Chuong 3- tin hoc xay dung

Phn II- Phn mm SAP2000

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Chng 3 Thit lp s v tnh Kt cu h thanh

1. Khi nim v phn t thanh

1.1. Phn t thanh ( Frame )

- Phn t (PT) thanh dng cho cc cu kin nh dm, ct,dn, khung, dy cp . . . ca cc kt cu phng hoc khng gian.

- Phn t thanh ni chung l mt on thng biu din qua trc ca cu kin, c hai nt, k hiu i v j, l phn t hai (2D) hoc ba chiu (3D) (dm, ct) chu un theo hai trc, chu xon, bin dng dc trc v bin dng ct theo hai trc, m t cho cc kt

cu dm, dn, khung 2D hoc 3D.

- Cc loi kt cu dng phn t thanh bao gm :

+ Dm - Beam

+ Khung khng gian 3D Frame

+ Dn khng gian 3D Truss

+ Khung phng 2D Frame

+ Dn phng 2D Truss

+ H dm li phng Plane Grid

+ Dy cp Cable .

- Mt phn t thanh m hnh ho nh mt ng thng ni gia hai im. Mi phn t c h to ring khai bo cc c trng tit din (mt ct ngang), ti trng v th hin kt qu ni lc a ra.

- Mi phn t thanh c th chu cc loi ti trng (TT) thng thng nh TT bn thn, ti trng tp trung v ti trng phn b v mt s TT c bit khc nh TT nhit, ng sut trc, TT ng. Khi tnh cho PT thanh cng c th k n nh hng ca vng cng

(End offsets) ti giao im gia dm v ct hoc gii phng cc thnh phn ni lc

(release) ti cc u ca phn t.

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ng dng Tin hc trong Thit k cng trnh

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- Ni lc phn t thanh a ra ti hai u thanh hoc ti cc mt ct cch u nhau, dc theo chiu di phn t. Mi phn t thanh c hai nt k hiu l I v J (khng c trng nhau ti mt im). Mi nt thng thng c ti a su bc t do (ba bc chuyn

v thng v ba bc chuyn v xoay). Tuy nhin, ba bc t do xoay s khng hot ng

ti mt nt nu phn t khng c cng m men v ti trng mmen ti nt. iu ny xut hin trong nhng tnh hung sau :

+ Vng cng ti u no l 0 v cc c trng mt ct ngang hnh hc J, I33, I22 u bng 0 ( vi A, AS2 v AS3 khc 0 ) hoc

+ Vng cng ti u no bng 0 ; cc thnh phn m men xoay R2 v R3 c gii phng u hoc thnh phn xon R1 gii phng ti u kia.

+ Khi cc iu kin ny xy ra c hai u, phn t thanh lm vic nh mt phn t dn.

- Thanh coi l thng ng nu gc nghing vi Z


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- Hng mc nh :

+ Trc 1 (mu ) c hng theo hng trc thanh i t nt u n nt cui ( i j theo trnh t khai bo nt) .

+ Trc 2 (mu trng) v trc 3 (xanh c ban) xc nh bi mi quan h theo qui tc bn tay phi v quan h gia trc 1 v trc Z. Trc 2 thng ly theo phng thng

ng ( ging +Z ),tr phi phn t c hng trng vi Z th trc 2 chn theo hng

ca +X.

+ Trc 3 lun nm ngang ( trong mt phng X-Y )

+ Mt phng 1-2 ly sao cho lun song song vi trc Z, c hng thng ng.

- Cc phn t c coi l c hng thng ng nu gc nghing gia trc 1 v trc Z nh hn 10 3 . Gc gia trc 2 v trc thng ng cng bng gc gia trc 1 v mt

phng nm ngang. iu ny c ngha l vi cc phn t nm ngang trc 2 hng theo

phng thng ng .

- i vi h thanh trc giao hng mc nh nh sau :

+ trc +1 // +X ; +2//+Z +3// -Y

+ trc +1 // +Y ; +2//+Z +3// +X

+ trc +1 // +Z ; +2//+X +3// +Y

- thanh c h ta ring nh mc nh, khi v cc phn t nn theo trt t t tri sang phi, t di ln trn. Hnh sau biu din mi quan h gia h Global v HTR theo mc nh (Hnh 3.1) :

Hnh 3.1



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- Gc to phn t :

Cch ny dng khai bo hung ca phn t khc vi cc hng mc nh. Vi cc phn t thng ng, gc to l gc gia trc 2 v trc nm ngang +X. Ngc li, gc

ta l gc gia trc 2 v mt phng thng ng cha trc 1.

C th hiu nm na l, gc khai bo s l gc tnh t trc 2 hoc trc 3 (nu xt theo mc nh) quay ti trc 2 hoc trc 3 m bn nh khai bo (khc vi mc nh) .

Hnh 3.2 V d v s tng quan gia cc trc theo mc nh v trc khai bo mi

- Khi khai bo gc to phn t c th :

+ i chiu ca trc 1

+ Cho php quay trc 2&3 mt gc quanh trc 1. Gc l dng khi quay ngc chiu kim ng h nu nhn t chiu dng trc 1 .Gc mc nh s c gi tr dng nu

chiu quay theo qui tc vn nt chai (ca trc 1) l ngc chiu kim ng h ( cho trc 1 hng v pha bn m gc quay l ngc chiu kim ng h gc c gi tr dng).

- Cc loi ti trng tc dng ln PT thanh :

+ TT tp trung trn phn t

+ TT phn b ( u hoc khng u )

+ Trng lc, TT bn thn

+ TT nhit

+ TT US trc, bin dng

+ TT ng ( Response Spectrum & Time History )

+ TT di ng



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- Ni lc ca phn t thanh: c 6 thnh phn :

P - Axial force : Lc dc V1,V2 Shear force : Lc ct

M22, M33 Moment: Mmen un T- Torsion : Mment xon

Hnh 3.3 Mt s dng biu ni lc ca PT thanh

1.2. Phn t thanh phi tuyn, lin kt ta ( Nllink- link support )

Phn t Nllink hay cc phn t lin kt ta dng cho m hnh kt cu phi tuyn cc b nh

cc khe(Gap), b gim sc (damper) ca t, ch cch in (isolator) v nhng ni c cc

lin kt c bit( Hook, Multilinear Plasstic, Multilinear Elasstic, Friction Isolator . . .). S lm vic phi tuyn biu th ch khi phn tch vi hm thi gian phi tuyn. i vi cc phn

tch khc, cc phn t ny lm vic tuyn tnh.

Mi phn t Nllink,Link/ Support c th biu th bng mt gi n hi ni vi t qua mt hoc nhiu im hoc qua mt lin kt ni vi nhau qua 2 im. Cc c trng cho mi

loi phn t u khai bo nh nhau.

Mi phn t gi thit l 6 thnh phn gi n hi khc nhau, biu th cho 6 bc t do bin dng (bin dng dc trc, ct, xon v un thun ty). Mi gi n hi ny c 1 cp (dual)

cc c trng ring. Trong :

- cng tuyn tnh v cc c trng tt dn dng cho cc phn tch tuyn tnh.



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- Mi quan h lc - bin dng phi tuyn ty chn dng cho phn tch hm thi gian phi tuyn.

Hnh 3.4 Hp thoi khai bo Property cho phn t Nllink/Link Support

Nu cc c trng phi tuyn ty chn khng khai bo cho mt bc t do no , cc c

trng cng tuyn tnh c dng cho cc phn tch hm thi gian phi tuyn.

c trng tt dn ch dng cho phn tch ph phn ng v phn tch hm thi gian tuyn

tnh.

Mi lin h lc - bin dng phi tuyn ca cc gi n hi ny c th l 1 cp (coupled) hoc khng phi cp, ph thuc vo kiu lm vic ca m hnh.

Mt tp ca cc c trng cho 6 bc t do gi l Property. Mi Property bao gm : khi

lng, trng lng, v 6 mi quan h gia lc - bin dng tuyn tnh v phi tuyn, c th dng cho mt hoc nhiu phn t Nllink, Link/Support.

Cc kiu lm vic phi tuyn m hnh ho bng loi phn t ny bao gm :

+ Cn nht

+ Cc khe (cho trng hp nn) v cc mc (hook) cho trng hp ko.

+ Do 1 trc

+ Do 2 trc da trn ch cch (m)

+ Ma st - con lc da trn nhng ch cch.



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Mi phn t c h to ring khai bo cc c trng lc - bin dng v thng bo kt qu a ra.

Mi phn t Nllink/Link Support c th chu trng lc (theo hng bt k). Kt qu a ra

bao gm bin dng mt ct ngang phn t v ni lc ti cc nt ca phn t.

Ch : phn t Nllink/Link Support c coi l c di bng 0 khi :

- Phn t c 1 nt n.

- Phn t 2 nt vi khong cch t nt i n nt j nh hn hoc bng s gia di bng 0 m ngi dng khai bo (thng thng gi tr mc nh l 10-3).

- Phn t Nllink/Link Support lun c 6 bc t do ti mt hoc 2 im nt ca phn t.

Trong hu ht cc loi kt cu, vic khai bo h to ring l rt n gin. Cc phng php trnh by trn cho bn nhng kh nng m t hng ca phn t Nllink/Link

Support. Phng php n gin nht l dng hng mc nh v gc to phn t

Nllink/Link Support.

Cc bin dng trong (internal Deformations - ni bin dng) : c 6 bin dng trong c lp

khai bo cho phn t Nllink/Link Support. Cc bin dng ny tnh t cc chuyn v tng

i ca nt j so vi nt i i vi phn t 2 nt v chuyn v ca chnh n i vi phn t 1 nt.

Mi Nlprop (Property) khai bo mi lin h lc - bin dng phi tuyn ty chn. Cc c

trng phi tuyn ny c dng v ch dng khi phn tch hm thi gian (Time history) phi tuyn.

Trong khi khai bo Property, SAP cho php khai bo cc c trng hiu ng cng

(effective stiffness), hiu ng cn (effective - damping). Cc c trng ny dng cho mi phn tch tuyn tnh, bao gm : phn tch tnh, phn tch P.Delta, phn tch dng dao ng

(modal), phn tch Ti trng di ng, Ph phn ng, phn tch Dao ng iu ho hoc

phn tch Hm thi gian tuyn tnh hoc c chu k.

C 6 mi quan h lc - bin dng m ch yu (nh hng) quyt nh n s lm vic ca

phn t.

Mi quan h bin dng v lc n hi:

- Lc dc trc : fu1vs.du1

- Lc ct : fu2vs.du2, fu3vs.du3

- Lc xon : fr1vs.dr1

- Un thun ty : fr2vs.dr2, fr3vs.dr3



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Trong fu1, fu2 v fu3 l cc lc ni n hi (internal - spring forces) v fr1, fr2 v fr3

l cc mmen ni n hi.

Cc ni lc phn t : cng nh phn t thanh, ni lc phn t Nllink/Link Support bao gm

P, V2, V3 l cc lc dc, lc ct trong mt phng 1-2, mt phng 1-3 v T, M2, M3 l cc

lc xon, mmen trong mt phng 1-3, mt phng 1-2. Cc gi tr ny c m t qua cc lc v mmen n hi.

2. To lp m hnh kt cu

2.1. Thit lp s hnh hc

2.1.1. T th vin mu

Trong SAP2000 c mt h thng th vin mu phong ph to sn mt s loi kt cu.

vo th vin mu :

File New Modal trn mn hnh s hin hp thoi nh trn hnh 3.5, c cc , mi s a ngi s dng thit lp mt dng kt cu dm, dn, khung, v, tng cng, cu

thang, cu dy vng... to ra cc kt cu ny, ngi s dng chn loi s v sau

cung cp cc gi tr cho mt s tham s c th m s i hi (hnh 3.6). Tu theo cc nhm d liu, c th to nn cc dng kt cu khc nhau.

Hnh 3.5 Hnh 3.6

Sau y s gii thiu cch thit lp mt s loi kt cu .

- Beam : Thit lp h dm trc giao. Cc thng s gm :

+ Number of span : S nhp



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+ Span length : chiu di mt nhp

+ Section property : chn loi tit din cho dm

- 2D Trusses

Thit lp cc loi dn phng, trong phn ny

ngi s dng c quyn chn mt

trong cc dn c hnhch nht, tam gic,

a gic, sau a vo cc tham s nh :

+ Number of division N1,N2: S khoang

+ Division length : Chiu di mt khoang

+ Height H1,H2 : chiu cao dn

+ Span Length L1,L2 : Chiu di nhp.

