Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

The aim of this study is to comparatively evaluate the eco-efficient performance of the only two mandatory thermal regulations applied in Chile: The General Urban Planning and Construction Ordinance (OGUC), and the Atmospheric Decontamination Plans (PDA). Considering the PDA of the communes of Temuco and Padre las Casas, and the system limits of UNE-EN 15978:2012 for the "product" and "use" stages, this study covered the indicators of energy, carbon footprint, economic cost and emissions of fine particulate matter (PM2.5), on thermal envelopes of a house. Applying the PDA over the OGUC, the results indicate that: First, the contained energy increases by 12.4%, the carbon footprint by 8.1% and the economic cost by 7.8% in the stage of product; and second, it reduces the demand for heating, fuel consumption, carbon footprint, and PM2.5 emissions, by 19.4%, in the use stage. Finally, the study concludes that, for Chilean homes to improve their eco-efficient performance, an evaluation with a life cycle cost analysis (LCCA) approach, which allows analyzing their evolution over time, must be included in the mandatory thermal regulations that regulate them.

Owning a house is one of the most important decisions that low and middle income people make in their lives.  The real estate market is a significant factor of the national economy as much as it is important for individuals.  Therefore, predicting real estate values or real estate valuation is beneficial and necessary not only for buyers, but also for real estate agents, economists and policy makers. This issue represents an active area of research, as individuals, companies and governments hold considerable assets in real estate. In this context, the aim of the study is to predict real estate prices with Machine Learning methods using the real estate sales data set in June and July 2021 belonging to the province of Ankara. In particular, it is to perform a comprehensive comparison on Machine Learning regression types methods that give successful prediction results in various but similar tasks, which are not included in the real estate literature. Real estate data obtained over the Internet was first included in a detailed data preprocessing process, and then Linear, Lasso and Ridge Regression, XGBoost and Artificial Neural Networks (ANN) methods were used on this dataset.  According to empirical findings, XGBoost and ANNs appear as very important alternatives in predicting real estate sales prices.

Incorporating fibers into the soil is a reinforcement remediation technique to improve its physical and mechanical properties. Depending on the type of fibers, synthetic fibers, have negative impacts on the environment linked to the waste of their chemical industry. Currently, vegetal fibers consider an economic and ecological alternative to soil reinforcement. Therefore, this study aims to evaluate the influence of two types of randomly distributed fibers (Alfa and Sisal fibers) on the mechanical properties of sandy soil. Direct shear tests were performed on Chlef sand at relative density (Dr = 75% and 40%) and of fiber contents varying from 1, 2, 3 and 4% for sand samples reinforced with Alfa fibers and 0.1, 0.3, 0.5 and 0.7% for sand samples reinforced with Sisal fibers. The test results show that the inclusion of vegetal fibers in sandy soil improves the peak and residual shear strength. In addition, soil resistance was found to attain a maximum with the optimums of 0.7% for sisal fiber content and 3% for Alfa fibers.

This study aims to introduce an earthquake-induced damage classification approach for seismic vulnerability assessment of reinforced concrete buildings. Through the use of the damage data collected from post-earthquake inspections after the 2003 Bingöl Earthquake in Turkey, two models were constructed by the decision tree classification technique considering nine building-specific features as the estimation variables in the analysis. The first model was developed for the prediction of the observed damage states of the buildings, whereas the second one concerning the life safety level assessment, was proposed for distinguishing the extremely vulnerable buildings for seismic prioritization. In the validation process, the leave-one-out cross validation technique was adopted to deal with the small sample size of the building inventory. Among the estimation variables, the priority index and the existence of short columns were found to have the highest importance in classification. Results have revealed that the proposed model for life safety level assessment was capable of discriminating the cluster of severely damaged and collapsed buildings from the entire database with an accuracy of 70.59%. Hence, the damage classification approach adopted in this study has the potential for improving effective tools for seismic risk assessment of the existing buildings.

  Recently, the semi-active control of structural vibration has demonstrated its ability to preserve human life and keep structures safe during earthquakes. In the civil engineering area, the literature is full of investigation in both numerical and experimental research in which the Magneto-Rheological damper is the most used device. This paper investigates the semi-active control of three scaled excited structures. The proposed control is assured by a Magneto-Rheological damper controlled using a hybrid Fuzzy Sliding Mode controller. Although, a Clipped optimal algorithm is proposed to calculate the required current for the damper operating. Otherwise, the robustness of the suggested controller is proved by the obtained numerical results of the seismic excited scaled structure. Therefore, the tested structure is subjected to four time-scaled earthquake records. Finally, the effectiveness of the proposed semi-active control strategy in mitigating earthquake structural vibration is shown clearly in the compared controlled and uncontrolled responses. The simulation results show that the peak reduction reaches 65% under the 2011 Tōhoku earthquake. In addition, the performance indices prove the robustness of the proposed strategy.

