How do you engineer a pipeline ditch?

Question

how do you engineer a gas pipeline ditch for bending the pipe?

Answer 1

"how do you engineer a gas pipeline ditch for bending the pipe?"

Just so you know, I have never done this. I usually design a trench to carry a pipe and any surcharge. I specify the pipe bends or manholes.

If the pipe is designed to bend under a moderate backfill load, you need to find the typical curvature the pipe deflects and then determine the amount of deflection per 10' under a typical three foot trench. Make sure this doesn't exceed the maximum allowable deflection.

Draw the vertical profile showing the existing ground and your pipe's proposed vertical alignment. Does the pipe exceed the maximum?

It takes engineering.

Answer 2

what is the pi9peline carrying, if its storm water or anything under gravity flow. getting the grade and slope of the ditch is critical or the water will not flow. If its anything being pumped or under sufficient pressure, this is much less critical.

The other things are to identify any conflicts (buildings, roads, other utilities, etc.) in the path of the one being engineered. route your lines away from as much stuff as possible.

Remember that water and sewer lines must be separated by at least 10 feet. Most other materials must also be seperated from water.

Once you have the routing and the flow rate, you can calculate the pipe size/ diameter- it usually take an engineer to do this or somebody with a lot of experience could read the pressure drop charts and come up with the correct size. Many times, experience is also acceptable.

The last thing to do is select the material of construction- once again it depends what the material is. Concrete lined ductile iron pipe is the bes for water and sewr projects. Carbon steel with cathodic protection is best for petroleum products over long distances. Fiberglass is okay for short distances.