Research on Improved Equivalent Diagonal Strut Model for Masonry-Infilled RC Frame with Flexible Connection

Abstract

Thereinforcedconcrete(RC)framewithmasonryinfillwallisoneofthemostcommonstructuralsystemsinmanycountries.It hasbeenwidelyrecognizedthattheinfillwallhassignificanteffectsontheseismicperformanceofRCframestructure.Duringthe Wenchuanearthquake(China2008),alotofinfilledRCframestructuressufferedseriousdamagesduetothedetrimentaleffects brought about by the infill wall rigidly connected to the surrounding frame. In order to solve this problem, flexible connection, introducedbyChinesedesigners,isrecommendedbytheupdatedChineseseismicdesigncode,becauseofitseffecttoreducethe unfavorable interaction between infill wall and frame. Although infilled RC frame structure with flexible connection has a lot of advantages,butbecauseofthelackofresearch,thisstructuretypeisseldomusedinpracticalengineering.Therefore,itisofgreat significancetoscientificallyinvestigateandanalyzetheeffectsofflexibleconnectiononstructurebehaviorsofinfilledRCframe.In this study, a macrofinite element numerical simulation method for infilled RC frame with flexible connection was investigated. Firstly, the effects of connection between infill wall and surrounding frame on in-plane behaviors of infilled RC frame were discussed.Secondly,basedondeeplystudyingtheequivalentdiagonalstrutmodelsforinfilledRCframewithrigidconnection,an improvedequivalentdiagonalstrutmodelforinfilledRCframewithflexibleconnectionwasproposed.Employedwithinversion analysistheory,theparameterintheproposedmodelwasestimatedthroughartificialfishswarmalgorithm.Finally,appliedwith the existing experiment results, a case study was conducted to verify the effectiveness and feasibility of the proposed model.