gn ti phn b Assign > Shell Static Loads > Uniform

- Chn nhm THANH, Assign > Shell Static Loads > Pressure

thy rng, tt c cc phn t u c trc php tuyn hng ra ngoi b, do vy ti p lc thu tnh s c chiu cng vi chiu trc 3 (mang du dng). Bc 3 : p t iu kin bin ngm cho bn gc Bc 4: Thc hin gii

- Chn bc t do cho nt Analyze > Set Options > [Space Frame]. - Lu bi ton v thc hin gii (F5).

SAP2000


Bi tp 3: Phn tch kt cu thp nc hnh tr trn xoay dng cc phn t shell. Vt liu b tng mc 250 c cc s liu nh bi tp 1. Xem nh chn ct ngm ti mt t. B chu p lc nc thy tnh cao trnh l +14.7m v p lc gi ln mt thnh l 1,2KN/m2 . Kch thc hnh hc ca thp nc nh sau: Chn thp hnh ng D = 1m, dy 0.15m, cao 12m. y b trn D = 1m, dy 0.3m ( ct +12.0m) y nn ct dy 0.2m (t ct +12.0m n ct 12.6m) Thnh b hnh tr D = 3m, dy 0.15m, cao 2.1m (t ct +12.6m n ct +14.7m) Np nn ct dy 0.1m, cao 0.3m (t ct +14.7m n +15.0m) C np b hnh tr D = 0.5m, dy 0.1m, cao 0.2m (t ct +15.0m n +15.2m)

Phn tch s b: Kt cu thp trn xoay i xng trc v c 5 phn on. Trong c 3 on l hnh tr v hai on l nn ct. m t hnh hc ca kt cu, cc on hnh tr s c ly t th vin ca chng trnh, hai on cn li s c v rp ni vi cc on ban u. thun tin, theo hng chu vi ca ton kt cu s c chia thnh 24 gc, sau khi to c hnh hc th cng on gn c trng hnh hc cng c thc hin tip theo. Trnh t thc hin: Bc 1 : M hnh ho kt cu Chn h n v KN-m V chn thp File > New Model From Template > [Cylinder]

Khai bo cc thng s c trng hnh hc v vt liu cho ton kt cu, i vi vt liu ta c mt loi BT250 v hnh hc c nm loi gm COT, DAYBE, DAYNON, THANH V NAP.

- Khai bo vt liu: tng t bi tp 3-1

0.15

0.3 0.2

0.1

0.1

12m

0.6m

2.1m

0.3m

0.2m

0.15

D = 1.0m

D = 3.0m

D = 0.5m

SAP2000


- Khai bo c trng hnh hc: (c nm loi) Define > Shell Sections > [ Add New Section ]

Loi 1 Loi 2 Loi 3 Loi 4 Loi 5 Section name COT DAYBE DAYNON THANH NAP Material BT250 BT250 BT250 BT250 BT250 Thickness > Membrance Thickness > Bending

0.15 0.15

0.3 0.3

0.2 0.2

0.15 0.15

0.1 0.1

Type () Shell [ ]Thick Plate

() Shell [ ]Thick Plate



() Shell [ ] Thick Plate

Chn tt c phn t v gn cho nhm COT ng thi gn c trng hnh hc cho chng. V hnh tr thn thp: Edit > Add To New Model From Template > [Cylinder]

Number of Circumferential Spaces 24 Number of height space 7 Cylinder height 2.1 Radius 1.5 Restraint [ ], Gridline [x] Advance > Translation Z 12.6

Chn tt c phn t ca phn tr va to gn cho nhm THANH v gn c trng hnh hc cho nhm. Sau khi to thm phn tr thnh b, chng trnh s t ng thm vo mt h to tr mi l CSYS1 v thit lp cho n h to hin hnh. d quan st, trn mn hnh nn hai ca s, mt quan st ch khng gian v mt quan st mt phng. V phn y b (phn y nm trn nh ct):

- Chn h to hin hnh Option > Set Coordinate System > GLOBAL - Trong mt phng rt (Z=12m), v phn t tam gic v chia n ra thnh 2 phn

theo hng bn knh. - Pht sinh 2 phn t va chia c y b : Edit > Replicate > [Radial]

Rotation about : Z axist Angle : 15 ; Number : 23

- Chn tt c cc phn t trong mt phng gn cho nhm DAYBE v c trng hnh hc cho nhm.

V phn y nn ct: - Trong ca s khng gian, thit lp cc gii hn quan st v gc nhn sao cho

ch thy c hai ng bin: mt ng bin di ca phn thnh bn trn v mt ng bin ca y b trn nh ct.

