最新44鋼筋混凝土柱課件

44鋼筋混凝土柱44鋼筋混凝土柱AxialCompression軸向受壓承受壓力的構(gòu)件被稱作柱子Columnsaredefinedasmembersthatcarryloadschieflyincompression.AxialCompression軸向受壓承受壓力的構(gòu)件被2最新44鋼筋混凝土柱課件3最新44鋼筋混凝土柱課件4最新44鋼筋混凝土柱課件5最新44鋼筋混凝土柱課件6最新44鋼筋混凝土柱課件7最新44鋼筋混凝土柱課件8Forthispurpose,longitudinalandtransversesteeliswiredtogethertoformcages,whicharethenmovedintotheformsandproperlypositionedbeforeplacingtheconcrete.因此，將縱向鋼筋和箍筋綁扎在一起，形成鋼筋骨架，然后將其移入模板中，在澆筑混凝土前正確擺放。Forthispurpose,longitudinal9Foranother,transversereinforcementisneededtopreventthehighlystressed,slenderlongitudinalbarsfrombucklingoutwardbyburstingthethinconcretecover.另外，箍筋能夠防止應(yīng)力較大的、細(xì)長(zhǎng)縱筋向外彎曲，崩裂單薄的混凝土保護(hù)層。Foranother,transversereinfo10BehaviorofAxiallyLoadedShortColumn軸心受壓短柱的特性Whenanaxialloadisappliedtoareinforcedconcreteshortcolumn,theconcretecanbeconsideredtobehaveelasticallyuptoalowstressofabout(1/3).

BehaviorofAxiallyLoadedSho11當(dāng)荷載作用在鋼筋混凝土短柱形心時(shí)，應(yīng)力低于,混凝土被認(rèn)為具有彈性特性。

Atthisloadtheconcretefailsbycrushingorshearingoutwardalonginclinedplanes,andthelongitudinalsteelbarsfailbybucklingoutwardbetweenties,asshowninFigure4.26(a).當(dāng)荷載作用在鋼筋混凝土短柱形心時(shí)，應(yīng)力低于,混凝土被認(rèn)為具有12普通箍筋柱在荷載Na作用下破壞。在此荷載下，由于混凝土壓碎或向外沿斜面受剪破壞，縱筋由于在箍筋之間向外彎曲而破壞，如圖（4.26a）所示。普通箍筋柱在荷載Na作用下破壞。在此荷載下，由于混凝土壓碎或13Itisatthisstagethattheconfiningactionofthespiralhasasignificanteffect,andifsizablespiralsteelisprovided,theloadwillultimatelyfailthecolumnbycausingthespiralsteeltoyield.正是在這個(gè)階段，螺旋箍發(fā)揮著重要的約束作用。如果配置大量的螺旋箍，當(dāng)荷載使螺旋筋屈服時(shí)，柱子發(fā)生破壞。Itisatthisstagethatthe14BothtiedandspirallyreinforcedcolumnsbehavesimilarlyTiedcolumnfailssuddenlyYieldpoint(Spirallyreinforcedconcreteshellspallsoff)SpirallyreinforcedcolumnshowsabilitytodeformpriortofailureDeformationNaloadBothtiedandspirallyreinfo15(a)Unsupportedbarsbuckle(b)ConcreteshellspallsoffFailureoftiedandspirallyreinforcedconcretecolumn(a)Unsupportedbarsbuckle16ShortColumnsunderCombinedAxialForceandMoment軸力及彎矩共同作用下的短柱

ShortColumnsunderCombinedA17WhenamemberissubjectedtocombinedaxialcompressionNandmomentM,suchasinFigure4.28(a),itisusuallyconvenienttoreplacetheaxialloadandmomentwithanequalloadNappliedateccentricity,asinFigure4.28(b).

