| | SLO | ENG | Cookies and privacy

Bigger font | Smaller font

Search the digital library catalog Help

Query: search in
search in
search in
search in
* old and bologna study programme

Options:
  Reset


1 - 10 / 57
First pagePrevious page123456Next pageLast page
1.
Razvoj metodologije za načrtovanje geotehničnih konstrukcij na podlagi verjetnosti porušitve in večnamenske optimizacije
Rok Varga, 2024, doctoral dissertation

Abstract: Zemljine in kamnine na mestu, kjer so zgrajeni geotehnični objekti, predstavljajo inženirju negotov element, saj začetno napetostno stanje, predhodne obremenitve in razbremenitve ter prekonsolidacija zemljin niso znane. Prav tako se lastnosti zemljin spreminjajo v vertikalni in horizontalni smeri. Za upoštevanje raznih negotovosti pa se za načrtovanje konstrukcij uporabljajo verjetnostne analize. Za namene, da bi lahko upoštevali to negotovost, smo v doktorski disertaciji razvili celovit pristop za optimalno načrtovanje geotehničnih konstrukcij na podlagi verjetnosti porušitve in stroškov gradnje, z osredotočenostjo na večnamensko optimizacijo. Kadar načrtujemo konstrukcijo na podlagi verjetnosti porušitve, pravimo pristopu verjetnostna analiza ali angleško reliability based design (RBD). Naša razvita metodologija za optimizacijo uporablja genetski algoritem, ki je kodiran z realnimi števili. V doktorski disertaciji smo analizirali številne metode, ki se uporabljajo pri načrtovanju geotehničnih konstrukcij na podlagi verjetnosti porušitve, pri čemer smo predstavili teoretična izhodišča in na primeru horizontalnega zdrsa točkovnega temelja pokazali njihovo kompleksnost. Tako imenovana »razširjena RBD metoda« se je izkazala za inženirjem najbolj prijazno metodo, saj poda kakovostnejše informacije o zasnovi in o porušitvenih mehanizmih. V vseh treh aplikativnih primerih geotehničnih konstrukcij, to so težnostni podporni zid, geotermalni pilot in vpeta vitka oporna konstrukcija, smo pridobili detajlne podatke o kritičnih pogojih nosilnosti za porušitev, kar omogoča inženirjem, da preprečijo specifičen porušitveni mehanizem z dotično spremembo zasnove. V tem smislu smo postavili tudi glavno tezo doktorske disertacije, in sicer, da je možno razviti učinkovito metodologijo za načrtovanje geotehničnih konstrukcij na podlagi verjetnosti porušitve in z večnamensko optimizacijo. Analize in primerjave z načrtovanjem geotehničnih konstrukcij v skladu z Evrokodom, ki upošteva delne količnike varnosti, pa so pokazale, da je razvita metodologija bolj občutljiva na vse spremenljivke in robne pogoje, kar omogoča celovitejšo obravnavo konstrukcij in privede do optimalnih zasnov danih konstrukcij. Tako je bil z razvojem in preizkušanjem metodologije potrjen potencial le-te za praktično uporabo v inženirski praksi, kar bi lahko omogočalo dodatno analizo konstrukcij za večjo zanesljivost in bolj ekonomično gradnjo geotehničnih konstrukcij.
Keywords: Verjetnost porušitve, optimizacija, genetski algoritem, geotermalni piloti, geotehnične konstrukcije
Published in DKUM: 19.12.2024; Views: 0; Downloads: 24
.pdf Full text (5,60 MB)

2.
Cost effectiveness of chip seal and hot mix asphalt pavements
Bojan Žlender, Cahit Gürer, Rok Varga, Primož Jelušič, 2024, original scientific article

Abstract: Chip seal pavements, consisting of one or more layers of asphalt binder and fine aggregate, can be mechanically characterized as a surface treatment that enhances evenness and trafficability. This paper examines the geotechnical aspects of chip seal applicability compared to traditional hot mix asphalt pavements. An analytical model was employed to design unpaved roads and determine the required thickness of unbound layers. Eight optimization models were developed for hot mix asphalt pavements and four for chip seal pavements, aimed at achieving optimal designs for various input parameters. These outcomes were used to conduct a multi-parametric analysis, incorporating an optimization loop for each combination of design variables. The results indicate that, under low traffic conditions, a chip seal pavement structure can be up to 40% less expensive than an optimal hot mix asphalt pavement structure, particularly when the subgrade has low bearing capacity and is exposed to unfavorable climatic conditions. However, at medium traffic loads, with good subgrade bearing capacity and favorable climate, the chip seal pavement structure incurs costs that are 25% higher than those of the hot asphalt pavement structure. In addition, chip seal pavements should always be designed with integrated geosynthetic reinforcement to minimize construction costs, and chip seal is not as sensitive to frost as hot mix asphalt.
Keywords: chip seal, hot mix asphalt, pavement design, cost optimization
Published in DKUM: 10.12.2024; Views: 0; Downloads: 5
.pdf Full text (2,91 MB)
This document has many files! More...

