Danh gia anh hu'O'ng cua do cCpng dat nen doi vai cong trinh nha cao tang du'O'i tac dung cua dong dat
Ngay nhan bai: 30/7/2014 Ngay siTa bai; 15/8/2014 Ngay chap nhan dang: 10/9/2014
T 6 M TAT:C6ng trinh nha cao tang phan Ung rat nhay vcri sU rung chuyen cua dat nen. Khi cdng trinh chiu tai trpng dong dat, tUcfng tac giUa dat nen va ket cau {SSI - soil-structure interaction) CO anh hUdng dang M den dac tinh dao ddng va phan ilng dgng cua he ket cau. IVIuc dich chinh cua bai bao la phan tich iing xii cua ket cau trong mo hinh tinh toan cd xet den SSI. Tai trpng d^ng dat theo phucjng ngang dupc xet den theo phdong phap phan tich lUOc sU thdi gian. Viec m6 phong mong dpn trong khong gian 2D sii dung mo hinh dam tren nen phi tuyen Winlder (BNWF - Beam-on-Nonhnear-Winkler-Foundation). So vcri cac phan mem thong thudng khac, phan mem ma i ^ o n md OPENSEES (Open System For Earthquake Engineering Simulation) da dang hOn ve loai vat lieu va loai phan tii nen no co the giai quyet duoc bai toan SSI mot each hi^u qua. Chu ki dao dpng co ban, chuyen vi dinh cua cong trinh va npi liic ciia cot la nhfing yeu to thay doi dang ke va can dUOc xem xet cu the trong qua trinh phan dch.
TU khoa: tUcfng tac giiia dat nen va ket cau, phan Lfng dpng ciia hien tilpng dpng dat, chan cong trinh linh hoat, phan tich theo liipc sii thtri gian
ABSTRACT
BuOdings are vulnerable to shaking of soil. During seismic excitation, soil-structure interaction (SSI) effects a considerable change of vibration characteristics and dynamic responses of structure system. This paper's goal is to analyse the behaviors of structure in SSI model. Lateral seismic load is applied to model in time history analysis. The 2-dimensional conception of shallow foundation is based on Beam-on-Nonlinear- Winkler-Foundation (BNWF) model. Compared with other programs, OPENSEES (Open System For Earthquake Engineering Simulation) is more diverse in material and element types; therefore, it can solve the SSI problem effectively Vibration period, top displacement and force of column are significantly changeable, all of which need inspecting in process of studying.
Key words: soil-structure interaction, seismic response, flexible bases, time history analysis
Chu Quoc Ihang
Trudng Dai Hpe Quoc Te, Dgi Hpe Quoc Gia TP. H6 Chi Minh TrSn Dang Khai
TriJcJng Dai Hoc Bach Khoa, D^i Hoc Qu6c Gia TP. Ho Chi Minh V u X u a n P >
Tran Cao ^ 1 - - h N g o c
Tnf6ng V ^^°^ '^' ^ ^ Hpe Quoc Gia TP. Ho Chi Minh
Chu Quoc Thing, Tran Dang Khai, Vu Xuan Bach,
Tran Cao Thanh Ngoc
I.Mdrdju
Bai toan tUong tkc giu'a dat nen va ket cku dang duoc quan tam ntiieu trong nhCrng nam gan day iDdi tinh ctilnh xkc vk hap \y khi duoe dUa vao m6 tilnh phan tich. N6 mo phdng dUoc he lam viee dong thdi eua ket cku vk dat nen trong qua trinii chiu t^i trong dong dat.
Viee tinfi to^n eong trinh chiu dong dat thu6ng dua tren gi^ d|nh rSng nen mdng nhU mot khoi cUng va chiu tokn bo gia tdc ngang mot chieu. Gia d|nh nky eo gia trj neu he ket cau duoe dat tren nen dat tot vi khi do ehuyin vi 6 chan cong trinh giong vdi trUctng chuyen vj eua dong dat. Tuy nhien, khi dat nen la yeu thi se CO sU khae biet dang ke. Do nhUng 5nh hudng nhutren thi viee ke den vai trd eua dSt nen trong md hinh SSI khi phan tieh cong trinh chju ddng dat la dieu can thiet.
Vardanega [2], Stewart va eac cdng sU [3], Ahmed va Hamdy [6] da cd nhCing nghien cUu ve anh hudng cua SSI den Ung xil eua ket cau.
