附加约束矩形钢管高强混凝土柱的材料本构模型、方钢管高强混凝土柱耐火极限和保护层设计厚度.docx

附录A附加约束矩形钢管高强混凝土柱的材料本构模型A.1内配螺旋箍筋矩形钢管高强混凝土柱中混凝土等效单轴受压应力-应变曲线按下列公式确定:,(4/%)T+(a%)匕(/%)+(W-1)(4/%)2l+0-2)(q%)+W(q%)2k-JEcYfe/%)Ec=332OZ7+69OO久%(A.1-1)4>为(A.1-2)(A.1-3)(A.1-4)(A.1-5)(A.1-6)(A.1-7)%=0.0005瑞K=-3.157-0.27W=8.032+1.33esPsfupo鼠=：一4、(A.1-8)2(°-p)(A.1-9)Ds式中：螺旋箍筋约束指标；为一无约束混凝土的轴心抗压强度；o无约束混凝土的峰值压应变；螺旋箍筋的抗拉强度；D螺旋箍筋约束区直径；&P螺旋箍筋直径；S螺旋箍筋间距；Asp螺旋箍筋的截面面积；匕、W控制承载力下降速率、残余强度的指标。A.2外包套管矩形钢管高强混凝土柱中混凝土等效单轴受压应力-应变曲线按下列公式确定:,%/%)cc/T+(4/%)：匕(4/%)+(卬-1)(纭/1)21+(匕-2)(纭/%)+伙久/%)2k=2凡-(几/%)纥=3320匹;+6900%=0.0005窗&=3.2484+1oj睦=2.456+1,匕=-9.6642+0.035W=II.54考52+o.99(A.2-1)(A.2-2)(A.2-3)(A.2-4)(A.2-5)(A.2-6)(A.2-7)(A.2-8)(A.2-9)(A.2-10)42佃一245(26一4一4一2犷Q43(-2r)2式中：5一混凝土的应力;混凝土的应变;%套管约束指标;fj-套管厚度；力套管截面宽度;fyi套管屈服强度。图A.2套管有效约束区示意图A.3带约束拉杆矩形钢管高强混凝土柱中混凝土等效单轴受压应力-应变曲线按下列公式确定:f/%)I+(1/%)J匕(/1)+3-1)(/%)2cl+(K-2)(%)+W(久/%(久()(纭>%)k-_J%)纥=3320兀+6900X0(1+W0-7)%=¾>(1+35%L2)WSZ-l)4"AbSv修_2"%=0.0005窗K=6.57-0.08W=8.5/+0.93式中：c混凝土的应力；&混凝土的应变；fee约束混凝土轴心抗压强度；约束混凝土峰值压应变；EC混凝土的弹性模量；启无约束混凝土的轴心抗压强度；&0无约束混凝土的峰值压应变；2混凝土的有效约束指数；约束拉杆对核心混凝土的等效约束应力；Sh、SV约束拉杆的水平、竖向间距；b钢管截面宽度；I钢管厚度；fy钢管的屈服强度Atb约束拉杆的抗拉强度设计值，当力,tb大于400MPa时,Atb约束拉杆的横截面面积；(A.3-1)(A.3-2)(A.3-3)(A.3-4)(A.3-5)(A.3-6)(A.3-7)(A.3-8)(A.3-9)(A.3-10)Ib=400MPaVeW控制承载力下降速率、残余强度的指标。截面B-B截面A-A图A.3拉杆有效约束区示意图附录B方钢管高强混凝土柱耐火极限和保护层设计厚度8.1 无防火保护方钢管高强混凝土柱耐火极限可按表X取值。表B.1标准火灾作用下方钢管超高强混凝土柱耐火极限min)长细比截面边长mm)荷载比0.3荷载比0.4荷载比0.5荷载比0.6荷载比0.7104004531221576005437271710800654332211210007349352414120082544026161400925948291816009965493121180010971533624200011775564225204004129201176005036251788006042322012100068463424141200765137231414008357402817160090614429191800976447322120001037151372230400362217966004835251388005339301691000644433181112007147362013140073534027141600796041291718008762412919200090664230194040036211586600433320127800563925149100059433218111200654636191314006852392114160078584622161800836239271720009470533619续表B.1长细比截面边长mm)荷载比0.3荷载比0.4荷载比0.5荷载比0.6荷载比0.75040022191476600372915107800433417129100050402316111200574325171214006149282013160069533621141800745736261620008061373118604001411865600191411868002118131071000282319141012003127211612140035302519151600393428211418004037322316200044404023188.2 采用非膨胀型防火涂料时，方钢管超高强混凝土柱防火涂料设计厚度可按表B.2或表B.3取值。