bluuebunny/crossref_metadata_2025 huggingface dataset:
Theoretical prediction of punching shear capacity of flat slabs without shear reinforcement strengthened by concrete topping
Authors: Čereš Daniel , Gajdošová Katarína
Published: December 2021

The main reasons for strengthening flat slabs are the change of the use of a building, increase in the value of loads, degradation of the concrete cover layer, or insufficient reinforcement. This paper is focused on the assessment of punching shear capacity of the strengthened flat slabs without shear reinforcement. One of the possibilities how to enhance punching shear capacity is the addition of reinforced concrete topping. The main goal of this paper is to compare the possibilities for calculation of the increase in the punching shear capacity by investigation of the influence of different thicknesses of concrete toppings and different reinforcement ratio. A reference specimen is represented by a fragment of a flat slab with the thickness of h = 200 mm supported by circular column with the diameter of 250 mm. Three different thicknesses (50 mm, 100 mm, 150 mm) of concrete toppings were considered together with three different reinforcement ratios for each thickness of concrete overlay. Theoretical predictions of the punching shear resistance of flat slabs were evaluated by design guidelines according to the relevant standards: Eurocode 2 (EN 1992-1-1), Model Code 2010 and draft of the second generation of Eurocode 2 (prEN 1992-1-1). The differences in the influence of reinforcement ratio are significant. In Model Code 2010 the reinforcement ratio in concrete topping was considered in equation of moment of resistance. This is unlike in both of the mentioned Eurocodes, where the reinforcement ratio was assumed as a geometric average value of the original reinforcement ratio in the slab before strengthening and of the reinforcement ratio of concrete topping. All the predicted theoretical calculations are based on the perfect connection and bond between the original and new layer of concrete. These predictions should be verified by experimental investigation, which is going to be prepared shortly. By the additional increase in the thickness of concrete topping or in the amount of added reinforcement the attention should be payed to the limitation of the punching shear resistance by the value of the maximum punching shear resistance in the compression concrete strut.
Artificial Neural Network Prediction of Airport Pavement Moduli Using Interpolated Surface Deflection Data
Authors: Baldo Nicola , Miani Matteo , Rondinella Fabio , Celauro Clara
Published: December 2021

Establishing the structural integrity of an airport pavement is crucial to assess its remaining life and implement strategies or priorities for action. In this context, the elastic modulus represents an effective indicator of the condition of the pavement which can be calculated through back-calculation procedures starting from surface deflections, obtained from a non-destructive test (such as the Heavy Weight Deflectometer). Nevertheless, the conventional inverse engineering analysis involves the use of an axial-symmetric pavement finite-element program able to evaluate stiffness values exclusively at the deflection measuring points. This study presents an alternative methodology for spatial modelling of the load- bearing capacity of the runway surface pavement layer from deflection data measured at specific points, using Shallow Artificial Neural Networks. The search of the optimal neural model hyperparameters has been addressed through a Bayesian Optimization procedure and a 5-fold cross-validation has been implemented for a fair performance evaluation, given the limited number of deflection measures available. Once the optimal model has been defined, the measured surface deflection data were linearly interpolated and resampled gridding data were used as a new input matrix of the neural model to predict the expected value of elastic moduli at non-sampled points on the runway. The optimal BO model has returned very satisfactory results with a value of Pearson Coefficient R averaged over 5-fold equal to 0.96597 and of Mean Squared Error averaged over 5-fold equal to 0.01849. In such a way, a contour map of the runway stiffness has been drawn, to provide a support tool for the planning of intervention priorities.
Comparison of the New Type Modular Panel for Green Roofs and Classical Construction of Green Roofs by Stormwater Management
Authors: Hejl Martin , Mohapl M. , Bříza Lukas
Published: December 2021

Proper stormwater management is one of the main problems cities today face. In order to understand how to properly manage urban stormwater it is first necessary to construct roofs with new construction methods. The first step for controlling urban stormwater is the construction of green roofs. We already know that the construction of green roofs improves water management in cities. But can we make it better? What will happen if we use the same layers for the green roofs but with a different construction method? This article wants to answer these questions. In this article the two green roofs, differing in the construction method, are compared and contrasted in terms of stormwater management. One of the green roofs was built traditionally, while the other has been built using a new type of modular panel. The article then compares their results during laboratory tests. In the conclusion you can read about measured data from tests and possible solutions and development of solutions to improve green roofs in the future.
Research on the Present Situation and Development Trend of Subway Tunnel Inspection Vehicle
Authors: Wang Kaitian , Li Panshan , Liu Yang , Li Hu , Men Yanqing , Huang Yongliang
Published: December 2021

