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A 19-story reinforced concrete building, two underground stories and one mechanical floor, located in Santiago, suffered significant damage during the earthquake in Chile on February 27, 2010, highlighting the failure of a wall in the first underground story, which spread through the section, with significant loss of concrete and buckling of the longitudinal reinforcement in edge and web. In the present work it has been tried to obtain an explanation of the damage and to evaluate the possibility of predicting said damage from the results of linear dynamic time history analysis of a 3D building model, considering the three components of the seismic record. It was observed that a linear elastic model, under certain conditions, is capable of determining the most probable damage location, initiated by activation of a vibration mode associated with a large translational mass, determined by energy pulse arrival at a specific time from the seismic signal (obtained by spectrograms) and whose frequency is similar to one of the fundamental vibration building modes. The criteria that the model must meet in order to approximately reproduce the location of the damage are evaluated, and certain normative aspects of the design are analyzed. [ABSTRACT FROM AUTHOR]

Landslides, caused by slope instability, are a recurring problem on the Alóag-Santo Domingo road in Ecuador, causing significant human and material losses. This study reviews slope stabilization techniques using false tunnels, focusing on their effectiveness in mitigating landslides on this road. The main objective is to analyze the effectiveness of false tunnels in slope stabilization and landslide protection. Detailed geotechnical studies were analyzed, including geophysical prospecting using seismic refraction and electrical resistivity. The data obtained were analyzed with specialized software (SLIDE v 6.0 and Phase by Rocscience) to evaluate the stability of the slopes and design the necessary stabilization measures. The methodologies included the MMST method, full-face excavation with deformation control support, and the use of steel fiberreinforced concrete (SFRC). Geotechnical studies identified critical materials such as sandy silts, colluvium, and volcanic rocks. The implementation of false tunnels, using advanced methodologies, significantly improved the stability and safety of the slopes. These techniques proved effective in managing large deformations and ensuring the integrity of the road infrastructure. The implementation of false tunnels on the Alóag-Santo Domingo road has proven to be a robust and efficient solution for slope stabilization. [ABSTRACT FROM AUTHOR]

The types of methodologies to be able to assign or calculate the pre-sizing of a certain structure allow us to know the behaviors of the structural elements throughout their useful life, which can be observed and analyzed when the static and dynamic seismic analysis of the building is carried out. In order to pre-size a building, the number of floor levels, the span width between beams and columns, and the calculation of the load metering for each structural element must be taken into consideration. The main objective of this research is to be able to analyze the effects that occur in the pre-sizing of the vertical structural elements (columns) in terms of the drifts of a 6-story building without a basement under the parameters of the Peruvian E-Loads Regulations. 020, Earthquake Resistant Design E. 030 and Reinforced Concrete E. 060. The final results will demonstrate that method used was appropriate for the design of the building and this will influence the costs of its construction. For the investigation, it is concluded that the seismic method is the most appropriate methodology for calculating the pre-sizing of structural elements. [ABSTRACT FROM AUTHOR]

Prefabricated foundations are manufactured off-site and transported for on-site installation. This type of foundation is an option to consider in new projects because its fabrication and transportation can be faster and less expensive than the construction of a traditional foundation on site. In Chile, precast reinforced concrete elements are generally used in road infrastructures such as bridges and highways. While precast foundations can be an attractive option due to their speed, it is important to keep in mind that they must be carefully designed, manufactured and installed to ensure that they are solid and safe. On the other hand, it is important to evaluate the impact of this construction method on project schedules and costs in order to contribute to the modernization of the construction process. [ABSTRACT FROM AUTHOR]