表B.2耐火极限为2.5h时非膨胀型防火涂料设计厚度min)长细比截面边长mm)荷载比0.3荷载比0.4荷载比0.5荷载比0.6荷载比0.710400101218286360010101525458001()1012213810001()1()1118341200101()10173014001()101()162816001()10101524180010101()13212000101()1011212040010132039636001()101625578001()1()12223810001010121834120010101120351400101010162916001010101627续表B.2长细比截面边长mm)荷载比0.3荷载比0.4荷载比0.5荷载比0.6荷载比0.720180010101015252000101010132430400101824487360010111634578001010132852100010101226441200101011243814001010101737160010101016301800101011172820001010111729404001019285473600101121376580010101732521000101013264412001010112538140010101123371600101010233318001010111832200010101013295040018213063736001013294565800101126385210001010192944120010101828421400101016244016001010122438180010101319342000101013163160400303954738960022314057778002124354768100015192434491200141622304214001215192634160011131724381800111215223420001011112331表B.3耐火极限为3h时非膨胀型防火涂料设计厚度min)长细比截面边长mm)荷载比0.3荷载比0.4荷载比0.5荷载比0.6荷载比0.7104001015223476600101218315480010111525471000101014234112001010132137140010101020341600101010193018001010101626200010101014262040010162447766001013203169800101115274710001010152341120010101425431400101013203616001010122033180010101119312000101011163030400122229588960010132041698001012173463100010111631531200101014294614001010132145160010101320371800101014213420001010142135404001223346689600101426457980010122140631000101116315312001011143146140010101428451600101011284018001010152339200010101017355040022263676896001217355479800111432476310001012243653续表B.3长细比截面边长mm)荷载比0.3荷载比0.4荷载比0.5荷载比0.6荷载比0.7501200101222355114001010203048160010101630461800101016244120001010162038604003647668910760027384969938002530435783100019242941591200172127375114001619233241160014172130461800141619284120001315152938注：表B.2、表B.3中非膨胀型防火涂料厚度是根据涂料等效热传导系数为0.116W(m°C)计算得到的，当实际工程选用的防火涂料等效热传导系数与上述数值不同时，应基于防火涂料热阻相等的原则确定其所需的厚度。【说明】B.1通过热-力耦合有限元分析计算得到了标准火灾下方钢管超高强混凝土柱的耐火极限，需要说明的是：1计算采用的升温曲线为国家标准建筑构件耐火试验方法第1部分：通用要求GB/T9978.1中规定的升温曲线，也是国际标准ISO834推荐的标准升温曲线。2高温下C60C120混凝土的轴心抗压强度折减系数和应力-应变关系参考了欧洲规范EN1992-1-2:2004的有关规定。普通强度结构钢人S460Nmm2)采用了欧洲规范EN1993-1-2:2005建议的本构关系；高强度结构钢的屈服强度折减系数和弹性模量折减系数，参考文献“王卫永，张艳红，李国强.高强钢高温下和高温后力学性能指标的标准值研究.建筑结构学报，2022,43(09):138-150”建议的公式。3在相同尺寸和荷载比下，采用普通结构钢的钢管混凝土柱抗火性能要优于高强钢管高强混凝土柱。混凝土抗压强度的提高在一定范围内会延长柱构件的耐火极限，但也会导致高温下混凝土强度损伤增大。经计算发现，钢材牌号Q690、混凝土等级C105时为钢管混凝土柱构件抗火性能最不利情况，出于安全考虑表B.1取该强度组合下柱构件的耐火极限。4表格B.1涵盖的直径、荷载比和长细比考虑了钢管混凝土实际工程应用的常见范围。含钢率对钢管混凝土耐火极限影响较小，计算时按照工程常用值取为10%«B.2基于表B.1无防火保护方钢管超高强混凝土柱耐火极限计算得到了不同耐火等级所需要的非膨胀型防火涂料厚度：1计算时非膨胀型钢结构防火涂料等效热传导系数取0.116W(m°C)o2在计算表B.2和表B.3中非膨胀型防火涂料厚度时参考了钢管混凝土结构技术规范GB50936中防火涂料厚度的计算公式，并针对方钢管超高强混凝土柱进行了修正:d=(0.006D+24)h(生-1)(X.1-1)晨式中：d混凝土的应力；D方钢管混凝土柱边长mm)；然防火涂料导热系数W(m°C);te设计耐火极限min)；Ae无保护层时构件的耐火极限min),可由表B.1取。3考虑非膨胀型防火涂料施工最小厚度的需要，参考建筑钢结构防火技术规范GB51249,若计算厚度小于IOmm则统一取为IOmmo