Hnh 3.7 Cc tham s khai bo mt dn phng

- 3D Truss :

Thit lp cc loi dn

khng gian : cc loi dn mi v thp

tr. Trong th vin ca SAP2000 c 5

loi dn khc nhau:

+ Roof Truss: Dn mi

+ Transmission Tower 1 :

Dn hnh thp c 2 phn, phn

di loe (hnh thang),phn trn thng

Hnh 3.8 Cc tham s khai bo cho dn khng gian

+ Transmission Tower 2 :Dn thp thang, mt bng ch nht

+ Transmission Tower 3: ( hnh 3.7) Dn thp hnh lng tr, mt bng hnh ch nht.

+ Transmission Tower 4 : Dn thp 3 chn, hnh lng tr, mt bng hnh tam gic.

Trong phn ny, khi khai bo cc thng s dn, ngi s dng s a vo cc s liu cho

tng mc (theo cao ca dn ), mi mc trn mt dng gm c :

+ Elevation i : cao mc th i



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+ Width i : rng mc i

+ a,b : cc gi tr xc nh v tr cc thanh cho trong dn.

hiu thm v cc thng s, cc k hiu nhn vo Parametric Definition, chng trnh

hin hnh v vi cc k hiu nh trong phn di ca hnh 3.7.

- 2D Frame

Thit lp cc khung phng c hoc khng c thanh ging cho.

C cc loi khung :

+ Khung phng trc giao ( Portal)

+ Khung phng c ging cho giao nhau (Braced Concentric)

+ Khung phng c ging cho lch tm (Braced Eccentric)

Khi gi th vin mu, cc ging cho s xut hin cc khoang nhp chn. khai bo cho cc loi khung, thng phi nhp cc thng s sau :

+ Number of Stories : S tng

+ Number of Bays : S nhp

+ Story height : Chiu cao mi tng

+ Bay width : rng mi nhp

+ Gap width : rng khe h gia 2 thanh ging

+ Section Properties : chn cc loi tit din ( c) gn lun cho cc phn t dm, ct, thanh ging trong qu trnh gi th vin mu .

Hnh 3.9 Khai bo cho khung phng c ging cho khng giao nhau

- 3D Frame :



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Thit lp cc khung khng gian c hoc khng c cc tm sn. Th vin mu khung khng gian ca SAP2000 c 4 loi :

+ Open Frame Building : khung c dm ct gia, khng c sn.

+ Perimater Frame Building : khung khng c dm,ct gia, khng c sn

+ Beam-Slab Building : khung c dm ct gia, c bn sn.

+ Flat Plate Building : khung khng c cc dm gia, c cc tm sn.

Khi gi th vin mu cho cc khung trn, cn a vo cc thng s:

+ Number of Stories : S tng

+ Number of Bays, X & Y : S nhp theo cc phng X & Y

+ Story height : Chiu cao mi tng

+ Bay widths X,Y : rng mi nhp theo phng X,Y

+ Section Properties : chn cc loi tit din ( c) gn cho cc phn t dm, ct, thanh ging ca khung.

Hnh 3.10 Kt cu Open Frame Building Hnh 3.11 Kt cu Flat Plate Building

2.1.2. Gii thiu v h li : File / New Modal/ Grid only

Li l h ph tr, h tr trong qu trnh to lp s hnh hc. Li c th hai hoc 3

chiu, c to cho gn ging vi s kt cu cn thit lp .

C hai loi h li :

- Theo to cc ( Cartersian ): thit lp h li khng gian trc giao, cn khai bo :



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+ S ng li hay s cc khong li (Number of Grid Lines hoc Number of Grid Spaces)

+ ln mi khong ( Grid Spacing) theo 3 trc X,Y,Z .

- Theo h to tr ( Cylindrical ) : khai bo

+ s ng trn ng tm (along radius)

+ s gc chia (s mi) (along theta)

+ s khong chia theo phng Z ( along z) v gi tr ca 3 tham s trn .

Hp thoi thit lp h li cho 2 loi trn th hin trong cc hnh sau:

Hnh 3.12 Hnh 3.13

Vi phin bn V7.4: chnh sa li dng Draw Edit Grid .

Vi cc phin bn sau ca SAP( t SAP2000V_8), trong hp thoi Coordinate

System/Grid, nhn Edit Grid, SAP2000 s hin ln bng cc thng tin v cc dng li

theo 3 phng, cho php ngi dng sa nh mt tp vn bn thng thng (hnh 3.15). Trong phn ny, ngi dng c th chnh sa theo ta tng dng li (chn Ordinate ),

hoc theo cc khong cch li (chn Space). Ngi dng cng c th thay i n v

trong qu trnh chnh sa. Cc d liu chnh trong bng s c chng trnh cp nht ngay trong ha.

- Cc bc thao tc khi to li :

+ To ra mt h li u ban u : File New Modal Grid Only Chn loi li Khai bo cc tham s ( s cho h li ban u u nhau trn mi phng)

+ Chnh sa cc bc li cho ph hp vi m hnh sp to:



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- thm dng li :

+ G gi tr vo X (Y,Z) location

+ Nhn Add Grid Line

- Thay i to li :

+ Chn mt dng li

+ Thay i gi tr trong Location

+ Nhn Move Grid Line

- Xo cc dng li

+ Chn cc dng li trong Location

+ Nhn Delete All

Hnh 3.14

Hnh 3.15 Hp thoi chnh sa h li qua bng

2.2. Khai bo vt liu

khai bo cc c trng vt liu (c l) vo menu Define Material

C mt s loi vt liu m SAP2000 t tn v cho sn cc gi tr c trng c l l

Concrete (b tng), Steel(thp), Alum(nhm). Tuy nhin, ngi dng vn c th s dng cc tn ny v thay i cc gi tr trong phn ny ph hp vi mnh (vo Frame/Cable Frame Property Modifier). Trong phn Other (bt k) cho php ngi dng t tn mi v



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t thay th gi tr vt liu mnh mun khai bo vo cc ( mc nh chng trnh hin cc

gi tr ca Steel).

( Xem chng II Giao din ha ca SAP2000 phn Define >Material bit thm

thng tin cho phn ny).

Trong nhng phin bn gn y ca SAP2000, phn khai bo c trng vt liu (hnh 3.15) ngi dng c th khai bo chi tit hn cc thng tin lin quan n thit k cu kin

(Design Property Data), cc gi tr lin quan khi tnh cho hm thi gian (Time Dependent

Property), n tnh cht cn ca vt liu (Material Damping Property), v khai bo cho cc ng cong ng sut bin dng ca vt liu(Stress Strain Curve Definition). . .

Hnh 3.16 Hp thoi khai bo cc c trng vt liu

Cc c trng c bn cho mt loi vt liu bao gm :

- M un n hi E (cho cng dc trc v cng un) .

- M un ct g (cho cng xon v cng ct theo phng ngang) c tnh t E v h s poisson u.

- Khi lng ring ( trn n v th tch ) m : khi lng phn t tnh ton .

- Trng lng ring (trn n v th tch ) w : cho trng lng bn thn tnh ton .

- Ch s thit k : khai bo cc thng s lin quan n phn thit k.

Ty theo s kt cu v yu cu tnh ton m ngi dng c th nhp chnh xc mt s

hoc tt c cc thng s trong phn ny.V d, trong mi trng hp hoc nu ch tnh ni lc ch cn khai bo E, nu k n TT bn thn khi tnh ton th phi khai bo chnh xc

c E,W, . . .



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2.3. Khai bo cc loi tit din

2.3.1. Cc c trng mt ct ngang

Cc c trng mt ct ngang khai bo c lp vi khai bo phn t, n c th i din cho mt nhm phn t v c gn cho cc phn t. Cc c trng mt ct ngang khai

bo theo h to ring ca phn t, trong trc 1 dc theo trc phn t v vung gc

vi mt ct v qua giao im ca hai trc tm ca mt ct. Hng 2 v 3 thng song song hai trc tm phn t, thng trc 2 ly theo kch thc chnh (chiu cao mt ct) v

trc 3 theo chiu rng (chiu nh hn), tuy nhin khng bt buc nh vy.

Hnh 3.17 Khai bo tit din ch nht Hnh 3.18 Khai bo cho tit din vnh khuyn

Cc c trng mt ct bao gm :

2.3.1.1. Cc c trng cho vt liu (xem phn 2.2)

2.3.1.2. Cc c trng cho dng hnh hc ca tit din ( mt ct ngang )

+ Din tch mt ct ngang a

+ M men qun tnh i33 v i22 (un trong mt phng 1-2 v 1-3), cng un tng ng ca mt ct l i33* e1 v i22* e1.

+ Hng xon J : cng xon ca mt ct tnh theo J*g12.

+ Din tch ct as2 v as3 : ct theo phng ngang trong mt phng 1-2 v 1-3.

+ Nu cc gi tr a, j, i33 hoc i22 bng 0 s cho cc cng ca mt ct bng 0.

V d, mt phn t dn c th c m hnh ho bng cch t J=i33=i22=0, cn phn t

thanh phng c m hnh ho bng cch t j=i22=0 ; as2=as3=0, to ra bin dng ct theo phng ngang bng 0. cng ct theo phng ngang b b qua nu cng un

tng ng bng 0.



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2.3.1.3. Cc loi mt ct ngang

khai bo mt ct ngang cho phn t thanh c th dng mt trong cc cch sau:

- Khai bo trc tip gi tr ca cc i lng a, j, i33, i22, as2, as3 tnh t kch thc ca mt ct, lc ny chn tham s SH = G (vo general) .

- i vi cc loi tit din mu nh hnh ch nht (R), hnh ng ( P ), ...nh trong bng (hnh 3.19), chng trnh s t tnh cc gi tr ca a,j, i33, i22, as2, as3 t cc kch

thc ti thiu m ngi dng khai bo. Trong trng hp ny chn cc tham s SH l mt trong cc ch R, P, B, I, C, T, L, 2L .

- Chng trnh SAP2000 cung cp cc file c s d liu l cc tit din mu, kt cu thp theo cc tiu chun ca Anh, M, chu u sn xut trong nh my. Cc tit din ny c sn kch thc nm trong cc tp. Nu chn tit din t cc file ny th cc i

lng a, j, i33, i22, as2, as3 cng c chng trnh tnh ton t ng. Cc tp c s

d liu c sn ca SAP2000 bao gm :

+ AISC.PRO : cc dng kt cu thp theo tiu chun ca M.

+ CISC.PRO : cc dng kt cu thp theo tiu chun ca Canaa.

+ SECTIONS.PRO : l mt bn sao ca AISC.PRO.

Ngoi cc tp c sn trong chng trnh, cng c th t to ra cc tp cho ring tng

ngi dng t chng trnh PROPER .

Cc gi tr c trng hnh hc ly theo h n v khai bo khi nhp d liu (DL), v c th chuyn i t ng cc h n v trong qu trnh nhp DL ca SAP2000.

Mi dng tit din lu tr trong tp c s d liu c th m t di mt hoc hai nhn (tn)

khc nhau. V d, nhn W36x300 trong tp AISC.PRO c th biu th bng nhn W36x300 hoc nhn W920x446, cc nhn ny ct trong mt tp ring c ui . LBL.

Tt c cc tp c s d liu cho cc c trng mt ct ngang phi t trong th mc ang

cha tp d liu vo (tp cha cc m t kt cu hoc s ), hoc trong th mc cha chng trnh SAP2000. Nu trong c hai th mc ny u c tp c s d liu th chng

trnh s u tin nhp tp CSDL trong th mc cha tp d liu kt cu .

2.3.2. Khai bo cc tit din trong SAP2000 Define Frame/Cable/Tendon Section

C th dng mt trong cc kiu khai bo sau :

- Gi cc tit din c sn trong cc tp th vin ca SAP : Define Frame/Cable Section Import Wide Flange( ch dng cho vt liu thp, thit k theo chun ca M- AISC, Canada -CISC, Anh . . . v sn xut trong nh my ) bng cch chn cc



157

tp *.pro sau chn nhm thp (thp gc, hnh ch L,T . . . ) v cui cng chn tit din (kch thc c th) trong trng hp ny khng phi khai bo kch thc tit din .

