انتخاب روش هاي نگهداري پيشگيرانه به كمك روش AHP

Select preventive maintenance treatments using AHP

به منظور نگهداري و مديريت بهينه روسازي ها، لازم است علاوه بر روش هاي ترميم و نگهداري موجود، روش هاي جديد نيز شناخته و به كار برده شوند. روش هاي نگهداري پيشگيرانه با هدف كاهش نرخ خرابي روسازي و بهبود سطح روسازي ها به كار مي روند. اين روش ها زماني موثر مي باشند كه بر روي روسازي هاي مناسب از لحاظ سازه اي اجرا شوند، بنابراين انتخاب نوع روش نگهداري پيشگيرانه بهينه مشكل مي باشد. علاوه بر اين، فاكتورهاي موثر زياد در انتخاب روش نگهداري پيشگيرانه مناسب، براين مشكلات مي افزايد. شناخت اين فاكتورها و اين كه هر روش نگهداري پيشگيرانه چه تاثيري روي اين فاكتورها دارد در انتخاب مناسب روش نگهداري به مديران روسازي كمك زيادي مي كند. دراين مقاله، پس از شناسايي اين فاكتورها، به ارايه مدل هايي براي انتخاب روش نگهداري پيشگيرانه مناسب مي‌پردازيم. با توجه به محدوديت هايي كه كشور در زمينه تجهيزات اندازه‌گيري اين پارامترها با آن مواجه است، روش هايي براي محاسبه ساده اين پارامترها ارايه شده است. در پايان ميزان اهميت هريك از اين فاكتورها با انجام فرآيند تحليل سلسله مراتبي بر روي نظركارشناسان تعيين و مدل هايي براي انتخاب مناسب ترين روش نگهداري پيشگيرانه ارايه خواهد شد.

Necessary funds to maintain the pavements in the existing condition level is more than the budget allocated to them; and it is clear that highway agencies can’t continue to operate with traditional maintenance approaches because with this approaches and due to lack of funding, pavement conditions are gradually deteriorate. So agencies must focus on spending their money on maintenance and increasing efficiency of this money. One of the most effective treatments to optimize maintenance and management of pavement, is Preventive Maintenance (PM) treatment which is the periodic application of relatively inexpensive pavement treatments to an existing roadway system. A pavement PM treatment is an action that corrects minor defects, future deterioration, and maintains or improves the functional performance of a highway pavement without substantially increasing its structural capacity. It is well understood that applying appropriate PM treatments at the right time extends the service life of pavements. With demonstrating that PM is cost-effective for roads, agencies must abandon the practice of project selection using the “worst first” criterion and moving towards pavement preservation. “worst first” strategy means the policy of spending all agency monies to repair the poorest roads first but pavement preservation should be carried out at early stage of the pavement life while it is still in good conditions. but These treatments can be effective when the pavement has no structural distress, so choose of optimum PM treatment is difficult. In addition, choose of optimum PM treatment is dependent on many factors that makes choosing more difficult, so in this paper seven factors have been identified that effective in selecting the best PM treatment . One of the problems to agencies considering the implementation of PM treatments is lack of experience about these treatments; so determining weight of factors for agencies is difficult. to resolve this problem, experts experience of other agencies is applied and Analytic hierarchy process (AHP), that is one of the MCDM methods, is used to quantify experiences and determine weight of factors. The objective of this study is to develop models for the selection of the most appropriate PM treatment. for this purpose, a composite index with Multiple Criteria Decision Making (MCDM) methods have been used. This composite index considers several factors that affect for selection of the most appropriate PM treatments. knowing the fact that how PM treatments affect these factors, can significantly help managers to select the best treatment; so Each of these factors must have a specific weight of importance. In this paper, seven factors (roughness, skid resistance, cracking, rutting, traffic, cost and risk) have been identified. Due to lack of measuring devices, a simple calculation method for these factors has been presented. Some of these factors used in selecting PM treatment have very high absolute values, such as cost. Using these absolute values will overpower other factors such as roughness values. Therefore, a procedure of normalizing all factors was followed on this paper. One of the problems to agencies considering the implementation of PM treatments is lack of experience about these treatments; so determining weight of factors for agencies is difficult. to resolve this problem, experts experience of other agencies is applied and Analytic hierarchy process (AHP), that is one of the MCDM methods, is used to quantify experiences and determine weight of factors. After that the weight of these factors have been identified, models for selecting the best PM treatment have been presented. To build these models, Ranking method based on a composite index is used. Finally, models for selecting the most appropriate PM treatment have been presented