Wyniki wyszukiwania - BazTech

1

Non-contact method for measuring deformation in testing selected materials used in road construction

Górszczyk Jarosław, Malicki Konrad

Roads and Bridges - Drogi i Mosty

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2023

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Vol. 22, no. 4

423--432

EN

High requirements for materials used in road construction make it necessary to use modern methods for assessing the mechanical parameters of these materials. One such method is the Digital Image Correlation (DIC) method. The paper presents the possibilities of using the non-contact DIC method to measure deformation in testing selected mechanical properties of asphalt mixture samples and a composite made of a polymer matrix reinforced with a glass fiber grid (fiber reinforced polymer – FRP). The paper shows deformation analysis of all the observed surfaces of the tested samples. It was found that in terms of static tensile strength, the performance of the FRP tape is similar to the behavior of geogrids used to strengthen road pavement structures. The discussed results of own research and research described in the literature confirmed the usefulness of the DIC method in testing materials used in civil engineering.

PL

Wysokie wymagania stawiane materiałom stosowanym w budownictwie drogowym powodują konieczność stosowania nowoczesnych metod oceny ich parametrów mechanicznych. Jedną z takich metod jest metoda cyfrowej korelacji obrazu (Digital Image Correlation – DIC). W artykule zaprezentowano możliwości wykorzystania bezkontaktowej metody DIC do pomiaru deformacji w badaniach wybranych cech mechanicznych próbek mieszanki mineralno-asfaltowej oraz kompozytu wykonanego z matrycy polimerowej zbrojonej siatką z włókien szklanych – (fiber reinforced polimer – FRP). W pracy pokazano analizy deformacji całych obserwowanych powierzchni badanych próbek. Stwierdzono też, że pod względem wytrzymałości statycznej na rozciąganie praca taśmy FRP jest podobna do zachowania geosiatek stosowanych do wzmacniania konstrukcji nawierzchni drogowych. Omówione wyniki badań własnych oraz badań opisanych w literaturze potwierdziły przydatność metody DIC w badaniach materiałów stosowanych w inżynierii lądowej.

2

Calculation of the strength of reinforced concrete beams strengthened with composite materials

Borysiuk Oleksandr, Trach Roman

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska

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2023

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Vol. 32, No. 1

53--68

EN

Currently, in view of the previous theoretical and experimental researches, the regulatory documents for the calculation of reinforced concrete elements strengthened by composite materials and the calculation and design of fiber reinforced concrete structures are in force in Ukraine and in the world. Simultaneous strengthening of the compressed and tensile zones has not been sufficiently studied. Therefore, further research of reinforced concrete elements, strengthened by modern and highly efficient materials, such as steel fiber concrete and composite materials, is of great theoretical and practical importance. The urgency of the study is due to the obvious need to improve the method of calculation of the reinforced concrete bending elements after simultaneously strengthening compressed and tensile zones.

3

Mathematical model of modified classical lamination theory for foam core sandwich composites

Kumar S.J. Amith, Kumar Ajith S.J.

Composites Theory and Practice

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2023

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R. 23, nr 4

220--225

EN

Elastic properties are important quantities in the modelling and analysis of sandwich composite structures. The stability of sandwich composites mainly depends on their elastic properties, which in turn depend on the elastic properties of its constituents namely, the core and face skin. Several models have been proposed to predict the elastic constants of core materials such as honeycomb and foam. A foam core may be open-cell foam or closed-cell foam. The present work is focused on the hexagonal cells of a honeycomb grid core and closed-cell polymer syntactic foam core. The honeycomb is considered to be orthotropic with nine independent elastic properties. However, the overall structural performance of the honeycomb core is mainly influenced only by out-of-plane elastic properties. On the other hand, the syntactic foam is considered to beisotropic with two independent elastic constants namely, the modulus of elasticity and Poisson’s ratio. The face skin material may be isotropic with two independent elastic constants or orthotropic with nine elastic constants under three-dimensional loading. The present work is focused on predicting the elastic properties of a honeycomb core, syntactic foam and a glass/epoxy composite using existing theoretical models. Thereafter, the elastic properties of the syntactic foam and glass/epoxy composite are later used to establish the elastic constants for syntactic foam core sandwich composites using modified classical lamination theory (MCLT). The results reveal that the reviewed theoretical models for the honeycomb core, syntactic foam, fiber-reinforced polymeric (FRP) glass/epoxy face skins and sandwich composites are validated by the experimental results.

