雨篷受扭計(jì)算題

1、此題的計(jì)算過程和步驟僅供參考，此題是按舊規(guī)范做的，注意和新規(guī)范的區(qū)別7.2雨篷剖面見圖7-4。雨篷板上承受均布荷載（已包括板的自重）q=3.6kN/ma設(shè)計(jì)值），在雨篷自由墻沿板寬方向每米承受活荷載P=1.4kN/m（設(shè)計(jì)值）。雨篷梁截面尺寸240mm240mm,計(jì)算跨度2.5m.采用混凝土強(qiáng)度等級C25,箍筋為HPB235,縱筋采用為HRB335,環(huán)境類別為二a類。經(jīng)計(jì)算得知：雨篷梁彎矩設(shè)計(jì)值M14kNm,剪力設(shè)計(jì)值V23kN。試確定雨篷粱的配筋數(shù)量.（另：雨篷梁不做傾覆驗(yàn)算）If圖7-4習(xí)題7-2圖【解】已知：fc11.9N/mm2,ft1.27N/mm2,fyv210N.mm2,fy30

2、0N/mm2h0=240-35=205mm1 .雨篷梁所受扭矩的計(jì)算沿梁跨度方向單位長度上的扭矩t0.240.241.3t1.31.43.601.35.60kNmm222，1設(shè)計(jì)扭矩T1tl022 .截面特征量計(jì)算1“cc5.602.5027kNmb240Wt3hb3240240660.461107mm3bcor24050190mm兒。24050190mm42Acorbcorhcor1901903.6110mmcoicoicoiucor2bcorhcor2190190760mmcoicoicoi3.截面尺寸復(fù)核hw205一4b24022.37Nmm2231037106bh00.8Wt24020

3、50.8-0.461-107<0.25cfc0.251.011.92.975Nmm2截面尺寸符合要求。4.是否需按剪扭計(jì)算VT23103bh0Wt24020571060.4611071.986Nmm20.7ft0.71.270.889Nmm2需進(jìn)行剪扭計(jì)算。5.確定受剪及受扭箍筋(1)受扭所需箍筋量計(jì)算剪扭構(gòu)件受扭承載力降低系數(shù)t1.505黑1.5371.301.0,23100.4611010.567106240205故取t1.0令配筋強(qiáng)度比1.2Ast1T0.35tftWtSt1.2.fyvAcor71060.3511.270.4611071.2.1.22103.611040.497m

4、m2mm(2)受剪所需箍筋數(shù)量3nAsv1V0.7(1.5t)ftbh023100.71.51.01.27240205Sv1.25fyvh01.252102050.021mm2mm若選用雙肢箍,n=2,則單肢箍總的箍筋用量為*Asv1SSvAst1St0.02120.4970.508mm2mm78.5選用捱肋直徑10,Asv178.5mm2,s154.5mm,取s150mm0.508最小配箍率驗(yàn)算：ft1.27svmin0.28t0.280.17%fyv210實(shí)際箍筋配筋率:nAsv1svbs278.50.44%240150sv,min0.17%配箍率滿足要求6 .計(jì)算抗扭縱筋用量Astlfy

5、vAst1ucorfyvucorAmfySfy1.22107600.5082324mm300抗扭縱筋最小配筋率:Vb71061.27231032402.0取T1.27Vbtl,min0.6Vbftfy0.61.271.273000.286%實(shí)際抗扭縱筋配筋率:Astltlbh3240.56%240240sl,min0.286%滿足要求7 .計(jì)算抗彎縱向鋼筋數(shù)量:0.117141061fcbho1.011.92402052b0.55112s1120.1170.124A1fcbhc1.011.92402050.1242As242mmfy300抗彎縱筋配筋率：A0242f1270.49%minmax0.2%,45-450.19%bh0240205fy3008 .確定縱筋總用量：頂部：