A Comparative Assessment of Aerodynamic Models for Buffeting and Flutter of Long-Span Bridges  

作　　者：Igor Kavrakov Guido Morgenthal 

机构地区：[1]Research Training Group 1462, Bauhaus-University Weimar, Weimar 99423, Germany [2]Chair of Modeling and Simulation of Structures, Bauhaus-University Weimar, Weimar 99423, Germany

出　　处：《Engineering》2017年第6期823-838,共16页工程（英文）

基　　金：supported by the German Research Foundation (DFG) via Research Training Group ‘‘Evaluation of Coupled Numerical and Experimental Partial Models in Structural Engineering (GRK 1462);"

摘　　要：Wind-induced vibrations commonly represent the leading criterion in the design of long-span bridges. The aerodynamic forces in bridge aerodynamics are mainly based on the quasi-steady and linear unsteady theory. This paper aims to investigate different formulations of self-excited and buffeting forces in the time domain by comparing the dynamic response of a multi-span cable-stayed bridge during the critical erection condition. The bridge is selected to represent a typical reference object with a bluff con- crete box girder for large river crossings. The models are viewed from a perspective of model complexity, comparing the influence of the aerodynamic properties implied in the aerodynamic models, such as aerodynamic damping and stiffness, fluid memory in the buffeting and self-excited forces, aerodynamic nonlinearity, and aerodynamic coupling on the bridge response. The selected models are studied for a windspeed range that is typical for the construction stage for two levels of turbulence intensity. Furthermore, a simplified method for the computation of buffeting forces including the aerodynamic admittance is presented, in which rational approximation is avoided. The critical flutter velocities are also compared for the selected models under laminar flow.风致振动通常代表了大跨度桥梁设计的主要标准。桥梁空气动力学中的气动力主要基于准定常和线性非定常理论。本文旨在通过比较多跨斜拉桥在临界架设条件下的动力响应,进而推演出不同时域自激力与抖振力的表达式。这类混凝土箱梁桥是用于大型河流交叉口的典型参考对象。本文从模型复杂性的角度进行分析,对比了气动模型中隐含的气动参数,如气动阻尼和气动刚度、抖振力和自激力中的流体记忆、气动非线性和气动耦合等对桥梁响应的影响。选定的模型用于研究一定风速范围内的结果,该风速范围对于考虑两种湍流度情况的施工过程是典型范围。此外,还提出了一种计算包括气动导纳在内的抖振力的简化方法,避免了有理逼近。在层流流动下,也将对根据所选模型计算得到的临界颤振风速进行对比。

关 键 词：BUFFETING FlutterLong-span bridges Bridge aerodynamics Bridge aeroelasticity Erection stage 

分 类 号：N[自然科学总论]