The article deals with the improvement of structural solutions of steel reinforced concrete slabs with external reinforcement. The possibility of creating an orthotropic steel reinforced concrete slab on a profiled deck with a continuous or discrete puff located perpendicular to the direction of corrugations is determined. This kind of construction works in bending in two directions along the wave and across the wave. This will allow slabs to be supported on three and four sides, which will make it possible to redistribute the pressure on the supports and reduce the stress concentration at the joints between the slab and the support structure. A continuous puff is assumed to have the same cross-section along its entire length, while a discrete puff can have a variable thickness. Two variants of the calculation of this structure are found, as a monolithic rod with a sprengel chain and as a composite rod with an explicit contact zone. When the stiffness of the contact zone is close to absolute, the rod can be considered as a monolithic rod. An experimental study of the characteristics of the contact zone of the profiled deck organised by means of stamping on the inner side of the corrugation is required, taking into account the perpendicular location of the corrugations to the span of the beam and the concrete part of the section. A comparative analysis of the existing techniques has been made and further experimental investigation methodology has been determined. A numerical evaluation of stresses in a steel plate has been carried out.

Keywords: steel reinforced concrete slabs, orthotropic slabs, calculation methods, contact zone, stamping

The article proposes a new approach to the method of calculating a rigid foundation on a nonlinear and rheology deformable half-space, taking into account the external load variable in time. It is proposed to take into consideration the nonlinearity and rheology of deformation on the basis of modern phenomenological theory using the integral method of successive iterations, which makes it possible to take into account the time-variable mode of external loading, which is characteristic of the stage of construction and operation of structures. An algorithm for the numerical solution of the problem under the conditions of the regime action of external loads using the method of integral estimates based on the step method and successive approximations is presented.

Keywords: rigid foundation, foundation deformation, regime loads, deformation rheology, integral method, phenomenological theory

The article discusses a method for taking into account the compression of concrete using standard formulas when calculating using an inverse numerical-analytical method, taking into account the actual rigidity of concrete filled steel tube elements. The inverse numerical-analytical method makes it possible to calculate concrete filled steel tube elements for strength and stability under eccentric compression. Dependencies are presented showing the possibility of taking compression into account at various eccentricities and flexibility.

Keywords: concrete filled steel tube elements, CFST, inverse numerical analytical method, nonlinear deformation model, concrete compression,concrete filled steel tube column, eccentric compression

Polyethylene pipes are widely used for the construction of gas distribution networks. The disadvantage of pipes is their low mechanical strength. When crossing various artificial obstacles in pipes, unacceptable stresses may arise, causing destruction along the pipe body. To make a decision on the installation of a casing in such areas, it is necessary to determine the stability criteria for the circular cross-section of polyethylene gas pipelines. The article reveals that of the two equations proposed by SP 42-103-2003 for the critical value of external pressure of polyethylene gas pipelines, in practice only one can be used, for which the criterion value is always minimal.

Keywords: polyethylene gas pipelines, dynamic load, stability of the circular cross-section, external pressure

Welding is the main method of joining plate steel. Its use leads to significant residual welding stresses. Residual stress can significantly affect the load-bearing capacity of long-span steel bridges. In this work, a finite element calculation of residual welding stresses of steel sheets up to 100 mm thick was carried out, and the distribution of surface residual stresses and the influence of sheet thickness on the residual surface stress were identified.

Keywords: steel bridge, plate steel, welding residual stresses, finite element method, welded joint, stress distribution

The problem of energy efficiency and rational use of energy resources in housing and utilities sector remains relevant over the past years. In this regard, the reduction of heating and hot water costs remains under continuous review of specialists all over the world. The article discusses the issues of using low potential thermal energy of domestic wastewater for hot water heating. Data on wastewater temperature in various locations are presented. The main designs of wastewater heat recovery units and the features of their application are considered. It is shown that the temperature parameters of residential building wastewaters differ significantly and depend not only on the climatic zone, but also on the regional features of water consumption. It is concluded that in process of wastewater heat recovery it is possible to reduce wastewater temperature at least by 5 ºС, and in hot season ‒ by 10-15 ºС. The analysis of literature data lead to the conclusion that wastewater heat recovery units are more promising and viable at building level as well as sewer or wastewater treatment plant level. For these cases, greater efficiency can be reached by using heat recovery facilities with a heat pumps.

