Vol 18, No 2 (2022)

The results of numerical calculations can and should be verified, but testing a complex and detailed computational model is problematic. This possibility is provided by simplified models represented by simple computational schemes that are available for qualitative analysis, and the numerical results obtained are predictable. Such calculation schemes, as a rule, describe individual calculation tasks facing designers. For example, linear stability analysis is offered by the American Institute of Steel Structures (AISC). One of these models is discussed. The model under consideration is based on a linear analysis of the stability of a cantilever rack, which can be considered as a simple model of the bearing trunk of a high-rise building. A comparison of critical loads based on nonlinear and linear analysis of the stability of the cantilever rack is carried out. It is concluded that the considered linear model makes it possible to obtain a preliminary estimate of the critical load to verify the results of computer calculations using more complex models of the general stability of the equilibrium of the bearing trunk of a high-altitude object.

The article presents a continuation of the optimization of channel and I-shaped bended closed profiles (BCP) with tubular flanges and perforated walls made of rolled sheet products of both equal and different thicknesses. Such profiles are designed for light steel thin-walled structures (LSWS), which are distinguished by improved technical and economic indicators and mass demand in industrial and civil construction, which confirms the relevance of their further development. The purpose of the study is to show that the characteristics of LSWS can be further improved by shaping profiles, combining straight and round outlines of closed and open contours in a composite section, including their perforation. Through experimental design studies, solving optimization problems and variant design of the BCP, their design sections with a maximum margin of bending strength with a minimum mass have been refined. The originality of technical solutions is confirmed by patent examination. The channel BCP has extreme weight and strength with a relative height of cutouts in the wall of 1/1.87 and a ratio of width and height dimensions of 1/4.32. When the thickness of the shelves is 2 times the wall thickness, the strength and mass of the I-shaped BCP are extreme at a relative height of cutouts of 1/1.23 and a ratio of dimensions of 1/4.17, and when the thickness of the shelves is 0.6 of the wall thickness, the strength and mass of the BCP are extreme with a cutout height of 1/1.73 and a size ratio of 1/5.22. If the thicknesses of the shelves and the wall are equal, then the strength and mass of the BCP is extreme at a cutout height of 1/1.46 and a size ratio of 1/3.17.

A class of developable surfaces contains cylindrical, conical, and tangential developable surfaces. Tangential developable surfaces are ruled surfaces of zero Gaussian curvature with cuspidal edges. They give great opportunities to architects and engineers for realization of their creative projects. Both the theoretical researches in the area of geometry of torses and strength analysis of shells and the influence of these researches on the application of torses in practice are shown. A presented research demonstrated that torses found the application in shipbuilding, aircraft construction, mechanical engineering, in architecture and building, engineering equipment and communications, in road building, in anti-erosive banks, topography, and cartography, clothing articles of light industry, in sculptural forms, and in modelling with developable surfaces. It was confirmed by the references on great number of published works on the subject, real examples from practice, and by handing in 14 illustrations of real objects.

Earthquake magnitude catalogues and peak ground acceleration (PGA) maps for Ecuador may be found in several studies, however, there are rare works on the characterisation of the epicentral macroseismic intensities associated with earthquakes. In view of the concept that macroseismic intensity enables us to categorise the extent and severity of damage to buildings and structures caused by an earthquake, this study aims to compile a macro-seismic intensity-based catalogue of earthquakes in Ecuador, characterise the epicentral macroseismic intensities associated to seismogenic sources and perform a comparison with the National Seismic Hazard Map. This paper is the first that presents a catalogue of earthquakes with macroseismic intensities ≥VII and a series of maps of earthquake epicentres according to intensity, focal depth, data and magnitude of seismic events in Ecuador, based on the study of historical and instrumental records from 1900 to 2021. The obtained data shows that 95% of the territory of Ecuador has a PGA > 0.1 g, which corresponds to seismic intensities greater than VII, while regions with seismicity>VIII (ag = 0.2 g) constitute 86%, and 3.8% of the territory of Ecuador has very high seismicity (>IX), where the PGA exceeds 0.5 g. This information suggests that the normative National Seismic Hazard Map of Ecuador underestimate the hazard mainly in the south-east and in the Central Andes of Ecuador, and require an actualization.

The construction industry is one of the important pillars of the economy. Building Information Modeling (BIM) is a set of technologies that aims to enhance collaboration across the architecture, engineering, and construction industries to improve the productivity and quality of the design, construction, and maintenance phases of a building. Rethinking construction is the key to increasing productivity. However, BIM has not been widely adopted in the construction industry. It is necessary to understand the main problems hindering the implementation of BIM, consider the appropriate strategies that can be applied to gain a deeper understanding of BIM, conduct a comprehensive and systematic analysis of the factors influencing the implementation of BIM. Based on a literature review, a questionnaire survey and the collection of statistical data, factors of a negative impact on the implementation of BIM were identified. The results show that key factors influencing BIM adoption include a lack of trained professionals, of investment in staff training, of BIM standardization, as well as the position of leadership in organizations. This article puts forward some proposals to promote the implementation of BIM and specific measures to implement the widespread use of BIM technology in the construction industry.