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This paper aims to present historical, aesthetical, conceptualand ideological similarities between the Haussmannian reconstructionof Paris that took place between 1852 and 1870 and the neoclassical reconstructionof Skopje named “the Skopje 2014 project”. The similaritiesbetween these two reconstructive projects will be inspected, as wellas (some important) differences. The main line of comparison is thenotion of the nation that is being constructed; alongside it, the notion ofidentity, invention and (re)construction of the past (an important aspectof the creation of the collective vision, necessary in most, if not all nationalisticprojects). This notion is rooted in the past (always gloriousand idealistic), and it is aesthetically anachronistic and ideologicallywell contextualized. The creation of these urban plans will thereforeserve as a corpus for an analysis of the creation of the national mythand the creation of the nationalistic narrative through architecture andurban planning.
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The paper analyzes and compares the energy demand for heating purpose of new buildings with different energy perfomance rates. Article studies global renewable energy sources innovations, statistics and scientific and engineering experience to ensure the building’s thermal energy needs, produced by transforming wind energy.Distribution of the potential of one renewable source – wind energy – during the year is similar to the energy necessary for the building heating, thus production of the heating energy from mechanic energy of the wind is chosen for further scientific investigations. Wind power plant, generating 2 kW of heat power, installed as a heating source for the analysed individual house, can cover from 40 to 76% annual heat needs of the building, subject to its energy-efficiency class, respectively 1.5 kW – from 31 to 68%, 1 kW – from 22 to 53%.
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The focus of newly published book “BIM Design. Realising the Creative Potential of Building Information Modelling” is building information modeling (BIM) - the dynamically arising topic of nowadays. The popularity and importance of the abbreviation BIM is becoming no less significant than that of the acronym CAD at the junction of the last two decades of the previous century.
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Use of natural pozzolan is growing rapidly in the construction industry due to its economical, ecological and technical benefits. However, they are often associated with shortcomings such as the need to moist-curing for longer time and a reduction of strength at early ages. Syria is relatively rich in volcanic scoria. The objective of the study is to investigate the effect of Blain fineness of cement on the strength development of scoria-based cement mortars. In the study, mortar specimens have been produced with four types of cement: one plain Portland cement (control) and three scoria-based blended cements with three replacement levels: 25, 30% and 35%, respectively. All blended cement types have been interground into four different Blaine fineness: 2400, 3200, 4200 and 5100 cm2/g. The development of the compressive and flexural tensile strength of all mortar specimens with curing time has been investigated. The effects of the Blaine fineness of the scoria-based blended cement on the compressive and flexural strengths of mortar have been evaluated at curing ages of 2, 7, 28 and 90 days, respectively. Test results revealed that there is a decrease in strength with increasing amounts of scoria. In addition, there was found an increase in strength with increasing the Blaine fineness values. Good correlations between mechanical strengths and Blaine fineness have also been observed at different curing times. Further, based on the results obtained, an empirical equation was derived to predict the mechanical strengths of scoria-based cement mortars with curing times based on Blaine fineness. Effects of Blaine fineness on some physical properties of blended cements have been reported, as well.
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Neris is the second longest river in Lithuania, flowing over the territory of Vilnius, the capital of Lithuania. It played an important role in the history of Vilnius, particularly, as a waterway, which, in the past, connected the Grand Duchy of Lithuania (GDL) with the neighbouring regions and countries. The river and its tributary, Vilnia, played the main role in the economic development of the city, as well as the development of the industry based on water-driven mechanisms, fishing and other riverside trades, recreational activities of the inhabitants and the urban infrastructure of Vilnius. The role of the river, which decreased in the second half of the 19th century because of the development of land (railway and automobile) transport, became negligible in the years of the soviet power (1945-1990). It happened due to the drop of water elevation caused by the intense drainage of the areas and, particularly, the barbarous construction of a dam at the riverhead in Belarus in 1974, which fenced off a large area of the Vileyka Reservoir. Moreover, the works for deepening the riverbed by removing stones and shoals were stopped, and it made the river unnavigable. The paper also describes frequent floods caused by the drifting of ice in the spring, which brought great damage to the city in the past, as well as the types of ships and rafts used for navigation.