SAP2000


- View > Set Limit Set X Axis Limits Set Y Axis Limits Set Z Axis Limits Min 0 0 12 Max 1.5 1.5 12.6

- View > Set 3D View Plan Elevation Aperture 270 90 0

Kt qu nh sau:

- V phn t v i qua 4 nt nh hnh trn - Chia phn t ny thnh 4 phn theo hng bn knh. Pht sinh 4 phn t va

chia c ton b phn y nn, sau chn ton b cc phn t y nn v gn cho nhm DAYNON (lm tng t nh phn DAYBE).

- Phn kt cu thp va c to nh sau

SAP2000


Phan ket cau va c tao

V phn np nn ct v c np: tng t phn trc mun v c phn np nn ct th phn c np hnh tr nn c v trc ri sau thay i gc nhn v gii hn khng gian quan st v phn np. Trong qu trnh v th ng thi gn lun c trng hnh hc cho b phn kt cu. Ch : Sau khi m hnh ho xong kt cu chn li h to hin hnh l GLOBAL. Bc 2 : M t ti trng tc dng ln kt cu

- nh ngha Pattern: Define > Joint Pattern Pattern : APLUC > [ Add New Pattern ]

- Khai bo Pattern Chn nhm THANH v DAYNON. Gn gi tr cho Joint Pattern : Assgin > Joint Pattern Pattern Name : APLUC; C = -10; D = 147

i vi mt y xin, p lc nc tc dng theo phng thng ng, do vy khi dng ti trng Pattern khai bo ta phi chiu ln phng vung gc b mt y nn, h s cos = 0.86, thnh phn ti trng nm trong mt phng y c b qua.

SAP2000


Gn gi tr ti trng: - p lc thng ng do khi lng nc tc dng ln y b, chn nhm

DAYBE. Assign > Shell Static Loads > Uniform

Load : -27 KN/m2 Direction : global Z

- Gn ti trng cho y nn, chn nhm DAYNON Assign > Shell Static Loads > Pressure By Joint Pattern : APLUC Multiplier : -0.86 Lu : ti trng p lc thu tnh cng chiu vi trc 3 phn t, do nn hin th chiu trc 3 phn t trc khi khai bo p lc thu tnh m bo gn chnh xc h s Multiplier. - Gn ti trng cho thnh b, chn nhm THANH Assign > Shell Static Loads > Pressure By Joint Pattern : APLUC Multiplier : 1 - Gn ti trng gi: gii hn khng gian quan st View > Set Limit

Set X Axis Limits Set Y Axis Limits Set Z Axis Limits Min -1.5 0 0 Max 0 1.5 15.2

n gin p lc gi c coi l phn b u v ch tc dng vo mt na b mt ca kt cu. Chn tt c cc phn t trong mt phng gii hn khng gian quan st ` Select > Deselect > Groups > [ DAYBE ]

Assign > Shell Static Loads > Uniform Load : 1.2 KN/m2 Direction : global X

Bc 3 : p t iu kin bin ngm ti chn ct, khai bo bc t do v thc hin gii.

Chon goc nhn quan sat

SAP2000


3.4. Bi thc hnh s 4 - Kt cu c lin kt n hi 3.4.1. Cc quy c c bn

SAP2000 cung cp cc lin kt n hi c m hnh ha bng cc l xo t ti cc im nt. Lin kt n hi c s dng rng ri trong cc kt cu dm lin tc trn nn n hi (mng bng), tm trn nn n hi (mng b), tnh ton cc Vic xc nh cc h s n hi l rt quan trng, nh hng n kt qu tnh ton.

Trong SAP2000, khai bo c cc nt c lin kt n hi ta chn cc nt cn khai bo v thc hin:

Assign Joint Springs

Ch : n v ca cng l xo l [lc/n v di] hoc [lc/gc xoay n v]. Ngoi ra ta c th nhp trc tip cc s hng ca ma trn cng ca lin kt bng

cch chn mc Advanced trong ca s trn (cch ny rt t dng):

Khi gii quyt cc bi ton thuc lnh vc nn n hi, vic xc nh h s nn thng dng theo m hnh nn Winkler (m hnh nn 1 thng s) v tnh n gin v ph hp vi mt s loi t thng dng. Tuy nhin m bo kt qu tnh chnh xc, ngi s dng cn tham kho thm cc m hnh nn khc.

cng chuyn v thng theo phng trc 1

cng chuyn v xoay theo phng trc 2

SAP2000


Gio trnh ny gii thiu cch tnh cng ca lo xo theo h s nn c xc nh theo cng thc Hansen. Bng h s nn ca mt s loi t thng dng:

Stt Loi t H s nn (KN/m3) 1 t ct xp 4800-16000 2 t ct cht va 9600-80000 3 t ct cht 6400-12800 4 t st pha ct cht va 32000-80000 5 t bn pha ct cht va 24000-48000

Cng thc xc nh cng ca l xo dm trn nn n hi, cc, tng c: sslx l.b.kk =

Trong : klx : cng l xo theo phng vung gc vi dm. ks : h s nn ls : khong cch gia cc l xo.

i vi trng hp tm trn nn n hi, cng l xo c xc nh: effsi A.kk =

Trong Aeff l din tch cc phn t trong vng nh hng ca n. 3.4.2. Cc bi tp thc hnh Bi tp 1: Phn tch bi ton dm (mng bng) c tit din 30x80cm, bng b tng mc 250 t trn nn n hi nh hnh v, h s nn 60000 kN/m3, a=6m.

