«Transport construction» Magazine

№ 2 on 2023:

Reliability and accessibility of the north of the Far East as a factor in the development of Russia's unified transport system

Pereselenkov G.S.

Abstract:
The paper considers the prospects of development of the integrated transport-port system in the northern Far East by stage-by-stage design and route variant selection of the prospective network, with completion of works at each stage according to the "time" as an efficiency criterion. The extensive experience in development of the transport network of Western and Eastern Siberia and application of the reliability theory in assignment of the transport security of territories for further placement of the national economy objects are also taken into account.

Keywords:
north of the Far East, prospective route, railway, transport availability, transport network, transport service reliability

Relevance and prospects for the development of the method of reinforcing girder reinforced concrete bridges with an overhead slab

Anisimov A.V., Kovalenko N.A., Gurchev A.V.

Abstract:
A review of the practice of reinforcing and widening girder spans of road bridges is presented; the advantages and prospects of using extra strong fibre concrete for the overhead slab arrangement are considered.

Keywords:
bridge structures, calculation methodology, heavy-duty fibre concrete, load class, overhead slab, span reinforcement

Improvement of the methodology for determining the load bearing capacity of bridge abutment of railway bridges Shvets Y.A.

Abstract:
The paper presents the results of research into the improvement of the methodology of determining the load bearing capacity of bridge abutment of railway bridges, including those operated on the permafrost foundations and built according to Principle I, which enables to establish rather reliably the actual class of a structure. The solution of the problem includes development and substantiation of the rule for complex (non-rectangular) influence lines loading for pillars of frameless abutments by introduction of distortion coefficient.

Keywords:
bridges, complex influence lines loading, influence lines distortion factor, load capacity

Arrangement of sprayed polymer waterproofing for repair of bridge structures

Kamenskikh A.N., Kochetkov A.V., Valiev Sh.N., Chizhikov I.A.

Abstract:
The mechanism of integrity failure in the layer of waterproofing of bridge structures on the slope of the protrusion of macro-roughness is established. The formation of caverns is related to the temperature and flow rate of the spraying mixture, cooling time, as well as the width and height of the macro-roughness overhang. It has been found experimentally that intensive cavern formation occurs at a waterproofing layer thickness up to 1.1 mm; spot cavern formation occurs on the slopes of areas with maximum roughness (the greatest depth of the depression relative to the adjacent ledge).

Keywords:
bridge structures, cavern formation, driveway, heating, macro roughness, spraying, technical standardisation, thermal imaging, waterproofing

Evaluation of metal insulation efficiency for tunnel lining reinforcement

Merkin V.E., Ustinov D.V., Khokhlov I.N.

Abstract:
The topical problem of modern tunnel-building - reinforcement of bearing structures in the presence of defects or insufficient carrying capacity - is considered. Various methods of strengthening the newly-built and repaired tunnels from the point of view of their technical and economic efficiency are analysed by means of numerical modelling in spatial problem statement and on the basis of practical experience. It is shown that utilization of 8-10 mm thick steel plate inner lining (metal insulation) for strengthening leads to insignificant (about 10 %) increase of lining safety factor at relatively high cost in comparison with other methods and considerable decrease of its repairability. As an alternative variant of strengthening the rigid base of a track in a tunnel is proposed to carry out in the form of reinforced concrete longitudinal stiffening beam which parameters are determined by calculation.

Keywords:
efficiency, flume blocks, lining, load-carrying capacity, metal insulation, reliability, reinforcement, stiffening beam, subways, tunnel

Choice of optimal finite element mesh in investigation of stress-strain state of transport tunnels

Novak Yu.V., Shevchenko A.A, Bautdinov D.T.

Abstract:
The problem of selection of optimal mesh of such elements which often arises in calculations of stress-strain state of tunnels with application of finite element method is considered. The research is carried out on the example of an elastic isotropic medium under flat deformation weakened by a circular hole and experiencing compression from a distributed vertical load (Kirsch problem with exact analytical solution). An optimal finite-element mesh for the parametric analysis of the tunnel stressed state in the ANSYS software package which may be adopted for further investigations of circular-section underground structures has been selected and found to be close enough to the analytical solution.

Keywords:
elastic medium, finite element dimensions, finite element method, finite element type, Kirsch problem, test verification problem

Influence of asphalt granulate and deflagmators on mobility of cast asphalt concrete mixtures

Kozikov I.O., Lupanov A.P., Silkin V.V., Sukhanov A.S.

Abstract:
The results of experimental studies of the cooling process of cast asphalt concrete mixtures are presented. According to the results of the performed studies, it was found that the introduction of the Sasobit additive together with asphalt granulate increases the mobility of cast mixtures while ensuring its workability, reducing the temperature by 20 °C compared to the mixture without additives.

Keywords:
asphalt granulate, cast asphalt concrete, cast asphalt concrete mixtures, deflegmators, mobility of the cast mixture

Area of applications for single-component hydroactive polyurethane foams and gels in underground construction

Kobidze T.E., Krymov O.B., Konyukhov D.S., Slabodkin A.A., Arnold Heinrich

Abstract:
On the basis of analysis of chemical reaction products properties of one- and two-component polyurethane systems, information from scientific and technical literature as well as requirements of domestic and foreign normative documentation the necessity of distribution of purpose and application field of injectable hydroactive one-component polyurethane systems (foams and gels) and two-component polyurethane resins for repair of underground constructions of underground has been substantiated.

Keywords:
foam, gel, hydroactivity, hydrolysis, injection, macromolecule, polyurea, polyurethane

Structural and logical bases of calculation reliability of the crushing and screening machines producing lines for the cub-form crushed stone production in Tajikistan

Shtephan Y.V., Abdullayev A.R.

Abstract:
Structural and logical schemes of the reliability of the technological line have been compiled. A method for expanding the commodity nomenclature of produced crushed stone fractions for asphalt concrete of the upper layers of road surfaces is proposed. Calculation of the reliability, productivity and main parameters of crush stone production line in Tajikistan is carried out.

Keywords:
crushing and screening equipment, machine reliability, road-building stone materials, stone rubble production

Makovsky L.V., Kravchenko V.V.

Abstract:
The emergency situations in the tunnels under construction, caused by fires and ignitions, are considered. The causes of such situations, their consequences and methods of liquidation are analysed. Examples are given from the practice of domestic and foreign tone-building, demonstrating the most characteristic manifestations of fires and fires. This applies to the tunnels of the Moscow, St. Petersburg, Tbilisi, Dnepr and Kyiv metros, as well as the largest mountain tunnels along the Baikal-Amur Mainline. From foreign practice, accidents in tunnels under construction in Great Britain, Denmark, Germany, the USA and Australia are considered. The most effective measures to prevent fires and ignitions in tunnels under construction are outlined. The need for scientific research to correct existing and create new regulatory documents regulating measures to prevent possible accidents, and in case of their occurrence, to eliminate the consequences, is indicated.