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Additive of glass powder was successfully utilized in ultra-high performance concrete (UHPC) mixture.During experiment was found, that glass powder can be used instead of silica fume (SF), without decrease of mechanical properties and microstructure can be significantly increased. In experiment 100 % of quartz powder was substituted by glass powder. Quantitative and qualitative XRD analysis revealed,that glass powder improves hydration of Portland cement and in such way additional compressive strength up to 40 MPa can be gained. Designed mixtures were blended with laboratory mixer Eirich R02T and later with industrial mixer HPGM 1125. In new UHPC mixture was incorporated different amount of steel fibres. Flexural strength was increased about 5 times from 6.7 MPa to 36.2 MPa.
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By producing 1 ton of Portland cement clinker in environment releasing about 0.85 tons of CO2: 70% of limestone decarbonation and 30% of electricity and thermal consumption. High specific CO2 emissions results take the responsibility of Portland cement industry for about 5% of global CO2 emissions. One of the ways to reduce CO2 emissions is the use of Portland cement substituting materials. Properly treated ashes could become not a waste of biofuel but a valuable raw material for new construction materials. This paper presents results about the characterization of the biomass bottom ash sourced from the combustion of plant biomass located in Lithuania, and the study of new cement formulations incorporated with the biomass bottom ash. The study includes a comparative analysis of the phase formation and the setting of cement with bottom ash composite. Techniques such as X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), measurement of hydration temperature were used to determine the structure and composition of the formulations
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The magnetocaloric effect (MCE) is the thermal response of a magnetic material to an applied magnetic field. Magnetic cooling is a promising alternative to conventional vapor compression technology in near room temperature applications and has experienced significant developments over the last five years. Although further improvements are necessary before the technology can be commercialized.Researchers were mainly focused on the development of materials and optimization of a flow system in order to increase the efficiency of magnetic heat pumps. The project, presented in this paper, is devoted to the improvement of heat pump and cooling technologies through simple tests of prospective regenerator designs. A brief literature review and expected results are presented in the paper. It is mainly focused on MCE technologies and provides a brief introduction to the magnetic cooling as an alternative for conventional vapor compression technology.
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This article presents the results in the research of the load-carrying ability of reinforced-concrete nonpressure pipes with inner lining intended to protect concrete against corrosion. The lining (covers) are mounted as a stay-in-place formwork when manufacturing the pipes. The covers are made of 3-5 mm thick polyethylene sheets. To be fixed in the pipe wall concrete, the linings are provided with special anchoring elements. Two lining types are considered: 1 – with anchoring elements in the form of solid longitudinal ribs; 2 – with anchoring elements distributed equidistantly over the shell surface (≈400 pcs/m2).The research has been performed by numerical simulation using a three-dimentional finite element model. The load was applied according to a three-linear pattern used to test pipes for strength (including that specified in ЕN 1916). The computation was performed by the iteration method taking into account physical non-linearity of concrete. The computation makes allowance for formation and opening of cracks in the longitudinal pipe wall sections. The examples of computation of a pipe with the diameter of 2,000 mm and wall thickness of 150 mm reinforced with two cylindrical cages and a pipe with the diameter of 1,000 mm and wall thickness of 110 mm reinforced with a single cylindrical cage are given.It has been determined that the load-carrying ability of pipes with type 1 protective linings is lower than that of pipes with type 2 linings. Maximum (up to 25%) reduction of the load-carrying ability is observed in pipes reinforced with a single cylindrical cage. In pipes of this type, cracks are formed at lower loads.The load-carrying ability of pipes is reduced due to entering of anchoring ribs of the protective shell into the compression zone of the pipe wall concrete in the sections located at the level of the horizontal diameter. The results of the numerical computation are in good agreement with those obtained when testing full-scale specimens of pipes with specified technical parameters.To protect interior faces of reinforced-concrete non-pressure pipes, it is recommended to use lining covers with V-type discrete anchoring members ensuring reliable mechanical fixing of the linings in the pipe wall concrete. This type of anchoring elements causes almost no effect upon the load-carrying ability of pipes.