For the operational subway tunnel, the manual inspection accounts for the majority in terms of detecting the diseases and damage of tunnel. The accuracy of manual inspection mainly depends on the professional level of the detection personnel, and the whole detection process always is inefficient, which cannot meet the needs of actual tunnels. To address this issue, the intelligent mobile tunnel detection vehicle emerges as the times require. By using advanced technologies such as laser scanning and high-speed camera array, the subway tunnel detection vehicle has achieved the advantages of simple operation, comprehensive function and automatic detection. However, the current subway tunnel detection vehicle mainly realizes the scanning detection of tunnel surface diseases, and the detection of tunnel structural diseases is less involved. Based on the track and tunnel detection requirements, this study analyzes the current situation and existing problems of subway tunnel detection comprehensively, puts forward the development direction of tunnel structure detection, and the application prospect of intelligent detection vehicle in subway tunnel is prospected.
Mechanical Behaviour of a Residual Soil from Ignimbrite Rock of São Miguel Island - Azores
Authors: Pais Luís Andrade , Maia Carvalho P. E. , Gomes Ferreira , Cavaleiro Victor , Malheiro Ana
Published: December 2021

Azores consists of nine islands and several islets, located in the North Atlantic to 1600 km from Continental Portugal and is distributed between latitudes 36° 55' to 39° 43' N and longitude 24° 46' to 31° 16' W. Azores archipelago is in a convergence zone of a series of dynamic tectonic structures, that are responsible for seismicity and volcanism, geological and petrological of these islands. The island of São Miguel, an eastern group, in addition to other petrology’s in its geology, has ignimbrite, which is a pyroclastic rock with a dacitic or rhyolitic composition, resulting from the deposition of materials in semi-melting at high temperatures from a pyroclastic flow. At the site of Água D’Alto, the residual soil sample resulting from the ignimbrite alteration was taken and was evaluated with the interest of studying its application or use as construction material. The soil was subjected to physical and chemical classification test, compressibility, and stress-strain behaviour. This material shows good mechanical characteristics, although its chemism is potentially corrosive.
Mobility in Transportation Surveys
Authors: Olenkowicz-Trempała Paulina , Sobota Aleksander , Chmielewski Jacek , Kempa Jan , Santos Bertha , Gonçalves Jorge
Published: December 2021

An attempt to identify key factors impacting trip generation in different size cities is presented in this paper. Mobility is the fundamental factor in transport demand models, both for the present state and those for forecast scenarios. Moreover, research on inhabitants' mobility plays an important role in the process of urban and rural traffic modelling. It comes from the fact, regular transport surveys make it easier to determine factors impacting the number of trips taken by inhabitants in any selected study area, and to determine trends in these factors. Presentation of example results of mobility rate based on transportation surveys taken in various areas of Poland is the main goal of this paper. Results of analyses of selected macro-economic factors in transportation systems shaping are presented either. The trends in the number of inhabitants and their age composition, and motorization rates are those factors. They impact mobility ratios in the study area. Values of mobility ratio were developed based on the results of surveys which have been done in Poland till now, and on the authors' research. Mathematical regression models in estimating mobility ratio versus the selected independent factors are the results of this research either.
The best housing estate in Czechoslovakia
Authors: Guzdek Adam
Published: December 2021

The Brno housing estate Lesna is undoubtedly an important achievement of Czechoslovak urbanism and architecture of the 1960s. It was built on the southern slopes north of Brno in 1962–1970 according to a project by a team of architects Frantisek Zounek, Viktor Rudis, Miroslav Dufek and Ladislav Volak. Although it was a standard housing construction made of prefabricated components, the architects did not want to hide its technical expression. They also fully copied it into the very urban arrangement of long blocks, which contributed to the fulfillment of the vision of the garden city. Close cooperation between the supplier, investor and designer was ensured already in the phase of elaboration of the project task. The architecture of residential buildings is based on the diligent efforts of the whole team to promote the use of a lightweight facade of a prefabricated house using parapet panels and strip glazing in the B 60 construction system. The unusually high-quality solution of the public space in the Lesna housing estate was mainly due to the time of its creation. Political liberalization in the 1960s allowed architects to come up with a generous plan for a free stop and thus perfectly fulfill the vision of a garden city. The population density of the Lesna housing estate, less than two hundred inhabitants per hectare, was multiplied by up to four hundred inhabitants per hectare in other housing estates of the "president Gustav Husak" era due to tightening economic indicators. Public greenery respecting the natural elements of the rugged relief required a different professional approach due to the extent of the exterior design. It was common practice that landscaping were carried out on residential complexes with a delay of several months and years after the first inhabitants moved in. The architects managed to reverse this common practice, so the first inhabitants moved to finished houses with access sidewalks, planted greenery and functioning residential amenities. This could not have been imagined by its inhabitants in the later realizations of housing estates. That is why the Brno housing estate Lesna is rightly called the best.
Application of Fluidized Bed Furnance Bottom Ash in Civil Engineering – A Review
Authors: Kaczmarczyk Grzegorz
Published: December 2021

