Repository of Faculty of Civil Engineering Osijek
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Architectural - urban design of Retfala south business zone
No full textProjektirana poslovna zgrada smještena je na periferiji grada Osijeka, unutar poslovne zone Retfala Jug. Urbanističkim planom određena je lokacija poslovnih zgrada i jednog nebodera, uz osigurane pješačke i kolne komunikacije unutar cijelog urbanističkog obuhvata. Arhitektonsko rješenje posvećeno je poslovnoj zgradi koja se nalazi na jugoistočnom dijelu obuhvata. Koncept zgrade inspiriran je željom za stvaranjem stimulativnog radnog okruženja za korisnike. Primarna misao vodilja bila je oblikovanje prostora koji potiče neformalne susrete i interakcije, čime se tradicionalno radno okruženje transformira u dinamičniji i opušteniji ambijent. Arhitektonsko rješenje zgrade počiva na upotrebi organskih formi koje se protežu kroz cijeli volumen zgrade. Uklanjanjem dijelova volumena stvorene su dvoetažne terase koje zaposlenicima omogućuju pristup otvorenom prostoru, gdje mogu raditi ili se
opuštati na svježem zraku. Prizemlje zgrade ima javnu funkciju, s prostorima poput izložbenog prostora, kafića i savjetovališta za građane. Na višim etažama nalaze se uredski prostori i prateći sadržaji za korisnike zgrade. Temeljni oblikovni element zgrade predstavljaju dvoetažne organske terase koje dominiraju pročeljima. Fasadu dodatno oblikuje konstruktivni sustav, vidljiv izvana, te metalna mreža koja obavija zgradu i služi kao zaštita od sunca.The planned office building is located on the outskirts of Osijek, within the Retfala Jug business zone. The urban plan designates the location for office buildings and a skyscraper, with pedestrian and vehicular connections integrated throughout the urban area. The architectural solution focuses on the office building situated in the southeastern part of
the zone. The concept of the building stems from the desire to create a stimulating work environment for its users. The primary guiding idea was to design a space that encourages informal encounters and interactions, thereby transforming the traditional workplace into a more dynamic and relaxed environment. The architectural solution of the building is based on
the use of organic forms that extend throughout the entire volume of the building. By subtracting parts of this volume, two-story terraces were created, allowing employees access to open spaces where they can work or relax in the fresh air. The ground floor has a public character, featuring spaces such as an exhibition area, a café, and a counseling center for citizens.
The upper floors are designed with office spaces and accompanying facilities for the building's users. The fundamental design element of the building is represented by the two-story organic terraces that dominate the facades. The facade is further shaped by the visible structural system and a metal mesh that envelops the building, also serving as sun protection
Activation of immovable cultural heritage in tourism - case study of the city of Virovitica
No full textRad se bavi aktiviranjem nepokretne kulturne baštine u turizmu na primjeru grada Virovitice. U prvom dijelu rada dan je pregled definicija koje su vezane uz pojam kulturne baštine i koji se koriste u radu. U središnjem dijelu fokus je stavljen na povijesni razvoj grada Virovitice, turizam i kulturu kakvu danas poznajemo na tom području. Rad se dotiče glavnih kulturnih obilježja grada ali i turističkih ponuda koje se nude posjetiteljima. U završnom dijelu prikazan je intervju proveden s interesnim dionicima iz kulture i turizma u kojem ukazuju na sve pozitivne strane virovitičkog turizma ali i njegove propuste pa stoga predlažu određene ideje kao potencijalna rješenja tog problema. Na kraju se sažimaju ishodi istraživanja i iznosi se kritičko mišljenje koje se temelji na prikupljenim podacima
Prediction of reinforced concrete walls shear strength based on soft computing-based techniques
No full textThe precise estimation of the shear strength of reinforced concrete walls is critical for structural engineers. This projection, nevertheless, is exceedingly complicated because of the varied structural geometries, plethora of load cases, and highly nonlinear relationships between the design requirements and the shear strength. Recent related design code regulations mostly depend on experimental formulations, which have a variety of constraints and establish low prediction accuracy. Hence, different soft computing techniques are used in this study to evaluate the shear capacity of reinforced concrete walls. In particular, developed models for estimating the shear capacity of concrete walls have been investigated, based