11.设计资料南京的某厂房采用单跨双坡门式刚架。长度90m,柱距6m,跨度15m。门式刚架檐高6m,屋面坡度为1:10。刚架为变截面梁、柱,柱脚铰接。钢材选用Q345钢,焊条采用E43型。基础混凝土C25。屋面材料:夹芯板0.25kN/㎡。墙面材料:夹芯板0.25kN/㎡。天沟:钢板天沟。自然条件:基本雪压0.65kN/㎡基本风压0.4kN/㎡不考虑地震作用,屋面无积灰,厂房无吊车。恒载0.25kN/㎡活载0.5kN/㎡经过验算可以选择檩条为C160×60×20×3.0水平间距1.5m2.梁柱界面选择及截面特性截面简图截面特性1-1剖面22-2(3-3)剖面4-4剖面5-5剖面3.荷载计算(1)荷载取值计算屋面自重(标准值,沿坡向):夹芯板0.25kN/㎡檩条及支撑0.15kN/㎡刚架横梁0.10kN/㎡总计0.50kN/㎡屋面雪荷载(标准值)0.65kN/㎡3屋面均布活荷载(标准值)0.50kN/㎡柱及墙梁自重(标准值)0.55kN/㎡风载基本风压w0=0.4kN/㎡,地面粗糙度为B类,按封闭建筑选取中间区单元,刚架风载体型系数如下:(2)分项荷载作用计算1)屋面永久荷载作用标准值为0.5×αcos1×6=3.01kN/㎡2)屋面可变荷载作用标准值为0.65×αcos1×6=3.92kN/㎡3)柱及墙梁自重标准值为0.55×6=3.3kN/㎡4)风载墙面风荷载变化系数按柱顶标高计算取为1.0,则W=1.0×0.4=0.4kN/㎡墙面风雅标准值为qwAB=0.4×(+0.25)×6=+0.6kN/㎡qwDE=0.4×(-0.55)×6=-1.32kN/㎡屋面负风压标准值为qwBC=0.4×(-1.00)×6=-2.4kN/㎡4qwCD=0.4×(-0.65)×6=-1.56kN/㎡4.刚架内力计算及组合(1)刚架内力计算《按建筑结构静力计算手册》中的变截面刚架进行计算已知斜梁长度a=7.537m,矢高f=0.75m,柱高h=6.0m,跨度l=15mØ=II023012×ha=6.261323.15667×6537.7=0.7534Ψ=hf=0.675.0=0.125对于横梁23有V=llh=5.73=0.4t=(ddmaxmin)3=(776376)3=0.114lm=1对于柱12有V=1t=(822272)3=0.036查表可以得到α23=3.888α32=1.804β23=1.617α21=0.307θ23=α23+α32+2β23=8.926A=θ23+Ψ²α32+2Ψ(α32+β23)+Φα21=10.217B=α32(1+Ψ)+β23=3.6465C=α23+β23(1+Ψ)+Φα21=6.115Rw2323=0.459Rw32=0.349Rw21=0.309Kww2323=Rw2323+Rw32(1+Ψ)=0.8525N=B+C+Φw212R=10.582故计算出内力图如下屋面恒载作用下屋面活载作用下风荷载作用下6(2)刚加内力组合刚架梁内力组合表钢架柱内力组合表(3)最不利荷载组合作用下刚架M、N、V图如下75.刚架梁柱截面验算(1)构件宽厚比验算1)梁翼缘tb=122)8-250(=10.0815fy235=15345235=12.038(满足要求)2)柱翼缘tb=142)8-250(=8.6415fy235=15345235=12.038(满足要求)3)梁腹板对1—1截面thww=8776=97250fy235=206.33(满足要求)对2—2、3--3截面thww=8376=47250fy235=206.33(满足要求)4)柱腹板对柱底5--5截面thww=8272=34250fy235=206.33(满足要求)对柱顶4—4截面thww=8822=102.75250fy235=206.33(满足要求)(2)有效截面特性1)柱有效截面特性翼缘柱受压翼缘为一边支承、一边自由的均匀受压板件,当其自由外伸宽厚比不超过规范所规定的允许宽厚比时,柱受压翼缘全截面有效。因此σ1=AN+WMnxxxγ=374930005.1034.1341357625.68101063××+×=39.074N/mm2由α=(σ1-σ2)/σ1=0查得ζ=5N/mm2则tb=142)8-250(=8.64[tb]=100σξ1=100074.395=35.772(满足要求)8腹板柱腹板为两边支承非均匀受压板件,其有效宽度按规范计算。柱顶4—4截面腹板最大、最小应力为=σσ21±ANIxxyM=1010104637.159345411034.1341357625.68×××±×=544.29-598.39N/mm2腹板受压区高度为hc=544.29598.39598.39+×822=470.764㎜σ1=39.598N/mm2f=310N/mm2故取fy=γRσ1=1.1×39.598=43.558N/mm2β==σσ21-0.746kσ=)1(2216])-1(112.0)1([5.0βββ++++=17.954λp=2351.28fkthywwσ=235558.43954.171.288822××=0.3720.8故取ρ=1.0,即腹板全截面有效对柱底5—5截面σ1=ANn=917601.92103×=10.027N/mm2f=310N/mm2故取fy=γRσ1=1.1×10.027=11.03N/mm2β==σσ211.0则kσ=)1(2216])-1(112.0)1([5.0βββ++++=4λp=2351.28fkthywwσ=23503.1141.288272××=0.1310.8故取ρ=1.0,即腹板全截面有效2)梁有效截面特性翼缘粱受压翼缘为一边支承、一边自由的均匀受压板件,当其自由外伸宽厚比不超过规范所规定的允许宽厚比时,柱受压翼缘全截面有效。