API 5L X42 Pipe

[childressva01]

I am about to spec an arch bridge which uses circular pipe for the arch (16" dia) and tie (11.75" dia). I have been told that it will probably be API 5L pipe. I assume this is differnet from the ASTM specs quoted in the AISC HSS Steel Design Manual.

How is the API 5L formed? Although the AISC HSS manual does not list API 5L in it's approved materials, if I am careful to use the correct values for Fy, E, and Fu, can I still use their design specs?

 

[1969grad]

The specified minimum yield stress for API 5L Grade X42 pipe is 42,000 psi. The max allowable stress is percular to the code that you are using.

E is 29.5 E+06 psi at 70 F.

Using a wall thickness of 2.125" may require pre-heating and post heat (stress releaving) of butt weld joints.

Manufacturing types of API 5L pipe can be seamless or have ERW (not recommended) or DSA welded longitudinal joints which may require derating the allowable stresses.

 

[JStephen]

11.75" is not a normal pipe size- are you sure this is correct?

I would expect to see A53-B or A500-B for an application like that, although a lot of different materials could be used.

And where did 2.125" thickness come from?

You may also want to check how the different codes handle tolerances on wall thickness.