Tuy nhien, [2] cd phuong phap tinh va md hinh don gian, [3] chl nghien eiJu ki ve ehu ki dao ddng va [6] chUa danh gi^ dUoc knh hudng eua do eUng dat nen la nhU the nao. Bai bao sUdung phan mem OPENSEES vi day la phan mem ehuyen dung de phkn tieh eac cong trinh ch\u tai trpng ddng dat va duoc ti'ch hop sin nhi^u loai vat lieu ehuyen cho viee md phdng bai toan SSI. Vdi nhu'ng loi thi do, bai bao se dua ra nhiing md hinh hop ly va sat vdi dieu kien lam viee thuc ti cua eong trinh. Khi xet den vai trd cua SSI va khi thay doi do cUng cua dat nen, sU thay ddi ket quS eUa cac thdng sd dau ra deu dUOe xem xet cu the va rd rang.
2. Mo t^ mo hinh
De danh gia anh hudng do tUOng tac giCfa dat nen vk ket cau khi cdng trinh chju tk\ trong dong dat, bai bao da tien hanh phan tich va tinh toan 3 m6hinh:4 tang, Stang va 12 tang.
Qua trinh phan tich cd xet SSI va khdng xet SSI lan lupt dUdc thUe hien vdi moi md hinh. Ooi vdi mo hinh cd x^t anh h u ^ g cua SSI (md hinh SSI) thi vai trd cua do cUng dat nen kha quan trong Do do, 3 loai dat nen (loai 1, loai 2, loai 3 theo thU tu cd do CLlng tang d5n) lan luot dupc
I f
Bang 1. Kich thudc cija cac c Cau kien C d t - 4 T a n g D a m - 4 Tang Cdt-8&12Tang Dam-8&12Tang Mong Cot Gdc Cl - 4 Tang Mdng Cdt GiUa C 2 - 4 T a n g
Mdng Cdt Goc Cl - 8Tang M d n g C d t G i u ' a C 2 - 8 T a n g Mdng Cdt Goc Cl - 1 2 Tang Mdng Cdt Giu'a C2 - 12Tang
u kien be t d n g cdt thep Kich thude (em)
50x50 20x60 65x65 25x70 120x120x100 200x200x100 160x160x120 250x250x120 220x220x150 320x320x150
Cot thep 16(|)20 Tren 2^20, Dudi 3(|i20
16(1.22 Tren 2<|i22, DUdi 3iti22 O u o c m d phdng bSng phan t i i d a m dan hdi
-nt- -nt- -nt- -nt- -nt-
Ghi chu
<|)25 doi vdi m o hinh 12 t^ng
<ti25 ddi vd^ m d hinh 12 tang Chieu sau chdn m d n g : 150 cm
-nt- Chleu sau chdn mdng. 160 cm
-nt- Chieu sau chdn m d n g 200 cm
-nt-
IMPERIAL VALLEY
r%^.
lh 1 Bleu So ga toe n^n: (a) Chalfant Valley, (b) Imperial Valley, (c) Coalmga, (dj Loma Pneta
f 1 I
i»snnn^i5Di)i) J.
u w
IxSCUO-lSUOO.Hinh 2. (a) M6 hinh 8 tang {lihong Ket SSI) (b) Mo hinh 8 tang (to xet SSI)
sis dung trong md hinh SSI de danh gia knh hudng eua dd cUng 3at nen den ket qua bai toan.
— I Cac md hinh se chiu tai trong ddng dat theo p h u o n g ngang tC/
I 4 tran ddng dat: Chalfant Valley, - - imperial Valley, Coalmga, Loma Pneta ed bien do gia toe nen lan lupt la 0.21g, 0.25g, 0.28g, 0.28g.
_ Cac mo hinh duoc m o t^ la khung ph5ng cd 3 nhip (moi nhip I 5m), mdi tang cao 3,5m. Ddi vdi I .^ m o hinh 4 tang: eac cdt co kich M ^ thudc 1^ 50x50 cm, cac dam cd I kich thudc la 20x60 cm. Ddi vdi
" ^ md hinh 8 tang, 12 tang: cac cdt cd kich thude la 65x65 em, cac
dam cd kich thudc la 25x70 cm. Cac thdng s6 ehinh cCia m d h i n h duoc eho trong bang 1;
Loai vat lieu be tdng dupe sU dung trong mo hinh la C o n c r e t e d . Day la loai vkt li^u b&
t d n g ddn true theo Kent-Scott-Park va khdng xet den kha nang chiu keo. Loai vat lieu th^p dupc SLT d u n g trong m o hinh la SteelOl. Ojiy la loai vat lieu t h e p d o n true song tuyen tinh.
Tiet dien mat cat ngang cCia cdt dUoe chia lam 2 phan: co nen ngang va khong cd nen ngang.
