This research aims to develop an algorithm that allows for the analysis of the influence of interlayer connections on the static response of double-layer beams. Since their construction uses the advantages of different materials, multilayer beams are widely used in the construction industry. The critical element of these types of structures is the connection between layers, the stiffness of which can significantly affect the static response of the system, and therefore its strength. The Euler-Bernoulli model was used to describe the double-layer beams. In the paper, the compliance of normal displacements in multilayer and double-layer beams was considered based on the research of other authors. It was also assumed that the tangential interactions at the connection of layers were tangential forces that are proportional to the relative tangential displacement (slip) of these layers. This general approach eliminates the need for a broader analysis of the connection (its description and structure) with regard to the applied “connector” between the layers. Using equilibrium equations and the adopted assumptions, a system of displacement equations was derived. This system is formed by three coupled second- and fourth-order differential equations, the exact solution of which is a nontrivial mathematical problem. This system was solved using the finite sine and cosine Fourier transform. Although the algorithm presented in the paper was used to solve a specific set of equations that describe a simply supported beam, the formulas derived in the paper allow for solving beams with other support schemes. The Fourier transformation method, after appropriate modifications (changing the boundary conditions and, in some cases, changing the sine to cosine transformation and vice versa), can be used to solve beams that have other support conditions. To verify the correctness and effectiveness of the described method, two numerical examples were solved. In the first one, the influence of the variable value of the tangential stiffness of the connection on the values ??and distribution of internal forces (including the influence on the values ??of normal stresses) was analyzed. In the second example, calculations were performed for an example taken from the literature, and the obtained results were compared with the results obtained by other authors. The analyzed examples confirmed the significant influence of the tangential stiffness of the layer connection on the static response of the system. Furthermore, they confirmed the correctness and high accuracy of the method that was used to solve the problem.
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Przedstawiono wybrane przykłady wad i uszkodzeń wielkopowierzchniowych podłóg o konstrukcji betonowej. Wprowadzono podstawową klasyfikację przyczyn uszkodzeń, dzieląc je z uwagi na usytuowanie w konstrukcji oraz umiejscowienie w procesie inwestycyjnym.
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The article presents selected examples of defects and damages of large-area concrete floors. A basic classification of the causes of damages was proposed, divided according to the location of the damage in the structure and stage of the investment process.
Przedstawiono wyniki doświadczalnych badań elementów składających się ze sklepienia murowego oraz materiału zasypowego. Przyjęto trzy sposoby przygotowania grzbietu sklepienia. Wyniki badań wskazują, że sposób przygotowania grzbietu sklepienia wpływa na nośność i pracę badanego układu konstrukcyjnego.
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This article presents the results of experimental tests on barrel vaults with fill material. In the experimental program three different finishing methods of vaults extrados were taken into consideration. The results of the tests showed that finishing of vaults extrados had influence on behaviour and load-carrying capacity of tested elements.
Huge water reservoirs exist subglacially, for instance in the form of lakes. Failure of a wall around such a lake underneath the central part of a large ice mass may result in huge water outbursts. The resulting megafloods will rarely be traceable along the ice front, because much power is lost by friction and because the flood spreads subglacially over a large area. Truly giant meltwater outbursts might, however, still have an enormous power when reaching the marginal area of an ice cap. Such a megaflood may both affect the integrity of the ice mass, and help create a sliding layer over which huge ice masses can be easily transported towards the ocean, thus triggering a Heinrich-like event. This would have great impact on the global climate. Some of the Heinrich events that occurred during the past hundreds of thousands of years may well have been due to giant subglacial water outbursts, and such a situation may equally well occur in the time to come.
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Omówiono problemy związane z remontem trzonu pieca czynnej baterii koksowniczej z dolnym doprowadzeniem gazu opałowego. Przedstawiono ogólne zasady postępowania przy jego renowacji oraz szczegółowy opis opracowanej i wdrożonej metody wymiany załamanego trzonu jednego z pieców baterii typu PWR-68. Opisana metoda, uwzględniająca różnice rozszerzalności części podlegającej odbudowie i części pozostawianej do dalszej eksploatacji, polega na trwałym rozdzieleniu odbudowywanej ceramiki warstwą poślizgową, zmianie jej gabarytów i wkomponowaniu ściśle określonych poprzecznych szczelin dylatacyjnych.
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The problem conntected with repairing of the heart of coke oven battery with bottom-supply of heating gas has been discussed. The main rule of the renovation procedures and the detailed description of worked out and implemented method of broken heart replacing for coke oven battery PWR-63 type has been shown. Described method take into consideration the expansion differences between new ceramics (the subject of repairing) and the old one (parts left for further exploitation). The method consists in total separation of reconstructed ceramics by slide layer, change of its overall dimension and using of precisely designed expansion gaps.
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