Introduction. Reversible plate compactors are soil compaction machines with a flat operating device, having two or more unbalanced shafts and ability to reverse the direction and movement speed. Reversible plate compactors may be driven by gasoline, diesel or electric engines. The efficient operation of reversible plate compactors is only possible with the rational selection of technical specifications, such as oscillation frequency and driving force of the vibration exciter, base plate width, engine power, etc. To establish correlations between the technical specifications of reversible plate compactors, to assess the influence of the engine type on the main parameters and to identify the areas for improving this type of equipment, the statistical analyses was conducted.

Materials and methods. 484 models of reversible plate compactors were scrutinized. The information on the models were obtained from official websites of plate compactors manufacturers and their dealers. Data processing was performed in Microsoft Excel.

Results. The variation ranges of the main parameters were determined and regression equations for correlations between the oscillation frequency of the vibration exciter, the driving force, the width of the base plate, the relative exciting force and the mass of reversible plate compactors were derived. Correlation coefficients were obtained for each regression dependence. The influence of the engine type on the variation range of reversible plate compactors’ main parameters was analyzed.

Conclusion. The type of engine has almost no effect on the parameters of reversible plate compactors in the corresponding mass ranges. Relatively low correlation coefficients let us suggest that manufacturers do not have reliable methods for justification of the technical specifications of reversible plate compactors. The obtained correlations may be recommended for verification of some technical specifications of reversible plate compactors. In recent decades, the values of oscillation frequency and relative exciting force have increased significantly, which affects the nature of interaction between a reversible plate compactor and soil.

Introduction. Experimentally revealed disadvantages of domestic complex safety devices in the part of load capacity limitation and parameters registration are described. The reasons why it is inadmissible to re-equip cranes under the control of foreign safety systems to the existing domestic devices are explained. It is suggested to achieve the safety of such cranes through the development of safety devices that take into account the dynamic characteristics of a particular crane and control algorithms of its drives.

Materials and methods. The study was done using the developed safety device realizing the functions of load capacity limitation, automatic determination of the parameters of the load capacity limiter algorithm, determination of the crane operation intensity. The description of these algorithms in relation to cranes equipped with frequency control system is given. Experimental determination of operational parameters of the device is carried out on an overhead crane equipped with the ControlPro safety system (KoneCranes).

Results. The use of the device allowed to decrease the dynamic coefficient in the whole range of lifted loads masses. A twofold reduction of the dynamic component was obtained when lifting near-nominal loads. The accuracy of characteristic number determination was 1.3%.

Discussion and conclusion. It is demonstrated that the developed algorithm of load capacity limitation allowed not only to increase crane security, but also to reduce the loading on the crane, in comparison with the standard safety system. The accuracy of operating parameters determination in conditions of real technological process satisfies the requirements of normative documentation. Thus, the possibility of duplicating or replacing some functions of the standard safety system by using the developed device is shown.

Introduction. Industrial tractor units differ from agricultural tractor units by the greater weight of the working equipment, a wide range of soil conditions and the cyclicity of the technological cycle. An integral part of the operation of bulldozer units is slippage, which is not regulated by GOST. However, large amounts of slippage result in a drop in operating speed and technical performance. Therefore, the approaches developed for optimizing the productivity of tracked agricultural tractor units (where slippage is regulated at 5%) require clarification. The aim of the study is to determine the influence of specific traction-speed characteristics of a bulldozer unit on its technical productivity.

Materials and methods. Technical productivity was defined as the ratio of the volume of developed soil to the time of the working cycle. The volume of developed soil was expressed through the specific traction indicators of the tractor unit. The time of the working cycle was expressed through the speed indicators of the tractor unit. As a result, the dependence of technical productivity on the specific traction-speed indicators of the industrial tractor unit was obtained.

Results. The analysis of this dependence showed the presence of a clearly expressed maximum, which for the bulldozer unit is observed at 18% slippage. Optimal specific traction efforts for various soil conditions were determined. The evaluation of the speed indicators of the bulldozer unit showed the possibility of additional increase in technical productivity due to the growth of the operating speed.

Conclusions. A productivity coefficient has been obtained that allows comparing the technical indicators of tractor units of different classes. It has been established that for bulldozer units with a semi-rigid suspension, operating on dense soils, the optimal specific traction efforts are 0.75...0.89. Further increase in technical productivity is possible by increasing the working speed while maintaining (or increasing) the ratio of idle speed to working speed.