- Chn mt trong s cc tit din c hnh dng thng dng SAP c sn nh tit din ch nht, trn, T, U, C . . .( hnh 3.19), trong trng hp ny ch cn khai bo mt s kch thc ti thiu nh chiu cao, rng . . .m SAP yu cu. Tu theo kch thc a

vo m c cc dng hnh hc khc nhau. khai bo cho cc tit din ny vo : Define Frame/Cable Section Chn Tn TD

Sau y l mt s dng hnh hc :

Hnh 3.19



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- Khai bo mt tit din bt k khng c sn trong SAP (dng chc nng User trong Choose property Type Add), ngi dng phi tnh sn v a vo cc gi tr c trng Tit din nh din tch ,mmen qun tnh . . . ( A, I22, I33, J . . .).

- Ngi dng cng c th to ra th vin ring cho mnh vi cc loi tit din mi.

V d 1: khai bo mt tit din dm b tng ch nht c kch thc 0.5 x 0.25(m), cc bc thc hin( hnh 3.17):

- Chn n v sao cho chiu di l m.

- Vo Define Frame Property Add Rectangular ( trong mc Add Wide Flange) Add New Property nhp cc gi tr :

+ Section name : DAM1

+ Material : CONC

+ Dimension : t3 = 0.5 ; t2 = 0.25 OK

V d 2: khai bo mt tit din thp hnh vnh khuyn (ng) ng kch 0.3(m), dy

ng l 2cm, cc bc thc hin ( hnh 3.18):

- Chn n v sao cho chiu di l m.

- Vo Define Frame Property Add Pipe( trong mc Add Wide Flange) Add New Property nhp cc gi tr :

+ Section name : ONG

+ Material : STEEL

+ Dimension : t3 = 0.3 ; tw = 0.02

+ OK

2.3.3. Cch khai bo mt s tit din c bit

2.3.3.1. Phn t Frame tit din Non- Primastic

y l kiu phn t c tit din thay i theo

chiu di trc thanh, trong mt thanh c th

c nhiu on tit din thay i, trong ,

mi on phi bin i theo qui lut tuyn

tnh hoc cc dng parabon bc 2, bc 3.



159

Hnh 3.20

Trc khi khai bo cho Non- Primastic, ngi dng phi khai bo trc t nht hai loi tit

din.

Cch khai bo :

- Vo Menu Define\Frame Section

- Add Non-primastic, m hp thoi (hnh 3.20)

- Non-primastic Section name : t tn

cho loi tit din ang khai bo

- Khai bo tng on ca thanh :

+ Chn Start section name:chn tn

ca tit din u

+ Chn End section name: chn tn

ca tit din cui

Hnh 3.21

+ Nhp Length: Chiu di on c tit din thay i

+ Chn kiu bin i tit din

trn mt on: Variable( chiu di tng i); Absolute (gi tr chiu di)

+ Chn kiu thay i EI33

+ Chn kiu thay i EI22

+ Chn Add, insert, modify hoc delete thm, chn, bin i hoc xa cc thng tin va khai bo cho tng on > nhn OK

Trn hnh 3.19 v 3.20 l cch m t cc loi tit din gn cho phn t thanh khung 2 tng, 2 nhp:

+ Tit din C1 ( trn c Circle ) : ng knh 0.5 m

+ Tit din C2 ( trn c Circle ) : ng knh 0.2 m

+ Tit din R1 (hnh vung-Rectangular ) : cnh 0.4 x 0.4 m

+ Tit din R2 (hnh vung-Rectangular ) : cnh 0.2 x 0.2 m

+ Tit din TDTD( thay i Nonprimastic) : c 3 on : m t nh trn hnh 3.21



160

2.3.3.2. Phn t Frame tit din General

L phn t m kiu tit din khng c trong cc kiu mu sn ca Sap, do vy phi tnh t

ngoi cc c trng hnh hc nh A: din tch tit din, I: mmen qun tnh, J: mmen

xon . . . v a vo hp thoi ca chng trnh. Loi kt cu ny thng dng trong bi tp c hc kt cu m tit din l t hp ca nhiu tit din c bn. Tnh kt cu khng

quan tm n chuyn v cng c th dng cch khai bo ny .

Cch khai bo :

- Vo Menu Define / Frame Section

- Nhn Add General m hp thoi v

- Nhp cc gi tr ca :

+ Corss Section (Axial) Area : Din tch tit din

+ Tosional Constant: M men xon

+ Momen of Inertial About: m men qun tnh quay quanh (3 =trc3; ...)

+ Shear Area: Din tch ct

+ Section Modulus About Axis: M men chng un

+ Plastic Modulus About Axis: M men do

+ Radius of Gyration About: Bn knh qun tnh

+ Tr ra mn hnh khai bo tit din, chn

- Material Name : tn vt liu OK

2.3.3.3. Phn t Frame c tit din AutoSeclect

Auto Select l mt nhm cc tit din khai bo trc v c t tn. Kiu nhm

ny gi l Autoselect. Thng dng vi kt cu thp & tnh cho bi ton ti u ho tit

din (Optimazation) .

khai bo loi ny cng phi c t nht hai

loi tit din khai bo. Trnh t thc hin:

- Vo Define / Frame Section

- Chn Add Auto Select : to nhm mi

- Nhn Add New property, hin hp thoi

- Auto Section name : nhp tn nhm Hnh 3.22



161

- Chn cc section khai bo trong List of Section, a vo danh sch ca Auto select bng cch Add

( a vo nhm) hoc Remove( xa khi nhm). Tn ca tit din s hin trong hp

Auto Selections

- OK.

2.4. V phn t Draw Draw Frame /Cable

chn chc nng v cc phn t thanh, c th gi lnh t thanh menu Draw hoc t

biu tng trn thanh cng c :

- C th v phn t thng thng hoc v nhanh (Quick Draw)

- Nn thng nht hng ca cc phn t trong qu trnh v ( t di ln trn v t tri qua phi )

- Tn dng cc chc nng bin i i tng nh copy, move, delete,device,replicate trong qu trnh to phn t .

c th hin c cc s hnh hc ca kt cu to, dng cc chc nng :

- 3D View ( hin s theo khng gian 3 chiu )

- 2D XY, XZ . . . ( hin tng mt phng)

- Nu c h li, c th di chuyn mt phng theo cc dng li qua chc nng

- hin kt cu cc thnh phn ca kt cu theo mt s thng s ci t dng View Set Display Option

V d: cho hin kt cu vi tn ca phn t v dng khi nh hnh 3.21 : chn View Set Display Option Label ( trong Frame/ Cable) v Extrude view (hoc Shade Option) trong General.

- xem cc thng s ca phn t hay nt ang hin trn mn hnh, nhn vo i tng v chut phi .

2.5. Gn tit din cho phn t Assign Frame/Cable /Tendon Frame Section

Trong chng trnh SAP2000, khi v phn t, chng trnh cho php ngi dng chn mt

trong cc tit din khai bo hoc t mc nh mt tit din no (FSEC1,w18x35).

Nu cc tit din do chng trnh t ng gn khng ng vi yu cu, ngi dng phi



162

gn li cc tit din. gn tit din cho mt hoc mt nhm phn t trong kt cu, thc

hin cc bc sau:

- Chn cc phn t mun gn dng cc chc nng trn thanh cng c hoc bng mt trong cc chc nng ca Select

- M hp thoi : Assign Frame/Cable /Tendon Frame Section

- Chn tn tit din cn gn ( c ) trong danh sch bn tri OK

Cc chc nng la chn ca Select bao gm :

+ Chn tng phn t, chn theo ca s - Pointer/Window

+ Chn theo ng thng i qua cc phn t - Intersecting Line

+ Chn theo tn cc tit din - Section

+ Chn theo cc nhm ( Group) khai bo- Group

+ Chn theo tng mt phng XY ( XZ,YZ) Plane

+ Chn theo tn i tng Label

Trong qu trnh chn phn t c th kt hp vi Deselect ( chc nng loi b cc phn t chn) c hiu qu nhanh hn.

2.6. Khai bo lin kt Assign Joint Restraint

Trong chng 1 trnh by kh k cc khi nim

v lin kt trong s kt cu. Khai bo lin kt

qu trnh to lp m hnh kt cu l khai bo cc lin

kt ni t m bo cho kt cu khng bin hnh,

khng mt n nh ... bng cch gn cho cc bc t

do ca nt cc lin kt cng (Restraint) hoc lin kt

n hi (Spring).

gn cc lin kt cng thc hin cc bc: Hnh 3.23 Khai bo lin kt cng

- Chn cc nt cn gn lin kt ni t

- M hp thoi Assign Joint Restraint



163

- Chn mt trong cc biu tng (icon) ca Fast Restraints c loi lin kt cn gn (ngm, gi c nh, gi di ng) hoc nh du vo cc v tr c bc t do khng

chuyn v.

- OK

2.7. Khai bo cc trng hp ti trng : Define Load case

Trng hp ti trng (Load Case) l cc phng n ti khc nhau, c lp, t c th d dng a vo cc t hp ti trng. Trng hp ti trng (THTT) c th chia nh tu ,

mi trng hp c h s ring i vi ti trng bn thn (Self Weight Mutiplier), mc nh

ca SAP2000 l 1cho loi ti trng tnh (DEAD) .

Khi tnh ton, theo mc nh, SAP s tnh v cho kt qu ca tt c cc trng hp TT

khai bo. Ngi s dng c th hn ch (chn) nhng trng hp cn tnh trong hoc Analyse Set Analyse Case to Run trc khi phn tch kt cu.

Hnh 3.24 Khai bo cc THTT

Ch trong cc trng hp ti trng, ch nn khai bo mt trng hp l c h s Selft Weight 0.

Cc bc thc hin (Static load cases) :

- Vo Menu Define / Load case v chn (hoc nhp) cc thng s :

+ Tn trng hp ti: Load Name

+ Kiu tI trng (type): Dead (Tnh ti) ; Live (hot ti); Wind (Gi), Snow(tuyt) ; Quake (Ti trng tnh do ng t)

Nu t hp theo TCVN th cc la chn ny khng quan trng.

+ Sefl weight: h s tnh trng lng bn thn cho mi phn t c mt trong kt cu Nu cho SW = 0 th khng tnh trng lng bn thn trong trng hp ny.

+ Delete : Xa mt TH tI trng, s xa cc gi tr lc gn cho phn t .



164

V d : Khai bo 4 trng hp ti trng ( nh hnh 3.24):

- LOAD1 : type DEAD, h s trng lc ( bn thn ) = 1.

- LOAD2 : type LIVE h s =0

- LOAD3: type WIND, h s = 0

- LOAD4: type OTHER, h s = 0

2.8. Gn ti trng cho phn t ca tng trng hp ti trng

Trong cc phn mm tnh kt cu, ti trng gn cho cc nt hay phn t ti mt thi im

ch c gn cho mt trng hp TT (Load Case) c th khai bo trc. Qu trnh gn

ti trng cho cc phn t tun theo cc bc sau :

- Chn cc phn t cn gn (dng cc chc nng ca Select)

- Chn loi ti trng cn gn trong Assign ( Joint Load hoc Frame/Cable/Tendon Load), m hp thoi, thc hin cc thao tc :

+ Chn loi ti trng

+ Chn hng ti trng ( theo trc no ca Global hay Local )

+ Kim tra trng thi gn (Option) trong check box ( add, replace hay delete )

+ Chn trng hp cho ti trng ang gn

+ a vo gi tr ca ti trng trong hp thoi.

Sau y s trnh by mt s loi ti trng thng gp trong kt cu h thanh :

2.8.1. Ti trng bn thn :

Ch cn khai bo h s Mutiplier trong Load Case ( ch phi khai bo gi tr chnh xc

ca trng lng bn thn W trong Define >Material ).

- Selft Weight : l h s tnh ti trng bn thn p dng cho mi phn t trong kt cu. N tnh trng lng bn thn theo phng -Z v lun c gi tr dng .

- Gravity : l h s tnh ti trng bn thn p dng cho mt s phn t nht nh trong kt cu chn,c th c cc phng X,Y,Z . Nu theo phng -Z th c gi tr m .