3.
Optimization of embedded retaining walls under the effects of groundwater seepage using a reliability-based and partial factor design approach
Rok Varga, Bojan Žlender, Primož Jelušič, 2024, original scientific article

Abstract: In this paper, a comparative analysis of the effects of groundwater, seepage and hydraulic heave on the optimal design of embedded retaining walls is carried out. The optimization model for an optimal retaining wall (ORW) minimizes the total length of the retaining wall considering design constraints. The model is extended to include the probability of failure as an additional constraint. This overcomes the limitations of the partial safety factor approach, which does not fully account for uncertainties in the soil. In contrast, the reliability-based design (RBD) approach integrates these uncertainties and enables an assessment of the impact of seepage and hydraulic heave on the reliability of the structure. A real-coded genetic algorithm was used to determine optimal designs for both optimization methods. The results of the case study show that the addition of seepage (groundwater flow) to the hydrostatic conditions has a modest effect on the embedment depth. The design based on partial safety factors, which takes seepage into account, leads to a slight increase in the embedment depth of 0.94% compared to a retaining wall design that only takes the hydrostatic conditions of the groundwater into account. When designing on the basis of probability failure, the percentage increase in embedment depth due to seepage is between 2.19% and 6.41%, depending on the target probability of failure. Furthermore, the hydraulic heave failure mechanism did not increase the required embedment depth of the retaining wall, which means that the failure mechanism of rotation near the base was decisive for the design.
Keywords: embedded retaining wall, reliability-based design, partial safety factor design, optimization, genetic algorithm
Published in DKUM: 10.12.2024; Views: 0; Downloads: 4
.pdf Full text (2,13 MB)
This document has many files! More...

4.
Sustainable retaining wall solution as a mitigation strategy on steep slopes in soft rock mass
Primož Jelušič, Goran Vlastelica, Bojan Žlender, 2024, original scientific article

Abstract: Steep slopes in soft rock are characterized by their susceptibility to instability (rockfall, rockslide) due to weathering and erosion of the slope surface. This article deals with the problem of adapting to the increasing height of the scree slope. The construction of a retaining wall in a scree slope in front of a slope of soft rock with a steep face, where a very rapid weathering and erosion process of weathered material takes place, and the simultaneous deposition of material in front of the steep slope is a common solution. Changes in the geometry of the slope and the front scree are taken into account, and at the same time, sufficient safety against rockfall must be ensured. The analysis is shown on a specific example of a steep flysch slope near Split, Dalmatia. The retaining wall solutions are compared in terms of function, cost and sustainability. The construction of a single colossal, reinforced concrete retaining wall shows that this solution is not feasible due to the high construction costs and CO2 emissions of the retaining wall. A model was therefore developed to determine the height of the retaining walls for different construction time intervals and distances from the original rock face. The critical failure modes were investigated for various retaining wall solutions with regard to the highest degree of utilization of the resistance, which also allows the cost-optimized solutions to be determined. By building two or more successive retaining walls at suitable intervals and at an appropriate distance from the original rock face, construction costs and CO2 emissions can be significantly reduced.
Keywords: retaining wall, erosion, rockfall, steep slope, flysch, sustainable design, cost optimization
Published in DKUM: 09.12.2024; Views: 0; Downloads: 7
.pdf Full text (6,06 MB)
This document has many files! More...

5.
Sanacija zemeljskega plazu s kamnito zložbo v občini Luče
Domen Ošep, 2024, undergraduate thesis

Abstract: V diplomski nalogi je predstavljen postopek sanacije plazu s podporno kamnito zložbo. Plaz je nastal kot posledica avgustovskih poplav leta 2023 v občini Luče. Diplomska naloga opisuje vrste zemeljskih plazov in podrobno opiše vzrok za nastanek plazu v občini Luče ter mehanizem porušitve. Opisana je vsebina geološko geotehničnega poročila na podlagi katerega je bila izvedena geotehnična analiza kamnite zložbe. Geomehanske lastnosti temeljnih tal so bile določene na podlagi nekaterih terenskih in laboratorijih preiskav. Geotehnična analiza je bila izvedena skladno s standardi Evrokod. Podan je postopek izvedbe kamnite zložbe vključno z opisom osnovnih materialov in tehnologije gradnje. Podan je tudi popis del za izgradnjo kamnitega podpornega zidu. Diplomska naloga torej prikazuje ključne postopke za izvedbo sanacije plitvega zemeljskega plazu.
Keywords: plaz, sanacija, kamnita zložba, geotehnično poročilo, geotehnična analiza
Published in DKUM: 14.11.2024; Views: 0; Downloads: 30
.pdf Full text (1,58 MB)

