75504 2712-8172 4 80 2018 1-203

RAR RUS 3-14 12782293300 Military Space Academy named after A.F. Mozhaysky Sychova Anastasia amsychova@yandex.ru

St. Petersburg, Russian Federation

Emperor Alexander I St. Petersburg State Transport University Svatovskaya Larisa lbsvatovskaya@yandex.ru Military Space Academy named after A.F. Mozhaysky Starchukov Dmitriy starchukov@mail.ru Emperor Alexander I St. Petersburg State Transport University Soloviova 9046185117@mail.ru 56826013600 Peter the Great St. Petersburg Polytechnic University Gravit Marina marina.gravit@mail.ru

29 Politechnicheskaya St., St. Petersburg, 195251, Russia

The improving of the concrete quality in a monolithic clip The article deals with the possibility of increasing strength, hardness, frost resistance, water and corrosion resistance of concrete. The reduction of its abrasion resistance and water absorption by creating a layer of nonorganic monolithic high-strength clip on its surface is also considered. The possibility of synthesis of such clip by impregnating the concrete surface with a Sol of SiO2 is shown and thermodynamically substantiated. The mathematical dependence reflecting the strength of concrete in such a clip is developed. The distribution of efforts between the clip and not strengthened kernel in the case of load action is shown. The methods of X-ray, differential thermal analysis, electron microscopy and analysis of pore size were used for researching the phase composition and structure of the clip, as well as its porous structure. It was established experimentally the improvement of the various performance properties of concrete due to the presence of inorganic monolithic clip up to 200 %. Corrosion resistance of concrete in various aggressive environments is demonstrated and the concrete corrosion depth under the age of 50 years is calculated. 10.18720/MCE.80.1 сlip; silica Sol; heavy concrete; Gibbs free energy; surface energy; surface hardness; corrosion resistance https://engstroy.spbstu.ru/article/2018.80.1/ 01.pdf

RAR RUS 15-23 Peter the Great Saint Petersburg Polytechnic University Kirsanov Andrey kirsanov.ai@edu.spbstu.ru

Polytechnicheskay, 29

Peter the Great Saint Petersburg Polytechnic University Stolyarov Oleg oleg.stolyarov@rambler.ru

Polytechnicheskay, 29

Mechanical properties of synthetic fibers applied to concrete reinforcement Short synthetic fibers are increasingly used for reinforcing of cement-based composites along with metallic and inorganic fibers. In this work, the mechanical properties of short polypropylene fibers with different structures were investigated. The main characteristics, including tensile strength, Young’s modulus, strain at maximum load, and work of rupture were determined. In addition, fiber samples were examined for creep at various loading levels up to 50 % of the tensile strength. Relationship between the creep strain rate and applied stress for the fiber samples was determined. The results obtained can be used for selection the synthetic fibers for the reinforcement of cement-based composites. 10.18720/MCE.80.2 fiber reinforcement; polymeric fiber; creep; uni-axial strength; mechanical properties https://engstroy.spbstu.ru/article/2018.80.2/ 02.pdf

RAR RUS 24-36 Ufa State Petroleum Technological University Kozhaeva Ksenia st_kafedra@bk.ru Influence of the compensating device parameters on the underwater pipeline stability The definition of rational parameters of the developed compensating device of a triangular shape by calculation and experimental investigation methods is considered in the article. The proposed compensating device with the bent taps use has a more rigid design than the compensating device in the form of a broken bolt. Consequently, the correction coefficient of the compensator form, structurally executed with the use of bent taps is received by calculation and experimental methods for decreasing the longitudinal compressive force arising from the temperature drop to the ensuring level of the overall pipeline stability in the longitudinal direction, which allows to determine its rational parameters and is taken to be k = 0.85. The condition is obtained for determining the rational parameters of the proposed compensating device for underwater pipeline transitions in order to increase the overall stability in the longitudinal direction. In addition, the patented technology of laying the proposed compensating device is shown. 10.18720/MCE.80.3 experiment; compensating device; rational parameters; correction coefficient of the compensator form; ensuring the pipeline stability https://engstroy.spbstu.ru/article/2018.80.3/ 03.pdf