+ Ti trng tp trung ti nt : hp thoi khai bo ti trng trn hnh 3.25:

Assign Joint Load Force

+ Ti trng tp trung trn phn t : hp thoi khai bo ti trng trn hnh 3.26:



165

AssignFrameLoad Point

Hnh 3.25 Hnh 3.26

2.8.2. Ti trng phn b trn phn t (Assign Frame load Distributed )

Trong SAP2000 mi phn t ch c php gn ti a 4 ti trng tp trung trn phn t hoc 4 im c gi tr ti trng khc bit (i vi ti trng phn b khng u), do vy

trong hp thoi ch c 4 ct vo cc gi tr cho cc khong cch ti cc im t lc

(Distance)- tnh n u thanh v gi tr lc ti tng im ( Load ). Cu trc ca hp thoi ny cng ging nh hp thoi cho lc tp trung trn phn t hnh 3.26.

Khi vo gi tr cho cc khong cch (distance) c hai cch :

Hnh 3.27 Mt s loi ti trng phn b trn phn t thanh ca SAP2000



166

- Nu chn Relative Distance from end I : th cc gi tr ny l t l ca khong cch tnh t im t lc n u thanh /chiu di c thanh. V d distance = 0.5 l im gia thanh.

- Chn Absolute : l gi tr thc ca di t im t lc n u thanh. V d distance = 0.5 l im t lc cch u thanh 0.5 m.

xem cc ti trng gn vo Display Show load (chn Joint, Frame, Shell) c th xem cho tng trng hp ti trng ca tng loi, hin hnh dng hoc gi tr. Ring ti trng m men s hin di dng ngu lc .

cc v d khai bo ti trng trn phn t thanh

V d 1

0.5T 1T 0.8T

I J

1.2 m 2.5 m

4.5 m

6 m

Cch khai bo :

V tr 1 2 3 4

Distance (m) 1.2 2.5 4.5

Load ( T ) 0.5 1 0.8

Chn Absolute

V d 2 0.8T

I J

1.2 m 2.5 m

6 m

Cch khai bo :



167

V tr 1 2 3 4

Distance (m) 1.2 3.7

Load ( T ) 0.8 0.8

Chn Absolute

V d 3

1.2 T

I 3.0 m J

6 m

Cch khai bo :

V tr 1 2 3 4

Distance (m) 0 0.5 1

Load ( T ) 0 1.2 0

Chn Relative

V d 4 1.2 T

I 1 m 1.3m 2 m J

6 m

Cch khai bo :

V tr 1 2 3 4

Distance (m) 1.0 2.5 4.5

Load ( T ) 0 1.2 0

Chn Absolute



168

V d 5 1T

0.8T

I J

4.5 m

6 m

Cch khai bo :

V tr 1 2 3 4

Distance (m) 0 0.75 0.75 1

Load ( T ) 1 1 0.8 0.8

Chn Relative

V d 6 1T

0.5 T

I J

1 m 2.2 m 1.8 m

6 m

Cch khai bo :

V tr 1 2 3 4

Distance (m) 1. 3.2 3.2 5.0

Load ( T ) 1 1 0.5 0.5

Chn Absolute

V d 7 1T

0.8T 0.5T 0.7T

I J

1.2 m

2.5 m

4.5 m

6 m



169

Cch khai bo :

V tr 1 2 3 4

Distance (m) 1.2 2.5 4.5 6.0

Load ( T ) 0.8 1 0.5 0.7

Chn Absolute

2.9. T hp ti trng

T hp ti trng l cc phng n ti cn tnh trong thc t (xut ra kt qu) da trn cc

trng hp ti trng khai bo. Trong mi t hp ti trng c th xp nhiu trng hp

ti mt lc v mi THTT c th c h s t hp khc nhau .

2.9.1. Cch khai bo t hp :

- Khai bo tn t hp: (R C Name)

- Chn phng php t hp (Type)

- Khai bo cc trng hp tham gia trong t hp:

+ Chn tn cc trng hp (Case Name)

+ a vo h s t hp cho tng trng

hp TT tham gia trong t hp ny (Scale)

+ Nhn Add

- OK kt thc khai bo mt t hp.

Hnh 3.28 Hp thoi khai bo t hp TT

2.9.2. Cc i lng trong t hp ti trng(Load Combination):

- Tn t hp: Combo Name

- Kiu t hp cc gi tr: (Type)

+ Add : t hp theo PP cng tc dng;

+ Enve : Bao ni lc;

+ SRSS: Cn bc 2 ca tng cc bnh phng THTT

+ ABS: tr tuyt i cc trng hp ti

- Scale factor : H s t hp, tc l h s ca tng trng hp ti trong t hp



170

V d v h s cho mt s t hp c bn (THCB) v t hp c bit (THB) theo Tiu

chun TCVN 2737-95 :

+ THCB1: 1 TH di hn + 1 TH ngn hn nguy him nht

+ THCB2: 1 TH di hn + 0.9 TH (nhiu trng hp ngn hn)

+ THB1 : 1 TH di hn + ? x ngn hn + ? x c bit( tu trng hp c th )

+ THB2: ngn hn khng k tI trng gi

2.10. Hng dn mt s v d tnh khung

Cc phn trnh by l thuyt trong ti liu ny, chng ti da theo cc phin bn gn y

ca SAP2000 (t phin bn 9.03) bn c c nhng thng tin mi, bn cnh chng

ti cng phn tch v lu s khc nhau trong mt s phn gia SAP2000_V7.4 v cc phin bn sau. Tuy nhin trong cc v d hng dn thao tc phn ny, chng ti ch

yu hng dn theo SAP2000V7.4 l phin bn sinh vin ang hc v thc hnh trn

phng my. Ti nhng cu lnh m cch thc hin gia hai phin bn c s khc nhau, chng ti gii thiu c phin bn SAP2000_V9.03 trong phn ngoc n bn c tham kho.

2.10.1. V d tnh khung phng (hnh 3.29)

2.10.1.1. S liu

P1 Vt liu b tng (kg-cm):E=2.56x105; W=2.4x10-3

Tit din: Ct = 30x30 cm; Dm = 30x 22cm

Thanh xin = 25x25 cm

3.5 m q1 q1 =0.8 T/m ; q2 = 1.1T/m ; q3= 1.4T/m

P2 q4 = 0.6 T/ m; P1 = 1.2 T; P2 = 1.3 T

* Trng hp 1 : Chu ti trng

3.5 m q2 q3 bn thn, ti trng q1, q2 v P1

*Trng hp 2:Chu cc ti

trng q3, q4 v P2

4m q4 * Lin kt ngm chn ct

4m 4m 3m

Hnh 3.29



171

Hnh 3.30 S hnh hc v b tr ti trng trong TH1 v TH2

2.10.1.2. Trnh t thc hin :

2.10.1.2.1. Thit lp s hnh hc :

- Chn n v Kg- m

- To h li - trong mt phng XZ :

+ Vo New Model ( New Modal Grid Only ), chn h mc nh Cartersian

+ G cc gi tr ca Number Grid Spaces ( Number of Grid Lines) :

X=3 (4) ; Y=0 (1) ; Z=3 (4)

+ G cc gi tr ca Grid Spacing : X=4 ; Y=1 ; Z=3.5

mn hnh 2 ca s, chn mt ca s l mt phng XZ : trn mn hnh xut hin h li

cch u nhau theo cc khong khai bo. Ch , i vi SAP2000 V7.4, h trc nm

gia h li, cn V9.03, h trc nm mp tri bn di .

iu chnh h li va to cho ph hp vi s kt cu : (xem hnh 3.29 v 3.30)

+ Define Coordinnate Grid ( Define Coordinate System/ Grids)

+ Nhn Draw Edit Grid chn trc X



172

+ nh du vo dng li c to X l 6 (12), sa li thnh 5 (11), nhn Move Grid Line OK

+ Nhn Draw Edit Grid chn trc Z

+ nh du vo dng li c to Z l 0, sa li thnh -0.5, nhn Move Grid Line OK.

Hnh 3.31 Bin i v tr li theo trc X

theo SAP2000_V7.4(trn), V9.03 (di)

Hnh 3.32 Bin i v tr li theo trc Z

theo SAP2000_V7.4(trn), V9.03 (di)

V cc phn t thanh ca s kt cu : Nhn vo biu tng ca Frame hoc vo Draw Draw Frame Element v ln lt v tng thanh theo s kt cu ( ch theo trnh t t di ln v tri sang phi, dng phm Enter ngt mi qu trnh v ).

2.10.1.2.2. Khai bo vt liu v tit din :

- Chn n v l Kg - cm

- Nhn Define Material Add new Material : a vo gi tr ca E (m un n hi), W (trng lng ring) v M (khi lng ring) v g ch BETONG Material Name

- Khai bo cc tit din :

Nhn Define Frame Section Add/Wide

Flange Add Rectangular (Add new property) :

+ G tn tit din Section Name = COT

+ Chn loi vt liu Material = BETONG Hnh 3.33



173

+ Khai bo kch thc t3 = 30 t2= 30

+ Lm tng t vi tit din DAM (hnh 3.33) v XIEN.

2.10.1.2.3. Gn tit din cho cc phn t :

- Chn cc phn t ct (dng ca s hoc nh du chn)

- Vo Assign Frame Section chn tit din tn COT OK

- Tng t chn cc phn t dm gn cho tit din DAM v phn t mi gn cho XIEN

2.10.1.2.4. Gn lin kt

- Chn 4 nt chn ct : Vo Assign Joint Restraint chn biu tng ngmOK

- Gn lin kt khp cho cc thanh xin :

+ Chn 2 thanh xin

+ Assign Frame Release nh du vo 2 Start

v End ca Mmen M33 OK ( Hnh 3.34)

+ Chn ct chng gia Assign Frame Release

nh du vo End ca Mmen M33 OK

Hnh 3.34

( Ch ct d liu vo a: File Save As Khai bo tn th mc v tp OK)

2.10.1.2.5. To cc trng hp ti trng :

- Define Static Load Case g TH1 Add new Load OK

- Define Static Load Case g TH2 h s Selft Weight Multiplier = 0 Add new Load OK

2.10.1.2.6. Gn ti trng cho tng trng hp

(Chn n v Ton m)

Trng hp 1 :

- Chn 2 phn t dm tng 2 chu q1 :

- Assign FrameStatic Loads

Point and Uniform (Distributed Loads) OK

+ Load case Name = TH1

+ Direction = Global Z ( Force )



174

+ Option : Add to Existing Load

+ Uniorm Load = -0.8 OK (hnh 3.35)

Tng t vi 2 thanh dm chu q2 = - 1.1 T/m

- Gn TT cho nt nh : + Chn nt nh

+ Assign Joint Static Loads Forces


+ Option : Add Exiting Load

+ Load = Force Global Z = -1.2 OK

Hnh 3.35

Trng hp 2 :

- Chn phn t dm( nh 1 tng )

- Assign Frame Static Loads Trapezoidal (Distributed Loads) (hnh 3.36)


+ Direction = Gravity ( Force )

+ Option : Add to Exiting Load

+ Absolute Distance End I

Distance 0 3

Load -1.4 0 OK

Hnh 3.36

- nh du 2 ct tri ngoi cng :

- Assign Frame Static Loads Point and Uniform (Point) OK


+ Direction = Global X ( Force )

+ Option : Add to Exiting Load

+ Uniorm Load = 0.6 OK

- Gn TT ti nt P2 : Chn nt gc trn bn tri

+ Assign Joint Static Loads Forces

Hnh 3.37



175


+ Option : Add Exiting Load

+ Load = Force Global X = 1.3 OK ( hnh 3.37, ch xo gi tr c ca Global Z)

2.10.1.2.7. Tnh ton :

- Khai bo s lng cc mt ct cn tnh ton trn mt phn t

+ Chn cc phn t

+ Assign Frame Output Segment :

g s lng mt ct cn a ra kt qu

(c th khc nhau trn tng thanh )

- Analyze Set Option

Chn biu tng ca XZ Plane

- Chn Generate OutputSelect Output Options

nh du cc thnh phn s in trong tp kt qu *.OUT

( v d Displacement , Frame Force . . . ) OK Hnh 3.38

- Nhn nt Run ( ) thc hin tnh ton

2.10.1.2.8. X em kt qu

Vo Display Show Deformed Shape: xem Biu chuyn v (hnh 3.39) v

Show Forces Stress xem biu m men.

Hnh 3.39



176

2.11. Mt s phn nng cao

C th tham kho thm cc chc nng ca phn ny chng 2 Giao din ha ca SAP2000.