Compliance with the "strong column - weak beam" criterion in the structural design of buildings ensures better behaviour of structures in seismic events. Design standards recommend an over-resistance factor of between 1.2 and 1.4. The consideration of the Dynamic Soil-Structure Interaction DSI in the analysis modifies the collapse mechanism, so researchers recommend factors higher than 2. In the present research a nonlinear static analysis (pushover) is developed, using ETABS V19 software, of a 12-story reinforced concrete building with mixed typology, in which stiffness ratio values of 1.4, 2, 3 and 4 are used, and the influence of this parameter on the structural response of the building is determined. The IDSE is considered in the analysis using Sargsian's formulations. It is concluded that the increase of the stiffness ratio influences the collapse mechanism of the structures. [ABSTRACT FROM AUTHOR]

This paper presents an experimental study on the compressive strength of concrete cylinders reinforced with expanded metal meshes. The investigation aims at comparing the compressive strength of concrete specimens strengthened with expanded metal meshes with different orientations. A series of compression tests were performed to obtain the structural performance on jacketed specimens, and then compare these with the unreinforced concrete cylinders. Expanded metal tubes were fabricated using circular geometries with two cell orientations. The results showed that cell orientation enhance the compressive strength of the specimens. [ABSTRACT FROM AUTHOR]

This study aimed to determine the area of reinforcing steel in rectangular reinforced concrete beams, a critical concern given that a significant proportion of residential structures in Peru do not conform to technical design regulations. Data were collected through a structured form encompassing various design variables, yielding a comprehensive data matrix. The methodology adopted involved Knowledge Discovery in Databases (KDD), executed in several stages: (1) selection, where the InfoGainAttributeEval algorithm was utilized to identify variables influencing the reinforcing steel area; (2) preprocessing, during which anomalous and duplicate data were purged using the Python libraries, Pandas and Numpy; (3) reduction, and (4) data mining. For the latter, Decision Stump, Hoeffding Tree, J48, Logistic Model Trees (LMT), and Random Tree classification algorithms were employed, facilitated by Weka 3.9.4. Accuracy rates of these algorithms were found to be 25, 51.70, 77.97, 78.39, and 88.98% respectively. The Random Tree algorithm, in conjunction with the GP_04 model, provided estimations of the steel area in the beams with a reliability exceeding 88%. The application of this model could enable the optimization of beam design, facilitate cost savings on materials, and enhance structural safety. This research thus presents a significant contribution to the field of structural engineering, particularly in regions where compliance with technical design standards is suboptimal. [ABSTRACT FROM AUTHOR]

The main objective of this research was to evaluate the behavior of composite sections of different configurations subjected to bending, considering the parameters established by ANSI/AISC, NSR-10, ACI-18 and laboratory tests such as the four-point bending test. Theoretical studies were used to evaluate the stiffness, strength and stresses of the sections in order to categorize and compare them with reinforced concrete sections and structural steel sections. Laboratory tests verified the effectiveness of the theoretical calculation and the real behavior of the materials. The test results showed a close theoretical validation and a ductile and favorable bending behavior due to the isolation of the compressed and tensioned parts. [ABSTRACT FROM AUTHOR]

Copyright of Crítica y Resistencias: Revista de conflictos sociales latinoamericanos is the property of Fundacion El llano - Centro de Estudios Politicos y Sociales de America Latina (CEPSAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of DYNA - Ingeniería e Industria is the property of Publicaciones Dyna SL and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The social perspective is a crucial aspect of constructing sustainable infrastructures. This study assesses the social life cycle analysis of an economically optimized precast reinforced concrete articulated frame. The manufacturing stage is identified as the most influential in the structure's social impact by analyzing the phased contribution to the overall social damage. Furthermore, it is confirmed that the modular structure exhibits notably minimal impact during the construction and end-of-life stages. The analysis of the most significant materials and processes indicates that passive reinforcing steel is primarily responsible for the social damage of the structure. While the contribution of concrete and transportation is comparatively lower, it remains relevant across the four categories of damage examined. These findings underscore the significance of considering social aspects in transportation infrastructure development and offer valuable insights for decision-makers and stakeholders. [ABSTRACT FROM AUTHOR]

