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Engineering properties of tropical clay and bentonite modified with sawdust
Isaac I. Akinwumi, Oluwapelumi O. Ojuri, Adebanji S. Ogbiye, Colin A. Booth, 2017, izvirni znanstveni članek

Opis: Construction engineers typically avoid the use of expansive soils as construction materials because they are usually difficult to work on and can cause structural failure. This research work investigates how the application of sawdust to tropical clay and bentonite influences their geotechnical properties in order to determine their suitability for use as landfill-liner materials for the effective containment of toxic substances from landfills. X-ray diffractometry, X-ray fluorescence spectroscopy and scanning electron microscopy were used to determine the mineralogical composition, oxide composition and microstructure, respectively, of the clay and the bentonite. A series of laboratory tests were conducted to determine the specific gravity, Atterberg limits, compaction, unconfined compressive strength and permeability characteristics of the clay and the bentonite for varying proportions of sawdust application. Generally, increasing the percentage of sawdust caused a reduction in its specific gravity, maximum dry unit weight and unconfined compressive strength, while it caused an increase in the optimum moisture content and permeability of the modified clay and bentonite. The clay and bentonite both have a sufficiently low permeability that satisfies the hydraulic conductivity requirement for use as clay liners. Eight percent sawdust application to a clay having similar properties as that in this study is recommended as an economic way of modifying it – with the potential of improving its adsorbent property – for use in landfill-liner systems in order to prevent the toxic substances leaching from the landfills, thereby protecting the environment and public health.
Ključne besede: geotechnical properties, hydraulic barrier, landfill, construction, soil improvement, sustainability
Objavljeno: 18.06.2018; Ogledov: 376; Prenosov: 30
.pdf Celotno besedilo (766,16 KB)
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The degree of deterioration of the tunnels of the Prague Metro based on a monitoring assessment
Ivan Vaníček, Martin Vaníček, 2007, izvirni znanstveni članek

Opis: Understanding the ageing of structures is a very important issue from the point of view of assessing the risk inherent in those structures. Geotechnical structures, of course, have their own specific risks. This paper is focused on the tunnels of the Prague Metro, looked at from various aspects, i.e., geology, construction systems, and the influence of flooding. The section of the tunnels that was selected for monitoring is one of the most affected, and has a large system of cracked segments. However, even for this affected section the monitoring systems, based on macro- and micro-approaches, showed no significant deterioration was taking place. Nevertheless, for long-term monitoring a wireless system for data collection and transfer was installed and implemented. The results so far have been very positive.
Ključne besede: tunnel, metro, deterioration, ageing, geology, construction, monitoring assessment, MEMS, geophysical, wireless data transfer, metro flooding
Objavljeno: 18.05.2018; Ogledov: 708; Prenosov: 32
.pdf Celotno besedilo (1,21 MB)
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Back analysis of time-dependet displacement at the Trojane tunnel construction
Jakob Likar, 2004, izvirni znanstveni članek

Opis: The 2,900-metre double tube tunnel of Trojane forms part of the highway section between Celje and Ljubljana and part of the highway road system connecting Lendava and Koper with adjacent roads. The construction of this section, which is of special importance for the Republic Slovenia, has been going on for almost ten years. The highway near Trojane where the tunnel is located, lies on a hilly terrain composed of Permian-carboniferous rocks, which are tectonically badly damaged in some places and marked with broad fault zones, containing tectonically remoulded soil of low strength in terms of deformability properties. Even though the amount of waters coming from the hills during the excavation of the tunnel was relatively small, this water, in combination with extremely damaged weak rock caused the increase of deformations at the construction site. Geological and geotechnical surveying with geometric monitoring and the analyses of stress and deformation changes in the surrounding rocks and support elements were critical in assessing the actual weak-rock conditions during the course of construction. Since the analyses of deformation processes, which had been modelled with PLAXIS 3D TUNNEL PROGRAM, showed great impact on permanent stability of the tunnel, special care was paid to rheological changes in the surrounding rocks and combined in-built support elements. 3D back analyses with SOFT-SOIL-CREEP (SSC) constitutive model, which takes into account rheological phenomena, were carried out. The calculations of primary and secondary stresses and deformations were made for two characteristic areas and determined on the basis of realistic geological mapping during tunnel construction. The first area represented typical rocks of the Trojane tunnel, i.e. shales and siltstone, while the second one was a tectonic zone where geological and geotechnical conditions during excavation were less favourable. The results of back analyses used provided an acceptable possibility for estimating the stress-strain variation during construction as well as an appropriate basis for analysing vertical displacements at the tunnel roof. The calculation results show good correlation with field measurements.
Ključne besede: tunnels, construction, permain-carboniferous rocks, geological-geotechnical conditions, tunnel support, Trojane tunnel, finite element method, costitutive models, back analyses, field mesurement, time dependent analysis
Objavljeno: 15.05.2018; Ogledov: 588; Prenosov: 37
.pdf Celotno besedilo (868,88 KB)
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Survey of accomplishments in BIM implementation in Croatia, the Czech Republic, Germany, and Slovenia
Mario Galić, Vaclav Venkrbec, Franziska Chmelik, Immo Feine, Zoran Pučko, Uroš Klanšek, 2017, izvirni znanstveni članek

