建筑結66課件講解

建筑結構ArchitecturalStructures受壓構件的破壞特征FailureCharacteristicsofCompressedMembers4.2柱構件設計ColumnDesign目錄

CONTENTS軸心受壓構件的受力性能及破壞特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers1偏心受壓構件的破壞特征FailureCharacteristicsofEccentricallyLoadedCompressionMembers2柱截面Columnsection縱筋Longitudinalbar混凝土Reinforcedconcrete柱Column按軸力作用線位置分Accordingtotheaxialforceasthelineposition軸心受壓構件Axialcompressionmembers偏心受壓構件Eccentricallyloadedcompressionmembers受壓構件的分類ClassificationofCompressionMembers軸心受壓構件AxialcompressionmembersN軸向壓力作用線與構件截面形心軸線重合。Whenthelineofactionoftheaxialcompressiveforcecoincideswiththecentroidofthecross-sectionalareaofthemember.受壓構件的分類ClassificationofCompressionMembers軸向壓力作用線與構件截面形心不重合；Whenthelineofactionoftheaxialcompressiveforcedoesnotcoincidewiththecentroidofthecross-section.偏心受壓構件Eccentricallyloadedcompressionmembers在構件截面上，同時作用有軸向壓力和彎矩。Whenbothaxialcompressiveforceandbendingmomentactsimultaneouslyonthecross-sectionofthemember.NNM受壓構件的分類ClassificationofCompressionMembers偏心受壓構件EccentricallyloadedcompressionmembersNN單向偏心構件Uniaxialeccentricallycompressedmembers雙向偏心構件Biaxialeccentricallycompressedmembers按軸向壓力作用線位置分:Accordingtothepositionoftheaxialpressureline.受壓構件的分類ClassificationofCompressionMembers軸心受壓構件的受力性能及破壞特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembersPARTONE軸心受壓構件的受力性能及破壞特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers由于構件制作誤差、軸線偏差及混凝土材料的非均質性等原因，理想的軸心受壓構件幾乎不存在，往往存在一定的初始偏心距。Duetofactorssuchasmanufacturingerrorsincomponents,axisdeviation,andthenon-homogeneityofconcretematerials,anidealaxiallyloadedcompressionmemberhardlyexists,andthereoftenexistsacertaininitialeccentricity.內柱Innercolumn當偏心距很小時，可按軸心受壓構件來計算，如框架結構中的內柱。Whentheeccentricityisverysmall,internalcolumnsinframestructurescanbecalculatedasaxiallycompressedmembers.軸心受壓構件的受力性能及破壞特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers短柱Shortcolumn長柱

Longcolumn軸心受壓構件的受力性能及破壞特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers短柱破壞Theshortcolumnfailure荷載較小時，鋼筋與混凝土共同受力，變形主要為彈性變形。Whentheloadissmall,steelreinforcementandconcretebearforcestogether,andthedeformationisprimarilyelasticdeformation.軸心受壓構件的受力性能及破壞特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers短柱破壞Theshortcolumnfailure隨著荷載增大，混凝土應力增長變慢，鋼筋應力越來越大，并先達到屈服。Astheloadincreases,thegrowthrateofconcretestressslowsdownwhilethereinforcementstresskeepsincreasingandreachesyieldfirst.軸心受壓構件的受力性能及破壞特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers短柱破壞Theshortcolumnfailure鋼筋屈服后，壓力全部由混凝土承擔，柱子表面出現(xiàn)縱向裂縫，混凝土保護層開始剝落。Aftertheyieldingofsteelreinforcement,allthecompressivestressisbornebytheconcrete,longitudinalcracksappearonthesurfaceofthecolumn,andtheconcreteprotectivelayerbeginstospall.最終縱筋壓屈外凸，混凝土被壓碎崩裂而破壞。Thefinallongitudinalreinforcementbucklesoutward,causingtheconcretetocrushandspall,leadingtofailure.軸心受壓構件的受力性能及破壞特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers短柱中的鋼筋和混凝土的抗壓強度都能得到充分利用，屬于材料破壞。Boththecompressivestrengthofsteelreinforcementandconcreteinshortcolumnsarefullyutilized,whichfallsundermaterialfailure.短柱的縱向彎曲影響很小，可忽略不計。Thelongitudinalbendingeffectonshortcolumnsisminimalandcanbeneglected.軸心受壓構件的受力性能及破壞特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers初始偏心的影響不容忽視。Theeffectofinitialeccentricitycannotbeneglected.受壓長柱Compressedlongcolumns軸心受壓構件的受力性能及破壞特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers受壓長柱Compressedlongcolumns初始偏心距的存在，使構件產(chǎn)生側向撓曲；Duetothepresenceofaninitialeccentricity,thememberexperienceslateraldeflection.使得長柱在彎曲和軸向壓力共同作用下發(fā)生破壞。Longcolumnsunderthecombinedactionofbendingandaxialcompressiveforcessufferdamage.側向撓曲進一步加大初始偏心距；Thislateraldeflectionfurtherincreasestheinitialeccentricity.軸心受壓構件的受力性能及破壞特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers受壓長柱Compressedlongcolumns凹邊出現(xiàn)縱向裂縫；Longitudinalcracksfirstappearontheconcaveside.混凝土壓碎，縱筋壓彎外凸，側向撓度急速發(fā)展；Followedbycrushingoftheconcrete,outwardbucklingofthelongitudinalreinforcementundercompression,rapiddevelopmentoflateraldeflection.軸心受壓構件的受力性能及破壞特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers受壓長柱Compressedlongcolumns柱子失去平衡，凸邊混凝土拉裂而破壞。Thecolumnlosesitsbalance.Theconvexsideconcretethenundergoestensilesplittingandfails.軸心受壓構件的受力性能及破壞特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers在同等條件下（即截面相同，配筋相同，材料相同），長柱的承載力低于短柱。Underthesameconditions(i.e.,withidenticalcross-sections,reinforcement,andmaterials),theload-bearingcapacityoflongcolumnsislowerthanthatofshortcolumns.

