Buildings

18 pages, 4700 KiB

Open AccessArticle

The Influence of 30 Years Outdoor Weathering on the Durability of Hydrophobic Agents Applied on Obernkirchener Sandstones

by Jeanette Orlowsky, Franziska Braun and Melanie Groh

Buildings 2020, 10(1), 18; https://doi.org/10.3390/buildings10010018 - 20 Jan 2020

Cited by 9 | Viewed by 3524

Abstract

The durability of eleven different water repellents applied on one sandstone type was studied after a long-term weathering at seven different locations in Germany. By measuring colour changes, it could be shown that the formation of black crusts, the deposition of particles and [...] Read more.

The durability of eleven different water repellents applied on one sandstone type was studied after a long-term weathering at seven different locations in Germany. By measuring colour changes, it could be shown that the formation of black crusts, the deposition of particles and biogenic growth caused a gradual darkening as well as significant changes in total colour over time. Additionally, the water absorption behaviour was investigated with two different methods: applying a low pressure using the pipe method and capillary water absorption measurements from a wet underlay. Afterwards, the test results were analysed with four different evaluation methods: calculation of the protection degree from pipe method and capillary water absorption, determination of the velocity of water uptake during capillary water absorption and calculation of the damaged depth of the stone surface using single-sided NMR technique. The growing damaged depth leads to an increase of the water uptake velocity and to a decrease of the protection degree of the applied hydrophobing agents. Three protective agents based on isobutyltrimethoxysilane showed already after two years of outdoor weathering a clear loss of performance, which significantly increased after 30 years of exposure. Full article

(This article belongs to the Special Issue Life Cycle Prediction and Maintenance of Buildings)

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6 pages, 237 KiB

Open AccessEditorial

Acknowledgement to Reviewers of Buildings in 2019

by Buildings Editorial Office

Buildings 2020, 10(1), 17; https://doi.org/10.3390/buildings10010017 - 20 Jan 2020

Viewed by 2770

Abstract

The editorial team greatly appreciates the reviewers who have dedicated their considerable time and expertise to the journal’s rigorous editorial process over the past 12 months, regardless of whether the papers are finally published or not [...] Full article

13 pages, 1115 KiB

Open AccessEditor’s ChoiceArticle

A SWOT Analysis of the Use of BIM Technology in the Polish Construction Industry

by Krzysztof Zima, Edyta Plebankiewicz and Damian Wieczorek

Buildings 2020, 10(1), 16; https://doi.org/10.3390/buildings10010016 - 20 Jan 2020

Cited by 47 | Viewed by 15081

Abstract

The present paper presents a SWOT analysis, the aim of which is to evaluate the strategic implementation of BIM technology in the construction industry in Poland. The authors created a SWOT matrix presenting strengths, weaknesses, opportunities, and risks associated with the use of [...] Read more.

The present paper presents a SWOT analysis, the aim of which is to evaluate the strategic implementation of BIM technology in the construction industry in Poland. The authors created a SWOT matrix presenting strengths, weaknesses, opportunities, and risks associated with the use of BIM. Using literature analyses, own experience, and market reports, all elements of the SWOT matrix are described in detail. Basic indicators characterizing the strategic position of BIM on the Polish construction market are calculated. Finally, the matrix of strategic tasks and actions that should be applied in order to promote and develop BIM in Poland are defined. Full article

(This article belongs to the Special Issue Architecture and Engineering: the Challenges - Trends - Achievements)

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18 pages, 6829 KiB

Open AccessArticle

Experimental and Computational Study of the Implementation of mPCM-Modified Gypsum Boards in a Test Enclosure

by Juan Pablo Bravo, Tomás Venegas, Elizabeth Correa, Alejandro Álamos, Francisco Sepúlveda, Diego A. Vasco and Camila Barreneche

Buildings 2020, 10(1), 15; https://doi.org/10.3390/buildings10010015 - 19 Jan 2020

Cited by 7 | Viewed by 3946

Abstract

The application of phase change materials (PCM) in the thermal envelope of buildings has proven to be an alternative to reduce energy consumption and to improve thermal comfort conditions. The present work evaluates the thermal behavior of gypsum boards modified with a microencapsulated [...] Read more.