Hng dn: chia dm thnh 48 on c chiu di 0.5m. Cc l xo bin c cng = 60000 x 0.3 x 0.25 = 4500 kN/m Cc l xo trong nhp c cng = 60000 x 0.3 x 0.5 = 9000 kN/m. Trnh t thc hin: Bc 1 : M t hnh hc Chn h n v KN-m, File > New Model From Template > [Beam]

SAP2000


Lu : Click [ ] mc Restraints nh hnh minh ha Bc 2 : Khai bo c trng vt liu v c trng hnh hc

- Khai bo c trng vt liu Define > Materials > [ Add New Materials ]

Material Name : BT200 Mass per unitt Volume : 0 Weight per unit Volume : 25 Modulus of Elasticity : 2.4.107 KN/m2 Poissons Ratio : 0.2 Coeff of Thermal Expansion : 0

- Khai bo c trng hnh hc Define > Frame Sections > [Add Rectangular]

Section Name Material Depth [t3] Width [t2] D30x80 BT250 0.8 0.3

Bc 3 : Gn c trng hnh hc v khai bo ti trng tp trung cho phn t. Bc 4 : Chia nh dm thnh mi on c chiu di 0.5m. Chn [all], t menu Edit > Divide Frames Divide into: 12

Last/First ratio: 1

Bc 5 : Gn cng l xo cho cc nt

- Chn tt c cc nt bn trong dm.

Cc nt bn trong dm

SAP2000


Assign > Joint > Spring [Spring Stiffness in Local Direction] > Translation 3 : 9000

- Chn hai nt bin (hai nt u dm). Assign > Joint > Spring

[Spring Stiffness in Local Direction] > Translation 3 : 4500 Bc 5 : Thc hin gii

- Chn bc t do cho nt Analyze > Set Options > Click vo 2 [v] UZ v [v] RY. - Lu bi ton v thc hin gii (F5). -------------------------------------------------------------------------------------------------------- Bi tp 2: Phn tch kt cu tm trn nn n hi (mng b), chu cc ti trng tp trung ti cc chn ct l 300 kN. Kch thc tm 10m10m, dy 0.5m, vt liu b tng mc. H s nn 70000 kN/m3. Hng dn: chia tm thnh 100 phn t c cnh 1m. cng l xo gc = 70000 0.25 = 17500 kN/m cng l xo bin = 70000 0.5 = 35000 kN/m cng l xo gia = 70000 1 = 70000 kN/m.

SAP2000


Trnh t thc hin: Bc 1 : M t hnh hc Chn h n v KN-m, File > New Model > Cartesian

X Y Z Number of Grid Spaces 1 1 0 Grid Spacing 10 10 -

Chn phm Quick Draw Rectangular Shell Element v nhanh phn t tm

Bc 2 : Khai bo c trng vt liu v c trng hnh hc. Bc 3 : Gn c trng hnh hc cho phn t , sau chia tm thnh 100 phn t c cnh 1m. Chn phn t tm T menu, Edit > Mesh Shells

SAP2000


Bc 4 : Gn ti trng tp trung cho phn t Bc 5 : Gn cng l xo cho cc nt

- Chn tt c cc nt bn trong tm.

Assign > Joint > Spring [Spring Stiffness in Local Direction] > Translation 3 : 70000

- Chn tt c cc nt bin Assign > Joint > Spring

[Spring Stiffness in Local Direction] > Translation 3 : 35000 - Chn 4 nt gc tm

Assign > Joint > Spring [Spring Stiffness in Local Direction] > Translation 3 : 17500 Bc 5 : Thc hin gii

- Chn bc t do cho nt Analyze > Set Options > Click vo 3 [v] UX, [v] UZ v [v] RY. - Lu bi ton v thc hin gii (F5).

