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This study deals with the condition examination of elementary school buildings in Primorje-Gorski Kotar County, Croatia. For schools to be functional and of high quality, adequate maintenance is mandatory. Therefore, school maintenance programs need information on the building's condition based on systematic and comprehensive assessments as a primary input. This study aims to establish a framework for assessing the condition of school buildings, based on which information can be obtained quickly and practically regarding the condition of all critical facility elements. To this end, a database on schools and their conditions was created. The conditions of school buildings in terms of damage and defects and their causes were determined. Descriptive and inferential statistical operations were performed on the collected data. A condition assessment of the buildings was performed using a questionnaire survey among the principals, based on the school buildings division model developed in this study ; the model presents building elements and a systematic visual condition rating scale. According to the available data, this is Croatia's first condition assessment on elementary school buildings. The main results show that on average, the examined schools are in good condition. Moreover, according to the results, the school building condition is most affected by dilapidation and lack of financial resources.

Construction of road structures, including highways, on the Republic of Croatia territory often suffers from the planned time and cost deviations, whereby overruns are particularly unacceptable. In terms of costs, overestimated costs can also cause problems because it is more demanding to ensure more investment money. Therefore, the main research goal is to investigate relations between realized and contracted time, also realized and contracted costs of highway construction by applying predictive modelling – linear regression and some soft computing methods. In addition, the goal is to investigate the possibility of establishing the appropriate model for estimating the duration and cost of similar projects by using simple linear regression analysis, neural networks (NNs) and support vector machine (SVM), using the software DTREG. By comparing the accuracy of the obtained models using mean absolute percentage error (MAPE) and the coefficient of determination (R2) as standard estimators of the model accuracy, the optimal models have been selected, and the possibility and conditions of their application in practice have been analyzed. Furthermore, the differences, advantages, and disadvantages in applying linear regression and soft computing methods in solving this and similar engineering problems were explored, primarily in time and cost planning.

In the second half of 2020, there was a strong increase in building material prices on world markets, which continued in 2021. Given the unstable geopolitical and epidemiological circumstances, future price fluctuations are unknown. Construction projects are sensitive to such oscillations as contracts and plans are concluded at a time when price changes cannot be predicted with certainty. Given the degree of environmental construction, maintenance projects of existing buildings are becoming increasingly important. Public-funded institution maintenance projects under regional and local self-governments are particularly at risk. Public administrators make maintenance decisions based on existing priority systems and available budgets, which are already limited and pressured due to rising material prices. To mitigate the disturbances, this paper aims to analyze fluctuations in the market of frequently used maintenance materials and provide support to public administrators, i.e., decision-makers, in the form of maintenance management recommendations, in the context of activating the price increases risk. The research consists of two parts, a review of the theoretical background and the processing of material cost data. From the available literature, insight was gained into the current way of planning, budgeting, and way of maintenance performing of public institutions in the Republic of Croatia. The problem of fluctuation in construction material prices and its impact on maintenance was recognized. Often used maintenance materials prices data were collected and analyzed, the resulting changes were graphically and numerically presented, and the problems these changes cause within the maintenance process were identified. Finally, recommendations were made to mitigate the identified disorders that public administrators will be able to apply.

Project Procurement Management is a key success factor for managing complex and challenging process of delivering construction projects. One of the important areas of Project Procurement Management is determining which project delivery method is best suited for a specific project. The selection of project delivery method may affect the overall time, cost, quality and success of the project. It is influenced by the complexity, importance and size of the project, owner’s management skills or contractor’s management capability, financial resources, time constraint, quality, resources, project roles and responsibilities, and by the impact of risk and uncertainty. Traditional approach is today’s name for Design–Bid–Build (DBB) project delivery method. The DBB method (or traditional approach) implies the sequence of separate activities (design, bid, build) and selection of the contractor only after the design phase has been completed. In Croatia, the traditional approach has been so far the most widely used project delivery method, mainly due to legal constraints. Therefore, this paper delineates project roles and responsibilities, as well as risks and opportunities, comparing the DBB method with the integrated project delivery and turnkey approaches, such as Construction Manager-At-Risk (CMR) and Design-Build (DB) methods. The aim of this paper is to highlight the potential ambiguities in Croatian legislation for the greater application of contemporary project delivery methods.