The application of phase change materials (PCM) in the thermal envelope of buildings has proven to be an alternative to reduce energy consumption and to improve thermal comfort conditions. The present work evaluates the thermal behavior of gypsum boards modified with a microencapsulated PCM (mPCM) in a cubic test enclosure, considering the climatic conditions of Santiago de Chile in the September–November period of 2017. The design of the test enclosure was performed considering the minimization of parameters that affect the variation of its inner temperature and favoring the heat flow through the gypsum boards. Experimentally, the results reflect the main effects of the implementation of a mPCM, among which the displacement of the maximum heat load and the decrease in the daily oscillation of the internal temperature of the test enclosure (up to 2 °C) stand out. In addition, the mPCM modified gypsum board was thermally characterized to carry out a thermal simulation of the enclosures using EnergyPlus™. The obtained numerical results agree with those obtained experimentally, including the behavior of the transient heat flux through the gypsum boards. Moreover, it was found that considering a null infiltration rate gives place to unrealistic results, suggesting that this parameter should be controlled. Full article

(This article belongs to the Section Building Energy, Physics, Environment, and Systems)

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Graphical abstract

14 pages, 7202 KiB

Open AccessArticle

Characterization of the Mechanical Performance in Compression Perpendicular to the Grain of Insect-Deteriorated Timber

by Maxime Verbist, Jorge M. Branco and Lina Nunes

Buildings 2020, 10(1), 14; https://doi.org/10.3390/buildings10010014 - 19 Jan 2020

Cited by 12 | Viewed by 5766

Abstract

Among biological agents, insect attacks may cause severe degradation of timber structures in the service life of buildings which leads to lower mechanical performance and, thus, maintenance problems over time. Additionally, compression perpendicular to the grain always features a weak spot with respect [...] Read more.

Among biological agents, insect attacks may cause severe degradation of timber structures in the service life of buildings which leads to lower mechanical performance and, thus, maintenance problems over time. Additionally, compression perpendicular to the grain always features a weak spot with respect to the long-term mechanical performance of timber members and joints. In the present work, the respective strength and elastic modulus were thus investigated for insect deteriorated wood. Following a standardized geometry, small samples degraded by anobiids were extracted from beams made of sweet chestnut wood (Castanea sativa Mill.) that were removed from service. Visual assessment of the external wood surfaces was then performed to identify areas infested by insects. Afterwards, destructive monotonic compression tests were carried out perpendicularly to the grain on the damaged area to determine the loss of compressive strength and elastic modulus. The experimental results showed that the loss of compressive strength and elastic modulus might be linearly correlated to the wood density loss for small samples infested by insects. Nonetheless, future work should focus on determining accurately the density loss in the insect-deteriorated part through non- or semi-destructive tests, in order to establish stronger relationships with the mechanical properties loss investigated. Full article

(This article belongs to the Section Building Structures)

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12 pages, 1767 KiB

Open AccessArticle

Proposal of an Assessment Method of the Impact Sound Insulation of Lightweight Floors

by Łukasz Nowotny and Jacek Nurzyński

Buildings 2020, 10(1), 13; https://doi.org/10.3390/buildings10010013 - 16 Jan 2020

Cited by 2 | Viewed by 4208

Abstract

Lightweight floors are in line with a sustainable construction concept and have become increasingly popular in residential buildings. The acoustic performance of such floors plays a pivotal role in the overall building quality rating. There is, however, no clear and complete method to [...] Read more.