RAR RUS 37-47 Military Institute of rail transport troops and military communications Kalugin Yuri yuri_kalugin@inbox.ru Vilnius Gediminas Technical University Kaklauskas Arturas arturas.kaklauskas@vgtu.lt St. Petersburg State University of Architecture and Civil Engineering Kazakov Yuryi kazakov@spbgasu.ru Min-cut algorithm for network schedule by merging the vertices The task of reducing the total duration of the project ("compression", "crashing") occurs when developing and adjusting schedules. The activities requiring crashing are determined by the minimum of added resources at the unit reduction of the schedule. The minimum cut in a critical network determines such activities. The essence of searching the minimum cut by merging vertices (edge tightening) of the critical network is presented. The procedure of selecting vertices consists of the following. Possible merge options (tentative steps) are evaluated by equivalent cuts. The minimum cut will define priority vertex of a critical network. After this merging algorithm re-examines all the possible options of joining of adjacent vertices (on next step). The general applicability of the algorithm is demonstrated. Conditions of effective application of a method of the merge of vertexes are established. Search results of the minimum cuts of the critical network by means of this method are presented. Calculations have shown that in 14 of 15 examples the algorithm has established the global minimum cuts. Implementation of the proposed approaches will allow determining the activities to be optimized, calculate the size of reduction and the number of resources involved. The suggested methodology can be recommended for use by construction project managers. 10.18720/MCE.80.4 civil engineering; construction management; project scheduling; critical path method; crashing; minimum cut problem https://engstroy.spbstu.ru/article/2018.80.4/ 04.pdf

RAR RUS 48-61 Peter the Great Saint Petersburg Polytechnic University Atavin Ilya ilya_region51@mail.ru

Polytechnicheskay, 29

6701751705 0000-0002-7889-1996 Peter the Great Saint Petersburg Polytechnic University Boris Melnikov kafedra@ksm.spbstu.ru

Polytechnicheskay, 29

Dresden University of Technology Semenov Artem Semenov.Artem@googlemail.com Chernysheva Nataliia Peter the Great Saint Petersburg Polytechnic University Yakovleva Elena helena47@mail.ru

Polytechnicheskay, 29

Influence of stiffness of node on stability and strength of thin-walled structure The article is devoted to the evaluation of the torsional stiffness of the beam-pillar nodal connection of thin-walled rack structures. Results of in-place testing of several girder rack models are described, beam model and combined one are considered. Computational finite element (FE) models of these racks are designed to develop a FE analysis by software complex ANSYS. Assessment of the torsional stiffness of the beam-pillar nodal connection in these structures is obtained by comparison of results of computation and experimental ones. Critical buckling load for the first buckling mode is determined both experimentally and computationally. Buckling modes of “out of the face plate” and “in the face plate” are considered. The influence of the torsional stiffness of the beam-pillar nodal connection on bearing capacity and buckling stability of thin-walled rack structure is investigated. Correspondence of these characteristics and number of tiers is revealed. 10.18720/MCE.80.5 light steel thin-walled structure; torsional stiffness; finite element method (FEM); girder rack; beam; pillar; tier; buckling; critical load https://engstroy.spbstu.ru/article/2018.80.5/ 05.pdf

RAR RUS 62-72 Center of Engineering Services and Technical Expertise Emelianov Denis snegiri_emelianov@mail.ru National Research Moscow State Civil Engineering University Tusnina Valentina valmalaz@mail.ru The seismic stability of facade system with facing by composite panels The hinged ventilated facades installing is a perspective technology of buildings decoration. Suspended facade systems are widely used for construction and reconstruction of residential, administrative, public and industrial buildings. Using suspended facade systems for decorating exterior walls is helping designers to solve the problems of thermal protection and architectural and artistic expressiveness of buildings by using modern heat-insulating and decoration materials. The finishing of facades with composite panels is especially effective for buildings erected in areas with seismic activity because the using of lightweight cladding leads to a significant reduction in the mass of external walls and to the reduction of seismic loads. In this article we present the results of the experimental study of bearing capacity and operational reliability under dynamic loads of hinged facade system with toothed nodal fastening of aluminum composite panels, which was developed in the Moscow State Construction University. The tests were conducted on a vibrating platform of a pendulum type by a vibrational (resonant) method, which allows to determine the power load simulating seismic actions in a wide range of frequencies, in the Central Research Institute of Building Constructions named after V.A. Kucherenko (CRIBC). The results of experimental studies clearly demonstrated the increased seismic stability of the structure with toothed nodal fastening of composite panels in comparison with facade systems having a similar type of cladding. We found out that the developed design is able to dissipate the energy from the dynamic load due to the presence of additional connections in the structural solution of the tooth assemblies and allow to quench the energy of the oscillation of the system under seismic influences. 10.18720/MCE.80.6 suspended facade system; composite cladding panels; notched hub mounting; seismic resistance; dynamic load; vibration platform; acceleration https://engstroy.spbstu.ru/article/2018.80.6/ 06.pdf