2.11.1. To nhm - Group

- Nhm l mt chc nng mi ca SAP, cho php ngi s dng a mt s phn t c cng c im no , gp li vi nhau v t mt tn. khai bo nhm phi qua

hai bc t tn nhm v nh du cc phn t gn cho nhm. C th dng mt trong hai cch sau:

+ Cch 1: Bc 1 : Khai bo tn ca nhm trong Define Group ; Bc 2: nh du cc phn t ca nhm, vo Assign Assign to Group v chn tn khai bo.

+ Cch 2 : Bc 1: nh du cc phn t thuc nhm sp khai bo; Bc 2 : vo Assign Assign to Group Add new Group v a vo tn nhm.

- Nhm c th c s dng trong qu trnh chn phn t, gn vt liu, gn ti trng . . .

- Cc nhm c th nm trong nhau (trong G2 c th c G1 v mt s phn t khc).

- Dng nhm trong nhiu trng hp rt tin li khi cn chn hoc loi b mt s phn t, gip ngi dng thao tc nhanh khi thit lp s kt cu.

- Nhm sau khi khai bo c th s dng tn nhm trong cc thao tc la chn gn tit din, ti trng,. ..

- Cc phn t trong cng mt nhm c th ging nhau mt s thuc tnh hoc tt c cc thuc tnh ty theo la chn ca ngi dng khi to nhm.

2.11.2. Cc cch bin i i tng EDIT

Hu ht cc lnh trong phn ny nm trong menu Edit.(Tham kho thm phn ny trong

chng 2).

- Lnh COPY sao chp i tng gc (mu) thnh mt i tng mi di chuyn so vi i tng mu

(trc ) theo c 3 phng ( Dx, Dy, Dz). Cch thc hin:

+ Chn nhm i tng mu .

+ Nhn Edit Copy (Ctrl + C).

+ Nhn Edit Paste (Ctrl + V).

Hnh 3.40

+ Nhp cc gi tr di chuyn (Delta) trong khung Change coordinate by (Hnh 3.40)



177

OK.

- Lnh Move c tc dng i vi nt v phn t :

+ Nu chn nt : cc phn t dnh vi nt u b ko theo n v tr mi, dng v kch thc ca phn t b thay i theo.

+ Nu chn phn t : lnh c tc dng tnh tin nhm phn t, kch thc PT khng thay i.

+ C th chn nhiu i tng trong lnh v cch thc hin ging nh lnh Copy.

- Set Reshape Mode thay i dng ca phn t qua vic nh du i tng, ko l phn t n v tr mi.

- Replicate : (Linear , Miror, Radial) : Edit Replicate Linear/Mirror/Radial

y l cc lnh sao chp i tng theo nhiu cch khc nhau.

Cc bc thc hin vi cc lnh ny :

+ Chn i tng gc.

+ a vo cc khong cch di chuyn theo cc phng X,Y,Z (vi lnh Linear) hoc khai bo trc quay (trc i xng) vi lnh Radial v v tr mt phng i xng (vi

Mirror) .

+ Khai bo s i tng mun to thm (Number).

Vi Linear : c th sao chp thnh nhiu i tng mi vi cc bc di chuyn theo mt hoc c 3 trc X,Y,Z theo cc khong cch bt k khai bo.

V Radial : qu trnh sao chp thnh cc i tng mi qua vic quay cc i tng mu quanh mt trc no vi gc quay bt k (vi sap 7 ch quay c quanh gc ta ).

Vi Mirror : to cc i tng mi dng kh nng i xng qua mt mt phng, cng c th khai bo trc Mirror qua hai im bt k.

Hnh 3.41 Hp thoi cho cc chc nng ca Replicate : Linear-Radial-Mirror

c im ca cc lnh trong Replicate :



178

- C th sao chp i tng theo nhiu cch khc nhau, t SAP2000_V.8 c th ch la chn mt s hoc tt c cc thuc tnh ca i tng gc khi sao chp (v d ch sao chp kch thc hoc kch thc v mt s thuc tnh khc nh Section, Release,

Regid , Load . . .) khi thc hin lnh.

- Sau khi sao chp c th gi li i tng gc hoc xo i ( Delete original Objects ).

- Vi chc nng Radial , Mirror :

+ C th chn trc sn c lm trc quay ( dng parallel X,Y,Z )

+ hoc khai bo trc quay mi qua hai im trong khng gian (3D- Rotate,3D Line, 3D Plane, v a vo to X,Y,Z ca hai im ny).

+ hoc a vo mt im xc nh trc quay trong mt phng ca hai trc kia (v d quay quanh trc X chn Rotate axis ( X) Coordinate Points on YZ Plane.

+ Nn dng chc nng to h to mi (trt gc to ) xc nh trc quay trc khi dng lnh s hiu qu hn.

2.11.3. Ghp thm mt kt cu mi vo kt cu c: Edit Add to Model from Template

S dng chc nng ny ngi dng c th ghp thm cc kt cu c

trong thvin mu ca SAP vo s

ang thit lp .

Mi h ghp mi c th c h ta

, h liv loi kt cu ring.

Cch thao tc :

+ Menu Edit Add Model Template:mn hnh s hin

bng th vin mu nh New Model. Cc khai bo cng

ging nh New Model

Hnh 3.42

+ Ch khai bo v tr chn (so vi h Global) .

+ Mi h ta ca kt cu mi s l mt h ta con.

Hnh v 3.42 minh ha cho cc thao tc : T New Model, to mt khung phng 2 tng, 2 nhp, sau vo Edit Add Model Template gi th vin mu ca dn v khai bo mt dn phng trn nh khung. Tham kho v d 5 ca phn 2.11.5



179

2.11.4. To h to con : Define Set coordinate System/Grid

H to con (h ta ph) gip cho ngi s dng mm do trong qu trnh thit lp

s kt cu. H ta con c mt s c im sau:

- Mi h to con c th c khai bo tn, n v, h li ring cho mnh.

- Cc tham s chuyn trc khi khai bo trong Edit Grid hoc Advance (v tr mi ca h trc ta con) l lun so vi h to tng th (Global) ch khng theo h to hin thi .

- C th hin kt cu trong tng h to con (i khi ch mt phn ca kt cu c hin) qua vic chuyn i gia cc h ta qua GLOBAL ca thanh trng thi (gn khai bo n v) hoc vo Define Coordinate System/Grid .

- Khi thit lp s kt cu trong h ta con, cc gi tr to l so vi h to con ang s dng. Trnh t thao tc khi thit lp h ta con:

- Define Coordinate System /Grid (hoc Option/ Coordinate System) Add New System m hp thoi New Coord Grid System (hnh 3.43 tri). Trong hp thoi ny

ngi dng s khai bo h li cho h ta con. Cch khai bo cng nh h h Global.

- Nhn vo Edit Grid (hnh 3.43)Location System Origin hin hp thoi Coordinate System (hnh 3.44), ngi dng a vo cc tham s khai bo v tr ca h ta con so vi h tng th.

Tham kho v d 6 phn 2.11.5

Hnh 3.43 Hnh 3.44



180

2.11.5. .Mt s v d dng cc lnh ca EDIT

1 . To mt dn khng gian chp phng 2. To nh 2 tng,3 nhp, 2 nhp c

mi dc

+ To lp mt dn chp 10 x 5(m) + Chiu rng mi nhp theo X 5m

+ Mi chp l mt khi lp phng 1x1(m) + Chiu rng mi nhp theo Y l 4m

+ C cc thanh ni dc, ngang gia cc nh chp + Chiu cao tng 3.5 m, mi dc 1m

3. To xil hnh chp ct 4. To cu dy vng

+ C Ry=8m, Rmt=6m ,cao 10m + Di 40m,tr cao 15m rng 5m

+ C 10 dy treo trn mt cu

5. To mt khung li ct , v mi 6. To khung vm

+ Khung 4 nhp rng (Y) 6m, + Khung rng 10m cao 4m

cao 6m di ( X) 15m + Vm cong R=6.5m

+ Vm c R=4.5, gc m 42 o



181

Vi cc phin bn SAP khc nhau, b cc v qui nh trong cc menu v hp thoi c s

khc nhau. Trong phn minh ha cho cc lnh ca Edit, ti liu hng dn trnh by theo

2 phin bn bn c tin theo di, tham kho.

2.11.5.1. Hng dn cc bc thao tc cho 6 v d trn bng SAP2000V.7.4 :

V d 1 :

+ To mt khi lp phng c kch thc cc cnh =1m ( dng h li Decac vi tt c cc tham s =1).

+ V mt chp trong khi lp phng (to mt im gia mt trn khi LP lm nh chp).

+ Vo Edit Replicate Linear : theo phng X,nhp : Distance =1, Number = 9, lm tng t vi phng Y(1, 4).

+ Ni cc phn t gia cc chp theo phng X, phngY (v mt phn t thanh,chia nh hoc c th dng Linear to cc phn t ni).

V d 2:

+ Gi th vin mu khung 2 tng, 3 nhp : FileNew Modal Templace chn Space Frame, a vo cc tham s cho kt cu nh trong u bi.

+ Chn 6 thanh nhp 1 v 3 tng 2, chia i (dng device frame).

+ Chn cc nt gia cc thanh va chia, di chuyn ln ln 1m (bng lnh Move).

V d 3:

+ Chn h to tr vi cc tham s : ( R , q , Z : 4,36,1 / 2,10,10 ).

+ V mt phn t tam gic cho y b, chia thnh 3 phn t nh .

+ Dng Radial cho kn y nhp tham s : ( 35-10 ).

+ nh du 2 nt pha trn, v mt phn t nghing, chia thnh 5 phn t.



182

+ Dng Radial sao chp phn t ban u to thnh b.

V d 4 :

+ To h li trong mt phng XZ (1 khong theo phng X v 3 khong theo phng Z).

+ V 1 thanh thng theo phng X dng li th 3, chia thnh 10 on.

+ V tr cu theo phng Z pha trn 1/3 (to 2 im nt theo phng Z), chia thnh 3 on. V cc dy cp pha tri cu .

+ nh du cc dy cp va v, vo Edit Replicate Mirror : chn mt phng = YZ , Ordinate X=0.

+ Chn All , Mirror trong mt phng XZ, Ordinate Y=2.5

+ V tip 2 dm 2 u cu

V d 5 :

+ Gi th vin mu khung 1 tng 1 nhp FileNew Modal Templace chn Space Frame: (1,1,1,6,15,6)

+ Gi th vin mu ( Edit Add Temp Barrel vi cc tham s : ( 6, 15, 15, 4.5, 42), chn tip Advance : nhp Distance Z=6, b restraint.

V d 6:

+ V khung phng 1 tng,1 nhp 10m, cao 4m, xo 2 thanh ngang.

+ Chn h trc ta mi: Option Set Coordinate System Add System Cylindrical & a vo cc tham s : 1,36,0,6.5,10,0 vo Advance Rotate X=90

+ V cc on thng ni gia khung v ng cong bng frame .

+ Chuyn v h ta Global , XZ

2.11.5.2. Hng dn cc bc thc hin 6 v d trn theo SAP2000V.9 :

V d 1 :

+ To khi lp phng 1,1,1(m) : New Modal Grid Only chn Catersian v nhp cc tham s = 2,2,2,1,1,1

+ V mt chp trong khi lp phng (to mt im gia mt trn khi LP lm nh chp, v cc thanh y v xin ca chp) ( hnh 3.45)

+ Vo Edit Replicate Linear : theo phng X : Distance =1, Number = 9 , Ni cc phn t gia cc chp theo phng X (hnh 3.46)



183

+ Tng t vi phng Y(distance Y= 1, number=4 ) (hnh 3.47)

+ C th dng linear ni cc nt cc thanh theo phng Y gia cc nh chp.

Hnh 3.45 Hnh 3.46 Hnh 3.47

V d 2:

+ Gi th vin mu khung 2 tng, 3 nhp: File New Modal 3DFrame

+ Chn Open Frame Building, a vo cc tham s kch thc khung nh trong u bi.

+ Chn 6 thanh nhp 1 v 3 ca tng 2, chia i (dng device frame ) (hnh 3.48)

+ Chn cc nt gia cc thanh va chia, di chuyn ln trn 1m (lnh Move)(hnh 3.49)

Hnh 3.48 Hnh 3.49

V d 3

+ V cc phn t t gic v tam gic cho y b (hnh 3.50).

+ Di chuyn xung mt y b, dng lnh Replicate Radial cho kn y bng cch nhp cc tham s: paralell Z, number=35, angle=10, c kt qu (hnh 3.51).