Keywords: hot water supply, sewage, low potential heat, wastewater temperature, heat pump, heat exchanger, waste water heat recovery, energy saving

The results of numerical modeling of wooden beams strengthened of composite materials based on carbon fiber are considered. Modeling of beams strengthened of composite material was carried out in the ANSYS software using deformation diagrams. The reliability of the modeling methodology was assessed by comparing the results of a numerical study with the results of a physical experiment obtained during testing of models of wooden beams strengthened of composite materials based on carbon fiber.

Keywords: carbon fiber, carbon composite materials, strengthening of wooden structures, external reinforcement of wooden beams

The article raises the problems of preserving historical architectural and natural complexes on the example of the Peter and Paul Park in Yaroslavl. In the Introduction to the article, attention is drawn to the importance of the problem of preserving historical monuments of architecture or art not only in the capital cities, but also on the periphery. The following are the main methods used in the work to assess the state of the architectural and park ensemble, to identify its characteristic architectural and landscape features and to develop a theoretical conservation model. In the main part of the article, the historical stages of the formation of the architectural and park ensemble of the Peter and Paul Park, their influence on the final appearance of the ensemble are considered; a comparative analysis with similar architectural and park ensembles is given, common characteristic features are identified and the principles of the formation of the Peter and Paul Park are established. As a result of the conducted research, a model of preservation of the Petropavlovsk architectural and park ensemble of Yaroslavl is proposed, presented in the form of a master plan of the park territory, which contains proposals for the reorganization of the territory, pedestrian park network and restoration of historically significant structures. In the final part of the article, the main conclusions based on the results of the study are formulated.

Keywords: architectural and park ensemble, Peter and Paul Park, Yaroslavl Big Manufactory, regular layout, theoretical model of conservation

High-rise buildings with CLT (cross-laminated timber) load bearing structures are being more actively developed in many countries. CLT-panels are lightweight, ecological and easy to assemble. In the article types of strengthening of three-layers and five-layers CLT-panels with carbon, basalt and flax fiber reinforced polymers (FRP) are considered. They can be used for panels under exploitation to reduce influence of defects and increase load bearing capacity and stiffness or in the production stage to reduce thickness and weigth of constructions. Known works of international authors are analyzed. Bending behaviour of externally reinforced CLT-panels is described. Areas that deserve further investigation are determined. They include investigation of different composite materials and wood types used for CLT-panels' production.

Keywords: CLT, composite, cross-laminated timber, external strengthening, FRP, high-rise building, lamella, reinforcement, timber structure, wood

The Russian Federation is a multi-religious state, which has recently seen an increase in the construction of various religious buildings. At the same time, the bulk of the churches being built are small buildings, located, as a rule, in villages and small towns and designed for simultaneous visits by up to 120-150 parishioners. Various materials are used for their construction, including wood. Usually these are log or block buildings, but it is also possible to use other wooden housing construction systems, including light frame ones. The theoretically possible remoteness of towns and villages from large district and regional centers, the impossibility of delivering large-sized beams and logs, the lack of their own production base and other factors lead to the need to use ordinary boards in wooden frame structures. As an example, we consider the construction of the Church of the Transfiguration of the Lord in one of the farms in the Rostov region, the load-bearing structures of which are made using light-frame house-building technology. The presence of open space in the central part of the Temple and the placement of an octagon-shaped superstructure above it required the use of a supporting structure made of steel I-beams. Thus, the structure of the Temple frame is a metal-wood system. The article shows that the combined use of steel and wood in light-frame buildings ensures a rational organization of the space of religious buildings.

Keywords: religious building, temple, belfry, octagon, narthex, altar, wood, light frame building, beam, I-beam, supporting structure

The influence of blast furnace ground granulated slag on the kinetics of strength gain of concrete prepared with a composite binder was revealed. The composite binder contained Portland cement in amounts of 70, 60 and 50%, and the rest was ground granulated slag. It has been established that at the early stage of strength development, concretes made with a composite binder have a strength lower than concrete prepared with Portland cement by 10-24%. However, at the age of 28 days, the strength of concrete using a composite binder corresponds to the strength of concrete using Portland cement. Using polycorboxylate hyperplasticizers, it was possible to obtain concrete with a W/C ratio of 0.25-0.35, which made it possible to obtain high early strength exceeding control compositions by 10-20%.

