1. Optimal design and competitive spans of timber floor joists based on multi-parametric MINLP optimizationPrimož Jelušič, Stojan Kravanja, 2022, original scientific article Abstract: This study investigates the optimization of the design of timber floor joists, taking into
account the self-manufacturing costs and the discrete sizes of the structure. This non-linear and
discrete class of optimization problem was solved with the multi-parametric mixed-integer non-linear
programming (MINLP). An MINLP optimization model was developed. In the model, an accurate
objective function of the material and labor costs of the structure was subjected to design, strength,
vibration and deflection (in)equality constraints, defined according to Eurocode regulations. The
optimal design of timber floor joists was investigated for different floor systems, different materials
(sawn wood and glulam), different load sharing systems, different vertical imposed loads, different
spans, and different alternatives of discrete cross-sections. For the above parameters, 380 individual
MINLP optimizations were performed. Based on the results obtained, a recommended optimal
design for timber floor joists was developed. Engineers can select from the recommendations the
optimal design system for a given imposed load and span of the structure. Economically suitable
spans for timber floor joists structures were found. The current knowledge of competitive spans for
timber floor joists is extended based on cost optimization and Eurocode standards.
Keywords: structural optimization, cost optimization, discrete optimization, mixed-integer nonlinear programming, MINLP, timber floor joists
Published in DKUM: 12.03.2025; Views: 0; Downloads: 1
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2. The MINLP approach to topology, shape and discrete sizing optimization of trussesSimon Šilih, Zdravko Kravanja, Stojan Kravanja, 2022, original scientific article Abstract: The paper presents the Mixed-Integer Non-linear Programming (MINLP) approach to the
synthesis of trusses. The solution of continuous/discrete non-convex and non-linear optimization
problems is discussed with respect to the simultaneous topology, shape and discrete sizing optimization of trusses. A truss MINLP superstructure of different topology and design alternatives
has been generated, and a special MINLP model formulation for trusses has been developed. In the
optimization model, a mass objective function of the structure has been defined and subjected to
design, load and dimensioning constraints. The MINLP problems are solved using the Modified
Outer-Approximation/Equality-Relaxation (OA/ER) algorithm. Multi-level MINLP strategies are introduced to accelerate the convergence of the algorithm. The Modified Two-Phase and the Sequential
Two-Phase MINLP strategies are proposed in order to solve highly combinatorial topology, shape
and discrete sizing optimization problems. The importance of local buckling constraints on topology
optimization is also discussed. Some simple numerical examples are shown at the end of the paper to
demonstrate the suitability and efficiency of the proposed method.
Keywords: structural synthesis, topology optimization, discrete sizing optimization, mixed-integer non-linear programming, MINLP, modified OA/ER algorithm, multi-level MINLP strategies, steel structures, trusses
Published in DKUM: 11.03.2025; Views: 0; Downloads: 3
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3. QLCM Method for Determining the Quality Level of Circular Movement in Floor Plans of Houses and ApartmentsKaja Pogačar, Stojan Kravanja, 2025, original scientific article Abstract: This article deals with the specific spatial organization of residential buildings and highlights the advantages of ‘floor plans with circular paths’. When renovating the existing floor plans of houses or apartments, different floor plan variants can be designed that enable circular movement. Choosing the best variant is sometimes a difficult process. For this purpose, the so-called QLCM method (quality level of circular movement) was developed, which makes it possible to calculate the quality level of the adapted floor plan variants in terms of circular movement. The method covers the aspects of movement and visibility. Different path types, such as the path from room to room, door to door, door to window, and the path along the outer walls are analyzed. Different types of views such as single, multiple, and wide views are examined. Using the QLCM method, a special quality-level coefficient is calculated for each modified floor plan. The variant with the highest calculated coefficient can be selected for implementation. Based on case studies of converting three typologically different apartments/houses from non-circular to circular floor plans, the benefits in terms of enabling circular movement, increasing visual distance, and the perception of the size of the housing unit are demonstrated.