184

+ V mt phn t nghing qua cc nt nh du, chia thnh 5 phn t, dng lnh Radial to thnh b, nhp cc tham s: paralell Z, number=35, angle=10) (hnh 3.52).

Hnh 3.50 Hnh 3.51 Hnh 3.52

V d 4 :

+ To h li Decac trong mt phng XZ, nhp cc gi tr : 3,2,4,40,5,5(m)

+ V 1 thanh thng theo phng X dng li th 2 (ti z=10m), chia thnh 10 on

+ V tr cu theo phng Z gia pha trn 1/3 ,chia thnh 3 on. V cc dy cp pha tri cu (hnh 3.53,3.54).

+ nh du cc dy cp va v, vo Edit Replicate Mirror chn Paralell Z, x1=20, y1=0; x2=20, y2=1 c mt na cu (ch h ta gc tri, pha di)

+ to ra 2 pha ca cu,chn All Mirror : Paralell X, y1=2.5, z1=0; y2=2.5, z2=1

+ V tip 2 dm 2 u cu.

Hnh 3.53 Hnh 3.54



185

V d 5 :

+ Gi th vin mu khung 1 tng 1 nhp File New Modal 3DFrame

+ Chn Open Frame Building, a vo cc tham s kch thc khung (1,4,1,6,6,15) nh hnh 3.55, xa bt cc thanh ngang ca khung, c kt qu nh hnh 3.56.

+ Gi th vin mu: Edit Add Temp Shell Multi-bay Cylindrical Shell vi cc tham s hnh 3.57: 15, 42, 4.5, 8,8,4 Locate origin : 3D,0,0,6,90 ,b restraint s c kt qu nh u bi.

Hnh 3.55 Hnh 3.56

Hnh 3.57

V d 6:

+ Gi khung phng mu (2DFrame)1 tng,1 nhp rng10m, cao 4m (hnh 3.58- h ta Global).

+ Chn h trc ta mi Define Coordinate System/ Grid Add System Cylindrical & a vo cc tham s : 2,36,1,6.5,10,3 (hnh 3.59 tri) ;

+ Vo Edit Grid Locate System (hnh 3.59 phi) Rotation in degree , about X=90 c kt qu nh hnh 3.60 h ta mi CSYS2 (cng gc ta vi

Global nhng h trc mi quay theo phng X so vi Global mt gc 90o ).



186

Hnh 3.58 Hnh 3.59 Hnh 3.60

+ Xa thanh ngang,v cc on thng ni gia khung v ng cong bng frame (ch v t cc u khung n cc im mt li). Chuyn v h ta Global, mt phng XZ s c kt qu nh trong u bi .

2.11.6. Khai bo vng cng

Khai bo vng cng ( Regid zone Offset) khi cc phn t dm , ct ( hoc cc thanh)

giao nhau ti mt nt c kch thc ln dn n s chng lp kch thc ( k n nhiu ln). Nu gi tr ny nh khng ng k, c th b qua nhng vi gi tr ln s lm cho kt

qu tnh khng chnh xc. Khai bo vng cng s khc phc c iu ny (chiu di tnh

ton gim). Ngoi ra kt qu ni lc s cho ti cc mp ca dm ( v tr nguy him tht s) ch khng phi ni giao nhau gia cc trc (nh trong trng hp thng thng).

khai bo vng cng: Chn Frame

Assign Frame End Offset s m hp thoi Frame End Offsets(hnh 3.61). Minh ha cho cc tham s v hiu ng vng cng trn hnh 3.62.Trong :

+ Total length : chiu di gia 2 trc thanh + Clear length : chiu di thng thy + ioff ( End I) : di vng cng ti u thanh I + joff ( End- J) : di vng cng ti u thanh J + Rigid-Zone Factor : H s vng cng

Hnh 3.61 Hnh 3.62



187

2.11.7. Rng buc chuyn v ( Constraint ):

Mt s thnh phn chuyn v ca nt c chuyn v bng nhau, ph thuc nhau ... c th

khai bo qua cc iu kin rng buc (Constraint), v d sn tuyt i cng ca kt cu nh cao tng, cc im ni trn mt cu .. . Khai bo rng buc dn ti gim s n s ca

phng trnh tnh ton, thi gian tnh ton cng nh phn nh ng tnh cht lm vic ca

cng trnh. c im khi khai bo Constraint:

- C th c nhiu nhm Constraint trong mt kt cu.

- Mt nt c th nm nhiu nhm Constraint.

- Khi tnh ton nh cao tng c sn tuyt i cng hoc li vch chu ti trng ngang thng gn Constraint.

Cch khai bo cho sn tuyt i cng (Diaphragm):

+ Chn cc nt trong tng mt phng sn

+ Vo Assign Joint Constraint s m hp thoi Assign/ Define Constraint, ti Choose Constraint Type to Add chn Diaphragm nhp v chn thuc tnh.

+ t tn ca Constraint : ty

+ Chn trc vung gc vi mt phng ang khai bo Constraint (thng l Z axis) OK.

2.11.8. Hiu ng un dc trong phn t thanh P-Delta :

i vi thanh c mnh ln, chu lc nn v un s xut hin hiu ng un dc P-Delta lm tng vng ca thanh , gy mt n nh cc b hay tng th (buckling). SAP cho

php t trc mt lc nn vo u phn t to ra chuyn v ban u ( khng phi ti

trng ngoi ) c khai bo trong P-Delta. c im:

- Ch tnh c ni lc do nh hng ca P-Delta ch khng tnh c ti trng ti hn Pth .

- C th xc nh lc nh hng P-Delta theo phng php trc tip (Assign Frame/Cable P-Delta Force )

- P-Delta ch tnh cho phn t thanh khi thit k cu kin BTCT (ct), kt cu thp v dy cp (Cable)

2.11.9. Thanh chu ng sut trc ( Prestress )

Trong mt s phin bn ca SAP, ng sut trc ch ng dng cho phn t thanh v do cc lc cng trc t ln mt hay nhiu si cp trong phn t (ti trng ny lun nm

trong mt phng 1-2 ca phn t ).



188

Cc d liu khai bo cho TT ng

sut trc (hnh 3.63):

+ Khai bo cc v tr t cp di, dj, dc

+ Khai bo lc ko t

+ Khai bo h s tnh ton

Hnh 3.63

Trong di , dj, dc l cc khong cch ca cc im neo tnh n trc thanh. tnh ti trng ng sut trc, phi qua hai bc :

- Bc 1 - Khai bo cc gi tr lin quan n lc cng T :

+ Chn Frame: vo Menu Assign Frame Prestress

+ a vo cc gi tr : End I =di=Start, End J=dj=End, Mid=dc=Center

+ Lc T= lc cng trc (Cable Tension )

+ OK

- Bc 2 : Khai bo h s tnh ng sut trc trong cc trng hp ti trng : nu ch khai bo cc tham s cho tnh ng sut trc phn trn m khng khai bo phn

ny, chng trnh khng k n cc lc ng sut trc .

+ Chn Frame

+ Menu Assign frame static load Prestress

+ Chn trng hp ti trng

+ Nhp h s ti trng tnh prestress.

+ OK

Ch : - C th c nhiu lc cng T khc nhau.

Ni lc trong mi trng hp ti trng do lc ng sut trc gy =Lc cng Tx H s ti trng tng ng.

2.11.10. Ti trng nhit

L do chnh lch nhit trong cc b phn kt cu, gy ra s bin dng nhit trong cc phn t e =a .Dl ( a : h s ; Dl : chnh lch nhit ).



189

2.11.11. Ti trng ph v ti trng theo thi gian

Trong cc chng trnh SAP, cc bi ton ng gm c: tnh ton kt cu do dao ng

ring, tnh kt cu chu dao ng cng bc, chu ti trng ng. Ti trng ng l cc ti trng c gi tr thay i theo thi gian, v d ti trng gi, sng bin, ti trng ng t, ti

trng ca cc xe di ng trn cu . . . Tt c cc ti trng ny u c th biu din di

dng phng trnh cn bng ng lc hc c N phng trnh vi phn bc hai :

M. (t) + C . (t) + K.U(t) = F (t) = S fj g(t)j

Trong :

+ M : ma trn khi lng

+ C : ma trn cn

+ K : ma trn cng

+ (t) , (t) , U(t) ,F(t) : tng ng l cc vc t gia tc, vn tc , chuyn v nt v vc t ti trng ngoi thay i theo thi gian. Tt c cc dng ti trng thay i

theo thi gian u c th biu din bi tng cc vc t khng gian f ( c lp vi

thi gian ) v hm thi gian g(t) .

tnh cho cc bi ton chu ti trng ng, trong SAP phi qua hai bc :

- nh ngha hm ti trng : khai bo dng v cc tham s ca hm qua chc nng Define (Bridge Load, Function. . .) (hnh 3.64).

- Khai bo s dng hm ti trng ng ( c) tnh kt cu: Define Analysis Case Add New Case hnh 3.66, Chn loi ti trng mun a vo kt cu trong Analysis Case Type : Response Spectrum, Time History, Moving Case. . . chng trnh s hin hp thoi tng ng cho ngi dng nhp cc thng tin cn thit (hnh

3.65).

Hnh 3.64 Hnh 3.65



190

Hnh 3.66

2.11.11.1. Ti trng ph v phn tch theo ph

Trong cc bi ton phn tch ng, tnh cho cc kt cu chu ti trng ng t, dng ti trng thng di dng ph gia tc nn . C mt vi thun li v tnh ton khi p dng

phng php ph phn ng phn tch ng t cho d bo chuyn v v ni lc ca h

kt cu. Phng php ny ch i hi tnh ton duy nht gi tr ln nht ca chuyn v v ni lc trong mi dao ng s dng ph thit k trn , m ph ny li l trung bnh ca

mt vi chn ng ng t .

Khi tnh ton, chng trnh SAP ch khai bo ti trng v tnh cho cc ti trng theo dng ph bit (ch khng c kh nng thit lp nn dng ti trng ph) theo cc chun ca

cc nc da trn s liu o c c th ca tng min, c kt qua nhiu nm. S gia

tng ca tc my tnh trong thi gian gn y cho php gii mt cch nhanh chng bi ton vi lng thi gian m phng ngy cng nhiu hn. Hn na gi y ngi ta c

th thc hin kim tra cho cc tnh ton thit k m trc y chng khng c thit

k vi gi tr nguy him nht tnh c bng phng php p ng ph .

Thng thng, cc ti trng ph ly t cc phng trnh cn bng ng kt hp vi phn

ng ca kt cu cng vi chuyn ng nn c dng :

Trong :

+ K - ma trn cng

+ C - ma trn cn i xng

+ M - ma trn cho khi lng

+ gx , gy, gz - gia tc nn phn b u

+ U, , - cc chuyn v,vn tc, gia tc tng i ca nn .

SAP2000 gii h phng trnh ny bng phng php chng mode (cng tc dng cc

dng dao ng ) do ph phn ng gy ra. Cc dng dao ng c th tnh theo phng

)t(um)t(um)t(um)t(UM)t(UC)t(KU gzzgyygxx &&&&&&&&& ++=++



191

php gi tr ring hay vc t ring. Gia tc nn theo mi hng c a vo nh mt ng cong ph s ho theo thi gian. Cc lc kch ng nn c th xut hin ng

thi theo ba hng, l hai hng bt k 1,2 vung gc vi nhau trong mt phng X-Y

v hng Z. Mc d cc gia tc c th khai bo theo ba hng, nhng ch c mt kt qu dng, n cho mi lng phn ng. Cc i lng phn ng c th l chuyn v, cc lc

v ng sut. Mi kt qu tnh ton biu th mt s o thng k ca bin ln nht c th

cho phn ng .Tuy nhin phn ng thc s bin thin trong khong t gi tr dng ny n gi tr m ca n.

Phn tch ph phn ng l tm kim phn ng ln nht c th c, n thch hp vi dng

phng trnh ni trn hn l hm thi gian. Mi trng hp phn tch gi l mt spec v c th t cho n mt tn. Mi spec c th khc nhau v cch p dng ph v t hp kt

qu.

Phn ng tng cng c tnh bng tng cc phn ng t ba hng bi cn bc hai ca phng php tng cc bnh phng (SRSS). Trong cc kt cu chu ph phn ng ng,

v tr Z dng phi l im hng ln.

c cc chuyn v ln nht v cc lc phn t (hoc ng sut),cc phn ng theo mt hng kch ng c th c tnh ton v sau c t hp theo phng php CQC

(Complete Quadratic Combination Technique).

