نوع مقاله : مقاله پژوهشی
عنوان مقاله English
نویسندگان English
A significant portion of Iran’s railway network is located on old bridges, particularly masonry bridges. Given the age and historical importance of these bridges, their preservation and maintenance are essential. In this study, numerical modeling of the Karaj masonry bridge and the passing train was conducted to investigate the effects of different track systems, including ballasted, concrete slab, and ladder tracks, on train–bridge interaction under different train speeds and axle loads. Based on the available material strength tests as well as static and dynamic field tests conducted on the bridge during the passage of different trains at various operating speeds, a detailed numerical model of the bridge–train system was first developed and validated. After confirming the reliability of the model, sensitivity analyses were performed for each track system to investigate the effects of axle load and train speed on the structural response. The results showed that increasing the axle load increased the vertical displacement and acceleration in all three track systems. The maximum vertical displacement at the center of the first span was 1.119, 0.86, and 0.81 mm for the ballasted, ladder, and concrete slab tracks, respectively. The corresponding maximum vertical accelerations at this location were 0.2687, 0.1864, and 0.1672 m/s², respectively. Overall, the concrete slab track produced the lowest vertical displacement and acceleration. The speed range corresponding to the maximum dynamic response varied between 90 and 120 km/h, depending on the track system and the response parameter considered.
کلیدواژهها English