Cc nt bn trong tm

Cc nt bin

SAP2000


3.5. Bi thc hnh s 5 - T hp ti trng 3.5.1. Khi nim v t hp ti trng

Theo TCVN 2737-95 (tiu chun ti trng & tc ng), ti trng tc dng trn cng trnh gm c cc ti trng thng xuyn v ti trng tm thi. Do tnh cht ca ti trng tm thi tc dng khng ng nht v v tr v thi gian, do vy xy ra nhiu trng hp ti (load case) khc nhau dn n kt qu ni lc trong kt cu cng khc nhau.

tm c ni lc nguy him nht ti mt v tr no trong kt cu, phng php chnh xc l v ng nh hng ca ni lc ti v tr , sau tm v tr bt li nht ca ti trng theo phng php ca C hc kt cu. SAP2000 hon ton c th thc hin c vic ny, tuy nhin khi lng tnh ton i vi cc h siu tnh s rt ln v tn nhiu thi gian (vic v ng nh hng bng SAP2000 s c cp trong mc 3.7 khi phn tch kt cu chu ti trng di ng).

Ngoi ra, SAP2000 cho php chng ta to ra nhiu trng hp ti khc nhau v t hp cc trng hp ti tm ni lc nguy him nht. Cch lm ny ch l gn ng, tuy nhin ngi s dng cn c nhiu kinh nghim nh ngha cc trng hp ti sao cho t nht m vn tm c ni lc nguy him nht. Nu tham kho cc tiu chun ca nc ngoi, chng ta c th thy s trng hp ti rt t so vi TCVN2.

T hp ti trng (load combination) l s kt hp cc trng hp ti trng c th xy ra ng thi. Nu kt cu c phn tch trong min n hi, chng ta c th dng nguyn l cng tc dng, th t hp ti trng cng chnh l t hp ni lc.

SAP2000 h tr 04 phng php t hp ti trng khc nhau: Phng php cng tc dng (ADD): kt qu ni lc ca cc trng hp ti c

nhn vo h s t hp v c cng i s vi nhau. Kiu t hp ny c dng cho cc trng hp ti trng tnh.

Phng php biu bao (ENVELOP): kt qu ni lc ti mt mt ct ca phn t c ly theo gi tr ln nht (Max) v nh nht (Min) ca mt trong s tt c cc trng hp ti trng nhn vi h s t hp tng ng. Kiu t hp ny p dng cho ti trng tnh v ti trng di ng. Lu rng, phng php ny ch p dng cho cc phn t thanh (frame element).

Phng php tr tuyt i (ABS): gi tr tuyt i ca cc kt qu phn tch tng trng hp ti c cng li vi nhau, cc gi tr dng (+) v m (-) c t ng tnh.

Phng php bnh phng cc tiu (SRSS): gi tr t hp l cn bc hai ca tng bnh phng cc trng hp ti. Loi t hp ny s cho hai gi tr dng v m i vi mi phn on phn t hoc ti cc nt.

Lu : Trong bi ton kt cu, thng thng ta ch cn s dng 02 phng php cng tc dng ADD v phng php biu bao ENVE t hp ti trng v v biu bao ni lc cho kt cu. 3.5.2. Khai bo cc trng hp ti

SAP2000 lun nh ngha sn mt trng hp ti trng c tn l LOAD1, lun tnh n trng lng bn thn ca kt cu.

2 Hin nay ang c nhiu nghin cu v vn t hp ti trng cho nh nhiu tng. Kt qu so snh cho thy, trong

nhiu trng hp, cch t hp ti trng theo TCVN qu rm r m vn khng cho kt qu ln hn cc t hp ca cc tiu chun nc ngoi nh ACI (M), BS (Anh), BAEL (Php)

SAP2000


nh ngha mi mt trng hp ti, ta thc hin: Define Define static loadcase\Add New Combo

Ta c th khai bo nhiu trng hp ti khc nhau. Ch , vic khai bo gi tr cho Type ch l tng trng v khng nh hng n kt qu tnh ton. Type c th l DEAD (ti trng tnh), LIVE (hot ti), WIND (ti gi), SNOW (ti trng tuyt), QUAKE (ti trng ng t) v OTHER (cc ti trng khc). 3.5.3. T hp ti trng

Sau khi nh ngha cc trng hp ti, ta tin hnh t hp ti trng: Define Load combination

Lu : khi t hp ti trng cho nh nhiu tng, ta nn to ra 1 trng hp ti ch tnh ti trng bn thn ca kt cu v cc ti trng thng xuyn khc (lun xut hin trong cc trng hp ti). Cc trng hp hot ti c to ra khng tnh ton ti trng bn thn na (khai bo selfweight factor = 0). Khi tin hnh t hp nhiu trng hp ti, cn lu khng c trng lp cc hot ti (tham kho thm cc gio trnh v t hp ti trng). T hp cui cng s l bao ca tt c cc t hp trc v biu bao ni lc.

Tn t hp ti trng

Cch t hp

Tiu t hp

H s ca trng hp ti

Cc trng hp ti c trong t hp

SAP2000


3.5.4. Bi tp thc hnh Bi tp 1: v biu bao ni lc cho dm lin tc 4 nhp sau y: Dm c tit din 20x40cm, b tng mc 200, mdun n hi E = 2,4.103 kN/cm2, h s Poisson v = 0.3 Cc trng hp ti nh sau: Cho G = 10 kN, P = 12 kN, khi tnh k n trng lng bn thn ca kt cu.