Keywords: residential buildings, floor plan, spatial organization, renovation, circular movement, path, viev, QLCM method, movement aspect, visual aspect
Published in DKUM: 28.02.2025; Views: 0; Downloads: 4
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4. Development of Methodology for Estimation of Energy-Efficient Building Renovation Using Application of MINLP-Optimized Timber–Glass Upgrade ModulesMaja Lešnik Nedelko, Stojan Kravanja, Miroslav Premrov, Vesna Žegarac Leskovar, 2025, original scientific article Abstract: Vertical addition to already-existing structures is an approach to energy-efficient building renovation. It presents an opportunity for the densification of built-up areas and the construction of new usable spaces. While many studies have dealt with the subject of renovating buildings with a focus on energy efficiency, far fewer studies have specifically examined the potential of vertically extending existing buildings, an approach which could be introduced in new sustainable building policies. The objective of this study is to redevelop optimal timber–glass upgrade modules, considering the ideal proportions of glazing for all cardinal directions, by using discrete Mixed-Integer Non-Linear Programming optimization. The novelty of the suggested method resides in the synchronous optimization of the upgrade modules’ daylighting and energy-efficiency performance, resulting in the creation of optimization methods that can determine the optimal glazing proportions for all cardinal directions and incorporate rational design and window measurement. The impact of the developed Mixed-Integer Non-Linear Programming-optimized upgrade modules is compared to previously designed optimized upgrade modules. Finally, a methodology for estimating the energy efficiency of building renovations incorporating vertical additions using the timber–glass upgrade modules was developed, supporting the quick assessment of the reduction in hybrid buildings’ energy consumption for heating and cooling according to boundary conditions, presuming that they undergo the suggested renovations. The findings are applicable (not exclusively) to Slovenia’s residential building stock, which makes up around 20% of the country’s current housing stock and was mainly constructed between 1946 and 1970. This offers a substantial opportunity to improve the overall sustainability and energy efficiency of the country’s housing stock. The proposed approach offers a holistic solution to drive sustainable development in the built environment by incorporating all three pillars of sustainability (environmental, social, and economic).
Keywords: energy efficient building renovation, energy efficiency, building vertical addition, timber–glass upgrade modules, mixed-integer non-linear programming, MINLP, optimization, visual comfort, energy sustainability
Published in DKUM: 16.01.2025; Views: 0; Downloads: 5
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5. Priročnik za delo s programom PIPEOPT-SR za optimiranje visokotlačnih jeklenih cevovodov z ojačitvamiStojan Kravanja, Tomaž Žula, 2024, manual Abstract: Pričujoči priročnik obravnava delo s programom – optimizacijskim modelom - za optimiranje visokotlačnih jeklenih cevovodov z ojačitvami, kakršni se vgrajujejo v izvrtan tunel v hribino. Cevovod je dimenzioniran kot samonosilna jeklena cilindrična lupina s krožnimi ojačitvami brez sodelovanja hribine in okoliškega betona. Cevovod je lahko obremenjen z notranjim ali zunanjim tlakom. Optimizacija cevovoda se izvede z nelinearnim programiranjem, NLP. V ta namen je bil modeliran optimizacijski program PIPEOPT-SR, verzija 1,0. Optimizacijski model vsebuje skalarje (vhodne podatke), spremenljivke in namensko funkcijo mase jeklene konstrukcije, ki je podvržena sistemu pogojnih (ne)enačb iz statične analize in dimenzioniranja cevovoda v skladu s C.E.C.T. priporočili. Na koncu priročnika je predstavljen primer optimizacije visokotlačnega cevovoda z ojačitvami črpalne hidroelektrarne Kozjak, locirane v bližini Maribora.
