Methods of Calculating Wind Loads on Long-Span Girder Bridges with Tall Piers and Comparison of Values

Abstract

Calculating wind resistance is an important process in the design of highway bridges. The current codes of many countries include different rules and formulas regarding the calculation of wind resistance. In this paper, the transverse-direction wind loads on long-span girder bridges with tall piers were calculated using six codes from different countries under various terrain, pier height, and girder length conditions. The pier-bottom shear force and moment results of transverse wind loads calculated using these six codes were compared with those obtained using the buffeting frequency domain method. Results showed that, in Class B terrain, wind load results predicated on China’s 2004 general codes for the design of highway bridges and culverts, China’s 2004 wind-resistant design specifications for highway bridges, Japan’s 2007 wind-resistant design manual for highway bridges, and Part 2 of Britain’s 2006 steel, concrete, and composite bridge specifications for loads resembled each other closely. Some difference was found to exist among Classes A, C, and D terrain. The 2007 AASHTO LRFD bridge design specifications and China’s 2001 load codes for the design of building structures showed significant differences from the other four codes on all kinds of terrain. The applicability of the wind load rules in the AASHTO LRFD bridge design specifications to long-span girder bridges with tall piers merits further discussion. China’s wind load calculations of load code for the design of building structures mainly depended on the empirical parameters of architectural structures with large dimensions, and had limited applicability to bridge structures. For long-span girder bridges with tall piers, such as bridges with span length-to-width or -depth ratios exceeding 30, or pier height-to-transverse-width ratio exceeding 10.7, the wind load calculated using these codes was generally underestimated due to the neglect of the effects of aeroelastic forces, which must be taken into account in the design of these kinds of bridges.