The article presents a study on the durability performance of concrete in the coastal area of Manabí, Ecuador. The problem of premature deterioration of reinforced concrete structures due to atmospheric corrosion of the reinforcement steel is highlighted. The study focuses on the coastal city of Bahía de Caráquez, where many reinforced concrete structures have deteriorated due to atmospheric corrosion. The objective of the study is to establish durability requirements that guarantee a prolonged service life in reinforced concrete structures exposed to the aggressive coastal environment. The results of the study could contribute to construction regulations in Ecuador and reduce the costs of repairing structures. [Extracted from the article]

Copyright of Revista: Módulo Arquitectura CUC is the property of Corporacion Universidad de la Costa, CUC and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista de Arquitectura (1657-0308) is the property of Universidad Catolica de Columbia, Facultad de Arquitectura and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article presents an analysis of the physical-mechanical characterization of a fiber-reinforced geopolymeric concrete, whose HCV matrix is made up of 90% fly ash (CV) and 10% ordinary portland cement (OPC), using as an alkaline activator a solution composed of silicate and sodium hydroxide (NaOH, Na2SiO3) and water. The reinforcement used was SikaFiber Xorex steel fibers incorporated into the matrix in proportions of 50 and 75 kg/m3. The HCV-50 mix reported a compressive strength of 26.77 MPa at 28 days of curing, classifying it as structural concrete according to NSR-10. At the same curing age, indirect tensile strength of 3.49 MPa, modulus of elasticity of 29.32 GPa, flexural strength of 5.15 MPa and toughness up to cracking deflection (δf) of 1971,9 N.mm were obtained. This mixture, considered optimal, was used in the manufacture of concrete slabs, which presented a rupture deflection δf of 4.45 mm, ultimate deflection of 16.15 mm, maximum load supported 15.6 kN, tenacity of 49464, 8 N.mm up to δf and 145847.3 N.mm up to 3 times δf. The fiber-reinforced geopolymeric material is also proposed to be used in the production of shotcrete (Shotcrete), and in the construction of lightweight tiles. [ABSTRACT FROM AUTHOR]

Copyright of TST - Transportes, Servicios y Telecomunicaciones is the property of Asociacion Iberica de Historia Ferroviaria and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Reinforced concrete precast hinged frames are commonly used in transportation infrastructure. Advances in optimization techniques lead to improvements in the traditional structural design process. These allow for minimizing factors such as the final cost of the structure. The present study developed the economic optimization of a reinforced concrete precast hinged frame. In order to do so, the hybrid metaheuristic technique of simulated annealing with a mutation operator was applied. The algorithm parameters were tuned by means of a factorial Design of Experiments. This allowed the algorithm to show excellent performance. Once tuned, the hybrid metaheuristic was applied, achieving designs with reduced final costs. Finally, a series of main characteristics are mentioned. The designs present reduced depths and considerably dense passive reinforcement designs. The results obtained position the precast structure as a particularly interesting alternative to similar cast in place structures. [ABSTRACT FROM AUTHOR]

Shear Link Bozzo (SLB) dissipators act in the nonlinear range in order to generate a deformation in the device, preventing structural damage in buildings, for this reason, it is important to perform a nonlinear time-history analysis with at least three events seismic representative of Ecuador, and thus obtain the fundamental characteristics of each structure, knowing the seismic behavior of the devices in the country. That is why, in the present study, a non-linear time-history comparative analysis was carried out using SLB energy dissipators compared to traditional construction methods, both in reinforced concrete and in metallic structures, in order to determine which system presents a better behavior. with these devices. In this way, two buildings with different architectural characteristics were modeled, which generated a total of eight structures; four of them in reinforced concrete and four in metallic structure, of which two corresponded to structure with traditional method and two with the implementation of dissipators. The results that were generated in both construction systems show that SLB energy dissipators reduce these fundamental characteristics, mainly the maximum floor shear, where the reduction was greater than 75% in both cases. [ABSTRACT FROM AUTHOR]

