Wind Induced Vibration in Pipeine Supports

[99501]

Does anyone have knowledge of there being a significant difference in structural fatigue from wind inducted vibration on single vertical pipeline supports (VSMs) verses two vertical support members for cross-country pipeline racks? My presumption is, without pipeline vibration dampers (PVDs) on the pipeline span, wind-induced pipeline oscillations are going to stress the welds on the horizontal members of the VSM... If only one support, that means both horizontal arms of the VSM (a T shape) are going to "wobble"... if there are two vertical supports, the inner span between the two posts (now a TT shape) should provide enough structural rigidity to the horizontal pipeline saddle to channel the vibrations thru the vertical posts to ground. Your experience with this phenomenon is appreciated.Pipeline span lengths are 40-65 feet; wind speeds up to 100 mph. Arctic pipe 8- to 24-in diameter. Some pipe racks have 2 pipes on each side of the VSMs, or 1 pipe on one side and 2-3 on the other; others have a single pipe on one side (24-in). Embedment depth on the vertical post are 15 ft. to 70 ft. Posts do jack due to freeze-thaw cycles.