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In this article the influence of the panel slab, girder slab formwork and tableforms to the effectiveness of solid concrete slab construction works of multi-storey buildings is investigated. The object of investigation is 22-storey high-rise commercial residential building. The effectiveness of solid concrete slab construction works and selecting the formwork system was evaluated taking account of quality requirements, equipment ability, demand of time and labour i.e. complexity of assembling technology, universality of operation and other. Three options of PERI formwork systems were selected for investigation: SKYDECK panel slab aluminum formworks, MULTIFLEX girder slab formworks and UNIPORTAL tableforms. The rating criteria were selected for the evaluation of the effectiveness of selected formwork systems. Using the pairwise evaluation method the following order of criteria importance was obtained: 17.3% – formwork rental price (K7), 16.3% – complexity of assembling technology (K3), 15.4% – machinery costs (K2), 13.9% – labour costs (K1), 13.0% – required compressive strength of concrete before formwork demoulding (K5), 12.5% – formworks demoulding time, days (K6), 11.5% – reliability of suppliers (K4). The evaluation of formwork systems, as options, according to selected evaluation criteria, was performed by TOPSIS method and the results show that for the mounting of concrete slabs in the investigated building the rational option is to use SKYDECK panel slab aluminum formworks.
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From 2016 “A” energy efficiency class buildings should be designed and built in Lithuania, as their energy consumptions are considerably less comparing with the ones that were built before. In order to meet high requirements of “A” energy efficiency class buildings should be used new energy efficient structural and insulating solutions should be made. In order to evaluate overall heat losses in these joints more exactly it is required to calculate values of heat transmission coefficients of linear thermal bridges in “A” energy class buildings.The project of semi-detached building was chosen in order to analyse influence of linear thermal bridges for building’s energy consumption as there are all kinds of linear thermal bridges which values must be calculated. Buildings energy efficiency designing program, which based on EN ISO 13790, was used to calculate building’s heat losses. Heat transmission coefficients of linear thermal bridges were calculated using program THERM. Two variations were analysed: building’s energy consumptions are close to the lowest point of A class requirements when building’s envelopes and joints of units in joint places are the same as they are in currently built houses; and effective energy solutions of building’s joints.The results of analysis showed that requirements of “A” class can be reached using ordinary solutions for building’s envelopes and joint units but if linear thermal bridges are designed like that, it makes 16 % heat losses through envelopes, and it is similar to heat losses through building’s walls (17 %), furthermore, it is about 1.5 times bigger than heat losses through roof (10 %) or floors (10 %). Specific heat losses of thermal bridges make 7.80 kWh/m² per year. The biggest overall heat losses are through walls and windows joint thermal bridges (specific heat losses make 13.55W/K). Another significant part of heat losses comes from walls and floor joints (specific heat losses make 11.88W/K).After solutions of buildings with energy effective building’s envelopes and units joints were analysed it can be stated that overall heat losses decreased about 10 kWh/m² per year, it is 20 %. Heat losses through thermal bridges make only 3 % of overall heat losses through envelopes, it is 122 kWh/m² per year.According to results of the analyse general specifications were made for designing building envelopes of “A” energy efficient class:- The building of “A” class can be designed using ordinary solutions of linear thermal bridges, bigger heat losses through thermal bridges can be covered by increasing thickness of thermal insulating layers and using windows of better thermal behaviour but as a result the costs of building house increase too.- When effective solutions of linear thermal bridges are used, the same energy efficiency of the building can be reached using less thermal insulating layers, windows and doors of less thermal behaviour if the building of better energy characteristics is designed.
