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The textbook is primarily intended for students and as such fully covers the material from the Basics of Concrete Structures course at the Undergraduate University Study and from the Concrete Structures 1 and Concrete Structures 2 courses at the Undergraduate Professional Study of Civil Engineering FCEAG Split. It also partially refers to the material from the Concrete Structures 1 and Concrete Structures 2 courses at the Graduate University Study of Civil Engineering and the material from the Load-bearing Structures 1 course at the Undergraduate University Study of Architecture and Urbanism FCEAG Split. The author's intention is not to present the material in detail and widely, but to present the basics of calculation, dimensioning and design of reinforced concrete structures in a clear and concise manner. As it was created over a long period of time, the materials also followed the development of standards for the calculation of concrete structures, from PBAB, through the European preliminary standard, to the latest Eurocode for concrete: HRN EN 1992-1-1 :2013/A1:2015 (EC-2). The aforementioned standard, which is valid in the Republic of Croatia and according to which this edition of the textbook is aligned, today undoubtedly represents one of the most modern standards in the world for the calculation, dimensioning and design of reinforced concrete structures.

The results of the shake‐table study on the effect of longitudinal reinforcement ratio on the behavior of concrete columns are shown. The small‐scale (1 : 3) model of cantilever columns with mass at their top was exposed to horizontal acceleration of an artificial accelerogram. Acceleration amplitudes were successively increased until the collapse of the columns. Characteristic displacements and accelerations, as well as strains in the concrete and reinforcement were measured during the shake‐ table tests. It was concluded that the ultimate bearing capacity and deformability of a column significantly depend on the amount of its longitudinal reinforcement. By increasing the amount of longitudinal reinforcement, ultimate bearing capacity of the column is also increased, but not proportionally. The reason is greater stiffness of the column with higher amount of longitudinal reinforcement than of the column with low amount of longitudinal reinforcement, which generates greater seismic forces in it for the same excitation.

The basic characteristics of the three historic stone arch bridges over the Cetina River in Croatia are presented firstly. The bridges are under protection of the Ministry of Culture of the Republic of Croatia as valuable architectural heritage. The current state of the bridges is then presented ; and the main solution of the renovation and strengthening of the bridges is briefly explained. A conclusion is reached that the renovation of the bridges was performed successfully, with excellent cooperation between the engineers and the conservators.

Firstly, a finite element numerical model for nonlinear dynamic analysis of masonry walls is briefly presented. The model can simulate the main nonlinear effects of masonry and reinforced concrete. It is simple and intended to the engineering application. A macro model of masonry is adopted for simulation its behaviour in compression and for cracks modelling in tension. Two constitutive models are implemented to describe the shear resistance of the masonry wall: one that does not take the effect of the shear failure of masonry (Model 1), and second which takes into account shear failure of masonry (Model 2). By using the numerical model, the shear effect of masonry on the behaviour of two-storey unreinforced and confined masonry walls exposed to harmonic base acceleration was investigated. The height to length ratio of the walls and the quality of masonry are varied. Analysis results for Model 1 and Model 2 are significantly different. Model 1 gives a significantly higher load bearing capacities of masonry. It was concluded that the shear effect of masonry significantly depends on the type of the masonry walls (unreinforced, confined), the quality of the masonry and height to length ratio of masonry walls.

This paper firstly briefly describes developed numerical model for both static and dynamic analysis of planar structures made of concrete, steel and masonry. The model can simulate the main nonlinearity of such individual and composite structures. The model is quite simple and based on a small number of material parameters. After that, three real composite concrete-steel-masonry bridges were analyzed using the presented numerical model. It was concluded that the model can be useful in practical analysis of composite bridges. However, future verifications of the presented numerical model are desirable.

The effect of the height-to-length ratio of unreinforced and confined masonry walls under horizontal static and seismic loads was numerically investigated by using a previously developed numerical model of the authors for nonlinear static and dynamic analysis of masonry structures. The model can simulate the main nonlinear effects of construction materials and large displacements of structures. Masonry walls without openings were analysed, with variants of rigid and soft masonry. It was assumed that wall foundation uplifting is possible, without its slipping beyond subsoil. Masonry walls with equal height and different length, and masonry walls with equal length and different height were analysed. It was concluded that the height-to-length ratio of masonry walls has a significant influence on their ultimate bearing capacity under static and seismic loads. Der Effekt des Hohen-Langen-Verhaltnis von unverstarktem und verstarktem Mauerwerk unter horizontal statischen und seismischen Lasten wurde numerisch mit Hilfe eines zuvor entwickelten Modells der Autoren fur die nichtlineare statische und dynamische Analyse von Mauerwerk untersucht. Das Modell kann die wichtigsten nichtlinearen Effekte bei Baustoffen und grose Verschiebungen von Strukturen simulieren. Mauerwerk ohne Offnungen wurde analysiert, wobei die Varianten von hartem und weichem Mauerwerk berucksichtigt wurden. Es wurde dabei angenommen, dass das Wandfundament – ohne Rutschen uber den Untergrund – abheben kann. Mauerwerk mit gleicher Hohe und unterschiedlicher Lange und Mauerwerk mit gleicher Lange und unterschiedlicher Hohe wurde untersucht. Es wurde gefolgert, dass das Hohe-zu-Lange-Verhaltnis von Mauerwerk einen signifikanten Einfluss auf die Bruchtragfahigkeit unter statischen und seismischen Belastungen hat.