Keywords: portland cement, grn slag, grinding, composite binder, kinetics of strength gain, hyperplasticizer, kinetics of strength gain

The world's reserves of renewable energy sources are steadily declining, but the comfort of life in modern society should remain at the same level. The modern solution of the problems of thermal protection of facade systems of buildings is associated with the analysis of the specific heat capacity of the materials included in their composition. The use of new energy-efficient materials is becoming especially relevant. Such materials include vacuum thermal insulation panels, which significantly reduce heat loss in comparison with traditional thermal insulation.

Keywords: energy efficiency of buildings, thermal protection of facade systems, thermal insulation, vacuum thermal insulation panels, construction production

The article presents the results of a survey of two industrial buildings, conclusions about their emergency technical condition and the inexpediency of restoration. Modern methods of demolition and dismantling of buildings in the cramped conditions of the existing urban development are analyzed. The main technologies of recycling dismantling and disposal of construction waste generated during the dismantling of buildings are considered: "smart demolition" and the technology of piecemeal disassembly of buildings with the reuse of materials, products and structures. Comparing the two methods of recycling dismantling for application to the objects under consideration, it is concluded that the first method of "smart demolition" implies the destruction of all building structures, while the second is more rational in terms of resource conservation and economic efficiency by reuse of serviceable structures. The technology of piecemeal disassembly of buildings with the reuse of structures requires the development of regulatory, organizational and marketing measures.

Keywords: building inspection, demolition, dismantling, dismantling methods, smart demolition, recycling dismantling, reuse of structures

Elimination of the consequences of emergencies during rescue operations will be successful with the use of reliable modular lifting equipment. The proposed concept of the mobile equipment system contributes to the use of layer-by-layer dismantling of the rubble of destroyed multi-storey buildings and structures. The main structural elements of the system of mobile lifting equipment are presented.

Keywords: earthquakes and disasters, mobile equipment, lifting device, time minimization, modular device

The article gives a description of the developed design of a sample of the connection of wooden elements, which is devoid of the shortcomings of existing technical solutions that allow simulating the actual operation of real wooden structures. The design makes it possible to increase the reliability of the test results, simplifies the test procedure and the test results processing process. The developed design of the sample fully reflects the actual work of the real joints of the beam cage of a wooden building, causes a stress-strain state in the sample, to a large extent similar to the stress-strain state of a real joint due to the correct application of the basic provisions of the similarity theory to connect the model with the full-scale construction of a wooden buildings, schemes for applying the load to the sample and methods for conducting experiments.

Keywords: wooden structures, timber, joining of wooden elements, testing of a sample of connecting wooden elements, wooden beam, main beam, secondary beam, metal plates, screws, reliability improvement

The paper considers the problem of the arrangement of the abutments of newly erected driveways and roads of agricultural production enterprises to existing roads and driveways. When connecting the "pies" of the roadways of the projected driveways with the existing landscaping, it is necessary to solve the problem of preventing cracking in the coating at the places of the thickness difference of the structural layers. In the article, this problem is solved both from the technical side, by ensuring the joint work of the new and existing road structure, and from the normative one by assigning the projected passage to the IVB category road, in accordance with SP 37.13330.2012, which allows the construction of a road with curbs without curbs and, as a consequence, without storm sewers and sewage treatment plants.

Keywords: road network, cadastral boundaries, the design of the widening of the passage, the technical solution of the junction of roads, transverse profile

Economic development directly depends on the creation of a network of roads of the highest category. Major road construction requires large capital investments and less funds are allocated for the operation of existing roads and infrastructure. Instead of replacing bridge structures, it is necessary to use their reconstruction. The article discusses the problem of reconstruction of bridge structures, namely the restoration of carrying capacity, which has decreased during many years of operation. The relevance of the study, its goals and objectives are noted. A classification of reinforcement structures according to various criteria is proposed. The types of bridge reinforcements often used in practice, their advantages and disadvantages, are analyzed. The presented material is illustrated with photographs of objects. Successful reconstruction directly depends on the qualifications of designers and contractors, since with insufficient reinforcement, the span continues to work and is overloaded and gradually collapses. A modern method of reinforcement based on the use of carbon composite is presented. Significant disadvantages of this method for strengthening bridges and its modification using a tensioning device to secure and tension the carbon lamellas have been noted. The use of a tensioning device allows the superstructure to be partially unloaded from permanent and temporary loads. The main conclusions are presented.