Introduction. The working process of milling asphalt concrete pavements. The working process of asphalt concrete milling is considered as a set of destruction processes of the stone fraction, bitumen bonds and other phenomena unrelated to the formation of new surfaces. The conducted analysis is based on the assessment of the ratio of energy spent on milling in general and the energy needed for the formation of new surfaces made from separate fractions of asphalt concrete granulate and crushed stone aggregate.

Materials and methods. The work is based on carried out experimental studies of the granulometric composition of asphalt concrete granulate obtained by milling crushed stone-mastic asphalt concrete pavement, and, separately, the stone fraction of asphalt concrete got by burning out a bitumen matrix. A standard method was also used to determine the specific energy of destruction of bitumen bonds when determining the fracture disruption resistance of a sample in tension while splitting.

Results. As a result of sieving, granulometric curves of the composition of asphalt concrete granulate and stone fraction were obtained. Calculation methods have determined the components of energy consumption for the formation of new surfaces made from asphalt concrete granulate and new surfaces from stone fraction.

Discussion and conclusion. At the end of the study, quantitative ratios of various fractions of asphalt concrete granulate of stone-mastic asphalt concrete formed during milling, as well as the crushing grade of stone fractions, were obtained. The specific energy consumption during the milling of asphalt concrete has been determined. It was found that the largest part of the energy during milling (64.7% for this study) is needed for the destruction of bitumen bonds. The vast majority of this energy is used for the formation of the fine granulate fraction. An insignificant part of the energy is spent on the destruction of the stone fraction. In general, the share of energy consumption aimed at the formation of new surfaces accounts for this study 66.14% of the total energy costs. The research development prospects of granulometric analysis for evaluating the effectiveness of the asphalt concrete milling process have been noted.

Introduction. The growth of the urban area has led to the need to transfer landfills for the disposal of solid municipal (household) waste (MSW) to more remote locations on new sites. Representations and approaches to cargo transportation planning are an essential factor, separate planning of individual applications does not allow determining the results of future work with sufficient accuracy, since such an approach does not allow taking into account the interaction of rolling stock from different routes with each other and loading machines. The purpose of the study is to design the transportation of MSW in regional communications based on a discrete approach and theoretical provisions of operational planning of road freight transportation.

Materials and methods. Within the framework of the conducted research, a normative approach was applied to the planning of freight transportation costs and descriptive models for describing the functioning of road transport systems of regional road freight transportation.

Results and discussion. The solution of tasks related to the design of cargo transportation, including in regional communications, is due to the need in advance, prior to experience, knowledge of the results of future activities, since it is impossible to accumulate the work of road transport and then fix it. The results of cargo transportation depend on many factors, including the availability of a design methodology that allows you to adequately reflect the processes of their implementation. The use of mathematical modeling made it possible to reliably build plans for the transportation of MSW and determine the cost of their implementation.

Conclusion. It has been revealed that possible downtime of both road trains and excavators is the reason for not fulfilling the operational transportation plan defined by separate planning. The use of the same rolling stock for customers with different transportation distances in the region will be accompanied by different costs.

Introduction. Within the framework of the transformation of the passenger transportation industry of the Russian Federation, the relevance of assessing the current state of the public transport service system in the subjects of the Russian Federation is determined on the basis of the parameters laid down in current and prospective regulatory legal acts.

Materials and Methods. The research uses current regulatory legal acts of the federal and regional levels in the field of public transport services, data from the administrative-territorial division of the subject of the Russian Federation, current registers of inter-municipal and municipal routes, up-to-date statistical information on the population. The following research methods were used: analysis, survey, formalization.

Results. The research presents a methodology developed by the authors for rapid assessment of the current state of the public transport service system in the subject of the Russian Federation, including an algorithm for its application. The methodology is based on the assessment of six criteria, which are aggregated indicators of the parameters of public transport services in the areas of accessibility, safety, reliability and comfort. The results of the testing of the technique in the Omsk region are presented.

Discussion and conclusions. The results obtained allow us to identify problem areas for which it is necessary to develop and implement measures to improve the quality of public transport services in the short term. The proposed methodology is not a substitute for the methods approved by the current regulatory legal acts, and can be used at the initial stage of development and updating of transport planning documents of the subject of the Russian Federation.

Introduction. Modern wheeled vehicles with electric and hybrid power plants are becoming more and more widespread. It is obvious that with the increasing number of wheeled vehicles with electric and hybrid power plants, there is a need to conduct a full-fledged and qualitative study of the working processes of wheeled vehicles both at the stages of production and fine-tuning at manufacturing enterprises, and in operating conditions at the service stations and other organizations. The research of the technical condition of a wheeled vehicle with electric and hybrid power plants with a classic layout of the power unit and transmission (front or rear axle drive) is quite possible to be conducted on existing stands. But when testing wheeled vehicles with electric and hybrid power plants with all-wheel drive or with an electric motor generator for each drive wheel, a problem arises due to the lack of methods and means to measure traction force on each wheel individually.