The paper provides an overview of the public educational facilities cost management in the territory of the Republic of Croatia when it comes to facility maintenance and energy consumption in the exploitation phase. Cost rationalization and appropriate measures regarding facilities maintenance and energy consumption costs are in the focus of research interest. Previous studies have shown that the costs of facilities maintenance during its lifecycle are multiple in relation to construction costs, it is, therefore, important to influence the reduction of these costs, even in the planning and design phase, thinking of the consequences in the exploitation phase. As the educational facilities cost management cover the public sector, reducing these costs and increasing their efficiency is of wider social interest. In this paper, by reviewing the literature and analyzing the financial statements of several facilities, it has been established that educational facilities cost management in the mentioned segments, is not efficient enough, therefore, it is necessary to establish and carry research to provide concrete and effective measures to rationalize these segments. A research proposal that would provide such measures is given at the end of the work.

U radu je prikazana usporedba tradicionalnog (proračunskog) modela nabave javnih i društvenih građevina s modelom javno-privatnog partnerstva (neproračunski model). Istraživanjem kojim je obuhvaćeno devet izgrađenih građevina s područja Republike Hrvatske, usporedno su analizirane javne i društvene građevine isporučene tradicionalno i po modelu JPP-a. Rezultati pokazuju veću efikasnost JPP modela u izgradnji javnih i društvenih građevina unutar planiranog proračuna i roka građenja., The comparison of the traditional (budget-funded) public building procurement model with the public private partnership (non-budget funded) model is presented in the paper. Public service buildings procured based on the traditional model and those procured according to the PPP model are compared in the scope of research involving nine buildings realized in the Republic of Croatia. The results point to greater efficiency of the PPP model in the construction of public service buildings, with regard to both cost and time of construction work., In der Abhandlung wird der Vergleich des traditionellen (Haushalts-)Modells der Beschaffung öffentlicher und sozialer Bauten mit dem Modell der öffentlich-privaten Partnerschaft (Nicht-Haushalts-Modell) dargelegt. Bei der Untersuchung, mit welcher neun errichtete Gebäude auf dem Gebiet der Republik Kroatien umfasst wurden, wurden parallel öffentliche und soziale Bauten, die auf traditionelle und nach dem ÖPP-Modell ausgeliefert wurden, analysiert. Die Ergebnisse zeigen eine höhere Effizienz bei den ÖPP-Modellen beim Bau öffentlicher und sozialer Gebäude innerhalb des geplanten Haushalts und der Baufrist.

Rad se bavi primjenom umjetnih neuronskih mreža u planiranju godišnjih operativnih troškova škola s područja Republike Hrvatske. U tu su svrhu prikupljeni podaci za 51 hrvatsku školu te razvijene tri različite umjetne neuronske mreže: višeslojni perceptron (MLP), mreža opće regresije (GRNN) i mreža s radijalno zasnovanom funkcijom (RBFNN). Softver koji se koristio za ove potrebe se naziva DTREG - Predictive Modeling Software. Usporedbom dobivenih rezultata pokazalo se da se najveća točnost procjene postiže primjenom GRNN mreže čiji je MAPE tijekom validacije 7, 97%, a koeficijent determinacije 0, 90. U ovom se slučaju GRNN mreža pokazala optimalnom za procjenu troškova. Za potrebe planiranja troškova u konkretnim slučajevima može se ispitati veći broj mrežnih modela što mogućnosti softvera dopuštaju bez većih problema. Rezultati ovog istraživanja ukazuju da GRNN daje dobre rezultate te je treba uzeti u obzir u budućim procjenama. U praksi se uvijek želi ostvariti što točniji financijski plan, pa je svaki doprinos povećanju točnosti, od značaja.