For several years there has been widespread and open discussion about climate problems and human responsibility for the generated waste. The number of regulations has led to a search for applications for by-products of combustion. Moreover, the forecasted economic crisis additionally motivates to use every possible material to reduce the cost of manufacturing activities. Efficient waste management is a key element for Polish companies in their efforts to reduce their negative impact on the environment. Fluid combustion of fuels in the Polish power and heat industry still belongs to relatively new technologies. Despite the application of the most technologically advanced processing methods, bottom ashes from fluidized bed boilers are still reluctantly used. The author sees possibilities of using bottom ashes in geotechnical works. The aim of this review is to present the existing source papers relating to the use of bottom ashes in construction processes. A particular area of interest is the use of said ashes in jet-grouting (JG). The paper briefly refers to fluidized bed combustion technology as a source of combustion byproducts. The author pay special attention to the characteristics defining the characteristics of the ashes. The reader's attention will then be drawn to jet-grouting technology. References can be found to the methodology of general cement-soil testing. Due to the nature of the use of JG, the focus is particularly on their strength, water-permeability and frost resistance properties. Due to the need to determine the internal structure of the cement-ground, attention was also paid to the possibility of using X-ray computed tomography for soil cement testing.
Green Areas in the City as an Element of Noise Protection
Authors: Kowalska-Koczwara Alicja , Pachla Filip , Tatara Tadeusz , Nering Krzysztof
Published: December 2021

From the dawn of history, humanity created communication routes in order to move efficiently. Trees were planted along the roads connecting towns and villages so that travellers could rest in their shade. The line of trees also played an informative, strategic and sometimes aesthetic role. Currently, a line of tall vegetation along the street provides shade and relief in cities during hot weather. It is also worth emphasizing that greenery reduces stress factors in large cities. One of the stressors in cities is noise. In an urbanized environment, noise is perceived as unpleasant and bothersome. Appropriate planting of greenery in the city can reduce this phenomenon. The article not only analyses the possibilities of reducing noise through appropriate planting of greenery, but also provides guidelines for the correct design of greenery along streets and at crossroads. It is worth emphasizing here that the correct design of greenery in the vicinity of communication arteries is not only a matter of ethics or landscape legibility, but also a matter of safe use of infrastructure. The article also deals with the issue of legal acts relating to the design of urban greenery. The former and current legal acts contain provisions related to the classification of green areas, their protection and shaping. These regulations apply to various fields (construction, spatial planning, environmental protection) and therefore there are discrepancies in the legal interpretation of this term. All these doubts will be clarified.
International Roughness Index Modeling For Jointed Plain Concrete Pavement Using Artificial Neural Network
Authors: Sultana Salma , Yasarer Hakan , Uddin Waheed , Barros Rulian
Published: December 2021

Climate attributes such as precipitation, extreme temperature, and freeze-thaw cycles along with traffic loads cause pavement distresses. The maintenance need for pavements is decided based on the pavement condition rating such as International Roughness Index (IRI). Generally, an IRI rating less than 2.68 m/km is acceptable, and a rating greater than 2.68 m/km is considered unacceptable and classified as “very poor” condition of the pavement. It is imperative to be able to accurately predict pavement conditions to prepare proper Maintenance and Rehabilitation (M&R) programs for the pavements. This study aims to develop IRI models that can successfully estimate the IRI values for Jointed Plain Concrete Pavement (JPCP) considering the M&R history of the pavements using Artificial Neural Networks (ANNs) approach. The study was carried out with the database collected from Long Term Pavement Performance (LTPP) program. The variables used for the ANN model development are initial IRI, pavement age, concrete pavement thickness, equivalent single axle load (ESAL), climatic region (wet-freeze, wet non-freeze, dry-freeze, dry non-freeze), construction number (CN), and several climatological data. After utilizing various ANN model structures, the best performing ANN model resulted in promising statistical measures (i.e. R2 = 0.87). The IRI prediction model can successfully estimate the increase of IRI values with the increase of ESAL value over time. The IRI prediction model can also estimate the decrease of IRI value after maintenance and rehabilitation. The predicted IRI values with good accuracy will help the local and state agencies to prepare for M&R programs for JPCP pavements and allocate a projected budget accordingly.
Assessment of Influence of Residential Area Planning Structure on Air Quality Using Numerical Modeling
Authors: Valger Svetlana , Maslova Anastasia
Published: December 2021

