Repository of Faculty of Civil Engineering Osijek
Not a member yet
2575 research outputs found
Sort by
Stability problem - buckling
No full textU radu je analiziran problem stabilnosti osno opterećenih štapova pri djelovanju uzdužne tlačne sile. Rad se sastoji od teorijskog i praktičnog dijela. U teorijskom dijelu analiziran je problem stabilnosti štapova opterećenih uzdužnom tlačnom silom. Izvedeni su izrazi za izračun Eulerove kritične sile za osnovne slučajeve izvijanja. Praktični dio rada sastoji se od proračuna Eulerove kritične sile i vitkosti za jedanaest zadanih štapova različitog poprečnog presjeka. Kako bi dobiveni iznosi bili usporedivi zadani štapovi su iste duljine i površine poprečnog presjeka, ali različitog oblika. Svi štapovi promatrani u proračunu zglobno su pridržani na oba kraja. Usporedba dobivenih vrijednosti prikazana je na kraju praktičnog dijela u obliku tablice sa vidljivim rezultatima proračuna za svaki od jedanaest štapova zadanih poprečnih presjeka.The thesis analyzes the stability problem of axially loaded bars under the influence of longitudinal compressive force. It consists of a theoretical and a practical part. In the theoretical part, the stability problem of bars loaded with a longitudinal compressive force is analyzed. Expressions for calculating Euler's critical force for basic buckling cases are derived. The practical part of the paper consists of calculating Euler's critical force and slenderness for eleven given bars with different cross-sections. To make the obtained values comparable, the bars have the same length and cross-sectional area but different shapes. All bars considered in the calculations are pinned at both ends. A comparison of the obtained values is presented at the end of the practical part in the form of a table, showing the calculation results for each of the eleven bars with specified cross-sections
Analysis of the Impact of Agricultural Production Type and Traffic on Nitrogen Oxide Emissions
No full textThe protection of air from pollution is one of the basic principles of sustainable development, and this article analyzes the joint impact of various types of agricultural production and traffic on nitrogen oxide (NOx) emissions. The goal of this research is the development of a new methodology for assessing the combined impact of different types of agricultural production, traffic load, and traffic flow structure on the emission of nitrogen oxides. For the analysis of the joint impact of traffic and agricultural production, a new impact assessment methodology was developed, which is based on two selected impact prediction models. The following two models were used to predict the impact: the BioGrace model and the microsimulation model VISSIM. The developed methodology was applied to a case study in real field conditions. The results showed that the difference in the emission of NOx gases, depending on the type of agricultural production, indicates a reduction in NOx emissions in the walnut–winter-wheat system by 30%, compared to the production of winter wheat in an open field. The statistical analysis showed that there is no statistically significant difference between NOx emissions for different vehicle arrival scenarios for the same traffic load. The results of the joint impact show that the lowest NOx emission was found in walnut orchards and counted traffic. In this example, the difference between the one-hour emission load of three different agricultural types of production and traffic is not large; however, in the cumulative load, it can lead to significant differences. Emphasizing the importance of adopting new agricultural practices and the impact of traffic and the share of freight and heavy goods vehicles in agricultural production, we position them as a proactive and sustainable response to the critical ecological and agricultural challenges highlighted in European and Croatian policy
Visualization and analysis of seepage below the dam foundation
No full textThe analysis of water seepage below the model’s foundation of hydrotechnical object is conducted in the paper. A physical model of gravitational dam is made with the aim to visualize seepage through the ground below the dam. The model is made at the laboratory of the Faculty of Civil Engineering and Architecture in Osijek. The aim of the paper is to analyze the influence of the hydraulic gradient on seepage domain deformation, as well as to study the effect of different engineering measures on the decrease of hydraulic gradient. Four measurements were conducted which were mutually distinguished by the shape of the dam model, i.e. the foundation sheet. The first part of the paper is based on the assessment of measurement variants, i.e. engineering solutions used for the reduction of the seepage part of the buoyancy and seepage flow. The second part of the paper is dedicated to adoption of different models in the analysis of groundwater seepage below the object. Values related to seepage flow as well as buoyancy and pressure distribution below the foundation sheet were analyzed. Graphical, numerical, and approximate methods of analysis were used