Mi spec c mt h to ring khai bo cc hng ca ti trng gia tc nn (hnh 3.67). Cc trc ca h to ring ny k hiu 1, 2 v 3, theo mc nh n tng ng vi

cc trc X,Y,Z. H to ring mc nh c th thay i bng cch khai bo theo gc to

angle (mc nh bng 0).

Cc ph thit k l nhng ng cong thay i khng ng nht, t chng c dng nh l trung bnh cng ca nhiu ph ng t. thi im hin ti , nhiu tiu chun thit k nh ch nh ph thit k in hnh c dng l mt dy cc cp s gm gi tr thi gian ti cc im v gi tr gia tc ph theo 3 phng ca tng im .

- nh ngha hm ph, c th bng nhiu cch : ( R.S.Function Definition )

+ S dng mt hm c theo mc nh ca SAP ,v d cc hm UBC *

+ Gi ra mt hm ph c t trc v ct vo trong file vi tn mi : Add Function from file (khai bo Function name v Function file )

+ Khai bo mt hm ph mi : Add new fuction : a vo tn v cc tham s ca hm (thi gian v gia tc theo dng ph )

Khai bo cho chng trnh a hm ph vo tnh ton: Response Spectrum Case.



192

Tr

c gi

a t

c n

n

Trc thi gian t

Hnh 3.67 Hnh 3.68 Mt dng ca TT ph

V d mt hm ph gia tc nn trn hnh 3.68 v cch khai bo mt phn ca ph gia tc

nn theo phng X ( hnh 3.69) nh sau :

t S1 S2 S3

0.00

0.008

0.4

0.8

1.0

1.2

1.4

1.6

1.8

2.0

0.4

1.0

1.0

0.6667

0.5

0.4

0.3333

0.25

0.222

0.52

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Hnh 3.69

Gii thch mt s i lng trong qu trnh khai bo hm ph :

- Response Spectrum Function : Khai bo mt hm ph dng Add Function from file : nhp mt hm ph t mt file c. Trong :

+ Function name : t tn hm

+ Function file: khai bo ng dn m tp np vo s tnh

+ Function Definition : khai bo mt hm ph mi . Trong :



193

+ Function name : t tn hm

+ Function Definition : a vo cc gi tr ca hm nh thi gian t (time), gi tr ca gia tc S1,S2,S3 (value) tng ng cho tng im thi gian ca hm ph theo 3

trc, sau mi dng khai bo nhn phm add .

- Response Spectrum Case : khai bo cho mt trng hp ti trng ng tnh theo ph.

+ Spectrum Case Name : khai bo tn ca trng hp ph.

+ Excitation angle : gc kch ng.

+ Modal Combination : chn phng php t hp cc mode dao ng khi tnh ph.

+ Damping : h s cn.

+ Directional Combination : chn phng php t hp theo cc hng. Nu dng phng php GMC s khai bo thm tham s F1, F2 l cc tn s c trng cu

ASCE4 .

+ Input Response Spectrum : a vo tn cc hm ph s tnh theo mi hng v h s tng ng. C th ch tnh theo mt hng hoc c ba hng .

2.11.11.2. Phn tch theo hm thi gian

Ni chung ti trng tc ng ln kt cu l mt hm ty theo khng gian v thi gian.

Trong dng ma trn, n c th c vit nh R(s,t ). Vi tt c cc loi ti trng R(s,t), u

c th biu th bng tng hu hn ca mt dy cc vct ti trng khng gian Fi(s) v cc hm thi gian Ti(t) hoc di dng ma trn nh sau:

=i

iist tTsFR )()()(

Trong chng trnh SAP2000, cc vc t khng gian Fi(s) khai bo nh cc trng hp ti

trng tnh, hoc nh trong trng hp gia tc nn, nh mt hm ca ma trn khi lng. Cc hm Ti(t) c th l cc hm ty theo thi gian hoc cc hm c chu k nh cc

hm ti trng ca gi v sng bin. Chng trnh SAP2000 dng phng php chng

mode phn tch phn ng chun gii phng trnh cn bng ng hc chuyn ng ca ton kt cu.

SAP2000 thc hin tch phn chnh xc cc phng trnh cho mt bin phn tuyn tnh

ca hm thi gian Ti (t) gia cc im thi gian a vo. V vy cc kt qu l khng ph thuc vo vic chn khong thi gian tch phn nh mt vi phng php khc.

Cc i lng trong qu trnh khai bo hm thi gian :

Time History Function : Khai bo v m t hm thi gian (cho tng hm mt) bao gm :



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- Add new Function From file : a vo tn ( ung dn ) ca mt hm thi gian khai bo trc trong mt file no ( khng cn m t hm ) .

- Add new Function :m t mt hm thi gian mi, khai bo cc tham s nh hnh 3.70:

+ Function name : Tn hm

+ Period : chu k dao ng ca hm

+ Number of Step : s bc chia/chu k

+ Number of cycle : S chu k ( lp li)

+ Amplitude : bin

+ Time, Value : thi gian v gi tr tng ng vi cc t

+ Function graph: dng hm va m t

- Modify / Show Function : xem hoc bin i mt hm thi gian c

Delete Function : Xo hm khai bo.

Hnh 3.70 Hnh 3.71

Time History Cases : phn ny khai bo cc thng tin cn thit tnh ti trng ng c dng hm thi gian l ghp tng ng hm thi gian R(s,t) vi cc trng hp ti trng

tnh F(s), c hai loi ny u phi khai bo. Cc thng tin (hnh 3.71) bao gm :

- Time History Motion type : loi ti trng ng (c chu k hay khng c chu k) .

- Analysis Type : Kiu phn tch ( phn tch tnh,ng)

- Time History Type :Modal hay tch hp



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- Modal damping : h s cn (damping) , c th l hng s cho mi dng dao ng hoc khc nhau i vi tng mode .

- Number of output time step : S cc im cn a ra kt qu ( cn tnh )

- Out put Time step size : khong thi gian gia cc buc tnh .

- Load applied : a vo tn trng hp ti trng tnh gn tng ng vi hm thi gian.

2.11.12. Lin kt mm v tnh mng trn nn n hi

2.11.12.1. Lin kt n hi :

- Trong SAP2000 ch cung cp lin kt n hi bng cc lin kt l xo t ti cc nt. Di tc dng ca lc ngoi, l xo b bin dng v pht sinh cc thnh phn phn lc bao gm F1,F2,F3 , M1, M2,M3 ln lt l cc phn lc thng v phn lc xoay .

- Lin kt n hi dng trong cc trng hp nh dm lin tc c gi ta n hi , dm , tm trn nn n hi ( mng bng, mng bn ). chnh xc ca li gii t l thun vi mt ca li l x .

- Lin kt n hi - spring : l lin kt mm c th tc dng theo 6 thnh phn ca 6 bc t do, tuy nhin thng dng l theo phng Z.

- Cc thnh phn cng ca l xo c n v ( lc/n v di , lc /n v gc xoay).

- khai bo cng n hi vo Assign Joint Springs (hnh 3.72)

- gn cc cng n hi ( l xo ), trc ht phi tnh cc gi tr ca cng n hi. Trong

m hnh nn Winkler tnn coi nh n hi

tuyn tnh v c c trng bi mt h s nn . Trong trng hp n gin SAP2000 xut tnh

cngca mt gi l xo theo mt phng bt k

nh sau :

Ki= Ks .b.ls = Ks . A

Trong :

+ Ks h s nn

+ b,ls chiu rng v di m gi phi chu

Hnh 3.72

Bng gi tr h s nn mt s loi t thng dng :

- t ct xp : 4800-16000 ( kN / m3 )



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- t ct cht va : 9600 - 80000 ( kN / m3 )

- t ct cht : 6400 - 128000 ( kN / m3 )

2.11.12.2. Phng php xc nh h s nn :

Trong c hc t - nn mng nh bit , c rt nhiu m hnh nn c trng cho cc loi t nn khc nhau. M hnh nn do Winkler c s dng ngh hin nay ang c s

dng rng ri bi s n gin v thch hp vi mt s loi t thng dng ca n. Trong

m hnh ny , t nn c coi nhh n hi tuyn tnh, c trng bi mt h s nn.

- H s nn c xc nh bi cng thc sau:

Ks = As + Bs .Zn

Trong : As hng s ph thuc theo chiu su mng ; Bs h s ph thuc su ; Z su ang kho st ; n h s hiu chnh c gi tr gn vi ng cong thc nghim

(khng c kt qu th nghim th ly n=1 ).

2.11.12.3. M hnh tnh ton cc loi mng mm

i vi cc kt cu mng thng c hai phn : kt cu chu lc v phn nn. H chu lc c th m t bi cc loi phn t khc nhau nh dm ( mng bng ), tm ( mng b ).

Ngoi ra trong trng hp cn thit c th s dng phn t Plane , Solid . . .

M hnh ca mt s kt cu :

+ Mng bng - Dm - dng phn t thanh: gi l xo t ti cc im nt ca dm, mt tu .

V M V M Tng c : Dm

H H

Dm

t nn

Gi

L xo t nn Neo Neo

Hnh 3.73

+ Mng bng giao nhau - H dm giao nhau : gi l xo c th t ti cc giao im ca h dm hoc cc im bn trong.



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+ Mng b- Tm trn nn n hi : mng dng phn t tm, gi l xo ch t ti cc im nt ca phn t .

+ Cc chu lc ngang - Ch : Khai bo cc bc t do cho kt cu : UX , RY

2.12. V d: Tnh ni lc v chuyn v chn thp nc c vnh ai gia cng.

Hnh 3.74 S hnh hc

2.12.1. D liu

- Thp c 3 ct tit din bin i u, kch thc v tit din cho nh hnh v D1 (0.25 x 0.5); D2 (0.2 x 0.4),Lin kt :ngm ti cc chn ct

- Cc ct chia thnh 3 on ; cc vnh ai chia thnh 24 dm

- Vt liu b tng mc 300; E= 2.9E6T/m2, h s poisson = 0.18, w = 2.5 (T/m3); M = 0.25(T/m3);.

- Ti trng : khai bo 3 trng hp ti v 3 t hp ti trng

+ Trng hp 1 (TH1):Ti trng bn thn vi h s l 1.1 v ti trng phn b u theo phng Z tc dng ln cc vnh ai nh thp (z = 12). Vi vnh ai ngoi q1=1.4T/m; vnh ai trong v cc dm cho: q2= 1.8T/m.



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+ Trng hp 2 (TH2) : Ti trng gi theo phng X. Ti trng phn b theo phng ngang v tc dng ln tt c cc vnh ai nh + dm cho l q3= 0.3T/m.

+ Trng hp 3 (TH3): Lc tp trung ti 6 nt trn tr ti cc cao trnh z = 4 v Z =8 Vi P(z = 4) =0.5T , P(z = 8) = 0.8T

- Cc t hp ti:

+ COMB1 = 1x TH1+1 xTH2

+ COMB2 = 1 x TH1 + 0.9 ( TH2 + TH3)

+ COMB3 = Max Min ( COMB1, COMB2).

2.12.2. Hng dn cch lm : ( vi SAP2000V9.03)

- Chn New modalGrid only New Coord/ Grid system; (n v: T,m)nhp cc thng s:

+ Number of gridlines X direction: 3; Ydirection: 1; Z direction: 4.

+ Grid spacing: X direction: 0.75; Ydirection: 1; Z direction: 4.

2.12.2.1. Khai bo d liu: - Khai bo vt liu Define Material Add new material ( Nhp material name:

BTM300; module of elastic : 2.9 E06; Weight per unit volume: 2.5 ; Mass per unit

volume: 0.25; Poisson ratio: 0.18)

- Khai bo tit din: Trc ht khai bo cc tit din ch nht, sau khai bo tit din nonprimastic

+ Khai bo tit din ch nht : DefineFrame sectionsAdd RectangularAdd new property

Section Name Depth (t3) Width (t2) Material

S1

S2 S3 S4 D1 D2

0.6 (m)

0.533 (m) 0.466(m)

0.4(m) 0.5(m) 0.4(m)

0.25(m)

0.25(m) 0.25(m) 0.25(m) 0.25(m) 0.2(m)

BTM300

BTM300 BTM300 BTM300 BTM300 BTM300

+ Khai bo tit din khng lng tr ( nonprimastic): DefineFrame sectionsAdd NonprimasticAdd new property Hp thoai Nonprimastic Section definition nhp cc thng s nh hnh 3.74.a Bm Add .



