C型檩条计算书

2网架屋面主檩条计算采用140x80x4钢通檩条，按3.6m跨度的连续梁计算，檩距3.7m，檩条材料的屈服强度为215MPa，其毛截面特性为：A=16.96cm²Ix=449.35cm4Iy=186.76cm4Wx=64.19cm³Wy=46.696cm³g=13.32kg/m倾角取最大处倾角a=4゜,由于角度太小，故不考虑角度对荷载的影响。(1)荷载计算1)恒荷载屋面系统自重0.5kN/m²小计0.09020.5kN/m²×3.7m=1.85kN/m配件0.04710.1kN/m檩条自重0.03540.1332kN/m合计0.2362.0832kN/m2)活荷载0.5Kpa×3.7m=1.85kN/m3)风荷载基本风压：0.7kN/m²体型系数：-1.2负风压标准值wk1=-2.0827kN/m²正风压标准值wk2=0.5kN/m²负风压-2.0827×3.7=-7.706kN/m正风压0.5×3.7=1.85kN/m4).雪荷载雪压标准值sk=0Kpa雪压0×3.7=0kN/m(2)荷载组合向下最不利组合值：恒＋风＋雪=2.0832×1.2＋1.85×1.4×0.6+0×1.4=4.053kN/m恒＋风＋活=2.0832×1.2＋1.85×1.4×0.6+1.85×1.4=6.643kN/m向下最不利标准值：恒＋风＋雪=2.0832×1.0＋1.85×1.0×0.6+0×1.0=3.193kN/m恒＋风＋活=2.0832×1.2＋1.85×1.4×0.6+1.85×1.4=5.043kN/m向上最不利组合值：恒＋风=2.0832×1.0-7.706×1.4=-8.705kN/m向上最不利标准值：恒＋风=2.0832×1.0-7.706×1.0=-5.622kN/m所以最不利的荷载为：向下:最不利荷载设计值Wf=6.643kN/m最不利荷载标准值Wk=5.043kN/m向上:最不利荷载设计值Wf=-8.705kN/m最不利荷载标准值Wk=-5.622kN/m(3)内力计算（按多跨连续梁计算）Mxmax=0.105×Wf×L²=0.105×8.705×3.6×3.6=11.85kN.m(4)强度计算σ=Mxmax/W=11.85×1000000/64.19/1000=184.61N/mm²f=215N/mm²强度满足要求(5)挠度计算（按多跨连续梁计算）vmax=0.644×Wk×L^4/100EI=0.644×5.622×3600^4/100/206000/449.35/1000=6.56mm[v]=L/250=3600/250=14.4mm刚度满足要求3网架屋面次檩条计算采用C120x60x20x2.0冷弯薄壁檩条，按4m跨度的连续梁计算，檩距1m，檩条材料的屈服强度为215MPa，其毛截面特性为：A=5.44cm²Ix=127.04cm4Iy=28.81cm4Wx=21.17cm³Wy=13.42cm³g=4.28kg/m倾角取最大处倾角a=4゜,由于角度太小，故不考虑角度对荷载的影响。(1)荷载计算1)恒荷载屋面系统自重0.5kN/m²小计0.09020.5kN/m²×1m=0.5kN/m配件0.04710.1kN/m檩条自重0.03540.0428kN/m合计0.2360.6428kN/m2)活荷载0.5Kpa×1m=0.5kN/m3)风荷载基本风压：0.7kN/m²体型系数：-1.2负风压标准值wk1=-2.0827kN/m²正风压标准值wk2=0.5kN/m²负风压-2.0827×1=-2.083kN/m正风压0.5×1=0.5kN/m4).雪荷载雪压标准值sk=0Kpa雪压0×1=0kN/m(2)荷载组合向下最不利组合值：恒＋风＋雪=0.6428×1.2＋0.5×1.4×0.6+0×1.4=1.191kN/m恒＋风＋活=0.6428×1.2＋0.5×1.4×0.6+0.5×1.4=1.891kN/m向下最不利标准值：恒＋风＋雪=0.6428×1.0＋0.5×1.0×0.6+0×1.0=0.942kN/m恒＋风＋活=0.6428×1.2＋0.5×1.4×0.6+0.5×1.4=1.442kN/m向上最不利组合值：恒＋风=0.6428×1.0-2.083×1.4=-2.273kN/m向上最不利标准值：恒＋风=0.6428×1.0-2.083×1.0=-1.44kN/m所以最不利的荷载为：向下:最不利荷载设计值Wf=1.891kN/m最不利荷载标准值Wk=1.442kN/m向上:最不利荷载设计值Wf=-2.273kN/m最不利荷载标准值Wk=-1.44kN/m(3)内力计算（按多跨连续梁计算）Mxmax=0.105×Wf×L²=0.105×2.273×4×4=3.82kN.m(4)强度计算σ=Mxmax/W=3.82×1000000/21.17/1000=180.45N/mm²f=215N/mm²强度满足要求(5)挠度计算（按多跨连续梁计算）vmax=0.644×Wk×L^4/100EI=0.644×1.44×4000^4/100/206000/127.04/1000=9.07mm[v]=L/250=4000/250=16mm刚度满足要求