Lightweight floors are in line with a sustainable construction concept and have become increasingly popular in residential buildings. The acoustic performance of such floors plays a pivotal role in the overall building quality rating. There is, however, no clear and complete method to predict their impact sound insulation. A new approximation method and new acoustic indicators—equivalent weighted normalized impact sound pressure levels for lightweight floors—are proposed and outlined in this article. The prediction procedure and indicator values were initially validated on the basis of laboratory measurements taken for different lightweight floors with the same well-defined floor covering. These preliminary analyses and comparisons show that the proposed method is promising and should be fully developed on the basis of further research. Full article

(This article belongs to the Special Issue Advances in Sustainable Building Material Engineering)

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15 pages, 2725 KiB

Open AccessArticle

Simplified Design of Masonry Ring-Beams Reinforced by Flax Fibers for Existing Buildings Retrofitting

by Mariateresa Guadagnuolo and Giuseppe Faella

Buildings 2020, 10(1), 12; https://doi.org/10.3390/buildings10010012 - 15 Jan 2020

Cited by 16 | Viewed by 8006

Abstract

Seismic events have repeatedly highlighted the vulnerability of existing masonry buildings. Seismic retrofitting is frequently focused on improving the connection between walls and roof for ensuring behavior able to resist loads from any horizontal direction. This paper deals with the design of masonry [...] Read more.

Seismic events have repeatedly highlighted the vulnerability of existing masonry buildings. Seismic retrofitting is frequently focused on improving the connection between walls and roof for ensuring behavior able to resist loads from any horizontal direction. This paper deals with the design of masonry ring-beams made of clay bricks reinforced by natural fibers. Various solutions to ensure a masonry building box-behavior are possible, but this is a good combination of both static and conservation requirements, as it allows the use of bio-composites and grouts. It is a relevant possible alternative to the traditional reinforced concrete ring-beams, which are proven to be very ineffective under earthquakes. A simplified model for designing clay brick beams reinforced by flax fibers is provided, and a comparison with customary and traditional floor/roof masonry ring-beams is carried out. Full article

(This article belongs to the Section Building Materials, and Repair & Renovation)

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15 pages, 2973 KiB

Open AccessArticle

Mechanical Properties of Ultra-High Performance Concrete with Partial Utilization of Waste Foundry Sand

by Piotr Smarzewski

Buildings 2020, 10(1), 11; https://doi.org/10.3390/buildings10010011 - 14 Jan 2020

Cited by 28 | Viewed by 5277

Abstract

Waste foundry sand (WFS) is a ferrous and non-ferrous foundry industry by-product, produced in the amount of approximately 700 thousand tons annually in Poland and it is estimated that only a small percentage of this waste is recycled. The study used WFS to [...] Read more.

Waste foundry sand (WFS) is a ferrous and non-ferrous foundry industry by-product, produced in the amount of approximately 700 thousand tons annually in Poland and it is estimated that only a small percentage of this waste is recycled. The study used WFS to produce ultra-high performance concrete (UHPC) as a partial substitute for quartz sand. It was replaced with WFS levels of 0%, 5%, 10%, and 15% by weight of quartz sand content. The UHPC mixtures were produced and tested to determine the compressive strength, flexural strength, splitting tensile strength as well as the modulus of elasticity at 28, 56, and 112 days. Scanning electron microscope (SEM) analysis was done to identify the presence of various compounds and micro-cracks in UHPC with WFS. The results revealed an increase as well as an insignificant decrease in the mechanical properties up to 5% and 10% WFS replacement, respectively. These studies also prove improvement in the microstructure of UHPC up to a 5% WFS level. In all the tested properties in this work, 5% WFS was found to be an apt substitute for quartz sand. Full article

(This article belongs to the Special Issue High-Performance Concrete—Experimental Behavior and Structural Computational Modelling and Design)

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14 pages, 5812 KiB

Open AccessArticle

Risk of Moisture in Diffusionally Open Roofs with Cross-Laminated Timber for Northern Coastal Climates

by Agnieszka Sadłowska-Sałęga and Krzysztof Wąs

Buildings 2020, 10(1), 10; https://doi.org/10.3390/buildings10010010 - 14 Jan 2020

Cited by 5 | Viewed by 5740

Abstract

The paper is an attempt to answer the question whether the material-optimized roof construction using cross-laminated timber (CLT) is safe in terms of moisture content in the demanding northern costal climates. The proposed roof structure meets the strength requirements. The partition is diffusionally [...] Read more.