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The fracture mechanics parameters are used in different applications to formulae the classic criteria of failure as well as in computational models to analyze the concrete structures and other brittle materials. The parameters are determined using the specimens with notches. The study for assessing the influence of the notch curvature in specimen on fracture mechanics parameters, e.g. critical stress intensity factor, critical crack tip opening displacement and fracture energy, was performed on cement mortar as a typical quasi-brittle material. The U-shaped notches with a depth of 30 mm were formed during molding the specimens. The radius of notch curvature was changed in the range from 0.15 mm to 30.0 mm. The results obtained demonstrated that the notch curvature radius has a significant effect on the level of maximum stress and the parameters describing the cement composite resistance to cracking. Therefore, the experimental determination of the fracture characteristics requires a strict definition of the test conditions.
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High-voltage poles made in 1956 had to satisfy the cross-sectional geometry related standard (GOST 8509-57 confirmed later). However, the stricter requirements weren’t applied for the microstructure. In this paper a strength analysis of the pillars’ material is provided. The technological specificities of profile manufacturing were mostly determined by differences in mechanical properties influenced by differences in microstructures of pillars’ material investigated. Although the confirmed standard of steel CT3 (GOST 380-71) had new requirements and clear criteria of microstructure acceptance but made pillars with the non-homogeneous microstructure remained standing. The differences in microstructural components create conditions for appreciable differences in mechanical properties such like yield stress and ultimate stress, fracture strain. In this paper, the limits of elastic and plastic strains are identified in order to quantify the changes in elastic and plastic properties with the differences in their intensity for selected step-like stress range. Corrosion depth and width play the large role and ones often determine the fracture location of samples. The end of this work is dedicated to conclusion based on the relation of experimental part and analytical calculations presented.
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The present study is part of a wider research program, which aims at the development of an innovative masonry construction system that integrates both environmental passive strategies and high energy efficiency. The paper focuses on the parametric computational investigation of the proposed system’s basic modular construction component. The thermal performance achieved by alternative geometries of the masonry unit, as well as the use of different constituent materials and insulation fillings, are further examined. The optimum solutions, in terms of thermal performance, were achieved by performing a series of numerical heat flux analyses on alternative proposals, arising from the combination of the above features. Furthermore, the environmental impact, associated with the construction system, is assessed by estimating the total embodied energy of the modular component. It is concluded that the proposed system’s thermal performance relies primarily on the characteristics of the constituent mixture composing the modular masonry unit, the geometry of the unit and the use of insulation. In terms of environmental impact, both the constituent mixture used, and the type of insulation material installed, have a considerable impact on the end-product’s total embodied energy.
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Buildings have a considerable environmental impact that corresponds to almost 30% of the global carbon footprint, with a prediction for further growth, and to 40% of the final energy consumption in the EU. The EU therefore has set a goal to reduce primary energy use by 20% by 2020, which is one of the five headline targets of the European 2020 Strategy. Moreover, the European Commission has established since 2002 a common policy for sustainable buildings and low environmental impact materials promoting energy efficiency and reduction of greenhouse gases (GHGs), based on a series of directives and regulations. A key role parameter for sustainable building construction is the appropriate building envelope’s thermal insulation in order to reduce its thermal losses. This was firstly introduced in Greece with the Regulation of Building Insulation in 1979. Therefore, the paper focuses on the implementation of thermal insulation at buildings in compliance with the Greek national legislation framework during the last forty years. In this line of approach, measurements of the U-values and of the internal and external surface temperatures were carried out, in residential and office buildings. The sample consisted of buildings with construction dates that mirrored the development in legislation and in the building practice.