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Hinh 3.74.a Hp thoi nh ngha TD nonprimastic

OK Khai bo xong tit din TD1 thay i t S1 n S2. Tng t vi TD2 (S2S3) v TD3(S3 S4).

- Khai bo cc trng hp tI trng (load case): Define Load Case Hp thoi Define Loads Nhp cc thng s nh hnh 3.74.b OK

Hinh 3.74.b

- Khai bo cc t hp tI trng: Define Combonations Define Response Combonation Add New Combo Response Combonation Data Khai bo d liu (Hnh 3.74b,c ng vi COMB2 v COMB3, COMB1 tng t COMB2)OK.

Hinh 3.74.c



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2.12.2.2. To s hnh hc

- V v chia phn t nh hnh.

- Gn tit din ( xem trong phn khai bo d liu)

- Bm hoc (Ctrl + A) chn tt c.

- EditReplcate (Ctrl + M) radial, thc hin t sinh theo

cung trn, quay quanh gc ta ( // trc Z, x= y =0).

Nhp cc d liu nh hnh 3.74.d

- Ln lut thm 3 HT tr cc cao trnh z = 4; 8; 12. Trnh t thc hin nh sau (v d z = 12, cn 3 ng li theo phng bn knh, 24 gc (25 ng li, mi gc bng

360o /24 =15o)

+ Define/ Coordinate system Grid/ Add new system/ Chn Cylindrical

+ Nhp cc thng s nh hnh 3.74.e

+ Chn Edit Grid (hnh 3.74.e) DefineGrid Data for system CSYSZ=12 chn Coordinate system chn 3D, nhp chuyn v thng theo

phng Z =12.OK (hnh 3.74.f)

- Ti gc di pha tri mn hnh chn HT va to

Hinh 3.74.d Hinh 3.74.e Hinh 3.74.f



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- ch 2 ca s (OptionsWindowsTwo titled vertical), mt 3D view, mt

trong mt phng .

- Trong mt rt v hai on dm vnh ai (hnh 3.74.g) v Replicate thnh 24 on (hnh 3.74.h)

Hinh 3.74.g Hinh 3.74.h

- SelectFrame sectionschn D2OK

- AssignAssign to GroupsAdd New GroupHp DefineAssign Group Name chn Group DefinitionTrong Group Name g DAINGOAIOK.

- Tng t vi ai trong v dm cho ta chn D1 v to thnh 1 nhm DAITRONG

- Tng t ti z =4 v z =8 ln lt thm cc HT tr v v cc dm ai nh u bi.

- Gn lin kt: Chn HT Globlal, trong mt phng xy, z=0 chn 3 nt chn

thpAssignJoints Restraint chn

2.12.2.3. Gn tI trng

TH1: (trng hp 1) + Menu SelectGroups

DAINGOAI OK + Assign Frame/Cable/Tendon

Loads Distributed Nhp cc d liu nh hnh 3.74.i OK

+ Select Groups DAINGOAI OK

+ Tng t trn, nhp 1.8 trong Uniform Load OK

Hinh 3.74.i



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TH2: (trng hp 2)

+ Trong mt phng xy, z = 12, dng ca s chn tt c cc phn t.

+ Assign Frame/Cable/Tendon Loads Distributed Nhp cc d liu nh hnh 3.74.j OK

TH3: (trng hp 3) + Trong ca s 3D chn 3 nt ti Z = 4

+ Menu Assign Joint Loads Forces Hp thoi Joint Forces.

+ Trong Joint Forces : ( Load case name: TH3; Nhp d liu nh hnh 3.74.k ->OK)

+ Tng t vi cc nt ti z =8.

Hinh 3.74.j Hinh 3.74.k

2.12.2.4. Phn tch v xem kt qu Analyze Set analyses options spaces frames OK Run .

2.12.3. Hng dn cch lm vi SAP2000V7.4

- Chn n v T,m

- Chn New modal Hp thoi Coordinate system definitionnhp cc th s:

+ Number of gridlines X direction: 4; Ydirection: 0; Z direction: 3.

+ Grid spacing: X direction: 0.75; Ydirection: mc nh;

+ Z direction: 4.



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2.12.3.1. Khai bo d liu

Nh mc 2.11.3.1.

2.12.3.2. To s hnh hc

- V v chia phn t nh hnh, gn tit din v chn ALL

- EditReplcate (Ctrl + M) radial trong rotate about chn trc z, number = 2, angle = 120.

- Ln lut thm 3 HT tr cc cao trnh z = 4; 8; 12. V d ti Z = 12

+ Menu OptionsSet Coordinate system Add systemCylindricalNhp cc thng s nh hnh 3.74.i Advanced Z = 12 ( hnh 3.74.m)OK

+ OK.

+ chuyn i gia cc h ta : OptionsSet Coordinate system Chn vo h ta mi OK.

- Cc bc cn li nh i vi SAP2000V9.03

Hinh 3.74.l Hinh 3.74.m

2.12.3.3. Gn ti trng Gn tI phn b u: Assign Frame static loads Point and uniform, tng t SAP2000V9., chn Load case v nhp lc vo Uniform.

Gn ti tp trung: nh SAP2000V9.



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Ch n v lc gc di pha phi mn hnh, trn khung nhp ti ca SAPV7.4 khng

c n v .

2.12.3.4. Phn tch v xem kt qu

3. Phn tch - Tnh ton

qu tnh phn tch chnh xc v t hiu qu cao, trnh gy li khi chy chng trnh,

ngi dng nn thc hin mt s thao tc trong bc phn tch :

- Kim tra m hnh kt cu

- La chn s tnh

- Khai bo cc tham s tnh ton v la chn phng n xut kt qu (c th kt hp trong bc phn tch hoc phn xut kt qu)

- Tnh ton Phn tch

3.1. Kim tra m hnh kt cu

y l mt bc khng bt buc nhng nn lm, nht l i vi cc bn sinh vin khi

thc hnh v lm bi kim tra, nhng ngi cha s dng thnh tho chng trnh. Trong phn ny bao gm :

3.1.1. Kim tra s hnh hc

a kt cu v cc mt phng XZ,XY,YZ, dng chut phi nhn vo mt s phn t trong

kt cu kim tra kch thc cc tng, cc nhp, mt s v tr c bit, nhng ni giao

nhau ca phn t, nhng ni xut hin nt ... cc thanh c chia nh, n v chiu di ng cha. Trn hnh 3.75, nhn chut phi vo phn t dm trn cng (m), mt s

thng tin v v tr, kch thc ... ca dm hin trn hnh 3.76

Hnh 3.75 Hnh 3.76



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3.1.2. Kim tra kch thc tit din

Trong phn ny ch :

- Kim tra khai bo , ng kch thc cc tit din c mt trong kt cu : Define Frame SectionModify/Show Property.

- Kim tra kt cu c gn ng tit din cha: View Set Display Option Frame Section. Nhng phn t no cha gn s c tn cc tit din mc nh ca SAP. V d, trn hnh 3.77 c phn t thanh dm tng 2, mu m cha gn tit din, s c

t gn tn l FSEC1.

- Kim tra s khng gian, dng khi (hnh 3.78 ): View Set Display Option Extrude view trnh nhng li do a vo cc kch thc khng hp l. V d, kch

thc mt thanh dm trn hnh 3.78 b sai v cha gn ng.

Hnh 3.77 Hnh 3.78

3.1.3. Kim tra tng trng hp ti gn

Nh bit, mi ti trng khi gn ch gn cho mt trng hp c th. Trong qu trnh gn,

ngi dng thng qun khng chn trng hp ti cho cc ti trng ang khai bo, do vy cc ti trng t ng nhp vo trng hp 1( Load1) v dn n sai khi tnh kt qu.

Trong phn ny, chng ta nn hin li cc ti trng ca tng trng hp (cho mi loi phn t) : Display Show Load Assign Chn Loi i tng (Joint, Frame, Shell ...).

Ch ; khi s dng Frame, cc ti trng ti nt cng trong trng hp ti cng hin. Trn

hnh 3.79, 3.80 hin cc ti trng gn cho trng hp 1 (TH1) v TH2 ngi dng

kim tra.



206

Hnh 3.79 Hnh 3.80

Ngoi cc bc kim tra trn, ngi dng c th kim tra thm cc thng s v vt liu,

cc h s t hp, lin kt . . .

3.2. La Chn s tnh : Analyse Set Analyse Option

Theo mc nh, SAP2000 cho php c 6 bc t do ca cc nt trong kt cu chuyn v c, iu ny ch ph hp vi kt cu Space Frame v Shell. Trong trng hp m hnh

tnh ton l cc dng kt cu khc, ngi s dng phi chn v khai bo cho chng trnh

qua 2 cch :

- Vi mt s kt cu nm trong bng kt cu mu ca SAP trong Fast DOFs trn hnh 3.81 th ch cn nhn vo biu tng, SAP t ng gn cc tham s ca Degree of

fredom v nhn dng kt cu

- Vi cc loi kt cu khng c trong cc kt cu mu ca SAP th ngi dng phi khai bo cc bc t do cho cc nt ca ton kt cu trong cc tham s ca Available

DOFs.

Hnh 3.81



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Cch khai bo Available DOFs cho mt s loi kt cu khng nm trong bng mu ca SAP :

+ Dn phng : ch chuyn v theo Ux v Uz

+ Dn khng gian : ch chuyn v theo Ux, Uy v Uz

+ Tm phng : Uz , Rx, Ry

+ Phn t ASOLID: Ux v Uz ;

+ Phn t SOLID : Ux , Uy v Uz

3.3. Thc hin tnh ton : Analyse Set Analysis Case to Run

thc hin tnh ton (phn tch kt cu) vo Analyse Set Analysis Case to Runs la chn cc trng hp ( khai bo) cn tnh v trng thi Run trong Action sau

nhn Run now.

Hnh 3.82 Hnh 3.83

Chng trnh SAP2000 c th phn tch tnh v phn tch ng cc s kt cu, cho c

cc bi ton tuyn tnh v phi tuyn. Sau y s trnh by qua cc loi phn tch m SAP c th thc hin c v mt s thng tin c bn cho cc loi phn tch ny.

3.3.1. Cc loi phn tch : - Phn tch tnh : ch chu cc ti trng tnh, khai bo Linear Static. y l loi phn tch

thng thng m bi ton no cng thc hin. Ngi s dng ch cn chn cc trng hp, t hp cn tnh v t Action l Run( hnh 3.83).

- Tnh dao ng ring : khai bo Modal (Mode shape). Trong mt s phin bn u ca SAP2000 (v d V7.4), khi mun tnh dao ng ring cho kt cu, ngi s dng cn kim tra chnh xc gi tr ca M (khi lng ring) trong phn khai bo vt liu,

khai bo s dng dao ng (Number of Mode) v chn phng php tnh trong phn Analysis OptionSet Dynamic Parameters (hnh 3.82). Trong cc phin bn gn y, SAP2000 t gn thm mt trng hp MODAL vi s cc dng dao ng mc



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nh l 12 trong Set Analysis Case to Run (hnh 3.83). Ngi s dng mun tnh dao

ng ring ch cn chn Action l Run, v b qua tnh dao ng ring nu chn Not Run.

- Phn tch P-Delta: bi ton n nh ( chn P-Delta)

- Phn tch ng :Vi cc loi phn tch ng, ngi s dng phi khai bo cc hm ti trng ng trong phn Define Function, gn cc hm ti trng cho nt, phn t trong kt cu nh mt trng hp ti c lp. SAP2000 s tnh v cho kt qu ca ti

trng ng qua cc trng hp ny. C th lit k mt s loi ti trng ng m SAP2000 c th phn tch c nh sau:

+ Ti trng iu ho ( Harmonic steady-state ): v d ti trng do cc my mc t trong cng trnh khi lm vic sinh ra.

+ Phn tch ph phn ng ( Response spectrum ) :Ti trng c gia tc nn, v d ng t.

+ Phn tch theo hm thi gian ( Time History) : c th cho bi ton tuyn tnh, phi tuyn. V d ti trng sng bin, gi...

- Phn tch vi ti trng di ng : bi ton cu (Bridge Load).

Cc kiu phn

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