The paper is an attempt to answer the question whether the material-optimized roof construction using cross-laminated timber (CLT) is safe in terms of moisture content in the demanding northern costal climates. The proposed roof structure meets the strength requirements. The partition is diffusionally open, which facilitates moisture transport. However, there is a concern whether the applied layer system allows maintaining a safe level of moisture content below critical moisture content (CMC), which has been set at 20%. The article presents the annual hygrothermal calculation of the proposed roof slope for four locations of northern Europe and Greenland characterized by costal or subpolar climate. Four scenarios of indoor air relative humidity were considered: free floating, RHmin = 40%RH, RHmin = 50%, RHmin = 60%. In all cases, the minimum indoor temperature was 20 °C. The analysis was carried out using WUFI^®Plus software. The calculation results showed that the moisture content did not exceed 20% in the CLT layer at any of the described locations. However, for the two coldest climates the assumed level of safety has been exceeded in the roof oriented strand board (OSB) sheathing. Full article

(This article belongs to the Section Building Energy, Physics, Environment, and Systems)

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9 pages, 1332 KiB

Open AccessArticle

Value of Technical Wear and Costs of Restoring Performance Characteristics to Residential Buildings

by Beata Nowogońska and Jacek Korentz

Buildings 2020, 10(1), 9; https://doi.org/10.3390/buildings10010009 - 08 Jan 2020

Cited by 25 | Viewed by 3812

Abstract

Each building, over the course of subsequent years of use, undergoes wear, with a deterioration of its technical condition. As a result of this, the performance characteristics of a building decrease with the passing of time, with their complete or partial restoration requiring [...] Read more.

Each building, over the course of subsequent years of use, undergoes wear, with a deterioration of its technical condition. As a result of this, the performance characteristics of a building decrease with the passing of time, with their complete or partial restoration requiring repair and renovation works to be carried out. It is the task of real estate managers or owners to maintain the building in a non-deteriorating technical and functional condition. In order to preserve the technical and functional condition of a building at an adequate level, methodological support of decision-making processes pertaining to the conducting of rational maintenance management is necessary. The present article presents a proposal of a model allowing for the accurate assessment of the costs of renovation and repair works on a building at a given stage of its use, and their relationship with the value of the technical wear of the building in the same time period. Residential buildings constructed using traditional technology were subjected to analysis. In the carried out analysis, temporal methods applied for calculating the level of technical wear were applied, with the PRRD (prediction of reliability according to Rayleigh distribution) model of changes in the performance characteristics applied to determine the costs of renovation works necessary for restoring performance characteristics to the building. Full article

(This article belongs to the Special Issue Architecture and Engineering: the Challenges - Trends - Achievements)

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18 pages, 6653 KiB

Open AccessArticle

Experimental Study of Thermal Buoyancy in the Cavity of Ventilated Roofs

by Nora Schjøth Bunkholt, Toivo Säwén, Martina Stockhaus, Tore Kvande, Lars Gullbrekken, Paula Wahlgren and Jardar Lohne

Buildings 2020, 10(1), 8; https://doi.org/10.3390/buildings10010008 - 07 Jan 2020

Cited by 11 | Viewed by 4141

Abstract

Pitched wooden roofs are ventilated through an air cavity beneath the roofing in order to remove heat and moisture from the roof construction. The ventilation is driven by wind pressure and thermal buoyancy. This paper studies ventilation driven by thermal buoyancy in the [...] Read more.

Pitched wooden roofs are ventilated through an air cavity beneath the roofing in order to remove heat and moisture from the roof construction. The ventilation is driven by wind pressure and thermal buoyancy. This paper studies ventilation driven by thermal buoyancy in the air cavity of inclined roofs. The influence of air cavity design and roof inclination on the airflow is investigated. Laboratory measurements were carried out on an inclined full-scale roof model with an air cavity heated on one side in order to simulate solar radiation on a roof surface. Equipment to measure temperature was installed in the roof model, while air velocity in the cavity was determined by smoke tests. Combinations of different roof inclinations, air cavity heights and applied heating power on the air cavity top surface were examined. The study showed that increased air cavity height led to increased airflow and decreased surface temperatures in the air cavity. Increased roof inclination and heating power applied to the roofing also increased the airflow. The investigations imply that thermal buoyancy in the air cavity of pitched roofs could be a relevant driving force for cavity ventilation and important to consider when evaluating the heat and moisture performance of such a construction. Full article

