Recent content by gusongjun

To bimr: Thanks for your reply. Problem is I don't know how many people will work in each building. What I know is building layout. So I know the amount of closets, sinks, showers and so on. Then, I converted fixture units counted into water discharged (all consumped water will be discharged...

I am designing underground sanitary system in an industrial area. To calculate effluent rate, Fixture Unit method is used. Effluent to MH1 = 5.8 l/s MH2 =7.185 l/s MH5=2.032 l/s MH7=2.132 l/s Question 1: From Manhole 2 to Manhole 5, I add 5.8 l/s + 7.185 l/s = 12.995...

To bimr The pipe is new installed in industrial area for waste water. Before installation, dewatering had been done to dry trench.

There is 300 mm bedding sand for those pipes. Bedding sand shall be comptacted to 98% SPMDD. So I think 50 mm tolerance is not tight. But the contractor intalled pipes some where is out of tolerance. The worst place is 78 mm deviation. Gee, do you guys have meet same suitation? Thanks!

To cvg Yes, I permitted 50 mm deviation of elevation for contractor. I don't know why they can't install pipe within the tolerance. These pipes are not big or heavy. Gee.

Thanks. These pipes are 8" and 10". As built deviation is around 100 mm. Without any sepecial reason, I think 100 mm deviation is acceptable. Do you have any similar experience?

See below, Assume the distance manhole to manhole is 180 m, slope is 1.5%, so the actual length along the profile is SQRT(180^2+(180*1.5%)^2)=180.020 m. Do you think there is a big problem with 180 m and 180.020 m? Usually only horizontal distance is used.

Hi, guys, I have some deep underground HDPE pipes, DR 9 and DR 11. I am wondering who know elevation(grade) deviation for these kind of pressured pipes. Many thanks for your kind consideration. Any reply is greatly appreciated. Best regards,

don't forget the factor of safety, compact load too.

I only saw on line installed on the top of pipe. Then those pipe were buried. I thought a lot portable equipments can detect those underground pipes. Usually burial depth shall be less than 3 to 4 meters.

Horizontal curves usually connected by tangential straight lines. The length of tangential lines shall be not less than 4 times design speed. For example, design speed is 60 km/h, the minimum length of tangential line shall be 240 m. Regarding spacing vertical curves, I can’t remember any...

To cvg: Thank you! I don't mean tolerance of pipe invert grad and line. I want to what the tolerance for concrete manhole. I heard that tolerate for elevation is <=10 mm, elevation is <=10 mm as well.

Sorry. I might confuse you. For the tolerance, I mean as-built coordinates/elevation is not same designed coordinates/elevation. So the tolerance for this difference. Many thanks for your kind concern. Best regards,

Tolerance for offset.

to SNORGY Thanks for your reply.