I am involved with a project that involves replacing the wye block on a main steam system that has piping that is cold sprung piping.

The piping system consists of a main riser coming down from the boiler connection. The riser is anchored in x-y-z direction but not rotation. At the bottom of the riser is a forged wye block. The piping exits the wye block at 45 degrees from the vertical. The two pipes continue to diverge from each other and also bend (approx 5D) to the horizontal. The horizontal pipes continue to the main steam stop valves. There are cut short lengths in both the vertical riser and the horizontal lengths of pipe.

The project will involve cutting the wye block out of the piping system. But before I do that I need to design and install restraints the will hold the piping ends in their relative positions when the wye block is removed and not allow them to spring back out of position.

I have a model showing the existing piping, including the cut short sections. I will add restraints to the model. I need to develop output from Caesar that will show the pipe ends are not moving when the wye block is removed.

Suggestions?

You may find the pipe has become self sprung... what temperature does it run at and how long has it been at that temperature?

If it has become self sprung the Caesar II model will be unable to predict the behaviour. CAESAR II performs a simplified elastic analysis per the B31 codes.

The pipe operates at about 1000 F and it has been in service for over 10 years.

Yes, I realize there may have been some relaxation of the cold spring over time, but I would like to get results assuming no relaxation before I make a judgment regarding the amount of cold spring relaxation.

OK then take a look at what is to be found in the technical refernce manual under cold spring I am sure this will be of some help.