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1、4.4ReinforcedConcreteColumn4.4钢筋混凝土柱AxialCompression轴向受压承受压力的构件被称作柱子Columnsaredefinedasmembersthatcarryloadschieflyincompression.Inadditiontothecommontypeofcompressionmember,i.e.verticalelementsinstructures,compressionmembersincludearchribs,rigidframemembersinclinedorotherwise,compressionel
2、ementsintrussesorshell.除了一般的受压构件,即结构中的竖向构件,受压构件还包括拱肋,斜的刚架构件,桁架或壳结构中的受压构件。Compositecompressionmembersreinforcedlongitudinallywithstructuralsteelshapes,pipe,ortubing,withorwithoutadditionallongitudinalbars,andvarioustypesoflateralreinforcement.配置纵向结构型钢、钢管或管形材料并配有各种类型横向钢筋的复合受压构件,无论是否配置附加的纵向钢筋。
3、steelshapes型钢Themainreinforcementincolumnsislongitudinal,paralleltothedirectionoftheload,andconsistsofbarsarrangedinasquare,rectangular,orcircularpattern.柱中的主要受力筋为纵向钢筋,与荷载作用方向平行,沿正方形、矩形或环形布置。Lateralreinforcement,intheformofindividualrelativelywidelyspacedtiesoracontinuouscloselyspacedspiral
4、,servesseveralfunctions.横向钢筋为具有较大间距单个箍筋或连续的近间距的螺旋箍,它具有若干功能。forone作为其中一个;举例来说Forthispurpose,longitudinalandtransversesteeliswiredtogethertoformcages,whicharethenmovedintotheformsandproperlypositionedbeforeplacingtheconcrete.因此,将纵向钢筋和箍筋绑扎在一起,形成钢筋骨架,然后将其移入模板中,在浇筑混凝土前正确摆放。Foranother,transverser
5、einforcementisneededtopreventthehighlystressed,slenderlongitudinalbarsfrombucklingoutwardbyburstingthethinconcretecover.另外,箍筋能够防止应力较大的、细长纵筋向外弯曲,崩裂单薄的混凝土保护层。BehaviorofAxiallyLoadedShortColumn轴心受压短柱的特性Whenanaxialloadisappliedtoareinforcedconcreteshortcolumn,theconcretecanbeconsideredtobehavee
6、lasticallyuptoalowstressofabout(1/3).当荷载作用在钢筋混凝土短柱形心时,应力低于,混凝土被认为具有弹性特性。Atthisloadtheconcretefailsbycrushingorshearingoutwardalonginclinedplanes,andthelongitudinalsteelbarsfailbybucklingoutwardbetweenties,asshowninFigure4.26(a).普通箍筋柱在荷载Na作用下破坏。在此荷载下,由于混凝土压碎或向外沿斜面受剪破坏,纵筋由于在箍筋之间向外弯曲而破坏,如图(4.2
7、6a)所示。Itisatthisstagethattheconfiningactionofthespiralhasasignificanteffect,andifsizablespiralsteelisprovided,theloadwillultimatelyfailthecolumnbycausingthespiralsteeltoyield.正是在这个阶段,螺旋箍发挥着重要的约束作用。如果配置大量的螺旋箍,当荷载使螺旋筋屈服时,柱子发生破坏。Bothtiedandspirallyreinforce