Since oral communication is the main means we use to learn, acoustics becomes one of the most important attributes of the architectural design of classrooms. Adverse acoustic conditions in the classroom negatively affect the learning, performance and cognitive development of students. In year 2015 the Ministry of Education introduced acoustic design criteria for learning spaces. This article presents a review of these criteria based on a comparison with international regulations and considering the database of the Santiago’s urban noise map. The results show that the current acoustic criteria for educational settings in Chile present several shortcomings with respect to international standards. It is also observed that more than 70% of educational establishments in Santiago are exposed to environmental noise levels that lie outside the range of application of the criterion
The aim of this paper is to evaluate, through bending tests, the structural behavior of reinforced concrete beams additionally reinforced by bamboo splints. The bamboo splints are prepared from the stems of the Bambusa vulgaris species. To examine the strength of adhesion between the bamboo splint and concrete, pull out tests are performed for the specimens. The results of the pullout tests of the test samples show the strengthening of the nodes leading to an increase of the normal tension and rupture of splint and not its slip. According to the results of the bending beams, the presence of bamboo splints increases their load capacity when compared with the reference beams. This is indicative of a reduction in the amount of steel required as the structural element. The insertion of the bamboo splints in the beams provides a better performance in terms of the deflection and also leads to a slight increase in the load capacity of the beams. It is worth mentioning that the beams additionally reinforced by bamboo splints exhibit the same pattern of cracking as for reference beams
The phenomenon of fatigue can be considered as one of the main causes of the asphalt surface course failure. The Four Point Bending Apparatus is the widespread equipment used to determine the fatigue resistance of asphalt mixtures. Worldwide there are several standard procedures that rule this test. The main difference between them remains in the waveform, in which the load is applied, and in the failure criteria. This paper reports the influence from the waveform, haversine or sinusoidal, on the fatigue resistance of an asphalt mixture. In addition, through numerical simulation, it was evaluated the influence of the models obtained in the design of the thickness of the asphalt layer required for the structure of a pavement. The conclusion is that the use of haversine waves in fatigue tests results in a fatigue life of the asphalt surface layer almost 67 times bigger than the ones found on sinusoidal tests
The high level of competitiveness in the civil construction sector, together with the high level of customer demands, has led companies to explore and implement improvements in production processes to ensure the delivery of the established deadlines and quality of the products. In this way, a large number of construction companies have adhered to improvement programs in the construction processes, some of them being the implementation and certification of the quality management system (QMS), as well as the structuring of the planning and control system. of Last Planner production (LPS). In this context, this work aims to analyze the integration of the LPS and the method of continuous improvement of the QMS in a work in Colombia that has already implemented these systems. Initially an analysis of the systems in the work was carried out, in order to know the results of the implementation of these systems. Then, engineer managers of the systems in the company were interviewed where the negative and positive points of the integration were identified. With this study it is concluded that the integration of the systems brings significant improvements in the quality, time and cost established.
