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Innowacyjne prefabrykaty łukowe o podwyższonej trwałości przeznaczone dla budownictwa komunikacyjnego. Cz. I. Badania porównawcze prefabrykatu żelbetowego

Michalak Ewa, Piątek Bartosz, Stryszyk-Wieloszewska Bogumiła

Mosty

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2020

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nr 2

39--43

PL

Od lipca 2018 r. do listopada 2019 r. firma OPTEM wraz z Zakładem Dróg i Mostów Politechniki Rzeszowskiej realizowały projekt badawczy pt.: „Innowacyjne prefabrykaty łukowe o podwyższonej trwałości przeznaczone dla budownictwa komunikacyjnego”, którego celem było opracowanie nowego prefabrykatu łukowego optemARCH. W rezultacie otrzymano znacząco ulepszony wyrób budowlany charakteryzujący się mniejszym ciężarem oraz podwyższoną odpornością na korozję.

EN

From July 2018 to November 2019, OPTEM company together with the the Department of Roads and Bridges at Rzeszow University of Technology implemented a research project „Innovative prefabricated arched components of increased durability for transportation engineering”, the aim of which was to develop a new optemARCH prefabricated arch. As a result, a significantly improved construction product of lower weight and totally corrosion resistant was obtained.

2

Safety of formworks in the engineering and general construction sector

Brózda Kinga, Selejdak Jacek

System Safety : Human - Technical Facility - Environment

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2019

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Vol. 1, nr 1

284--290

EN

Formwork systems are necessarily used in the implementation of the RC (reinforced concrete) structures. Formworks are required regardless of whether a construction is monolithic or prefabricated and used to form the engineering and general structures or structural elements, such as abutments, supports and decks of the bridges, tanks and retaining walls, but also industrial and accommodation facilities etc. Ensuring the OHS (occupational health and safety) during transport, assembly and disassembly of formworks is a necessary condition for the execution of RC works in a safe and economical way. The paper presents the analysis of the safety requirements for formworks. Furthermore, the general requirements for the execution of the formwork structures were discussed. The most common organizational and technological mistakes and cased of neglects related to the operation of the formwork which lead to infringement of the OHS regulations were also identified.

3

The influence of the damaged reinforcing bars on the stress-strain state of the rein-forced concrete beams

Blikharskyy Z., Shnal T., Khmil R.

Production Engineering Archives

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2017

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Vol. 14

23--26

EN

The article is devoted to the overall view of experimental research of reinforced concrete beams with the simultaneous influence of the corrosion environment and loading. The tests have been carried out upon the reinforced concrete specimens considering the corrosion in the acid environment, namely 10 % H2SO4 that have been taken as a model of the aggressive environment. The beams are with span equalling to 1,9m with different series of tensile armature, concrete compressive strength and different length of impact of corrosion (continuous and local). The influence of simultaneous action of the aggressive environment and loading on strength of reinforced-concrete beams has been described. For a detailed study of the effect of individual components there was suggested additional experimental modelling of the only tensile armature damage without concrete damage. It will investigate the influence of this factor irrespective of the concrete.

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A novel formulation of 3D spectral element for wave propagation in reinforced concrete

Rucka M., Witkowski W., Chróścielewski J., Burzyński S.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2017

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Vol. 65, nr 6

805--813

EN

The paper deals with numerical simulations of wave propagation in reinforced concrete for damage detection purposes. A novel formulation of a 3D spectral element was proposed. The reinforcement modelled as the truss spectral element was embedded in the 3D solid spectral finite element. Numerical simulations have been conducted on cuboid concrete specimens reinforced with two steel bars. Different degradation models were considered to study the real behaviour of bended beams.

5

Effect of concrete addition of selected micro-fibers on the reinforcing bars corrosion in the reinforced concrete specimens

Raczkiewicz W.

Advances in Materials Science

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2016

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Vol. 16, nr 3(49)

38--46

EN

The micro-fibers increase the consistency and uniformity of concrete, which can improve the protective properties of concrete cover and thus should reduce the corrosion of the reinforcement bars in the reinforced concrete elements. The article presents a study which main objective was to specify the effect on concrete mix the addition of steel or polypropylene micro-reinforcement fibers on the reinforcing bars corrosion process. The research included measuring the reinforcement corrosion progress caused by the chloride impact as well as cyclical freezing and thawing specimens test. To measure the electrochemical corrosion progress the non-destructive i.e. galvanostatic pulse method was used. The results were used to conduct a comparative analysis.

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Errors of stress numerical integration for cross-sections with straight and curved boundaries

Matuszak A.

Computer Assisted Methods in Engineering and Science

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2015

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Vol. 22, no. 2

153--176

EN

Internal forces are integrals of stress in a section area. Integrating the stress for an arbitrary cross-section shape and for the nonlinear stress-strain law σ(ε) is tedious and the use of the boundary integral approach can simplify computations. Numerical integration when applied to the computations of such integrals introduces errors in many cases. Errors of numerical integration depend on the adopted integration scheme, the type of σ(ε) and the shape of the cross-section boundary. In the case of adaptive numerical integration what is very important are the properties of the sequence of errors produced by a given integration scheme in the increasing order of the numerical quadrature or the increasing number of subdivisions. This paper analyses errors caused by different integration schemes for the typical σ(ε) either for a straight or curved boundary. Special attention is paid to the properties of the error sequence in each case. The outcome of this paper is important from the viewpoint of the reliability and robustness of the software developed for nonlinear simulations of bar structures.

7

Assessment of uncertainty in the resistance models of concrete members

Woliński Sz.

Architecture Civil Engineering Environment

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2015

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Vol. 8, no. 4

73--78

EN

The paper presents an analysis and evaluation methods of uncertainty in the resistance models of reinforced concrete elements. The first method is based on the standardized procedure for calibration of resistance models recommended in the Eurocode. The second method is an original proposal for the assessment of uncertainty in the resistance models using a simplified probabilistic method and the reliability index as the measure of structural safety. According to the concept of semi-probabilistic partial factors design, the partial factor resulting from model uncertainty which is separated from the factor for resistance, represents the measure of model uncertainty. The proposed approaches to the model uncertainty assessment have been demonstrated using resistance models for bending and shear capacity of reinforced concrete beams.

PL

W artykule przedstawiono analizę i metody oceny niepewności modeli nośności elementów żelbetowych. Pierwsza metoda opiera się na standardowej procedurze kalibracji modeli zalecanej w Eurokodzie. Druga metoda to oryginalna propozycja oceny niepewności modeli nośności z wykorzystaniem uproszczonej metody probabilistycznej oraz wskaźnika niezawodności jako miary bezpieczeństwa konstrukcji. Zgodnie z półprobabilistyczną koncepcją projektowania z wykorzystaniem częściowych współczynników, współczynnik związany z niepewnością modelu, który został wydzielony z częściowego współczynnika nośności, stanowi miarę niepewności modelu. Proponowany sposób oceny niepewności modelowej przedstawiono na przykładach modeli nośności zginanych i ścinanych belek żelbetowych.