建筑结66课件讲解

建筑结构ArchitecturalStructures受压构件的破坏特征FailureCharacteristicsofCompressedMembers4.2柱构件设计ColumnDesign目录

CONTENTS轴心受压构件的受力性能及破坏特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers1偏心受压构件的破坏特征FailureCharacteristicsofEccentricallyLoadedCompressionMembers2柱截面Columnsection纵筋Longitudinalbar混凝土Reinforcedconcrete柱Column按轴力作用线位置分Accordingtotheaxialforceasthelineposition轴心受压构件Axialcompressionmembers偏心受压构件Eccentricallyloadedcompressionmembers受压构件的分类ClassificationofCompressionMembers轴心受压构件AxialcompressionmembersN轴向压力作用线与构件截面形心轴线重合。Whenthelineofactionoftheaxialcompressiveforcecoincideswiththecentroidofthecross-sectionalareaofthemember.受压构件的分类ClassificationofCompressionMembers轴向压力作用线与构件截面形心不重合；Whenthelineofactionoftheaxialcompressiveforcedoesnotcoincidewiththecentroidofthecross-section.偏心受压构件Eccentricallyloadedcompressionmembers在构件截面上，同时作用有轴向压力和弯矩。Whenbothaxialcompressiveforceandbendingmomentactsimultaneouslyonthecross-sectionofthemember.NNM受压构件的分类ClassificationofCompressionMembers偏心受压构件EccentricallyloadedcompressionmembersNN单向偏心构件Uniaxialeccentricallycompressedmembers双向偏心构件Biaxialeccentricallycompressedmembers按轴向压力作用线位置分:Accordingtothepositionoftheaxialpressureline.受压构件的分类ClassificationofCompressionMembers轴心受压构件的受力性能及破坏特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembersPARTONE轴心受压构件的受力性能及破坏特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers由于构件制作误差、轴线偏差及混凝土材料的非均质性等原因，理想的轴心受压构件几乎不存在，往往存在一定的初始偏心距。Duetofactorssuchasmanufacturingerrorsincomponents,axisdeviation,andthenon-homogeneityofconcretematerials,anidealaxiallyloadedcompressionmemberhardlyexists,andthereoftenexistsacertaininitialeccentricity.内柱Innercolumn当偏心距很小时，可按轴心受压构件来计算，如框架结构中的内柱。Whentheeccentricityisverysmall,internalcolumnsinframestructurescanbecalculatedasaxiallycompressedmembers.轴心受压构件的受力性能及破坏特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers短柱Shortcolumn长柱

Longcolumn轴心受压构件的受力性能及破坏特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers短柱破坏Theshortcolumnfailure荷载较小时，钢筋与混凝土共同受力，变形主要为弹性变形。Whentheloadissmall,steelreinforcementandconcretebearforcestogether,andthedeformationisprimarilyelasticdeformation.轴心受压构件的受力性能及破坏特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers短柱破坏Theshortcolumnfailure随着荷载增大，混凝土应力增长变慢，钢筋应力越来越大，并先达到屈服。Astheloadincreases,thegrowthrateofconcretestressslowsdownwhilethereinforcementstresskeepsincreasingandreachesyieldfirst.轴心受压构件的受力性能及破坏特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers短柱破坏Theshortcolumnfailure钢筋屈服后，压力全部由混凝土承担，柱子表面出现纵向裂缝，混凝土保护层开始剥落。Aftertheyieldingofsteelreinforcement,allthecompressivestressisbornebytheconcrete,longitudinalcracksappearonthesurfaceofthecolumn,andtheconcreteprotectivelayerbeginstospall.最终纵筋压屈外凸，混凝土被压碎崩裂而破坏。Thefinallongitudinalreinforcementbucklesoutward,causingtheconcretetocrushandspall,leadingtofailure.轴心受压构件的受力性能及破坏特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers短柱中的钢筋和混凝土的抗压强度都能得到充分利用，属于材料破坏。Boththecompressivestrengthofsteelreinforcementandconcreteinshortcolumnsarefullyutilized,whichfallsundermaterialfailure.短柱的纵向弯曲影响很小，可忽略不计。Thelongitudinalbendingeffectonshortcolumnsisminimalandcanbeneglected.轴心受压构件的受力性能及破坏特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers初始偏心的影响不容忽视。Theeffectofinitialeccentricitycannotbeneglected.受压长柱Compressedlongcolumns轴心受压构件的受力性能及破坏特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers受压长柱Compressedlongcolumns初始偏心距的存在，使构件产生侧向挠曲；Duetothepresenceofaninitialeccentricity,thememberexperienceslateraldeflection.使得长柱在弯曲和轴向压力共同作用下发生破坏。Longcolumnsunderthecombinedactionofbendingandaxialcompressiveforcessufferdamage.侧向挠曲进一步加大初始偏心距；Thislateraldeflectionfurtherincreasestheinitialeccentricity.轴心受压构件的受力性能及破坏特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers受压长柱Compressedlongcolumns凹边出现纵向裂缝；Longitudinalcracksfirstappearontheconcaveside.混凝土压碎，纵筋压弯外凸，侧向挠度急速发展；Followedbycrushingoftheconcrete,outwardbucklingofthelongitudinalreinforcementundercompression,rapiddevelopmentoflateraldeflection.轴心受压构件的受力性能及破坏特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers受压长柱Compressedlongcolumns柱子失去平衡，凸边混凝土拉裂而破坏。Thecolumnlosesitsbalance.Theconvexsideconcretethenundergoestensilesplittingandfails.轴心受压构件的受力性能及破坏特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers在同等条件下（即截面相同，配筋相同，材料相同），长柱的承载力低于短柱。Underthesameconditions(i.e.,withidenticalcross-sections,reinforcement,andmaterials),theload-bearingcapacityoflongcolumnsislowerthanthatofshortcolumns.