Whenamemberissubjectedto18當(dāng)柱子承受軸力N以及彎距M的共同作用時(shí)，如圖4.28a，通常用軸力N作用在距離軸心e=M/N處取代構(gòu)件承受的軸力和彎矩，如圖4.28b所示，是一種很簡(jiǎn)便的方法。NNeM當(dāng)柱子承受軸力N以及彎距M的共同作用時(shí)，如圖4.28a，通常19Balancedfailure界限破壞Underthismodeoffailure,yieldingofthetensilesteelonthefarsideoftheloadingpointoccurssimultaneouslywiththeattainmentoflimitcompressivestrainof0.0033inconcrete.Balancedfailure界限破壞Underthis20在這種破壞方式下，遠(yuǎn)離軸向力作用點(diǎn)一側(cè)的受拉鋼筋屈服，同時(shí)受壓區(qū)混凝土達(dá)到0.0033的極限壓應(yīng)變。Compressionfailureofthecolumnoccurswhen(a)therelativeeccentricityissmall,or(b)althoughtherelativeeccentricityislarge,butthetensionreinforcementratioislarge.

在這種破壞方式下，遠(yuǎn)離軸向力作用點(diǎn)一側(cè)的受拉鋼筋屈服，同時(shí)受21當(dāng)相對(duì)偏心距e0/h0較小時(shí)，或盡管相對(duì)偏心距e0/h0較大，但受拉鋼筋配置較多時(shí)，柱子會(huì)發(fā)生受壓破壞。Columnsofthistypefailbycrushingoftheconcreteandcompressiveyieldingofthesteelonthesideneartheload,whilethereinforcementonthesidefarthestfromtheloaddoesnotyield.當(dāng)相對(duì)偏心距e0/h0較小時(shí)，或盡管相對(duì)偏心距e0/h0較大22這種破壞表現(xiàn)為離荷載作用點(diǎn)近的一側(cè)混凝土壓碎鋼筋受壓屈服，而另一側(cè)鋼筋沒有屈服，如圖4.29b所示。這種破壞表現(xiàn)為離荷載作用點(diǎn)近的一側(cè)混凝土壓碎鋼筋受壓屈服，而23Capacityofshortcolumnsundercombinedaxialforceandmoment短柱抵抗彎壓共同作用的能力Thestrengthinteractiondiagramdefinesthefailureloadandfailuremomentforagivencolumnforthefullrangesofeccentricityfromzerotoinfinity.Capacityofshortcolumnsund24強(qiáng)度相關(guān)圖給出了某一柱子偏心距從零到無(wú)窮大時(shí)的破壞荷載與彎距。0.00330.00330.0033e=0e0smalle0large強(qiáng)度相關(guān)圖給出了某一柱子偏心距從零到無(wú)窮大時(shí)的破壞荷載與彎距25Theextremeconcretefiberstrainreachesultimatestrain(0.003)simultaneouslywithyieldingoftheextremelayerofsteelontheoppositeside(fy/Es=0.002).混凝土的最大應(yīng)變達(dá)到極限應(yīng)變（0.0033），另一側(cè)的最外層鋼筋同時(shí)達(dá)到屈服應(yīng)變（fy/Es=0.002）。Theextremeconcretefiberstr26TheinteractiondiagramfurtherrevealsthatastheaxialforceNubecomeslargerthesectioncancarrysmallerMubeforefailinginthecompressionzone.相關(guān)曲線進(jìn)一步顯示，在受壓破壞區(qū)，構(gòu)件破壞前，隨著軸力增大，截面所承受的彎距越來(lái)越小。Theinteractiondiagramfurthe27Thelargeaxialforceproduceshighcompressivestrainofconcretekeepingsmallermarginavailableforadditionalcompressivestrainduetobending.軸力大，混凝土產(chǎn)生壓應(yīng)變就大，從而無(wú)法承受更多的由彎曲引起的附加壓應(yīng)變。Thelargeaxialforceproduces28Thistensileyieldstressreduceswiththeadditionalcompressivestressduetoadditionalaxialload.隨著附加軸力引起附加的壓應(yīng)力增大，這種受拉鋼筋拉應(yīng)力降低。Thistensileyieldstressredu29Justasforsimplebending,theactualconcretecompressivestressdistributionisreplacedbyanequivalentrectangulardistributionhavingdepthx.僅對(duì)單純的受彎而言,采用受壓區(qū)截面高度為x的等效矩形應(yīng)力分布圖替代實(shí)際混凝土壓應(yīng)力分布。Justasforsimplebending,th30e0e0Actualandequivalentrectangularstressdistributionofeccentricallyloadedcolumnatultimatestrengthe0e0Actualandequivalentrect31另外，混凝土壓應(yīng)力、鋼筋作用力以及外力N關(guān)于受拉鋼筋合力中心線的彎距和必須等于0。Inaddition,sumofthemomentsoftheconcretecompressivestress,reinforcementforceandtheexternalforceNaboutthecenterlineoftheresultantforceinthetensionreinforcementmustequalzero另外，混凝土壓應(yīng)力、鋼筋作用力以及外力N關(guān)于受拉鋼筋合力中心32Additionaleccentricity附加偏心距SlenderColumns長(zhǎng)柱Ontheotherhand,theslenderorlongcolumnsmayfailatamuchlowervalueoftheloadwhensuddenlateraldisplacementofthemembertakesplacebetweentheends.Additionaleccentricity附加偏心距Sl33另一方面，當(dāng)構(gòu)件在兩支承端之間突然發(fā)生橫向側(cè)移，長(zhǎng)柱會(huì)在非常低的荷載作用下破壞。CapacityofAxiallyLoadedSlenderColumn軸心受壓長(zhǎng)柱承載力stabilityreductioncoefficient穩(wěn)定系數(shù)另一方面，當(dāng)構(gòu)件在兩支承端之間突然發(fā)生橫向側(cè)移，長(zhǎng)柱會(huì)在非常34Thelowerratiolimitisnecessarytoensureresistancetobendingmomentnotaccountedintheanalysisandtoreducetheeffectsofcreepandshrinkageoftheconcreteundersustainedcompression.為了確保抵抗分析中沒有考慮的彎矩以及減少混凝土在持續(xù)荷載壓力作用下混凝土徐變和收縮的影響，必須設(shè)置配筋下限。Thelowerratiolimitisneces35Spacingbetweenlongitudinalbarsmeasuredalongthecentroidshouldnotexceed300mm.縱筋凈間距不超過300mm。

