“Is the tower safe?” is a terrifying question. Tower inspectors and nearby residents want to know the large construction they are working on or living near is safe. Not only does a collapse affect the safety of those nearby, it also has ramifications during zoning hearings and the approval process for new towers. A tower fall can significantly restrict possible sites, lengthen the permitting process, or make another tower financially unfeasible. AnchorGuard wants to ease the burden on tower companies by proving anchor protection and corrosion monitoring.
The danger of unseen corrosion of guy tower anchors is tremendous, says Craig Snyder with Sioux Falls Towers. According to Snyder, “If an anchor fails, the tower is almost certain to fail as well.” He explained further, “If climbers are on the tower during the failure, it would be catastrophic.” Visual inspections of the steel shaft just below the surface may or may not reveal anchor issues. “Experience has shown that just because you see some rust at the surface doesn’t mean the shaft is necessarily structurally impaired, and just because you see no rust at the surface doesn’t mean there isn’t significant rust below grade.”
AnchorGuard can perform two separate inspections to provide the most accurate analysis for their customers. A surface inspection reaches two feet below the surface, to determine if any corrosion is present on the anchor shaft. A laboratory test is performed on the soil to ascertain the presence of salts, water, and other elements that could damage the shaft. An in-depth subsurface inspection is also available, which will test the entire length of the anchor shaft, down to its concrete foundation.
Snyder directs those worried about corrosion protection to the AnchorGuard website. It explains there are a variety of factors indicative of dangerous corrosion:
Fortunately, AnchorGuard also provides corrosion control systems. These systems are designed based on the size of the tower in question. Each one provides and monitors cathodic protection on three anchors. Sacrificial anodes are coupled with a permanent reference cell and test head at each anchor, providing ongoing monitoring at each site to safely maintain the integrity of the structure, especially while maintenance is performed.
By Braden Hall, Inside Towers
April 13, 2017