Effective temperature of railway concrete bridges in plateau regions based on long-term meteorological data

To determine the effective temperatures for railway concrete bridges in the Plateau region of China, this study collects meteorological data from 23 national reference stations in Xizang between 1979 and 2018. A 40-year numerical simulation of the temperature field based on these records is conducted to generate statistical samples of effective temperatures. Using the generalized Pareto distribution (GPD) model, representative values of effective temperatures corresponding to a 100-year return period are calculated, and spatial interpolation is applied to produce isotherm maps of the effective temperatures. The results indicate that the effective temperatures in most parts of Xizang exceed the values specified in current Chinese design standards, suggesting a potential underestimation of thermal effects. Moreover, the effective temperatures of concrete bridges show high sensitivity to local climatic and environmental conditions, with regional variations reaching up to 16°C for maximum and 18°C for minimum values. These findings show the necessity of incorporating local climate conditions into the detailed design of plateau bridges. The isotherm maps developed in this study provide an intuitive visualization of extreme temperature distribution with enhanced geographical resolution, offering a valuable reference for refining temperature-related provisions in Chinese bridge design codes.