4

FRP strengthening of AAC masonry walls - comparative analysis and discussion selected calculation methods

Kałuża Marta

Archives of Civil Engineering

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2023

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Vol. 69, nr 2

97--110

EN

The use of FRP materials as external reinforcement of masonry structures has been recognized as an effective and minimally invasive method of wall strengthening. The available literature and research reports confirm the positive effect of the strip-like arrangement of composites with a horizontal, diagonal and - as shown in the paper - vertical configuration. The problem here is the proper estimation of the benefits of such FRP reinforcement, namely determining the real increase in shear strength. The paper described selected calculation procedures that can be found in the available literature (proprietary solutions), as well as in the published guidelines for the design of masonry walls strengthening using FRP materials. The results of experimental tests of sheared masonry walls made of AAC blocks and strengthened using vertical strips of carbon and glass fibres are briefly presented. Finally, based on the presented formulae, the values of the theoretical shear force resulted from the FRP contribution were calculated and detailed discussed. The comparison of the experimental and theoretical shear forces showed that only one of the presented calculation methods gave a high agreement of the results for both carbon and glass sheets. In addition, it was noticed that in two cases the effects of strengthening - depending on the material used - drastically differed, which was not observed in the research.

PL

Zastosowanie materiałów FRP jako zewnętrznego zbrojenia konstrukcji murowanych jest skuteczną i mało inwazyjną metodą wzmacniania ścian. Dostępna literatura potwierdza pozytywny wpływ kompozytów układanych pasmowo, w konfiguracji poziomej, ukośnej i - jak pokazano w artykule - pionowej. Problemem jest tu właściwe oszacowanie korzyści płynących z takiego zbrojenia, a dokładniej, określenie rzeczywistego wzrostu nośności na ścinanie wzmocnionej ściany. W artykule opisano wybrane procedury obliczeniowe dostępne w literaturze (rozwiązania autorskie), a także w opublikowanych wytycznych do projektowania wzmocnień ścian murowanych materiałami FRP. Pokrótce przedstawiono też wyniki własnych badań laboratoryjnych ścian murowanych z bloczków AAC poddanych ścinaniu, które wzmocniono pionowymi pasami z włókien węglowych i szklanych. Ostatecznie, na podstawie przedstawionych wzorów, obliczono i szczegółowo omówiono wartości teoretycznej siły ścinającej wynikającej z udziału FRP. Porównanie doświadczalnych i teoretycznych sił ścinających wykazało, że tylko jedna z przedstawionych metod obliczeniowych pozwala na uzyskanie dobrej zgodności wyników zarówno dla pasm CFRP, jak i GFRP. Ponadto zauważono, że w dwóch przypadkach wartości siły ścinającej, w zależności od użytego materiału, znacząco się różniły, czego nie zaobserwowano w badaniach.

5

Effects of stirrup spacing on shear performance of hybrid composite beams produced by pultruded GFRP profile infilled with reinforced concrete

Özkılıç Yasin Onuralp, Gemi Lokman, Madenci Emrah, Aksoylu Ceyhun

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 1

art. no. e36, 2023

EN

Pultruded Glass Fiber-Reinforced Polymer (pultruded GFRP) composite produced by the pultrusion method has become popular in civil engineering applications due to its lightness, corrosion resistance and high strength. However, the use of the pultruded profile combining with reinforced concrete is still limited due to a lack of knowledge. Therefore, the behavior of the pultruded GFRP profile infilled with reinforced concrete beams (hybrid beams) is investigated. This study focused on the effects of stirrup spacing for the hybrid beams. Pursuant to this goal, a total of eight different beams were tested under four-point loading. One reference beam without the pultruded profile and seven hybrid beams having different stirrup spacings were considered. Moreover, the hybrid beams with and without stirrups were wrapped by unidirectional GFRP composite to investigate the effects of stirrup spacing on shear capacity of the beams strengthened by GFRP composite. The experimental findings revealed that tightening stirrups increased the load and energy dissipation capacities of the hybrid beams; however, it could not prevent brittle failure. On the other hand, wrapping hybrid beams with GFRP composite increased the load and energy dissipation capacities and also prevented brittle failure regardless of the presence of the stirrups. Therefore, it is strongly recommended that the unidirectional pultruded profiles should be strengthened with 90° GFRP wrapping to have ductile behavior.

