Wind tunnel investigations of crosswind loads for static road vehicles on wide bridge decks

Abstract

Accurately identifying the aerodynamic loads on vehicles is the fundamental issue for assessing the driving safety of vehicles on long-span bridges subjected to strong crosswinds. Thus, the aerodynamic interference of bridges with vehicles must be considered. However, very few studies have been conducted to quantify both the steady and unsteady crosswind loads for vehicles on wide bridge decks. In this paper, the mean and peak aerodynamic coefficients and aerodynamic admittance functions for three types of high-sided vehicles (medium trucks, buses, and tractor-trailers) on two wide bridge decks (a single-box girder and a twin-box girder) were determined by means of wind tunnel tests. The effects of vehicle position, wind angle of attack, and geometric shape of the deck on these aerodynamic parameters were investigated. The results show that the aerodynamic coefficients of vehicles on both bridge decks vary significantly with their lateral position. Moreover, the effect of wind angle of attack on the aerodynamic coefficients of vehicles on the leeward side of the twin-box girder is extremely substantial, as is the geometric shape of the bridge deck. However, the vehicle position, wind angle of attack, and bridge deck geometry all have little influence on the aerodynamic admittance functions of vehicles.