Influence of natural aging on the behavior of strength and deformation properties of concrete along the cross-section of structural elements

The need for special saving devices arises during emergency response. Such situations are connected with rescuing of people or animals from deep narrow holes or even from under blockages of constructions. By using the saving devices the cargo raising on a certain height is possible if other ways of delivery are absent. Main structural elements of saving devices are three rod pillars. Top ends of rods are connected in a mounting knot. Often the saving device is equipped with the winch. The winch could be fasten to one of the rod pillars or have individual placing. Rescuing devices differ in a type of a rod design (straight or a slopy plane), loading capacity, rods production material, type of rods connection, a possibility of using on slopes with pillars location in the different planes, modifications of winches, compactness during transportation. There is a big variety of rescuing devices, however in the market of Ukraine offer mostly straight rod rescuing devices. Therefore there is a need for creation of design and durability checking of the slopy rod rescuing device which could be applied to carrying out rescue operations from bridges, buildings and other constructions. In this work it is performed an estimation of durability of a design of the slopy rod rescuing device. It is considered three cases of the support pillars placement. The first case is when pillars of the slopy rescuing device are placed in one horizontal plane. The second case - the longest rod pillar is placed on a ledge. The third case - two shorter rod pillars are placed on a ledge. For each of these cases it is established a type of deformation of rods of the saving device. Construction rods are stretching or compression during work are and loaded with longitudinal forces. From the stretching durability condition the cross section of steel rods is picked up.

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Development of effective fiber-reinforced concrete compositions used in transportation structures

Eastern-European Journal of Enterprise Technologies ◽

10.15587/1729-4061.2021.227139 ◽

2021 ◽

Vol 2 (1 (110)) ◽

pp. 6-11

Author(s):

Nizami Ahmadov ◽

Irade Shirinzade

Keyword(s):

Reinforced Concrete ◽

Cross Section ◽

Oil And Gas ◽

Fiber Reinforced Concrete ◽

Fiber Reinforced ◽

Operational Parameters ◽

Deformation Properties ◽

The Cross ◽

Effective Reinforcement ◽

Concrete Matrix

The possibility of producing fiber-reinforced concrete with high deformation properties by regulating the microstructure and using it in the design of transport structures was considered. It was found that to create high-performance transport structures, it is necessary to modify fiber mixtures with complex additives, i. e. increase the strength of fiber-reinforced concrete at the micro-level. To obtain a denser structure of the concrete matrix, complex additives were used – ultrafine additive (silica fume) and Master Air 200 B air-entraining additive. It was experimentally proved that using such additives reduces the water-cement ratio and further strengthens the concrete matrix structure. The design of the unloading structure on the railway line constructed from the Karadag station (Republic of Azerbaijan) to the SOCAR oil and gas processing and petrochemical complex using fiber-reinforced concrete modified with complex additives was made. The results of designing the fiber-reinforced concrete unloading structure were analyzed and the results of designing the fiber-reinforced concrete unloading structure and the regular concrete unloading structure were compared. As a result of the comparison, it was found that using fiber-reinforced concrete decreases the cross-section diameter of the effective reinforcement of the slab – the cross-section diameter of the effective reinforcement of the pavement slab decreases from Æ2×32 mm to Æ32 mm in the upper and Æ25 mm in the lower row, respectively. Crack resistance is also increased compared to regular concrete. Thus, in order to create structures with high transport and operational parameters, it is necessary to modify fiber-reinforced concrete mixtures with complex additives

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The strength of compressed structures with CFRP materials reinforcement when exceeding the cross-section size

E3S Web of Conferences ◽

10.1051/e3sconf/20183302060 ◽

2018 ◽

Vol 33 ◽

pp. 02060 ◽

Cited By ~ 4

Author(s):

Petr Polskoy ◽

Dmitry Mailyan ◽

Sergey Georgiev ◽

Viktor Muradyan

Keyword(s):

Bearing Capacity ◽

Cross Section ◽

High Strength ◽

Material Consumption ◽

High Rise ◽

Labour Costs ◽

Section Size ◽

Strength And Deformation ◽

The Cross ◽

Composite Reinforcement

The increase of high-rise construction volume or «High-Rise Construction» requires the use of high-strength concrete and that leads to the reduction in section size of structures and to the decrease in material consumption. First of all, it refers to the compressed elements for which, when the transverse dimensions are reduced, their flexibility and deformation increase but the load bearing capacity decreases. Growth in construction also leads to the increase of repair and restoration works or to the strengthening of structures. The most effective method of their strengthening in buildings of «High-Rise Construction» is the use of composite materials which reduces the weight of reinforcement elements and labour costs on execution of works. In this article the results of experimental research on strength and deformation of short compressed reinforced concrete structures, reinforced with external carbon fiber reinforcement, are presented. Their flexibility is λh=10, and the cross-section dimensions ratio b/h is 2, that is 1,5 times more, than recommended by standards in Russia. The following research was being done for three kinds of strained and deformed conditions with different variants of composite reinforcement. The results of the experiment proved the real efficiency of composite reinforcement of the compressed elements with sides ratio equal to 2, increasing the bearing capacity of pillars till 1,5 times. These results can be used for designing the buildings of different number of storeys.

