Masoud Ghrbani - MSc student of Construction Engineering and Management, Department of Civil Engineering, College of Civil, Ahvaz Branch, Islamic Azad University, ahvaz, Iran
Jamshid Salahshour - Assistant professor at the Faculty of Technology and Engineering, Department of Civil Engineering, College of Civil, Shushtar Branch, Islamic Azad University ,Shushtar, Iran

The nature of repair projects entails many potential factors including complexity, dispersion, and emergency which create changes in work. Such changes can alter direct costs for the contractor and influence project time by creating pauses, delays and expeditions in plans and methods of doing the job. Since Iranian public companies, use contractor's services to repair and maintain buildings, there is a need to have a projects management system by considering required processes for comprehensive assessment of claims with the goal of increasing quality, reducing repair time and appropriate optimization of costs. Repair projects in Iranian public companies were studied. A four-step method of analysis was used. In the first step, the characteristics and conditions of repair projects were investigated. In the second step, frequency measurement method, probability of changing into difference and gradation of claims based on their importance were presented by recognizing factors and root causes which of transforming these factors to differences in order to carry out a qualitative assessment of such projects. In the third step, some tasks such as specifying the cost effect of factors, investigating contract rates and how to change them, identifying methods affected by plan and time, removing delays in the repair plan, recognizing causes and methods, discovering the amount of time saved, using costs differences in the updated plan and contractors' status reports, were carried out as appropriate techniques to analyze the effect of factors. In the fourth step, the expected cost of the project was compared to the real cost and a comparison was made between a time span of the project under normal conditions and another time span of the same project influenced by delay, in order to perform a quantitative assessment of the claims. In the end, the methods which were used in the study are presented as well as the use of price details and contractor's primary rates, primary schedules, and detailed schedules prepared for the process of carrying out the project are suggested as ways to calculate the altered cost and time .

Repair and maintenance of public companies' buildings, Comprehensive assessment of claim, Cost optimization, Changes in repair projects