International Journal of Construction Engineering and Management 2012, 1(1): 1-5 DOI: 10.5923/j.ijcem.20120101.01 Failures of Railway Concrete Sleepers During Service Life Jabbar-Ali Zakeri * , Farshad Hashemi Rezvani School of Railway Engineering, Iran University of Science & Technology, Tehran, Narmak, P. O. box 16846 – 13114, Iran Abstract Sleeper, after rail, is the most important component of track superstructure in conventional track. Keeping track geometry, bearing loads acted from rail and transferring to the ballast is the main duty of sleeper. Their quality condi- tions have considerable influence on geometry quality. Moreover, track maintenance costs affected by this element due to their higher number. For this, in order to reduce operation & maintenance volume and, in the other hand, for more recogni- tion of B70 sleepers used in Iranian Railways, some studies and field investigations carried out on concrete sleepers and its results expressed as categorization of concrete sleeper failures. This paper, evaluates effective factors and the reasons of their creation, while considering failures and conventional defects during sleeper service life (including production stage, transportation, construction and operation), and proposed some approaches for their reduction. Keywords Concrete Sleepers Construction, Sleeper Defects, Sleeper Failure 1. Introduction Railway sleepers are the main structural elements of railway track. As well as pressure distribution and load transfer to the underlying layers, railway sleepers are in duty to maintain track gauge, grantee lateral stability of the track and contribute in better geometrical conditions of the track[4,10]. Vertical, lateral and axial forces are applied to rail sleepers. These forces should be transferred to the un- derlying ballast layer within the admissible stress range with minimum disturbance of track quality and permanent de- formation. In fact, no comprehensive approach is existed when dealing with sleeper pressure and load transfer mechanism of the track structure,[2, 12]. Grassie[2] has studied the effect of unsupported sleepers in increasing imposed forces on adjacent sleepers and Kerr[5] has described the effects of support hardness changes with sleeper type change (wooden to concrete). Gustavson[8] has also studied static & dynamic behavior of the sleeper. In these studies increase of imposed forces on sleeper due to existing of defect in superstructure have been mostly dealt with. This paper took a glance look on concrete sleepers used in Iranian Railways and collected& categorized all defects, appeared in them, in different stages including production, coupling (track panel), transportation, installation and maintenance. In addition to categorization of concrete sleeper defects as well as deterioration, causes of the defects were also rooted and stated proportionate to their type. The first step to ana- lyse a sleeper is to diagnose appropriate distribution of * Corresponding author: Zakeri@ iust.ac.ir (Jabbar-Ali Zakeri) Published online at http://journal.sapub.org/ijcem Copyright © 2012 Scientific & Academic Publishing. All Rights Reserved contact stress between sleeper and ballast and its changes to the time. In real conditions in railway superstructure it is very difficult to predict correct distribution of contact stress on a sleeper[6]. There are various assumptions concerning contact stress distribution between sleeper and ballast[1] as well as bend- ing moment diagrams of a sleeper which are show in figure (1). 2. Methodology of Research B70 and B58 with Vossloh and Pandrol type fastenings are type of concrete sleepers used in Iranian Railways. B70 sleepers are used with rails UIC 60 and sleepers B58 with rails U33 (only with Vossloh clips) .To recognize main de- fects of concrete sleepers , life cycle defects of sleepers were primarily categorized as follow[3]: 1. Deteriorations during manufacture and coupling (track panelling) 2. Deterioration during transportation and installation 3. Deteriorations during use. Data collection for deterioration during production and coupling (panelling) carried out by optical inspection from plants producing concrete sleepers in Karaj and Andimeshk and analysing quality control reports, asking opinion of production experts. In this survey 1000 unusable defected sleepers in producing plant studied and their defects de- tected. Recognizing deteriorations during transportation and in- stallation were also carried out through defected sleepers study in track laying workshops and analysing QC reports. Deteriorations in operation time could be detected and categorized due to existing of monthly reports of supervising on track maintenance by supervising experts.