Numerical study of the aeration of a new urban microdistrict located along a highway in Novosibirsk, Russia, was performed. The main goal of the paper was to assess whether the architectural and planning structure of the new microdistrict is optimal in terms of aeration and air quality. A scenario of particulate matter (PM10) transfer in the vicinity of the microdistrict is reproduced. Numerical modeling is performed for the prevailing wind direction. 3D numerical simulation was carried out using the Revit software to build the CAD model of the residential area and the ANSYS software was used to perform a computational experiment. Based on the calculations, numerical data were obtained on the wind speed and on PM10 concentration fields in the residential area. Favorable and unfavorable zones of the microdistrict in terms of high concentrations of PM10 at the pedestrian zones were described.
Asphalt Concrete for Binder Courses with Different Jute Fibre Content
Authors: Gallo Peter , Valentin Jan , Mondschein Petr
Published: December 2021

Since the beginning of modern road construction, there have been effort to make durable, long life pavements. But no one pavement can fulfil designed purpose forever. On the other hand, some natural resources are limited, so it is important to maximize use of renewable resources. In recent years, there is a visible pursuit of this trend, in road construction represented mostly by use of waste materials, such as industrial by-products or recycled asphalt pavement itself. Within the effort, fibrous additives were established on the market to prolong life of pavement layers. Some commercial ones are synthetic polymer based, so it does not go well with the renewable part of pavement life cycle if we want to secure sustainable future. This paper describes use of fibres from natural renewable resource, specifically jute plant (Corchorus). Three asphalt mix variants with jute fibres were designed and further compared. Fibre content was 0.1 %, 0.2 % and 0.3 % by weight. Several tests were conducted to examine the effect of fibres on mixture properties, with aim on stiffness modulus (IT-CY) and crack propagation (SCB). Furthermore, indirect tensile strength ratio was calculated as a parameter showing performance of the mixture under the wet conditions. Control mixtures with paving grade and polymer modified bitumen were tested for better comparison and evaluation of the results.
A Comparison of Shell and Solid Finite Element Models of Austenitic Stainless Steel Columns in Compression
Authors: Jindra Daniel , Kala Zdeněk , Kala Jiří
Published: December 2021

The subject of this article is the implementation of new knowledge on material and geometric characteristics obtained from an experimental research program in advanced numerical modelling of compressed columns made of austenitic stainless steel using the ANSYS Classic software. Nonlinear stress–strain curves were obtained using our own experimental program and studied in terms of identifying the most suitable nonlinear material model. Additional material and geometric characteristics were obtained from literature and other independent research. Numerical models differing in mesh density localization, formulation of element integration, non-linear material model, and initial geometric imperfections were created and compared. The aim of the models was the ultimate limit state of a strut of circular hollow cross-section stressed by compression and analysed using the geometrically and materially nonlinear solution with consideration to the influence of initial imperfections. Static resistance and limit state deformations are compared for each model. The paper presents the analysis of model uncertainty by comparing SHELL and SOLID FE models, which must be characterized before the start of the analysis of the random influence of imperfections on the limit states. The mean values and the coefficients of variation are practically the same for both approaches. In summary, the presented models can be considered sufficiently validated and eligible for integration in tandem with simulation sampling methods.
Comparison of the Performance of Prestressed Ribbed Panels and Hollow Core Panels Supported on Four-Edges
Authors: Zając Jakub , Drobiec Łukasz
Published: December 2021

Tests of full-scale models of the precast slab with dimensions of 6.30 x 6.30 m, built of two different precast panels, were carried out under short-term load. The models were made of autoclaved aerated concrete (700 type) brick with a thickness of 240 mm and a height of 2.24 m. The slabs were supported at four edges. The first slab was precast prestressed ribbed panels with concrete overtopping. The second slab was made of prestressed hollow-core panels. The panels had the same modular width of 600 mm. Tests were carried out under load placed on the top of the slab. The short-term load was applied sequentially, and displacement measurements were measurement by the electronic method. The load was initially applied evenly distributed. In the last step, part of the load was transferred to one-half of the slabs. The obtained load was different for each half of the slab. The first part of the slab were panels 1 to 5, loaded with the value of 1.7 kN/m2, and the second part was panels 6 to 10 loaded with the value of 7.7 kN/m2. The tests allow determining the difference in slabs' performance depending on shear key construction. The panels maintained the possibility of load redistribution based on their interaction despite the longitudinal joints' work only through the concrete cross-section. The slabs had a different character of transverse displacements depending on the presence of concrete topping. The models revealed a different response to transferring part of the load to one-half of the slabs. There were no cracks in the line of longitudinal joints on the upper surface of the slabs. Also, there were no cracks on the bottom of the panels. At the panels' connection with the wall, rotation and lifting corners of the slabs were noticed. The measured displacements were significantly smaller than for the corresponding models of single-span slabs with a parallel load.
A Computer simulation of noise of construction machinery operating in parallel
Authors: Kantová Radka
Published: December 2021