(This article belongs to the Section Building Energy, Physics, Environment, and Systems)

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21 pages, 8294 KiB

Open AccessArticle

STATUS App: A Mobile Data Collection Tool for Buildings Adjacent to Tunneling Works

by Gianfranco Di Pietro, Fabio Rinnone, Claudia M. Parisi, Salvatore Caprì and Giovanni Bianco

Buildings 2020, 10(1), 7; https://doi.org/10.3390/buildings10010007 - 31 Dec 2019

Cited by 4 | Viewed by 5233

Abstract

In urban areas, tunneling works inevitably interfere with the adjacent buildings. In the preliminary design stage, designers usually do not inspect buildings adjacent to the construction sites, because these activities are often too expensive. This paper presents the STATUS app, an Android application [...] Read more.

In urban areas, tunneling works inevitably interfere with the adjacent buildings. In the preliminary design stage, designers usually do not inspect buildings adjacent to the construction sites, because these activities are often too expensive. This paper presents the STATUS app, an Android application for mobile data collection. It was developed and tested by Geofunction Srls before the beginning of the tunneling works for the railway doubling in Cefalù (Italy). The system assists technicians during visual inspections and records the pre-existing architectural and/or structural damages in buildings adjacent to construction sites in real time. The output of the data collection is an official report printed and countersigned in situ by the technicians and the owners of the inspected property. The application was used for 1189 inspections inside 96 buildings. The aim of the paper is to show the benefits achieved through the use of STATUS app. It is also useful for several purposes: external risk assessment, damage prevention, damage reporting, preventing future legal disputes, and the free-rider problems. The application is released under closed-source license. Full article

(This article belongs to the Collection Construction Management – Future Innovations, Methods, Techniques and Technologies)

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16 pages, 1733 KiB

Open AccessArticle

Housing Prices in Unregulated Markets: Study on Verticalised Dwellings in Santiago de Chile

by José Francisco Vergara-Perucich and Carlos Aguirre-Nuñez

Buildings 2020, 10(1), 6; https://doi.org/10.3390/buildings10010006 - 31 Dec 2019

Cited by 20 | Viewed by 5705

Abstract

Chile faces a housing affordability crisis, given that most of the population is unable to secure a house. While housing prices between 2008 and 2019 increased by 63.96%, wages only increased by 21.85%. This article presented an analysis of the housing price configuration [...] Read more.

Chile faces a housing affordability crisis, given that most of the population is unable to secure a house. While housing prices between 2008 and 2019 increased by 63.96%, wages only increased by 21.85%. This article presented an analysis of the housing price configuration for the main borough in the country—Santiago. The assessment focused on verticalised housing constructed between 2015 and 2019. The article developed an exploratory study on the price of housing in Santiago to generate a diagnosis to identify the role played by expectations of profitability when configuring price. Based on the information generated, we sought to contribute to the discussion on public policies that advance the development of affordable housing in central boroughs with high urban value, as is the case for Santiago’s borough of Greater Santiago. We hypothesised that profit expectation of real estate developers plays a key role in the housing prices, and an adjustment in the profit ratios might increase the affordability while keeping the housing market above profitable rates. This research addressed the lack of data transparency in the Chilean housing market with archival research, reconstructing costs and earnings from projects based on official registrations of transactions at the borough level. In Chile, the access to investment costs, land values, yields, and house price formation are not publicly available, even though these factors imply that many households are facing severe difficulties in paying for and accessing decent housing. Full article

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22 pages, 6705 KiB

Open AccessArticle

Heat Supply Comparison in a Single-Family House with Radiator and Floor Heating Systems

by Amir Vadiee, Ambrose Dodoo and Elaheh Jalilzadehazhari

Buildings 2020, 10(1), 5; https://doi.org/10.3390/buildings10010005 - 30 Dec 2019

Cited by 6 | Viewed by 7398

Abstract

Floor heating and radiators are two of the most common types of hydronic heating systems used for space heating in single-family houses in cold climate regions. Notwithstanding, there are few comparative studies on indoor temperature distribution and system cost evaluations for radiators and [...] Read more.