Praćenje progresa izvedbe zemljanih radova uz točnu procjenu produktivnosti građevinskih strojeva omogućuje detaljan uvid u tijek izvedbe, ranu detekciju slabe produktivnosti, kao i svih ostalih mogućih nedostataka, povratnu informaciju ispravnosti donesnih odluka te precizniji iskaz potrebnog vremena i troška aktivnosti. Ranim uočavanjem, i alarmiranjem, svih rizičnih, nepovoljnih radnji, pružene su mogućnosti za pravodobno poduzimanje odgovarajućih, korektivnih mjera i provedbu poboljšanja. Bežične tehnologije pružaju znatan potencijal za primjenu u svrhu praćenja progresa rada i procjene produktivnosti. Međutim, dosadašnja istraživanja ukazuju na nedostatke i ograničenja. Potrebna su daljnja istraživanja njihovih velikih potencijala, a moguće rješenje problematike i kompleksnosti u praćenju progresa rada i procjene produktivnosti predstavlja integracija različitih bežičnih tehnologija. Vizualne tehnologije su, pritom, neizostavno područje bežičnih tehnologija za razvoj odgovarajuće, pouzdane, vjerodostojne, brze i ekonomične metodologije za praćenje progresa izvedbe zemljanih radova uz točnu procjenu produktivnosti građevinskih strojeva.

The continuous increase of the scope of investment construction projects and their goals in environment, which abounds with many constraints and stakeholders, asks for efficient project management with adequate software support. Building Information Modelling (BIM) emerges as one such integral tool. Although it is accepted by the scientific community, there are several subjective and objective barriers in its wide application such as lack of knowledge, qualification, and awareness of necessity for BIM implementation. Using a web-based questionnaire and personal questioning, the data of students of the graduate study programs in the architecture, engineering, and civil engineering fields at four universities in Croatia (Rijeka, Zagreb, Split, and Osijek) was collected, analyzed, and compared. Results of the performed statistical analysis show that students gain knowledge and skills (CAD modelling, n-D modelling, and multi-disciplinarity of projects environment), which is a good prerequisite for BIM implementation in the future. The conducted research gives a preliminary insight into possibilities of BIM implementation into lecturing plans and programs at technical universities to become basic knowledge of the construction industry and its improvement.

There are many crucial parameters that affect the productivity of the construction machinery. Although various methods and tools exist, available estimates of productivity lack a reliable and adequate prognostic model. Wireless technologies offer considerable potential for application with the purpose of planning and control of the productivity of construction machinery. Considering the fact that there are several types of wireless technologies, each with their own specific characteristics as well as advantages and disadvantages, it is necessary to analyze the adequacy of their application for the construction project at hand and the costs associated with them in order to make the most favorable selection. The paper gives an overview of the situation regarding the research on the issue of planning and control of productivity of construction machinery by applying the following wireless technologies: Radio Frequency IDentification Technology (RFID), Global Positioning System (GPS), and On Board Instrumentation (OBI). Assessment of the actual productivity of construction machinery is necessary in order to predict the required time and cost of construction.

Radom je prikazana S-krivulja te njena uporaba unutar građevinskih projekata. S-krivulja predstavlja grafički prikaz kumulativnog rasta određenog resursa (troškovi, broj radnika, količina proizvoda itd.) u vremenu trajanja projekta. Unutar građevinskih projekata koristi se kao grafički alat upravljanja projektima. Najčešća je primjena S-krivulje koja prikazuje odnos troškovi-vrijeme. Usporedbama, praćenjem i kontrolom S-krivulja uočavaju se odstupanja od planiranih vrijednosti te voditelj projekta može na vrijeme reagirati i poduzeti određene korektivne mjere kako bi se projekt vratio u planirani okvir, odnosno kako bi se ostvarili ciljevi projekta. Rad definira S-krivulju te prikazuje njenu osnovnu uporabu u građevinarstvu, kako bi se dao pregled dijela teorijske podloge za buduća istraživanja vezana za njeno modeliranje.

The paper presents the relation between the planned duration and costs for a project of reconstructing an overage public structure to become a public facility with social purpose. The aim of the paper was development of a management model for such projects so that they could be successfully carried out in terms of cost and time. The selected example presents the methodology of time and cost relation in the project. The selected tool for connecting the mentioned project parameters is the S- curve. The S-curve is obtained through the planning process in several steps which include creation of project WBS (work breakdown structure), cost estimate and progress chart (Gantt chart). The obtained S- curve is the basis which later serves as the indicator for project performance success. Aberrations from the planned values can be detected by comparisons, monitoring and control which enables duly reaction and undertaking specific correction measures. A quick information about key trends of the project and effects of specific decisions and measures on project cost and duration is obtained. The developed model can be applied to projects of reconstructing and reallocating public structures into public facilities with social purpose with similar technical and functional characteristics such as: size of the surface, number of floors, construction type, purpose and other.

