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

The methodology that calculates the internal stresses on a penstock shell restrained by a rigid ring girder was developed since the 1930’s, however, its automatization has not been implemented by commercial use software due to its complexity. This projectintends to automate one methodology to calculate the internal stresses on a steel penstock shellrestrained bya ring-girder. A penstock under normal operation condition, this is apipe full of water under pressure, was analyzed. A calculating tool was produced using EXCEL 2016 and Mathcad 10, for calculating the internal stresseson the penstock’s ring girder cross sections. The tool doesn’t consider the earthquake loading conditions.

In this research it was studied the mortars for block pasting, fabricated in situ and the effects in their physical and mechanical characteristics by adding lime to the mix. For this, were made mortars type M and type S with and without lime, using the volumetric proportions that the Seismic Code of Costa Rica 2010 (CSCR 2010) says. It was used quarry sand and industrial sand like fine aggregate, separately. Testing compressive strength was conducted in mortar cubes at 7 and 28 days, also percentage of water retention, air content and workability were tested. Also, masonry prisms and “crosses” were made for compressive strength and bond test, respectively. All this, to determine if the use of lime produced in this country improves the properties of the bond masonry mortar, because this could reactivate in Costa Rica the use of lime in the Industrial construction. Tests were made with 3 different limes, and the results change depends on the lime used. But in general, the lime improves some properties like water retention, workability and bond, and in some cases increases prisms resistance. Conversely, compressive strength in mortar cubes decreases and the air content wasn’t affected.

Energy efficiency consists of achieving lower energy consumption compared to the same benefit The different amount of solar radiation that is reflected or absorbed is due to the surface color. The tiles developed in this research are black, as they have rubber particles in their composition, which contain carbon black. Dark colors have a higher solar absorptivity, therefore, the alternative of coloring the tiles with light colors was analyzed, to reduce the absorption of solar radiation. The objective is to evaluate different technical possibilities for laying tiles from the incorporation of pigments, and to determine the energy efficiency. For manufacturing, colored oxides, masterbatch, rubber and polyethylene were incorporated. Experiments were carried out varying their dosages and for the determination of the thermo-physical behavior of the tiles, optical properties (albedo and emissivity) and surface temperature of 2 sample units were tested -one tile colored in green and one in black-. The group with the best results was number 3, where black rubber, green polyethylene and masterbatch were mixed. When comparing the thermo-physical performance of recycled green tiles in relation to black tiles, a more efficient behavior was observed in green tiles. Increases in the albedo level of 11% and decreases in surface temperature greater than 8 ° C were recorded. Energy efficiency consists of achieving lower energy consumption compared to the same benefit The different amount of solar radiation that is reflected or absorbed is due to the surface color. The tiles developed in this research are black, as they have rubber particles in their composition, which contain carbon black. Dark colors have a higher solar absorptivity, therefore, the alternative of coloring the tiles with light colors was analyzed, to reduce the absorption of solar radiation. The objective is to evaluate different technical possibilities for laying tiles from the incorporation of pigments, and to determine the energy efficiency. For manufacturing, colored oxides, masterbatch, rubber and polyethylene were incorporated. Experiments were carried out varying their dosages and for the determination of the thermo-physical behavior of the tiles, optical properties (albedo and emissivity) and surface temperature of 2 sample units were tested -one tile colored in green and one in black-. The group with the best results was number 3, where black rubber, green polyethylene and masterbatch were mixed. When comparing the thermo-physical performance of recycled green tiles in relation to black tiles, a more efficient behavior was observed in green tiles. Increases in the albedo level of 11% and decreases in surface temperature greater than 8 ° C were recorded. Energy efficiency consists of achieving lower energy consumption compared to the same benefit The different amount of solar radiation that is reflected or absorbed is due to the surface color. The tiles developed in this research are black, as they have rubber particles in their composition, which contain carbon black. Dark colors have a higher solar absorptivity, therefore, the alternative of coloring the tiles with light colors was analyzed, to reduce the absorption of solar radiation. The objective is to evaluate different technical possibilities for laying tiles from the incorporation of pigments, and to determine the energy efficiency. For manufacturing, colored oxides, masterbatch, rubber and polyethylene were incorporated. Experiments were carried out varying their dosages and for the determination of the thermo-physical behavior of the tiles, optical properties (albedo and emissivity) and surface temperature of 2 sample units were tested -one tile colored in green and one in black-. The group with the best results was number 3, where black rubber, green polyethylene and masterbatch were mixed. When comparing the thermo-physical performance of recycled green tiles in relation to black tiles, a more efficient behavior was observed in green tiles. Increases in the albedo level of 11% and decreases in surface temperature greater than 8 ° C were recorded.

This article collects and identifies the addition of certain mineral additives most frequently used in the construction industry as modifiers of concrete during its fresh and hardened state, most of which are used as a partial replacement for cement. Currently researchers seek to optimize the properties of the design of mixtures depending on the use for which they are conceived, as well as that it is economically feasible and respectful with the environment. 50 articles indexed between 2010 and 2021 distributed in the following databases were reviewed: 37 articles from Scopus, 10 articles from ScienceDirect, 2 articles from Springer and 1 article from SciELO. The additives under study are granulated blast furnace slag (EAHG), fly ash (CV), silica fume (HS), rice husk ash (CCA). Most of them present a considerable improvement in their mechanical characteristics of traction, resistance to compression and modulus of elasticity. The addition of CV improves the mix of the design during its fresh state, the CCA during its hardened state and the best resistances for the HS; However, the EAHG turns out to meet almost all expectations in a higher percentage and likewise, together with the CCA, they are potentially competitive

