ESTIMATED JUSTIFICATION OF TECHNICAL DECISION ON STRENGTHENING REINFORCED CONCRETE MACHINE HALL FLOOR

Introduction. In connection with the long-term operation of hydraulic structures (HPP), the installation of significant temporary loads, the presence of alternating effects on individual structural elements, it is possible to reduce the carrying capacity and strength of reinforced concrete structures. One of the most crucial elements is the reinforced concrete overlap of the machine hall, the work presents field and design studies, a proposal to strengthen the structures with external reinforcement. Materials and methods. The scientific and technical documentation was analyzed, instrumental studies and visual inspections of the state of the structures were carried out, and a 3D mathematical model was developed based on the finite element method. Multivariate non-linear computational studies of the actual stress-strain state of structures have been carried out. Results. Conducted visual and instrumental examination showed the presence of cracking on the lower edge of the reinforced concrete floor of the machine room. The simulation of the actual state of the structures has been carried out; according to the results of calculations, a schematic diagram of the gain of structures has been proposed. Conclusions. As a result of computational studies of stress-strain state, the occurrence of cracks on the lower edge of reinforced concrete floor of the machine hall was confirmed. When applying temporary technological loads to overlap, it is possible to achieve the yield strength of the reinforcement in certain zones. In order to ensure further safe operation of the structures, a conceptual amplification scheme based on the results of stress-strain state calculations has been proposed

New 2,5-bis(2-ethylhexyl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione-2,2’-bipyridine-based co-polymer, synthesis, photophysical properties and response to metal cations

A new co-polymer based on fragments of 2-(2-pyridyl)monoazatriphenylene and 2,5-bis (2-ethylhexyl)-3,6-di(thiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione was prepared by using the Sonogashira reaction. The photophysical properties of the polymer were studied. The presence of a strong bathochromic shift of the absorption and emission maxima in comparison with the previously described monomer units is shown. The polymer exhibits an intense “turn-off” response toward Cu2+ cations

(Mechano)synthesis of azomethine- and terpyridine-linked diketopyrrolopyrrole-based polymers

Three efficient synthetic approaches towards new azomethine- and terpyridine-containing 2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione (diketopyrrolopyrrole, DPP) based polymers, such as P1 and P2, are reported. The first approach involves the Pd-catalyzed synthesis via two- or three-component Suzuki or Stille cross-coupling reaction in solution. The second approach involves Pd-catalyzed Suzuki cross-coupling reaction under ball-milling conditions. And, finally, the third approach involves Pd-free condensation reaction under ball-milling conditions. The newly obtained polymers exhibited absorbance around 700 nm and emission around 900 nm, and, thus, these polymers are considered to be NIR-fluorophores

Accounting for the filling of the reservoir when calculating the stress-strain state of a concrete dam

The aim of work. The paper considers the issue of reservoir accounting when calculating the stress-strain state of a concrete dam and its foundation. Solution technique. As a rule, reservoirs on a global scale represent a large gravitational mass in the form of water, which affects the engineering-geological situation in a large deep of rocks foundation. To study this factor, an investigation was made of the power component of the reservoir on the basis of the “reservoir - structure - rock foundation” system. For the calculations, the hydro power plant of Boguchanskaya HPP was selected, which is part of the Angara river cascade and is located in Siberia. To perform the stress-strain state calculations, a three-dimensional mathematical finite element model of the “reservoir - structure - rock foundation” system was created on the basis of which the predicted values of the calculated draft of the concrete dam are determined. The mathematical model consists of a fragment of the rock foundation, represented by the lithosphere and the upper part of the asthenosphere. To verify the proposed reservoir account, the predicted sediment values were compared with geodesic data, while the comparison results showed a high degree of correlation. A high degree of correlation suggests that the proposed method predicts the rock foundation and structure sediments quite well when filling the reservoir. Results. The results of the conducted investigations and comparisons of calculated and field data have shown the necessity of reservoir accounting when calculating predictions of sediment values of hydraulic structures and their rock foundation. This forecast is quite important in determining the criterial values of diagnostic indicators for the safety control of the structure