Thc hin t hp cc trng hp ti trng vi cu trc t hp sau y: T hp 1 = 1 + 2 T hp 2 = 1 + 3 T hp 3 = 1 + 4 T hp 4 = 1 + 5 T hp 5 = 1 + 6 T hp 6 = ENVE (T hp 1, 2, 3, 4,5) (biu bao).

SAP2000



Lu : Click [v] mc Restraints nh hnh minh ha Bc 2 : Khai bo c trng vt liu

Define > Materials > [ Add New Materials ] Material Name : BT200 Mass per unit Volume : 0 Weight per unit Volume : 25 Modulus of Elasticity : 2.4.107 KN/m2 Poissons Ratio : 0.3 Coeff of Thermal Expansion : 0

Bc 3 : Khai bo c trng hnh hc nh ngha c trng hnh hc cho phn t thanh t menu ta chn:

Define > Frame Sections > [Add Rectangular] Section name : D20X40 Material : BT200 Depth [t3] : 0.4 Width [t2] : 0.2

Bc 4 : Gn c trng hnh hc vt liu cho phn t Bc 5 : Khai bo ti trng Khai bo cc trng hp ti

SAP2000, lun lun nh ngha sn mt trng hp ti trng LOAD1, trong trng hp ti ny lun tnh n trng lng bn thn ca kt cu. Mc nh trng lng bn thn ca kt cu c xc nh theo chiu Z.

Cc trng hp ti nn c hoch nh sn v khai

SAP2000


bo trc t hp ti trng. nh ngha cc trng hp ti, t menu: Define > Define Static Loadcases - Load: Tn trng hp ti trng, tn c th bao gm cc k t ch v s nhng

khng di qu 8 k t. - Type: Loi ti trng, tu chn ny ch l hnh thc phn no ni ln tnh cht ca

trng hp ti, nu chng c ch nh hay khng u khng nh hng n kt qu tnh ton, nhng trong chng trnh c h tr tnh nng thit kt cu kin. Cc tnh ton thit k ph thuc vo cc tiu chun (code), trong ngi ta quy nh phi xt n cc t hp ti trng no. Nu loi ti trng c ch nh th chng trnh s t ng xc nh c cc t hp ti trng theo chun phc v cho bc tnh ton thit k hay kim tra tit din.SAP2000 nh ngha sn cc loi ti trng sau:

DEAD: Trng hp ti trng tnh LIVE: Trng hp hot ti WIND: Trng hp ti trng gi SNOW: Trng hp ti trng tuyt QUAKE: Trng hp ti trng ng t

OTHER: dng ch nh mt trng hp ti no khng thuc cc loi trn chng hn nh ti trng bt n nh.

- Seft Weight Multiplier: H s nhn vi ti trng lng bn thn, nu h s ny khc khng th trng hp ti s bao gm c ti trng do trng lng bn thn ca kt cu.

Add New Load: To mt trng hp ti trng mi Change Load: Thay i cc thng s ca trng hp ti c chn Delete Load: Loi b trng hp ti c ch nh Kt qu sau khi khai bo 6 trng hp ti.

SAP2000


T hp cc trng hp ti Bc t hp ti trng, bt buc phi thc hin sau khi nh ngha cc trng hp

ti, nhng n cng c th khai bo trc khi cc d liu ti trng cho tng trng hp c khai bo. T menu Define > Load Combination > [Add New Combo]

Load combination name: Tn ca t hp ti trng Load combination Type: Phng php t hp ti trng Title: Dng m t t hp ti Define Combination.

Case Name: Trng hp ti Scale Factor: H s nhn cho trng hp ti. Add: thm trng hp ti vo t hp hin hnh. Modify: Cp nht thay i cc thng s. Delete: Loi b trng hp ti ra khi t hp hin hnh. [x] Use for Steel/Concrete Design: Dng t hp ti ang nh ngha tnh ton thit k thp/ b tng Minh ho khai bo Combo1 (T hp 1) v Combo6 (t hp 6). Cc Combo khc lm tng t - Khai bo Combo1:

Define > Load Combination > [Add New Combo]

SAP2000


- Khai bo Combo 6: (xem hnh trn) Define > Load Combination > [Add New Combo]

Kt qu sau khi khai bo 6 trng hp t hp ti

Bc 6 : Gn ti trng cho tng trng hp ti Minh ho gn ti trng cho TH1.