The increased use of projects and project management in almost all societal sectors has resulted in a powerful and well-established practical knowledge field that set out to provide managers with tools and methodologies for achieving project success. Public investment projects are especially success- sensitive as they are societally and sustainably oriented where the public interest is paramount. Selecting among variety of investment projects in a public administration portfolio can often be challenging because the projects are difficult to compare, and because the various interested parties view the projects in different ways. Public projects regularly deal with multiple stakeholders whose opinions can strongly influence the project therefore they must be managed with care. To implement their opinions in decision-making process towards project success, a multi- criteria methods and group decision-making can help. In order to select the best project solution, we designed the model to evaluate and rank public administration projects which is based on PROMETHEE methods. Proposed model is tested on public reconstruction project in order to provide a final rank list of several project versions of public building in the Delnice city. Such approach resulted with inclusion of qualitative and quantitative criteria with their relative importance defined by the multiple stakeholders. Proposed model contributes to higher quality and more consistent ranking of public investment projects, which is based on group consensus of all stakeholders.

Recent development of the University of Rijeka campus area affects the quality of life (QoL) of the entire city of Rijeka population, especially student population, which comprises 13% of the city’s total population. During Campus First Development Phase (2008-2011), four faculties found their place in the campus area with no student accommodation nearby. However, in the fall of 2016, during the Second Development Phase, which began in 2015, the first on-campus-accommodations will be provided to students. Technical and economic aspects are the core during investment planning and decision-making processes, while the user requirements are rarely taken into consideration from the actual end-user, resulting in superficial implementation in developing processes. The aim of this paper is to identify the most important indicators influencing the students' QoL in the city of Rijeka and to give an insight of student needs as an input for better investment planning and modelling of urban areas according to their needs. Using a web-based questionnaire as well as personal questioning, the data were collected, analyzed, and compared across four groups of variables (accommodation, faculty location, food and beverages, and out-of- curriculum activities). The conducted research gives a preliminary insight into the students' points of view, thus giving the decision-makers a necessary tool for making more student- oriented decisions in the future campus development phases as a long-term developing processes in the urban area management.

Construction time is an element of every construction contract. Thus, its prediction is of particular interest. This paper presents a construction time prediction model by using General Regression Neural Network. Key data on a total of 70 constructed buildings have been collected through field studies. Chief engineers of construction companies have been interviewed on contractual and actually incurred construction times, contractual and actual construction costs, type of facilities and construction year. General Regression Neural Network (GRNN) from predictive modelling software named DTREG, as new approach in forecasting, was used for building the predictive model to predict the real construction time. Prediction was very accurate with mean absolute percentage error, MAPE, around 2.19 which means that the error of the model is around 2.19%, the coefficient of correlation between the actual and the predicted values is very high, r = 0.99 (rounded) and the coefficient of determination which measures the global fit of the model R2 is 0.97875 (or 97.88%). This paper contributes to and can be useful for the decision process on planning the construction time in construction companies and in the construction industry in general.

Small urban areas are vulnerable to wrong strategic investment decisions due to their limited financial assets. Decision making in such environment is a complex task that requires the serious efforts of various stakeholders. Inappropriate decisions can cause catastrophic consequences and therefore they should be seen and treated as potential environmental and social disaster. In order to make small urban areas resilient of such conditions, proactive steps are first and last steps of defence. In public private partnership (PPP) projects both partners (private and public) are focused in delivering efficient and responsive services which meet public expectation. Public sector is often recognized as the most important PPP project stakeholder but one should have in mind other stakeholders as well. It is important to raise awareness of council officials and citizens of all outcomes of such investment project, and to include them into decision making process. One of the answers might be in multi-criteria methods, how opinions of public investment project stakeholders can influence the risks and projects success. Each stakeholder opinion was analyzed as distinct scenario discussing its strengths and weaknesses as unicriterion decision making, as well as altogether as multi-criteria decision making. The findings revealed the importance of involving all stakeholders in decision making process.