The tower crane is an equipment with a high operating cost and critical for the advancement of vertical constructions. Therefore, the need arises to have instruments that allow controlling the performance of the tower crane in vertical construction projects. In this investigation, a dashboard was created, which makes it possible to measure and control the performance of the tower crane during the execution of the construction project. The designed tool was implemented in the construction of a building with a structural system composed of walls, columns and posttensioned slabs. Only one tower crane was studied. On some occasions, logical and reasonable causes were provided to explain a certain behavior of the analyzed tower crane. However, these causes may be neither the only ones nor the definitive ones. Work sampling was used to obtain representativeness in the samples. It is estimated that the proposed tool will bring the following improvements: focus of the tower crane on the most critical tasks; measurement and improvement of the productivity of various tasks essential for advancement; determination and reduction of the percentage of downtime; better monitoring of incidents and reduction of accidents, which reduces the time in which the project is stopped due to accidents; and, finally, greater monitoring of tower crane maintenance, which reduces the time in which the equipment is stopped due to failures. The cost of implementing the tool presented is viable for most companies in charge of vertical constructions. The cost-benefit ratio of the proposed instrument was estimated at factor of 9.8, which suggests that the benefits of the tool are considerably greater than its costs.

In this research it was studied the prefabricated system of columns and horizontal tiles with uniformly distributed loads perpendicular to the plane of the wall. For this, a wall on natural scale was built, It was made by two groups of tiles, top plate beam and concrete foundation. The load was applied with air bags to generate a uniform pressure on the wall. The most important result is the experimental verification that the columns are the critical design element in prefabricate system of columns and horizontal tiles. It was also possible to demonstrate that the resistant requirements stablished in INTE C131:2019 are adequate for support wind and earthquake pressure safely.

This article presents the development curves of compressive strength through curing time for concrete mixtures made with three types of modified cements marketed in Costa Rica, and their combination with national aggregate from sources of pit and river. The cements used for the investigation were MM/A (E-C) – 28, MM/B (P-C) – 28 and MP A – AR, defined according to regulation RTCR 479:2015 Materiales de Construcción. Cementos Hidráulicos. Especificaciones. Due to the lack of resistance development curves for concrete made with different types of modified cements and aggregates commercialized in the country, the objective of this investigation was focused on obtaining such curves and the resistance development percentage. All the material used, was characterized according to the ASTM o INTECO standards procedures; it was also verified that the aggregates and cement to be used were adequate by the parameters established in ASTM C33/C33M-18 and INTE C147:2018, respectively. Cylindrical specimens of 150 mm x 300 mm were used to determinate the compressive resistance, being failed at 3, 7, 28 and 56 days; following a mix design determined from the ACI 211-91. A statistical analysis was performed to the generated data to establish relationships and support the results obtained. With this investigation it was possible to demonstrate that the cements commercialized in Costa Rica with a degree of blast furnace slag are able to present a significant resistance gain in the concrete after the 28 days of curing, the greater compressive resistance of the concrete is generated when using river aggregate, and generally the strength of the concrete does not vary significantly when using the same type of cement for different aggregates.

Infiltration in buildings is one of the most frequent problems and, in most cases, is the product of pipe leaks, construction defects, among others. Their detection is difficult, since they do not present external manifestations in the first phases. Infrared thermography may be a potential technique for detecting these defects, since it does not need direct contact with the inspected structure and has real-time results. Thus, this article aims to evaluate infrared thermography to detect infiltrations due to accidental causes. The methodology of the work consisted in the inspection of the common areas of a multifamily condominium with a thermographic camera and the use of a humidity detector, in a complementary way. The results allowed to prove that the detection was possible with small thermal gradients, around 0.4 °C to 1.5 °C, where the affected areas were visualized with lower temperature due to the thermal inertia of the water. In the inspection for infiltration verification, the technique showed a rapid detection of this pathological manifestation and can be used as an auxiliary tool

The modulus of elasticity is a property of great importance in the structural calculation, which allows understanding the relationship between the stress and the deformation of an evaluated material, in this matter, a correct prediction of the modulus of elasticity of concrete allows the Structural Engineer design elements or structures that perform as it were conceived. In this investigation an equation to calculate the modulus of elasticity determine were determined for two mixtures of self-compacting concrete (SCC) with nominal strength of 70 MPa at the age of twenty-eight days.The only variable analyzed in this study was the type of hydraulic cement: cement modified with initial high strength limestone and modified cement with pozzolana. For fresh concrete the following testwere analyzedcomparatively: temperature (ASTM C1064), unit weight (ASTM C138), air content (ASTM C231) and unrestricted flow (ASTM C1611). For hardened concrete, the compressive strength (ASTM C39), elastic modulus, Poisson ratio and shear modulus (ASTM C469) were studied.

Building Information Modeling (BIM) is a new methodology that has been growing in recent years within Costa Rica. However, this diffusion has generated isolated attempts, mainly from the private sector. In order to the current capability of the country in the use of the BIM, some interviews were distributed among the public, private and academic sectors; which were used in conjunction with the “Adoption Point” and “Macro-Maturity Components” models developed by Billial Succar and Mohamad Kassen. This permitted to understand the starting point of a potential implementation of the BIM methodology at the national level and develop a series of tasks to implement the BIM methodology in the country. That roadmap was validated by a committee of experts who have extensive knowledge about the current situation at the national level. The product of this work is an adoption process or roadmap for the incorporation of the BIM methodology during the planning, design, construction and operation phases of public works in Costa Rica as a tool to improve the management of construction projects.