In this paper, the structural seismic performance is evaluated by nonlinear analysis according to the ASCE/SEI 41-17 methodology, and the probability of collapse of structures subjected to 11 ground movements, scaled to hazard levels corresponding to serviceability, design, and maximum considered earthquakes, is determined. Three-dimensional Finite Element Models (FEM) of one, two, and threestory frame structures are evaluated subject to eleven different ground motions, selected and scaled to represent these hazard levels. Following the methodology mentioned earlier, collapse probabilities are estimated for RC frames typical of Ecuador. Structures in this study are divided into two categories: Those designed according to seismic-resistant engineering practice and those built without engineering design. For each category, infilled and non-infilled frames are distinguished. Infill masonry negatively impacts structural performance and the collapse probability of frame structures. Damages observed during previous earthquakes are consistent with the results of this study. [ABSTRACT FROM AUTHOR]

It's appropriate mechanical behavior and its low carbon footprint allow bamboo to replace conventional construction materials in various applications. Currently, it should be considered that there are countries that still do not have sufficient knowledge about the structural characteristics of locally grown bamboos. In this sense, this research presents the results for the determination of the geometric properties and the compressive and tensile mechanical properties parallel to the fiber of the species Phyllostachys aurea from the Ecuadorian Amazon. With the samples tested, the compressive strength parallel to the fiber presented a minimum standard deviation in the results, showing an average strength of 52.4 MPa. After a statistical analysis of these values, a normal distribution was observed between them, increasing their reliability; the tensile strength parallel to the fiber showed a high standard deviation in the results, due to the difficulty in preparing the required sample as established in the standard ISO/FDIS - 22157 (2019). However, the average resistance of this parameter was 90.2 MPa, confirming that it is a bamboo with great potential against this type of load. Therefore, a comparison was made between the compressive and tensile strength of the Phyllostachys aurea species with other conventional materials used in construction such as reinforced concrete, structural steel and Guadua angustifolia Kunth bamboo. [ABSTRACT FROM AUTHOR]

The objective here is to determine the influence of the incorporation of recycled rubber in structural concrete and its hypothetical seismic response, developing the investigation under a type of applied investigation, of pure experimental design with a non-probabilistic sample of DBCA method of 84 briquettes that include the standard concrete with a design of 210 kgf/cm2 and concrete with the incorporation of recycled rubber at 2%, 4% and 6%, which were evaluated at 7, 14 and 28 days of age under the technique From direct observation, parameters such as resistance to compression and indirect diametral traction where the results showed that the most optimal incorporation was 4% of both fine and granulated rubber at 28 days in all parameters, surpassing the resistance to compression by 3.76% and 4.14%, as well as the diametral indirect tensile strength by 8.98% and 16.05% with respect to the standard concrete and according to or with the analysis of the hypothetical seismic response with the optimal rubber percentages found, an improvement percentage was determined with the incorporation of 4% rubber, both fine and granulated, in the maximum drifts for the X-X direction 3.44% and 3.87%, as well same for the Y-Y direction of 3.47% and 3.96% respectively compared to the concrete pattern. Thus demonstrating that the use of 4% rubber, both fine and granulated, in concrete is acceptable. [ABSTRACT FROM AUTHOR]

Copyright of Ciencia e Ingenieria Neogranadina is the property of Ciencia e Ingenieria Neogranadina and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista: Módulo Arquitectura CUC is the property of Corporacion Universidad de la Costa, CUC and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of ESTOA: Revista de la Facultad de Arquitectura y Urbanismo de la Universidad de Cuenca is the property of ESTOA Revista de la Facultad de Arquitectura y Urbanismo de la Universidad de Cuenca and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of ESTOA: Revista de la Facultad de Arquitectura y Urbanismo de la Universidad de Cuenca is the property of ESTOA Revista de la Facultad de Arquitectura y Urbanismo de la Universidad de Cuenca and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Técnica Industrial: Revista Cuatrimestral de Ingeniería, Industria e Innovación is the property of Fundacion Tecnica Industrial and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A practical case of deep foundation for an industrial plant in Puerto Natales is presented using precast reinforced concrete piles, driven into soft clays (Nspt < 5 blows/ft). Equipment and methods were used for the evaluation of the pile structural integrity and their geotechnical capacity by means of PDA monitoring (Pile Driving Analyzer) during driving. With the results of the PDA test, together with the CAPWAP computational tool, the design hypotheses were verified. During the execution of the project, it was possible to achieve the optimization of the embedment depth and the variation of the number of piles required. [ABSTRACT FROM AUTHOR]