6.
Enhancing sustainability of building foundations with efficient open-end pile optimization
Primož Jelušič, 2024, original scientific article

Abstract: Optimizing open-end piles is crucial for sustainability as it minimizes material consumption and reduces environmental impact. By improving construction efficiency, less steel is needed, reducing the carbon footprint associated with production and transportation. Improved pile performance also results in more durable structures that require less frequent replacement and maintenance, which in turn saves resources and energy. This paper presents a parametric study on optimal designs for open-ended piles in sand, presenting a novel approach to directly compute optimal pile designs using CPT results. It addresses challenges posed by soil variability and layered conditions, with the optimization model accounting for interdependencies among pile length, diameter, wall thickness and soil properties, including the pile–soil plug system. A mixed-integer optimization model OPEN-Pile was developed, consisting of an objective function for pile mass and CO2 emissions. The objective function was constrained by a set of design and geotechnical conditions that corresponded to current codes of practice and recommendations. The efficiency of the developed optimization model is illustrated by two case studies. In the case of Blessington sand, the calculation results show that it is more economical and environmentally friendly to increase the pile diameter and pile wall thickness than the pile length. In efficient design, the ratio between diameter and wall thickness is calculated at the upper limit. For the optimum design of piles in Blessington sand, the optimum ratios of pile length to diameter, diameter to wall thickness and length to wall thickness are 5, 50 and 250, respectively. In a layered soil profile, the decision of where to place the pile base depends on the resistance of the cone tip and the thickness of the individual layers. To determine in which layer the pile base should be placed, we need to perform an optimization for the given design data.
Keywords: open-ended pile, computational modeling, structural optimization
Published in DKUM: 03.09.2024; Views: 49; Downloads: 10
.pdf Full text (3,45 MB)
This document has many files! More...

7.
Zasnova in analiza nosilne konstrukcije večnamenskega stadiona : magistrsko delo
Mitja Beber, 2024, master's thesis

Abstract: V magistrskem delu je obravnavana zasnova, statična in potresna analiza ter dimenzioniranje nosilne konstrukcije večnamenskega stadiona s tlorisnimi dimenzijami 50,3 m x 14,3 m. Kapaciteta tribune je približno 1000 sedežev. Tribuna je v celoti prekrita z enokapno streho, ki dosega maksimalno višino 12,7 m v slemenu. Medetažne konstrukcije so predvidene iz prednapetih betonskih votlih plošč, ter na tribunskem delu iz montažnih armirano betonskih tribunskih L-elementov. Izvedena je bila analiza vplivov na konstrukcijo in potresna analiza v skladu s standardoma SIST EN 1991 in SIST EN 1998. Jeklena konstrukcija je bila dimenzionirana v skladu s standardom SIST EN 1993, dimenzioniranje točkovnih temeljev smo opravili v skladu s standardom SIST EN 1997. S pomočjo programske opreme Scia Engineer je izvedena statična in potresna analiza ter dimenzioniranje jeklenih elementov. Za analizo in dimenzioniranje spojev je bil uporabljen program Idea Statica. V magistrskem delu je izvedena tudi analiza porabe materiala in prikaz stroškov izdelave nosilne konstrukcije objekta.
Keywords: gradbeništvo, jeklene konstrukcije, stadion, statična analiza, potresna analiza, dimenzioniranje
Published in DKUM: 13.08.2024; Views: 84; Downloads: 46
.pdf Full text (13,68 MB)

8.
Sustainable design of circular reinforced concrete column sections via multi-objective optimization
Primož Jelušič, Tomaž Žula, 2023, original scientific article

