建筑结78课件讲解

建筑结构ArchitecturalStructures轴心受压构件承载力计算CalculationofAxialLoad-bearingCapacityforCompressionMembers4.3柱构件设计ColumnDesign目录

CONTENTS轴心受压构件截面设计DesignofCross-sectionforAxiallyLoadedCompressionMembers1轴心受压构件截面复核CheckingofCross-sectionforAxiallyLoadedCompressionMembers2某百货大楼塌陷Adepartmentstorecollapsed事故原因AccidentCause肆意改动设计图纸：四层写字楼改为五层商场；Arbitrarymodificationofdesigndrawings:convertingafour-storyofficebuildingintoafive-storyshoppingmall;更改立柱尺寸、偷工减料；Theunauthorizedalterationofpillardimensionsandtheuseofsubstandardmaterials;施工错误：楼板钢筋装错位置；Constructionerror:Reinforcementbarsinthefloorslabinstalledatincorrectpositions;改变用途，暖气设备增加重量；Theheatingequipmenthasgainedweightduetoachangeinitsintendeduse;超载：空调设备冷水机注水后超载。Overload:Thewaterchilleroftheairconditioningequipmentisoverloadedafterbeingfilledwithwater.事故原因AccidentCause12345事故原因AccidentCause800mm600mm无梁楼板结构，竖向荷载靠柱子承担；Itfeaturesaflat-slabstructurewithoutbeams,withtheverticalloadsprimarilysupportedbycolumns;柱的承载能力大大减低,为大楼倒塌埋下巨大隐患。Thusplantingahugesafetyhazardthateventuallyledtothecollapseofthebuilding.（16）（8）遵纪守法Observelawanddiscipline底线思维Bottom-linethinking工程伦理Engineeringethics思考：案例中立柱尺寸和钢筋数量减少，其承载力降低，请大家思考承载力和什么因素有关？这些因素又如何在计算公式中体现呢？Thinking:Inthecase,whenthedimensionsofthecolumnandtheamountofreinforcementarereduced,itsbearingcapacitydecreases.Pleaseconsiderwhatfactorsarerelatedtothebearingcapacityofthecolumn?Andhowarethesefactorsreflectedinthecalculationformula?轴心受压构件承载力计算基本公式BasicFormulaforCalculatingtheBearingCapacityofAxiallyCompressedMembers《混凝土结构设计规范》CodeforDesignofConcreteStructures

轴向压力设计值Thedesignvalueforaxialcompressiveforce轴向受压构件的承载力Theload-bearingcapacityofanaxiallycompressedmember混凝土承载力Concretebearingcapacity钢筋承载力ReinforcementbearingcapacityhbA'sA轴心受压构件承载力计算基本公式BasicFormulaforCalculatingtheBearingCapacityofAxiallyCompressedMembers

0.9是可靠度调整系数0.9representsthereliabilityadjustmentfactor.φ为钢筋混凝土轴心受压构件的稳定系数φdenotesthestabilitycoefficientofthereinforcedconcreteaxialcompressionmember.fc为混凝土抗压强度设计值fcstandsforthedesignvalueofthecompressivestrengthoftheconcrete.轴心受压构件承载力计算基本公式BasicFormulaforCalculatingtheBearingCapacityofAxiallyCompressedMembers

A为构件的截面面积，当ρ>3%时，A改为（A-A's）Areferstothecross-sectionalareaofthemember，whenρ>3%,Aischangedto(A-A’s).fy´为钢筋的抗压强度设计值fy’isthedesignvalueofthecompressivestrengthofthereinforcingsteel.A´s为全部纵向受压钢筋的截面面积A’srepresentsthetotalcross-sectionalareaofallthelongitudinalcompressivereinforcementbars.轴心受压构件承载力计算基本公式BasicFormulaforCalculatingtheBearingCapacityofAxiallyCompressedMembers轴心受压构件截面设计DesignofCross-sectionforAxiallyLoadedCompressionMembers轴心受压承载力计算Calculatingthecompressivebearingcapacityforaxiallyloadedmembers截面设计Cross-sectiondesign截面复核Cross-sectionverification轴心受压构件截面设计DesignofCross-sectionforAxiallyLoadedCompressionMembersPARTONE轴心受压构件截面设计DesignofCross-sectionforAxiallyLoadedCompressionMembers已知构件尺寸b×h，轴向力设计值N，构件计算长度l0，材料强度等级fc及fy´,求：纵向受力钢筋As´Thedimensionsofthemember(b×h),thedesignvalueofaxialforceN,theeffectivelengthofthememberl0,andthestrengthgradesofthematerialfcandfy’areknown.ThetaskistodeterminetheareaAs’ofthelongitudinaltensilereinforcementsteel.01求稳定系数φ

Calculatethestabilitycoefficientφ

计算钢筋截面面积As’Calculatethecross-sectionalareaAs´ofthereinforcementsteel

验算配筋率ρ´Checkthereinforcementratioρ’01轴心受压构件截面设计DesignofCross-sectionforAxiallyLoadedCompressionMembers

验算配筋率ρ´Checkthereinforcementratioρ’

选配钢筋Selectingandmatchingreinforcingbars

01轴心受压构件截面设计DesignofCross-sectionforAxiallyLoadedCompressionMembers02已知：构件尺寸未知，轴向力设计值N，构件计算长度l0，材料强度等级fc

，fy’，求：纵筋截面面积As’。Given:Memberdimensionsareunspecified,designaxialforcevalueN,membercalculationlengthl0,materialstrengthgradefc,andyieldstrengthfy’,solvefor:thecross-sectionalareaAs’ofthelongitudinalreinforcingsteel.轴心受压构件截面设计DesignofCross-sectionforAxiallyLoadedCompressionMembers02假定φ=0.8~1.0，配筋率ρ´=1%Assumethestabilitycoefficientφtobewithintherangeof0.8to1.0,andsetthereinforcementratioρ´at1%.

确定b和hOnceAisdetermined,identifythewidth