Gn ti trng TH1: chn cc phn t cn gn ti trng. Trng hp ny chn [all] T menu Assign > Frame Static Loads > Point and Uniform

Kt qu nh hnh sau

Chn trng hp ti cn gn

SAP2000


Cc trng hp ti cn li , thc hin tng t Bc 7 :Thc hin gii

- Chn bc t do cho nt Analyze > Set Options > Click vo 2 [x] UZ v [x] RY. - Lu bi ton v thc hin gii (F5) Bi tp 2: V biu bao ni lc ca h khung phng ca bi tp 2 mc 3.2.2. Cc trng hp ti do ngi c t nh ngha. (hc vin t thc hin) Bi tp 3: V biu bao ni lc cho h khung khng gian ca bi tp 3 mc 3.2.2. Cc trng hp ti do ngi dng t nh ngha. (hc vin t thc hin) 3.6. Bi thc hnh s 6 - Kt cu phc hp 3.6.1. H khung dn

H khung dn thng gp trong cc kt cu nh cng nghip, trong h khung l b tng ct thp v h dn mi bng thp. SAP2000 hon ton c th m hnh ha c s h khung dn lm vic ng thi ch bng cc phn t thanh. Ngi dng ch cn khai bo mt s thng s v c trng hnh hc th c th phn bit c hai loi phn t ny. Khi thc hin m t kt cu phc hp khung dn cn ch cc iu kin sau y:

+ i vi cc nt thuc h dn s bc t do l 02 (i vi h phng) hay 03 (i vi h khng gian) chnh l cc chuyn v thng. i vi cc nt thuc h khung ta khai bo bc t do cho mi nt l 3 (i vi h phng) hay 6 (i vi h khng gian). i vi cc nt lin kt gia khung v dn, do cc nt c s bc t do khng ging nhau nn phi dng iu kin rng buc cc chuyn v nt (constraint) ni chng li. Vic ny chnh l m bo iu kin lin tc v mt chuyn v ca kt cu.

+ Lu quan trng: Nu khai bo h s ti trng bn thn l 1 trong cc trng hp ti, SAP2000 s p dng cho tt c cc phn t, trong c thanh dn. Do vy trong thanh dn s xut hin mmen un, lc ct loi b iu ny cn thit phi khai bo h s ti trng bn thn bng 0. Mun tnh ti trng bn thn cho phn t no ta s s dng chc nng gn ti trng gravity load cho phn t .

Nu ngi s dng khng nm vng vic khai bo rng buc cc bc t do ca nt th c th s dng chc nng gii phng ni lc. Chn phn t cn gii phng ni lc v thc hin: Assign Frame Realease

Vic gii phng ni lc cn ch im u (start) v im cui (end) ca phn t m bo kt qu chnh xc. 3.6.2. H khung - tm v

H khung - tm v rt thng gp trong thc t nh h khung - sn b tng ct thp ca nh nhiu tng, cc b nc c gia c dm, kt cu cu Vic gii quyt kt cu khung sn

SAP2000


lm vic ng thi theo h khng gian mi thc s phn nh gn ng nht s lm vic ca kt cu tht, c tnh n nh hng ng k ca tm sn vo trong h khung3.

V mt m hnh kt cu khung sn, SAP2000 ch c th m hnh ha bng cc mt phng cho h sn (shell element) v ng thng cho h khung (frame element), do khng nhn thy c s tng quan v mt kch thc tht ca chng. m bo kt qu tnh ton chnh xc, cn chia nh sn ng thi chia nh dm kt ni vi nhau ti cc nt. Ch rng, phng php phn t hu hn yu cu cc phn t phi c kt ni vi nhau thng qua cc nt4. 3.6.3. H khung vch cng

i vi kt cu nh nhiu tng, ngi ta thng thit k kt cu theo h khung vch cng (hay li cng) chu ti trng ngang (gi). Cc vch cng c SAP2000 m t bng phn t v tng qut (shell element)5. Nh vy, vic m t cc li cng ca kt cu nh nhiu tng lun thc hin c ch bng cc phn t shell. Tuy nhin, do li cng c b tr nhiu v tr trn mt bng nn cn phn tch kt cu khung vch theo s khng gian m bo kt qu chnh xc.

M hnh sn tuyt i cng Khi phn tch s khung sn hay khung vch

cng, mi nt ca cc phn t ny u c 6 bc t do nn lun tha mn tnh lin tc ca chuyn v. Tuy cc m hnh ny c chnh xc cao nhng s bc t do tng th ca kt cu s tng ln ng k, nn thi gian gii quyt bi ton cng tng ln.