RAR RUS 73-80 Southwest State University Kolchunov Vitaly asiorel@mail.ru Southwest State University Savin Sergey suwin@yandex.ru Survivability criteria for reinforced concrete frame at loss of stability Analysis of scientific publications on the assessment of resistance of structures to progressive collapse, as well as existing and projects of design codes of different countries, in particular the project of Design Code "Protection of buildings and structures against progressive collapse. The design requirements. General conclusions", shows, that the main evaluating criteria are strength parameters. At the same time, structures, which are made of high– strength materials and have small sizes of cross-sections, as well as structures operating in aggressive conditions, when the cross-section decrease or the computational length suddenly increase, should be checked to the loss of stability of the bearing elements. The purpose of this study is to obtain the evaluating criteria of the survivability and residual life of reinforced concrete (RC) structural systems at sudden loss of stability of the element, caused by the evolutionary accumulation of a critical level of corrosion damage. The article presents analytical dependences to determine the critical value of the cross-section stiffness of the corrosively damaged element and the critical time, after which the structural system lose stability in conditions of simultaneous action of forces and aggressive environmental influences. Proposals are given to assign the survivability parameters of reinforced concrete structural systems, operating under exceeding limit states, that caused by the sudden loss of stability of the carrier element at the accumulation of critical value of corrosion damages. 10.18720/MCE.80.7 survivability; stability; multi-storey frame; reinforced concrete; corrosion damage https://engstroy.spbstu.ru/article/2018.80.7/ 07.pdf

RAR RUS 81-94 6506030356 0000-0001-6744-9249 Tampere University Garifullin Marsel marsel.garifullin@tut.fi

Kalevantie 4, FI-33100, Tampere, Finland

Peter the Great Saint Petersburg Polytechnic University Bronzova Maria bronzochka@mail.ru

Polytechnicheskay, 29

Tampere University of Technology Heinisuo Markku markku.heinisuo@tut.fi

Tampere, Finland

Mela Kristo kristo.mela@tut.fi Tampere University of Technology Pajunen Sami sami.pajunen@tut.fi Cold-formed RHS T joints with initial geometrical imperfections Generally, numerical simulations of structures are carried out in such a way as to most accurately repeat their real behavior. The current rules for finite element modeling of tubular joints oblige scientists and engineers to construct their numerical models considering initial imperfections. However, not all joints are sensitive to initial imperfections. Often consideration of initial imperfections brings no reasonable improvements in the accuracy of results, but severely complicates numerical simulations. In such cases, the effect of geometrical imperfections can be effectively replaced by a simple theoretical equation or neglected entirely. This paper evaluates the effect of initial geometrical imperfections on the structural behavior of cold-formed rectangular hollow section T joints. Imperfections are simulated using the conventional approach for thin-walled structures, applying corresponding buckling modes to the perfect geometry. The paper analyzes several buckling modes and their combinations to identify the most rational technique for simulation of imperfections under in-plane bending and axial loading. Based on the obtained results, parametric studies are conducted to investigate the effect of initial imperfections on joints with various geometry and material properties. The results demonstrate that initial imperfections reduce the resistance and initial stiffness of joints. However, the observed effect has been found sufficiently small to be safely ignored in computational analyses. 10.18720/MCE.80.8 hollow section joint; resistance; initial stiffness; finite element analysis; imperfection https://engstroy.spbstu.ru/article/2018.80.8/ 08.pdf

RAR RUS 95-103 0000-0002-4577-8794 Petersburg State Transport University Belash Tatiana belashta@mail.ru Petersburg State Transport University Yakovlev Anton anton.yakovlev.94@mail.ru Seismic stability of a tsunami-resistant residential buildings We have analyzed data on the mechanism of tsunami waves formation and destruction caused by thereby, and also have summarized recommendations on tsunami-resistant construction. For reduction of damage and loss from strong earthquakes and high tsunami waves, hereon the solution for tsunami protection of the construction area is proposed in which small typical residential buildings are located in the upper part of the motor road trestle. At such solution, residential buildings are “torn off” from the earth surface on considerable height, and, as result, are not exposed to tsunami wave impact. By using the computerized complex SCAD 21.1, four options of the proposed tsunami-protection solutions have been analyzed. In the course of such analysis, the optimal option – from the point of view of seismic stability – has been selected. For this option, we have checked sections of elements for arising forces, and also made necessary corrections in structures. Final proposed option of the structure provides high seismic and tsunami safety. 10.18720/MCE.80.9 tsunami; tsunami resistance; tsunami protection; seismic stability; build https://engstroy.spbstu.ru/article/2018.80.9/ 09.pdf

