Geberit Gutter size dimension verification

Gutter Dimension verification as per GB50400-2006根据GB50400-2006来验证天沟尺寸
GB 50400-2006 Gutter Size calculation 天沟尺寸计算
1.Introduce the way of gutter size calculation according to GB50400-
2006 (Engineering technical code for rain utilization in building and sub-district)
介绍GB50400-2006（建筑与小区雨水利用工程技术规范）上所提及的天沟尺寸计算方法
parison between GB’s way and Geberit’s way in calculating
gutter size
比较国标和吉博力在计算天沟尺寸方面的不同
3.What we still need to know
讨论我们还需要知道哪些东西
Application scope:应用范围应用范围：：
When the gutter has no slope or its slope is not larger than 0.003用于天沟为平坡或者坡度不大于0.003时
GB 50400-2006 Gutter Size calculation 天沟尺寸计算
Horizontal short gutter calculation formula:水平短天沟计算公式：Q dg =k dg k df A z 1.25S x X x
q dg : the drainage capacity of horizontal short gutter (L/S);
水平短沟的设计排水量（L/S)
K dg : factor for safe, the value is 0.9; 安全系数，取值0.9
k df : transect factor, see table 1.1; 断面系数，取值见表1.1
A z : effective transect size for gutter (mm 2);沟的有效断面面积（mm 2)
S x : depth factor, please see attached B, for semicircle or similar shape short eaves gutter S x =1.0;
深度系数，请参见附录B,半圆形或相似形状的短檐沟S x =1.0
X x : shape factor, please see attached B, for semicircle or similar shape short eaves gutter X x =1.0
形状系数，请参见附录B,对半圆形或相似形状的短檐沟X x =1.0
GB 50400-2006 Gutter Size calculation 天沟尺寸计算
Table 1.1 Transect factor for different gutter types 不同类型天沟的断面系数
3.89*10-5
3.48*10-5
2.78*10-5
k df
Rectangle
or trapezium or similar gutter and brim gutter 矩形、梯形或相似形状的天沟和边沟Rectangle
or trapezium or similar eaves gutter
矩形、梯形或相似形状的檐沟Semicircle or similar eaves gutter
半圆形或相似形状的檐沟
Gutter type 天沟类型
GB 50400-2006 Gutter Size calculation 天沟尺寸计算
Horizontal long gutter drainage capacity calculation:水平长天沟设计排水量计算水平长天沟设计排水量计算：：Q cg =q dg *L x
q cg : design drainage capacity for long gutter (L/S)
长天沟的设计排水量（L/S)
L x : factor for long gutter drainage capacity, see table2.1
长天沟容量系数，见表2.1
GB 50400-2006 Gutter Size calculation 天沟尺寸计算
Table 2.1 factor for long gutter drainage capacity
平底或有坡度坡向出水口的长沟容量系数 1.551.401.251.100.73300 1.55
1.40
1.25
1.10
0.63
450
1.551.401.251.100.77250 1.551.401.251.100.80200 1.371.271.171.070.86150 1.181.131.081.030.93100 1.001.001.001.001.00501%0.8%0.6%0.4%0-0.3%
Lx
L/h d
Note: L means length for drainage (mm); L 指排水长度（mm)
h d means design water height (mm); h d 指设计水深（mm)
GB 50400-2006 Gutter Size calculation 天沟尺寸计算
For gutter and brim gutter, the minimum protective height mustn’t be less than the following:对天沟和边沟对天沟和边沟，，最小保护高度不可以小于表中值最小保护高度不可以小于表中值：：
75
>250
0.3h z 85--25025<85The minimum protective height (mm)最小的保护高度（mm)h z (mm) (The gutter height including the protective height)（包含保护高度的天沟高度值）GB 50400-2006 Gutter Size calculation 天沟尺寸计算
Depth factor, for semicircle or similar shape short eaves gutter Sx=1.0;深度系数，请参见附录B,半圆形或相似形状的短檐沟Sx=1.0
Shape factor, for semicircle or similar shape short eaves gutter Xx=1.0
形状系数，请参见附录
B,对半圆形或相似形状的短檐沟Xx=1.0
GB 50400-2006 Gutter Size calculation 天沟尺寸计算
Depth factor
Shape factor
An example for calculation:计算举例计算举例：：1.The roof size is : length is 100m; width is 70m;
屋面尺寸为：长100m, 宽70m;2.The rain quantity is 0.05851l/s.m 2雨量值取0.05851l/s.m 2;
3.
The gutter size is 100m length; 300mm depth;天沟尺寸长100m,深300mm;
The slope of the roof is 5%; the gutter has no slope; the gutter Shape is rectangle brim gutter
屋面坡度是5%;天沟是平坡；天沟是矩形的边沟；Please calculate the gutter’s width 请计算天沟宽度
GB 50400-2006 Gutter Size calculation 天沟尺寸计算
GB 50400-2006 Gutter Size calculation 天沟尺寸计算
计算））
Calculation: （计算
1.s=100*70=7000m2
2.Q=7000*0.05851=409.57l/s
3.Choose 10 outlets, each drainage capacity is 41l/s
选择10个斗，每个斗的排量是41l/s
4. Put the outlets evenly in the gutter, the distance between two outlets is 10m
把斗均匀地布置在天沟中，斗间距为10m
5.L/hd=5000/225=22.2, so Lx=1
6.We suppose the width of the gutter is 500mm, so we can get each factor:
我们假设天沟的宽度是500mm,这样我们可以得到每个参数并计算出：
q dg =k dg k df A z1.25S x X x=0.9*3.89*10-5*(225*500)1.25*0.8*1=57.7l/s>41l/s
So this width is safe for such situation 因此对这样的设计条件假设的天沟宽度是够安全的
GB 50400-2006 Gutter Size calculation 天沟尺寸计算
distance between two outlet which has influence for gutter
drainage capacity ,
根据这张表格，它无法反映出不同的斗间距对
天沟排水能力的影响
We check from this table, in such situation, the width of the
gutter is almost 650mm-700mm, which is almost not
acceptable by architect.
从这张表格中我们可以得出，在以上相同的
设计条件下，天沟的宽度大约是650mm-700mm
GB 50400-2006 Gutter Size calculation 天沟尺寸计算
What we still need to know:
我们还需要知道些什么：
1.How to calculate the gutter has slope more than 1%
怎样计算坡度大于1%的天沟
2.How to calculate the gutter which has big radius
怎样计算带弧度的天沟
3. How to calculate, if we set not only a syphonic drainage system, but also a syphonic
overflowing system
如果我们不仅设计了虹吸排水系统，而且还设置了虹吸溢流系统
时，怎样计算天沟。