長柱承載力Theload-bearingcapacityoflongcolumns短柱承載力Theload-bearingcapacityofshortcolumns軸心受壓構件的受力性能及破壞特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers＜如何區(qū)分？Howdowedistinguishthem?長柱？Longcolumn？短柱？Shortcolumn？軸心受壓構件的受力性能及破壞特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers長細比——構件的計算長度l0與截面最小回轉半徑i之比。Theslendernessratio——itreferstotheratioofthemember’seffectivelengthl0toitsminimumradiusofgyrationi.

長細比Theslendernessratiol0

——構件計算長度與構件兩端支承情況有關。Theeffectivelengthofthememberdependsonthesupportconditionsatbothends.樓蓋類型Floorsystemtypes柱段Columnsegment計算長度l0Calculatelengthl0現(xiàn)澆樓蓋Cast-in-placeFloorSlab底層柱段Bottomlayercolumnsegment1.0H其余各層柱段Columnsegmentsfortheremaininglayers1.25H裝配式樓蓋PrefabricatedFloorSlab底層柱段Bottomlayercolumnsegment1.25H其余各層柱段Columnsegmentsfortheremaininglayers1.5H軸心受壓構件的受力性能及破壞特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers一般截面

Generalcross-sectioni——

截面最小回轉半徑irepresentstheminimumradiusofgyration軸心受壓構件的受力性能及破壞特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembersbhd

矩形

Rectangular圓形

Circular短邊尺寸Thedimensionoftheshorterside截面直徑Thediameterofthecross-section軸心受壓構件的受力性能及破壞特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers短柱Shortcolumnl0bd矩形截面

Rectangularcross-section

圓形截面Circularcross-section

任意截面Anycross-section

軸心受壓構件的受力性能及破壞特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers長柱Longcolumn矩形截面

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圓形截面Circularcross-section

任意截面Anycross-section

軸心受壓構件的受力性能及破壞特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembersb=1000h=1200l0=6400Ab=400l0=6400B長細比l0/b=6.4Theslendernessratio<8長細比l0/b=16Theslendernessratio>8短柱Shortcolumn長柱Longcolumn軸心受壓構件的受力性能及破壞特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembersA柱ColumnAB柱ColumnB截面尺寸Cross-sectionaldimensions絕對長度Absolutelength軸心受壓構件的受力性能及破壞特征Load-bearingPerformanceandFailureCharacteristicsofAxiallyLoadedCompressionMembers《混凝土結構設計規(guī)范》采用穩(wěn)定系數(shù)φ表示長柱承載力的降低程度。TheSpecificationforDesignofConcreteStructuresadoptsthestabilitycoefficientφtorepresentthedegreeofreductionintheload-carryingcapacityoflongcolumns.長細比愈大，承截力愈低。Thelargertheslendernessratio,thelowertheload-bearingcapacity.＜承載力Theload-carryingcapacity軸心受壓構件的受力性能及破壞特征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

鋼筋混凝土構件的穩(wěn)定系數(shù)φ表TableofStabilityCoefficientφforReinforcedConcreteMembers長細比↑Theslen