Risk of hydraulic structures from the point of view of the so called “black swans”

Diplomová práce je zaměřena na problematiku černých labutí v oblasti vodohospodářských staveb. Detailněji potom na rizika a ohrožení vodních děl. Historie nám ukázala, že ani tak sofistikovaná stavba jako přehrada nemusí být vždy bezvadná. Ať už se jedná o přírodní katastrofu, neštěstí, či úmyslný útok. V práci je provedena analýza současného stavu, zmapovány černé labutě u přehrad, které se staly v historii. Součástí práce je i průzkum znalosti obyvatel o této problematice. Na základě analýzy a zjištěných informací byla navržena opatření pro zlepšení situace.The thesis is focused on the issue of black swans in the water structure. More detail risks and hazard dam. History has shown us that sophisticatedly structure as dam is not perfect. Failure can cause weather, natural disaster, bad chance or deliberate attack. A detailed analysis of the current situation, I mapped historic dam failure, which can cause black swan. In thesis is a reseach on knowledge of the population in this issue. Based on the analysis and obteined information was proposed measures to improve the situation.

Indoor pool ventilation

Tato bakalářská práce je zaměřena na návrh vzduchotechnického zařízení bazénové haly. Hala je rozdělena na čtyři samostatné celky. První zařízení je navrženo jako klimatizační jednotka pro šatny. Pro plavecký bazén byly navrženy bazénové klimatizační jednotky s tepelným čerpadlem. Vzduch v tobogánové hale je upravován pomocí jednotky nuceného větrání.The bachelor thesis designed ventilation for the pool hall. Hall is divided on four separate working units. The first device is designed as an air-conditioning unit for the changing room. For swimming pool were designed swimming pool air conditioning units with heat pump. Air in the hall with a water slide is adjusted using the forced ventilation unit.

Heat recovery in Building Services

Diplomová práce se zabývá optimalizací stokového výměníku pro zpětné získávání tepla. Pro správný návrh a optimalizaci je potřeba použít tři základní metody: diagnostiku, tepelně bilanční výpočty a modelování. Ve 2D softwaru Calculation Area jsou nasimulovány různé typy stokových výměníků umístěných v kanalizačním potrubí. Pomocí modelů ze softwaru CalA a následných simulací bude vybrána optimální varianta stokového výměníku. Pomocí softwaru BSim, který je založený na více zónové numerické simulaci energetických potřeb budov ve vazbě na vnitřní klima, jsou zjištěny potřeby tepla administrativní budovy. Optimální počet stokových výměníků je navržen ze zjištěným výkonů tepelných výměníků a potřeby tepla pro budovu.This thesis deals with the optimization of sewer heat recovery. For proper design and optimization it is necessary to use three basic methods: diagnostics, heat balance calculations and modeling. In 2D software Area Calculation are simulated different types of sewer exchangers arranged in sewer pipes. Using models of software CalA and simulations will be selected optimal variant. Using software BSim, which is based on more zone numerical simulation of the energy needs of buildings in relation to indoor climate, are detected heat needs of an office building. The optimal number of sewer exchanger is designed from the identified performance heat exchangers and supplies heat for the building.

Statistical and practical evaluation of the mechanical and fracture properties of steel fibre reinforced concrete

The sustainability of the construction industry requires new perspectives on existing techniques. For example, fibre concrete has been an integral part of the construction industry for many years and its contribution to enhancing the properties and use of concrete is undeniable, but there are still some questions that need to be answered. The present paper showed the possibilities of statistical evaluation of crack mouth displacement (CMOD) tests performed on 24 fibre concrete specimens. The aim was to point out possible pitfalls and to propose measures based on statistics. The geometrical properties of all samples were determined and correlated with the results of the CMOD test. In this paper, a procedure was considered to compare two different concretes with different fibres at CMOD level. Correlations between geometry and CMOD test results were also demonstrated.Web of Science128art. no. 108