on experimental test data accessible in the relevant literature. The adaptive neuro-fuzzy inference system, the integrated genetic algorithms, and the integrated particle swarm optimization methods were used to optimize the fuzzy model’s membership function range and the results were compared to the outcomes of the random forests (RF) model. To determine the accuracy of the models, the results were assessed using several indices. Outliers in the anticipated data were identified and replaced with appropriate values to ensure prediction accuracy. The comparison of the resulting findings with the relevant experimental data demonstrates the potential of hybrid models to determine the shear capacity of reinforced concrete walls reliably and effectively. The findings revealed that the RF model with RMSE = 151.89, MAE = 111.52, and R2 = 0.9351 has the best prediction accuracy. Integrated GAFIS and PSOFIS performed virtually identically and had fewer errors than ANFIS. The sensitivity analysis shows that the thickness of the wall (bw) and concrete compressive strength ( fc) have the most and the least effects on shear strength, respectively
Ensemble learning based compressive strength prediction of concrete structures through real‑time non‑destructive testing
No full textThis study conducts an extensive comparative analysis of computational intelligence approaches aimed at predicting the compressive strength (CS) of concrete, utilizing two non-destructive testing (NDT) methods: the rebound hammer (RH) and the ultrasonic pulse velocity (UPV) test. In the ensemble learning approach, the six most popular algorithms (Adaboost, CatBoost, gradient boosting tree (GBT), random forest (RF), stacking, and extreme gradient boosting (XGB)) have been used to develop the prediction models of CS of concrete based on NDT. The ML models have been developed using a total of 721 samples, of which 111 were cast in the laboratory, 134 were obtained from in-situ testing, and the other samples were gathered from the literature. Among the three categories of analytical models—RH models, UPV models, and combined RH and UPV models; seven, ten, and thirteen models have been used respectively. AdaBoost, CatBoost, GBT, RF, Stacking, and XGB models have been used to improve the accuracy and dependability of the analytical models. The RH-M5, UPV-M6, and C-M6 (combined UPV and RH model) models were found with highest performance level amongst all the analytical models. The MAPE value of XGB was observed to be 84.37%, 83.24%, 77.33%, 59.46%, and 81.08% lower than AdaBoost, CatBoost, GBT, RF, and stacking, respectively. The performance of XGB model has been found best than other soft computing techniques and existing traditional predictive models
The Source of K Fertilizer for Industrial Hemp (Cannabis sativa L.): Mechanical and Chemical Properties of Stem for Rammed Earth Walls
No full textIndustrial hemp, as a natural plant fiber, has received increased research attention recently. Potassium fertilization is one of the most important fertilizers for plant stem thickness, but how the formulation of K fertilizer influences stem morphology and stem tensile strength remains unclear. This study aims to examine the influence of K fertilizer sources on industrial hemp stem properties, with a specific focus on the fibers, to evaluate their potential applications as reinforcement material for stabilizing rammed earth in sustainable construction. A field experiment was set up with different K fertilizer types applied as pre-sowing fertilizer in the following doses: K0—control, K1—100 kg ha−1 KCl, and K2—100 kg ha−1 K2SO4. Different K fertilizations did not have significant influence on stem height, which was on average 71.2 cm, nor on stem diameter, which was on average 3.4 mm. Regarding the macronutrient content of the industrial hemp stem (N, P, and K), K fertilization treatment significantly influenced (p < 0.05) their accumulation. The N, P, and K content in the stem within fertilization treatment averaged 0.78, 0.72, and 1.26%, respectively. The average content of cellulose, hemicellulose, and lignin was not significantly different in relation to K fertilization treatments. In the stem, dry weight cellulose content varied from 57.8% (K0) to 59.0% (K1), hemicellulose from 11.0% (K2) to 11.6% (K0 and K1), and lignin from 10.2% (K2) to 10.5% (K0). The tensile strength and Young’s modulus of the industrial hemp stem were non-homogenous within K fertilization treatments. The highest tensile strength (388.52 MPa) and Young’s modulus (32.09 GPa) were on K1 treatment. The lowest industrial hemp stem tensile strength was determined at K2 treatment (95.16 MPa), whereas stems in the control treatment had the lowest Young’s modulus (21.09 GPa). In the mixtures of hemp fibers with rammed earth, the higher compressive strength was determined on cubic samples than on cylindrical samples. This study contributes to the industrial hemp K fertilization of the newer genotypes, but there has been a lack of research in recent times. Since industrial hemp has great potential in various industry branches, this study also contributes to using fiber extracted from the stem in eco-friendly and renewable forms in mixtures with rammed earth.</jats:p
