Reducing Conservatism in Wind Load Design: A Probabilistic Approach for Railway Bridges

Abstract

A railway bridge in Switzerland has been analyzed for wind-induced structural loads using long-term meteorological data. The Swiss standards and also the Eurocodes assume direction-independent wind pressures, leading to conservative design values. This study employs a directional wind load assessment, considering both longitudinal and transverse wind components. As a linear structure, the bridge is primarily affected by wind from a single dominant direction, offering substantial optimization potential. Using a Gumbel distribution for extreme value modeling, characteristic wind pressures were derived from a 43-year dataset. The results indicate a significant reduction in the transverse wind pressure (q_p0,char = 0.79 kN/m²) compared to the normative approach (q_p0,char = 1.3 kN/m²). Furthermore, the long-term wind data do not show an increasing trend in wind speeds over time. This refined methodology offers potential for optimizing structural design and enhancing sustainability in bridge engineering. The findings support a probabilistic approach to wind load estimation, promoting cost-effective design adaptations for existing bridges.