Reinforcement Technology on Short-span Bridges for Heavy-haul Railway Based on the Method of Adding Supports

Research purposes:The short−span bridges are an important component and weak link of heavy−haul railway transportation. The service performance of short−span bridges is easily affected by axle load of freight train, making it difficult to meet the needs of capacity expansion of heavy−haul railways. Taking the common short−span bridge with a span of 12.0 m as an example, a simple reinforcement method for short−span bridges by adding vertical supports to change the structural system is proposed to improve the bearing capacity. Combined with numerical simulation and actual bridge test, the influence analysis of reinforcement parameters and the study of static and dynamic adaptability before and after reinforcement of short−span bridges are carried out, and reasonable reinforcement parameters are determined. Research conclusions: (1) The basic principle of adding support reinforcement method is to add vertical supports on both sides of the original supports of short−span bridges. By reducing the bridge span and changing the bridge system structure, the internal stress of the bridge is reduced, thereby improving the bearing capacity and service conditions. (2) The reasonable value for adding vertical support stiffness is 50% of the original support stiffness, and the reinforcement distance should be installed at the edge of the pier cap. The longitudinal width of the added support should be consistent with the original support. (3) After adding support reinforcement, the static and dynamic performance indicators of the bridge structure, such as mid span deflection, lateral vibration acceleration and vertical amplitude, as well as vertical displacement of the support, have significantly improved, with a reduction of more than 20%. The improvement degree of lateral amplitude and vertical acceleration of the bridge is slightly small. (4) The reinforcement method proposed in this paper can provide reference for the strengthening and maintenance of existing railway bridges. © 2024 Editorial Department of Journal of Railway Engineering Society. All rights reserved.