Westchester at Peachtree Valley
Contractor: Cambridge Builders & Contractors Inc.
In 2007, we were asked to bid the barrier cables on a ten-story parking deck in Atlanta. The parking garage was a precast designed structure with spandrels on the exterior walls where cables were required. The spandrels were designed in such a way that they rose only 12 inches above the finished floor of the deck levels. Due to the lengths of the spans along these walls, intermediate posts were required to ensure the cables would meet code without needing excessive pre-tension loads.
Upon calculating cable loads and post design, we discovered that the spandrels could not handle the post-attachment design as desired due to the thinness of the spandrels. Through discussion between GSSI and the engineer, an economical solution emerged: we chose to utilize a strap plate welded to the base plate and attached by horizontal bolting to the face of the spandrels at a designed distance down from the top of the spandrels. This addition, along with the vertical bolting of the base plate, provided an economical solution as well as intermediate posts that would withstand code-mandated crash loads.
GSA – Spring Street
In June 2007, The Conlan Company requested a quotation for cable work on the General Services Administration parking deck at 180 Spring Street S.W. in Atlanta. The deck was only a three-story structure with barrier cables along the interior light wall (2400 LF). This project was unique due to the architect’s design consisting of a vertical cable system on the exterior wall to serve as a plant-climbing unit. This vertical cable system (23’ in height) was composed of forty stainless steel cables divided into four groups of ten. In addition to this, the system included four sets of galvanized anchorage angles attached to the wall utilizing all thread rod and Hilti Epoxy. Stainless steel turnbuckles were used to tighten the vertical cables. GSSI worked with the engineer, Uzon & Case, to finalize the stainless cable design and attachment.
Ocoee Whitewater Center Legacy Trail Bridge Repairs
U.S. Department of Agriculture – Forestry Service
The bridge is a 10’ wide by 336’ long steel frame superstructure with two steel 60’ high towers located at the quarter points. The deck is composed of wood planking and steel railings. There are 72 total stay cables installed between the towers and the superstructure of the bridge. The original epoxy-coated cables were installed in the spring of 1996. In 2010, we were asked to bid the replacement of the stay cables. After doing so, we were awarded the project. The original epoxy anchors were a Grabb-it style, with visible cracking in the anchors as well as a corrosion issue. The new design called for replacement with galvanized cables and new zinc-plated Grabb-it anchors. We utilized a rolling scaffold system to install the cables at the top of the tower. We replaced the old cables with new, as the old were removed. After total replacement was achieved, the proper camber was introduced in the bridge by means of tightening each cable in a multiple phase design sequence. After final tensioning, we made use of the rolling scaffold system to access the cables in order to apply an “environment matching” paint to the cables.
Total L.F. of cables 4,600 L.F. Cable lengths range from a long of 87 L.F. to short of 44 L.F.
Perimeter Mall Parking Deck Contractor:
Western Waterproofing Co. of America
In 2012, we were contacted to bid repair of loose barrier cables on a parking deck at Perimeter Mall. The deck was a five-story structure with a north ramp and a south ramp. There were a total of eight runs of cable on each side of the ramps and cables across each end on the fifth level. The project had a total of 374 cables. The existing cables were galvanized and appeared in good shape. The issue was that the cable barrel anchors were not galvanized and had corrosion issues in the wedges of the anchors. Cables were loosening and failing.
We were asked to propose a repair to the system to de-tension the cables that existed. We presented the issue to the owner that the existing barrel anchors (748 each total) needed to be replaced with zinc-plated barrel anchors to correct the issue and prevent future failure of the same kind.
The owner approved our proposal and we utilized a system we developed to re-tighten the existing cables and to remove and replace the existing barrel anchors. For additional corrosion protection, we coated the cable ends with cold spray galvanizing, installed butyl rubber covers over the barrel anchors, and caulked the cable entry area into the anchor columns.