Comparative and sensitivity study of flutter derivatives of selected bridge deck sections, Part 1: Analysis of inter-laboratory experimental data

Aeroelastic coefficients (flutter derivatives) of bridge decks are routinely extracted from wind tunnel section model experiments for the assessment of performance against wind loading. Two distinct methods, developed over the years, are usually employed for this purpose (free or forced vibration). Even though advantages and disadvantages of each technique have been highlighted by numerous researchers, few examples of a systematic comparison of the experimental results are available in the literature. The significance of this study is related to the evaluation of an extended set of experimental data on flutter derivatives, and includes the analysis and interpretation of the differences recorded through the two methods. The motivation for this work emerged from the United States–Japan Benchmark Study on Bridge Flutter Derivatives that Iowa State University (ISU) in the United States and the Public Works Research Institute (PWRI) in Japan, initiated in 2002. Tests were designed to cover a wide range of solid cross sections, from bluff (rectangular prisms) to streamlined, in particular considering the current trend of engineers to use aerodynamically-designed girders for bridges with longer spans. In this paper, a systematic analysis and a comparison of laboratory results of flutter derivatives obtained at both institutions were performed. In a companion paper, a sensitivity study was performed to examine the implications of the perceived dissimilarities among flutter-derivative data sets on the aeroelastic instability of long-span bridges (single-mode and coupled-mode).