IABSE Task Group 3.1 Benchmark Results. Part 2: Numerical Analysis of a Three-Degree-of-Freedom Bridge Deck Section Based on Experimental Aerodynamics

IABSE Task Group 3.1 has the mandate to define reference results for the validation of methodologies and programs used to study both stability and buffeting responses of long-span bridges. To this end, the working group set up a benchmark procedure consisting of several steps with increasing complexity to define reference results useful for this validation. The simplest step (1.1a) was presented in Part 1. In this paper (Part 2), the contributions and reference results of the second sub-step (1.1c) are discussed. It consists of the simulation of the aeroelastic response of a three-degree-of-freedom bridge deck section forced by turbulent wind, using experimental aerodynamic coefficients measured in a wind tunnel. The increase in complexity, compared to the previous step, involves the experimental definition of unsteady force coefficients that are defined in a limited range of reduced velocities, and inclusion of the lateral motion and horizontal turbulent wind velocity components. Comparison of the different outputs, obtained by Task Group 3.1 participants with the same input data, is presented, revealing differences that are not always negligible. Moreover, the increase in complexity of the test case results in larger spreads of the results compared to the fully analytical case, analysed in Part 1.

国际桥梁与结构工程协会（IABSE）第3.1工作组的职责是制定基准结果，用于验证研究大跨度桥梁稳定性与抖振响应的方法与程序。为此，该工作组构建了一套基准流程，包含复杂度逐级提升的多个步骤，以生成适用于该验证工作的基准结果。第一部分已介绍其中最简单的步骤（1.1a）。本文（第二部分）将探讨第二子步骤（1.1c）的研究内容与基准结果。该子步骤基于风洞实测的气动系数，模拟湍流风激励下三自由度桥面节段的气动弹性响应。相较于前一步骤，本次复杂度的提升体现在两点：一是实验测定了有限折减速度范围内的非定常力系数；二是纳入了横向运动与水平湍流风速分量。本文呈现了IABSE第3.1工作组各参与者采用相同输入数据得到的不同输出结果的对比，结果显示部分差异不容忽视。此外，相较于第一部分分析的全解析案例，该测试案例的复杂度提升导致结果离散度更大。