Fatigue Tests of Welded Connections in Cantilevered Steel Sign Structures

Hyoung-Bo Sim and Chia-Ming Uang
University of California San Diego for the International Sign Association
October 2011



Summary:

Freestanding “high-rise” signs of 50 feet or more are an essential tool for many businesses seeking to market their locations to customers, and are among the various types of products designed, manufactured, supplied and used by the 2,200 members of the International Sign Association (ISA). A common design known as a “telescoping” steel column is widely used for freestanding signs that reach heights of 50 feet or more. Tens of thousands of these signs are safely in use along the nation’s interstates and major highways.

Through the ISA Technology and Research Committee, the Association became aware of concerns about a handful of these signs falling in recent years due to unknown causes. There was little data on these incidents, and as a result, conflicting theories as to possible causes. As part of its ongoing commitment to promoting the highest standards of quality and safety, ISA decided to commission an independent engineering analysis at the University of California San Diego (UCSD) to help shed more light on the issue.