Materials and methods. This section provides an analysis of the possibilities of conducting a study of the technical condition of wheeled vehicles with electric and hybrid power plants on modern power and inertia stands that apply the principle of reversibility of motion.

Results. Methods have been developed to study the traction and dynamic properties of wheeled vehicles with electric and hybrid power plants, to implement it was proposed to use developed research stand complex, which includes a hybrid stand with control and measuring systems that allow to determine forces and power on the driving wheels of vehicles, as well as time and kinematic parameters of its functioning process. During the experimental studies, the results of Kia Soul EV and Toyota Prius NHW20 operation processes were obtained, their power and kinematic parameters were analyzed.

Conclusion. As a result of the study, it has been proved that in order to ensure highly informative and stable test modes of wheeled vehicle’s operation in the process of studying their traction and dynamic properties, it is necessary to use hybrid stands.

Research relevance. Modes accompanied by increased sliding of a wheel with negative viscous friction, characterized by reduction of friction force at growth of sliding speed, can arise at the movement of the vehicle. In these cases, a loss of stability may occur, resulting in the excitation of auto-oscillation phenomena in the electromechanical system (road-wheel-mechanical drive-electric motor). The emergence of this process sharply increases the dynamic load of the system, which can lead to its failure or breakdown. As a consequence, the development of suppression methods of auto-oscillation phenomena is considered to be an urgent task.

Purpose of the research. Verification of operability and efficiency of the suppression method of auto oscillations in the electromechanical system of wheel drive during braking of the vehicle.

Materials and Methods. With the help of Lyapunov’ function analysis for the electromechanical system of wheel drive the suppression method of auto oscillation phenomena is substantiated. The study of the algorithm performance has been carried out with the use of MATLAB Simulink program complex.

Research results. The operability and efficiency of the algorithm is proved by methods of simulation mathematical modeling, which allows its further use in the development of traffic control systems. In case of braking of the vehicle equipped with antilock braking system with the function of suppression of auto oscillations on a slippery support base the reduction of amplitudes oscillation of angular velocities of wheels by 80% and braking moments by 96% is observed. When this vehicle is braked on a high adhesion base, the amplitudes are reduced by 98% in angular velocities and 81% in torques. In simulation modeling of vehicle braking dynamics on a support base with low adhesion properties it has also been shown that in these cases the evasive maneuver can be performed, which indicates on the increase in controllability and active safety of the vehicle.

Conclusion. The practical value of the study lies in the possibility of using the developed algorithm for suppressing auto oscillations in practical application as part of vehicle control systems. The developed algorithm can be used on vehicles of different classes equipped with individual traction electric drive of driving wheels.

Introduction. The calculation of road pavements according to strength criteria is performed for the design period of the year, when the soil moisture reaches its highest values. Such moisture is called design moisture and is established by determining the highest value at a given one-sided confidence probability, taking into account various corrections for the terrain, roadbed design and shoulder reinforcement. It would seem that everything is done correctly, but in some cases, the design moisture reaches high values, within 80...90% of the moisture at the fluidity limit. Such values of design moisture are greater than the full moisture capacity of some types of soil. In this case, the physics of the soil water saturation process is violated.

Materials and methods. To calculate the total moisture capacity, the physical principles of engineering geology are used, based on a three-phase physical model of dispersed soil. In this model, each of the three phases (solid, liquid and gaseous) occupies a certain volume, and mineral particles and liquid have mass and weight. Based on this model, classical fundamental formulas are obtained that allow determining any physical characteristic of the soil. These fundamental dependencies are used to calculate the total moisture capacity. The calculation of the total moisture capacity is used when constructing a line of zero air content in the soil with its standard compaction. It is shown that the total moisture capacity depicted on this line is the highest moisture content for soil compacted to this state.

Results. A method for calculating the total moisture capacity of the soil at different compaction coefficients is proposed. Its value in winter is taken as the minimum possible compaction coefficient, calculated taking into account the correction of Yu.M. Vasiliev and A.S. Eremin, which takes into account soil decompression during water freezing. The total moisture capacity of the soil, calculated with a minimum compaction coefficient, is a limit value that the calculated humidity cannot exceed.

