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PL
Opisano rozwiązania konstrukcyjne pierwszych w Polsce kładek podwieszonych. Nietypowe i eksperymentalne rozwiązania stosowane w tych konstrukcjach, w połączeniu z ich wieloletnią eksploatacją, nierzadko stanowią wyzwanie dla ich zarządców w zakresie bieżącego utrzymania i remontów. Zestawiając oceny stanu technicznego głównych elementów nośnych, wskazano jednocześnie na dużą wartość historyczną tych pionierskich konstrukcji w kontekście polskiego mostownictwa. Ich przebudowa lub rozbiórka powinny być ostatecznością.
EN
The issues of early Polish cable-stayed footbridges are presented in this paper. Atypical and experimental structures of mentioned footbridges, combined with their long-time service, are quite often a challenge, regarding routine maintenance and repairs. While listing technical condition evaluation marks, great historical value of these pioneer structures considering bridge engineering in Poland was also emphasized. Finally, it was highlighted that reconstruction or demolition of the footbridges should be considered only if unavoidable.
EN
In this work on the basis of the developed and tested mathematical model, the numerical experiment is conducted in order to study in more detail the specifics of performance of concrete beams` with combined reinforcement. For this purpose nine series of reinforced concrete beams with different combination of steel bars (A400C, At800, A1000) and ribbon reinforcement (C275) were modeled. In the developed series two classes of concrete were used: C50/60, C35/45. The functions derived on the basis of mathematical modeling allow us to determine the recommended percentage of high-strength reinforcement of common reinforced concrete structures with single reinforcement. Therefore, the possibility is obtained to reduce the total structures` reinforcement percentage, increasing their deformability by the specified value without affecting the bearing capacity.
3
Content available remote Wartość zużycia a koszty przywrócenia właściwości użytkowych
PL
Z upływem czasu następuje pogorszenie właściwości użytkowych budynku, a ich całkowite lub częściowe przywrócenie następuje w wyniku napraw i remontów. Zadaniem zarządców czy właścicieli nieruchomości jest utrzymanie budynków w niepogarszającym się stanie technicznym i użytkowym. Nie jest to zadanie łatwe, jego realizacja wymaga odpowiedniego wsparcia procesów decyzyjnych dotyczących prowadzenia racjonalnej gospodarki remontowej. W artykule przedstawiono propozycję modelu pozwalającego na właściwe szacowanie kosztów prac remontowych i naprawczych budynku na określonym etapie eksploatacji i ich relacji zwartością zużycia technicznego budynku w tym samym okresie. Analizie poddano budynki mieszkalne wykonane w technologii tradycyjnej. Do określenia kosztów prac remontowych koniecznych do przywrócenia właściwości użytkowych zastosowano model zmian właściwości użytkowych PRRD (Prediction of Reliability according to Rayleigh Distribution), a wartość zużycia ustalono na podstawie stopnia zużycia technicznego i kosztu odtworzenia.
EN
With time, the building's functional properties are reduced, and their total or partial restoration takes place as a result of repairs and renovations. The task of managers or property owners is to keep buildings in a non-deteriorating technical and functional condition. It is not an easy task, its implementation requires appropriate support for decision-making processes concerning rational renovation management. This article presents a proposal for a model allowing for proper estimation of the costs of repair and repair works of a building at a given stage of operation and their relation with the value of technical use of a building in the same period of time. The analysis was made of residential buildings made in traditional technology. To determine the costs of renovation works necessary to restore functional properties, the model of changes in functional properties was used (Prediction of Reliability according to Rayleigh Distribution), and the value of consumption was determined on the basis of the degree of technical wear and replacement cost.
EN
The aim of this study was to assess technical feasibility of servicing for modern agricultural tractors. Labour intensity of technical service during the entire servicing cycle was adopted as a measure of serviceability for agricultural tractors. Among tractors included in this study the lowest labour intensity of technical service (Pst = 25 h) was observed for Forterra 105 tractors by Zetor.
PL
Celem pracy była ocena technologiczności serwisowania współczesnych ciągników rolniczych. Jako miarę podatności serwisowej ciągników rolniczych przyjęto pracochłonność serwisu technicznego w okresie pełnego cyklu serwisowego. Spośród ciągników objętych badaniami najmniejszą pracochłonność serwisu technicznego (Pst = 25 h) zaobserwowano w przypadku ciągników marki Zetor Forterra 105.
EN
Reinforced concrete piles employed in earth retaining systems are typically designed with symmetric reinforcement. The non-symmetric RC wall piles have recently been introduced by the authors, obtaining savings of up to 50% in weight in longitudinal reinforcing steel compared with the traditional solutions, leading to significant financial savings while also reducing associated environmental impacts. The structural behavior of this new RC member under long-term loading is studied, comparing it with its symmetrical counterpart. An experimental campaign has been carried out. Full scale specimens with circular cross sections symmetrically and asymmetrically reinforced were tested. Results have shown that asymmetrically RC pile developed a slightly higher deflection than its symmetrical counterpart. A new expression for the effective area of concrete in tension applicable to non-symmetrical piles is introduced. Moreover, a new stress–strain law for cracked concrete that accounts the tension stiffening effect for long-term loading is proposed. Finally, for non-symmetrical RC wall piles, the evolution of the parameter that takes into account the duration of loading in deformations is presented. Although more evidence is needed, it is shown that tension stiffening effect contribution could be overestimated by Eurocode 2 in the case of non-symmetrically or underestimated in case of symmetrically RC piles.