Application of Artificial Intelligence Methods for Predicting the Compressive Strength of Green Concretes with Rice Husk Ash
No full textTo promote sustainable growth and minimize the greenhouse effect, rice husk fly ash can be used instead of a certain amount of cement. The research models the effects of using rice fly ash as a substitute for regular Portland cement on the compressive strength of concrete. In this study, different machine-learning techniques are investigated and a procedure to determine the optimal model is provided. A database of 909 analyzed samples forms the basis for creating forecast models. The derived models are assessed using the accuracy criteria RMSE, MAE, MAPE, and R. The research shows that artificial intelligence techniques can be used to model the compressive strength of concrete with acceptable accuracy. It is also possible to evaluate the importance of specific input variables and their influence on the strength of such concrete
Behaviour of cold-formed concrete-filled dual steel stiffened tubular short columns
No full textThis paper presents an experimental and numerical investigation into the behaviour of cold-formed concrete-filled dual steel-stiffened tubular (CFDSST) short columns under axial compressive load. This new composite column is fabricated from four cold-formed lipped angles to make the outer steel tube and a concentrically-placed steel tube located inside with concrete filled inside both the inner and outer tubes. The lips in the outer steel section behave as longitudinal stiffeners. To investigate the axial compression behaviour of these columns, fourteen CFDSSTs were designed and fabricated as well as two concrete-filled stiffened steel tubular (CFSST) columns and two concrete-filled double steel stiffened tubular (D-CFSST) columns for comparison. The columns failed due to local buckling of the outer steel tubes. The columns were modelled using finite element analysis and the accuracy and reliability of the numerical data was determined by comparing the numerical and experimental results. The validated model was employed to conduct a parametric analysis to investigate the behaviour of CFDSST columns with different variables and properties. The results show that the ultimate strength of CFDSST columns is most significantly influenced by the presence and strength of the sandwiched concrete between the two steel sections. The paper also presents an analysis of the accuracy and reliability of different international codified methods for predicting the load-carrying capacity of CFDSSTs
Primjena ekspertnih sustava u građevinarstvu
No full textEkspertni sustavi predstavljaju “IF-THEN” algoritme koji integriraju ljudsko ekspertno znanje radi rješavanja kompleksnih problema. Ovo područje istraživanja fokusira se na pronalaženje rješenja za izazovne situacije koje su često teško rješive klasičnim metodama. Ekspertni sustavi imaju veliku primjenu u građevinarstvu. U radu su prikazane neke od primjena: primjena kod održavanja građevina, inspekcije vodovodnih i kanalizacijskih sustava, primjena u geotehničkom inženjerstvu, održavanje prometnica te odabir odgovarajućih građevnih materijala. Umjetne neuronske mreže efikasne su kod optimizacije financijskog plana, procjene trajanja aktivnosti, procjene produktivnosti radne ekipe te izbora izvođača radova. Genetski algoritmi nalaze svoju primjenu u alokaciji resursa, odabiru optimalnih rješenja kod rasporeda zadataka i troškova projekata te održavanju građevina, dok fuzzy logika pomaže u analizi rizika, upravljanju projektima i procjeni troškova. Ekspertne metode mogu se integrirati u informacijske sustave kako bi pružile dosljedne informacije potrebne za učinkovito upravljanje građevinskim projektima. Pregled objavljenih radova o primjeni ekspertnih metoda u građevinarstvu pokazuje da su ove metode već značajno zastupljene u svim sektorima građevinarstva, ali također upućuje na to da postoje još velike mogućnosti za njihovu buduću primjenu
Simulation of the process of issuing the certificate of occupancy
No full textIn this paper, a discrete simulation model was developed for the certificate of occupancy (CO) for certain buildings issuance process in the Republic of Croatia. The model demonstrates the multistage nature of the process, with site inspections being the most time-consuming stage and a potential bottleneck. The model also shows that senior professional associates have the highest workloads. A what-if analysis was conducted to simulate the failure of the eDozvola system and to demonstrate the significant impact of such an interruption. A cost analysis of the CO issuance process demonstrated the potential for cost savings and efficiency gains through process optimization. Thus, simulation modelling can significantly improve the CO issuance process, resulting in cost savings, increased efficiency, greater stakeholder satisfaction, and better decision-making
