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Volume Title: ICASGE2023

DOI: ICASGE-STL

¹Abdelrahman Emad Mohamed ; ²Ahmed Shamel Fahmy; ²Yasser Abdelmaksoud Elzeni; Abdelrahman Emad Mohamed; Ahmed Shamel Fahmy; Yasser Abdelmaksoud Elzeni

¹Structural Engineering department, faculty of Engineering, Alexandria university

²Structural Engineering department, Faculty of Engineering, Alexandria University

The Egyptian government has launched a plan to develop national railways as part of its current vision to modernize Egypt's road network. This plan includes a significant increase in train speeds on the lines. As a result of these high velocities, lateral vibrations in railway bridges over the service limits are expected. This possibility rises when the frequency of these vibrations is close to the natural frequency of the structure, which causes resonance phenomenon and amplifies the bridge's dynamic responses. This study presents two solutions to deal with these tremors and avoid their risks. The first proposal is based on using fluid viscous dampers to raise the damping coefficient of the bridge. Consequently, it becomes capable of absorbing most of the energy generated by the vibrations. While the other is grounded on replacing the existing supports with laminated rubber bearings. They can change the fundamental period away from the loads' period and thus the energy transferred to the structure is reduced significantly. To test the effectiveness of these two strategies, this research studies two existing Egyptian steel railway bridges with various structural systems. Three-dimensional finite element models of bridges in their current form have been carried out on three train loads and at increased speeds. Then, these models have been amended by incorporating the appropriate retrofitting system for each case and comparing the results of this analysis with the previous results. The proposed systems showed a considerable ability to control the dynamic behavior of the bridges under different study conditions.

High-speed railway bridge; steel; Dynamic behavior; Resonance phenomenon; Fluid viscous damper; Laminated rubber bearing; SAP2000

Steel Structures (STL)