Qua nghin cu tnh ton, ngi ta thy rng, di tc dng ca ti trng ngang, cng ca h sn trong mt phng ca n l rt ln, bin dng rt b so vi bin dng ngoi mt phng sn. Do vy ngi ta a ra m hnh sn tuyt i cng tnh ton. Theo m hnh ny, tt c cc nt trong mt phng sn u c

chuyn v v gc xoay (trong mt phng sn) bng nhau v sn l mt Rigid body. SAP2000 h tr khai bo m hnh ny bng cch rng buc cho mt nhm nt c chuyn v bng nhau nh m hnh Diaphragm Constraint. Nu kt cu c nhiu sn hay cc mt phng c cng rt ln th chng ta s khai bo nhiu Diaphragm Constraint. Theo m hnh ny s n s ca bi ton gim xung ng k v thi gian gii quyt nhanh hn nhng vn m bo kt qu chnh xc.

khai bo mt Diaphragm trong SAP2000,

3 Mt kt qu ng ghi nhn l khi phn tch kt cu khung sn lm vic ng thi, mmen un v lc ct trong

cc dm v ct gim t 15% n 30% so vi phn tch h khung thng thng. 4 Li chia nh sn m khng chia nh tng ng phn t dm sn rt thng gp i vi ngi s dng khng

hiu v phng php phn t hu hn. 5 Trong SAP2000 khng c phn t dnh ring tnh ton vch cng. Ch c cc phn mm tnh kt cu chuyn

dng mi c loi phn t ny, chng hn nh ETABS

SAP2000


chng ta chn tt c cc nt thuc mt phng cng v thc hin: Assign Joint Constraint\Add Diaphragm

Tn Diaphragm

Xc nh h ta a phng ca Diaphragm

Xa b mt rng buc Diaphragm

Mi Diaphragm u c mt h ta a phng xc nh mt phng cng. Trc th 3 ca h ta ny lun vung gc vi mt phng cng. Ngi dng ch cn ch nh trc th 3 cho mi Diaphragm.

SAP2000


Ni chung, khi phn tch kt cu phc hp c nhiu loi phn t khc nhau m s bc t do ca cc nt (tng ng vi phn t ) khc nhau, m bo iu kin lin tc ca chuyn v, ta cn thit phi khai bo cc rng buc gia cc chuyn v .

SAP2000 h tr khai bo rt nhiu kiu rng buc chuyn v ca cc nt ty theo yu cu ca ngi s dng (Assign Joint Constraint), c th:

+ Rng buc chuyn v nt Restraints: khai bo cc chuyn v ca nt. + Rng buc Diaphragm: tt c cc chuyn v trong mt phng Diaphragm l bng

nhau (m hnh sn tuyt i cng). + Rng buc Body Constraint: m t mt khi hay mt phn ca kt cu l mt

khi cng (Rigid Body). Tt c cc thnh phn chuyn v tng ng ca cc nt trong khi u bng nhau. Kiu rng buc ny thng dng trong khung - ging

+ Rng buc Plate Constraint: Tt c cc nt thuc kiu rng buc ny s to ra cng mt chuyn v chng li bin dng un ngoi mt phng Plate. Kiu rng buc ny ngc vi Diaphram, thng dng khi cn ni cc nt c bc t do khc nhau, chng hn nh phn t dm - phn t khi (frame - sodid).

Ngoi cn c th nh ngha nhiu kiu rng buc khc nh Rod, Beam, Equal, Local, Weld. Ngi s dng c th xem chi tit trong ti liu SAP2000-Analysis References (version 10.0.1 - CSI). 3.6.4. Bi tp thc hnh Bi tp 1: V biu M v Q ca h dm ghp sau y. Tit din dm 20x35cm, b tng mc 200. Khi tnh b qua trng lng bn thn ca kt cu.


SAP2000


Ngm Gi di ng

dong

Gi di ng

dong

Kt qu c nh sau

Ni thanh 1 & 2 hon tt s hnh hc. Chn thanh 1 & 2: T menu Edit > Join Frames

Bc 2 : Khai bo c trng vt liu v c trng hnh hc Bc 3 : Gn c trng hnh hc vt liu cho phn t Bc 4 : Khai bo ti trng Bc 5 : Gn iu kin bin

Bc 6 : Gn khp cho cc nt - Tch nt: chn tt c cc nt cn gn khp

T menu, Edit > Disconnect . Sau khi thc hin thao tc ny, mi nt c chn trc b tch thnh 2 nt, c th Click chut phi vo nt kim tra. Khi Click chut phi vo nt cn gn khp ngoi cng bn tri, kt qu c nh hnh bn.

