Bankama kao financijskim institucijama je jedna od glavnih aktivnosti primanje depozita i posuđivanje novca. Banke imaju znacajnu ulogu u održavanj

The paper deals with accurate determination of the relationship between bending moment and curvature of hollow rectangular bridge columns. With the calculation procedure to determine accurate curve of relationship, the method of determining the idealized diagram typically used in practice is also shown. The aim of this work is to point to a reserve in load capacity of an element when comparing the results of an accurate curve and the idealized diagram, and to analyse the impact of various calculation situations on the curve shape. The conclusion is that for practical use it is sufficient to use the idealized diagram, but for detailed scientific analysis the exact relationship between bending moment and curvature must be determined.

The paper provides a review of durability issues of the Adriatic large concrete arch bridges built in two periods: in the 1960’s and 1970’s and at the last turn of the century. Inadequate attention to durability issues in combination with very aggressive maritime environment has led to rapid deterioration of the structures caused by corrosion of reinforcement steel in concrete. In order to develop consistent maintenance policy that would provide efficient and effective management of bridges in maritime environment, it is necessary to determine remaining service life of the structures. In this purpose the coupled 3D chemo- hygro-thermo mechanical model is developed and implemented into FE code. The applications of the model are illustrated on three numerical examples. The numerical results are in good agreement with the available experimental data leading to the conclusion that the model is able to realistically predict service life of reinforced concrete structures exposed to chlorides and mechanical damage results. In service performance of the Adriatic large concrete arch bridges shown and numerical analysis confirmed the following: (i) cracks in concrete cover, which are the consequences of mistakes in conceptual design as well as errors and negligence on site, significantly reduces depassivation time of reinforcement bar ; (ii) corrosion rate is much higher in poor than in good quality concrete ; (iii) the maximal numerical results of corrosion rate, achieved at critical water saturation, are within the limits for concrete in splash zone, as one of the most critical environment for corrosion of steel in concrete, (iv) corrosion induced cracks significantly reduce pull-out capacity of reinforcement.

New Zagreb airport terminal is currently being built following the winning design from an international competition called upon by Zagreb City in 2008. After some pause, the project was rebooted in 2012, when Croatian government signed a concessionary agreement with French company Bouygues for the erection of the terminal according to the winning design, granted some minor changes. The awarded design by two architects Branko Kincl and Velimir Neidhardt, and one structural civil engineer Jure Radic, comprises an integral multidimensional approach between the structure, form, urbanism, ecology, functionality and aesthetics. The identity of the building is achieved with an elegant double curvature fluid form of its roof structure which comprises a steel space truss with spans of 43 m. The inner structure of the terminal is all concrete and monolithic, comprising mainly prestressed floor slabs (spanning 7.2 m and 14.4 m) and shear walls.

The necessity of joining structural and architectural approaches to reach human-oriented structures and develop contemporary urban environment is presented through several examples. Projects of an airport, a stadium and few bridges as outcomes of collaboration between structural engineers and architects will be overviewed.

The project of new Zagreb Airport Terminal is currently the largest civil engineering undertaking in Croatia. Almost 66.000 m2 of the Terminal will accommodate 5 million passengers per year, 3 times more than the current Terminal. The project started in 2008 when a competition was called upon by Zagreb City. In an international competition the winning design was chosen from a group of authors comprising two architects – Branko Kincl, Velimir Neidhardt, and one civil engineer – Jure Radic. This terminal design distinguished itself among competition in its integral multidimensional approach between the construction, form, urbanism, ecology and functionality. After some pause due to financial shortcomings, the project was again rebooted in 2012, when Croatian government signed a concessionary agreement with French company Bouygues and its local partners. Concessioner agreed to finance the whole project, including design, erection and service, in exchange for 30 years exploitation privileges. The main design started in 2012 according to the winning design with some compromises made in order to further optimize cost. The main identity of the building, its architectural and landmark trademark which is achieved with an elegant double curvature fluid form of its roof structure, was not to be changed. The inner concrete structure was optimized to allow for larger spans accommodating to more flexible airport needs, and ultimately a more durable construction. The erection of the Terminal started in late 2013. Until now all concrete structure has been finished, and roof steel truss is being assembled. The opening is scheduled for late 2016.

A fixed link between all parts of Croatian territory will be established after completion of the Mainland–Pelješac Peninsula Bridge over a navigable sea strait, with minimum required navigation clearance of 200x55m. The bridge is located in the high-activity seismic zone with design ground accelerationag=0,41g, strong winds and extremely adverse foundation soil conditions. The original main design of the bridge was completed and building permit was obtained. The construction of the bridge began in 2007, but it was slowed down and finally stopped in 2012 due to financial problems. Two alternative bridge solutions were proposed in the new preliminary design, a continuous steel beam bridge and a multi-span extradosed semi-integral bridge with hybrid deck. After a short account of the original bridge design, both preliminary designs are described in the paper. The multi-span extradosed semi-integral bridge with hybrid deck was chosen for further design.

