Construction and Geotechnics

The impact of the freezing-thawing process on soils, accompanied by frost heaving and changes of physico-mechanical properties and water permeability, leads to a decrease in the reliability of the designed structures such as dams, landfill caps, pavements. The existing apparatuses for the study of frost heaving are systematized according to their purpose (measured parameters), design features and experimental conditions. The authors pointed out the directions for improving laboratory equipment and presented developed innovative equipment for studying both the frost heave and its consequences. The article presents apparatuses for testing of frost-susceptible soils with the ability to manage the freezing front movement and water migration from the thawed to the freezing parts of soil. A laboratory equipment for studying the water permeability of soils along and across the ice lenses in subject to cyclic freezing and thawing is presented. Taking into account the dependence of criteria of frost-susceptibility of soils on experimental conditions, the authors propose a new approach to assessing the impact of frost heave phenomenon on designed structures. According to the approach the preparation of the laboratory research program and the analysis of their results are carried out using data obtained from numerical modeling both of the laboratory equipment and of the designed constructions.

The procedure for designing reinforcement of shallow foundations of reconstructed, restored buildings using piles (injection, bore injection, composite pressed, screw, etc.) is considered. At the first stage of the design, the constructive solution of the existing foundations, the structural diagram of the building (structure), as well as the loads transferred to the building structures before and after the reconstruction (restoration) of the building are established. An assessment of the soil conditions of the construction site of the building being reconstructed is carried out; a bearing soil layer is identified for deepening the lower ends of the piles. Based on the data obtained, the loading of the base of the foundations of the reconstructed (restored) building is assessed and the need for their strengthening (or their further operation without reinforcement) is established. In the event that strengthening of the building foundations is required, the method of transferring the additional load to the piles is chosen. After that, the bearing capacity of the piles and the design loads allowed on the piles are substantiated. The design of foundations is carried out taking into account their reinforcement with piles, as well as verification calculations of the base of reinforced foundations (combined) for the first and second groups of limiting states (for bearing capacity and deformations). In accordance with the regulatory documents, strength calculations of the main structural elements of foundations are performed, which are necessary to ensure their full-fledged operation, taking into account reinforcement. At the final stage, working documentation is developed to strengthen the foundations of the reconstructed, restored building (structure). The presented algorithm for the design of strengthening the foundations of reconstructed, restored buildings using piles allows to correctly and consistently organize the work of specialists.

Concrete is currently the main man-made structural building material. It takes on extreme loads, undergoes periodic processes of freezing and thawing, which affects its integrity and, as a result, the process of cracking is observed. A promising direction of development in improving the performance properties of concrete is the use of self-healing elastic concrete, which allows increasing the strength characteristics of the concrete structure and preventing corrosion of the reinforcing elements. The article discusses the technology for the production of self-healing concrete, indicates the necessary conditions for self-healing and defines the features of its application. Also, the calculation of production costs was made and the economic effect from the basic version of the production of self-healing concrete was calculated, the relationship between the service life and cost was determined using the correlation method. As a result of the work, it was confirmed that the new method of self-healing has the prospect of implementation and is more effective in places where the production of repair work, and regular inspection of the condition of structures, in practical terms, is impossible: underground construction, underwater construction, high-rise buildings, bridge-type transport structures. The use of self-healing concrete ensures the preservation of the bearing capacity of concrete and reinforced concrete structures, which significantly increases the service life without damage and equally helps to reduce additional material costs for maintaining the facility. The same research method revealed that bio-concrete with the use of Bacillus subtilis bacteria allows reducing the level of environmental pollution by minimizing hydrocarbon emissions during the preparation of the mixture.

The article is devoted to the justification of the relevance of the development of information modeling technologies in the construction industry. The article discusses issues related to the use of BIM technologies in domestic and foreign practice, and presents examples of objects constructed using BIM technologies. The analysis of the research subject area of information modeling, the relevance of the issue of using BIM technologies at the stage of design work and the development of estimate documentation, as well as algorithms, processes and methods for introducing information modeling into the practice of design work, it was concluded that the issue of using information technologies for optimization design work, cost management of construction investment project. The advantages and disadvantages of the developed technologies for applying BIM technologies at the current stage of the practice of developing construction projects are identified. A comparison of the traditional method of estimation documentation and the method based on the use of BIM-technologies is presented. As a result, the purpose and objectives of further research in this subject area have been formulated. Recently, the introduction of information modeling or BIM technologies (Building Information Modeling) is offered to increase the success of construction projects. Thanks to BIM-technologies, the solution to a huge number of tasks arising during the construction process is reduced. However, this technology is new in the construction industry, which leads to the emergence of a large number of contradictions associated with its implementation and application.

Ground improvement as a means for allowing the replacement of piled foundations with shallow footings is systematically being used by engineers for many decades. Some ground improvement techniques that are installed by piling rigs and include cementituous columnar rigid inclusions makes it difficult to distinguish where ground improvement ends and deep piled foundations commence. This paper assists the geotechnical engineer by reviewing the concepts of rigid inclusions, how they differ with piles, and presenting of case studies of very deep applications of rigid inclusions.