长柱承载力Theload-bearingcapacityoflongcolumns短柱承载力Theload-bearingcapacityofshortcolumns轴心受压构件的受力性能及破坏特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers＜如何区分？Howdowedistinguishthem?长柱？Longcolumn？短柱？Shortcolumn？轴心受压构件的受力性能及破坏特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers长细比——构件的计算长度l0与截面最小回转半径i之比。Theslendernessratio——itreferstotheratioofthemember’seffectivelengthl0toitsminimumradiusofgyrationi.

长细比Theslendernessratiol0

——构件计算长度与构件两端支承情况有关。Theeffectivelengthofthememberdependsonthesupportconditionsatbothends.楼盖类型Floorsystemtypes柱段Columnsegment计算长度l0Calculatelengthl0现浇楼盖Cast-in-placeFloorSlab底层柱段Bottomlayercolumnsegment1.0H其余各层柱段Columnsegmentsfortheremaininglayers1.25H装配式楼盖PrefabricatedFloorSlab底层柱段Bottomlayercolumnsegment1.25H其余各层柱段Columnsegmentsfortheremaininglayers1.5H轴心受压构件的受力性能及破坏特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers一般截面

Generalcross-sectioni——

截面最小回转半径irepresentstheminimumradiusofgyration轴心受压构件的受力性能及破坏特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembersbhd

矩形

Rectangular圆形

Circular短边尺寸Thedimensionoftheshorterside截面直径Thediameterofthecross-section轴心受压构件的受力性能及破坏特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers短柱Shortcolumnl0bd矩形截面

Rectangularcross-section

圆形截面Circularcross-section

任意截面Anycross-section

轴心受压构件的受力性能及破坏特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers长柱Longcolumn矩形截面

Rectangularcross-section

圆形截面Circularcross-section

任意截面Anycross-section

轴心受压构件的受力性能及破坏特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembersb=1000h=1200l0=6400Ab=400l0=6400B长细比l0/b=6.4Theslendernessratio<8长细比l0/b=16Theslendernessratio>8短柱Shortcolumn长柱Longcolumn轴心受压构件的受力性能及破坏特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembersA柱ColumnAB柱ColumnB截面尺寸Cross-sectionaldimensions绝对长度Absolutelength轴心受压构件的受力性能及破坏特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers《混凝土结构设计规范》采用稳定系数φ表示长柱承载力的降低程度。TheSpecificationforDesignofConcreteStructuresadoptsthestabilitycoefficientφtorepresentthedegreeofreductionintheload-carryingcapacityoflongcolumns.长细比愈大，承截力愈低。Thelargertheslendernessratio,thelowertheload-bearingcapacity.＜承载力Theload-carryingcapacity轴心受压构件的受力性能及破坏特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers≤810121416182022242628≤78.510.5121415.517192122.524≤2835424855626976839097≤1.00.980.950.920.870.810.750.700.650.600.563032343638404244464850262829.5313334.536.5384041.5431041111181251321391461531601671740.520.480.440.400.360.320.290.260.230.210.19

钢筋混凝土构件的稳定系数φ表TableofStabilityCoefficientφforReinforcedConcreteMembers长细比↑Theslen