The paper presents the results of experimental tests with a numerical comparison of some typical composite element systems. Two different kinds of elements were tested: composite steel-concrete and composite wood- concrete elements. Deflections at midspan under monotonously increasing static load on simply supported beams were measured. The affects of different types of composite connections on the results were researched. In numerical tests the structure was modeled with two-dimensional plane elements. The composite surface was modeled with two-dimensional contact (interface) elements for the continuous connection simulation and modified beam elements for the discrete connection simulation. The applied material models include the most important nonlinear effects of concrete, steel and wood behavior, as well as the nonlinear behavior of the composite surface at the connection. The achieved results of the developed numerical model were compared with the results obtained through the experimental test.

A numerical model is presented for both static and dynamic analysis of planar masonry-infilled steel frames, which are loaded only in their plane. The model can simulate all main nonlinear effects of the frame-infill-foundation-soil system. With this model, bare steel and concrete frame structures, masonry structures, as well as masonry-infilled steel and concrete frame structures can be analysed. Verification of this model was performed on two experimental tests. In example 1 a masonry-infilled steel frame under static cyclic load and in example 2 a masonry-infilled steel frame under dynamic load were analysed. The obtained numerical results agree well with experimental results. Ein numerisches Modell zur statischen und dynamischen Analyse von ebenen mit Mauerwerk verstarkten Stahlrahmen, die nur in ihrer Ebene belastet werden, wird vorgestellt. Das Modell kann alle gangigen Nichtlinearitaten des Rahmen-Ausfachung-Fundament-Boden Systems simulieren. Mit diesem Modell konnen Stahl- und Betonrahmenstrukturen, Mauerwerksstrukturen, aber auch mit Mauerwerk verstarkte Stahl- und Betonrahmenstrukturen analysiert werden. Die Verrifizierung des Modells erfolgte mittels zweier Experimente. In Beispiel 1 wurde ein Mauerwerk verstarkter Stahlrahmen unter statischer Last und in Beispiel 2 ein Mauerwerk verstarkter Stahlrahmen unter dynamischer Last untersucht. Die numerischen Ergebnisse stimmen gut mit den experimentellen Werten uberein.

This paper presents the numerical test results that consider the effect of anisotropy on the behaviour of unreinforced and confined masonry walls under horizontal harmonic ground acceleration. Two-storey masonry walls with different lengths (3m, 6m, 12m) are analysed. The wall foundations are supported on a rigid base, with possibility of lifting. A non-linear macro model of masonry is used. Cases of strong masonry (high strength and stiffness) and weak masonry (low strength and stiffness) are analysed. Different coefficients of anisotropy of masonry ca (0.2, 0.4, 0.6, 1.0) are considered. It is adopted that excitation period corresponds to the fundamental period of individual elastic wall. Horizontal displacement at the top of the walls, vertical stresses in masonry and concrete at the bottom of the walls and stresses in the longitudinal bars at the bottom of the vertical ring beams are shown for each analysed case. It is concluded that the ultimate bearing capacity and deformability of walls, as well as stresses in masonry, concrete and reinforcement under dynamic excitation significantly depend on the anisotropy of masonry. It is also concluded that, with the same coefficient of anisotropy, the behaviour of masonry walls depends on its type (unreinforced, confined), height to length ratio (0.5, 1.0, 2.0), and the quality of masonry (strong, weak).

This paper describes, in detail with the aid of pictures and annotated drawings, the solution for the pedestrian wooden bridge in the old town centre of Trogir in Croatia. The bridge made completely of natural solid oak wood consists of two-hinged arches of 25m span and all the bridge elements are made of the same wood connected by traditional carpentry joints. Design and calculations are in accordance with the appropriate Euro codes (1-4) and details of the woods preparation and preservation are given along with the techniques employed. Details of the foundations under the arch footing are given and the treatment of the soil under the reinforced concrete blocks is explained.

The previously developed numerical model of the authors for the analysis of conventional reinforced and prestressed concrete shells under short-term and long-term loading was improved by including the effects of transverse shear stresses on the shell failure. The 9-node degenerated shell element with the layered material model through the thickness of the shell was used. The reinforcement was modelled as a separate layer. To include the effect of transverse shear stresses on the shell failure, the failure criterion for concrete and longitudinal reinforcement was defined by a relation of transverse shear stresses and normal stresses in two mutually perpendicular vertical planes. The total transverse shear bearing capacity of the shell cross-section is obtained by summing up the concrete and reinforcement contributions. The developed numerical model and appropriate software were verified based on experimental tests.