6

Professional profile map as a powerful educational tool for architects and civil engineers

Dawczyński Szymon, Krzywoń Rafał, Mannsberger-Nindl Sigrid, Schwenk Sabine, Navarro Arsenio, Garcia Serafin, Hernandez Lorena, Lladró Maria, Balufo Isabel Maria, Kuzma Valentina, Palatinus Andreja, Damianou Eleni, Angelakopoulou Paraskevi

Architecture Civil Engineering Environment

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2023

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Vol. 16, no. 3

65--76

EN

The paper discusses the importance of the Professional Profile Map (PPM) in the context of architecture and civil engineering education. It acknowledges the dynamic nature of these fields due to technological advancements and evolving industry practices, emphasizing the need for professionals who possess practical skills in addition to academic knowledge. The PPM is introduced as a valuable tool that acts as a bridge between academia and industry by defining the essential knowledge, skills, and competencies (KSC) required for success in these professions. Furthermore, the paper discusses the role of the PPM in Erasmus+ projects, highlighting its ability to facilitate customization and adaptability in education. It encourages interdisciplinary collaboration, practical experience, and employability enhancement, aligning with the goals of Erasmus+ projects. A case study from the TAB4BUILDING project illustrates how the PPM was used to identify KSC related to the use of Fibre Reinforced Polymers (FRP) in construction. The PPM's role in harmonizing educational programs across different countries and promoting international collaboration is emphasized.

7

Influence of longitudinal composite reinforcement on the structural behavior of glued laminated timber with openings

Jończyk Damian, Blikharskyy Yaroslav

Zeszyty Naukowe Politechniki Częstochowskiej. Budownictwo

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2022

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Z. 28 (178)

21-26

PL

Drewno klejone warstwowo jest obecnie często wykorzystywane w budownictwie. Najczęściej z drewna klejonego warstwowo wykonywane są dźwigary nośne, w których często ze względów architektonicznych istnieje potrzeba wykonania otworów pod różnego rodzaju instalacje. Otwory te osłabiają sztywność. Coraz bardziej powszechnym rozwiązaniem jest wzmacnianie belek drewnianych podłużnymi elementami kompozytowymi. W artykule przeprowadzono obliczenia numeryczne analizujące wpływ podłużnego zbrojenia kompozytowego w formie prętów BFRP na ugięcie belek z drewna klejonego z otworami.

EN

Glued laminated timber is now often used in construction. Most often, glued laminated timber is used to make load-bearing beams, in which there is often a need for architectural reasons to make openings for various types of installations. These openings weaken the stiffness. An increasingly common solution is to reinforce wooden beams with longitudinal composite elements. The paper presents numerical calculations analyzing the influence of longitudinal composite reinforcement in the form of BFRP bars on the deflection of glued laminated timber beams with openings.

8

Poszerzenie mostu z wykorzystaniem konstrukcji z kompozytów FRP

Siwowski Tomasz, Kulpa Maciej, Rajchel Mateusz, Oboza Dariusz

Nowoczesne Budownictwo Inżynieryjne

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2022

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Nr 1

71--73

PL

Od kilku lat popularność mostowych konstrukcji z kompozytów FRP (fibre reinforced polymers) systematycznie w Polsce wzrasta. Głównym tego powodem są doskonale własności mechaniczne i wysoka trwałość kompozytów FRP, a także upowszechnienie metod kształtowania i projektowania mostów z kompozytów FRP.

9

Fire resistance of FRP strengthening concrete beams at elevated temperature using ABAQUS

Keong Ng Chee, Kadir Mariyana Aida Ab, Zuhan Nurizaty, Mastor Muhammad Najmi Mohamad Ali, Alel Mohd Nur Asmawisham

Archives of Civil Engineering

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2022

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Vol. 68, nr 2

105--123

EN

Mechanical properties of FRP such as strength and stiffness as well as the bonding interface between FRP and concrete will be badly deteriorated when exposed to high temperature. Furthermore, the effect of thickness of insulation with different type of concrete strength has not yet been studied elsewhere in numerical studies. Therefore, this study is to assess the thermal-structural behaviour of insulated FRP strengthened RC beam exposed to elevated temperature using ABAQUS. The proposed numerical model of 200×300 mm RC beam subjected to 2 hours standard fire curve (ISO 834) had been validated with the analytical solution. The validated numerical model then is used in parametric study to investigate the behaviour of fire damaged normal strength concrete (40 MPa) and high strength concrete (60 MPa) of RC beam strengthened with CFRP using various fire insulation thickness of 12.5 mm, 25 mm and 40 mm, respectively. The result of steel characteristic strength reduction factor is compared with analytical using 500°C Isotherm methods. The parametric studies indicated that the fire insulation layer is essential to provide fire protection to the CFRP strengthened RC beams when exposed to elevated temperature. The insulation layer thickness of 25 mm had been found to be the optimum thickness to be used as it is able to meet the criteria of temperature distribution and displacement requirement. In conclusion, the numerical model developed using ABAQUS in this study is to carry out assessment on the thermal-structural behaviour of the insulated CFRP-strengthened RC beams at elevated temperature.