EN
The paper describes a new methodology that allows to design scalable complex control and data acquisition systems taking into consideration the additional, non-functional requirements of High-Energy Physics (HEP). Electronic systems applied in HEP often operate in difficult conditions. Access to such devices is difficult or even impossible. The HEP systems require high availability, serviceability and upgradeability. The operating conditions of these systems are even more difficult than for telecommunication devices. Therefore, a different methodology should be applied than for classical telecommunication systems, when designing electronics used in high-energy physics applications. Electronic systems also need a suitable hardware platform that not only assures high availability, simplifies maintenance and servicing but also allows to use mixed analogue-digital signals. The author made an attempt to develop a new methodology suitable for designing of complex data acquisition and control systems of HEP. The Low Level RF (LLRF) system of European Free Electron Laser (EXFEL) and Image Acquisition System (IAS) prototype developed for International Thermonuclear Experimental Reactor (ITER) tokamak are presented as examples of complex electronic systems that were designed according to the proposed methodology.
EN
In this article serviceability of reinforced concrete columns, strengthened by reinforced concrete jacketing was investigated. Performance of reinforced concrete columns strengthened after initial loading was studied. Different loading levels before strengthening were considered.
PL
W artykule zaprezentowano wyniki badań doświadczalnych dotyczących trwałości słupów żelbetowych przed i po wzmocnieniu z zastosowaniem obejm żelbetowych. Badano wzmocnienia słupów, wstępnie obciążonych do różnych poziomów wyczerpania nośności.
PL
W pracy zaprezentowano model wyznaczania informacji obsługowej w zakresie wyznaczania zbioru czynności obsługowych odnawiających elementy obsługowe odnawianego obiektu. Podstawą do wyznaczania zbioru czynności obsługowych elementów obiektu są: stany tych elementów oraz ich klasy obsługowe. W opracowanym modelu ważnymi jego elementami są zależności opisujące ten proces oraz opracowane reguły ekspertowe, które organizują ten proces tworzenia macierzy czynności obsługowych.
EN
The paper presents a model for determining the operating information regarding the identification of a set of operations renewing the renovated facility operating elements. The basis for determining the set of operations of items are: stocks of these elements, and their class maintenance. In the developed model elements are important equations describing this process and developed expert rules that organize the process of creating a matrix maintenance.
EN
The various possible stages of the separator's work, including full and partial readiness to work and unserviceability have been considered. Oil separator transition through each of the working stages has been described. Typical oil separator damages have been specified. It has also been pointed out that there are possibilities to diagnose separators during their working time. The significance of separator starting time until the moment of achieving nominal working parameters has been emphasised. For the selected type of separator, nominal parameter values have been defined. The possibilities of measuring the oil separator working parameters and applying them to diagnose its ability to work have been described.
PL
Przedstawiono możliwe stany pracy wirówek, uwzględniając stan pełnej zdatności, częściowej zdatności i niezdatności. Wskazano miejsca typowych uszkodzeń występujących w wirówkach oleju. Wskazano na możliwość diagnozowania wirówek w czasie pracy i podkreślono znaczenie czasu rozruchu wirówki do momentu uzyskania parametrów nominalnych pracy. Dla wybranego typu wirówki przedstawiono nominalne wartości parametrów pracy. Opisano możliwość pomiarów parametrów pracy wirówki i wykorzystanie ich do zdiagnozowania jej zdatności.
EN
On the background of the demand for an extended transmission capacity, the principles of static and dynamie behaviour of reinforced TV and telecommunication towers were investigated exemplarily at the Cottbus tower. The experimental part of the investigations is based on wind tunnel tests and permanent long-time measurements by a monitoring system acquiring data of wind situation and vibration velocity. The numerical part of the investigations was covered by conventional stochastic and deterministic methods for the calculation of the structural response due to along-wind and vortex shedding as well as by a new, hybrid and more close to reality numerical method based on neural networks. It could be shown that the serviceability of the Cottbus tower is actually not subjected to danger. The largest inclinations concerning permanent operation of transmission facilities result from along-wind and nonuniform temperature loadings over the shafts cross-section. As the most critical loading, with regard to questions of comfort and long-time behaviour, vortex shedding at the aerial antenna could be identified. Moreover, considerable reserves with a view to an extension of transmission facilities could be proved. Nevertheless, it was shown that these extensions cause a considerable increase in along-wind loadings, which could effect a critical structural response in case of towers having a lower stiffness. In order to avoid any risk from the outset, a strategy for planning operational changes was proposed on principle.
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