長安大學(xué)結(jié)構(gòu)設(shè)計原理課程設(shè)計-全文預(yù)覽
【正文】 1+1127329725610983000001017000007740000003801716505792455+11+11+1127329725610983000001017000007740000003801716505792455+11+11+112732972561098300000101700000774000000Principal tensile stressPrinciple tensile stress calculation table in changing point section計算纖維SnS39。0x0S0aS0x0 面積距239266511264139987 aax0x0 Vq= τ= 正應(yīng)力 計算纖維面積距剪應(yīng)力τ正應(yīng)力σ主應(yīng)力NpⅡ= 第一階段凈面積Sn第二階段凈面積S39。0x0S39。0x0S39。0x0S39。Reinforcement stress at force anchor , (5)Stress losses caused by concrete creep and shrinkage：Stress losses caused by concrete creep and shrinkage could calculate by use the following formula:、——load age is , final value of concrete shrinkage strain, and final value of concrete creep.——Load age，the load age till the 90% of the design strength， , ；To the second stage dead load , the load age , assume =90d；The bridge is at the mon area of field. The relative humidity is 75%，thickness of the member (I－I section), get ，check the table, get the final value of creep coefficient ；The final value of concrete shrinkage strain .the average value of normal stress at the midspan section l/4 section。 the distance from tensioned to anchor end, the anchor end is midspan crosssection. The influence length of friction shows in the following Table. Table of friction influence length截面鋼束編號跨中N1139515486N2139515586N3139515642L/4N113957821N213957921N313957977變化點N113953856N213953956N313954012支點N11395156N21395256N31395312We know all ,the prestress losses after considering friction is : is the tensioned prestressed losses after considering friction caused by anchor deformation,. If , then friction have no influence on this section. Calculation of each control section’s are shown in the following Table.(2)錨具變形，鋼絲回縮引起的應(yīng)力損失截面鋼束編號xlf△σσl2各截面σl2平均值跨中截面xi=0N11348611854xlf截面不受反摩擦影響0N21358610361N31364210377L/4截面xi=8165N1832111854N2842110361N3847710377變化點截面xi=11630N1385611854N2395610361N3401210377支點截面xi=153630N115611854N225610361N331210377(3)Concrete elastic pression caused prestress lossesFor simple supported beam, calculate l/4 section, and take its value as the whole beam crosssection’s prestressed reinforcement losses’ average value:mTension batch number, m=3。radN1 N2 N3 L/4截面鋼束編號θθμXkx1e(θμ+kx)σσl1176。 is the friction coefficient of reinforcement and pipe and is the local deviation of pipe per meter length’s influence on the friction coefficient, we know 。cosθ0=2098cos8176。m)Assume ；then the length from the point of resultant force to the cross gravity axis is:；According to the features of all cross section to estimate rebar,the area of middle span crosssection is: A=876000；The elastic resistance moment of the all cross section to the resistance cracking edge: .So the resultant force of effective preapplied force is:Npe=(Ms/)/(1/A+ep/W)=(3823106/)/(1/876000+1156/239927000) =2359158NThe control stress of prestressed rebar is .The prestress losses are estimated as 20% ,We can get the area of prestressed reinforcement is:Ap=Npe/()σcon=2359158/(1395)=2114(mm2)To use 3 bundle strands, the area of prestressed reinforcement is :Ap=36140=2520(mm2). And use the strand tapered group anchors, metal corrugated pipe into the hole.2) Lay out prestressed reinforcement.(1)Arrangement of prestressed rebar in midspan section:According to the requirement of The Road Bridge Gauge,arrangement of prestressed reinforcement in midspan section shown Figure 3.(2)Lay out steel cable of anchor crosssection: Fig1. End of prestressed beam anchor position in the end cable position in midspanIn order to be convenient for construction,three steel cables anchor end of beam,which fits principle of homogeneous disperse and requirement of will offer much preshear force by bending more depth of N1 and N2 in end of beam. The all shown Fig1 and Fig2.(3):Location and angle of steel cable from other sections.①Bending shape、angleθ and radius of bending.Obtain interpolate curve between stra
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