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1
Content available Investigation of Resilience of Eccentrically Braced Frames Equipped with Shape Memory Alloys
Pirmoghan Hamid, Khoshravi Hossein, Sadeghi Abbasali, Pouraminian Majid, Noroozinejad Farsangi Ehsan
Civil and Environmental Engineering Reports
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2022
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Vol. 32, no. 1
176--190
EN
Nowadays, the use of smart materials in structures is a major concern to structural engineers. The act of benefiting from numerous advantages of these materials is the main objective of researches and studies focused on seismic and structural engineering. In the present study, in addition to the development of finite element models of several steel frames using ABAQUS software, the effect of shape memory alloys (SMAs) on superelastic behavior and the various types of eccentric braces will be checked. Moreover, it was observed that the use of SMAs within various types of bracing systems of steel frames leads to a decrease in the reduction factor of the frames. Also, the eccentric bracing in which SMAs are utilized in the middle of bracing led to the highest effect on reduction of lateral drift of the frames and decrease of reduction factor. The obtained results indicated that the application of smart materials led to increasing of strain energy and base shear of the first plastic hinge, which is followed by a decrease in the reduction factor of the frame.
2
Content available Calculation of the thermal dynamic performance of the residential buildings' walls
Kalinović Saša M., Djoković Jelena M., Nikolić Ružica R., Hadzima Branislav
Quality Production Improvement - QPI
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2019
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Vol. 1, Iss. 1
212--221
EN
Calculation of the thermal dynamic properties of the multi-layer wall isolation of residential buildings is presented in this paper. Taking into account that the final objective is to create a building with the highest energy efficiency ratio, i.e. with the lowest energy consumption, both for heating and cooling, it is necessary to realize the good thermal characteristics of the multi-layer wall. To obtain the optimal solution for the wall's structure, various wall structures with different thicknesses of the individual layers, were analyzed. Based on results, presented in this paper, one can conclude that for walls with the same total thickness, but various thicknesses of the individual layers, that constitute the complete wall structure, the differences appear in the delay of the change of the walls outside temperature. In that way, by varying those individual layers' thicknesses, one can obtain the optimal solution for the wall structure with the highest savings of energy.
3
Content available Assessment of the strength reduction factor in predicting the flexural strength
Alacali S., Arslan G.
Journal of Theoretical and Applied Mechanics
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2018
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Vol. 56 nr 4
1043--1053
EN
In the design of flexural strength, the strength reduction factor φ decreases from tension- -controlled sections to compression-controlled sections to increase safety with decreasing ductility. This paper presents how to determine the reduction factor for flexural strength of reinforced concrete beams according to ACI code. In the reliability-based design, the reliable prediction of the flexural strength of reinforced concrete members is assured by the use of reduction factors corresponding to different target reliability index β. In this study, for different β and coefficients of variation of the flexural strength parameters, the flexural strength reduction factor has been investigated by using experimental studies available in the literature. In the reliability analysis part of the study, the first-order second moment approach (FOSM) has been used to determine the reduction factor. It has also been assumed that the random variables are statistically independent.
4
Analiza nośności blachownic stalowych eksploatowanych w podwyższonej temperaturze technologicznej
Gwóźdź M.
Inżynieria i Budownictwo
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2018
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R. 74, nr 9
463--465
PL
Sformułowano analitycznie wartości dyskretne współczynników redukcyjnych cech mechanicznych stali, podanych w normie PN-EN 1993-1-2, oraz wyznaczono temperaturę krytyczną, po której przekroczeniu dochodzi do redukcji nośności plastycznej. Sposób wykorzystania proponowanych formuł analitycznych w przypadku współczynników redukcyjnych zilustrowano przykładem z praktyki inżynierskiej.
EN
The discrete values of reduction factors for mechanical properties of steel that were given in PN-EN 1993-1-2 are formulated analytically. Critical temperature for which there is a reduction of the plastic resistance is defined. The method of using for proposed analytical formulations for reduction factors is presented on an example taken from engineering practice.
5
Content available remote Analiza nośności na zginanie belki swobodnie podpartej zbrojonej prętami FRP
Brózda K., Selejdak J.
Materiały Budowlane
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2017
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nr 5
55--56
PL
W artykule zaprezentowano rodzaje prętów kompozytowych stosowanych do zbrojenia konstrukcji betonowych oraz ich podstawowe cechy mechaniczne i fizyczne. Przedstawiono dostępne zalecenia projektowe dotyczące wymiarowania zbrojenia FRP oraz porównano współczynniki redukujące stany graniczne nośności i użytkowalności. Przeprowadzona została również analiza obliczeniowa nośności na zginanie belki swobodnie podpartej zbrojonej prętami CFRP, AFRP oraz GFRP. Ponadto określono różnice uzyskanych parametrów, wynikające z cech fizykomechanicznych poszczególnych rodzajów prętów FRP.