- Gn khp cho nt:

Chn nt cn gn khp (lc ny l 2 nt) bng ca s nh hnh trn. T menu: Assign > Joint > Constraints > [Add Equal]

SAP2000


- Lm tng t cho 2 khp cn li. Bc 6 : Thc hin gii

- Chn bc t do cho nt Analyze > Set Options > Click vo 2 [v] UZ v [v] RY. - Lu bi ton v thc hin gii (F5). -------------------------------------------------------------------------------------------------------- Bi tp 2: Phn tch kt cu h khung dn. Thanh dn l thp gc u cnh L70x70x5 (F=6.86cm2). H khung bng b tng ct thp, mc 200, tit din ct l 30x30cm, dm 20x40cm. Khi tnh ton b qua ti trng bn thn ca h dn, nhng vn tnh n ti trng bn thn ca h khung. Trnh t thc hin: Bc 1 : M t hnh hc Chn h n v KN-m, File > New Model > Cartesian

X Y Z Number of Grid Spaces 2 0 3 Grid Spacing 9 - 5

Hiu chnh v v s hnh hc: - Thay i v tr ng li: Draw > Edit Grid (Shift F7) hoc nhp p ln ng

li bt k. Chn [x] Glue Joint to Grid Lines Z Location To mi Thao tc

10 9 > [Move Grid Line] 15 12 > [Move Grid Line]

15kN/

3m x 3 = 9m 3m x 3 = 9m

+ 5. 0m

+ 0. 0m

+ 9.0m

+12.0m 20kN 20kN

30kN 20kN

20kN

10kN 8kN

SAP2000


- Chuyn v mt phng XZ. - Chn phm Draw Frame Element v cc phn t thanh .

Kt qu sau khi v nh sau:

- Chia nh 2 thanh dn v 2 thanh dm trn cng thnh 3 phn bng nhau. T menu: Edit > Divide Frames

Divide into: 3 Last/First ratio: 1

- V tip cc thanh cn thiu hon thin s hnh hc.

Bc 2 : Khai bo c trng vt liu v c trng hnh hc - c trng vt liu: gm 2 loi thp (THEP) v b tng mc 200 (BT200)

Thep Be tong

SAP2000


- c trng hnh hc: Thanh dn: xem li 3.1 (h dn) Dm v ct : hc vin t thc hin.

Bc 3 : Gn c trng hnh hc vt liu cho phn t. Bc 4 : Khai bo ti trng

Lu : khi khai bo c trng vt liu ca THEP, ta gn trng lng bng 0, do ti trng bn thn ca h dn s khng c tnh n. chng trnh t ng tnh ti trng bn thn ca h khung, ta khai bo h s nhn ti trng bn thn (Selfweight multiplier) bng 1 hoc s dng chc nng tnh ti trng do trng lc (gravity load) cho cc phn t h khung (trong trng hp khai bo h s nhn ti trng bn thn bng 0). Bc 5 : M hnh ho s h kt cu dn v khung lm vic ng thi.

- Chn 3 nt ti v tr lin kt gia dn v khung nh hnh sau:

T menu, Edit > Disconnect - Chn nt bn tri bng ca s (lm tng t bi 1, t menu

Assign > Joint > Constraints > [Add Equal]

- Lm tng t cho 2 nt cn li. Bc 6 : Gn iu kin bin Bc 7 : Thc hin gii

- Chn bc t do cho nt Analyze > Set Options > Click vo 3 [v] UX, [v] UZ v [v] RY. - Lu bi ton v thc hin gii (F5).

SAP2000


Bi tp 3: Phn tch kt cu phc hp h khung-sn theo s khng gian vi 2 trng hp sau y v so snh kt qu: Trng hp 1: Xem sn l tuyt i cng trong mt phng ca n (rng buc Diaphragm). Trng hp 2: Xt n s bin dng ca sn trong mt phng ca n (sn mm). Cc s liu: LxB = 4x4m, chiu cao tng H = 4m Ct : 30x30cm, Dm : 20x40cm, Sn: dy 80cm Vt liu l b tng mc 200. Ti trng phn b u trn sn l 3kN/m2. Ti trng gi quy i v ct (theo mt phng) l 3,2kN/m cho mt n gi v 2,4kN/m cho mt khut gi.

Trnh t thc hin: Trng hp 1: Bc 1 : M t hnh hc Chn h n v KN-m, File > New Model From Template > [Space Frame]

V hai phn t tm cho sn tng 1 v sn tng 2. Bc 2 : Khai bo c trng vt liu v c trng hnh hc Bc 3 : Gn c trng hnh hc vt liu cho phn t Bc 4 : Khai bo ti trng Bc 5 : Hon thin s kt cu.

- Chn tt c phn t sn (shell), t menu : Edit > Mesh Shells

Mesh into : 5 By : 5

- Chn cc phn t dm , t menu: Edit > Divide Frames

SAP2000


Divide into: 5 Last/First ratio: 1

Bc 6 : Khai bo m hnh sn tuyt i cng

- Chn tt c cc nt sn tng 1, t menu: Joint > Assign > Constraints > [Add Diaphragm]

- Lm tng t cho sn tng hai. Bc 7 : Thc hin gii

- Chn bc t do cho nt : khung khng gian. - Lu bi ton v thc hin gii (F5). Trng hp 2: Lm tng t trng hp 1 nhng khng phi thc hin Bc 6.

giao_trinh_sap2000-fem.pdf

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