Building structures. Soils and foundations. Technology and organization of construction. Designing of buildings and constructions. Engineering survey and inspection of buildings
Introduction.
Large-span structures are designed as entertainment and mass-use buildings, sports facilities, etc. A steel arched structure can be used as a covering for large-span structures. The issue of the rational design of large-span steel
arches, as well as the proper choice of the structural design and the analysis of its bearing capacity is relevant.
Materials and methods.
The covering of a tennis sports facility with the span of 108 m, that represents a double-hinged steel arch without tightening, arches with prestressed tightening and several lattice options are considered. The cross-section of structural elements was selected; the effect of prestressing on forces and displacements in the arch, as well as the amount of metal per structure were analyzed. The general stability of these arched structures was analyzed. Calculations were performed in the geometrically nonlinear formulation using the LIRA-SAPR software package.
Results.
It is determined that the weight of the arch, including the tightening and the lattice is smaller than the weight of the arch without the tightening. The amount of metal, used to make columns, can be reduced to simplify structural units due to the absence of gusset transfer from the arch with tightening to columns. The required prestressing value is set for the tightening to ensure the required rigidity of the arch. Several methods were used to determine the critical load at which the arch loses its stability in its plane: the analytical method, geometrically nonlinear calculation results, and the Stability mode implemented in LIRA-SAPR software package were employed. The critical load turned out to be higher for the arch with tightening.
Conclusions.
Following the above computations, a decision was made to use a double-hinged arch with prestressed tightening and a lattice as the covering of the sports facility. The values of the critical load that triggers the arch stability loss, obtained using the geometrical nonlinear finite-element analysis and the Stability mode, were quite close. Application of the analytical method resulted in an overestimated value of the critical load, which prevents it from being recommended for use.
Introduction.
Underground space development in the course of infill construction in confined spaces of megalopolises is a promising development trend in construction. To save the workspace, the “top-down” approach can be used. In this case, a substantial portion of the underground work consists in the soil development and loosening under the protection of beams, which is relevant for frozen soils in Central Russia. The analysis of regulatory documents and the studies, conducted in this area, has proven that there are no methodological recommendations on the arrangement of soil excavation in confined spaces. The purpose of the study is to analyze and systematize current methods of soil development and loosening and to evaluate their applicability in confined spaces.
Materials and methods.
The authors consider widely used excavation techniques (mechanical, hydro-mechanical, and explosive ones) and less widely spread soil development methods (electric pulse and thermal ones). The expediency of excavation mini-technologies, designed for works in confined spaces, is emphasized. Attachable hydraulic and electromagnetic machinery, used to loosen soils, is analyzed. The analysis of these methods shows their strengths and weaknesses, as well as the applicability of the “top-down” technique.
Results.
Combinations of machines designated for soil excavation and loosening within the framework of the “top-down” technique are made to further estimate the engineering and economic performance and their comparative analysis. The authors propose combinations of excavating machines that represent lightweight or mini-items having mounted soil loosening and excavation mini-machines.
Conclusions.
The practical value of the study consists in the analysis of available methods of soil excavation and loosening and the assessment of their applicability to the confined conditions of construction of substructures of buildings using the top-down technology, which is relevant for Central Russia. The authors made combinations of machines whose operation is mostly based on mechanical methods. The authors suggest considering the use of mini-machines and attachments.
Architecture. Reconstruction. Restoration. Creative concepts of architectural activity. Architectural design. Urban development. Urban management
Introduction.
Local nature, the climate, the sea, and the mountainous terrain influence the development of the built-up environment in Novorossiysk. These factors make a large contribution to the microclimate index of the urban atmosphere, and they must be taken account in the course of urban planning and architectural designing.
Materials and methods.
Advanced weather models, used in applied meteorology, such as ICON, GFS and GEM, which take into account the climatic features of the Black Sea coast, and unique whole-year wind patterns, typical for the area, were used in this scientific research.
Results.
The authors suggested introducing climate-based city zoning into the urban planning practice of Novorossiysk. In particular, the residential area on the west coast of the Tsemesskaya Bay along the Black Sea coast can be divided into the two main parts: the development area, whose mission is to protect urban spaces from strong winds, reaching high velocities in the winter season, and the development zone that triggers moderate breezes in the warm season. Principal urban planning and architectural design recommendations were developed for both territories.
Conclusions.
Climate-based city zoning, if introduced into practical urban planning, will substantially improve the microclimate indices of development areas in the summer time by facilitating favourable breezes and limiting access for extremely cold winds, blowing from the north-east in winter, if the architectural, structural and space planning recommendations are implemented.
Introduction.