Concrete: Limit States and Sustainability

The structural design of concrete structures has to result in qualities ensuring ordinary structural safety and serviceability, together with durability. Recently, it has become necessary to pursue sustainability as well, and rather newly the issue of resilience has also appeared. It is now apparent that the effects of mechanical load, environmental load and even social coherence need to be reflected and included in the formulation of limit states. This is a complex matter involving the factors of time, service life, degradation effects, modelling, probability analyses, limit states, costs and other phenomena. It has not yet been completely understood, albeit several notions in this context are contained in different codes and regulations, e.g. EN 1990, EN 1992, ISO 13823:2008, ISO 16204:2012, fib MC2010 and fib MC2020 (currently under preparation by the fib committees). According to fib Model Code 2010, the design method most commonly used for concrete structures today is performance-based. Sustainable target value design can be briefly expressed as the comparison of sustainable capacity vs. sustainable impacts. This requires the formulation of a new class of limit states – apart from those of the engineering (or structural) type, also sustainability limit states now need to be specified. The presented contribution briefly mentions traditional and durability limit states, discussing their variants and context, and then concentrates specifically on the formulation of limit states for concrete sustainability at material level. It also presents some examples which apply a full probabilistic approach

Sensitivity analysis of stochastic calculation of SCC regarding aggressive environment

Probabilistic procedures considering the durability with respect to corrosion of reinforcement caused by aggressive substances are widely applied; however, they are based on narrow assumptions. The aspects need to be evaluated both in terms of the search for suitable application of the various experimental results and in terms of their impact on the result of the stochastic assessment itself. In this article, sensitivity analysis was used as an ideal tool to prove how input parameters affect the results of the evaluation, with consideration of different types of concrete (ordinary or self-compacting with and without fibres). These concretes may be used in aggressive environments, as an industrial floor or as a part of the load-bearing bridge structure. An example of a reinforced concrete bridge deck was selected as the solved structure. The results show that in the case of a classic evaluation, a larger amount of fibre reports a lower resistance of concrete, which contradicts the assumptions. The sensitivity analysis then shows that self-compacting concrete is more sensitive to the values of the diffusion coefficient, and with the consideration of fibres, the effect is even greater

Sustainability levels in comparison with mechanical properties and durability of pumice high-performance concrete

In the production of cement and concrete, mechanical and durable properties are essential, along with reasonable cost and sustainability. This study aimed to apply an evaluation procedure of the level of sustainability of mixtures of high-performance concretes (HPC) with various eco-friendly supplementary cementitious materials (SCM). The major supplementary cementitious materials (SCMs), namely, volcanic pumice pozzolan (VPP), Class C and F fly ash, ground granulated blast furnace slag of grade 120, silica fume, and metakaolin, were included. Twenty-seven concrete mixtures were analyzed using a previously presented comprehensive material sustainability indicator in a cost-effective variant. The results indicated that the rank of the concretes differed at 28, 56, and 91 days after concreting. In addition, the study showed no correlation of strength and diffusion parameters with sustainability indicators. Finally, this study will contribute to the optimal selection of mixtures of HPC with VPP in terms of sustainability, cost, and durability for future implementation in reinforced concrete bridge deck slabs and pavements. The values of sustainability indicators for pumice-based mixtures were compared with those for other SCMs, highlighting the sustainable performance of volcanic ash-based SCM.Web of Science1111art. no. 496

New opportunities for the use of concrete structures sustainability assessment tools for a forensic engineering

In recent years, the European Union has been working to revise its climate, energy, and transport legislation to align existing legislation with the goals set for 2030 and 2050. These ambitions are closely related to the principles of sustainability. A growing population places increasing demands on the environment. Thus, improving living standards without damaging the environment is becoming a global challenge. The construction industry is an important segment of the world economy and contributes to environmental pollution. The concrete industry can also be counted among the main producers of CO2 emissions. The future of concrete construction design will be linked to new but also ongoing transformations of our society. The rapidity, speed, and frequency of the changes that are being implemented will also create a new urgency for knowledge and methodology in this field, whether for concrete producers, designers, or forensic experts. The focus of this thesis is the need to respond to new requirements in the field of concrete structures. In June 2016, the fib board approved activities to start working on the development of an updated fib Model Code 2020 (MC2020). This Model Code 2020 will form the source of new versions of the relevant Eurocodes and ISO standards, with sustainability as a fundamental requirement. Therefore, the design of a structure will now have to take into account not only durability considerations but also performance and overall environmental impact. Therefore, the dissertation focuses on the analysis of new trends in concrete structures to categorize the areas of change that may occur. The thesis deepens understanding of the areas of change as well as the methods of evaluation of building materials and concrete structures. Based on the identified shortcomings of the methods to assess the sustainability of materials, a sustainability indicator for CSB has been proposed. The changes brought about by the new fib Model Code 2020, whether in terms of performance-based design, use of recycled materials, or optimization of structures, may lead to defects and failures in building structures and new types of legal dispute for which there are no algorithms for resolution. In this paper, modern devices used for defectoscopy of defects and failure of concrete structures are also described