Opis: Building information modelling (BIM) may currently be considered the fastest developing concept in the field of construction management, aiming to become a global standard. Although the roots of the concept date back to the mid-1970s, some original expectations are still missing from its implementation. There has been a time gap between its theoretical and practical implementations. While the simultaneous development of information technologies is one reason for the implementation delay, other reasons remain unclear. This paper analyzes the gaps between theoretical and practical BIM application, as well as the legislation regarding BIM implementation in four countries (in alphabetical order: Croatia, the Czech Republic, Germany, and Slovenia). The paper additionally presents a survey of current practical BIM applications as well as general and theoretical feedback from construction projects that implemented BIM.
Ključne besede: construction industry, implementation, project management, survey
Objavljeno: 12.01.2018; Ogledov: 668; Prenosov: 237
.pdf Celotno besedilo (694,12 KB)
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Heuristics for NP-hard optimization problems
Janez Žerovnik, 2015, izvirni znanstveni članek

Opis: We provide several examples showing that local search, the most basic metaheuristics, may be a very competitive choice for solving computationally hard optimization problems. In addition, generation of starting solutions by greedy heuristics should be at least considered as one of very natural possibilities. In this critical survey, selected examples discussed include the traveling salesman, the resource-constrained project scheduling, the channel assignment, and computation of bounds for the Shannon capacity.
Ključne besede: optimization, metaheuristics, local search, greedy construction, traveling salesman problem
Objavljeno: 17.11.2017; Ogledov: 637; Prenosov: 117
.pdf Celotno besedilo (709,68 KB)
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Application of "Einstein's riddle" in solving construction machine allocation problems
Borna Dasović, Marko Čorak, Mario Galić, Uroš Klanšek, 2016, izvirni znanstveni članek

Opis: “Einstein’s riddle” is a popular example of constraints satisfaction problem. Since its introduction, different forms and variations of the riddle have been presented. Regardless of the variant of the riddle, its solution is considered a tough challenge for humans. Researchers have developed and are still developing mathematical models, as well as computational simulation models for solving it. In this article, the authors have modified a previously published mathematical model and developed a computational spreadsheet model for solving the riddle, which provides a unique solution for the riddle. The model was also tested in a small and medium-scaled form for solving constraint satisfaction problems regarding the allocation of construction machines. The authors have also highlighted the model’s limitations for solving such problems and made suggestions regarding necessary modifications in the model to solve more complex problems in the same domain.
Ključne besede: Einstein's riddle, zebra riddle, construction, machine allocation, combinatorial optimization
Objavljeno: 02.08.2017; Ogledov: 575; Prenosov: 338
.pdf Celotno besedilo (437,45 KB)
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Mixed-integer nonlinear programming based optimal time scheduling of construction projects under nonconvex costs
Rok Cajzek, Uroš Klanšek, 2016, izvirni znanstveni članek

Opis: Optimal project scheduling under nonconvex time-cost relations represents a challenging problem in construction management. The nonconvex time-cost relations may appear in a construction project when several different duration options are available for its activities due to alternative technological processes enabled for their realization or wide accessibility of production resources. The source of nonconvexity of the project scheduling optimization problem can also be the project penalty- or bonus-duration relations arranged within the construction contract. The aim of this paper is to present the mixed-integer nonlinear programming (MINLP) based optimal time scheduling of construction projects under nonconvex costs. For this purpose, the MINLP model was developed and applied. A numerical example from literature and an example of construction project time-cost trade-off analysis under practical nonconvex penalty function are given in the paper to demonstrate advantages of MINLP optimization. The example from literature first presented the capability of the MINLP approach to obtain the optimal solution for difficult, highly combinatorial nonconvex discrete project scheduling problem. Thereupon, the following example revealed that the optimal project time-cost curve may take very nonuniform shape on account of discrete nature of activity direct cost options and nonconvex relation between project duration and total cost. In this way, the presented study intends to provide practitioners with new information from the field of optimization techniques for project scheduling as well as an alternative view on performance of total cost when project duration is changed.
Ključne besede: extreme environments, construction management, discrete optimization, mixed-integer nonlinear programming, nonconvex costs, time scheduling
Objavljeno: 12.07.2017; Ogledov: 674; Prenosov: 311
.pdf Celotno besedilo (807,33 KB)
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Water museum on Skadar Lake
Nina Abramović, 2017, magistrsko delo