Cultural heritage: monuments, ensembles, buildings and structures, archaeological sites define the urban identity of a settlement, reflect the historical development path of the people and are one of the main priorities in urban development. Urban risks are considered as the possibility of something happening that has a negative impact on the sites, as well as any possible loss that affects the value of cultural heritage, which can be divided into several categories.
Materials and methods.
From the point of view of the Sets Theory, the description of changes in the totality of tangible and intangible cultural heritage, occurring as a result of natural and anthropogenic factors, which allows to determine the main risks of its loss, has been proposed. The suggested mathematical model serves as the basis for the development of information tools for identification, assessment and consideration of historical and cultural heritage in urban planning.
Results.
Based on a retrospective analysis of the historical development of Homs, a classification of cultural heritage sites has been proposed, and a diagram of the transformation of the collectivity of objects of tangible and intangible cultural heritage as a result of natural and human factors of the risk of their loss has been created.
Conclusions.
It was found that the highest risks of loss of immovable objects of cultural heritage include natural catastrophic processes and phenomena (earthquakes), and military conflicts. As a result of which, in particular in the city of Homs, a new local architectural style “Homsi” was formed to replace the Byzantine culture.
Building materials and products. Technologies for building materials production. Nanomaterials and nanotechnologies
Introduction.
The purpose of this work is to study the thermally modified peat additive, the use of which is scientifically justified in the works of professor N.O. Kopanitsa and her colleagues. This additive is extracted from the raw materials from the Kaliningrad region, and the authors focus on its effect on the consistency, moisture-retaining capacity of the mix, and the strength characteristics of fine-grained concrete.
Materials and methods.
The additive was made from lowland peat extracted from the Glushkovo quarry in the Kaliningrad region. Raw materials were subjected to thermal treatment with limited access of oxygen.
Results.
The authors have proven an increase in the consistency and water-retaining capacity of mixes that have 4 and 8 % additive. On the 21 day, an 9 % increase in the flexural strength of concrete specimens with the 4 and 8 % additive was registered in comparison with the benchmark specimen (5.5 MPa for the benchmark mix and 6 MPa for the 4 and 8 % additive); an increase in compression strength reached 23 % when the 8 % additive was used (40.7 and 50.2 MPa for the benchmark mix and the one that contains the 8 % additive, respectively).
Conclusions.
The presented results of the research show a strong potential for the improvement of physical-mechanical properties of concretes by using thermally modified peat additives made from the local raw materials extracted in the Kaliningrad region.
Engineering systems. Exploitation of buildings. Problems of Housing and Communal Complex. Energy efficiency and energy saving. Safety of buildings and structures. Ecology
Introduction.
The issue of revising the existing regulatory documents at the stage of operation of residential buildings becomes relevant due to the need to take into account scientific and technological achievements in the field of standardization. The emergence of new building materials, technological methods of manufacturing structures, methods of performing repair and construction work leads to the need for an ongoing update of the regulatory framework of construction. The object of the study is a set of regulatory documents focused on the stage of operation of construction facilities. The purpose of the work is to prepare proposals for updating, correcting and supplementing the regulatory framework governing the stage of operation of construction facilities.
Materials and methods.
The task of this work is to analyze the domestic regulatory framework affecting the concept of operation of construction facilities, to make a classification of requirements for capital construction facilities at this stage and to structure regulatory technical documents.
Results.
Proposals were developed to adjust, supplement and update the regulatory framework of the operation stage.
Conclusions.
Within the framework of this study, regulatory technical and methodological documents affecting the concept of the stage of operation of buildings and structures are systematized and analyzed; a list of regulatory documents requiring adjustments and additions is made.
Introduction.
The ability of runoff modeling is an essential step in the hydrologic modeling process and therefore water balance studies, therefore, this study aims to verify the ability and reliability of the MIKE 11NAM program in modeling runoff, in the upper basin of Orontes River in Syria, with the use of artificial intelligence models to fill the gaps in runoff time series.
Materials and methods.
In this study, models of artificial neural networks and fuzzy inference models were used and they were compared with each other to determine the best model in order to fill the gaps in the surface runoff data at Al-Jawadiyah and Al-Amiri stations. Then the results were used in the modeling process using the MIKE 11 NAM program.
Results.
The results showed a high reliability of artificial intelligence models, whether neural networks or fuzzy inference models, with a relative preference for neural networks, and after using these results within the data required for modeling in the Mike program, it was found that there are large differences between the observed and simulated values due to the lack of existing data on the study area.
Conclusions.
This study recommends to continue research on the issue of hydrological modeling in case of lack of data and to compare between different models to find the best way to solve this problem.