Investment in public projects is a complex business process that requires special attention, seriousness, and social responsibility, not only from direct public management, but also from wider social community. Selecting among variety of investment projects in a public administration portfolio can often be challenging because the projects are difficult to compare, and because the various interested parties view the projects in different ways. The complexity and multidisciplinarity of such problem suggest the need for multiple-criteria analysis and group decision making as well. To make prioritization of public investment projects, we design the model to evaluate and rank projects in local administration portfolio which is based on PROMETHEE methods. By conducting case study method data were obtained from the projects, thus resulting with criteria for further comparison. We simulated and validated this model using the portfolio of the Goranski sportski centar (GSC) for the Delnice city. Proposed model contributes to higher quality and more consistent prioritization of public investment projects, which is based on consensus of all stakeholders.

Problems related to the management of projects, specifically priority ranking problems, can be found in all stages of projects’ life cycles, mostly as the result of inadequate decision making. Such place where engineering students can be challenged both creatively and by knowledge in a complex project environment can be found in the graduate study programme under the course of Project Management at the Faculty of Civil Engineering in Rijeka. Priority ranking of student papers in faculty environment deals with complex decision making problems which is characterized by lots of participants, multidisciplinarity, huge quantities of information, different opinions as well as conflicting goals and criteria. In order to cope with such complexity and to help professors during evaluation process of student papers, the use of concept based on multi- criteria analysis for solving priority setting problem is proposed. The starting point of proposed concept is goal analysis and development of adequate criteria set. Evaluation of criteria importance is based on a set of experts’ opinions processed by AHP method, while all data processing is done by PROMETHEE multi- criteria methods. The main outcome of proposed concept is a rank list of student papers. Structuring such complex problems and considering multiple-criteria explicitly leads to more informed and better decisions, at the same time involving students in the process of setting up the concept making them active subjects nor end objects. Integration of multi-criteria analysis into evaluation process of student papers contributes to higher consistency in their priority ranking, and at the same time innovating curriculum of the course as it is introduced into education process of construction management.

The main goal of this paper was to compare the application of a budget and a PPP model in financing public standard structures in post- transition environment. The analysis was conducted on education and sports facilities by applying the multiple-case study. The research and analysis of numerous public construction projects which were carried out in transition and post-transition social circumstances has shown the occurrence of characteristic risks. The trend in the Republic of Croatia indicates an even more intensive interest of the state for financing the public facilities by using the private capital. The progress and condition prognosis of future PPP projects in post- transition economies points out a possible occurrence of several of previously recognized characteristic risks. Those are risks which, although allocated on the private partner, can have a negative effect on the public partner as well.

Due to everyday burst of technological developments and their application in the field of project management, there is a lasting need for improvement in student teaching and assessment processes. Such place where engineering students can be challenged both creatively and by knowledge in complex project environment can be found in the graduate study programme under the course of Project Management at the Faculty of Civil Engineering in Rijeka. As one of the course objectives is active work on actual project proposals, students are divided into supervised teams. Each team is responsible for the development of one project scenario for the Project Delta in the city of Rijeka, and is evaluated as the best project proposal among defined project teams and their proposals. Prioritization of project proposals deals with complex decision making. It is characterized by lots of participants, multidisciplinarity, huge quantities of information, limited budget, conflict goals, and criteria. In order to cope with such complexity and to help professors during decision making processes, this paper proposes the use of multi-criteria methods for solving priority setting problem. The starting point in this methodology is goal analysis and development of adequate criteria set. Evaluation of criteria importance is based on a set of experts’ opinions processed by AHP method, while all data processing is done by PROMETHEE multi-criteria methods. The end result is a priority list of student project proposals. By presented methodology specialized software is introduced into education process of construction management, thus innovating curriculum and assessment of the course.