Moi phan dupe khai bao gia tri cudng do khkc nhau. Nhd d d , anh hudng eCia hien tUOng be t d n g bi nen ngang cd t h ^ dUOe xem xet trong c^c m d hinh. Day la Uu diem cOa OPENSEES so vdi cac phan m e m t h o n g thudng khac.
Trong d d : epscO: bien dang eua be tdng 6 cUdng do Idn nhat. fpe: eUdng do nen cua be t d n g d 28 ngay. epsu: bien dang cda b& tdng d cudng do nen v d be t d n g . fpcu: cUdng dp nen v d be t d n g . Fy: cudng d p ehay deo cda thep. EO;
md dun dan hdi ban dau cua thep. b: t;/ sd giila md d u n ehay deo lue sau va m d dun dan hoi b a n d ^ u c C i a t h ^ p .
3. M o hinh ti/tfng tic giiira dat n l n Vct k£t cSu
Phan tU "forceBeamColumn" tif t h u vien OPENSEES duoc d u n g de khai bao ket ciiu ben tren (dam, cdt). Viec m d phdng mdng don t r o n g khdng gian 2D silr dung phan tCf
"elasticBeamColumn". Phan tCr "zeroLength Element" dUdc dung de md ta Id xo tuong tcic giCra dat nen va ket cau. Lo xo theo phuong dUng dupe gan vat lieu QzSimple2. Dp cUng cOa Id xo theo p h u o n g ngang bkng kha nang chdng trUcft theo p h u o n g ngang do ma sat giu'a day m d n g va dat nen cdng vdi kha nang chiu ^p lUc bj ddng cua dat nen. Nhu vky viec md hinh ddi hdi phai cd 2 Id xo theo p h u a n g ngang tai cdng 1 Vj t r i va ph^i d^m bSo 2 Id xo nay hoat dpng dde lap vdi nhau. C^e phan m^m t h u d n g khdng the md phdng dupe van de nay. Tuy nhien, nd ed the duoc thUe hien vdi su hd t r o cda p h ^ n mem
1081
^ ' ^ " ' ^ ^ " P Phan belong
(a) (b) (t) Hinh 3. (a) Quan he ifng suat-bien dang 3ae tnitig cCia vSt lieu ConcreteOl, (b) Quan he iJng suat-bien dang dac trimg ciia vat lieu SteelO! Miong xet den sirtang ben dang hiMng, (c) Phan be tong trong cot co xel den nen ngang [4]
Hinh 4. M6 hinh tmmci tac giiia dat nen va Itet cau [5]
Biing 2. C h u k i d a o d d n g cua m d h i n h M O H l N H
4 T 3 n g 8 T a n g 12 TSng
T(s) FB 0.78 1.18 1.63
t(s) SSM 1.29 2.34 2.92
SSI2 1,07 1.55 2.02
SSI3 0.95 1.38 1.83
t/T SSIl 1.66 1.98 1.80
SSI2 1.38 1.31 1.24
SSI3 1.22 1.17 1.12 BSng 3. Kfch thudc cua cac ket cau ben tren sau khi dupe tang len lan thU 1
Cau kien C d t - 4 TSng D a m - 4 Tang Cdt-8&12Tang Dam -8& 12 T 3n g
Kich thude (em) 60x60 25x65 70x70 25x75
Cdt thep 16i}i22 Tren 2iti22, Dudi 3iti22
16<ti25 Tren 2*25, DUdi 3it)25
Ghi chu
4i28 ddi vdi md hi nh 12 ^ n g iti28 ddi vdi m d hi nh 12 6ng
BSng 4. Kich thUde eiia cac k^t cau ben tren sau khi dUdc tang len lan thU 2 Cau kien
C d t - 4 T a n g D S m - - ! - - g C d t - 8 & J Dam - "••'9
Kich thudc (cm) 70x70 30x70 80x80 30x80
Cdt t h e p 16*25 Tr&n 2<ti25, Dudi 34)25
16*28 Tren 2*28, DUdi 3*28
Ghi chii
* 3 2 ddi vdi m d hinh 12 tang
* 3 2 ddi vdi md hi nh 12 ^ n g
OPENSEES 2 Id xo theo phUOng ngang lan lUOt duoc gkn vat lif u PvSimple2 va TzSimple2. Vdi cac vat lieu QzSimple2, PySimple2 va TzSimple2 thi phan Ung eua Id xo theo ck 2 phuong la phi tuygn va khdng dan hdi. Nhd dd, eac m d hinh se phiin anh dUOc bkn ehat lam viee ddng thdi giCa ket cau va dat nen mpt each hpp ly.
