Buildingscomposedofcold-formedsteel(CFS)framingsystemshavebecomepopularinmanypartsof the world.Light-gaugeCFSframescanbebuiltupfromC-shapedsectionsandlaterallybracedwith tension-only thinstrapmembers.Recentresearchhasraisedmanyconcernsaboutthelateral performanceoftheselightwallsystemsinregionsofhighseismicactivity.Thispaperfocusesonthe failure modesofdifferentsystemsandonthemainfactorscontributingtotheductileresponseofthe CFS walls.Theaimistoensurethatthediagonalstrapsyieldandrespondplasticallywithasignificant drift, therebypreventinganyriskofbrittlefailuresuchasconnectionfailureorcolumnbuckling.Several superior connectiondetailsarethenproposed,whichprovideareliablelateralperformanceevenin large lateraldeformationsbyusingperforatedstrapsand/orbracketmembersinfourcornersofthe wall.Performanceoftheproposedsystemsisevaluatedbyexperimentaltestsonfull-scale2.4m _2.4m and 1.2m _2.4mspecimensunderaparticularcyclicloadregime. MethodBofASTME2126 05standardwasselectedaslateralloadingregime,whichintroducesa progressivelyincreasingcyclicloadingwithtwostabilizedcyclesateachdisplacementamplitude.In order tomaximizetheprecisionoftheresult,eachspecimenwasconnectedtothetestingrigbyhigh strength bolt.Thetestsshowedthatallofthenewproposedsystemscanprovidereliableresponsewith good ductilityandmaintaintheirlateralandverticalload-bearingabilitiesuptoarelativelateral displacementsof3.3%,whichwasthelimitofthetestingrig. دانلود مقاله
16فوریه
