Omega Radio Tower - Trelew, Argentina

Omega Radio Tower - Trelew, Argentina

The Loizeaux Group, LLC

With the broadening of satellite navigation systems into the private sector, the world-wide Omega Navigation System, built in the 1970’s to aid maritime navigation, became obsolete. Under agreement with the Argentine Naval Hydrographic Service Center, the U.S. Naval Facilities Command in San Bruno, California, entered into a contract with National Steel Erectors/Tower Inspection, Inc. (NSE) of Muskogee, Oklahoma, for the salvage of certain equipment and the demolition/removal of the tower, its top-hat array and stays, without damage to the helix house located just 25’ away from the tower’s base.

Aided in the structural analysis and structural design of the project by Tryck Nyman Hayes, Inc. of Kingston, Washington, NSE hydraulically jacked the tower up against the balanced tension of the stays, removed the base insulator, inserted a steel and concrete surrogate insulator and lowered the tower back down. Two (2) weeks earlier, NSE had engaged CDI to design a plan to fell the 1,202’-6” tall structure without damage to the helix house 25’ away.

Operating under severe time constraints, CDI was unable to ship U.S.-made linear shaped charges for the project. A CDI representative flew to Buenos Aires where the local explosives supplier had expressed confidence in their ability to melt and pour pentolite explosives in CDI furnished copper sheathing to a density specification provided by CDI.

After National completed salvage of the base insulator, helix house bushing and other U.S. Navy-specified equipment, CDI successfully tested several of the Argentinean-made charges against cable linkages isolated by prior lowering of all but four of the top-hat radials. With those successful tests, CDI placed the Argentinean charges to sever links to free two of the remaining four top-hat radials, and the five structural cable stays on one side of the tower.

On detonation, the Argentinean charges cleanly severed linkages for the top-hat radials and lower four structural guys. However, unobservable bubbles in the center of the charges used on the 5th level guy interrupted formation of the penetrating jet, yielding incomplete severance. The resultant release of the tower above and below the 5th guy produced an almost vertical collapse of the tower resulting in a fall area of steel much smaller than would have been used had the structure fell its full height with release of all of the structural guys.

Inadvertently, and without damage to the helix house, a far more aggressive means of felling large guyed towers was demonstrated. Subsequent analysis of the structural release sequence of the guys has yielded predictable data which CDI intends to use in the felling of large, cable-stayed towers in the future.