Prolonged, repeated or very intense noise exposure can damage human health. To reduce any dangerous effects of noise on human health, policies and restrictions are enshrined in national law and legislative regulations. In the Czech Republic, this issue is subject to the Ministry of Health. In other states it can be the Ministry of Health or more often the Ministry of the Environment. The protection of human health against noise and vibration is enshrined in Act No. 258/2000 Coll., on Protection of Public Health, specifically in şş 30-34 of this Act. Other restrictions are described in Act No. 309/2006 Coll., which regulates other requirements for safety and health protection at work in labour relations and on ensuring safety and health protection in activities or the provision of services outside of labour relations. Furthermore, hygienic limits for workplaces, protected indoor areas of buildings and protected outdoor areas are set in the new Regulation of the Government of the Czech Republic, No. 272/2011 Coll. as amended. This Regulation also sets limits for construction noise. They set limitations in so-called outdoor protected areas and the so-called outdoor protected areas of buildings. The hygienic limit of the equivalent sound pressure level A for noise from construction activities is set here by adding a correction of 5dB or 15dB according to the type of protected space to the basic value of the equivalent sound pressure level A 50dB. This limit must be adhered to. For buildings nearby, the term „protected facades“ is used, i.e. „protected façades“ include the nearest buildings that are inhabited and their occupants could be exposed to noise for a long period of time. We can measure the intensity of noise in these places if we have a "sound level meter". Predicting the intensity of noise and its longevity for future construction is more challenging. The computational evaluation of the noise load of the outdoor area of the monitored territory is based on the recommended theoretical acoustic relations for the transmission of sound from stationary noise sources according to ČSN ISO 9613/1-2. One of the possibilities of calculating the intensity of noise is the application of software programmes used for determining traffic noise, which, in contrast to construction noise, is handled very carefully and predicted in detail during the construction of transport infrastructure. Because here are the values and methodologies for the calculation of noise indicators set correctly and in detail, it is possible to use them also, provided that we work well with the background and input data. The calculation indicators are the values of the equivalent sound pressure level falling in front of the façade, on which we determine various measuring points. If the noise sources and acoustically significant elements are entered correctly, we obtain both correct values and also the possibility of displaying a map of the area with colour isophone bands, which expresses the level of noise in the construction site and its surroundings.
Non-destructive Testing of Wooden Elements
Authors: Zielińska Monika , Rucka Magdalena
Published: December 2021

Examining the condition of wooden elements is crucial from the perspective of proper structure performance. If the deterioration in the internal wood condition, which displays no symptoms visible from the outside, is detected, the further spread of the deterioration can be prevented. Test results often point to the necessity of conducting repairs and, renovations, replacing the structure of wooden beams, or even substituting a significant part of the structure. To achieve acceptable results, test methods should take into account the anisotropic nature of wood, which includes the shape of annual rings, as well as the location of the core in crosssection. To adopt methods based on physical effects, profound knowledge of wood physics is needed, particularly of interdependence. Apart from simple tests such as a visual inspection or tapping that are used to determine near-surface defects, non-destructive testing (NDT) plays an important role in the process. This paper presents the methods of non-destructive testing of wooden elements. These methods include tests conducted with ground penetrating radar (GPR), thermal techniques, microwaves, acoustic emission, ultrasonic tomography, and X-ray tomography. The paper summarises the use of non-destructive methods, indicating their advantages, disadvantages as well as some limitations.
From Seismic Instrumentation Towards Disaster Prevention and Mitigation
Authors: Dragomir Claudiu Sorin , Dobre Daniela
Published: December 2021

The present paper describes the current technical achievements in seismic instrumentation and monitoring within a national network and the role of this developed concept in disaster prevention and mitigation, in particular case of Romanian seismicity. Many studies are being conducted in the field of structural health monitoring, for seismically instrumented/monitored buildings, based on existed sensor technology, seismic data acquisition systems, data communication and information flow, computer hardware/software engineering, new solutions for seismic data transfer etc. Seismic records in free-field and on buildings are capitalised in anti-seismic design, development of technical and technological solutions in construction, seismic evaluation and rehabilitation of buildings, as well as in the process of education and earthquake preparedness. It aimed also to create a virtual seismic network (through Internet, WAN property networks, public analogue telephone network). It is a national priority creating a preventive culture in order to mitigate the seismic risk, starting with the strengthening of buildings, upgrading of the code for seismic design, seismic instrumentation as a usual practice and continuing with public communication and information actions, empowering communities and decision-makers related to the risks, prevention measures, what behaviour to be adopted. The efforts of last years show that Romania has taken important steps in preparing a response according to the challenges induced by the existing seismic sources from the entire territory of the country.
Hydraulic Analysis of Design of Flood Protection Measures in Lowland Conditions
Authors: Šoltész Andrej , Mydla Jakub , Leško Peter , Honti Richard
Published: December 2021

