明桥面轨枕板式轨道典型损伤影响规律研究OA

[Objective]To investigate typical damage problems occurring in the sleeper slab track structure on the open deck of steel truss girders during long-term service,including bolt loosening,concrete spalling in limiting steel tubes,separation,and extrusion of elastic buffer layers.[Methods]Based on the elastoplastic damage theory of reinforced concrete structures,a refined nonlinear finite element analysis model capable of characterizing different damage characteristics of sleeper slab track was established.The influence of different damage levels on the mechanical characteristics of the track system was investigated.Recommended values for track maintenance and repair were proposed to improve track service safety and durability.[Results]The results indicated that when high-strength connecting bolts were loose,no significant tensile damage occurred in the sleeper slab track,and the track structural system,jointly restrained by the connecting bolts and concrete-filled steel tubes,had a high safety margin.The stresses of concrete inside the limiting steel tubes and the vertical displacement of the sleeper slab increased nonlinearly as the connecting-bolt torque decreased.Considering the long-term durability of the track structure,a bolt torque of no less than 350 N·m was recommended,and loosened bolts should be promptly retightened.Deterioration and spalling of concrete inside the limiting steel tubes aggravated the stress state of the self-compacting concrete layer and caused damage at the connection with the longitudinal girder.Timely maintenance and repair were recommended when the spalling depth exceeded 50 mm.Separation of the rubber elastic buffer layer reduced the restraining capacity of the limiting steel tubes,whereas its extrusion caused tensile damage at the bottom of the limiting holes and on the inner side of the self-compacting concrete.Timely remediation was recommended when the separation exceeded 2 mm or the extrusion height exceeded 50 mm.[Conclusion]The methods and findings can provide guidance and a reference for similar studies.