Kha nang ehju lUc cue han ciia Id xo QzSimple2 theo phudng ddng dUdc tinh theo cdng thdc eUa Meyerhof [5]:
q^ =i:N^F^F +^D,N,F/_F^+0.5-/aNF^F_F (1) Trong dd: c: lUc dinh eua dat. y: trpng luong neng cua dat. D,: ehieu sau chdn mong. B- be rdng cda mdng. N^N ,N • he sd khk nang chm lUe. F^^,F^j,F^ he so kha nang chiu luc theo hinh dang. F^j.F^F^: he sd kha nang chiu lUc theo d p sau. Fj^,Fj||,F.^: he sd khci nang chiu lUe theo dp nghieng.
KhS nang chiu lUc cUc han cda Id xo PySimple2 theo phuong ngang dUpc t i n h tr^n kha nang chju ap lUc bi ddng cua d^t [5]:
p_^=o,SrK^D; (2) Trong do: y. trpng luong rieng eiia dat. K .
he so ap lUe dat b| ddng dupe tinh dUa theo Coulomb [5]. D,: chieu sau chdn mdng.
Khk nang chiu luc cUc han cua Id xo TzSimple2 theo phUOng ngang dUdc t i n h b5ng tdng kh^ nang ehdng tf uot theo phuong ngang [51:
Trong dd: W^: trong lupng ciia ket cau ben tren teic dung len mdng. (p: gdc ma sat giUa mdng va dat (thudng bang l/3it) den 2/3<t>). iJi.
gdc ma sat cua 3kt. A^: dien tieh mat day ciia mdng tiep xuc vdi dat. c:IUc dinh.
Op cUng theo phUOng dUng (KJ va phuong ngang (K^) ciia mdng dUoc tfnh theo goi y trong ATC-40 cua Gazetas [5] danh cho mdng ndng.
4. Ket qua dat dU0c tif md hinh va nhan xet Mdt sd ki hieu dUoc sir dung trong phan trinh bay ket qua:
• Md hinh khdng xet den SSI (FB - fixed base)
• Md hinh cd xet den SSI va dUOc dat tren dat nen loai 1 (SSIl - soi I-structure interaction, soil type 11
• Mo hinh cd xet den SSI va dUOc dat tren dat nen loai 2 (SSI2 - soil-structure Interaction, soil type 2)
• Md hinh cd x^t den SSI va duoc dat tren dat nen loai 3 (SSB - soil-structure interaction, soil type 3)
• Chu ki dao ddng ciia md hinh khdng xet den SSI (T)
• Chu ki dao ddng cua m d hinh cd xet den SSI ( t )
• J'^ so ehu ki dao ddng (T/T) Oat nen loai 1, loai 2, loai 3 theo t h U t u e d dp Cling tang dan
4 . 1 . Chu ki dao dong ciia mo hinh Ddi vdi ca 4 tran ddng dat (Chalfant Valley, Impenal Valley, Coalinga, Loma Prieta) thi chu ki
Sang 5. Chu ki dao ddng eiia m d hinh khi do cUng K ciia ket cau ben tren dUOC tang len lan thU 1
M O HlNH
4 Tang 8T^ng 12Tang
T{s) FB 0 60 1.01 1.46
t { s )
ssn
1.13 2.21 2.81
SSI2 0.93 1.40 1.88
SSB 0.80 1.22 1.68
t/T ssn
1 87 2.19 1.92
SSI2 1.54 1.39 1.29
SSB 1.33 1.21 1.15
Being 6. Chu ki dao ddng ciia md hinh khi do cUng K cua ket cau ben tren duoc tang len lan thU 2 M O HlNH
4 Tang 8 Tang 12Tang
T{s) FB 0.47 0.83 1.20
t(s) ssn
1.00 2.11 2.65
SS12 0.81 1.24 1.67
SSB 0.68 1.07 1 46
t/T
SSIl 2.13 2.55 2.21
SS12 1.72 1.50 1.40
SSB 1.44 1.29 1.22
"^^::;z
— oinKunayiriiiK - - tang K lin 2
U_ -.- j
Hinh 5. Ty so diu ki dao dong : (a) Mo hinh 4 tang, (b) Mo hinh S tang
^^fw. —
35 4 -01
0 -"=1 Disp
• #
XNoaea
\m
-12stones SSIl
W" -
20 25 30 35 4
le 49 - 12SIone$ SSI 3
}m"'- I ° '"11 I IV''^" "*J-^^
Hinh 6. Chuyen vi flinh cua mo hinh 12 tang theo phuong ngang (m) - Imperial Valley (a) FB, (b) SSIl, (c) SSI2, (d) SSI3 dao ddng cua cac m d hinh deu gidng nhau va ddng ciia he ket cau se tang len dang ke {cd ket qua dupc trinh bay trong bang 2; trudng hpp tang den 98%). Khi d d cdng cda dat Nhan xet: Khi xet tuong tae giira da't nen nen tang len thi chu ki dao d d n g gikm xudng va ket cau vao md hinh tinh toan thi chu ki dao va t y so chu ki dao ddng t / r eung g\km xudng.