The goal of the contribution is to analyse and review the possibilities of flood protection in hydrological, morphological and geological conditions of the East Slovak Lowland, specifically the flood protection of the county city Trebišov. The flood situation is caused very often by the Trnávka stream flowing along the city. The analysis was performed by mathematical modelling using HEC-RAS software. Based on Trnávka drainage basin reconnaissance, own measurements in situ and study literature relating thereto a proposal of several technical measures for safe run-off in the Trnávka river bed has been elaborated and consequently evaluated from hydraulic point of view.
Hydraulic Review of the Flood Protection Measures in Bardejov
Authors: Šoltész Andrej , Cubanová Lea , Mydla Jakub , Cerveňanská Michaela , Baroková Dana
Published: December 2021

The contribution is dedicated to hydraulic analysis of the flood protection of county town Bardejov in the north-east part of Slovakia where after numerous floods on the Topľa River the flood protection has been constructed just partially in the central residential area of the city (phase I.) Next phases II. and III., which append to phase I. upstream and downstream are currently in a process of evaluation, so the flood protection of the city is far from being complete. The submitted article deals with hydraulic assessment of realized flood protection measures and their impact on proposal of phases II. and III. Authors have solved the given problem using mathematical modelling of open channel flow for steady and unsteady conditions of flood discharge at really measured flood wave in the year 2010 which was very close to the value of Q100 water. At the same time, they have proposed flood protection measures on the Topľa River in localities which are not considered and not solved by present realized flood protection. Proposed flood protection measures downstream and upstream of the realized flood protection were proven by mathematical modelling in HEC-RAS software program and they should get under control even the historical flood which appeared in Bardejov City in 2010.
Mathematical Modelling to Control the Chemical Composition of Blast Furnace Slag Using Artificial Neural Networks and Empirical Correlation
Authors: Cardoso Wandercleiton , Barros Danielle , Baptista Raphael , Felice Renzo di
Published: December 2021

Portland cement additions have been used for many years with the main objective of reducing the amount of clinker. Among the additions, blast furnace slag, resulting from the production of pig iron, that is, reusing this by-product, reduces the emission of carbon dioxide as well as decreases the exploitation of natural limestone and clay reserves, which are raw materials for Portland clinker. In order to reduce these emissions and increase the availability of raw materials, research has been directed to study clinker-free binders, as is the case with activated alkali cements and supersulfated cements. In this way, alkali-activated cements can only involve the reuse of industry by-products and do not require the calcination of the raw material, thus reducing the emission of polluting gases into the atmosphere. Supersulfated cement are composed of up to 90% blast furnace slag, in addition to 10 to 20% calcium sulfate. One of the most important characteristics of blast furnace slag is the ratio of the content of CaO and SiO2, also known as the simplified basicity index (B2). This paper proposes the mathematical modeling of an artificial neural network to predict the final chemical composition of the blast furnace slag to be produced based on the operational parameters of the blast furnace aiming its use in the production of special cements such as alkali-activated cements and supersulfated cements. The high values of (R) associated with low values (RMSE) show the good statistical performance of ANN demonstrating that the mathematical model is efficient to carry out the forecast of the production of blast furnace slag.
Effects of Substrate Texture and Moisture Conditions on Ultra-High Performance Concrete and Silica Fume Concrete Overlay Bond Strengths
Authors: Toledo William K. , Newtson Craig M.
Published: December 2021

Direct tension tests were conducted to investigate the effects of substrate moisture conditions and texture on ultra-high performance concrete (UHPC) overlay bond strengths. Improper substrate surface preparation can result in inadequate bond strengths and, in severe cases, lack of bond. To demonstrate the importance of surface preparation, pull-off tests were performed on overlaid slabs that had two extreme substrate surface moisture conditions (saturated and dried) prior to overlay application. Saturated slabs had a tined, tined-light sand blasted, or tined-medium sand blasted substrate surface texture. Dried slabs had either a tined or an exposed aggregate surface texture. Saturated specimens with tined, tined-light sand blasted, and tined-medium sand blasted surface textures achieved average bond strengths of 0.924, 1.45, and 1.95 MPa, respectively. Dried substrate surfaced specimens had zero bond strength. Surface moisture conditions that ranged from saturated to dry were also investigated by allowing the substrate surfaces to dry for 15, 30, 45, and 60 minutes prior to application of an UHPC overlay. Tined-light sand blasted specimens with surfaces that dried for 15, 30, 45, and 60 minutes achieved average bond strengths of 2.86, 2.01, 1.59, and 0.165 MPa, respectively. Results showed tined-light sand blasted specimens with proper saturating achieved adequate bond strengths, and properly saturated, tined-medium sand blasted specimens produced excellent bond strengths. Results also exposed the drastic consequences of not maintaining a saturated substrate surface prior to overlay application and delaying overlay application up to 60 minutes can drastically reduce bond strength.
Acoustics of a School Building Made in Wooden Technology on the Example of Building from the Second Half of the 19th Century
Authors: Nowoświat Artur , Olechowska Marcelina , Żuchowski Rafał
Published: December 2021

