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Low flow of Kličevica watercourse
No full textU ovom radu obrađena je analiza malih voda vodostaja i protoka vodotoka Kličevice. Prikazani su minimalni vodostaji i protoci za svaki mjesec pojedinačno u periodu od 2010. do 2020. godine. Isto tako, korištenjem metode godišnjih ekstrema, prikazane su empirijske funkcije vjerojatnosti prema Čegodajevu. Kod metode pikova, osim proračuna empirijske funkcije raspodjele prema Čegodajevu, sadržana je i analiza određivanja visine praga te vrijednosti pikova za protoke i vodostaje. Vrijednost praga kod vodostaja i protoka usvojena je kao srednja vrijednost njihovih minimalnih mjesečnih iznosa. Osim toga definiran je prosječni period suše za vodotok Kličevicu te je provedena usporedba prosječne i vrlo sušne godine. Svi podatci korišteni za navedene analize preuzeti su s Državnog hidrometeorološkog zavoda. Svi proračuni i izrada dijagrama napravljena je uz pomoć programskog paketa Microsoft Excel
Physical properties of the soil in the walls of traditional eastern Croatia rammed earth houses
No full textIn eastern Croatia rammed earth houses were traditionally built in the past. The choice of suitable soil for building rammed earth houses depends on several soil properties. Moreover, since there are no standards or recommendations for construction of rammed earth houses in Croatia, the construction and renovation of such houses is almost non-existent nowadays. With the aim of forming detailed recommendations for eastern Croatia area in near future, soil samples were collected from existing houses to test the physical properties of the soil. Obtained results showed that Atterberg limits are within the limits of the recommended values and published results in the literature, while particle size distribution differs from most recommendations and published results
Editorial: Seismic resilience, vulnerability and energy efficiency in respect of climate change
No full textThe unfolding narrative of climate change is leaving indelible impacts worldwide, challenging the very fabric of urban infrastructure. As the environment undergoes swift and profound transformations—marked by soaring temperatures, recurrent flooding, and landslides—side by side with cataclysmic earthquakes, the vulnerabilities of our constructed landscapes emerge starkly. No longer can we remain mere spectators; the exigency now is to engage with solutions that encompass durability, sustainability, and resilience. In this backdrop, this Research Topic (RT) titled Seismic resilience, vulnerability and energy efficiency in respect of climate change centers on the vital intersection of seismic safety and energy efficiency. Traditionally viewed through distinct lenses, the zeitgeist now mandates a harmonized approach, embedding both these elements cohesively in architectural and structural strategies. The assemblage of contributions in this RT showcases a spectrum of critical reviews, insightful overviews, innovative methodologies, and empirical analyses, all charting a course through the intricate terrains of seismic resilience in a climate-altered world
Calibration of the Microsimulation Traffic Model Using Different Neural Network Applications
No full textThe efficacy of the application of traffic models depends on a successful process of model calibration. Microsimulation models have a significant number of input parameters that can be optimized in the calibration process. This paper presents the optimization of input parameters that are difficult to measure or unmeasurable in real traffic conditions and includes parameters of the driver’s behavior and parameters of Wiedemann’s psychophysical car-following model. Using neural networks, models were generated for predicting travel time and queue parameters and were used in the model calibration procedure. This paper presents the results of a comparison of five different applications of neural networks in calibrating the microsimulation model. The VISSIM microsimulation traffic model was selected for calibration and field measurements were carried out on two roundabouts in a local urban transport network. The applicability of neural networks in the process of calibrating the microsimulation models was confirmed by comparison of the modelled and measured data of traffic indicators in real traffic conditions. Methods of calibration were validated with two sets of new measured data at the same intersection where the calibration of the model was carried out. The third validation was made at the intersection in a different location. The selection of the optimal calibration methodology is based on the model accuracy between the simulated and measured data of traveling time, as well as queue parameters. The microsimulation model provides access to the raw data of observed traffic parameters for each vehicle in the simulation. The dataset of the calibrated model simulation results of all travel times of the selected traffic flow was compared with the dataset of the measured field data to determine whether the data are statistically significantly different or not
Seismic Performance Assessment of the 18th Century Jesuit College in Dubrovnik’s Old City