RAR RUS 104-118 Peter the Great St. Petersburg Polytechnic University Zaborova Daria

St. Petersburg, Russia

Peter the Great St. Petersburg Polytechnic University Strelets Kseniya kstrelets@mail.ru

29 Politechnicheskaya St., St. Petersburg, 195251, Russia

Peter the Great Saint Petersburg Polytechnic University Bonivento Bruges Jose ing.joseboniventob@gmail.com

Polytechnicheskay, 29

Peter the Great Saint Petersburg Polytechnic University Asylgaraeva Margarita margarita.asylgaraeva@yandex.ru

Polytechnicheskay, 29

University of Sao Paolo de Andrade Romero Marcelo marcelo_romero@icloud.com Berlin Institute of Technology Steffan Claus claus.steffan@tu-berlin.de Engineering solutions for the social housing, integrated into urban environment Deprived areas integrated into actively developing environment of the modern cities is a burning issue which is being studied in megalopolises of Latin America, Africa and Asia. Diverse controversial issues emerge in the interaction between the city community and inhabitants of the favela. The article deals with the solution for this issue based on the example of interaction between Brazilian favela “Sao Remo” and the University campus of Sao Paulo. Nowadays, this University conducts constant social research to find a suitable integration between both sides of the wall. One of this initiatives was raised in the symposium WC2-2017 which purpose was to elaborate the solution for a social infrastructure to be designed to improve links. Moreover, this infrastructure is sustainable in order to mitigate social, environmental and economic impacts. After an analysis of diverse design strategies, the outcomes were obtained in regard to some technical alternatives which implementation depends on stakeholders’ wiliness to collaborate and understanding to what extent they are ready for compromise. 10.18720/MCE.80.10 civil engineering; sustainable development; infrastructure; energy-efficiency; favela; environment; USP https://engstroy.spbstu.ru/article/2018.80.10/ 10.pdf

RAR RUS 119-127 Peter the Great Saint Petersburg Polytechnic University Statsenko Elena staclena@mail.ru

Polytechnicheskay, 29

Peter the Great Saint Petersburg Polytechnic University Ostrovaia Anastasiia stasya2609@yandex.ru

Polytechnicheskay, 29

Peter the Great St. Petersburg Polytechnic University Olshevskiy Vyacheslav 79119199526@yandex.ru

29 Politechnicheskaya St., St. Petersburg, 195251, Russia

56426211200 0000-0002-3541-0072 Peter the Great Saint Petersburg Polytechnic University Petrichenko Mikhail fonpetrich@mail.ru

Polytechnicheskay, 29

Temperature and velocity conditions in vertical channel of ventilated facade The most economically viable and practicable method of moisture removal from the air gap with the help of free convective air flows are presented in the article. An experiment conducted on a laboratory bench simulating a hinged ventilated facade is described. The parameters and design features of a particular building envelope are determined. Also, the impact of technological gaps – grooved lines is described, which influence the air velocity in the ventilated channel, which in turn affects the temperature and humidity conditions of the building envelope. The experimental evaluation of air velocity and air temperature along the height of ventilated layer is provided in the article. The impact of grooved lines density and the method of hot plane heating on the distribution of air temperature and velocity. Optimal is the construction which is designed with the least number of rusts, from the technological point of view. 10.18720/MCE.80.11 ventilated facades; convective air flows; grooved lines; air velocity; air temperature; facing layer; air gap https://engstroy.spbstu.ru/article/2018.80.11/ 11.pdf

