Piezoceramics based on the lead zirconate-titanate (PZT) system is the basis of most transducers operating on the piezoelectric effect and are used in various electronic devices operating in the sections of electrical and hydroacoustics, ultrasonic technology, etc. In turn, piezoceramic materials created in the last century have substantially exhausted their potential for use in modern devices, and it is rather difficult to develop new compositions and is not economically efficient. In connection with the above, an urgent task is to find modern ways to increase the parameters of piezoceramic materials.
Keywords: piezoceramics, piezophase, piezomaterial, ceramic technology, microstructure
The article deals with the problem of imperfect design of modern bridge structures in Russia, using the example of comparing different forms of a continuous profile of bridges. Examples are given where the use of a curvilinear form would save space on the construction of bridges. A number of calculations and their analysis were carried out, as a result of which we received that the parabolic shape of the longitudinal profile of the bridge is the most efficient and economical
Keywords: construction, bridge, longitudinal profile, slope of the embankment, efficiency, efficiency, transverse profile of the embankment, length, volume
The article deals with the problem of pedestrian crossings and congestion of highways of the city of Volgograd. It described the situation on the highways and solutions to eliminate congestion on the road. Car traffic was conditionally divided into 3 categories: transit, the transit from the center and the car flow moving into the center. Studied the question of the safety of pedestrians on the road, because, except for pedestrians with the intersection increases their safety. The study and analysis of all previously implemented measures was proposed construction of underground pedestrian tunnels. Several embodiments of tunnel junctions have been considered. Analysis of the current transport situation revealed the busiest places in the city center.It was noted that the construction of underpasses solve the problem of vehicular traffic in the city center and pedestrian safety, and the city will have new underground space.
Keywords: Сar flow,highway, tunnel transition, transit transport, carriageway, longitudinal,security,road traffic
The article analyzes the natural conditions of the Northern latitudes of Russia, where the main reserves of fossil hydrocarbons and metals are concentrated. It is shown that mining requires the development of the road network and artificial structures on the roads. It is noted that the most difficult stage in the construction of bridge structures is the construction of foundations. The types used in the Northern latitudes of foundations are considered, and their positive and negative qualities, such as weight, method of construction and volume of earthworks, are noted. The paper emphasizes the relevance of the problem of maintaining the stability of permafrost soils in seasonal thawing and loss of their bearing capacity. Methods of maintaining the soil in a solid state can be natural and artificial. The methods of thermal stabilization of soils, as well as machinery and equipment used in these conditions.
Keywords: permafrost, road network, bridge, polystyrene, superstructure, pile support, Foundation, thermal insulation screen, heat stabilizer
The article deals with the problem of the functional state of the bridge park in Russia. The statistics of the number of bridges, newly built bridges. Attention is focused on the inconsistency of old bridges with modern regulatory requirements for safety, carrying capacity, and carrying capacity. Noted on the relevance of flood impact on bridges and roads. The causes of occurrence are described. The problem of flood forecasting is highlighted. Examples of accidents of bridge structures from the effects of water flow are given: sediment, roll of supports and abutments, erosion of the embankment approach. Based on the situation in the city of Chita, the statistics of the frequency of flooding in different years are given, the critical levels of these disasters are indicated, and statistics on the consequences of the impact of the flood is given. The impact of the normative water flow is considered, and it is proposed to analyze the effect of the excess flow arising from the maximum level of bottling. Presents the results of calculations for which comparisons are made of various approaches to determine the depth of erosion of the channel.
Keywords: bridges, flood impact, safety, bridge destruction, regulatory documents, erosion depth, water flow
This article is dedicated to one of the symbols of Volgograd city, which is the Astrakhanskiy Bridge. We described the history of creation and the technical specifications of the bridge over the Tsaritsa river. After conducting an investigation, some defects in the bridge construction were uncovered. The framework arcs have longitudinal cracks, the protective layer of concrete is destroyed; the longitudinal main reinforcement is exposed and corroded. The protective layer of concrete was removed and the longitudinal main reinforcement was corroded on the longitudinal beams. During operation of the bridge, the defects that decrease load capacity and durability appeared: destruction of the protective layer of concrete on a plate of about 2 square meters. This led to the beginning of corrosion of the lower reinforcement net. Steel brackets, holding the walkway slabs, are heavily corroded; the protective paint coating on them is destroyed over significant lengths. The analysis of detected damage allowed to evaluate their impact on the durability and load capacity of the construction and determine those, who are responsible for its occurrence. It is noted that postponing of repair operations has a negative impact on the state of the bridge.