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A New Approach to the Demonstration of Oxidase-Localization Using Tannic Acid Or Catechin

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100073933 ◽

1973 ◽

Vol 31 ◽

pp. 698-699

Author(s):

V. Mizuhira ◽

Y. Futaesaku

Keyword(s):

Cross Section ◽

Tannic Acid ◽

Elastic Fiber ◽

The Other ◽

New Approach ◽

Tissue Block ◽

Active Reaction ◽

The Cross

Previously we reported that tannic acid is a very effective fixative for proteins including polypeptides. Especially, in the cross section of microtubules, thirteen submits in A-tubule and eleven in B-tubule could be observed very clearly. An elastic fiber could be demonstrated very clearly, as an electron opaque, homogeneous fiber. However, tannic acid did not penetrate into the deep portion of the tissue-block. So we tried Catechin. This shows almost the same chemical natures as that of proteins, as tannic acid. Moreover, we thought that catechin should have two active-reaction sites, one is phenol,and the other is catechole. Catechole site should react with osmium, to make Os- black. Phenol-site should react with peroxidase existing perhydroxide.

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Energy Distribution in Electron Beams

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100096096 ◽

1972 ◽

Vol 30 ◽

pp. 568-569

Author(s):

Tamotsu Ohno

Keyword(s):

Electron Beam ◽

Energy Distribution ◽

Cross Section ◽

Integral Curve ◽

Electron Beams ◽

Electron Gun ◽

Angular Divergence ◽

Apparent Increase ◽

Integral Width ◽

The Cross

The energy distribution in an electron; beam from an electron gun provided with a biased Wehnelt cylinder was measured by a retarding potential analyser. All the measurements were carried out with a beam of small angular divergence (<3xl0-4 rad) to eliminate the apparent increase of energy width as pointed out by Ichinokawa.The cross section of the beam from a gun with a tungsten hairpin cathode varies as shown in Fig.1a with the bias voltage Vg. The central part of the beam was analysed. An example of the integral curve as well as the energy spectrum is shown in Fig.2. The integral width of the spectrum ΔEi varies with Vg as shown in Fig.1b The width ΔEi is smaller than the Maxwellian width near the cut-off. As |Vg| is decreased, ΔEi increases beyond the Maxwellian width, reaches a maximum and then decreases. Note that the cross section of the beam enlarges with decreasing |Vg|.

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Research in the cross-section of community psychology and global climate change: A call for action

PsycEXTRA Dataset ◽

10.1037/e628592012-083 ◽

2009 ◽

Author(s):

Marci Culley ◽

Holly Angelique ◽

Courte Voorhees ◽

Brian John Bishop ◽

Peta Louise Dzidic ◽

...

Keyword(s):

Climate Change ◽

Cross Section ◽

Global Climate Change ◽

Community Psychology ◽

Global Climate ◽

The Cross

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Experimental Studies Of Multilayer Glass Structures On Compression, Compression With Bending And Simple Bending

Promyshlennoe i Grazhdanskoe Stroitel stvo ◽

10.33622/0869-7019.2019.01.22-30 ◽

2019 ◽

pp. 22-30

Keyword(s):

Cross Section ◽

Cross Sections ◽

Applied Load ◽

Experimental Studies ◽

Strength Properties ◽

Research Topic ◽

Normative Values ◽

Laminated Glass ◽

The Cross ◽

Experimental Values

The work of multilayer glass structures for central and eccentric compression and bending are considered. The substantiation of the chosen research topic is made. The description and features of laminated glass for the structures investigated, their characteristics are presented. The analysis of the results obtained when testing for compression, compression with bending, simple bending of models of columns, beams, samples of laminated glass was made. Overview of the types and nature of destruction of the models are presented, diagrams of material operation are constructed, average values of the resistance of the cross-sections of samples are obtained, the table of destructive loads is generated. The need for development of a set of rules and guidelines for the design of glass structures, including laminated glass, for bearing elements, as well as standards for testing, rules for assessing the strength, stiffness, crack resistance and methods for determining the strength of control samples is emphasized. It is established that the strength properties of glass depend on the type of applied load and vary widely, and significantly lower than the corresponding normative values of the strength of heat-strengthened glass. The effect of the connecting polymeric material and manufacturing technology of laminated glass on the strength of the structure is also shown. The experimental values of the elastic modulus are different in different directions of the cross section and in the direction perpendicular to the glass layers are two times less than along the glass layers.

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