RAR RUS 128-137 National Research Moscow State Civil Engineering University Tamrazyan Ashot tamrazian@mail.ru National Research Moscow State Civil Engineering University Lushnikova Valeria N_A_T_E_L_K_A@mail.ru The effect of reinforcement corrosion on the adhesion between reinforcement and concrete Due to aggressive environmental conditions, the adhesion between reinforcement and concrete deteriorates. This factor has a significant influence on the safety and efficiency of buildings and structures. The strength of adhesion between reinforcement and concrete decreases in the process of corrosion, and therefore requires a longer anchoring length of the reinforcement. The longer the anchoring length, the greater the guarantee that the destruction of the reinforcement in concrete does not occur until the lifetime of the reinforced concrete elements is expired. Various parameters affecting the reinforcement adhesion strength in reinforced concrete elements are considered. The ratio of the thickness of the protective layer and the diameter of the reinforcement (c/ds) affects the adhesion strength. With a higher (c/ds) ratio the loss of the adhesion strength is less than with a lower (c/ds) ratio. The mass loss of the reinforcement is an important parameter, and it can determine the level of corrosion. This value can be used for the development of the correlation between corrosion, cracking, the adhesion and ultimate strength of reinforced concrete elements. 10.18720/MCE.80.12 corrosion; mass loss; adhesion strength; anchoring https://engstroy.spbstu.ru/article/2018.80.12/ 12.pdf

RAR RUS 138-150 St. Petersburg State University of Architecture and Civil Engineering Ivanov Andrei andreyivanov4@gmail.com Chernogorskiy Sergey St. Petersburg State University of Architecture and Civil Engineering Vlasov Mark markvlasov@mail.ru Seismic design optimization considering base-isolation system Structural seismic design optimization researches reviewing shows that existing economic effect assessment methods take into account only traditional seismic retrofit schemes excluding baseisolation system employment. The purpose of this study is to obtain economic optimization which allows to compare the economic effect E of base-isolated structure among with traditional seismic retrofit schemes. Here the approach is proposed of earthquake caused damage state Drel computation in base-isolated structure considering repair works with due regard to its life-cycle N. The example of damage state Drel evaluation for base-isolated and traditional retrofitted structures is performed considering different seismic intensities. It is shown how the value of damage state proceeds according to the building life-cycle N in each case. The economic effect E for these cases is estimated with the aid of proposed optimization algorithm. 10.18720/MCE.80.13 optimization procedure; earthquake engineering; structural damage; seismic base isolation; nonlinear static pushover analysis; averaged response spectrum; capacity curve; economic effect; life-cycle https://engstroy.spbstu.ru/article/2018.80.13/ 13.pdf

RAR RUS 151-170 57196066346 0000-0002-8051-5914 National Research Moscow State Civil Engineering University Denisov Aleksandr den-al-v@inbox.ru

Moscow, Russia

Riga Technical University Sprince Andina andina.sprince@rtu.lv Analytical determination of thermal expansion of rocks and concrete aggregates The article provides selection and approbation of the model and the model-based method for the analytical determination of thermal expansion and rock fracturing (decompression) and concrete mineral aggregates according to the data about thermal deformations of minerals based on information of the mineral composition, the average grain fineness of minerals and the elasticity modulus of rock. To accomplish the research, the author has used two models available in scientific publications: 1. Balashov and Zaraisky Model for calculating the thermal expansion and decompression of rock based on thermal deformations of minerals. The model does not take into account the structure and mechanical properties of rock. 2. The model of Denisov (one of the authors of this work) and Dubrovskiy was developed and evaluated earlier for the analytical determination of radiation expansion and rock fracturing when neutrons are irradiated by nuclear reactors on the basis of radiation deformation of minerals. The model takes into account the grain fineness and elasticity modulus of rock. The model is accepted for research on the basis of the analogy between the processes of thermal and radiation changes of rock at the level of interaction in mineral crystals. The approbation was done on the basis of both the information available in the scientific publications and experimental data obtained in this work which have shown thermal expansion of 22 in magmatic and sedimentary rock in the range from 20 to 700 °C. It has been determined that the model of Denisov and Dubrovskiy especially with correction introduction associated with the increase in the rock plasticity when heated is adequate and better than the Balashov and Zaraisky Model which describes the process of thermal expansion and rock fracturing. This model can be used for the analytical determination of thermal expansion and isotropic rock fracturing and concrete mineral aggregates at temperatures up to 700 °C (the most reliable – up to 500 °C) at normal pressure and humidity with the absence of included minerals that provide water and gases emission when heated. 10.18720/MCE.80.14 thermal expansion and fracturing; analytical determination; rocks; concrete mineral aggregates https://engstroy.spbstu.ru/article/2018.80.14/ 14.pdf

RAR RUS 171-180 Peter the Great St. Petersburg Polytechnic University Titkov Vasiliy titkovprof@yandex.ru

