AM Ground Systems Company

WSWK Atlanta GA

Summer 2005

WSWK was a very "unique" ground system build.  The new tower site is a large parking lot used by one of the City of Atlanta's utility divisions.  The original plan was to have a paving contractor grind the existing asphalt down to soil and then AGSC would plow in the new ground system.  We would then carefully grade the asphalt grindings and soil and then the paving contractor would simply pave over it again.  It was a good plan until the asphalt grinder was destroyed several times hitting subsurface obstructions.  Some research showed that this site had been used many years ago to dump iron ore slag and debris from a nearby (long closed) iron smelter.  Driving ground rods at this site was next to impossible due to the layers of iron slag and other debris underground.

Plan B...

Pull the radials out by hand and staple them to the existing (soft) asphalt with fence staples.  The paving contractor then installed a very expensive fabric and tar emulsion over the top of the radials and added a layer of asphalt.  A 24x24ft screen was built around the tower base which was conveniently located in the center of an abandoned concrete slab.  It rained sometime almost every day we were working on this site but as soon as the rain would stop we could go right back to work.  The nearest mud was several blocks away...


 




Big Bird sitting (setting?) among the freshly pulled radials






More Big Bird.

The dark area is an area built up with hot mix. There had been a concrete wall on this side of the wash pad as well. The hot mix made a much smoother transition from the pad to the parking lot.





The radials are visible on top of the asphalt.

We marked the end point of each radial with a paint dot and then drove a long concrete nail to secure the radial end. The radials were then pulled by hand to the nail and secured to it. Any areas of the radials that were suspended above the asphalt were stapled down with long fence staples.





The tower was setting on an old concrete wash pad. This is a retaining wall on the uphill side. The radials run up to and over the wall.

Treated 2x4's were screwed into the wall to keep the radials tight.





The other side of the wall. Treated 2x4's was used to keep the radials tight over the wall.

The wall and radials were later sprayed with tar to hide the nice shiny copper.





The white dots in the lower center of this frame are the radial ends. The posts in the background are for a fence around the guy anchor point.






The tower base grounding.

Lightning concerns prompted the client to require 12 ground rods driven around the tower base. One of the temp helpers is clamping the 2in strap to the main 8in strap ring. We use this setup when installing copper screen. The radials are installed first and bonded to the OUTER couple inches of the 8in strap. Then the screen is laid down and bonded onto the INNER few inches. More on that later.





A site requirement was to ground the guy wires for personal safety.

The row of 6 rods accomplished this. AM guy wires are broken numerous times with insulators. The grounding above only grounded the bottom 20ft of each guy. A lighting consultant from the City of Atlanta required this elaborate grounding scheme to give the workers a warm and fuzzy feeling. For this AM tower, a single rod would have been adequate.





Another view of the guy grounding and the short radials required by the cities lightning expert.






Close up of the exothermic bond to the rod.

We used a CadWeld product called "One Shot" for these connections. The One Shot product is a one time use ceramic mold that is great for wire to rod connections. The mold is inserted onto the wire and then onto the rod. The weld metal is poured in (not forgetting the metal disk lest you have an explosion of profanity when the weld metal falls thru the mold onto the ground), light it off and when cool the mold is simply broken with a tap from a hammer. This complete shot costs just slightly more than the just the weld metal for the large reusable molds (which we also use).





Side view of the screen and radials running off of the concrete pad.

The ding in the HVAC unit was the result of a conflict between the HVAC unit and a backhoe.

HVAC 0, Backhoe1





The screen with 4 inch strap around perimeter.

The screen with 4 inch strap around perimeter. The radials were bonded to the 8in main ground and the 4in perimeter strap..





Close up view of the tower base grounding.

This view shows the intricate copper work. We use .020x2in copper to bond the 8x24ft sections of the copper screen together. Even if a portion of the screen is damaged, the strap will allow the remainder to function normally. Most of the ground systems I have inspected over the years has had damage to the screen. Most ground system installers (not that there are very may of us now) simply wrap the edge's of the sections together and some even connect the radials to the outside edge of the screen. I have repaired MANY ground systems that used this scheme and have found it to be very unreliable. Visible in the background is a length of 4in strap that will be use to bond the large ATU into the system.





Close-up of base ground ring.

The radials are bonded to the outside of the large strap and the screen is bonded to the inside.





Huge candelabras.

Not really relevant to the WSWK site except they were visible toward Buckhead from the site.





More tower base grounding.

The building perimeter strap and the pier top grounding is visible here. Not visible is the copper strap directly grounding the lower side of the arc gap.





One of the 12ea 2in ground rod straps.

The 2in strap was exothermically bonded to the strap using Harger UltraWeld molds and materials. The strap was then brazed to the main tower base ground ring.





Jeremy (back left) slacking off while the temp guy (right front) works hard.

Also visible here are several of the 2in ground rod straps before they were trimmed.





Jeremy still slacking, the temp still working.






Looking basically north toward the back corner of the lot. The trailer visible in the background is used to transport AGSC equipment.






The JD 4600 in the background is our main ground system installation machine.

At this job it was nothing more than a very expensive reel holder.





The lot with radials visible.

The paving company posted a guard at the site every night to keep an eye on the nice shiny copper. It was their miscalculation that left the copper exposed. They were perpetually late or no show. They did good work but the foreman had no concept of time. His OR ours.





A close-up of a radial wrapped around a concrete nail at it's terminus.






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