因此对1—1截面9σ1=AN+WMnxxxγ=310750005.1034.1341220828.29101063××+×=43.477N/mm2tb=122)8-250(=10.08[tb]=100σξ1=100477.435=33.912(满足要求)对2--2截面σ1=AN+WMnxxxγ=130663005.1249.349008549.26101063××+×=27.911N/mm2tb=122)8-250(=10.08[tb]=100σξ1=100911.275=42.325(满足要求)同理3—3截面满足要求。腹板柱腹板为两边支承非均匀受压板件,其有效宽度按规范计算。对1—1截面腹板最大、最小应力为=σσ21±ANIxxyM=1010104634.124301388034.1341220828.29×××±×=39.44-236.44N/mm2腹板受压区高度为hc=44.39236.44236.44+×776=410.239㎜σ1=44.236N/mm2f=310N/mm2故取fy=γRσ1=1.1×44.236=48.66N/mm2β==σσ21-0.892kσ=)1(2216])-1(112.0)1([5.0βββ++++=21.324λp=2351.28fkthywwσ=23566.48324.211.288776××=0.340.8故取ρ=1.0,即腹板全截面有效对3--3截面腹板最大、最小应力为=σσ21±ANIxxyM=1010104636.26132188034.1349008091.22×××±×=73.194-098.78N/mm2腹板受压区高度为hc=194.73098.78098.78+×376=194.094㎜10σ1=78.098N/mm2f=310N/mm2故取fy=γRσ1=1.1×478.098=85.908N/mm2β==σσ21-0.937kσ=)1(2216])-1(112.0)1([5.0βββ++++=222.4λp=2351.28fkthywwσ=235908.854.221.288376××=0.2140.8故取ρ=1.0,即腹板全截面有效(3)刚架梁的验算1)抗剪承载力验算梁截面的最大应力为Vmax=65.692kN,考虑只有支座加劲肋,取kτ=5.34,则34523534.5378/77623537××==fkthywwτωλ=1.3750.8且1.4'fv=[1-0.64(λw-0.8)]fv=[1-0.64(1.375-0.8)]×180=113.76kN/mm2Vd=hwtw'fv=776×8×113.76=706.222kNVmaxVd(满足要求)2)弯剪压共同作用下的强度验算对1—1截面M=134.034kN.mN=29.28kNV=65.692kNMe=fwe=3107.5310103××=963.325kN.m由V0.5Vd,可得==AMMeeNe/N-We872.95512208/3107.529.28-325.963101066=×××kN.mM=134.034kN.m对2--2截面M=34.249kN.mN=26.549kNV=24.945kNMe=fwe=1306.63310103××=405kN.m11由V0.5Vd,可得==AMMeeNe/N-We149.4019008/1306.6326.549-405101066=×××kN.mM=34.249kN.m对3--3截面M=105.15kN.mN=22.091kNV=2.223kNMe=fwe=1306.63310103××=405kN.m由V0.5Vd,可得==AMMeeNe/N-We796.4019008/1306.6322.091-405101066=×××kN.mM=105.15kN.m3)平面外的整体稳定验算斜梁不需计算整体稳定性的侧向支承点间最大长度,可取斜梁受压翼缘宽度的16fy235倍,隅撑的间距为3000mm,满足上述要求,刚架斜梁不需要计算整体稳定性。(4)刚架柱的验算1)抗剪承载力验算柱截面的最大应力为Vmax=22.339kN,考虑只有支座加劲肋,取kτ=5.34,则34523534.5378/27223537τωλ××==fkthyww=0.4820.8'fv=fv=180kN/mm2Vd=hwtw'fv=272×8×180=391.68kNVmaxVd(满足要求)2)弯剪压共同作用下的强度验算由V0.5Vd,可得==AMMeeNe/N-We434.114313576/3749.368.25-3103.3749101010336=×××××kN.mM=134.034kN.m3)平面内整体稳定验算12柱的计算长度hrlμ=0,hIkEcr314.4=μE=206103×,cmIc403.15667=,cmIc417.159345=,cmIb406.26132=,h=(6000-200)mm=5800mms=7.537mψ=0.5故Ic0/Ic1=0.098K1=Ic1/h=274.734,K2=Ib0/(2ψs)=34.672K1/K2=7.924则查表可得μr=0.752hrlμ=0=0.752×6000=4512mmλ=ilx0=1.134512=34.443查表得Ψxγ=0.92取βmx=1.0kNEANeEx142801.191762061.134.4431010π'2-3322020=×××××==λπfkNmmwMANemxeX=××××××+××=+234631Ex00100/86.463.3749)92.01.42892.01-1(034.1340.1917692.001.92)-1(10101010N'Nψβψγγ(满足要求)4)平面外整体稳定性验算楔率:6.02.0221.0-27.282.21.0-21===ddγAf=2×25×1.4=70㎝2iy0=cm87.625.779.3646=502.1702.27300022.2023.01023.010=×××+=+=Ahufslγ59.6587.6300502.100=×==