Firstly, the main problems of numerical analysis of masonry structures are briefly discussed. After that, a numerical model for static and dynamic analyses of different types of masonry structures (unreinforced, reinforced and confined) is described. The main nonlinear effects of their behaviour are modelled, including various aspects of material nonlinearity, the problems of contact and geometric nonlinearity. It is possible to simulate the soil-structure interaction in a dynamic analysis. The macro and micro models of masonry are considered. The equilibrium equation, discretizations, material models and solution algorithm are presented. Three solved examples illustrate some possibilities of the presented model and the developed software for static and dynamic analyses of different types of masonry structures.

A numerical model for numerical analysis of reinforced and prestressed concrete plates and shells including creep and shrinkage of concrete, already developed by the authors, has been updated with presented nonlinear creep model for concrete. The model can be applied for all levels of concrete stresses, while its use for ultimate stress levels is still not fully tested. Presented nonlinear creep model is simple, based on the well known linear model of concrete creep, and intended for simulation of practical concrete structures. For the verification of the presented model, experimentally tested square concrete plate and cylindrical concrete shell were analysed numerically. The results of experimental tests at high stress levels and numerical results are similar. Some additional experimental tests for testing of the presented nonlinear creep model in practice and its eventual updating are planned.

Prikazano je rješenje pješačkog drvenog mosta preko kanala Foša u Trogiru kojim ga se nastojalo uklopiti u ambijent grada. Montažno-demontažnu rasponsku konstrukciju mosta tvore dva dvozglobna drvena luka raspona 25 m. Lukovi su povezani poprečnim gredama, iznad kojih je izvedena dvoslojna križna daščana podloga. Svi su dijelovi rasponskog sklopa izvedeni iz masivne hrastovine. Spojna sredstva su vijci i moždanici. Ispod mosta moguć je prolaz plovila visine do 4,5 m., The solution used for the wooden footbridge across the Foša Canal in Trogir, specifically aimed at blending this structure with its urban surroundings, is presented. The mountable-dismountable superstructure of this bridge is formed of two double-hinged wooden arches, 25 m in span. The arches are linked with cross beams, above which a two layered cross-boarded surface was realized. All superstructure segments are made of massive oak-wood. Bolts and stud connectors were used as connecting elements. Vessels up to 4.5 m in height can pass under the bridge.

U radu su prikazani rezultati statičke i dinamičke analize lučnog kamenog mosta u Mostaru koristeći prethodno razvijeni numerički model autora za statičku i dinamičku analizu različitih tipova zidanih konstrukcija. Razmatrana su dva modela geometrije mosta, s mikro i makro modelom ziđa. Analiziran je utjecaj vertikalnih opterećenja, temperaturnih promjena i djelovanje realnog potresa. Proračunski progibi i zone pukotina u luku dobro se slažu sa stvarnim stanjem, što potvrđuje pouzdanost korištenog numeričkog modela. U radu se ukazuje na potrebu hitne sanacije oštećenja obnovljenog kamenog luka., The static and dynamic analysis results for the arch stone bridge in Mostar are presented. The analysis is based on the numerical model previously developed by the author for static and dynamic analysis of various types of masonry structures. Two bridge geometry models, with micro and macro modelling of masonry, are considered. The influence of vertical load, temperature change, and real earthquake action, is analyzed. The design deflections and crack zones in arch correspond well to the real life situation, which confirms reliability of the numerical model used. It is emphasized in the paper that the damage to the renovated stone arch should be remedied as soon as practicable.

U radu su prikazani rezultati numeričkih testova utjecaja vertikalnih serklaža na ponašanje zidanih zidova pod statičkim i dinamičkim opterećenjem. Analizirani su dvoetažni zidovi bez otvora i s otvorima, s dobrim i lošim ziđem, s različitim rubnim uvjetima na spoju temelja zida i podloge. Istražen je utjecaj profila uzdužnih šipki vertikalnih serklaža na ponašanje zidova za horizontalna statička opterećenja te za harmonijska i potresna ubrzanja podloge. U analizi je primijenjen prethodno razvijen numerički model autora za statički i dinamički proračun ravninskih zidanih konstrukcija., Numerical test results, defining influence of vertical tie columns on the performance of masonry walls subjected to static and dynamic load, are presented in the paper. The analysis focuses on two-storey walls without openings and with openings, with good and poor quality masonry, and with different boundary conditions at the contact between wall foundations and the subsoil. The influence of the profile of longitudinal bars of vertical tie beams on the performance of walls under horizontal static load, and harmonic and seismic acceleration of subsoil, is studied. The numerical model for static and dynamic analysis of in-plane masonry structures, previously developed by the authors, is used in the analysis.