Keywords: bridge, strengthening, reconstruction, truss, carbon composite, lamella, load-carrying capacity, load-bearing capacity, tension

The object of research is C-shaped elements made of thin-walled cold-formed profiles. The subject of the study is the stability of C-shaped rod elements from thin-walled cold-formed profiles. Research goal: development of the calculation process by the finite element method and determination of coefficients of loss of the overall stability of thin-walled cold-formed rods. Method. A numerical-analytical research method is used to reduce the time and volume of settlement operations. The buckling coefficients are determined by finite element analysis of the buckling of the overall stability of cold-formed elements of light steel thin-walled structures using the software package. Result. This analysis results in a table of total weight coefficients for cold-formed thin-walled rods, which can be presented as a table for calculations on medical indicators—a comparative analysis of the inverse numerical-analytical calculation method with the finite element method using the computer program.

Keywords: stability, finite element method, thin-walled cold-formed profiles, steel, coefficients, software package, construction

The paper describes a model of behavior of the connection of wooden structures with glued rods when exposed to negative temperatures. The results of determining the resistance of wood to punching of a glued rod of reinforced joints of wooden structures at temperatures of -30°C, -70°C and +22°C are given. The characteristic features of the destruction of the reinforcing bar and the connection as a whole are revealed.

Keywords: wood, glued rods, extreme temperature and humidity conditions, indentation strength of adhesive bonding of metal rods

This article discusses the process of collecting initial data for the cadastral assessment of cultural heritage objects. It has been revealed that cultural heritage objects have a number of features among other real estate objects, so special attention should be paid to the methodology for assessing such objects. The purpose of the study is to analyze and identify problematic issues in collecting initial data on cultural heritage objects during the state cadastral assessment. The results of the study showed a number of problematic issues related to the type of cultural heritage object, its binding to the cadastral number and the possibility of interpreting the information received to bring it to automatic data processing.

Keywords: state cadastral valuation, cultural heritage object, collection of initial data, interdepartmental interaction, status of cultural heritage object

The paper considers the opportunities and obstacles to the integration of renewable energy sources (RES) in megacities on the example of Moscow. The paper analyzes the applied RES-based generation technologies, taking into account their applicability in large cities. Special attention was paid to the conversion of unused historical dams into small hydroelectric power plants (SHPP) as an integration of RES in megacities. Based on the results of the technical and economic analysis, it was found that the conversion of an unused dam on the Yauza River into a SHPP is justified.

Keywords: small hydropower, unused dam, megacity, renewable energy integration

One of the actual problems in the field of analysing loads and impacts on bearing structures is their identification. It means the point of application, the type of action and its intensity in cases where there is an impact result, but the parameters that caused this result are not determined. For example, it is an accident action, as a result of which the structure is deformed and collapsed. The solution of such problems arises when analysing accidents on load-bearing structures in construction, as well as when monitoring the deformed state of structures in time. The paper proposes to use the principles of neural network modelling to solve the problem of identifying the impact in the form of a concentrated force on the example of beam systems. The values of linear and angular nodal displacements at some action are considered as input data to neurons. As an example, the linearly deformable beam of constant stiffness is considered, the material of which is a continuous isotropic medium.

Keywords: neural network, deflections, load-bearing structure, displacement, deformation, identification

he article considers a plane problem of calculating the interaction of a culvert of different outlines with a soil embarckment, taking into account the constructive nonlinearity. Due to the impossibility of the soil to work in tension, the interaction of the pipe and soil is assumed to be uniulateral. In the problem, the outline of the pipe is changed, other parameters being equal. As the results of the calculation, the area of contact / separation and adhesion / slippage of the pipe with the soil is considered. Based on the results of calculations, recommendations are given for choosing the outline of culverts.

Keywords: constructive nonlinearity, frictional contact, unilateral constraints, linear complementarity problem, numerical models, finite element method

The article disrible a lot of novel patents in Civil Engineering, more of them from China

Keywords: patent's description, civil Engineering

On the example of the beams, the dynamics of systems with unilateral constraints are considered. The algorithm for calculating such systems as a combination of the step method of Newmark and the Lemke algorithm that determines the work scheme of the beam in each time step is proposed. Model tasks are considered with a harmonic exciting force, suddenly applied force, impulse exposure. The numerical convergence of the solution was investigated during the thickening of the temporary grid. It is shown that the accuracy of the solution significantly depends on the determination of the moment of changing the working schemes, since the error of the solution increases with an increase in the events “inclusion/off” of unilateral constraints.

Keywords: constructive nonlinearity, unilateral constraints, linear complementary problem, Lemke's algorithm, structural dynamics, Newmark's method