Optimizacija sistema upravljanja mostovima

Abstract

The doctoral dissertation deals with an extremely complex and very topical issue of bridge management. Basic imperatives of correct formation and design of contemporary population of bridge structures are safety and serviceability as fundamental properties of bridges; it is tended to retain serviceability in certain time period (service life) providing durability and reliability. The task of a builder is to conceive, design and build bridges in such a way that they can withstand all the impacts they will be exposed to. Bridge structures must be reliable and serviceable for an optimal number of years, so for that reason, all requirements concerning bearing capacity, serviceability and durability should exceed the minimum permissible level. It is impossible to achieve absolute safety, infinite durability or perfect serviceability, but we must strive to an optimum condition. On the other hand, there is a large number of bridges around the world, serving different functions, which were built in various environments ,various times, from various materials, of various forms, systems, spans and dimensions. During service, due to permanent material fatigue and effects of other diverse parameters and processes, damage and progressive deterioration of bridge structures are inevitable, which has a negative effects on bearing capacity, serviceability and durability of bridge structures, and therefore on their reliability and safety. However, a prolonged downtime of bridges because of repairs, reconstruction or replacement can cause very inconvenient disruptions of road and railway traffic. Preventive maintenance of bridges, as an optimal solution from the technical, organizational and economic aspect was not paid due attention, especially in our country. A permanent increase of bridge structure damage was observed, with the enormous decrease of bearing capacity and safety of bridges, and even some very important bridges in the world collapsed. Such a problem required an efficient bridge management system which will yield sensible and reasonable decisions regarding allotment of finances in the conditions of very restricted funds and budgets. In this context, in the doctoral dissertation, an analysis of the global approach to the bridge management issue and importance of its implementation was conducted, along with the analysis of structures of most of bridge management systems in the world, as well as a detailed analysis of impacts of relevant parameters on the management efficiency. By comparing various criteria for determining priority in the world, both at the individual level and at the level of a section or network as a whole, certain conclusions and propositions for an adequate model of the iv bridge management system in our conditions were created. The proposition of optimization of criteria for evaluation of priorities in the bridge management system of Serbia, removed the observed deficiencies and improved efficiency in making of the list of order of priorities of bridge structures. The potentials of the newly developed, proposed criterion of priority evaluation were verified on concrete examples. Analysis of bridge structures on the city traffic routes of Nis formulated practical rules and defined clear guidelines for necessary further bridge management activities. A special attention was paid to the potential of implementation of the Markov chain mathematical model for bridge structure deterioration prediction, using the results of realized and own theoretical and practical research. All short-term and long-term consequences of postponing or abstaining from necessary maintenance measures regarding bridge structures on the traffic routes of Nis were assessed. The potential of integration of bridge management system into the planning, designing, construction and service processes of transportation infrastructure was realized. The obtained results of the scientific research work in the doctoral dissertation increase the efficiency of planning management and of coordination of relevant activities. The ultimate realized goal of the doctoral dissertation is improvement of the total condition of the bridges and introduction of contemporary trends in the field of management of these structures, based on the relevant indicators of the mathematical apparatus in terms of emergence of potential damage and failure of bridge structures, with an aim to find a long-term solution, as a combination of the optimum condition and optimum repair measures.