The bridge management system used on the national road network of the Republic of Croatia does not contain the deterioration forecasting model that could be used for planning future remedial activities. A database on the condition of bridge elements has nevertheless been compiled, containing numerical values of the degree of deterioration. Results obtained by analysing usability of three deterioration models are presented in the paper in order to estimate which one would be the most favourable for Croatian conditions. The model based on the Markov process was found to be the most appropriate.

Research on development of seismic assessment procedure for existing bridges will be presented in this paper. Both the linear response spectrum analysis and the nonlinear static pushover method are used and results were evaluated following the demands defined by current European seismic design codes. At first, this procedure is validated by its application to major Adriatic arch bridges with spans ranging from 200 m to almost 400 m as a part of an extensive project to develop their appropriate maintenance strategy. Seismic assessment is further developed and their suitability is proved at different bridge types.

Main challenge during design of an attractive bridge is that its structure usually needs to appeal to three types of viewer – engineers, architects and the general public. Each of these groups has a different understanding of structures. However, there are numerous examples of fine bridge engineering at which all three groups can agree about functionality and beauty of structure and, many of them are arch bridges. According to the lists of the most popular bridges, created by general public ; the historic bridges inscribed on the UNESCO World Heritage List and the structures admired by engineers, it can be concluded that arch bridges are considered as the most attractive bridge type from ancient aqueducts to the contemporary structures. Arch bridges in Croatia, shortly presented in the paper, are according to their structural, aesthetic or functional characteristics among the World top achievements of their time.

Zagreb, Croatian capital, is situated on both Sava river banks. However, currently there are only seven bridges across the river in the inner city limits. To solve the problem of the inadequate capacity of the Sava River crossing in Zagreb, two new bridges are planned in the near future as part of the solution for sustainable development of the Sava River banks area in Zagreb. Differences in planning and design of bridges in 20th and 21st century will be analyzed highlighting new applied, holistic approach to design Jarun and Bundek Bridge.

Properly designed reinforced concrete structures can be very durable in most environments. However, in some cases, surface protection of concrete must be executed to achieve the required service life of a new structure (preventive measure), or to extend the service life of a repaired concrete structure. Surface protections are products and systems that contribute to the durability of concrete and reinforced concrete structures. Rapid degradation and reduction of service life generally occurs on reinforced concrete structures in a maritime environment, although they are designed according to the regulations in force at present and to the European standards 206-1 and 1992-1-1.The most common cause of degradation of reinforced concrete structures is corrosion of the reinforcement. In maritime environments chlorides are always a relevant environmental action. Durability of reinforced concrete structures is therefore determined by the ability of aggressive agents from the surrounding environment to penetrate into the elements. Since all agents, as well as climate and environment, have an impact on the external side of concrete, surface protection of concrete is an important factor for durability of a structure because it extends the initiation period of reinforcement corrosion by restraining penetration of water, chlorides, sulphates, acids and other aggressive agents. The aim of this research was to determine the influence of surface protection on the extension of durability of reinforced concrete structures in the maritime environment. Based on field and laboratory testing, testing methods for essential properties for surface protection systems in the maritime environment are proposed. Furthermore, assessment criteria for essential properties for surface protection systems in the maritime environment are given, and the correlation between the surface protection system and essential properties is determined. Keywords: bridgesdurabilitymaritime environmentsurface protection

Research on development of assessment procedures for existing bridges exposed to wind load will be presented in this paper. Both linear and the nonlinear methods are used and a probabilistic model of wind load is developed. The results were evaluated following the demands defined by current European design codes and specific location conditions. This procedure is validated by its application to major Adriatic arch bridges with spans ranging from 200 m to almost 400 m as a part of an extensive project to develop their appropriate maintenance strategy.

Given that visual inspection is vital when evaluating the condition of bridges, it plays a crucial role in planning the special maintenance works. At the beginning of 2012,a research was conducted in HAC (Croatian Highways) aiming to standardize evaluation of bridges. The bridge engineers had assessed a certain group of buildings, and their results were afterwards analysed using the mathematical statistics methods. The obtained results showed weaknesses in the existing evaluation system, and the conducted research created a base for improving aides for management, handbooks and procedures for bridge inspection.

The design solution presented by authors from the Faculty of Architecture and Faculty of Civil Engineering won the first prize award at the international competition organized by the Zagreb Airport. The structure and form of this solution are integrated through multidimensional approach in which individual factors - town planning, environmental aspects, architecture, structure, functionality, and traffic - are not given precedence one over another, but are rather evaluated as a whole made of equal parts. The principal airport building is covered with a fluid steel truss structure, which continuously expands into linear, tubular passenger piers on each side. The terminal building constitutes, together with proper regulation and development of surrounding space, a new dimension of development of the city of Zagreb, and its merger with Velika Gorica.

Components of concrete structures maintenance that represent major challanges to engineers are discussed and referred to the examples from practice. Repair and reconstruction works on reinforced concrete structures are not only expensive, but technically demanding tasks and very difficult to perform. Therefore, the decision to repair or replace a structure should be taken only after extensive investigation works and structural analysis. To ensure efficient structure management it is necessary to predict service life of new or already damaged structures utilizing a numerical model able to realistically simulate deterioration processes and its effects on safety of a structure. Activities on management system of the seven large reinforced concrete arches on the Croatian coast are briefly described highlighting importance of consistent maintenance policy.