Field Testing of Highway Sign Support Structures

Abstract

The results of field tests for two monotube highway sign support structures with spans of 60 and 100 ft are presented. The intent of the study was to compare field measurements with previously conducted analytical results, including the possibility of resonance due to vortex shedding. Wind speeds of up to 23.2 mph were recorded during the tests. Although the analytical studies predicted resonance tendencies at several lower wind speeds, this did not take place during the field tests due to the inherent damping of the structures. Measured stresses were analyzed statistically to account for the cyclic nature of the loads, to assure a high level of confidence in the maximum stress levels. There was good correlation between computed and measured stresses, all of which were found to be well below allowable values. The adequacy of previous design recommendations was verified.