Keywords: bridge, city symbol, superstructure, roadway plate, defects, arch, bridge system, bearing structures, durability, load capacity
The article deals with the design of bimetallic bridges, their advantages in comparison with reinforced concrete bridges. Its given the characteristics and chemical composition of conventional bridged steel and high strength steels. The scheme of dividing continuous lash of span structure into spans is considered and the ratio of spans with equal bending moments is calculated. Its given the calculation of an effective three-span system. The existing efforts and bimetallic standard blocks of three types are proposed for them. Blocks are made of two types of steel: conventional cross section of bridge steel, heavily loaded cross section of structural high tensile. In block A, the lower belt; in block B the lower belt, the wall and thongs of the orthotropic plate; in block K the lower belt and the beam wall is made of strong steel. Such unification will significantly reduce labor intensity and weight of the structure.
Keywords: bimetallic, span structure,steel grade,enveloping the diagram, normal stresses, mounting block, sheet hire
In this article we consider correspondence problem of the supporting parts containing deformable polymers used in the beam bridges (used in bridge constructing - лишнее, мне кажется). According to the shear diagram, supporting parts shall provide free angular and linear displacements of the beams' end faces sections. Otherwise gradual destruction of the nearby areas is possible. We study a rubber supporting part (RSP). Factors contributing to the deformation of the supporting part and their calculation with different algorithms, including the differential equation of the curved axis and Mohr method are given. The values of angular and linear deformations for the concrete reinforced bridge beam are calculated.
Keywords: bearing, adjustable bearing, deformation, bridges, bridge beam, shear strains, angular displacement, linear displacement, crumple.
Issues related to the safe operation of the transport system as a whole. The article touches upon the questions on how to repair the car in Volgograd. In the city, this guide is the only link in the area. Long-term operation of the overpass led to the accumulation of a large number of defects and damages that prevented it from being fully used. Accounting for all aspects of the safe use of the way to ensure its sustainable functioning. The measures ensuring the safe operation of transport facilities include: increasing the dimensions of the roadway of the overpass, strengthening structures to increase the carrying capacity to normative work, processing and storing seismic precipitation on the span, installing a video camera for rapid response in case of traffic accidents and illegal actions. To increase the load-bearing structures, the new beams should be replaced with new beams, designed for high loads, and also use composite reinforcement with carbon fiber.
Keywords: safety, load-carrying capacity, reconstruction, bridges, sustainable functioning, reinforcement, diagnostics of structures, waterproofing
In the article the main types of corrosion of concrete, such as chloride, sulfate, acid and carbon dioxide, are considered, the mechanism of cement stone damage is given. The danger of leaching of concrete is shown. Protection of bridges from penetration of aggressive moisture is waterproofing. Materials used for the device of waterproofing in our country are given, their advantages and disadvantages.
Keywords: Waterproofing bridges, carbon dioxide corrosion, chloride corrosion, acid corrosion, concrete leaching, waterproofing materials, adhesion
One of the most important elements of the bridge, from which the service life of this structure directly depends, is the supporting part. It provides the movement and rotation of span structures, as well as the transfer of all loads from the forces acting on them to the supports. The task of the designer is to select such support parts, that could be allowed maximum reducing of the forces, acting at the ends of the beams and having a minimum resistance to their free movement. It is necessary in each case to select the support part, which will most closely meet the requirements. To solve this problem, the author structured and tabulated the kinds of support parts. And also an analysis of the main characteristics of some of them.
Keywords: bearing part, exothermia, bridge structure, durability, service life, transfer of loads and displacements, deforming systems, sliding systems, rolling systems
Currently, counterfeit goods began dating in all types of consumer goods. The sector of textile products is one of the most susceptible to counterfeiting. A lot of companies confronted with the problem of counterfeiting of their products on a commercial scale. One of the promising directions in the area of protection against counterfeiting of products is the use of RFID technology. On the basis of one of the basic RFID standards established technology NFC, electronics manufacturers inserted into the smartphones the corresponding module. Using NFC technology, together with the developed system for the identification of products can serve as additional, and for some companies and the only protection against forgery.Each item in the system has a unique QR-code link to the page containing detailed information. Link consists of a website address and a unique identifier. The resulting QR-code may be printed on the label of the product, which is integrated with the NFC tag containing the same unique identifier. QR-code reading is carried out by appropriate application. NFC tag reading is possible if the corresponding module, which is now present in most mobile devices. The owner of a mobile device, comparing the received code, be able to distinguish original products from counterfeits.
Keywords: counterfeit goods, RFID technology, two-dimensional coding, QR-code