Keywords: program, optimizacijski model, optimizacija, nelinearno programiranje, visokotlačni jekleni cevovod z ojačitvami
Published in DKUM: 19.12.2024; Views: 0; Downloads: 22
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6. Priročnik za delo s programom za optimiranje sovprežnega stropnega sistema s plastično odpornostjo nosilca z jeklenimi IPE profili : COMBOPT-PIPE, verzija 1,0Tomaž Žula, Stojan Kravanja, 2024 Abstract: Priročnik predstavlja delo s programom za optimiranje sovprežnega stropnega sistema, ki se lahko uporablja pri gradnji večetažnih stavb. Konstrukcija je sestavljena iz armiranobetonske plošče in jeklenih IPE nosilcev. Optimiranje je izvedeno z mešanim celoštevilskim nelinearnim programiranjem (MINLP). Razvit je bil optimizacijski model COMBOPT-PIPE s podrobno namensko funkcijo lastnih izdelavnih stroškov. Poleg namenske funkcije optimizacijski model vsebuje vhodne podatke, spremenljivke, pogojne (ne)enačbe, poznane iz analize in dimenzioniranja sovprežnih konstrukcij, celoštevilske in mešane celoštevilske pogojne (ne)enačbe. Pogoji dimenzioniranja so definirani v skladu z Evrokod 4. Na koncu priročnika je predstavljen računski primer optimizacije sovprežnega stropnega sistema.
Keywords: program, optimizacijski model, optimizacija, mešano celoštevilsko nelinearno programiranje, sovprežni stropni sistem
Published in DKUM: 22.11.2024; Views: 0; Downloads: 21
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7. Zasnova in analiza nosilne konstrukcije večnamenskega stadiona : magistrsko deloMitja 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: 60
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8. Statična in dinamična analiza jeklenega visečega mostu v Renkah : magistrsko deloNik 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: 111
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9. Analiza odpornosti jeklene hale z mostnim žerjavom na lokaciji z visoko nadmorsko višino : diplomsko deloDanilo Prelević, 2023, undergraduate thesis Abstract: V svojem diplomskem delu smo se posvetili analizi jeklene hale z vključeno žerjavno progo, pri čemer sem zajel statično analizo. Konkretno smo preučevali konstrukcijo jeklene hale, katere dimenzije znašajo 48,0 m x 25,0 m, z višino 10,0 m. Za izvedbo analize smo izhajail iz določenih dimenzij hale in specifikacij mostnega žerjava. Uporabili smo jeklo kakovosti S 355. V okviru naloge smo izvedli dimenzioniranje jeklene konstrukcije, talne plošče in tudi temelje. Dimenzije temelja so 2,5 m x 2,5 m, izdelan pa je bil iz armiranega betona C 25/30, pri čemer smo uporabili armaturo tipa B 500. Pri izračunih smo upoštevali obremenitve, ki jih povzročajo sneg, veter, delovanje žerjava ter potres, skladno s predpisi SIST EN 1990-1998. Kot zaključek naloge smo tudi predstavili količino porabljenega jekla ter strošek za izdelavo jeklene hale.
Keywords: gradbeništvo, jeklene konstrukcije, žerjavna proga, dimenzioniranje.
Published in DKUM: 19.09.2023; Views: 567; Downloads: 78
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10. Primerjava med protipožarnim premazom in požarno odpornimi ploščami pri analizi požarne odpornosti jeklene hale : diplomsko deloŽiga Lugarič, 2023, undergraduate thesis Abstract: V diplomskem delu smo primerjali učinkovitost dveh pasivnih protipožarnih zaščit, in sicer protipožarnih premazov in požarno odpornih plošč. To smo naredili tako, da smo te aplicirali na jekleno halo dimenzij 10 × 20 m in jo dimenzionirali na projektno požarno stanje R60 z uporabo EUROCODE standardov. Ugotovili smo, da se s protipožarnimi premazi objekt poruši zaradi prevelike temperature jekla. Medtem se pa jeklo pri uporabi požarno odpornih plošč segreje na bistveno nižjo temperaturo in s tem ne pride do porušitve. Primerjava med obema sistemoma poudarja pomembnost pravilne izbire protipožarne zaščite ob upoštevanju specifičnosti konstrukcije. Diplomsko delo predstavlja teoretično znanje v praktični uporabi ter ponuja dodatne informacije pri izbiri zaščite za prihodnje projekte.
Keywords: gradbeništvo, znanstveno delo, pasivna protipožarna zaščita, požar
Published in DKUM: 08.09.2023; Views: 524; Downloads: 60
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