Vol 10, No 4 (2020)

The problem of determining the moment of formation of normal cracks in bending reinforced concrete elements with a complex cross-sectional shape, clamped at one end in brickwork and operating under the action of a negative bending moment is considered. A technique for testing prototypes of hollow-core slabs without formwork is presented. The purpose of the experiment is to determine the angles of rotation of the support nodes of hollow-core slabs without formwork, embedded in brickwork. The design of an installation for testing experimental specimens until the moment of cracking is presented. A diagram of the arrangement of measuring instruments is given to determine the deformation of the support unit at the place where the slab is embedded in the masonry, the defl ection of the prototype at the place of load application, the deformation of the brickwork simulating the wall of a multi-storey building.

The article examines the features of the calculation of large-span structures for covering religious buildings using the example of covering the middle part and the refectory of the church in honor of the holy unmercenaries Kosma and Domian of Asi, located in the village of Sezzhee, Bogatovsky district, Samara region. At the time of the work, the facility was undergoing a largescale reconstruction. Based on the data of the detailed examination of the technical condition of the building structures of the church roofi ng, calculations were made in a physically nonlinear sett ing, allowing to fully assess the stress-strain state of the monolithic reinforced concrete structure of the cover of the middle part and the refectory, which is a complex single continuous system of thin-walled spatial structures of various along the outline of the median surfaces.

The work is devoted to solving the problem of the lack of draft of the existing chimney when operating hot water boilers at full capacity. Thermal and aerodynamic calculations were performed. Thermal calculation was carried out with diff erent loading of hot water boilers and the number of operating burners. The options for the operation of boilers according to the regime map and test protocols are considered. In the aerodynamic calculation for the sections, the resistance of the gas ducts was determined, the chimney was calculated. A fl ue gas pump is installed to remove combustion products from hot water boilers. This will ensure the parallel operation of two hot water boilers over the entire load range.

A study of the reagent removal of phosphates from domestic wastewater is presented. The research involved works, the authors of which describe methods for extracting phosphorus compounds from water. The article compares the removal of phosphates from wastewater by various methods in comparison with reagent methods. The analysis of existing technologies for regenerative dephosphorization of wastewater has shown that a promising direction is the search for new reagents for extracting phosphates from wastewater. Preference is given to such reagents as calcium oxide and hydroxide, iron chloride and sulfate, aluminum sulfate. The most eff ective for binding phosphates is the calcium cation, since a greater amount of hardly soluble compounds are formed with it.

The article provides a retrospective analysis of existing approaches to the complex reconstruction of block buildings, which developed against the background of various scientifi c paradigms. Within the framework of the paradigm of territorial development management, a new investment and prognostic approach to the complex reconstruction of historical quarters is proposed on the example of Samara. The historic quarter is viewed as a planning module for the transformation processes of a sett lement. Reconstruction of the historical quarter is presented in the aggregate of problems of preserving and developing its buildings, providing residents with the necessary level of engineering, social and transport infrastructures. A method for calculating the rates of return for complex reconstruction is proposed, which serves to test the modes of the security zoning proposed for a historical sett lement. Particular att ention is paid to the preparation of initial data for calculating the rates of return for complex reconstruction for a number of quarters selected as reference.

For the Samara architecture of our time, the urgency and priority of the problem of preserving and developing the historical center is obvious. This study is at the forefront of the current controversy on this issue and gives its own version of the solution to the problems. The practical signifi cance of the research is a new articulated and visualized experience of reconstructive actions in the historical environment. The method of urban planning analysis of the site in order to identify the reserves of the territory is proposed. Methods of working with the architectural form necessary for preserving the morphotype of the old city in the conditions of modern development are shown. Conclusions and recommendations based on specifi c urban planning material are formulated.

The article analyzes the world experience in the design and construction of religious buildings and spiritual and educational centers of Islam at the turn of the XXXXI centuries. The most famous modern examples of religious objects of Islam are given. Similar temporal, stylistic, structural, and planning features of temples are classifi ed. Based on the performed analysis, conclusions are drawn about the prevailing trend in the design of Islamic religious buildings - historicism. It is shown that an important design concept is the openness and tolerance of the object in relation to the city and the creation of a harmonious environment around the new structure

This article discusses the problem of constant growth in the level of motorization, amid a decrease in the use of public transport. It touches upon the functioning of urban public transport in the context of the concept of sustainable mobility. On the example of the city of Samara, using a sociological survey, an analysis of the comfort of the transport system was carried out. The analysis of the transport accessibility of the districts of the city of Samara relative to the historical center of the city is presented. An assessment is made of the readiness of the city and, in particular, the transport infrastructure for the introduction of paid parking zones in the central part of the city. The studies on the assessment of the probability of abandoning a personal car in favor of public transport are presented. The criteria for reducing or completely abandoning the use of a personal car in favor of public transport have been identifi ed.

The infl uence of the geometric dimensions and confi guration of slot contactless seals on the obliteration of the gaps of plunger pairs at the design and calculation stage of drive systems of electric power systems units is considered. The combined eff ect of working fl uid contamination and the adsorption eff ect on the overgrowth of the living section of the channel was revealed. The fl ow rate during sample shedding was reduced simultaneously as a result of the channel overgrowing with contamination particles and adsorption, i.e. the formation of boundary fi lms on the channel walls. Leaks through the gap at concentric and eccentric position of the plunger in the sleeve are determined. The minimum gap is found, at which the obliteration process is stabilized and loose mud formations are washed away by the fl ow of the working fl uid. The infl uence of the pressure drop at the ends of the slot gap on the channel obliteration process was revealed. With an increase in the pressure drop, the process of stratifi cation of adsorbed layers of polar molecules accelerates, resulting in an increase in the number of contamination particles trapped in the gap per unit of time. With an increase in the temperature of the working fl uid, the process of channel obliteration accelerates, which is confi rmed by experiments. With an oscillating plunger, the fl ow through the annular gap is less than with a stationary one. This is due to the fact that the oscillating plunger occupies a position in the sleeve close to the concentric one, at which leaks are minimal. A stable fl ow rate is obtained when the working fl uid fl ows through the gaps of the plunger pairs performing reciprocating oscillating movements.