Nowadays, construction is one of the activities with the greatest impact, the reason why it is necessary to look for materials that contribute favorably to the environment. With this premise, this article studies the implementation of recycled tire rubber as elastomeric support in simply supported beams. For this purpose, three physical models of reinforced concrete bridges with different bearing types were developed: 1) without bearings, 2) neoprene bearings, and 3) recycled rubber bearings, which were subjected to a horizontal vibration test. Subsequently, there was a development of numerical models equivalent to physical tests, and it was determined the influence of the use of recycled rubber bearings on the mechanical behavior of the structural elements. The results indicate that the implementation of recycled rubber sheets as bearings elements produces a reduction in the internal forces of the structural elements and show an increase in the displacement of the models. The obtained results allow us to conclude that recycled rubber sheets could be used in the construction of bearings for bridge structures. [ABSTRACT FROM AUTHOR]

At present, the interest of using waste materials and byproducts from concrete has increased, due to the need for minimizing pollution on our planet. The present document aims to systematically review the literature regarding the implementation of steel residues in the concrete mix, and how this influences its physical-mechanical behavior. It has focused mainly on steel residues in the form of slag, filings, shavings, and fibers; incorporated in all types of structural concrete, used in columns, beams, footings, slabs, and walls. The use of these materials has a high impact because it helps reduce the cost of manufacturing cement and concrete, and also provides numerous ecological benefits, such as reducing the cost of landfills, saving energy, and protecting the environment from possible contamination. The indexed articles were searched in the following databases: ASCE, EBSCO, Google Scholar, ScienceDirect, Scopus y SpringerOpen, finally selecting a total of 60 articles published since 2014. [ABSTRACT FROM AUTHOR]

Copyright of Liño: Revista Annual de Historia del Arte is the property of Universidad de Oviedo, Servicio de Publicaciones and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Review of Béton, arme de construction massive du capitalisme, by Anselm Jappe, published in 2020. [ABSTRACT FROM AUTHOR]

Copyright of CULCyT: Cultura Científica y Tecnológica is the property of Cultura Cientifica y Tecnologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Many of the existing deposits in Cuba exceed their years of useful life and show a high degree of deterioration mainly due to the cracking and corrosion of the steel reinforcement. Several solutions have been given over the years to prevent corrosion, but none have solved the problem, concluding that the ideal is to replace steel with a non-corrosive material such as fiber reinforced polymers (FRP). This paper proposes the design of the walls of two case studies, using FRP bars as concrete reinforcement. The results show that even when the design requires a greater amount of FRP bars than in a similar design with steel, to cracking control, the use of these bars is a feasible solution in terms of durability and useful life of the structure. [ABSTRACT FROM AUTHOR]

The use of the Colombian seismic design and construction code requires the selection of an energy dissipation capacity (EDC) for the building that depends on the structural type and the seismic hazard at the site. This work investigates the effects on the materials quantities and the seismic behavior of reinforced concrete buildings due to the selection of an EDC superior to the minimum required for low and intermediate seismic regions. Twenty regular buildings with variations in bay lengths and height were designed according to the parameters and requirements for each EDC. Pushover analyses were performed to assess the potential seismic damage in a subset of those buildings. The results showed that the lowest amount of reinforcement in both seismic regions is obtained by selecting a moderate CDE, and that higher levels of seismic damage could occur when a CDE superior to the minimum is selected. [ABSTRACT FROM AUTHOR]

