ballast as a part of the railway system plays an important role in the operation of the railways and also has a great impact on repair and maintenance activities. hence most of the repair and maintenance activities in traditional railway systems are due to the defections in the ballast layer and therefore most of the maintenance budget is spent on repairing these defects. these repair and maint...

Preventive maintenance is a planned activity to keep the manufacturing facilities in good condition. However, because of limited time and resources, not all the system components can be repaired/replaced during the planned opportunity. When the system is under maintenance, it is very conservative to take the maintenance decision on the components because of limited available time and resources,...

The chloride corrosion of reinforcing steel in reinforced concrete (RC) structures is a significant reason for premature deterioration and failure of RC structures in aggressive environments such as Persian Gulf region. This is one of the most important sources of engineering and economic problems in developed countries. So, the repair and maintenance of RC structures exposed to corrosive envir...

the national bridge stock of iran consists of about 330,000 bridges, of which around 50% are older than 30 years. since 2010, iran road maintenance & transportation organization has started implementing a comprehensive bridge management system in order to manage this aged stock efficiently. to predict future conditions of bridge stock, a heuristic numerical method is presented. this methodology...

Earth pressure balance tunnel boring machines (EPB-TBMs) are favorably applied in urban tunneling projects. Despite their numerous advantages, considerable delays and high maintenance cost are the main disadvantages these machines suffer from. Reliability, availability, and maintainability (RAM) analysis is a practical technique that uses failure and repair dataset obtained over a reasonable ti...

This paper considers replacement polices for an extended cumulative damage model with minimal maintenance at each shock and minimal repair at failure: A system is replaced at time T or at shock number N , and undergoes maintenance or repair between replacements. The expected cost rate is obtained and each optimal T ∗ and N∗ to minimize the cost rate is discussed. It is shown that this model wou...

Nacrtak A sample of 44 professional chainsaws was used to determine service life and maintenance cost for this type of equipment. Data were sourced from a large workshop, catering for regional forest crews in north western Italy. Chainsaw service life exceeded 3000 hours, and spread over a period of 6 to 9 years. Under these conditions, maintenance cost averaged 820 €, or about 120 % of the inv...

The present paper discusses the development of a Markov model for performance evaluation of coal handling unit of a thermal power plant using probabilistic approach. Coal handling unit ensures proper supply of coal for sound functioning of thermal Power Plant. In present paper, the coal handling unit consists of two subsystems with two possible states i.e. working and failed. Failure and repair...