Analysis of primary schools outdoor spaces in Osijek
No full textAnaliza vanjskih prostora osnovnih škola ima za cilj otkriti važnost vanjskih prostora za potrebe učenika. Analizom su uključeni razni segmenti vanjskih prostora kao što su pješački prilazni put, školski trg, kolni pristup, parkirališta, školski vrt, školsko dvorište te vježbalište. Svaki od ovih segmenata ima važan udio u cjelokupnoj analizi, a isto tako i u razvoju učenika. Sadržaj vanjskih prostora učenicima pruža mogućnost interakcije i zabave s vršnjacima, pospješuje njihov rast i razvoj, fizičku aktivnost te mentalno zdravlje. Oni pružaju pristup prirodi za svu djecu, a istovremeno zahtijevaju povremenu nadogradnju i uređivanje kako bi se zadovoljile nove školske potrebe. U radu su analizirani vanjski prostori osnovnih škola u Osijeku s posebnim naglaskom na školske vrtove, školska dvorišta, igrališta te vježbališta. Analizom je obuhvaćeno dvadeset osnovnih škola s podacima o njihovom nazivu, adresi, k.č. broju, površini čestice, površini zgrade,površini slobodnog dijela čestice i broju učenika.The analysis of the outdoor space of primary schools aims to reveal the importance of the outdoor space for the needs of students. The analysis included various segments of the outdoor space, such as the pedestrian approach road, school square, road access, parking lots, school garden, school yard and exercise field. Each of these segments has an important part in the overall analysis, as well as in the development of the student. The content of the outdoor space provides students with the opportunity to interact and have fun with their peers, promotes their growth and development, physics activity and mental health. They provide access to nature for all children, while requiring occasional upgrading and editing to meet new school needs. The paper analyzes the outdoor spaces of primary schools in Osijek with a special emphasis on school gardens, school yards, playgrounds and practise areas. The analysis includes twenty primary schools with dana of their name, adress, c.p. number, the area of the plot, the area of the building, the area of the free part of the plot and the number of students
The influence of segregation on the properties of lightweight concrete
No full textMnogobrojna istraživanja tijekom godina dovela su do toga da se laki beton koristi kao i obični beton. Laki beton u odnosu na obični beton ima manju gustoću, a samim time i manju čvrstoću. Rad obuhvaća utjecaj segregacije na svojstva lakog betona u svježem i očvrslom stanju te vrstu i količinu agregata na svojstva laganog betona.Many studies over the years have resulted in the use of light concrete as well as regular concrete. Light concrete has a lower density and thus a lower strength compared to regular concrete. The work covers the influence of segregation on the properties of light concrete in the fresh and hardened state, and the type and quantity of aggregate on the properties of light concrete
Architecture and urban design of Retfala south business zone
No full textZadatak završnog rada je idejno urbanističko i arhitektonski rješenje poslovne zone Retfala- jug. Urbanističko rješenje sastoji se od sedam poslovnih zgrada te jednog hotela. Sve su zgrade formirane kao hibridi lamele i tornja. Koncept rješenja poslovne zgrade proizlazi iz samog urbanističkog rješenja te iz njega izvlaći glavne odrednice kao što su zelenilo, središnji prostor za okupljanje, memorija mjesta. Priroda nagriza zgradu, oduzima joj površinu, a zgrada se pod utjecajem prirode izvija, savija te se stvara monumentalna konstrukcija te sam oblik zgrade. Prizemlje te prvi kat su polujavni i poluprivatni, dok je toranj od prvog kata naviše u potpunosti zaokupljen odjelima poslovne zgrade.The final project task is the urban and architectural solution for the Retfala- South business zone. The urban design consists of seven business buildings, and one that is hotel. All buildings are hybrids of lamella and the tower. The concept of business building design is closely connected to the thematic observation of the complex itself. It stems from the urban design itself and
extracts the main determinants from it, such as nature, central gathering space, place memory. Nature erodes the building, takes away its surface, and the building under the influence of nature warps,bends and creates a monumental structure. The ground floor and the first floor are semi- public and semi private, while the tower from the first floor upwards is completely occupied by the main departments of the building