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DesignofthePRCSSBName:何书进Number:201421080218Class:20142108022Catalogue1.Thedataofdesign................................................................................32.Mainbeamsize.....................................................................................33.Geometricfeaturesofallcrosssection.................................................44.Themainbeaminnerforceofcalculation.............................................55..Estimationofreinforcementareaandlayoutsteelcable.....................56.Calculationofgeometricfeaturesofmainbeamcross-section.............97.Calculationofcarryingcapacityultimatelimitstate...........................108.Estimationofpre-stresslosses............................................................129.Stresscheck........................................................................................1610.Checkofcracking..............................................................................1811.Deformationcalculate......................................................................1912.Thelayoutofpre-archvalue.............................................................211.Thedataofdesign3(1)SpanofSSB:28.18m,computedspanL=26.84m(2)Designload:vehicularload-Ι,pedestrianloadis3.0kN/m2,coefficientofimportanceγ0=1.0(3)Environment:Bridgelocatesinacommonfield,environmentclass-Ι,relativehumidity(averageofperyear)is75%.(4)Materials:Tendon:lowslackstrands(1×7):standardvalueoftensionstrength𝑓𝑝𝑘=1860𝑀𝑃𝑎,Designvalueoftensionstrength𝑓𝑝𝑑=1260𝑀𝑃𝑎,nominalarea=140mm2,nominaldiameteris15.2mm,elasticmodulus𝐸𝑝=1.95×105𝑀𝑝𝑎,strandtaperedofgroupanchors.Nonprestressedreinforcement:HRB400,𝑓𝑠𝑘=100𝑀𝑃𝑎,𝑓𝑠𝑑=330𝑀𝑃𝑎;HRB335:d12mm,normalvalueoftensionstrength𝑓𝑠𝑘=335𝑀𝑃𝑎,designvalueoftensionstrength𝑓𝑠𝑑=280𝑀𝑃𝑎,;elasticmodulus𝐸𝑠=2.0×105𝑀𝑃𝑎;concreteC50:𝐸𝑐=2.45×104MPa;normalvalueofcompressstrength𝑓𝑐𝑘=32.4𝑀𝑃𝑎.Designvalueofcompressstrength𝑓𝑐𝑑=22.4𝑀𝑃𝑎;normalvalueoftensionstrength𝑓𝑡𝑘=2.65𝑀𝑃𝑎;designvalueoftensionstrength𝑓𝑡𝑑=1.83𝑀𝑃𝑎.(5)Designrequirements:JTGD62-2004,totalpre-stressconcrete.(6)Constructionmethod:post-tension:pre-costgirder;TDJack;cast-in-sitewetconnectionjointwithwidthof40m;asphaltlagerwith80mmthickness.2.MainbeamsizeJustlikethepicture.3.Geometricfeaturesofallcrosssection(1)Calculationofeffectivewidthbf’Accordingtothehighwaybridgegauge,theminimumvalueofthefollowthreevaluecanbegot.4①1/3simplesupportedbeamspan,l/3=26850/3=8950mm.②Theaveragedistancebetweentwoadjacentbeams.Tothemiddlebeamsis2200mm.③(b+2𝑏ℎ+12ℎ𝑓′),𝑏ℎ=0,solethfisequivalentwithaverageofwebthicknessaboutmiddlespansectionSo(b+2𝑏ℎ+12ℎ𝑓′)=200+6×0+12×228=2936𝑚𝑚.Aboveall,the𝑏𝑓′=2200𝑚𝑚.(2)Calculatinggeometricfeaturesofallcross-sectionGenerally,geometricfeaturesofmainbeamoftenuseblocknumericalsummationmethod.Areaofallcross-section:A=∑𝐴𝑖Distancebetweengravitycenterlineoftheallcross-sectionandthetopofthebeam:𝑦𝑢=∑𝐴𝑖𝑦𝑖𝐴Ai—theareaofseparatedsection𝑦𝑖—thedistancebetweenthecenterofgrarityofseparatedsectionandedgeofbeamGeometryfeaturesofallcross-sectionforΙ-ΙsectionNumberofblockAreaofblock𝑦𝑖(𝑚𝑚)𝑆𝑖=𝐴𝑖𝑦𝑖(mm)(𝑦𝑢−𝑦𝑖)(𝑚𝑚)𝐼𝑥=𝐴𝑖(𝑦𝑢−𝑦𝑖)2(𝑚𝑚4)𝐼𝑖(𝑚𝑚4)Figureofblocksection①3600009032400×10345474.202×1090.972×109②9600022021120×10332410.078×1090.077×109③320000800256000×103-25620.972×10968.267×109④20000153330660×103-98919.562×1090.044×109⑤800001700136000×103-1156106.907×1090.267×109Summary876000𝑦𝑢=544𝑦𝑏=1256476180×103231.721×10969.627×109I=∑𝐼𝑋+∑𝐼𝑖=301.348×1094.Themainbeaminnerforceofcalculation,causedbypermanentactionandvariableaction.跨中截面L/4截面变化点截面支点截面MmaxVVmaxMMmaxVVmaxMMmaxVmaxVmax5一期标准值①2124.9002124.91593.6141.7141.71593.61051.7201.4283.3二期标准值现浇湿接缝②196.700196.7147.413.213.2147.497.318.626.2桥面与栏杆③458.700458．7344.130.530.5344.122743.561.2人群荷载④61.802.130.942.54.34.634.824.467.7，公路一级汽车荷载标准值（不计冲击系数）⑤1431.860.595.51074.11104.22702701104.2821.3207306.6公路以及汽车荷载标准值（计冲击系数）⑥1550.665.5103.41163.31195.8292.3292.31195.8889.4223.2332.1持久状态的应力计算的可变作用标准值组合⑦1612.565.5105.41194.21238.3296.7296.91230.6913.8230.2339.8承载能力极限状态计算的基本组合⑧5576.591.7147.150004223.9636.6636.94215.32923.8636.8918.4正常使用极限状态按作用短期效应组合计算⑨1064.142.268.9782.8815.4193.3193.6807.7599.3150.9222.3正常使用极限状态按作用长期效用组合计算⑩597.424.239442458.7109.8109.8455.6338.385.2125.75.Estimationofreinforcementareaandlayoutsteelcable.(1)Accordingtotherequirementofresistancecrackfromnormalsectiontoestimatenumberpre-stressedrebar.Fullpre-stressedconcretestructureoftheeffectivepre-stressinmiddlespancross-sectionis:𝑵𝒑𝒆=𝑴𝒔𝒘−𝟎.𝟕𝒇𝒕𝒌𝟏𝑨+𝒆𝒑𝒘𝑀𝑠=𝑀𝐺1+𝑀𝐺2+𝑀𝑄𝑠=3844.4𝑘𝑁∙𝑚Assume𝑎𝑝=100𝑚𝑚,thelengthfromthepointofresultantforcetothecrossgravityaxisis:𝑒𝑝=𝑦𝑏−𝑎𝑝=1156𝑚𝑚.Accordingtothefeaturesofallcrosssectiontoestimaterebar,theareaofmiddlespancross-sectionisA=876000𝑚𝑚2.Theelasticresistancemomentoftheallcross-sectiontotheresistancecrackingedge:W=𝐼𝑦𝑏=301.348×1091256=923.927×106𝑚𝑚3Sotheresultantforceofeffectivepre=appliedforceis:𝑁𝑝𝑒≥𝑀𝑠𝑤−0.7𝑓𝑡𝑘1𝐴+𝐸𝑃𝑊=2.3773×106𝑁Thecontrolst