Nhu vay, ehu ki dao d d n g va t J sd chu ki dao d o n g T/T deu t y IS nghjeh vdi d p cijfng dat n^n.
Tiet dien dSm vk edt eiia eac md hinh se duoe tang len, cac t h d n g sd khac deu dUpc giiJ nguyen nhkm phan tieh sU thay doi ket qua ty so ehu ki dao d d n g T/T khi dd cUng cda ket cau ben tren tang len Viee phan tich nay kha quan trpng vi t ^ sd ehu ki dao ddng T/T phJin anh dp gia tang nhieu hay it ciia chu ki dao ddng n^u x^t den SSI
Nhan xet: Hinh 5 cho thciy f) sd chu ki dao ddng t>J le v6i do eUng eua ket eau ben tr^n va ty le nghieh vdi d p cu'ng ciia d i t n^n. NhUvSy, t y sd chu ki dao d d n g t^ le vdi t^ sd d p ciSng cua ket eau ben tren/dat n^n. Md hinh cd d p eUng k^t cau ben tren Idn dUpc dat tren dat nen ed d p c i ^ g khdng cao thi chu ki dao ddng se tang kha Idn (cd t r u d n g h p p tang den 155%) neu xet den anh hUcmg eua SSI.
4.2. C h u y e n v j t f i n h cCia m o h i n h Nhan xet. Chuyen vj dinh theo phUdng ngang ciia cac m d hinh khi chiu tac dung eiia 2 tran ddng dat Chalfant Valley, Imperial Valley thay a6\ theo quy lu^t t u o n g ddi rd r i n g . Khi xet den anh hUdng do tUOng tac giUa dat nen va ket eau thi chuydn vi dinh theo p h u o n g ngang tang ten dang ke (ed trUdng h p p tang den 56%). Khi dp cUng cda dat nen tang len thi chuyen vj dinh giam xudng. Ddi vdi 2 tran ddng dat Coalinga, Loma Prieta t h i quy luat bien doi nay khdng con rd rang nUa. NhUng t r o n g da so cac trUdng hpp, SSI deu lam tang chuyen vj dinh. Nhin chung, chuyen vj d i n h ciia m d hinh se tang len khi xet den SSI.
4 . 3 . N o i lire I d n n h a t cda cot Cdt gdc (biing 8)
M o m e n t Idn nhat chan cot (Mmax): Mmax g i l m xudng dang k^ (cd trUdng hpp g\km den 70%) Khi d d cUng dat nen tang len: Mmax c6 xu h u d n g g\km xudng ddi vdi md hinh 4 tang;
Mmax cd xu h u d n g tang len doi vdi md hinh 12 t a n g ; Mmax co lOc tang, cd luc gl^m ddi vdi md hinh 8 t a n g . N h u vay, do cCfng dat nen anh hudng n h u the nao den Mmax phu thudc vao 2 yeu t o ia chieu cao md hinh va tran dpng dat tac d u n g vao m d hinh. M o t kh^ng d m h rd rang la khi xet den SSI thi Mmax giam xudng kha nhi^u {til 30% den 70%) trong tat ck CBK. trUdng hop.
Luc cat Idn nhat chan edt (Qniax): Qmax giam xudng dang ke ( t i l 20% den 65%) trong hau het tkt ck cae trUdng hop dupe xem xet. Khi d d cUng dkt nen tang ien thi Qmax ciing tang l^n. N h u vky. Qmax f^ I f vdi d d cijfng ciia dk nen.
Luc doc Idn nhat chSn cdt (Nmax): ddi vdi m d hinh SSIl, Nmax gl5m xudng tir 12% den 42%. Khi d p cijmg dSt nen tang lin (md hinh SSB) thi Nmax tang len vk tang den gan b§ng Nmax cua md hinh FB.