EN
The article discusses the types of FRP bars and presents their basic mechanical and physical characteristics. The available design recommendations for the FRP reinforcement dimensioning are presented. Moreover, the ultimate limit state (ULS) and the serviceability limit state (SLS) reduction factors are compared. The theoretical design of FRP-reinforced concrete simply supported beam forflexure was analyzed. The CFRP, AFRP and GFRP bars were used. Subsequently, differences between obtained parameters, resulting from the physical and mechanical characteristics of the various types of FRP rebar were determined.
6
Content available Impact of waste heat recovery systems on energy efficiency improvement of a heavy-duty diesel engine
Ma Z., Chen H., Zhang Y.
Archives of Thermodynamics
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2017
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Vol. 38, no. 3
63--75
EN
The increase of ship’s energy utilization efficiency and the reduction of greenhouse gas emissions have been high lightened in recent years and have become an increasingly important subject for ship designers and owners. The International Maritime Organization (IMO) is seeking measures to reduce the CO2 emissions from ships, and their proposed energy efficiency design index (EEDI) and energy efficiency operational indicator (EEOI) aim at ensuring that future vessels will be more efficient. Waste heat recovery can be employed not only to improve energy utilization efficiency but also to reduce greenhouse gas emissions. In this paper, a typical conceptual large container ship employing a low speed marine diesel engine as the main propulsion machinery is introduced and three possible types of waste heat recovery systems are designed. To calculate the EEDI and EEOI of the given large container ship, two software packages are developed. From the viewpoint of operation and maintenance, lowering the ship speed and improving container load rate can greatly reduce EEOI and further reduce total fuel consumption. Although the large container ship itself can reach the IMO requirements of EEDI at the first stage with a reduction factor 10% under the reference line value, the proposed waste heat recovery systems can improve the ship EEDI reduction factor to 20% under the reference line value.
7
Content available The investigation of the strength reduction factor in predicting the shear strength
Arslan G., Alacali S. N., Sagiroglu A.
Journal of Theoretical and Applied Mechanics
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2015
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Vol. 53 nr 2
371--381
EN
Design codes propose to restrict the nominal probability of failure within specific target structural reliability levels using a load factor and a strength reduction factor. In the current ACI318 Code, the strength reduction factor varies from 0.65 to 0.90, and the value considered in predicting the shear strength equals to 0.75. In this study, the change in the strength reduction factor in predicting the shear strength according to ACI318 has been investigated for different coefficients of variation of concrete compressive strength by using the first-order second moment approach, and the strength reduction factor is proposed for the target values of failure probability.
8
Szerokość efektywna ścianek przekrojów ze stali nierdzewnej
Tylek I.
Inżynieria i Budownictwo
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2015
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R. 71, nr 2
98--102
PL
Przedstawiono zagadnienia dotyczące wyznaczania szerokości współpracującej smukłych ścianek składowych przekrojów ze stali nierdzewnej oraz wskazano różnice i podobieństwa w normowych algorytmach obliczeniowych dotyczących przekrojów ze stali nierdzewnej według PN-EN 1993-1-4 i przekrojów ze stali węglowej zgodnie z PN-EN 1993-1-5.
EN
In the article determination of effective width of stainless steel cross-section slender parts was described. Some differences and similarities between design rules for stainless steel cross-sections according to PN-EN 1993-1-4 and carbon steel cross-sections according to PN-EN 1993-1-5 were pointed out.
9
Content available remote Screening coating for fire detectors
Katsuba A., Volochko A., Markov G., Ralko A.
Materiały Budowlane
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2014
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nr 10
115--116
EN
The paper considers coatings applied on the fire detectors for the improving of its noise stability in conditions of electro- magnetic radiation. In different branches of industry a lot of attention is paid to the protection of electronic objects from effects of strong electromagnetic fields. Electronic object can be a single electronic chip, detector with electronic components, computers, etc. All these electronic objects normally protected with separate metal screens, which are unhandy and not always suitable, for example, for the protection of small objects such as plastic fire detector SP 212 which is mass-produced in the Republic of Belarus.
10
Nośność blachownicowych belek podsuwnicowych ze środnikiem klasy 4
Żmuda J., Baran W., Respondek R.
Inżynieria i Budownictwo
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2012
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R. 68, nr 3
129-134
PL
Omówiono projektowanie według Eurokodu 3 belek podsuwnicowych ze smukłymi środnikami klasy 4. Wykazano, że projektowanie żeber podłużnych i poprzecznych smukłych środników belek podsuwnicowych jest w pełni uzasadnione. Na przykładzie obliczeniowym zobrazowano sposób określania nośności belek podsuwnicowych ze środnikami klasy 4.
EN
The article presents the problem of the design of crane beams with slender webs class 4 under the provisions of Eurocode 3. It is shown that the design of longitudinal and cross ribs slender webs of crane beams is fully justified. In the example illustrated the calculation method of determining the carrying capacity of the crane beams with webs of fourth class.
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