Performance concept or approach in building is not new and can be traced back thousands of years. The concept is widely acclaimed and is applicable to both building procurement (design and construction) and to regulation (control), but has not been widely applied, especially in Croatia. In this approach the focus of all decisions is on the required performance-in- use, and on the evaluations and testing of building asset. The use of performance-based approach in the building industry allows more open competition, promotes transparent procurement, and supports cost- effective building. Particular application in building consists of translating human needs to user requirements, transforming them into technical performance requirements and quantitative criteria that do not dictate a prescribed solution, but rather compose a means for the investigation of various alternatives, and responding to these requirements during the various stages of conceptual, preliminary and detailed design to enable cost-effective construction of buildings that provide long- term satisfactory performance. Pluralism of private and public interests and goals in public management of urban areas is making decision making more complex. In such complex situation capital forms public interest, therefore in conditions of limited financial funds there is a need for partial interventions into public space. Defining, developing and implementing performance concept in construction management of education facilities will give the decision makers a right tool for making quality and consistent decisions which will be based on adequate data. Concept is based on multicriteria analysis taking into account various quantitative and qualitative building indicators. Current construction codes and standards determine minimal infrastructure, financial and human resource indicators for realization and development of education buildings. Disproportion that appears in construction practice directs to the need for establishing upper, maximum values indicators. Beside the quantitative indicators, it is necessary to define certain qualitative indicators (in term of various technical solutions, materials and other) that would lead to more rational solutions and improved management of government budget. This paper will provide a recent research and preliminary findings in development of performance concept in construction management of education facilities. Intention is to give a platform for decision makers in order to help them making fast, quality and appropriate decision upon value of each building element, and how will it reflect on total value of whole building.

Current construction codes and standards determine minimal infrastructure, financial and human resource indicators for realization and development of primary education. Disproportion that appears in construction practice directs to the need for establishing upper, maximum values indicators. The need for indicators is pointed out by the government of Republic of Croatia in its “General program for construction and reconstruction of public facilities according to public-private partnership” from 2012. The main goal of this paper is to present database of standards for construction, maintenance and utilization of educational system facilities in the Republic of Croatia. Beside the quantitative indicators, it is necessary to define certain qualitative indicators (in term of various technical solutions, materials and other) that would lead to more rational solutions and improved management of government budget. Database is organized in a table form, with technical, functional and quality indicators arranged in groups. Established database contributes to definition of the acceptable construction problem solutions for educational system facilities.

'Performance concept' u gradnji predstavlja pristup gradnji na temelju traženih zahtjeva koje izgrađeni objekt mora ispunjavati. Zahtjevi se mogu definirati pomoću različitih kriterija, od kojih jedan može biti vrijednost nekretnine. Definiranje, razvoj i implementacija pristupa gradnji u procjeni vrijednosti nekretnina mogla bi dati donositeljima odluka pravi alat za izradu kvalitetne i dosljedne odluke na temelju odgovarajućih podataka. Prema toj ideji stvoren je model za pristup gradnji na temelju traženih zahtjeva.

Svaki graditeljski projekt se može opisati kao nerutinski, neponovljivi i jedinstveni poduhvat koji ima zasebne vremenske, financijske i tehničke izvedbene ciljeve. Priprema koja prethodi realizaciji projekta mora se provesti temeljito i stručno jer će samo takav pristup omogućiti ostvarenje ciljeva projekta. U tome nam može pomoći integrirano programsko rješenje koje u značajnoj mjeri rješava pitanja organizacije, planiranja i kontrole izvedbe projekata. U radu je, za potrebe upravljanja projektima, dana usporedba dvaju najčešćih načina rada s računalom i računalnim softverima u hrvatskoj građevinskoj praksi. Prvi, konvencionalni način obuhvaća rad na računalu s osnovnim dijelovima MS Office paketa (MS Word i MS Excel) te MS Project-om, dok se u radu sa specijaliziranim softverima obuhvaća rad u integriranom programskom paketu. Rad u specijaliziranom softveru za upravljanje projektima, zbog integriranosti baza normativa rada, materijala i strojeva te kalkulacija jediničnih cijena, od pomoći je svim sudionicima građenja jer nudi bržu izradu ponuda, situacija, građevinskih knjiga, gantograma, histograma, S- krivulja i ostale dokumentacije neophodne za uspješno vođenje gradilišta kao i za upravljanje projektima. Navedene karakteristike omogućavaju izradu troškovno i vremenski učinkovitijeg plana organizacije građenja.