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Even if the EU has made important progress towards meeting its climate and energy targets for 2020, the effects of financial instability due to the economic crisis are still apparent, especially in the southern European countries, acting as a great obstacle for residents to invest in energy retrofit projects in order to improve their house energy performance. EU Member States striving to limit the risks that such investments entail and to aid with high upfront costs are using financial incentives in the form of funding schemes, grants, tax exemptions/reductions etc. as a way of spurring investments in energy efficient services and technologies. Within this framework, the current study deals with the financial attractiveness of investments in the presence and absence of incentive schemes for energy retrofitting of residential buildings in three European countries (Cyprus, Greece and UK). The methodology followed uses, as a first step, three case studies of typical residential buildings, one for each country, for the computation of pre-retrofitting and post-retrofitting energy demands. Material and labor costs that apply in each country together with energy costs and economic parameters are taken into account in order to sum up the initial energy upgrade budget for each case. The second step regards the computation of investment criteria such as NPV and IRR and the analysis is performed for a 30-year period to account for the life-cycle of a building using economic parameters such as Discounting and Inflation Rates. Then, the particulars of each Country’s funding scheme are incorporated into the economic model to reveal their benefits and evaluate their attractiveness. The final output of the study comprises a comparative analysis of the current funding schemes using Present Worth as an indicator for the evaluation of their application in each country. Followed the analysis conducted it is concluded that the Cypriot and Greek funding schemes have a strong effect when applied and evaluated in all three countries. On the contrary, the UK’s funding scheme is not applicable in terms of financial attractiveness in the case of Greece and Cyprus.
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The construction industry, contributing to about 9% of the European Union’s GDP, has played a significant influential role in the development of the energy strategy of Europe and is also anticipated to be an important contributor in its successful implementation (EC, 2016). Holistic sustainability assessment tools that are able to evaluate and optimise the environmental performance of construction materials and buildings are considered a key for the development of advanced building designs and use of sustainable building materials and elements and green energy- efficient systems that will raise high the sustainability level of the European built environment. The aim of this work is the thorough explanation of the standardised LCA methodology, and the introduction of the approach of EcoHestia, a comprehensive building sustainability assessment tool. In view of that, the current legislation addressing the construction industry, as well as the state-of-the- art Life Cycle Assessment (LCA) tools that are used for the sustainability assessment and optimisation of construction materials and buildings are also presented. Furthermore, through the employment of EcoHestia, the environmental impact of a case study building is defined, also providing a detailed breakdown of the contribution of each construction material in the overall environmental performance of the building. The analysis of the results has not only determined on the construction materials of the building that are most harmful to the natural resources and the environment, but also showcased the effectiveness and added value of utilizing this approach in moving forward towards a more sustainable green building sector.
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The fragility curves are an essential tool in the seismic assessment of structures and provide a versatile tool to conduct vulnerability analysis for retrofitting and strengthening purposes. The available advancements of computer computational power led to the improvement of the efficiency of the analytical fragility curves. Therefore, this paper focuses on reviewing the recent research developments in the analytical fragility analysis methods. Furthermore, the developments of the intensity and damage measures are presented. In addition, the joint hazards effects on structural fragility are addressed particularly for the environmental degradation and mainshock-aftershock sequence. Finally, recommendations are presented for improving the fragility analysis and highlighting the possible future research areas.
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The rheological and mechanical performance of cement paste is closely related to its packing density, which may be optimized by improving the particle size distribution in the paste mix. In this study, the authors propose modifications to the existing mathematical equations of particle size distribution. The new equation of optimal particle size distribution so formulated is verified experimentally. A series of cement paste having different water/cementitious materials (W/CM) ratios were produced by blending ordinary Portland cement (OPC) with varying contents of superfine cement (SFC). The particle size distributions of the blended paste mixes were compared with the proposed equation. The packing density of paste mixes was measured using the wet packing test method, and the flowability, rheological properties, and compressive strength of the paste mixes were tested. It is found, that the particle size distribution in cement paste can be improved by blending with SFC, which can lead to enhancement in packing density, flowability, rheology and strength. The authors opine that the proposed equation of particle size distribution may be applied for mix design optimization of cementitious paste, including cementitious grout and the paste phase in mortar and concrete.
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