No full textThe seismic performance assessment of heritage architecture presents many challenges due to the restrictions set forth by the conservation principles to protect the associated social and cultural values. These buildings are typically characterized by unreinforced masonry walls connected to-gether by tie-rods, vaults, and wooden floors. The era of construction dates to the time when seismic design regulations were largely unknown, making the heritage structures potentially vul-nerable to earthquake damage. This study presents the seismic performance assessment of the Jes-uit College located in the southern part of the Old City of Dubrovnik. A series of field surveys were conducted to qualitatively examine the material composition and obtain geometrical details in part of the Croatian Science Foundation research project IP-2020-02- 3531 entitled “Seismic Risk Assessment of Cultural Heritage in Croatia - SeisRICHerCRO”. The structural response is thor-oughly investigated by means of a complex finite element model calibrated using the frequencies determined from ambient vibration measurements, and material characteristics obtained from the literature review of representative cultural heritage buildings. The seismic performance is evalu-ated using linear static and response spectrum analysis in accordance with Eurocode 8 guidelines for the demand seismic action level. The numerical analysis indicates several structural compo-nents in the building exhibiting high shear stress concentration and exceeding the elastic tensile limit under the demand ground acceleration level. The assessment further reveals substantial out-of- plane bending of vulnerable wall components (identified by local mode shapes) at low peak ground acceleration levels. The stress concentration in numerous structural components leads to the identification of vulnerable zones where retrofitting measures are essentially required
Pavement Structure Characteristics and Behaviour Analysis with Digital Image Correlation
No full textDigital image correlation (DIC) is a method of point displacement measurement by an optical system. If two cameras are used for capturing the same point displacement, threedimensional data are obtained using the 3D-DIC method. The areas of application of this method in pavement construction are diverse, but it is mainly used for displacement monitoring during standard tests of the failure of specimens due to load application. Furthermore, DIC technology was used only for testing particular material characteristics and assuming their influence on the overall pavement system. Within this research, DIC was applied in two areas: defining material mechanical characteristics and analyses of pavement structure behaviour under cyclic loading. The scope of this research was to gain more insights into DIC’s potential application within pavement behaviour analyses, specifically on cement-bound granular material (CBGM) characterisation. Results from this study confirm the suitability of 3D-DIC technology for pavement material characterisation. Furthermore, it is shown that certain trends of material behaviour defined on the simple material level of each independent pavement layer will significantly differ when it is placed in the system, and this kind of complex analysis is possible by using 3D- DIC technology
Modeling the Thermoelastic Bending of Ferric Oxide (Fe2O3) Nanoparticles-Enhanced RC Slabs
No full textNanoparticles, by virtue of their amorphous nature and high specific surface area, exhibit ideal pozzolanic activity which leads to the formation of additional C-S-H gel by reacting with calcium hydroxide, resulting in a denser matrix. The proportions of ferric oxide (Fe2O3), silicon dioxide (SiO2), and aluminum oxide (Al2O3) in the clay, which interact chemically with the calcium oxide (CaO) during the clinkering reactions, influence the final properties of the cement and, therefore, of the concrete. Through the phases of this article, a refined trigonometric shear deformation theory (RTSDT), taking into account transverse shear deformation effects, is presented for the thermoelastic bending analysis of concrete slabs reinforced with ferric oxide (Fe2O3) nanoparticles. Thermoelastic properties are generated using Eshelby’s model in order to determine the equivalent Young’s modulus and thermal expansion of the nano-reinforced concrete slab. For an extended use of this study, the concrete plate is subjected to various mechanical and thermal loads. The governing equations of equilibrium are obtained using the principle of virtual work and solved using Navier’s technique for simply supported plates. Numerical results are presented considering the effect of different variations such as volume percent of Fe2O3 nanoparticles, mechanical loads, thermal loads, and geometrical parameters on the thermoelastic bending of the plate. According to the results, the transverse displacement of concrete slabs subjected to mechanical loading and containing 30% nano-Fe2O3 was almost 45% lower than that of a slab without reinforcement, while the transverse displacement under thermal loadings increased by 10%
Drought Characterization in Croatia Using E-OBS Gridded Data
No full textDroughts are among the major natural hazards that are spreading to many parts of the world, with huge multi-dimensional impacts. An extensive analysis of drought phenomenon is presented for continental Croatia based on a meteorological E-OBS gridded dataset (0.25◦ × 0.25◦), within the period of 1950–2022. The drought events were characterized by the Standardized Precipitation Evapotranspiration Index (SPEI), applied to different time-scales (6 and 12 months), in order to describe the sub-annual and annual variability of drought. The spatio-temporal patterns of drought are obtained through principal component analysis (PCA) and K-means clustering (KMC) applied to the SPEI field. An areal drought evolution analysis and the changes in the frequency of occurrence of the periods under drought conditions were achieved using a kernel occurrence rate estimator (KORE). The modified Mann–Kendall (MMK) test, coupled with the Sen’s slope estimator test, are applied to the SPEI series in order to quantify the drought trends throughout the country. According to the history drought events and considering the different morpho-climatic characteristics of the study area, the results showed that Croatia could be divided into three different and spatially well-defined regions with specific temporal and spatial characteristics of droughts (central northern, eastern and southern regions). A manifest increase is shown in the percentage of area affected by drought, as well as in the yearly drought occurrences rates, in both central northern and eastern regions, and an evident decrease is shown in the southern region for both 6- and 12-month SPEI time-scales. In the observation of the drought’s temporal characteristics, it was found that downward trends expressing increasing drought severities were strongly significant in northern and eastern regions, while a few significant upward trends were seen in the southern region. From this study, it is possible to obtain a broader view of the historical behaviour of droughts in Croatia, with the results providing useful support for drought risk assessment and decision-making processes