The Władysław Matlakowski School in Zakopane was established in 1877. After the war damage, during the Communist rule in Poland the school was rebuilt and renovated. As a result, the original character of the classrooms was distorted. Fiberboards used for interior finishing changed the acoustic climate of the rooms. The reverberation time of the tested rooms considerably exceeds 2 seconds for low frequencies and is below 2 seconds for medium frequencies. Thus, the reverberation conditions do not differ from typical school classrooms in Poland. The tests of reverberation conditions were supplemented by the measurements of acoustic insulation of partitions separating the chool classrooms from each other and from the corridor. The studies allow to infer that the noise possibly comes from the corridors or adjacent rooms.
Costing, Adobe Technique as a Sustainable Construction System in the City of Cuenca
Authors: Molina Verónica , Angumba Pedro
Published: December 2021

Adobe is an old material used in construction but over time, this construction system has lost space and preference among population. Hence, the need to seek alternatives as professionals in the construction area to encourage the use of the Adobe technique has raised. Thus, the present study made a cost of the items involved in the construction of houses from the adobe based on the theoretical references. In addition, it established a unit price analysis that identifies the particularities of this system focusing on an analytical, descriptive-conclusive methodology whose data are analysed from the results of applying a survey (n = 96) to the inhabitants of the rural sector of Cuenca and construction experts (n = 11). The average price of the construction of houses with Adobe is $ 38,357.23 dollars for a house of 150 m2 taking into account that the real costs and the construction activity are sensitive to changes in the population and market prices.
Evaluation and Analysis of Unit Prices of a Rammed Earth Construction System
Authors: Ordoñez Hernán , Angumba Pedro
Published: December 2021

The tapial is part of the traditional construction worldwide, which uses environmentally friendly materials of natural origin such as raw earth, wood and water for its manufacture. The construction technique was used for the construction of habitable spaces, which are part of the ancestral construction system of our country; Despite the above, no updated studies on the costs required in the construction process have been identified in Ecuador. This is mainly due to the constant development of new technologies that introduce new construction systems to the market that use industrialized materials for their manufacture. Therefore, this document evaluated and analyzed the unit prices of the items involved in the construction of works using mud as its main component. Field and exploratory research was applied, through the application of surveys to a sample of 97 professionals of Civil Engineering and Architecture in the city of Cuenca, as well as 30 professionals with experience in construction of the indicated construction system. The Unit Price Analysis determined that the average cost of a 140 m2 typical house is $ 46,236.64 with an estimated cost of $ 330.26 per square meter; Similarly, the study determined a maximum cost of $ 53,172.14 USD with a value of $ 379.80 USD per square meter and a minimum value that represents $ 39,301.14 with a cost per square meter of $ 280.72.
Recommendations for Directing the Success of Roads Projects Management, Analysis of Triple Restriction
Authors: Armijos Edison Carlos Patiño , Quito Mercedes Gabriela Jaramillo
Published: December 2021

The present Project is developed in Ecuador, Morona Santiago Province as a response to prior research that determined the failure of projects execution is due to the poor management of restrictions set by the director project. This research constitutes a contribution to Scientific knowledge about Project Management, primary factors influencing the failure of projects and recommendations for the achievement of success on roads construction projects. In order to get the stablished objective in this study, it was necessary the analysis of the conditions on which roads projects were executed and completed over the years 2018, 2019, and 2020 by the Decentralized Autonomous Government of Morona Santiago on the modality of procurement, and it was also important to stablish the causes that contributed to a particular outcome on projects. The approach of the analysis is focused on the management of restrictions of costs, time, and scope (triple restriction) of projects in study. The technique that was used is the analysis of the content that was applied to contractual records of 81 hired projects by selection of minor amount, price, bid, reverse auction, and contingency plan according to the Ecuadorian legislation for public works procurement. For the record and further data analysis, the information was encoded identifying in contractual files the causes that directly or indirectly led to categories of costs management, time and scope of projects. The results achieved show the causes that contributed to the failure of projects and the state in which they were finished in terms of initially stablished costs, time and scope. The obtained information was the basis to come up with recommendations referring the good practices on projects management that will work people in charge of projects management of roads constructions in order to obtain success on future projects.
Microzonification of Floor with Sliding in Nulti Parish
Authors: Parra Diana del Rocío Urgiles , Noboa Juan Sebastián Maldonado , Sánchez Luis Mario Almache
Published: December 2021