In this research, chemical durability performances of the alkali-activated slag (AAS), 50% ground granulated blast furnace slag and 50% fly ash (AFS), ordinary Portland cement (OPC), and geopolymer (GPC) concretes were investigated thoroughly under 5% sulfuric acid attack. All alkali-activated concrete specimens were produced considering the minimum binder content of 360 kg/m3 and the maximum alkali activator to binder ratio of 0.45 according to the XA3 environment given in EN 206-1 standard for OPC concrete. The visual inspection, weight change and compressive strength tests were performed to understand the influence of sulfuric acid attack on the resulting performances. Also, scanning electron microscope (SEM) and energy dispersive X-ray spectrometry (EDS) analyses were performed to examine the morphological variations in micro-scale. The mechanical performances and durability of alkali-activated concretes were also compared to the OPC concrete for structural utilization. The results revealed that AFS specimens showed the best durability, while GPC specimens exhibited the poorest durability. SEM/EDS results pointed out that AFS specimens exhibited denser and less porous microstructure, and the reductions in Al/Si and Ca/Si atomic ratios were observed under 5% sulfuric acid attack. In contrast, GPC specimens showed less dense and porous microstructure, and high aluminum leaching was observed. In addition, the wider interconnected macro cracks and high calcium leaching were observed in the AAS samples under 5% sulfuric acid attack. Finally, the AAS and AFS specimens can be utilized in structural applications, while GPC specimens should not be used with a minimum binder content proposed by EN 206-1 standard.

Total Quality Management could be defined as a transformation in management style aimed at constantly increasing customer satisfaction via the design and improvement of organizational systems and processes. It is critical to use an industrialized building system to increase project successful implementation. Awareness of TQM advantages and its application could greatly improve project efficiency and performance. A literature search on TQM was done to determine the TQM implementation present state and level of awareness in IBS construction projects. The purpose of this study is to identify the current TQM implementation status in IBS projects and determine its level of awareness and potential benefits from the Malaysian construction stakeholders’ perception. A mixed approach was applied in this research with the participation of consultants, contractors, clients, and academicians from various construction industry public and private sectors in Malaysia. The questionnaire survey was used to conduct the study. A total of 371 questionnaires were collected, for a sample size of 265. The findings indicated that most construction organizations are unaware of the TQM approach. The Cronbach's Alpha coefficient achieved from the study was (0.934), indicating that the questionnaire was reliable. The statistical analysis revealed that increased efficiency, improved customer satisfaction, enhanced teamwork, increased profitability, and improved safety are the most essential TQM benefits that concerned the participants. Furthermore, the results of this study provide IBS construction practitioners with significant awareness of the components that empower TQM implementation in the construction sector. This study contributes to the understanding of TQM and project performance by demonstrating their capacity to enhance the Malaysian construction sector. Additionally, it was found that the Malaysian construction industry has not achieved a high level of quality implementation programs.

In this study, use of end-of-life tires (ELTs) in self-consolidating concretes (SCC), which enable higher rates of fiber use than conventional concrete due to its superior flow properties, for the elimination of the environmental negative impacts and recycling of them were aimed. Besides, it is aimed to investigate the behavior of waste steel wires with different aspect ratio obtained from different types of tires, contrary to what is mostly researched in the literature. Therefore, bead, cord and base wires, obtained from tires, were used in high-strength self-consolidating concrete (HSSCC) production as fiber reinforcement. Fresh and hardened state properties of the waste wire-reinforced (1-2-3%) samples of different sizes that were produced, were compared with industrial steel-reinforced and non-fibrous samples. In this regard, slump flow and T50 durations were determined, compression and bending tests were performed. Significant improvements in the mechanical properties of conventional concretes were observed with the use of waste wire. Using the optimum ratio of waste wire, an increase of approximately 102% in flexural strength and 14% in compressive strength was observed compared to the reference specimen. Aspect ratio was recognized as one of the most effective factor on optimum fiber content. Moreover, experimental results were analyzed with "paired sample t-test", and it was seen that there were no considerable differences in the mechanical properties of the samples in which industrial fiber and waste-wire had been used. Besides, cost analysis was carried out to assess the economic benefits of the use of waste tire wires in the concrete industry.

In this study, biomass ashes from different energy valorization processes and storage conditions were used to make fire-resistant materials. Some of the ashes were subjected to a carbonation process. An 80/20 ash/gypsum ratio was used in all compositions. The density and different mechanical properties (compressive and flexural strength, superficial hardness, and dynamic modulus of elasticity), as well as fire resistance properties (insulating capacity and heat absorption capacity), were evaluated at 28 days. The energy valorization had a great influence on the particle size and the Loss On Ignition (LOI) of the fly ash. By increasing both, materials with lower mechanical properties (90%) were produced. Fire resistance was similar for the different ashes tested, but 50% lower than the gypsum material. When the ashes of the materials were carbonated, the material increases compressive strength by 400% compared to ashes without the carbonation process, and the fire resistance was similar to those materials composed exclusively of gypsum, but also a source of CO2 capture is produced.

This study investigated the frost resistance of concrete exposed to sulfate and acid attacks after two years. The cement content was selected as 300 kg/m3, 350 kg/m3, 400 kg/m3, 450 kg/m3, and 500 kg/m3 in this study. 100 mm cubic specimens were prepared for experiments. After the specimens were cured in the water at 20 ± 2 °C for 28 days, they were kept in the laboratory conditions at 20 ± 2 °C for 23 months+2 days. Then, these samples were subjected to freeze-thaw cycles after being exposed to 5% sodium sulfate, 5% magnesium sulfate, 1% sulfuric acid, and 2% sulfuric acid for four days. Thus, the samples were exposed to the four different combined attacks. Lastly, the mechanical properties, weight change, and relative dynamic modulus of elasticity of these specimens were determined. Furthermore, the SEM and EDS analyses were carried out on samples. This study found that the highest compressive strength, the highest ultrasonic pulse velocity, and the lowest weight loss were the samples with 500 kg/m3 cement content subjected to combined freeze-thaw and 1% acid attack.