Offer preparation has always been a specific part of a building process which has significant impact on company business. Due to the fact that income greatly depends on offer’s precision and the balance between planned costs, both direct and overheads, and wished profit, it is necessary to prepare a precise offer within required time and available resources which are always insufficient. The paper presents a research of precision that can be achieved while using artificial intelligence for estimation of cost and duration in construction projects. Both artificial neural networks (ANNs) and support vector machines (SVM) are analysed and compared. The best SVM has shown higher precision, when estimating costs, with mean absolute percentage error (MAPE) of 7.06% compared to the most precise ANNs which has achieved precision of 25.38%. Estimation of works duration has proved to be more difficult. The best MAPEs were 22.77% and 26.26% for SVM and ANN, respectively.

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Before joining the European Union, Serbia faces a big task related to the treatment and purification of wastewater. The capital of Serbia, Belgrade, and some larger cities do not have wastewater treatment plants. Although there are no plants in larger cities in Serbia, they still exist on the territory of the state itself. However, either they are not in good condition, or they do not work with the projected capacity or they do not work at all. This paper presents the model for risks quantification for the planning and design processes of wastewater treatment plants in which the risks are divided into 6 categories: legal, financial and economic, logistics, environmental protection, management and design risks. 37 risks have been defined, analyzed and evaluated by the experts participating in the Delphi method. Experts in various fields dealing with the planning, design or construction of wastewater treatment plants were selected to assess the risks through 2 rounds of Delphi methods and reach the consensus on major risks. By using statistical methods, it is determined that the experts reached the consensus after which each risk received its own relative weighting coefficient. Risk model has been initially verified by experts from Delphi team on two projects during construction phase. This model is important in the initial phases of the project, when the investor starts the project, as well as in the design phases.

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Preliminary notesThe paper considers the problem of selecting the most appropriate variation for the pipeline route Beloševac -Divci within the Kolubara regional water supply system (Serbia). Variations are evaluated according to five criteria, three of which have an economic character. The problem of selecting the optimal variant for the pipeline route is solved using the multi-criteria analysis by applying the PROMETHEE method and the implementation into the software package Visual PROMETHEE 1.4. The PROMETHEE method has proved to be applicable and suitable in solving practical problems related to civil engineering, in the phase of the final decision-making in the area of construction planning. The application of multi-criteria evaluation methodology, provided in this paper, proposes the variant with the minimal construction costs. Keywords: criteria; multi-criteria analysis; pipeline routes; PROMETHEE method; variations Višekriterijska analiza varijantnih rješenja trase cjevovoda primjenom metode PROMETHEEPrethodno priopćenje U radu je razmatran problem izbora najpovoljnije varijante trase cjevovoda Beloševac -Divci u okviru Kolubarskog regionalnog sustava vodosnabdjevanja (Srbija). Varijante su vrednovane na osnovu pet kriterija, od kojih su tri kriterija ekonomskog karaktera. Problem izbora optimalne varijante trase cjevovoda riješen je višekriterijskom analizom primjenom metode PROMETHEE implementacijom u softversko rješenje Visual PROMETHEE1.4. Metoda PROMETHEE se pokazala primjenjivom i pogodnom u praktičnim problemima građevinskog inženjerstva, u fazi konačnog odlučivanja u području planiranja izgradnje. Primjenom metodologije višekriterijskog vrednovanja, danom u ovom radu, korisniku se predlaže varijanta s minimalnim troškovima izgradnje.