Fatigue analysis of sign-support structures during transportation under road-induced excitations

Abstract

Dynamic Message Signs (DMSs) are increasingly used in highways as an effective means to communicate time-sensitive information with motorists. To ensure the long-term performance of DMSs, it is critical to ensure that the truss structures that hold them can resist not only extreme loading events, but also fatigue induced by service loads. The existing studies, however, are primarily focused on the loads that DMS-support structures experience during their service life and neglect the potential contribution of stresses induced during the transportation of them from the fabrication site to the location of installation. As a result, the potential damage that this important category of structures may sustain during transportation had remained largely unknown. To investigate this aspect, a comprehensive field test and numerical study were conducted. For field investigation, one span of a four-chord, overhead sign-support structure was instrumented to perform a short-term structural health monitoring. In addition, detailed finite element simulations were conducted to obtain an in-depth understanding of the potential modes of damage under the excitations induced by the road profile. The outcome of this study is expected to contribute to evaluating the extent of fatigue and structural vulnerability of DMS-support structures during transportation.