At the Universidad de las Fuerzas Armadas - ESPE, in Ecuador, different structural blocks with and without seismic isolators of triple friction pendulum are being built. In one of them, the access stairs to the floors is located in a Structural Block with no seismic isolators; therefore, it has special construction details to allow a free displacement of the Isolators’ Building without impacting the Stairs’ Building at all. This paper addresses these details. On the other hand, three models (each with different degrees of freedom) for seismic analyses of a longitudinal frame and a transversal frame are shown. The results were obtained and compared using the Spectral Method and the Capacity Spectrum Method. Moreover, these results highlight the importance of appropriately selecting the numerical calculation model. Later on, the seismic analysis of the Structural Block of the Access Stairs is shown, using a three-phase constitutive model.
The present research summarizes the test results of mechanical capacity of built-up structural elements, intending to introduce the possibility of using RTPBB as material for creating structural solutions for temporary housing, and for small houses. Hollow columns and beams models helped in understanding theoretical behavior by using nonlinear stress-strain relations of the material, and finite element models (FEM) to determine the areas where stresses and deformations are principal. Optimum thickness boards of about 15mm helped to build the specimens, which afterwards were failed using and MTS testing machine, following monotonic loads. Tests performed, mainly focused on compression and bending, using hinged supports and a central two-points-loading arrangement respectively. Additionally the research presents a basic comparison of mechanical results to those reported by technical manuals of commercial plywood in Colombia. In a parallel analysis, a functional unit defined, helped in the estimation of the carbon dioxide footprint equivalent for various steps of the production processes of the base material. Results show that although the RTPBB has a low elastic behavior, stresses remain below the ultimate stress. Column failure tends to be brittle compared to that failure for the bending resistant elements. However, the presence of local buckling suggests also the means needed to improve said capacity. Failure loads are similar to those reported for commercial plywood in Colombia, however, experiencing larger deformations. The carbon footprint was determined to be reduced about 20% (production of the material used in this research), compared to commercial plywood material in Colombia.
Civil construction, nowadays has to deal with comfort and habitability requirements and raw material lack. Thus, it is desired to reuse materials. In this context, the subfloor plays an important role in providing users with comfort, being an interesting object of analysis. Thus, this study aims to design lightweight concrete slabs with ethylene vinyl acetate (EVA) aggregates for subfloors, with two grain sizes of conventional sand replaced with EVA. The experimental program is composed of four unit mixes, three of them varying the ratio between EVA coarse and natural fine aggregates, and the one with higher quantity of EVA coarse aggregates was replaced sand for EVA fine aggregates. The subfloor slabs were molded with three thickness of 3, 5 and 7 centimeters, and a set of 3cm slabs plus 1cm of conventional coating. Slabs were submitted to specific mass tests and L’nT,w mean standardized impact sound pressure level tests. Results showed a correlation between two variables, being that 7cm thickness slabs with smaller specific mass, with total aggregate replacement, presented noise intensity reductions of 17dB in comparison to 7cm slabs with natural sand and smaller content of EVA coarse aggregate; and 28dB reduction in relation to the reference.
This paper analyzes different types of failures in buildings of the cities of Portoviejo, Manta and Bahía de Caráquez during the earthquake of April 16, 2016. The evidence derived from the failures refer to existing codes and design considerations in order to reveal how modeling corresponds or not with different reinforced-concrete columns, floor slabs and rigid frame buildings without structural walls. Given the diversity of constructive solutions found in the steel-deck slabs, a 23 factorial experiment design was performed to identify the influence and independence of the type of node, the rectangularity of the floor plan and the height of buildings on the strength and deformation parameters of floor slabs, in relation to the failures observed. Additionally, this paper undertakes a singular analysis approach of different failure causes in a building demolished in the city of Portoviejo, based on evidence revealed by the earthquake, and described some of the distinctive features of this type of study.
This paper presents a methodology for predicting vibrations produced by underground railways through 2D FEM numerical models formulated in the time domain. The numerical approach is based on the application of train loads as dynamic displacements on the rail pad and the application of load correction coefficients in 2D numerical models. This load reduction coefficient is calculated by comparing 2D and 3D static numerical models, assuming that vertical displacements are equal in both cases. This methodology has been applied in a real case in Madrid, Spain, where a reasonable fit between numerical and experimental results was found. Therefore, it could be a useful tool in early stages of design and for studying mitigation measures.
Building Information Modelling (BIM) offers a wide range of tools and allows integrating all disciplines of a building project within a virtual and unique model. However, the full use of BIM requires careful planning and implementation by the firms. The objective of this study is to follow and analyze BIM implementation processes in design and building firms and relate them to the literature. We undertook a study in five firms, comparing companies that have implemented the platform and others that are currently implementing it. A partial implementation of BIM tools was found in all cases. There were some problems such as the need for changes in the equipment and the design process, which required more time and higher costs for staff training. Even so, we conclude that there was an increase in the quality of design and execution of the works, and incompatibilities between design and execution were reduced as well.
Construction work is considered to be one of the most dangerous activities, in which the workers are exposed to multiple risks. Due to the complex interdependence of the tasks and the fact that the productive plant changes location constantly, it is more difficult to manage injury prevention and safety in construction sites, with respect to other activities. The present study was conducted in Yucatan, Mexico, where low levels of prevention and compliance with obligatory norms have been reported. The aim was to analyze a sample of over one hundred construction accidents in building works in order to determine the causes and consequences of the lack of prevention. The risks which caused the accidents were analyzed with regard to their incidence and severity; the resulting injuries and the occupations of the workers affected were also analyzed. It was concluded that urgent measures are required in order to prevent four main risks (Concrete and masonry construction, Fall protection, Scaffolds, and Electrical); in addition, no actions were observed providing evidence that the phenomenon of lack of prevention in construction works is a priority for the authorities, companies or the trade unions.