Soil-structure interaction of seismically isolated bridge structure during very strong ground motion

Transcription

1 IABSE-JSCE Joint Confeene on Advanes in Bide Enineein-III, Ast 1-, 15, Daa, Banlades ISBN: Ain, Oi, Biyan, Ueda eds wwwiabse-bdo Soil-stte inteation of seisially isolated bide stte din vey ston ond otion M Asiqzzaan Saint Lois Univesity, Missoi 63143, USA MT Isla Banlades Univesity of Enineein and Tenoloy, Daa 1, Banlades MM Raan & KJ Hon Kooin Univesity, Seol, 136-7, Koea ABSTRACT: Soil-stte-inteation SSI as a sinifiant effet on seisially isolated bide stte din vey ston ond otion Beain ads in between ie and ide an otate oe tan allowable desin otation din exteely ston ond otion wi as eally a detiental effet on te total dislaeent of bide de Te total esonse of te sestte old be oe daneos in ase of vey lae ide setion Hee, in tis esea a silified odel is onstted to esent te wole bide syste onsidein soil-stte inteation Te odel onsists five deee of feedos: tanslation and otation of fondation, tanslation of ie and tanslation and otation of isolation ass Te eqations of otion fo te wole bide syste ae deived in feqeny doain by assin soil stiffness and dain onstants Te silified odel is n nde finite eleent envionent in ABAQUS Paaeti stdies ae e-foed based on te onstted ABAQUS odel Te fos of te esea is to find ot te ontibtin odes of te odel de to SSI effet on bide stte 1 NOTATIONS, : ide and ie ass esetively,,, and,,, and : : : Heit of ie ide, ie, fondation tanslational, fondation otational and beain ad otational stiffness oeffiient esetively ide, ie, fondation tanslational, fondation otational and beain ad otational dain oeffiient esetively : Heit of ide ide, ie, fondation tanslational, ide otational and fondation,,, and : otational deee of feedo esetively t, t : Total dislaeent of te ie ass and ide : Dislaeent de to ond otion INTRODUCTION Te seisi iat on te sttes wit lae eit is always vioosly doinant isse in te field of eatqae enineein In te bide enineein, te otation de to lae ide web in esene of soil stte inteation is noally ovelooed by te bide eninees Tis otation in ide de to soe seisi ativity old be an ieative isse in lobal stability of bide Stdies involvin dynai soil stte inteation SSI ae ate olex bease of te non-ooeneity, nonlineaity and sei-infinite extent of te soil, as well as seveal diffilties in olin te soil and te soted stte Te liteate is ate extensive on te toi A oeensive eview of te liteate on soil fondation inteation an be fond in te aes by azetas [1], Antes and Syaos [] and Syaos [3] Te bide-soil syste adoted in te analysis is sown in Fi 1 Te bide de is onsideably stiffe tan te isolation beains, wi ae sed fo te seisi isolation of te sestte, and te ies ae 1

2 fonded on a sei-infinite soil edi to assless, sfae fondations Te san lents ae qite sot so tat te wole syste is vibatin in te sae way Fte, te ass, of te ies is sinifiantly salle tan te ass a of te tibtay bide de Colyin also wit te onet of seisi isolation desin, all te bide oonents, ote tan te isolation beains tat ae aateized by elasto-lasti beavio, ae assed to eain elasti din an eatqae event in tis ae Te syste is exited by a seisi ond otion atin alon te tansvese axis of te bide Te ossible otation is te ide is sown in Fi It sold be noted tat te soe of tis stdy is liited to te ela bides [AASHTO, Bides wit abt anes of stiffness o ass distibtion ae not oatible wit te ose of tis ae and so ae exlded Fie 1 Steel ide bide wit dee web size Fie Possible otation in beain ad din vey ston ond otion 3 PREVIOUS SSI MODEL FOR BRIDE STRUCTURE In te ast esea, otation of beain ad was not onsideed wi an ede te axi dislaeent in lae ide [4] Tis edtion in axi dislaeent ay ase soe oble to bide enineein in estiatin te total ide dislaeent din vey ston ond otion Te evios SSI odel fo bide and its dislaeent atten ae sown in Fi 3 and Fi 4 13

3 14 Fie 3 Syaos et al odel fo SSI Fie 4 Dislaeent of Syaos et al odel din ond otion Based on te Fi 4, te eqation of otion an be deived in atix as Eq 1 1 Fie 5 Poosed SSI odel lae ide bide Fie 6 Dislaeent of oosed SSI odel din ond otion b

4 15 4 PROPOSED SSI MODEL FOR BRIDE STRUCTURE In te oosed SSI odel fo bide stte, te otation of beain ad was taen into aont in estiatin te total axi dislaeent in ide din vey ston ond otion Te oosed silified odel of soil-stte inteation fo bide stte is sown in Fi 5 Te dislaeent beavio of te silified odel is sown in Fi 6 Te eqations of otion wee deived based on te Fi 6 Te eqation of otion is efoatted in atix fo sown in Eq 5 COMPARISON BETWEEN PROPOSED AND PREVIOUS MODEL 51 Udates in Poosed Model Lae ide dislaeent is te ajo onen din ajo eatqae ond otion To define lae ide dislaeent, te otation in beain ad was onsideed into aont Te otation in beain ad an bin lobal instability in te wole stte In tis stdy, dee ide is onsideed to onside te otational inetia of te ide 5 Exale Poble Considein eit of te ie = 15 ; eit of te ie = 8 ; ie ass, = 15 ; ide ass, = ; ie sin oeffiient, =14e11 N/; beain ad sin oeffiient, = 5e7 N/; fondation oizontal sin oeffiient, = 48e9 N/; fondation otational sin oeffiient, = 13e8 N; beain ad oin sin oeffiient, = 13e9 N; ie dain oeffiient, = e8 N-s/; beain ad dain oeffiient, = 58e6 N-s/; fondation oizontal dain oeffiient, = 4e6 N-s/; fondation otational dain oeffiient, = 48e6 N-s-; beain ad oin dain oeffiient, = 48e5 As te axi stte esonse is te ain onen in tis stae of esea, esonse at te sttal ass is deteined de to eatqae exitations El Cento 6 RESULTS AND CONCLUSIONS Based on te finite eleent analysis in ABAQUS, te esonses in ide fo silified SSI odel ae sown in Fi 7 to Fi 9

5 Fie 7 Total ide dislaeent fo ABAQUS Fie 8 Total ide aeleation fo ABAQUS Fie 9 Total ide veloity fo ABAQUS It an be easily seen tat te otation in beain is an iotant fato to et lae otation in te se stte REFERENCES [1] azetas, 1983 Analysis of aine fondation vibations: state of te at Intenational Jonal of Soil Dynais and Eatqae Enineein, 1, -4 [] Besos, D E, & Ananostoolos, S A 1997 Cote analysis and desin of eatqae esistant sttes: a andboo WIT Pess [3] Syaos, C C 3 Soil Stte Inteation in Patie In Bonday Eleent Metods fo Soil-Stte Inteation 35-7 Sine Netelands [4] Syaos, C C, & Vlassis, A Effet of soil-stte inteation on seisially isolated bides Jonal of eatqae enineein, 63,