I recently saw a "solution". There was only one trunion. In P91 MS line. We did quick FEA. Over the limits off cause. Trunions fail on lines operating in creep range even without any support load. On lines in creep range:
- don't use trunions
- never weld support item on outside surface of the bend
- never even think of welding something on longitudinally welded elbow/bend outside surface
- If you still do any of the above please let me know the plant. We are considering starting a company to remove such items :-)