## Thrust block for water pipe hanging from the bridge structure

## Thrust block for water pipe hanging from the bridge structure

(OP)

I have a new 14" (ID) ductile iron potable water pipe hanging from the bridge structure. The pipe is approximately 600' long, relatively horizontal, working water pressure is 100 psi, 1500 gpm (max). The pipe will be installed in the snow country. I need to design thrust block for the pipe line. The thrust block system will be steel structural members that brace the pipe to the bridge structure. I see formula for the thrust block design for buried pipe but nothing on the pipe hanging from the bridge. Questions:

1. Can I still use the T = 2 P A (sin Q/2) equation to calculate the thrust force?

2. Is the Area of the pipe, inside or outside diameter of the pipe?

3. Is the water pressure A, actual working water pressure inside of the pipe (that is active 24 hours a day), or is it the pressure rating of the pipe material (350 psi), which is more than three times the actual working water pressure of 100 psi?

4. Any factor of safety I should consider for the thrust force calculations?

Thanks

1. Can I still use the T = 2 P A (sin Q/2) equation to calculate the thrust force?

2. Is the Area of the pipe, inside or outside diameter of the pipe?

3. Is the water pressure A, actual working water pressure inside of the pipe (that is active 24 hours a day), or is it the pressure rating of the pipe material (350 psi), which is more than three times the actual working water pressure of 100 psi?

4. Any factor of safety I should consider for the thrust force calculations?

Thanks

## RE: Thrust block for water pipe hanging from the bridge structure

Looks like straight pipe there. If you have 90° elbows at the ends of this, then yes, that's the formula. If not, where are you putting the blocks? But not sure how you will handle thermal expansion/contraction of the pipe between two thrust blocks.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

## RE: Thrust block for water pipe hanging from the bridge structure

Remember - More details = better answers

Also: If you get a response it's polite to respond to it.

## RE: Thrust block for water pipe hanging from the bridge structure

The rollers are common. Problem is the joints.

https://www.mcwaneductile.com/blog/key-considerati...

https://www.wsscwater.com/sites/default/files/site...

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

## RE: Thrust block for water pipe hanging from the bridge structure

Restrained Joints

Link

## RE: Thrust block for water pipe hanging from the bridge structure

1. Is the Area of the pipe, inside or outside diameter of the pipe?

3. Is the water pressure A in the formula, actual working water pressure inside of the pipe?

4. Any factor of safety I should use?

## RE: Thrust block for water pipe hanging from the bridge structure

3. The design pressure would be the max pressure that can be expected in the pipe

## RE: Thrust block for water pipe hanging from the bridge structure

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

## RE: Thrust block for water pipe hanging from the bridge structure

1. Is the Area of the pipe, inside or outside diameter of the pipe?

A= External diameter of the pipe. Consider the socket joints.The gross pipe area ( A) subjected to pressure .

3. Is the water pressure A in the formula, actual working water pressure inside of the pipe?

A= Water pressure (P) in the formula, test pressure inside of the pipe.

4. Any factor of safety I should use?

A= In past , i have used min. F.S.=2.0 . This must be decided with OHJ , client ..

Good luck.

Use it up, wear it out;

Make it do, or do without.

NEW ENGLAND MAXIM

## RE: Thrust block for water pipe hanging from the bridge structure