屋面天沟排水计算书

屋面天沟排水计算书设计资料工程所在地设计最大降雨强度为250mm/hr天沟水深设计系数（设计水深度除天沟深度）为0.8，落水效率系数（落水管排水深度除设计水深度）为0.95屋面排水布置简图如下所示:设计结果表1天沟设计结果天沟号分担宽度雨水量天沟宽天沟深泄水坡度排水量通过1210000.01052502000.0010.017219是2420000.0213002100.0010.023528是3420000.0213002100.0010.023528是4210000.01052502000.0010.017219是表2集水范围内单根落水管设计结果天沟号分担宽度雨水量落水管个数落水管外径流水量通过1210000.0105111000.013556是2420000.021111600.035561是3420000.021111600.035561是4210000.0105111000.013556是详细验算过程1天沟1详细验算工程所在地设计最大降雨强度Rain=250mm/hr集水长度L=72/(11-1)=7.2m分担宽度B=21m集水面积Area=LxB=7.2x21=151.2m2分担雨水量Qr=AreaxRain/1000/3600=151.2x250/1000/3600=0.0105m3/sec天沟彩色板摩擦系数n=0.0125天沟宽度Bc=0.25m天沟设计水深Hc=0.2x0.8=0.16m天沟泄水坡度S=0.001天沟泄水面积Ag=BcxHc=0.25x0.16=0.04m2天沟泄水系数R=Ag/(Bc+2xHc)=0.04/(0.25+2x0.16)=0.070175m天沟排水速度Vg=R2/3xS1/2/n=0.0701752/3x0.0011/2/0.0125=0.43048m3/sec天沟排水量(采用曼宁公式计算)Qg=AgxVg=0.04x0.43048=0.017219m3/sec>0.0105m3/sec合格落水管外径d=0.1m落水管口面积A=nxd2/4=3.1416x0.12/4=0.007854m2考虑集水长度内1根落水管水流量重力加速度g=9.8m/sec2天沟设计水深Hc=0.2x0.8=0.16m落水管设计系数R=0.95落水管水流量Qc=mxAx(2xgxHcxR)1/2=1x0.007854x(2x9.8x0.16x0.95)1/2=0.013556m3/sec2天沟2详细验算工程所在地设计最大降雨强度Rain=250mm/hr集水长度L=72/(11-1)=7.2m分担宽度B=42m集水面积Area=LxB=7.2x42=302.4m2分担雨水量Qr=AreaxRain/1000/3600=302.4x250/1000/3600=0.021m3/sec天沟彩色板摩擦系数n=0.0125天沟宽度Bc=0.3m天沟设计水深Hc=0.21x0.8=0.168m天沟泄水坡度S=0.001天沟泄水面积Ag=BcxHc=0.3x0.168=0.0504m2天沟泄水系数R=Ag/(Bc+2xHc)=0.0504/(0.3+2x0.168)=0.079245m天沟排水速度Vg=R2/3xS1/2/n=0.0792452/3x0.0011/2/0.0125=0.46682m3/sec天沟排水量(采用曼宁公式计算)Qg=AgxVg=0.0504x0.46682=0.023528m3/sec>0.021m3/sec合格落水管外径d=0.16m落水管口面积A=nxd2/4=3.1416x0.162/4=0.020106m2考虑集水长度内1根落水管水流量重力加速度g=9.8m/sec2天沟设计水深Hc=0.21x0.8=0.168m落水管设计系数R=0.95落水管水流量Qc=mxAx(2xgxHcxR)1/2=1x0.020106x(2x9.8x0.168x0.95)1/2=0.035561m3/sec>0.021m3/sec合格3天沟3详细验算工程所在地设计最大降雨强度Rain=250mm/hr集水长度L=72/(11-1)=7.2m分担宽度B=42m集水面积Area=LxB=7.2x42=302.4m2分担雨水量Qr=AreaxRain/1000/3600=302.4x250/1000/3600=0.021m3/sec天沟彩色板摩擦系数n=0.0125天沟宽度Bc=0.3m天沟设计水深Hc=0.21x0.8=0.168m天沟泄水坡度S=0.001天沟泄水面积Ag=BcxHc=0.3x0.168=0.0504m2天沟泄水系数R=Ag/(Bc+2xHc)=0.0504/(0.3+2x0.168)=0.079245m天沟排水速度Vg=R2/3xS1/2/n=0.0792452/3x0.0011/2/0.0125=0.46682m3/sec天沟排水量(采用曼宁公式计算)Qg=AgxVg=0.0504x0.46682=0.023528m3/sec>0.021m3/sec合格落水管外径d=0.16m落水管口面积A=nxd2/4=3.1416x0.162/4=0.020106m2考虑集水长度内1根落水管水流量重力加速度g=9.8m/sec2天沟设计水深Hc=0.21x0.8=0.168m落水管设计系数R=0.95落水管水流量Qc=mxAx(2xgxHcxR)1/2=1x0.020106x(2x9.8x0.168x0.95)1/2=0.035561m3/sec>0.021m3/sec合格4天沟4详细验算工程所在地设计最大降雨强度Rain=250mm/hr集水长度L=72/(11-1)=7.2m分担宽度B=21m集水面积Area=LxB=7.2x21=151.2m2分担雨水量Qr=AreaxRain/1000/3600=151.2x250/1000/3600=0.0105m3/sec天沟彩色板摩擦系数n=0.0125天沟宽度Bc=0.25m天沟设计水深Hc=0.2x0.8=0.16m天沟泄水坡度S=0.001天沟泄水面积Ag=BcxHc=0.25x0.16=0.04m2天沟泄水系数R=Ag/(Bc+2xHc)=0.04/(0.25+2x0.16)=0.070175m天沟排水速度Vg=R2/3xS1/2/n=0.0701752/3x0.0011/2/0.0125=0.43048m3/sec天沟排水量(采用曼宁公式计算)Qg=AgxVg=0.04x0.43048=0.017219m3/sec>0.0105m3/sec合格落水管外径d=O.lm落水管口面积A=7txd2/4=3.1416x0.12/4=0.007854m2考虑集水长度内1根