Prediction Models for Mechanical Properties of Cement-Bound Aggregate with Waste Rubber
No full textThe high stiffness of cement-bound aggregate (CBA) is recognized as its main drawback. The stiffness is described by the modulus of elasticity, which is difficult to determine precisely in CBA. Incorporating rubber in these mixtures reduces their stiffness, but mathematical models of the influence of rubber on the mechanical characteristics have not previously been defined. The scope of this research was to define a prediction model for the compressive strength (fc), dynamic modulus of elasticity (Edyn) and static modulus of elasticity (Est) based on the measured ultrasonic pulse velocity as a non-destructive test method. The difference between these two modules is based on the measurement method. Within this research, the cement and waste rubber content were varied, and the mechanical properties were determined for three curing periods. The Edyn was measured using the ultrasonic pulse velocity (UPV), while the Est was determined using three-dimensional digital image correlation (3D DIC). The influence of the amount of cement and rubber and the curing period on the UPV was determined. The development of prediction models for estimating the fc and Est of CBA modified with waste rubber based on the non-destructive test results is highlighted as the most significant contribution of this work. The curing period was statistically significant for the prediction of the Est, which points to the development of CBA elastic properties through different stages during the cement-hydration process. By contrast, the curing period was not statistically significant when estimating the fc, resulting in a simplified, practical and usable prediction model
Challenges in Ground-Penetrating Radar Application in Structural Elements: Determination of the Dielectric Constant of Glued Laminated Timber Case Study
No full textIn this paper, some of the basic information on Ground-Penetrating Radar (GPR), its applications (especially in the field of civil engineering) and limitations are presented. As a non-destructive technique, GPR is a powerful tool for the investigation of structures and structural members, roads, geological layers, archaeological sites and many more. The technology is based on electromagnetic radiation in the UHF/VHF range (10 MHz to 3 GHz). The choice of the frequency depends on the intended use, depth and size of the target and medium where the target is located. Joined with other testing methods (ultrasound method, dynamic methods with forced or ambient vibrations, electrical conductivity testing, etc.), GPR can provide a deep insight into the investigated object. However, like many other non-destructive methods, the choice of input parameters may affect the results. In this regard, a case study presented in this paper demonstrates not only different applications of GPR in civil engineering but also the determination (calibration) of one of those input parameters: the dielectric constant of glued laminated timber. The challenge here was not only to investigate the influence of the direction of measurements with regards to the direction of the fibers but also to acknowledge the contribution of the test antenna used during testing and dielectric constant calibration
The influence lines of statically indeterminate systems
No full textUtjecajne linije koriste se u proračunu konstrukcija koje su izložene djelovanju pokretnih opterećenja. Kod konstruiranja utjecajnih linija moramo voditi računa radi li se o statički određenom ili neodređenom sustavu. Na statički određenim sustavima utjecajne linije definiraju se kao linearne funkcije. Dok kod statički neodređenih sustava linije nisu pravci nego krivulje. Kroz primjere su prikazani postupci kojima se izvode proračuni utjecajnih linija za statički neodređene sustave. Konstrukcija utjecajnih linija na statički neodređenim sustavima objašnjena je na primjerima kontinuirane grede korištenjem metode sila i metode pomaka, koje su temeljne metode za rješavanje statički neodređenih sustava
Reconstruction of the water main PS - Vratno - VS Kalnik - VS Deklešanec