Cuenca is located on three areas controlled by mega faults and 14 areas at risk from landslides. One of them is the Nulti community that registers landslides in 16 subzones during the past 10 years. The waters presence on the ground is one of the causes of these earth movements, and this generated infrastructural and environmental losses. According to the update of the Development and Land Management plan, the Santa Cecilia Pasto Romero neighborhood is one of the affected areas. This community is located in the Parish Center. This place lost a considerable number of houses and equipment like educational, health, religious, administrative infrastructure, because it has landslides of great magnitude. Given these antecedents, we carried out a study that allows to know the behavior of this soil against seismic waves and identify risk areas, their properties such as soil type, allowable loads, and elasticity modulus. In this way, the risks presented by these landslides were determined from a soil profile by processing the results of the Geophysical analysis like seismic refraction tests, standard penetration, and electrical soundings. This study generates future lines of research like slope stabilization and drainage designs. This study opens the possibility of being replicated in the other parishes of Cuenca. The subsoil presents a cohesive material with high plasticity. The soil has deposits with silty clay matrices of high plasticity. This mass of soil has been removed by the effects of landslides and colluvial deposits. Therefore, its low shear wave velocities expose loose soils of high plasticity and medium to high expansivity.
Classification of historical buildings based on energy efficiency tests and comfort tests
Authors: Fedorczak-Cisak Małgorzata
Published: December 2021

The article presents a proposal for the classification of historic buildings in terms of improving energy efficiency, ensuring the comfort of users and their impact on the environment. In the case of historic buildings, Polish law does not require energy efficiency improvement. The proposed classification also takes into account the function of the object and is largely based on "in situ" research. The presented model of classification will help users of historic buildings to undertake appropriate thermo-modernization measures to improve energy efficiency and comfort of use. In situ tests in historic buildings are of particular importance also for the correct diagnostics of this type of buildings.
Use of recycled materials in bricks
Authors: Krenzel Vladimír , Srek Jakub , Mikoláš Milan , Fiala junior Jan Bedřich , Fiala Jan
Published: December 2021

In our presentation we are trying to clarify possibility of adding recycled materials into bricks and to name the changes of characteristics of individual additives. When we remind that the first ceramic decorative figure was The Venus of Věstonice. Babylonian gardens, Hagia Sofia, one of the most beautiful churches that has ever been built. The great Wall of China – The biggest brick creation in the world, medieval castle Malbork built in northern Poland not far from Gdansk's bay which with its size resembles small town, Skyscraper Chrysler Building in New York. All of these buildings have one thing in common and that is material from which they were built. After obtaining this knowledge, we have known for 10.000 years. Many types of modification of full bricks followed. Then the advancement ensued.
Study Results and Achieving High Ventilation Air Quality in Architecture for a Public Utility Building – Shopping Centre in Mielec, Poland
Authors: Wrana Jan , Struzik Wojciech
Published: December 2021

The purpose of the current study is to utilise a novel technology that is expected to bring reductions in electrical and heat energy consumption and cut CO2 emissions in the shopping centre public utility building in Mielec. The building is equipped with systems for obtaining heat and cold from groundwater and features the energy consumption level of a passive building with the lowest primary energy ratio (PER) in Poland. This state-of-the-art, innovative, energy-efficient and environment-friendly FCH system with BMS control was subjected to numerous tests and analyses, the details of which will be presented further in this paper. The design assumptions were confirmed and all work parameters were recorded for the system under extreme conditions, including the determination of final energy (FE) and primary energy (PE).
Graph-domain features and their application in rotating machinery fault diagnosis
Authors: Gao Yiyuan , Du Wenliao , Gong Xiaoyun , Yu Dejie
Published: December 2021

To more effectively extract the non-stationary and non-linear fault features of mechanical vibration signals, a novel fault diagnosis method for rotating machinery is proposed combining time-domain, frequency-domain with graph-domain features. Different from the conventional time-domain and frequency-domain features, the graph-domain features generated from horizontal visibility graphs can extract the fault information hidden in the graph topology. Aiming at the problem that too many features will lead to information redundancy, the Fisher score algorithm is applied to select several of sensitive features which are then fed into the support vector machine to diagnose the faults of rotating machinery. Experimental results indicate features extracted from the three domains can be used to obtain higher diagnosis accuracy than that extracted from any single domain or dual domains.