29 Politechnicheskaya St., St. Petersburg, 195251, Russia

Kazakh National Technical University named after K.I. Satpayev Munsyzbai Toleuhan toleuhan_aidar@mail.ru Bekbaev Amankeldy Kazakh National Technical University named after K.I. Satpayev Shakenov Kalizhan kalizhan-90@mail.ru Construction of autonomous buildings with wind power plants The use of renewable energy converters, including local wind power plants to provide private households and houses with electricity, is gaining popularity, especially in countries where there are appropriate state subsidies. In this paper considered approach to the use of the building roof in the conversion of the kinetic energy of the incoming wind into electrical energy by a closed wind power plant (WPP). The construction of the WPP and the roof are converted into a finite element model for aerodynamic calculations. The model of WPPs and roofs is investigated by changing the angle of attack of the roof, with different roofing applications, and also some other elements of the WPP design in order to find the most optimal conditions for increasing the energy efficiency factor (EEF) of the energy carrier. The described approach with the use of a roof in the conversion of wind energy into electrical energy can be used in the structural design and construction of autonomous houses and buildings. 10.18720/MCE.80.15 wind energy; wind power plants; increase in energy efficiency factor; efficient converters; buildings; structural design; construction; renewable resource; energy efficiency https://engstroy.spbstu.ru/article/2018.80.15/ 15.pdf

RAR RUS 181-194 Kabardino-Balkar State University named after H.M. Berbekov Hezhev Tolya hejev_tolya@mail.ru Kabardino-Balkar State University named after H.M. Berbekov Zhurtov Artur zhurtovartur@mail.ru Kabardino-Balkar State University named after H.M. Berbekov Tsipinov Ayes czi.ayes69@yandex.ru Belgorod State Technological University named after V.G. Shukhov Klyuev Sergey Klyuyev@yandex.ru Fire resistant fibre reinforced vermiculite concrete with volcanic application The results of studies on the development of vermiculite concrete composites with application of volcanic ash and pumice are presented. The composition of cement fibre vermiculite concrete fire resistant composites is offered, which allows reducing the consumption of Portland cement and simultaneously increasing their flame retardant properties. The use of basalt fibers in composites can improve the strength, fracture toughness and fire retardant properties of the coating due to the perception of tensile thermal stresses during the fire. Replacement of cement up to 30 % by weight with volcanic pumice fraction d < 0.16 mm significantly improves heat-resisting properties of cement stone with a simultaneous increase in flexural strength and no significant loss of compressive strength. Experimental and theoretical studies of fire resistance of double-layer ferroconcrete constructions showed high fire resistant properties of the developed cement fibre vermiculite concrete fire resistant composites. The algorithm for calculating the fire resistance of multi-layered building constructions with finite-difference implicit scheme for solving the heat conduction problem and the sweep method, providing reasonable agreement with experimental data is offered. 10.18720/MCE.80.16 vermiculite fly ash pumice fibre vermiculite concrete composite ferrocement fire-resistance https://engstroy.spbstu.ru/article/2018.80.16/ 16.pdf

RAR RUS 195-203 National polytechnic university of Armenia Soghomonyan Vardan stakyan.mihran@yandex.ru National polytechnic university of Armenia Chibukhchyan Grigor armenpack@mail.ru National polytechnic university of Armenia Chibukhchyan Oganes hovhannesch@gmail.com Diagnostics of fatigue fractures of building structures elements The article deals with the issues of increasing the fatigue strength of critical parts and components of construction machines and equipment, which are more often subjected to fatigue failure under the influence of variable complex loading. A quantitative estimate of the size of the fatigue fracture zones in the parts and joints installed in the building structures and power circuits of this construction equipment has been made. A new technique for technical diagnostics of the causes of fatigue destruction of knots of construction machines and structures is considered, revealing regularities of changes in microhardness in various zones of fatigue fractures. The results of measurements of microhardness in the zones of fatigue fractures are obtained. The systems of standard regression equations are obtained that allow one to quantify the parameters of the loading regime that led to destruction. A computational subroutine has been created that allows us to obtain analogous equations by processing the microhardness measurements of the fracture under study, and comparing them with the reference equations, give a reasonable quantitative conclusion on the causes of failure. 10.18720/MCE.80.17 building structures; construction equipment; fatigue fracture; fractography; technical expertise diagnostics https://engstroy.spbstu.ru/article/2018.80.17/ 17.pdf