Opis: This Master’s Dissertation offers an idea project regarding a water museum at Lake Skadar. The idea emerged from a “Spatial Plan with Special Purposes for the National Park at Lake Skadar.” The project focuses on social and economic aspects: water is an influential part of the design and purpose of the facility. Through the project is established primarily for reconstruction and landscaping of the urban area around Lake Skadar, the concept and the design of the museum as a floating facility emphasize the importance of water to preserve both the natural environment and humanity. The architectural concept relies on a contemporary approach to museology, focusing on the features of the museum that a visitor can experience through a tour of the premises whereby each exhibit activates a particular sense. Architecture plays an important role in creating facilities intended for public use and education. The design of this facility offers a specific and unusual experience: rooms with experiences where water has a primary role, an educational area, and a completely cultivated access terrain for walking and relaxation. The project objective is to raise awareness and teach visitors about the importance of water, and to inspire them to experience water in unique, poetic way. Hopefully, it will motivate people to improve the environment in which they live.
Ključne besede: Water, museum, Skadar Lake, floating construction, human sense, new museology, tourism
Objavljeno: 28.06.2017; Ogledov: 845; Prenosov: 231
.pdf Celotno besedilo (64,35 MB)

Model for optimal project portfolio for the construction of railway infrastructure on corridors V and X
Anton Hauc, Majda Bastič, Lidia Jurše, Mirko Pšunder, 2010, kratki znanstveni prispevek

Opis: The construction of railway infrastructure should be dealt with as a national strategic developmental programme, which due to technical, geographical, logistical, and other requirements is carried out through a number of projects and represents a complex multiple project operation for investors, contractors, and other influential players. The national strategic developmental programme for the construction of the railway infrastructure is connected through programmes in neighbouring countries and EU member states to Trans-European Networks (TEN) that strategically regulate construction within the community. In the Republic of Slovenia, the construction of railway infrastructure within TEN programmes is carried out on the pan-European traffic corridors V and X within individual projects for the construction of sections and a number of supporting projects. Technical requirements, deadlines, and other TEN requirements as well as national strategic requirements and financial possibilities of the state represent basic criteria that should be taken into consideration in setting up a strategic project plan, with optimal project classification achieved through the implementation project portfolio. The current article utilised the method of multiple-criteria decision analysis to prepare the portfolio, taking into account macroeconomic and infrastructural criteria. Consequently, the results represent the basis for the preparation of an optimal financial plan with regard to financing possibilities of the Republic of Slovenia and the European Union. The article also summarised the research results regarding the formation of the project implementation process of the TEN-T network construction in the Republic of Slovenia.
Ključne besede: national strategic development, railway infrastructure construction, railway corridors V and X, project portfolio, multiple-criteria decision analysis, Republic of Slovenia
Objavljeno: 05.06.2017; Ogledov: 773; Prenosov: 325
.pdf Celotno besedilo (322,18 KB)
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Educationa Park - Technical Academy Maribor
Samanta Rebernak, 2016, magistrsko delo

Opis: The Educational Park - Technical Academy Maribor is a new concept with which we wish to enrich the city of Maribor. The main idea is to connect research and education with practical experience, start up companies and the production spaces of big companies. This broad content with multiple additions could be placed in the Business Industrial Zone Tezno, with certain modifications to the existing structures. This thesis deals with the evolution of industrial architecture and especially its importance to the city of Maribor. We present an in depth historical analysis of the company TAM, the predecessor of today’s BIZ Tezno, which was one of the biggest factories with research facilities and educational spaces in the former Yugoslavia. The urban master plan consists of the placement of the afore-mentioned content in the facilities of BIZ Tezno. The idea is to create an open, inviting space that would be a part of city life, with the addition of sports facilities, pool areas, a museum of industrial heritage, a concert hall, etc. As a continuation of the master plan, we also designed an industrial architectural model that shows how the concept of the Educational park can be implemented in the facilities of an established company. We also contemplated the use of renewable materials and, therefore, used timber in the construction. The facility would be an addition to the brand image of any company that values sustainable development and progress.
Ključne besede: degraded urban areas, brownfield, converting a factory complex, Maribor industrial heritage, TAM, industrial architecture, Science park, Technology Park, Industrial Park, Timber construction, Timber hybrid construction
Objavljeno: 20.04.2016; Ogledov: 1329; Prenosov: 125
.pdf Celotno besedilo (98,26 MB)

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