Copyright of Cuadernos de Vivienda y Urbanismo is the property of Pontificia Universidad Javeriana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Dearq is the property of Universidad de los Andes and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Loggia, Arquitectura & Restauración is the property of Universidad Politecnica de Valencia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper presents an application of the direct displacement-based design (DDBD) to a reinforced concrete frame-wall system (structures that utilize both frames and walls to resist earthquake actions in parallel). Firstly, the mathematical model is presented alongside a description of the methodology applied to determine the design displacement profile and strength proportion between walls and frames. Knowledge of the displacement profile and some recommendations for the combination of frame and wall damping components enables representation of the structure as an equivalent single-degree of freedom (SDOF) system. Secondly, the DDBD method is used to analyze and design a 12-storey building in which the displacements, storeydrifts, base shears, as well as the wall and frame strengths are determined. Then, some guidelines are presented to design the reinforced concrete structures, specifically those related to the stiffness used for the strength distribution and capacity design. Finally, a nonlinear time-history analysis is implemented in RUAUMOKO 2D, using three records from the Maule earthquake which are consistent with the displacement spectrum contained in the Chilean seismic code requirements (Supreme Decree N° 61). These analyzes demonstrate that the DDBD method provides a robust estimation of the displacement demands expected during a seismic event. [ABSTRACT FROM AUTHOR]

Copyright of Opuntia Brava is the property of Universidad de Ciencias Pedagogicas de Las Tunas, Centro de Documentacion e Informacion Pedagogica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With the purpose of using recycled glass in concrete mixtures as a partial substitute for sand and cement in Cuba, researches are carried out. This article shows the result at a laboratory scale in substituting fine aggregate and cement with ground glass in dosages of 25%, 50% and 100% for the first one and 10%, 20% and 30% for the second one. The mixtures obtained were compared to a standard for consistency and compressive strength. In the fresh mixes, a directly proportional increase in consistency was obtained with the percentage of replacement of the sand but it was different for cement, however all of them maintained a consistency suitable for use. Compressive strength gradually increased in an interval from 7 to 28 days of mixing's age obtaining values exceeding the standard sample in M1, M4 and M5 samples. The results support at a laboratory scale, the feasibility of replacing 25% of the sand and up to 20% of cement with ground glass, without affecting the standard compressive strength (25-35 MPa) for traditional concrete. [ABSTRACT FROM AUTHOR]

This work aims to obtain a simple expression, which allows defining a minimum thickness for reinforced concrete slender walls in order to avoid buckling. This expression was obtained based on the thin plates theory, with a linear-elastic analysis, considering an energetic approach and the Ritz method. The proposed model takes account for only the compressed zone of the wall, with an axial load distribution obtained from the flexocompression demands, in other words, the compression stresses in the concrete along the distance between the extreme fiber in compression and the neutral axis. The results obtained present an adequate qualitative agreement with the experimental observations, however, quantitatively the results are non-conservative. [ABSTRACT FROM AUTHOR]

Copyright of Tecnología y Ciencias del Agua is the property of Instituto Mexicano de Tecnologia del Agua (IMTA) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Introduction: The design of spread footings over a lime-treated soil is studied as an important topic in geotechnical and environmental engineering. With the emergence and use of algorithms, it is possible to solve optimization problems in engineering, leading, for example, to decreased amounts of materials, time, energy, and work. Objective: This research aims to optimize the CO2 emission and cost of building spread footings over a treated soil with hydrated lime using the modified simulated annealing algorithm (MSAA). Method: The parameters for shear strength (cohesion and friction angle) was calculated of a silty soil of the Guabirotuba geological formation of Curitiba (Brazil) stabilized with different lime contents (3, 5, 7 and 9%) at different curing times (30, 90, and 180 days). Then with these parameters, the geometry of the spread footings was optimized with MSAA minimizing the cost and CO2 emissions of their construction. For the design constraint of the structures the ultimate bearing capacity of the soil was used as criteria, the settlements produced by the service load, and the base safety factor Results: The results show that most of the problems converge to the same solution for costs and CO2 emissions without depending on curing time and lime content used, due to the solutions being restricted primarily by the maximum permissible settlements. Conclusions: With the increase in lime content, the cohesion of the mixtures increased for all curing times studied ant the friction angle had no major variations in relation to the amount of lime administered or to the curing time employed. Costs and carbon dioxide emissions for spread footing construction converge to the same results. In this sense, 9% lime can be avoided, and small percentages of lime (i.e. 3-5%) are appropriated to ground improvement and reduce the costs of this procedure. On the other hand, the MSAA can be designated as a robust algorithm due to having achieved almost equal results and, in some cases, better results compared with other algorithms to solve problems reported in the literature. [ABSTRACT FROM AUTHOR]