Conclusion. The authors’ ideas about the physical condition of soils are presented, according to which their calculated humidity cannot exceed the full moisture capacity at a given degree of compaction. Therefore, the value of the calculated humidity, expressed as a fraction of the humidity at the yield point Wр / WТ , is proposed to be limited to the relative value of the total moisture capacity Wsut / WТ .

Introduction. According to the legislation of the Russian Federation and the current regulatory documentation, when designing buildings and structures of high consequences, it is necessary to make calculations for a progressive collapse caused by an emergency situation. There are four methods of analyzing buildings and structures for progressive collapse: linear-elastic static (quasi-static) method; nonlinear static method; linear-elastic dynamic method; and nonlinear dynamic method. A comprehensive analysis procedure with the use of all four methods is considered to be most effective, but such a comprehensive analysis requires additional work of the design engineer, therefore it is of practical importance to use one of the analysis methods mentioned above. This article describes the peculiarities of calculating metal structures for progressive collapse using the quasi-static method.

Materials and methods. A compartment of an industrial building of high consequences class was taken as the object under study. The static calculation of the spatial scheme and the constructive calculation of the frame elements were performed in the Lira 10.12 program. Within the object under the study, we analyzed three options for the transition from the primary design scheme to the secondary one. In addition, we considered two more options that do not imply the removal of load-bearing elements from the design scheme after their failure.

Results. Despite the fact that, when checking the selected columns for progressive collapse, we obtained ambiguous results for complete movements of nodes adjacent to the lower ends of the columns being removed (loosened) as a result of special impact, and some elements were not checked for design combination of forces, this calculation scheme should be considered resistant to progressive collapse.

Discussion and conclusions. The calculation options used for progressive collapse analysis by the quasi-static method, when checked for design combination of forces, have shown identical results. The difference between the calculation options based on removing parts of the elements in which their operation fails, and the options based on unbinding these elements, has been about 2-3%.

Introduction. The increase in traffic intensity and the prospects for the development of high-speed railway transport require solving the problem of the effectiveness of vibration protection of transport infrastructure facilities by developing innovative solutions. Currently, the issues of combating vibration in relation to the span structures of bridges and overpasses are insufficiently studied. The purpose of the work is to study the promising directions of vibration protection of bridge structures based on the use of dynamic vibration dampers.

Research methodology. To achieve the goal of research and implementation of effective technical solutions in the field of vibration protection of bridge structuresimproved design of dynamic vibration damper is proposed in which inertial mass is fixed on two springs, upper of which is connected to structure protected from vibration, and lower spring to base or foundation of object. Oscillations are damped due to oscillations in antiphase due to free and forced oscillations of auxiliary inertial masses protected from vibrations. This technical solution makes it possible to balance forces of elastic interaction of damping device and object protected against vibration and moments from these forces.

Results. As a result of experimental studies of the prototype of the improved dynamic vibration damper installed on the vibration stand, it was found that the vibration levels in all directions significantly decreased, including in the vertical direction by 5.7 times.

Discussion and conclusion. The obtained positive results of experiments and the relative simplicity of the proposed design make it possible to propose this method of vibration protection of superstructures for both newly designed and already in operation facilities. It is especially important to minimize the possibility of resonant phenomena and pitching. The results of the study will make it possible in the future to ensure the effectiveness of vibration protection of oscillating machines, mechanisms and infrastructure facilities.

Introduction. It is known that flooded, blocked soils prevail in the North of Russia and in the territory of its Arctic zone. Such soils have a low bearing capacity, which reduces the possibility of their use in the construction of winter roads. Compaction (crimping) of blocked soils changes their thermophysical and physico-mechanical properties by changing the modes of freezing and thawing of weak bases, as well as the bearing capacity of overland winter trucks in wetlands. The article reflects the results of experimental studies of changes in the thermophysical and physico-mechanical parameters of the blocked soil at different degrees of its compaction.

Methods and materials. Low-moisture soil with a high content of organic matter (peat) of more than 50% was used for research. It was compacted with loads, the magnitude of which is typical for sealing (crimping) operations of weak blocked bases on autosomes (0.01, 0.03 and 0.06 MPa), and frozen in a chamber to a temperature of -15 °C. Temperature control was carried out at different depths at predetermined intervals. To do this, we put together a device, the main elements of which are DS18B20 brand thermal sensors and an Arduino Nano microcontroller. The thermal conductivity of thawed and frozen soil was determined using the MIT-1 probe device. A dynamic density meter D-51 was used to determine the strength (hardness) of the samplesand the universal penetrometer PUS-3M.