Whenthedepthoftheeccentricallyloadedcolumnisgreaterthan600mm,additionallongitudinalbarswithadiameterof10~16mmshouldbeplacedonthelateralsides.

Spacingbetweenlongitudinalb36當(dāng)偏心受壓柱的截面高度大于600mm時(shí)，沿兩側(cè)向應(yīng)該各增加一根直徑10-16的附加縱筋。

當(dāng)偏心受壓柱的截面高度大于600mm時(shí)，沿兩側(cè)向應(yīng)該各增加一37Thetiesshallbesoarrangedthateverycornerandalternatelongitudinalbarshallhavelateralsupportprovidedbythecornerofatiehavinganincludedangleofnotmorethan,andnolongitudinalbarshallbefartherthan300mmoneithersidefromsuchalaterallysupportedbar.Thetiesshallbesoarranged38箍筋應(yīng)該如此布置，柱的每個(gè)角以及每隔一根縱筋都應(yīng)該有由箍筋的角提供的側(cè)向支撐，箍筋?yuàn)A角不超過135o，縱向鋼筋的任何一側(cè)離具有這樣的側(cè)向支撐鋼筋的凈間距不應(yīng)超過300mm。箍筋應(yīng)該如此布置，柱的每個(gè)角以及每隔一根縱筋都應(yīng)該有由箍筋的39Cross-sectionsinbuildingsCross-sectionsinbuildings40

