Selected Bearing Problems of Old Railway Bridges Located On Mining Areas in Poland

Abstract

In this article are discussed bearing problems of old railway bridges located on mining areas in Poland. The problem is important because the old railway bridges in the areas of active mining exploitation are still in use, but often lack of money for their replacement or major reconstruction. Railway traffic is still underway after these objects, but the requirements for increasing the speed of rolling stock are bumped up. The article applies to bridge objects, which have the static scheme of the freely supported beam, which is universally used, and it is a structural solution. The article describes how mining exploitation affects bridge bearings and the conditions that bearings should fulfil on mining areas. A short review of Polish technical solutions and Polish literature information’s on bearings of railway bridges in mining areas is made, it may be valuable for people dealing with similar problems in other countries. Attention is taken to the features that differ the bridge objects from cubature structures in the context of transferring mining influences, e.g. multi-solid of bridges and elevation of their main structural part (spans) above the ground. The general principles of ensuring kinematic freedom and selection of bearings are discussed. Typical damages and threats to the safety of the rail traffic (e.g. breaking the permanent bearing, blocking the bearing, cutting the head of the pillar) triggered by mining area deformations are pointed out. Author discusses the significant influence of bearings on the resistance of railway objects to mining deformations of the area. The article also draws attention to the necessity of frequent monitoring of bearing condition due to the possibility of sudden damage. Examples of Polish experiences are given, i.e. working SHM (Structural Health Monitoring) system is described. Safe maintenance of the object on the mining area requires a combination of knowledge from the bridge manager and mine and data from automatic monitoring systems, geodetic measurements, technical condition assessments - it indicates the need for proper organization of the process associated with acquisition, use and information flows, e.g. according to standards included in the BIM method (Building Information Modelling).