Cot giu'a (bSng 11)
Moment Idn nhat chan cdt (Mmax): d d i vdi m d hinh SSn, Mmax g i i m xudng tU 10% den
ilOjBWEI'EIiQl 09.2014
B i n g 7. Chuyen CHALFANT VALLEY
4 Tang STang 12 Tang COAUNGA
4 Tang ST^ng 12Tlng
vi dinh Idn n h i t theo phUong ngang ciia cac m d FB
0.039 0.04S 0.0S9 FB 0.173 0.217 0.2O9
ssn 0.043 0.067 0.078 ssn 0177 0 196 0.244
SSI2 0 043 0.0S8 0.078 SSI2 0.209 0.227 0.223
5513 0.040 0053 0075 SSI3 0.188 0,233 0,220
IMPERIAL VALLEY 4 Tang STang 12Tang LOIMA PRIETA
4 Tang 8 Tang 12Tang
hinh (m) FB 0 0 6 4 0 1 0 2 0 1 6 0 FB 0 0 7 5 0 . 1 1 4 0 152
S S I l 0 1 0 0 0 155 0 2 3 9
S S i l 0,103 0,122 0,152
5512 0 0 9 1 0 1 4 0 0.221 SS12 0 1 1 6 0 1 3 4 0 1 5 0
SS13 0,083 0.123 0,190 SSI3 0,110 0 . 1 1 9 0.149
Bang 8. Moment Idn nhat chan cdt gdc (kN.m) Moment max
CHALFANT VALLEY 4 tang 8 tang 12 tang Moment max
COALINGA 4 tang Stang 12 tang
Cot goc FB 197.6 351-3 608.3
SSIl 5069 250.9 222,7
SS12 9 0 , 4 242-9 3 0 4 . 1
SSB 8 8 , 4 196,8 3 6 8 . 0 Cot goc FB 540.7 988.8 880.8
5SI1 2585 294 8 288,2
SS12 2 2 0 . 6 2 7 4 . 4 3 3 6 . 7
SSI3 2 6 8 1 4 4 2 . 8 4 8 2 . 2
M o m e n t m a x IMPERIAL
VALLEY 4 t a n g 8 t a n g 12 t a n g M o m e n t m a x L O M A PRIETA 4 t a n g 8 t a n g 12 t a n g
C o t g o c FB 3 4 2 8 7 4 6 7 8 1 6 . 4
SSIl 181.5 247.4 322.8
SSi2 1470 257 6 3018
SSI3 148-8 297.1 S22.3 C o t g o c FB 396!
730,8 832.3
ssn 233.3 218.5 321.8
SS12 2 1 0 . 4 2 6 8 4 3 5 4 1
SSB 205,7 253.4 4 4 2 4
BSng 9. LUc e l t Idn nhat chan edt gdc (kN) Li/ccStmax
CHALFANT VALLEY 4 tang Btang 12 tSng LUc c3t max COALINGA
4 tang Btang 12 tang
Cot goc FB 68.5 110.8 222 3
ssn 35.2 112.7 123.5
SSI2 44.6 13S.7 144.3
SSI3 53,6 115,0 166.0 Cot goc FB 196.5 276-9 257.5
SSIl 864 98 6 133 6
SSI2 107.1 117.8 1664
SSB 141.2 139.8 184.2
LUc cat max IMPERIAL
VALLEY 4 tang 8t^ng 12 tang Luc tat max LOMA PRIETA 4 lang 8 tang 12 tang
Cotgoc FB 139-1 255-1 264 9
SSIl 60,8 86.9 109,4
SSI2 70,5 1101 1442
SSI3 817 136.5 189.4 Cot goc FB 160-9 228,0 274-7
5SI1 78,3 99.0 161,3
5512 100.0 137,5 1906
SSB 121.7 141.5 210.4
Bkng 10. Luc doc Idn nhat chan cdt gdc (kN) Luc doc max
CHALFANT
Btang 12tSng
COALINGA 4 tang Stang 12 tar.
Cot goc FB 470.9 995 6 1568 9
T
FB 294
81.8
!5 7 SSIl 417.5 845.1 1362.4
5SI2 441.6 965 1 15S5 7 cat goc SSIl 474.6 863.4 18213
SS12 6 1 3 6 1 3 9 7 9 2 2 6 3 . 9
SSI3 4 5 4 4 9 9 4 6 1 6 1 9 6
5513 6 4 7 . 6 1501.5 2 4 4 0 . 4
IMPERIAL VALLEY 4 t a n g S t a n g 12 t a n g
LUc d o c m a x L O M A PRIETA 4 t a n g S t a n g 12 t a n g
C o t g o c FB 522,2 1 3 2 3 0 2 3 6 8 . 2
ssn
4 5 8 , 5 854-7 1574.1
SSI2 535.6 1 2 6 9 3 2 1 6 8 0
C o t g o c FB 555.5 1316,2 2 3 1 6 , 5
SSIl 4 7 2 , 2 8 5 9 2 1606 1
SSI2 5 7 5 3 1262,1 1 9 4 6 3
SSB 534.1 1 3 2 6 5 2309.5
5513 580.9 1333.4 2 1 0 1 . 0
50%. Khi dd cifng dat nen tang len {md hinh SSB), Mmax tang len va tang den gan bang Mmax eiia md hinh FB. Dac biet, cd trudng h t ^ Mmax tang vUpt 20% Mmax eiia m d hinh FB.