Abstract: An optimization model for reinforced concrete circular columns based on the Eurocodes is presented. With the developed optimization model, which takes into account the exact distribution of the steel reinforcement, which is not the case when designing with conventional column design charts, an optimal design for the reinforced concrete cross section is determined. The optimization model uses discrete variables, which makes the results more suitable for actual construction practice and fully exploits the structural capacity of the structure. A parametric study of the applied axial load and bending moment was performed for material cost and CO2 emissions. The results based on a single objective function show that the optimal design of the reinforced concrete column cross section obtained for the material cost objective function contains a larger cross-sectional area of concrete and a smaller area of steel compared with the optimization results when CO2 emissions are determined as the objective function. However, the optimal solution in the case where the material cost was assigned as the objective function has much more reserve in axial load capacity than in the optimal design where CO2 was chosen as the objective function. In addition, the multi-objective optimization was performed to find a set of solutions that provide the best trade-offs between the material cost and CO2 emission objectives.
Keywords: reinforced concrete columns, circular cross section, costs, CO2 emissions, multi-objective optimization, genetic algorithm
Published in DKUM: 15.04.2024; Views: 338; Downloads: 209
.pdf Full text (4,56 MB)
This document has many files! More...

9.
Statična in dinamična analiza jeklenega visečega mostu v Renkah : magistrsko delo
Nik Poglajen, 2024, master's thesis

Abstract: Magistrska naloga obravnava statično in dinamično analizo mostu Renke, ki je bil zgrajen leta 1991 z namenom omogočanja prehoda ljudi iz naselja do železniške postaje na nasprotni strani reke Save. Danes so na mostu vidne poškodbe, vključno s preperelimi deskami, odpadanjem barve in rjavečimi jeklenimi elementi, ki so posledica pomanjkanja rednega vzdrževanja. Analiza mostu je narejena s pomočjo programa SCIA Engineer, z uporabo linearne in nelinearne teorije. Pri analizi so upoštevani standardi iz družine Evrokod 1, 2, 3, 7 in 8. Preverjeni so tako jeklena konstrukcija mostu kot tudi betonski temelji. Most je opisan kot viseči most, pri čemer se glavna jeklenica naslanja na dva pilona, ki sta postavljena na obeh straneh mostu in sta zasnovana v obliki črke A. Glavna jeklenica je sidrana v zaledje s težnostnim zidom in geotehničnimi sidri. Širina mostu znaša 1,62 m, glavni razpon meri 72 m, stranska razpona pa 15 m in 10 m. Na glavno jeklenico so simetrično pritrjene vešalke, ki zagotavljajo oporo glavnemu L-nosilcu in horizontalnemu povezju s hrastovimi deskami. Glavni cilj magistrske naloge je primerjava rezultatov analize mostu Renke med standardom JUS in sodobnim evropskim standardom Evrokod. Analiza kaže, da Evrokod v nekaterih primerih prinaša bistveno drugačne rezultate od standarda JUS, deloma tudi zaradi uporabe različnih materialnih parametrov. Ta primerjava omogoča boljše razumevanje vpliva standardov na varnost in zmogljivost mostu ter poudarja pomen uporabe aktualnih standardov pri načrtovanju in vzdrževanju infrastrukture.
Keywords: viseči most, jeklo, primerjava standardov JUS in EC, statična analiza, dinamična analiza
Published in DKUM: 16.02.2024; Views: 536; Downloads: 103
.pdf Full text (11,46 MB)

10.
Analiza posedkov in napetosti geotermalnih pilotov : magistrsko delo
Mitja Madjar, 2023, master's thesis

Abstract: V magistrski nalogi obravnavamo določitev posedkov geotermalnih pilotov in osnih napetosti zaradi mehanske in termalne obremenitve. V teoretičnem delu smo opisali geotermalno energijo, vrste geotermalnih konstrukcij in navedli nekaj primerov iz prakse. V računskem delu pa smo izračunali vertikalno nosilnost pilota z metodo, ki jo je podal Berezantzev. Posedek zaradi mehanske obremenitve pa smo izračunali po metodi, ki jo je razvil Poulos. Izračunali smo tudi posedek pilota zaradi temperaturne obremenitve in analizirali vpliv spremembe temperature v različnih zemljinah in glede na dolžino pilota. Analiza kaže na to, da je vpliv spremembe temperature na geotermalni pilot manjši v primerjavi z mehansko obremenitvijo na pilot, vendar ga ne smemo zanemariti, predvsem v drobnozrnatih zemljinah.
Keywords: geotermalna energija, geotermalne konstrukcije, geotermalni piloti, posedki
Published in DKUM: 20.09.2023; Views: 439; Downloads: 42
.pdf Full text (2,77 MB)

Search done in 0.3 sec.
Back to top
Logos of partners University of Maribor University of Ljubljana University of Primorska University of Nova Gorica