Floor heating and radiators are two of the most common types of hydronic heating systems used for space heating in single-family houses in cold climate regions. Notwithstanding, there are few comparative studies on indoor temperature distribution and system cost evaluations for radiators and floor heating. Furthermore, there are no aligned outcomes in terms of total heat supply for a single-family house with radiators or floor heating. In this study, the effect of building energy efficiency level and construction type, including flooring material, on the supply heating demand and transmission heat losses were studied for both radiator and floor heating systems. For this purpose, a single-family house located in Växjö, Sweden, was modeled as a case study. The heating demand was supplied with a district heating system with a similar supply temperature at 45 °C for both the radiator and floor heating system. A sensitivity analysis was also performed to assess the effect of flooring configurations on the annual supply heating demand for both conventional and passive versions of the case-study building. The results showed that the radiator-integrated building had a lower supply heating demand in comparison with the floor heating-integrated buildings. Based on the sensitivity studies, the flooring material did not have a significant influence on the supply heating demand and on the transmission heat losses in the case of the radiators. The supply heating demand was only reduced up to 3% if the flooring U-value was improved by 60%. The results also showed that refurbishment in a standard conventional building with a radiator heating system based on the passive criteria led to a 58% annual energy savings, while this amount for a building with a floor heating system was approximately 49%. Full article

(This article belongs to the Special Issue Sustainable Built Environment: Advanced Ventilation and Energy Efficient Technologies)

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16 pages, 1050 KiB

Open AccessArticle

Methods for Determining Mold Development and Condensation on the Surface of Building Barriers

by Aleksander Starakiewicz, Przemysław Miąsik, Joanna Krasoń and Lech Lichołai

Buildings 2020, 10(1), 4; https://doi.org/10.3390/buildings10010004 - 30 Dec 2019

Cited by 6 | Viewed by 4986

Abstract

The article presents four equivalent methods for checking mold growth on the surface of building barriers and checking water vapor condensation on their surface. Each method applies to two parallel phenomena that may occur on a building barrier. The first method is to [...] Read more.

The article presents four equivalent methods for checking mold growth on the surface of building barriers and checking water vapor condensation on their surface. Each method applies to two parallel phenomena that may occur on a building barrier. The first method is to calculate and compare temperature factors. In the second method, the characteristic humidity in the room is calculated and compared. The third method is to calculate and compare the characteristic temperatures in the room. The fourth method is based on the calculation and comparison of characteristic water vapor pressures. Three boundary conditions are presented for each method and phenomenon: when a given phenomenon can occur, when it begins or ends, and when it does not occur. The presented methods systematize the approach to the problem of mold development and surface condensation. The presented calculation results relate to the selected building barrier functioning in specific indoor and outdoor climate conditions. The calculation results confirm the compliance of the presented methods in identifying the phenomenon of mold growth or condensation on the surface of the barrier. A graphical interpretation of the results for each method with periods of occurrence or absence of a given phenomenon is also presented. Full article

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13 pages, 4458 KiB

Open AccessArticle

Monitoring and Assessing the Dynamics of Building Deformation Changes in Landslide Areas

by Lucyna Florkowska, Izabela Bryt-Nitarska, Rafał Gawałkiewicz and Janusz Kruczkowski

Buildings 2020, 10(1), 3; https://doi.org/10.3390/buildings10010003 - 30 Dec 2019

Cited by 3 | Viewed by 3580

Abstract

The paper presents the procedure and results of monitoring conducted by using a 3D measurement model, taking advantage of integrated surveying technologies developed for a building located within an activated landslide area. Geodynamic interactions within the building have resulted in a spatial deformation [...] Read more.