N h u vay, neu cdng trinh dupe dat tren dat nen cd do cdng cao thi Mmax cd khk nang se tang len khi xet den anh hudng cua SSL
Lye eat Idn nhat chan cdt (Qmax): ddi vdi md hinh SSIl: 7/12 trUdng hpp thi Qmax gi^m tU 10% den 33%; 5/12 trudng hop cdn lai Qmax tang tU 10% den 55%. Khi d d cirng dat nen tang len (md hinh SSI3), Qmax tang len va ludn vuOt tU 10% den 65% Qmax cua md hinh FB. Do dd, neu cdng trinh dupe flat tren dat nen cd dp cdng eao thi Qmax se tang len dang ke neu x^t den anh hudng ciia SSI.
LUc doc Idn nhat chan edt (Nmax): ddi vdi md hinh SSIl, Nmax tang til 10% den 35%.
Khi dp cdng dat nen tang len [md hinh SSI3) thi Nmax giam xuong vk giam den gan b l n g Nmax cua md hinh FB. NhUvay, neu cdng trinh duoe dat tren dat nen cd dp cdng khdng cao thi Nmax se tang len dang ke neu xet den anh hudng eiia SSL
5. Ket l u ^ n
Md hinh tinh toan cd xet din knh hUdng do tuong tac giUa dat nen va ket cau cho thay rd nhung diem manh:
• Md phdng dupe he ket cau lam viec ddng thdi rat sat vdi thuc te {ket eau ben tren+ket eau mdng+dat nen).
• Cac 16 xo duoc sir dung trong m d hinh cd Ung x d phi tuyen va khdng dan hdi nen phan anh duoc phkn Ung eiia dat nen thay ddi lien tue khi edng trinh chm tai trong ddng dat.
• D p eUng eua dat nen, mdt thdng sd quan trong va quyet dinh den ket quk bai tokn, da cd the dUOc xem xet cu the trong md hinh nay.
Khi xet den knh hudng do tUong tac giCTa dat nen va ket eau vao md hinh tinh toan t h i :
• Chu ki dao ddng eua he ket cau se tang len dang ke [ed trudng hpp tang den 98%). Neu dp cdng cua ket eau ben tren cang Idn thi chu ki dao ddng cang Idn (ed trUdng hop tang den 155%). Khi dd cdng dat nen t^ng len thi chu ki dao ddng se g i l m xudng.
• Chuyen vi dinh theo phuang ngang tang len {cd trudng hpp tang den 56%). Khi d d cdng dat nen tang len thi chuyen Vj dinh cd xu hUdng giam xudng
• Npi iue cua cdt gida nhieu khk nang se tang len. Dac biet la lUe eat (cd trUdng hpp tang den 65% khi edng trinh dupc dat tren dat n^n tot) va lUc doc (cd trudng hop tang den 35% khi edng trinh dupe dat tren dat nen khdng tdt).
• Ndi lUe eiia cot gdc g i l m di dang ke. Khi d p cu'ng dat nen tang len thi npi lUc eua cdt goc cd xu hudng tang l&n nhung gia trj npi lUc van nhd hOn so vdi md hinh khdng xet den SSI.
• Su phan bd lai ndi lUc giCra cac cdt t u a n g ddi phdc tap. Phkn Ung ciia cdt gdc va cdt gida la khac nhau.