Surface of pavement course made from recycled materials
No full textIndustrijalizacija i kontinuirani rast stanovništva uvelike su doprinijeli stvaranju raznih vrsta
otpada koji se najčešće nepravilno odlaže. Nepravilno odlaganje i gomilanje otpada ima negativne
učinke koji rezultiraju onečišćenjem okoliša. Štoviše, radi očuvanja okoliša ulažu se veliki napori
kako bi se osiguralo da se dio tog otpada reciklira i koristi ponovno u proizvodnji novih
alternativnih materijala. Ovaj rad opisuje različite reciklirane otpadne materijale koji se mogu
koristiti za izgradnju kolnika. Neki od opisanih recikliranih otpadnih materijala su guma, pepeo i
plastika. Ovi reciklirani materijali globalno su prihvaćeni zbog svojih karakterističnih svojstava
koja su ih učinila prikladnim u građevinskoj industriji. Ovaj rad također prikazuje neka ograničenja
i nedostatke koji se odnose na usvajanje ovih materijala kao alternativnih građevinskih materijala
za konstrukciju kolnika.Industrialization and continuous population growth have contributed to the creation of various
types of waste, which are usually improperly disposed. Improper disposal and accumulation of
waste has negative effects that result in environmental pollution. To preserve the environment,
great efforts are made to ensure that some of this waste is recycled and used again in the production
of new alternative materials. This paper describes various recycled waste materials that can be
used for pavement construction. Some of the recycled waste materials described are rubber, ash
and plastics. These recycled materials are globally accepted due to their distinctive properties that
have made them suitable in the construction industry. This paper also shows some limitations and
disadvantages related to the adoption of these materials as alternative materials for pavement
construction
Legislation in the field of building maintenance
No full textU ovom radu istražuje se zakonska regulativa u području održavanja građevina u Republici Hrvatskoj s naglaskom na zgrade javne namjene. Cilj rada je dati pregled relevantnih zakona, pravilnika, tehničkih propisa i standarda koji se odnose na održavanje javnih zgrada te izraditi plan i program održavanja zgrade za desetogodišnje razdoblje na primjeru zgrade Građevinskog i Arhitektonskog Fakulteta u Osijeku. U radu su detaljno objašnjeni temeljni koncepti održavanja definirani zakonom, obveze koje proizlaze iz zakona i važnost održavanja za očuvanje temeljnih zahtjeva za građevinu tijekom njezina trajanja. Prikazani su relevantni zakoni, pravilnici i tehnički propisi koji se moraju uzeti u obzir pri izradi plana i programa održavanja. Plan i program održavanja uključuje zakonom propisane aktivnosti održavanja kao i druge skupine aktivnosti koje su neophodne za osiguravanje funkcionalnosti, sigurnosti, dugoročnosti i estetike zgrade. Kao dio plana i programa održavanja izrađena je i financijska analiza svođenjem budućih troškova na sadašnju vrijednost metodom neto sadašnje vrijednosti te je izrađena i analiza osjetljivosti s obzirom na promjene diskontne stope. Na temelju plana i programa održavanja daju se preporuke za smanjenje troškova održavanja i za daljnja poboljšanja u području održavanja uključujući redovito praćenje stanja zgrada i ažuriranje planova održavanja radi osiguranja njihove dugoročne funkcionalnosti i očuvanja. Rad ističe važnost sustavnog planiranja i provođenja održavanja javnih zgrada.This paper investigates legislation in the field of building maintenance in the Republic of Croatia, with an emphasis on public buildings. The study aims to provide an overview of relevant laws, technical regulations, and standards pertaining to the maintenance of public buildings and to develop a plan for the maintenance of the building for ten years, using the example of the building of the Faculty of Civil Engineering and Architecture in Osijek. The paper explains in detail the basic maintenance concepts defined by the law, obligations arising from the law, and the importance of maintenance to preserve the basic requirements for the structure during its duration. Relevant laws and technical regulations that must be considered when drawing up the maintenance plan are presented. The maintenance plan and program shall include statutory maintenance activities and other groups of activities necessary to ensure the building's functionality, safety, longevity, and aesthetics. As part of the maintenance plan and program, a financial analysis was made by reducing future costs to present value using the net present value method, and a sensitivity analysis for changes in discount rates. The maintenance plan and program shall make recommendations for reducing maintenance costs and for further improvements in the field of maintenance, including regular monitoring of the condition of buildings and updating maintenance plans to ensure their long-term functionality and conservation. The paper emphasizes the importance of systematic planning and implementation to maintain public buildings