This article evaluated mechanical behavior of ultra-high performance concrete (UHPC) reinforced with hybrid steel and polypropylene fibers, with cement consumption of 250 kg/m³ and application of confining pressure in fresh state. The consistency of the mixture was analyzed, as well as mechanical properties of compressive strength, flexural strength and toughness. The percentages of hybridization were 50 to 100% of metal fibers and 0 to 50% of polypropylene fibers. Results showed that the compressive strength of the composite was 180 MPa (26100 psi), despite its low cement consumption of 250 kg/m³ (2.08 lb/gal), with 80% steel fibers and 20% polypropylene fibers. The combination of fibers increased the mixture’s toughness. For the composition with 80% steel fibers and 20% polypropylene fibers, the strength for large deformations increased by 191% compared with the mixture with 100% steel fibers, pointing out the benefits of hybridization
Every day, the BIM Methodology (Building Information Modeling) is getting closer to the companies and other members of the AEC sector (Architecture, Engineering and Construction), as well as to educational institutions that are starting to train new professionals on this matter. The roadmap set by the es.BIM Commission establishes the mandatory use of BIM for all public construction tenders as of December 17th, 2018 and for infrastructure tenders as of July 26th, 2019. The purpose of this paper is to make public and share the results of the research work concerning the state of implementation of BIM at different universities and Industrial Engineering Schools in Spain. However, are Spanish universities prepared for the challenge? Are teachers prepared for this? And what about the situation in Latin America? The study undertook a bibliographical review and analysis of publications addressing this topic, and talks given in specialized conferences. Different teaching experiences were analyzed and compared among several Spanish universities, and the problems encountered, the results obtained, future improvements and needs detected in relation to their implementation processes and procedures, have been taken into account
This paper presents the economic structural optimization of the Casa Síndico project using an algorithm programmed through the CSi API functions SAP2000v19-MATLAB R2015a, applying metaheuristic techniques: Genetic Algorithms (GA) and Particle Swarm Optimization (PSO), in addition to hybridization between them. The results show that PSO has a better performance than GA for this type of optimization, although both, working with their simple methodologies, are not completely efficient, which is verified when creating and applying a hybridization between the two, using GA to create an initial swarm for PSO to carry out the optimization process, obtaining results of up to 10% better. Regarding the structural results, a direct cost of construction is obtained by 13% more economical when applying the proposed methodology, leaving, for the beams, heights of relation L / h between 15 and 17.5, for the columns, the use of sections with rectangularities of up to 1.35, in the direction that more flexion occurs, something similar to what happens for the foundations, where the rectangularity of these follows the previous criterion, obtaining values of up to 1.4
This article describes and proposes a model of the force versus elongation behaviour of asymmetrical connections prone to bolt failure when subjected to quasi-static axial load. 14 connections were assembled with one bolt varying the distance from the bolt to the edge of the clamped zone, and 14 connections were assembled with two bolts varying the distance between bolts. Results show that the axial force versus elongation behaviour of the connection is approximately trilinear, that while the connection stiffness is not sensitive to the bolt location in the clamped zone, the plastic elongation of the connection is. The model shows that the stiffness of the asymmetrical connection can be predicted from the stiffness of the connection components assessed by means of spring elements or beam elements, and that the load capacity of the connection can be predicted using the dry friction theory of Coulomb and the shear bolt capacity.
Monitoring and control of large size civil works was an important and well known application area for topographical and geodetic methods, with a wide range of articles published. However, documented experiences applying precision geodetic methods in monitoring in a smaller scale (structural elements: beams, columns, slabs, etc.) are sparse. The main objective of this study is to evaluate and compare the use of precision geometric levelling technique with instrumentation with displacement transducers (structural instrumentation method) in vertical displacement control in a concrete beam with excessive deformation, being subjected to recovery processes and reinforcement. Although precision geometric levelling is not considered a modern technique in the structures monitoring, it is cost-effective feasible, accurate, and highly precise, with acceptable uncertainties and results, considering procedures normally followed in the processes of recovery and reinforcement related to this type of works. The results have shown that precision geometric levelling is an effective alternative, with remarkable advantages in assembling times and installation, as well as in monitoring post-recovery process of structures (medium and long term), and as the possibility of establishing a correlation between the behaviour of the monitored points. In addition, precision geometric levelling is a valid alternative to be implemented jointly with structural instrumentation techniques, especially where redundancy needs to be obtained in the observations.
This paper presents a study about the housing pricing using hedonic modelling. The pricing models have several uses, such as determinate property taxes or to mortgage decision analysis. In the case of taxation, models must be broader, aiming at the evaluation of a set of housing units. It makes the work seem more complex. This issue is a barrier to widespread statistical inference in tax assessment, especially in small and medium-sized municipalities, which have fewer human resources. This paper presents a study in two medium-sized Brazilian cities, demonstrating the process of analysis and developing models to single-family properties. Data were collected on real estate agents and valuation reports. Statistical analysis allows finding the equations that best fitted observed data. Significance tests of variables and models were performed and indicated that the models have good explanation of prices. It can be concluded that these models could be used in evaluation with tax purposes
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