Inaddition,aminimumratioofspiralsteelisimposedsuchthatthestructuralperformanceofthecolumnissignificantlyimproved,withrespecttobothultimateloadandthetypeoffailure,comparedwithanotherwiseidenticaltiedcolumn.Inaddition,aminimumratio41另外，采用配筋比較小的螺旋箍筋有利于改善柱子的性能。與同樣配箍率的箍筋柱相比，其極限荷載有了極大的提高，其破壞型式有所改善。另外，采用配筋比較小的螺旋箍筋有利于改善柱子的性能。與同樣配42Whilespiralsarenotrequiredtorunthroughthecolumn-to-floorconnectionzones,tiesshouldbeinsertedinthosezonestomaintainproperconfinement,especiallyifhorizontalbeamsdonotframeintothesezones.Whilespiralsarenotrequire43對(duì)于不需要貫穿柱-板聯(lián)結(jié)區(qū)的螺旋箍而言，尤其是水平梁不與柱固結(jié)時(shí)，應(yīng)將箍筋插入這些區(qū)域，保持對(duì)縱筋的適當(dāng)約束。對(duì)于不需要貫穿柱-板聯(lián)結(jié)區(qū)的螺旋箍而言，尤其是水平梁不與柱固44

結(jié)束語(yǔ)謝謝大家聆聽?。?！45

結(jié)束語(yǔ)謝謝大家聆聽?。?！4544鋼筋混凝土柱44鋼筋混凝土柱AxialCompression軸向受壓承受壓力的構(gòu)件被稱作柱子Columnsaredefinedasmembersthatcarryloadschieflyincompression.AxialCompression軸向受壓承受壓力的構(gòu)件被47最新44鋼筋混凝土柱課件48最新44鋼筋混凝土柱課件49最新44鋼筋混凝土柱課件50最新44鋼筋混凝土柱課件51最新44鋼筋混凝土柱課件52最新44鋼筋混凝土柱課件53Forthispurpose,longitudinalandtransversesteeliswiredtogethertoformcages,whicharethenmovedintotheformsandproperlypositionedbeforeplacingtheconcrete.因此，將縱向鋼筋和箍筋綁扎在一起，形成鋼筋骨架，然后將其移入模板中，在澆筑混凝土前正確擺放。Forthispurpose,longitudinal54Foranother,transversereinforcementisneededtopreventthehighlystressed,slenderlongitudinalbarsfrombucklingoutwardbyburstingthethinconcretecover.另外，箍筋能夠防止應(yīng)力較大的、細(xì)長(zhǎng)縱筋向外彎曲，崩裂單薄的混凝土保護(hù)層。Foranother,transversereinfo55BehaviorofAxiallyLoadedShortColumn軸心受壓短柱的特性Whenanaxialloadisappliedtoareinforcedconcreteshortcolumn,theconcretecanbeconsideredtobehaveelasticallyuptoalowstressofabout(1/3).

BehaviorofAxiallyLoadedSho56當(dāng)荷載作用在鋼筋混凝土短柱形心時(shí)，應(yīng)力低于,混凝土被認(rèn)為具有彈性特性。