New opportunities for the use of concrete structures sustainability assessment tools for a forensic engineering

V posledních letech Evropská unie pracuje na revizi své legislativy v oblasti klimatu, energetiky a dopravy s cílem sladit stávající právní předpisy s ambicemi stanovenými pro roky 2030 a 2050. Tyto ambice úzce souvisí s principy trvalé udržitelnosti. Stoupající počet obyvatel klade čím dál vyšší nároky na životní prostředí. Zlepšení životní úrovně bez poškození životního prostředí se tak stává globálním problémem. Stavebnictví je důležitým a segmentem světové ekonomiky a zároveň přispívá ke znečišťování životného prostředí. Mezi významné producenty emisí CO2 můžeme zařadit také betonářský průmysl. Budoucnost navrhování betonových konstrukcí bude spojená s novými, ale i pokračujícími přeměnami naší společnosti. Razantnost, rychlost a četnost prováděných změn vyvolá i novou naléhavou potřebu poznatků a metodických postupů v této oblasti, ať už půjde o výrobce betonu, projektanty tak i soudní znalce. Zaměření práce vyplývá z potřeby reagovat na nové požadavky v oblasti betonových konstrukcí. V červnu roku 2016 schválila rada fib aktivity v rámci zahájení prací na tvorbě aktualizovaného fib Model Code 2020 (MC2020). Tento Model Code 2020 bude tvořit zdroj nových verzí příslušných eurokódů a ISO norem, přičemž udržitelnost bude považována za základní požadavek. Při návrhu konstrukce tak bude nově nutno zohledňovat nejen hledisko životnosti, ale též výkonnosti a celkového dopadu na životní prostředí. Disertační práce se tak zaměřuje na analýzu nových trendů betonových konstrukcí s cílem kategorizovat oblasti změn, které mohou nastat. Práce prohlubuje poznání o oblastech změn i metodách hodnocení stavebních materiálů a betonových konstrukcí. Na základě zjištěných nedostatků metod k hodnocení trvalé udržitelnosti materiálů byl navržen indikátor trvalé udržitelnosti kSB. Změny, které přinese nový fib Model Code 2020, ať už jde o navrhování staveb na základě principu performance based design, využívání recyklovaných materiálů, či optimalizace konstrukcí, může vést ke vzniku vad a poruch stavebních konstrukcí a nových typů právních sporů, pro něž neexistují algoritmy řešení. V práci jsou popsány také moderní přístroje sloužící k defektoskopii poruch vad a poruch betonových konstrukcí.In recent years, the European Union has been working to revise its climate, energy, and transport legislation to align existing legislation with the goals set for 2030 and 2050. These ambitions are closely related to the principles of sustainability. A growing population places increasing demands on the environment. Thus, improving living standards without damaging the environment is becoming a global challenge. The construction industry is an important segment of the world economy and contributes to environmental pollution. The concrete industry can also be counted among the main producers of CO2 emissions. The future of concrete construction design will be linked to new but also ongoing transformations of our society. The rapidity, speed, and frequency of the changes that are being implemented will also create a new urgency for knowledge and methodology in this field, whether for concrete producers, designers, or forensic experts. The focus of this thesis is the need to respond to new requirements in the field of concrete structures. In June 2016, the fib board approved activities to start working on the development of an updated fib Model Code 2020 (MC2020). This Model Code 2020 will form the source of new versions of the relevant Eurocodes and ISO standards, with sustainability as a fundamental requirement. Therefore, the design of a structure will now have to take into account not only durability considerations but also performance and overall environmental impact. Therefore, the dissertation focuses on the analysis of new trends in concrete structures to categorize the areas of change that may occur. The thesis deepens understanding of the areas of change as well as the methods of evaluation of building materials and concrete structures. Based on the identified shortcomings of the methods to assess the sustainability of materials, a sustainability indicator for CSB has been proposed. The changes brought about by the new fib Model Code 2020, whether in terms of performance-based design, use of recycled materials, or optimization of structures, may lead to defects and failures in building structures and new types of legal dispute for which there are no algorithms for resolution. In this paper, modern devices used for defectoscopy of defects and failure of concrete structures are also described.