The paper presents the procedure and results of monitoring conducted by using a 3D measurement model, taking advantage of integrated surveying technologies developed for a building located within an activated landslide area. Geodynamic interactions within the building have resulted in a spatial deformation condition, leading to significant cracks of structure components and local basement floor upheavals. Conducted site research shows a reactivation of an old landslide form. To provide safe use conditions for the building, it was decided to monitor the structure and the area in its vicinity. Meeting this demand required developing an in-house monitoring system for the landslide form and the very structure. Measurements provided detailed information on the sizes and directions for the displacements of ground surface points and building structure points, as well as the dynamic properties of this phenomenon. Obtained results show the opportunity to use monitoring systems to acquire credible measurements data reflecting the real impact of ground landslide deformations on structures. Full article

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17 pages, 1724 KiB

Open AccessArticle

On the Search of Models for Early Cost Estimates of Bridges: An SVM-Based Approach

by Michał Juszczyk

Buildings 2020, 10(1), 2; https://doi.org/10.3390/buildings10010002 - 19 Dec 2019

Cited by 20 | Viewed by 4192

Abstract

The completion of a bridge construction project within budget is one of the project’s key factors of success. This prerequisite is more likely to be achieved if the cost estimates, especially those provided in the early stage of a project, are realistic and [...] Read more.

The completion of a bridge construction project within budget is one of the project’s key factors of success. This prerequisite is more likely to be achieved if the cost estimates, especially those provided in the early stage of a project, are realistic and close to the actual costs. The paper presents the research results on the development of a cost prediction model based on machine learning, namely the support vector machines (SVM) method, for which the input represents basic information and parameters of bridges, available in the early stage of projects. Several SVM-based regression models were investigated with the use of data collected for a number of bridge construction projects completed in Poland. Having finished the machine learning and testing processes, five of the models, of satisfying knowledge generalization ability and comparable performance, were preselected. The final selection of the best model was based on the comparison and analysis ability to predict bridge construction costs with accuracy appropriate for the early stage of projects. The general testing metrics of the finally selected model, named BCCPM_SVR2, were as follows: root mean square error: 1.111; correlation coefficient of real-life bridge construction costs and costs predicted by the model: 0.980; and mean absolute percentage error: 10.94%. The research resulted in the development and introduction of an original model capable of providing early estimates of bridge construction costs with satisfactory accuracy. Full article

(This article belongs to the Special Issue Architecture and Engineering: the Challenges - Trends - Achievements)

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14 pages, 786 KiB

Open AccessArticle

Holistic Analysis of Waste Copper Slag Based Concrete by Means of EIPI Method

by Wojciech Kubissa, Roman Jaskulski, Damian Gil and Iwona Wilińska

Buildings 2020, 10(1), 1; https://doi.org/10.3390/buildings10010001 - 19 Dec 2019

Cited by 7 | Viewed by 3962

Abstract

The aim of the research is a comprehensive evaluation of concrete using the EIPI method. In the evaluation the compressive strength of concrete and its durability properties represented by sorptivity and air permeability are taken into account. Since waste copper slag with increased [...] Read more.

The aim of the research is a comprehensive evaluation of concrete using the EIPI method. In the evaluation the compressive strength of concrete and its durability properties represented by sorptivity and air permeability are taken into account. Since waste copper slag with increased natural radioactivity is used in the assessed concrete, additional evaluation is carried out taking into account the influence of natural radioactivity within the performance index. Additionally, the reference concrete, which is made without the use of waste copper slag, is evaluated for comparative purposes. In order to make the evaluation as comprehensive as possible, the concrete made with the use of three types of cement is subjected to CEM I, CEM II and CEM III assessments. If natural radioactivity is not taken into account in the evaluation, the best result of the most favourable value of Gross Ecological and Performance Indicator (GEPI) is obtained by the concrete made with waste copper slag, and if radioactivity is considered, the most favourable value of GEPI is obtained with concrete without addition of the waste. The results show that in both approaches the best result is achieved by concrete with CEM III cement. It follows from the above that although natural radioactivity has a significant impact on the EIPI evaluation result, the decisive factor is still the type of cement. Full article

(This article belongs to the Special Issue Architecture and Engineering: the Challenges - Trends - Achievements)

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