No full textCilj ovoga završnog rada je opisati uvjete rada magistralnog cjevovoda PS Vratno – VS Kalnik – VS Deklešanec te obrazložiti razloge zbog kojih je potrebna rekonstrukcija istog. Također opisati gradnju (rekonstrukciju) spomenutog magistralnog cjevovoda uz pravila struke, te ukazati na pravilno korištenje istih. Rekonstrukcijom će se omogućiti neometana vodoopskrba vodoopskrbnog podsustava Kalnik te samim time gospodarski i društveni razvoj. Stabilizirat će se pogonski uvjeti na tom dijelu vodoopskrbnog sustava, smanjiti učestala pojava kvarova na mreži (puknuća cjevovoda) koji uzrokuju izražene gubitke vode i privremene prekide u opskrbi vodom te tako osigurati neometana dobava potrebnih količina vode potrošačima. Magistralni cjevovod je u tijeku rekonstrukcije i bit će u cijelosti izgrađen od duktilnih cijevi promjera DN 150 te je projektiran za korištenje od minimalno 50 godina
Impacts of river regulation of meanders on hydraulic and morphologic characteristics of watercourse
No full textU diplomskom radu hidrauličkim proračunom i modeliranjem obrađena je dionica rijeke Vuke na području Laslovačkog meandra koji ima svoj početak na rkm 38+380, a završetak na rkm 36+567. Ulazni podaci su preuzeti sa Državnog hidrometeorološkog
zavoda za hidrološku postaju Beketinci za niz u trajanju od 21 godinu, počevši od 2000. godine, pa sve do 2022. godine, izuzevši 2009. i 2017. godinu. Odabrana postaja je prva hidrološka postaja uzvodno od Laslova. Na području Laslova ne postoji hidrološka postaja. Na temelju preuzetih podataka o protocima i vodostajima u razdoblju od 21 godine napravljen je hidraulički proračun protoka i vodostaja u programu Microsoft Office Excel prema nekoliko teorijskih i empirijskih funkcija raspodjele: Log Pearson III, Normalna distribucija, Čegodajeva metoda i Weibullova metoda. Poprečni presjeci za meandar su preuzeti iz Hrvatskih voda u .dwg formatu, dok su presjeci prokopa te uzvodne i nizvodne dionice kreirani prema zadanim shemama za određene dionice rijeke Vuke uz poznate nadmorske visine nasipa i dubine korita. Dobiveni rezultati hidrološkog proračuna metodom Log Pearson III koristili su se u računalnom programu HEC-RAS. Unosile su se dobivene vrijednosti protoka i odostaja za povratna razdoblja od 1, 2, 5, 10, 25, 50 i 100 godina. Napravljena su tri modela predmetne dionice. Jedan model predstavlja situaciju prije regulacijskih radova, a druga dva predstavljaju situaciju nakon izvedenih regulacijskih radova, što uključuje gradnju prokopa i preljevnih građevina (pregrada na meandru). Visine pregrada određene su na temelju desetogodišnjeg povratnog razdoblja za srednje godišnje vodostaje. Dobivene su simulacije vodostaja za navedena povratna razdoblja na temelju kojih se uspoređuju rezultati karakteristika strujanja.In this graduation thesis a section of the river Vuka, at the area of meandar near Laslovo, which begins on the route of a kilometer 38+380 and ends at the route of a kilometer 36+567, has been processed by hydraulic calculation and modeling. The input has been taken from the State Hydrometeorological Service (DMHZ) from hydrological station Beketinci for the period of 21 years ( 2000-2022), with the exception of 2009 and 2017. Selected hydrological station is the closest upstream station from Laslovo section. There is no hydrological station in the area of Laslovo. Based on the data taken over a period of 21 years, a hydraulic calculation of the flow and water level was made in Microsoft Office Excel according to several theoretical and empirical distribution functions: Log Pearson III, Normal distribution, Čegodaj method and Weibull method. Cross sections for meander section were used in .dwg format given by Croatian waters, while other cross sections, that belong to upstream and downstream sections, were created according to default schemes for specified sections of the Vuka river with known elevations of embakment heights and depths of the riverbed. The results of the hydrological calculations by method Log Pearson III were used in computer program HEC-RAS. The resulting flow and water level values for return periods of 1, 2, 5, 10, 25, 50 and 100 years were entered. Three models were made. One model presents the situation before the regulatory work and the other two models present the situation after the regulatory work, which includes the construction of canal and overflow structures (partition barriers). The heights of the partition barriers are determined on the basis of a ten years return period for mean annual water levels. Simulations of the water level for these return period were obtained, on the basis of which the results of the flow characteristics are compared