Improving the survivability of a railway bridge with damage to a truss members

Abstract

In the modern era, accidents and damage to individual structural elements of bridges are frequently recorded, so the issue of bridges survivability, as the ability to pass the transport load with damaged elements, is becoming more and more relevant. The timeliness is confirmed by the inclusion of new requirements for survivability testing in modern bridge design standards. The article gives a publications review in the field of survivability theory development, identifies the methods of its increase in relation to transport structures and conducts research on increasing the railway bridges survivability. The research review in the field of assessment and increase of structures survivability as applied to transport structures allowed to single out the methods of survivability increase by providing bearing capacity of structures key elements, optimisation of spatial performance of a building structure and development of special organisational measures of emergency situation exclusion. With regard to the superstructure with through main trusses of a railway bridge with a design length of 66 m, numerical methods have been used to investigate the possibilities of increasing the reliability by increasing the bearing capacity of key elements. It has been established that the positive effect of increasing the survivability by excluding the bottom chord member and struts from operation gives an increase in the bearing capacity of the bottom lateral bracing and struts, respectively. It is revealed that the most dangerous is the exclusion from operation of the upper chord truss members, and the bearing capacity increase of the key lateral bracing elements, as well as the increase of the degree of static indeterminacy of the lattice of links is ineffective. Organisational measures in case of damage and failure of the span truss element are proposed.