Atthisloadtheconcretefailsbycrushingorshearingoutwardalonginclinedplanes,andthelongitudinalsteelbarsfailbybucklingoutwardbetweenties,asshowninFigure4.26(a).當(dāng)荷載作用在鋼筋混凝土短柱形心時(shí)，應(yīng)力低于,混凝土被認(rèn)為具有57普通箍筋柱在荷載Na作用下破壞。在此荷載下，由于混凝土壓碎或向外沿斜面受剪破壞，縱筋由于在箍筋之間向外彎曲而破壞，如圖（4.26a）所示。普通箍筋柱在荷載Na作用下破壞。在此荷載下，由于混凝土壓碎或58Itisatthisstagethattheconfiningactionofthespiralhasasignificanteffect,andifsizablespiralsteelisprovided,theloadwillultimatelyfailthecolumnbycausingthespiralsteeltoyield.正是在這個(gè)階段，螺旋箍發(fā)揮著重要的約束作用。如果配置大量的螺旋箍，當(dāng)荷載使螺旋筋屈服時(shí)，柱子發(fā)生破壞。Itisatthisstagethatthe59BothtiedandspirallyreinforcedcolumnsbehavesimilarlyTiedcolumnfailssuddenlyYieldpoint(Spirallyreinforcedconcreteshellspallsoff)SpirallyreinforcedcolumnshowsabilitytodeformpriortofailureDeformationNaloadBothtiedandspirallyreinfo60(a)Unsupportedbarsbuckle(b)ConcreteshellspallsoffFailureoftiedandspirallyreinforcedconcretecolumn(a)Unsupportedbarsbuckle61ShortColumnsunderCombinedAxialForceandMoment軸力及彎矩共同作用下的短柱

ShortColumnsunderCombinedA62WhenamemberissubjectedtocombinedaxialcompressionNandmomentM,suchasinFigure4.28(a),itisusuallyconvenienttoreplacetheaxialloadandmomentwithanequalloadNappliedateccentricity,asinFigure4.28(b).

Whenamemberissubjectedto63當(dāng)柱子承受軸力N以及彎距M的共同作用時(shí)，如圖4.28a，通常用軸力N作用在距離軸心e=M/N處取代構(gòu)件承受的軸力和彎矩，如圖4.28b所示，是一種很簡(jiǎn)便的方法。NNeM當(dāng)柱子承受軸力N以及彎距M的共同作用時(shí)，如圖4.28a，通常64Balancedfailure界限破壞Underthismodeoffailure,yieldingofthetensilesteelonthefarsideoftheloadingpointoccurssimultaneouslywiththeattainmentoflimitcompressivestrainof0.0033inconcrete.Balancedfailure界限破壞Underthis65在這種破壞方式下，遠(yuǎn)離軸向力作用點(diǎn)一側(cè)的受拉鋼筋屈服，同時(shí)受壓區(qū)混凝土達(dá)到0.0033的極限壓應(yīng)變。Compressionfailureofthecolumnoccurswhen(a)therelativeeccentricityissmall,or(b)althoughtherelativeeccentricityislarge,butthetensionreinforcementratioislarge.