Results. The properties of the studied organic soil have been clarified. The heat capacity of this soil is determined depending on its humidity, temperature and density. The influence of the degree of soil compaction on the kinetics of its freezing is estimated. The results of the study of the dependence of the conditional strength (hardness) of the soil at different temperatures and densities, as well as the results of the interpretation of the results of dynamic zonation and the modulus of elasticity for the studied blocked soil are presented.

Conclusion. Compaction (crimping) of the blocked soil increases its thermal conductivity and the rate of freezing of the upper layer of the swamp, which helps to accelerate the commissioning of the winter truck. Compaction (crimping) of the blocked soil significantly increases its strength during freezing, which determines an increase in the bearing capacity of autozymers in swamps. The most promising use for operational control of the density and strength of a frozen peat slab on autozymers is dynamic sensing methods with penetrometers of various designs. The results of determining the conditional strength index (hardness) of peat soil using probing with a dynamic density meter and a universal penetrometer are obtained.

Introduction. Currently, in road construction, in order to reduce energy costs and harmful emissions, warm asphalt concrete mixture technologies are being increasingly used. One way to reduce the temperature of asphalt concrete mixture prepared is to use additives based on natural and synthetic waxes. In this regard, it is important to study the influence of wax additives on the properties of bitumen binder as a basic component of asphalt concrete mixture. The adhesion between the binder and the mineral filler is the most important property that determines the durability of an asphalt concrete pavement. The purpose of this article is to study the effect of synthetic wax additives on the adhesive properties of bitumen.

Materials and methods. The characteristics of the studied synthetic wax additives Viskodor PV-2, Sasobit and Licomont BS-100 have been presented. To simulate binder aging, the heating method in a thin layer, according to GOST 18180, was used with the temperature control time increased to 9 hours. To assess the adhesion between original and modified bitumen binder, as well as the aged binder, the method of boiling stone material coated with bitumen was used, and the assessment of its appearance in accordance with GOST 11508 was made. The study of the adhesion mechanism for the bitumen binder and the mineral filler was carried out by means of spectral analysis.

Results and discussion. The influence of synthetic wax additives on the adhesion between bitumen binder and mineral material was analyzed. A change in the adhesive properties of bitumen modified with the studied additives during thermal-oxidative aging was revealed. A comparison was made of the IR spectra of the original and modified bitumen before and after interaction with stone material and the differences in the mechanisms of affecting the adhesion to the mineral filler by the introduced additives were determined. It has been established that the Viskodor PV-2 additive significantly improves bitumen adhesion. Moreover, the effect of improved bitumen adhesion with this additive remains after thermal-oxidative aging, though slightly reduced. Imported additives Sasobit and Licomont BS-100 have a significantly less impact on the adhesive properties of bitumen.

Сonclusion. The results obtained show that the use of synthetic wax additives improves the adhesive properties of bitumen, which can positively affect the durability of the road surface. Since the domestic additive Viskodor PV-2 is superior in the effect of improving the adhesive properties of bitumen compared to the studied additives Sasobit and Licomont BS-100, the introduction of this additive into production instead of expensive imported additives will provide both improvement in the quality of asphalt concrete pavement and reduction of costs.

Introduction. One of the rising architectural trends of the present time is to increase the comfort and aesthetics of the territories of populated areas through artistic improvement, a significant role in which is given to various types of small architectural forms. The most budgetary and, at the same time, reliable and durable material for them is architectural concrete. The bottleneck in the use of concrete for the manufacture of small architectural forms is the relative difficulty of giving it complex spatial configurations. At the current level of development of concrete work technology, this drawback can be easily overcome through the use of construction 3D printing technology. The aim of the work was to develop effective architectural concrete for the manufacture of small architectural forms using the 3D construction printing method, based on composite binders containing weathered quartzite sandstones as a mineral additive, as one of the types of local energy-efficient raw materials. Materials and methods: The section presents comparative characteristics of weathered and unweathered quartzite sandstones.

Results. The data on the dynamics of component grinding; compositions and characteristics of composite binders and fine-grained concretes based on them; results of manufacturing a pilot batch of small architectural forms using the construction printing method are presented.

Discussion and conclusions. The description and analysis of the obtained experimental data are presented. The conclusions are formulated in which it is noted that for the organization of the production of modern small architectural forms, the technology of 3D construction printing is used, which allows the implementation of complex various spatial forms of products with any level of individualization without increasing costs. The developed molding mixtures confirmed the high efficiency of using weathered quartzite sandstone as part of a composite binder and technogenic sand. The introduction of the developed materials meets the requirements of energy and resource conservation, since the consumption of Portland cement and non-renewable natural resources is reduced.