Experimental Fatigue Evaluation of a Gusset-Less Truss Connection

Structural performance prediction of innovative connection details requires both advanced design tools and analysis models that are verified through experimental data. For most civil structures, field or full-scale tests to failure are not feasible, therefore scale model laboratory experiments are critical to advancing the state-of-the-art for structural design. To isolate the target structural behavior for evaluation, all structural behaviors, including impact of boundary conditions and members interactions, must be controlled and accurately accounted for in the associated structural models. Data collection including installation procedure, sensors type, sampling rate and data acquisition system are critical components to any experimental or field fatigue test. Fatigue experiments often benefit from data collected at locations that are difficult, if not impossible, to instrument with traditional contact strain gauges, such as weld toes or curved members. This paper presents the experimental fatigue evaluation of a unique steel connection, including the instrumentation plan, which utilizes contact and non-contact measurements, and collected data from a high cycle fatigue experiment of a scale model specimen of a gusset-less truss bridge connection. The monitoring protocol for an experimental fatigue test setup and the evaluation of structural response measurements is developed, implemented, and tested as part of this study. This paper also presents the use of numerical modeling to supplement experimental testing, and the high-cycle fatigue testing results of the novel connection studied herein.