在這種破壞方式下，遠(yuǎn)離軸向力作用點(diǎn)一側(cè)的受拉鋼筋屈服，同時(shí)受66當(dāng)相對(duì)偏心距e0/h0較小時(shí)，或盡管相對(duì)偏心距e0/h0較大，但受拉鋼筋配置較多時(shí)，柱子會(huì)發(fā)生受壓破壞。Columnsofthistypefailbycrushingoftheconcreteandcompressiveyieldingofthesteelonthesideneartheload,whilethereinforcementonthesidefarthestfromtheloaddoesnotyield.當(dāng)相對(duì)偏心距e0/h0較小時(shí)，或盡管相對(duì)偏心距e0/h0較大67這種破壞表現(xiàn)為離荷載作用點(diǎn)近的一側(cè)混凝土壓碎鋼筋受壓屈服，而另一側(cè)鋼筋沒有屈服，如圖4.29b所示。這種破壞表現(xiàn)為離荷載作用點(diǎn)近的一側(cè)混凝土壓碎鋼筋受壓屈服，而68Capacityofshortcolumnsundercombinedaxialforceandmoment短柱抵抗彎壓共同作用的能力Thestrengthinteractiondiagramdefinesthefailureloadandfailuremomentforagivencolumnforthefullrangesofeccentricityfromzerotoinfinity.Capacityofshortcolumnsund69強(qiáng)度相關(guān)圖給出了某一柱子偏心距從零到無(wú)窮大時(shí)的破壞荷載與彎距。0.00330.00330.0033e=0e0smalle0large強(qiáng)度相關(guān)圖給出了某一柱子偏心距從零到無(wú)窮大時(shí)的破壞荷載與彎距70Theextremeconcretefiberstrainreachesultimatestrain(0.003)simultaneouslywithyieldingoftheextremelayerofsteelontheoppositeside(fy/Es=0.002).混凝土的最大應(yīng)變達(dá)到極限應(yīng)變（0.0033），另一側(cè)的最外層鋼筋同時(shí)達(dá)到屈服應(yīng)變（fy/Es=0.002）。Theextremeconcretefiberstr71TheinteractiondiagramfurtherrevealsthatastheaxialforceNubecomeslargerthesectioncancarrysmallerMubeforefailinginthecompressionzone.相關(guān)曲線進(jìn)一步顯示，在受壓破壞區(qū)，構(gòu)件破壞前，隨著軸力增大，截面所承受的彎距越來(lái)越小。Theinteractiondiagramfurthe72Thelargeaxialforceproduceshighcompressivestrainofconcretekeepingsmallermarginavailableforadditionalcompressivestrainduetobending.軸力大，混凝土產(chǎn)生壓應(yīng)變就大，從而無(wú)法承受更多的由彎曲引起的附加壓應(yīng)變。Thelargeaxialforceproduces73Thistensileyieldstressreduceswiththeadditionalcompressivestressduetoadditionalaxialload.隨著附加軸力引起附加的壓應(yīng)力增大，這種受拉鋼筋拉應(yīng)力降低。Thistensileyieldstressredu74Justasforsimplebending,theactualconcretecompressivestressdistributionisreplacedbyanequivalentrectangulardistributionhavingdepthx.僅對(duì)單純的受彎而言,采用受壓區(qū)截面高度為x的等效矩形應(yīng)力分布圖替代實(shí)際混凝土壓應(yīng)力分布。Justasforsimplebending,th75e0e0Actualandequivalentrectangularstressdistributionofeccentricallyloadedcolumnatultimatestrengthe0e0Actualandequivalentrect76另外，混凝土壓應(yīng)力、鋼筋作用力以及外力N關(guān)于受拉鋼筋合力中心線的彎距和必須等于0。Inaddition,sumofthemomentsoftheconcretecompressivestress,reinforcementforceandtheexternalforceNaboutthecenterlineoftheresultantforceinthetensionreinforcementmustequalzero另外，混凝土壓應(yīng)力、鋼筋作用力以及外力N關(guān)于受拉鋼筋合力中心77Additionaleccentricity附加偏心距SlenderColumns長(zhǎng)柱Ontheotherhand,theslenderorlongcolumnsmayfailatamuchlowervalueoftheloadwhensuddenlateraldisplacementofthemembertakesplacebetweentheends.Additionaleccentricity附加偏心距Sl78另一方面，當(dāng)構(gòu)件在兩支承端之間突然發(fā)生橫向側(cè)移，長(zhǎng)柱會(huì)在非常低的荷載作用下破壞。CapacityofAxiallyLoadedSlenderColumn軸心受壓長(zhǎng)柱承載力stabilityreductioncoefficient穩(wěn)定系數(shù)另一方面，當(dāng)構(gòu)件在兩支承端之間突然發(fā)生橫向側(cè)移，長(zhǎng)柱會(huì)在非常79Thelowerratiolimitisnecessarytoensureresistancetobendingmomentnotaccountedintheanalysisandtoreducetheeffectsofcreepandshrinkageoftheconcreteundersustainedcompression.為了確保抵抗分析中沒有考慮的彎矩以及減少混凝土在持續(xù)荷載壓力作用下混凝土徐變和收縮的影響，必須設(shè)置配筋下限。Thelowerratiolimitisneces80Spacingbetweenlongitudinalbarsmeasuredalongthecentroidshouldnotexceed300mm.縱筋凈間距不超過300