Introduction: In this article, an analysis of the evolution of the mechanical damage of steel fiber reinforced concrete (SFRC) and propagated ultrasonic pulse velocity (UPV) is performed; in order to correlate the UPV and mechanical damage in concrete elements with different dosages of steel fibers. For which 45 concrete samples were manufactured, with dosages of 0 kg/m3; 25 kg/m3 and 70 kg/m3, and average compressive strengths [1] of 57 MPa, 53 MPa and 44 MPa and flexural strength [2] of 5.49 MPa, 7.20 MPa and 9.60 MPa, is to clarifying that in the tested elements load, deflection and ultrasonic pulse velocity were measured in simultaneously; obtaining parameters that allowed to generate predictive equations of the damage, on a scale of 0 to 1, taking into account that a mechanical damage is advanced when an element has a high cracking and therefore its mechanical resistance capacity will be reduced (when the value is close or equal to 1) [3]; Additionally, with the completion of the project, it is demonstrated that the inclusion of steel fibers causes ductile behavior in the concrete with an increase in mechanical strength to flexion and fatigue. Concluding that it is possible to predict the mechanical damage of concrete by applying indirect measurement techniques, which will help the pathological evaluation of elements, as well as demonstrating the usefulness of using steel fibers in concrete to improve its mechanical properties. Objective: Estimate the evolution of the mechanical damage of the SFRC-type concrete, by measuring the ultrasonic pulse velocity, correlating with the flexural strength, obtaining damage prediction equations and graphs of mechanical behavior. Method: For the realization of the project an experimental model is applied; starting with a primary search for information on fiberreinforced concretes and indirect inspection methods, then the concrete mixtures that are to be made were defined and the manufacturing of the test elements was carried out; then the experimental tests are carried out and the results are analyzed; finally, to realize conclusion of the research. Results: Predictive and graphical equations of mechanical behavior are obtained, which will allow an insight of the mechanical damage of the concrete to be inspected in the first instance, which would allow establishing the physical state in the that an element made of this material is found. Conclusions: As mechanical damage occurs in a concrete element, these will increase its cracking and therefore its density will decrease; This feature can be measured with the pulse rate propagated; consequently the prediction of the integrality of the physical state in which an element is found will be predictable, allowing to know if a particular structure is at risk of collapse or close to it; The foregoing becomes more important in structures subjected to flexion (property in which the concrete offers low resistance, with respect to compressive strength), such as a bridge, a vehicular track or beams of a building. With the equations set forth, it is shown that in a mechanical damage of less than 0.5, the structure cracks, but will not collapse, but if the damage is greater than 0.5 the structure is so fissured that it will not be able to withstand the load maximum design and therefore can collapse. In the same way, the project shows that steel fibers increase the flexural strength and toughness of the concrete by at least 30%, which implies its usefulness for the construction of elements described above. This research is a first statement and will allow expanding the possibilities of indirect inspection methodologies in the field of structural study in Civil Engineering, as well as the use of steel fibers as additions, which improve the mechanical properties of concrete. [ABSTRACT FROM AUTHOR]