Blng 12. Luc c i t Idn nhat chan cdt giu'a (kN) M o m e n t m a x
C H A L F A N T VALLEY 4 t a n g B t a n g 12 t a n g M o m e n t m a x
C O A L I N G A 4 t a n g 8 t a n g 12 t a n g
C o t giiJa FB 2 0 1 0 3 4 9 1 632.2
S S I l 1S2 9 3 2 2 5 4 1 0 . 3
SSI2 169.5 3 6 8 . 8 5 0 6 0
SSB 196-3 356.6 600.9 C o t g i u a FB 5 3 9 6 8 7 1 7 760,2
5SI1 301.5 4 0 8 , 9 6 4 2 . 6
SS12 4490 634 7 681.0
SSB 523,0 824 6 743 0
Moment max IMPERIAL
VALLEY 4 tang Stang 12 tang Moment max LOMA PRIETA 4 tang 8 tang 12 tang
Cot giiia FB 338-8 689-8 700.9
5SI1 222.6 385.1 821 3
SSI2 300-7 514.9 721.8
5513 352-6 622-6 800-6 Cot giOa FB 387-5 665.7 730.9
5SI1 271.9 337.2 665.4
5512 407.5 504.8 637,7
SSB 4S9 9 545.0 705.8 B l n g 13. LUc d p e Idn n h a t ehan cot glC(a{kN)
Luc cSl max CHALFANT VALLEY 4t3ng Stang 12 tang Lire cSt max COALINGA 4 tang Stang 12 tang
Cot giCIa FS 76.1 120.3 241.0
SSIl 82,4 187,7 191 8
SSI2 951 219,5 226 9
SSB 109,1 199.1 272 8 Cot giua FB 205,0 278.5 269.0
SSIl 165 8 186,3 271,9
S5I2 224 9 253.0 303.1
5513 248 1 3216 310,4
lUccatmax IMPERIAL VALLEY 4 tang Stang 12 tang LOMA PRIETA
4 tang Btang 12 tang
FB 153 2 261 1 256.3
FB 171,9 234 6 270 9
Cot 5511 129.6 175 3 297,8 Cot SSIl 1542 163.4 293.5
giCia 5512 162 9 236 3 301.5 giOa
SSI2 209 5 248,6 300,5
5513 1771 282 9 341 4
5513 228 6 262 3 333 6 B l n g 11. Moment Idn nhat ehan cdt gida (kN.m)
CHALFANT VALLEY 4tSng Stang 12 tang COALINGA
4 tang Stang 12 tang
Cotgiila FB 659.4 1286.1 1925,5
F8 6879 1351.7 1993 6
5511 730.1 1567.9 2 1 4 2 9
SS(2 6 6 6 . 9 1407.6 1997-1
SSt3 661-0 1314.1 1958 8 C o t g i O a 5sn 8 5 7 7 1 8 2 1 8 2 5 9 5 . 4
SS!2 748,8 1 S33.6 2 2 1 3 . 5
SSB 7 7 1 . 4 1516-0 2064-2
IMPERIAL VALLEY 4 t a n g S t a n g 12 t a n g
L O M A PRIETA 4 t a n g 8 t a n g 12 t a n g
C o t giCia FB 6 6 7 0 1293-5 1919.6
SSIl 7 5 8 . 4 1 7 5 4 9 2 6 2 6 7
SS12 6 8 5 , 2 1 4 4 8 . 6 2 1 6 5 0 C o t g i i l a FB 686-1 1324.6 1931.0
5511 777.3 1 7 0 6 2 2 3 6 9 8
SSI2 758-9 1 4 5 7 6 2 1 2 1 8
SSI3 6 5 9 . 0 1 3 4 5 4 2 0 4 8 3
5513 7 0 4 . 9 1 3 6 6 . 9 2 0 7 7 S
TAUIEUTHAMKHJIO
1 . 0 h b t a , S . , "Influences o f t h e foundation types and the ground conditions on the natural period of actual buildings' Transaction of AIJ.pp 2 J - i l , 1 9 8 2 ,
2. Vardanega, C„ "Effect of foundation fleKibility on the seismic response of panel buildings" The Seventh Woitd Conference on Earthquake Engtneering, Istanbul, Turkey, Vol. 6, pp 105-112,1980,
3. Stewart, J. P, Seed, R. B., and Fenves, G L,"Seismic soil- structure interaction in buddings. II: Empncal findings" Journal of Geotechmcal and Geo-environmental Engineering, ASCE, Vol.
125, N o i , pp. 38-48,1999.
4. http.//opensees.berkeley,edu/wiki/indexphp/
OpenSees_User
5. Raychowdhury, R, "Nonlinear Winkler-based Shallow
foundation Mode! for Perfomiance Assessment of Seismically loaded Structures", PhD Dissertation, University of California, San Diego, 2008.
6. Ahmed, A. f. and Hamdy, H. A., "Contnbution of soil- stiucture interaction to seismic response of buildings" Journal of Civil Engineenng, KSCE, V o l , 17, No. 5, pp, 959-971,2013.
7 R. Clough, and J Penzien., "Dynamics of Stnicture", Second Edition, McGraw-Hill, I n c , ISBN 0-07-011394-7,1993.
8. "Soil - structure interaction" CSI technical papers.
Computers and Structures Inc