10

Experimental investigation on the compressive behaviour of FRP‑confined rectangular concrete columns

de Diego Ana, Martínez Sonia, Castro Viviana Jacqueline, Echevarría Luis, Barroso Francisco Javier, Gutiérrez José Pedro

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 3

art. no. e131

EN

This paper presents a comprehensive experimental study on the behaviour of FRP-confined concrete in square and rectangular columns and focuses on some issues that might be addressed with a view to improving the predictive models. For this purpose, 31 prismatic concrete specimens with a height of 600 mm and low- and medium-strength concrete (20-35 MPa) were tested under centred compression. The parameters studied were the aspect ratio between the sides of the section (1, 1.5 and 2), the radius of curvature of the corners (20, 25 and 30 mm) and the number of carbon FRP layers applied. The experimental results included stress-strain curves of specimens and detailed information about the confined concrete strength and the axial and lateral strain achieved on the FRP jacket during the tests. The stress-strain response and ultimate condition are analysed, showing that FRP jacketing is an efficient technique for increasing the strength and strain capacity, but that confinement efficiency decreases as the aspect ratio of the section increases. In spite of such decrease, significant strength improvement was achieved for low-strength concrete in rectangular sections with aspect ratios of 1.5 (strength gain up to 81%), and even 2 (up to 36%). The axial strength of the tests was compared with the design criteria of four international guidelines, resulting in predictions that did not properly fit for rectangular sections. A predictive equation is proposed to assess the axial compressive strength of the FRP-confined concrete, which includes a better adjustment for the strain efficiency factor and the shape factor for rectangular columns.

11

Compressive performance of AFRP reinforced laminated bamboo stub columns

Hong Chaokun, Li Haitao, Yang Dong, Li Hang, Zhang Huizhong, Lorenzo Rodolfo

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 1

art. no. e31, 2022

EN

Engineered bamboo construction can be affected by natural defects, insects, corrosion, etc., which will result in damaging the mechanical properties of structural components. However, traditional reinforcement methods such as setting steel supports and increasing the cross-sectional area of components may cost a lot and cause a negative influence on the appearance of building. Many engineering practices and research works show that applying FRP (Fiber Reinforced Polymer/Fiber) sheet is an economical and efficient method for reinforcing and retrofitting building structures. Therefore, the compressive performance of AFRP (Aramid Fiber Reinforced Polymer/Fiber) reinforced laminated bamboo lumber (LBL) stub columns was studied in this paper. Through six groups (three replicates for each group) of stub columns with six different cloth ratios, the influence of AFRP on the failure pattern and mechanical properties of bamboo columns was explored. The test results showed that AFRP could effectively restrain the lateral deformation and improve the mechanical behavior of LBL columns. With the increase in cloth ratio, the ultimate strength and elastic modulus increased linearly in general, while the Poisson’s ratio gradually decreased. The reduced modulus of reinforced columns in the elastoplastic stage increased up to 161.31% compared with normal columns. Although the ductility of LBL columns laterally wrapped by AFRP was greatly improved, the initial stiffness, yield point and turning points between elastoplastic stage and plastic stage basically remained unchanged in contrast to unreinforced columns. Based on the test results, an empirical equation considering the cloth ratio was proposed to calculate the ultimate strength of AFRP reinforced LBL columns, using ‘Lam and Teng’ model. In addition, a simplified equation was also proposed to calculate the compressive strength of reinforced LBL columns derived from Mises yield criterion. The results of this work can be a reference to promote the application of strengthening and retrofitting engineered bamboo structure with FRP.

12

Review of analytical models for estimating the bearing capacity of wooden beams reinforced with fiber composites

Jończyk Damian, Rajczyk Marlena

Zeszyty Naukowe Politechniki Częstochowskiej. Budownictwo

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2021

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Z. 27 (177)

76-82

PL

Wykorzystanie kompozytów do wzmacniania konstrukcji drewnianych jest obecnie popularnym rozwiązaniem konstrukcyjnym. Pomimo popularności rozwiązania nadal brak przepisów normatywnych określających sposoby szacowania nośności elementów drewnianych wzmacnianych kompozytami. Możliwe jest wykorzystanie metod numerycznych, lecz jest to metoda stosunkowo pracochłonna. W artykule przedstawiono przegląd najbardziej popularnych metod analitycznych służących do szacowania nośności zbrojonych elementów drewnianych.

EN

The use of composites to strengthen wooden structures is currently a popular construction solution. Despite the popularity of the solution, there are still no normative regulations specifying the methods of estimating the load-bearing capacity of wooden elements reinforced with composites. It is possible to use numerical methods, but it is a relatively laborious method. Due to the lack of normative requirements, engineers designing composite beams must use the methods presented in the literature. The article presents an overview of the most popular analytical methods for estimating the load-bearing capacity of reinforced wooden elements.

13

A comparative numerical analysis of glued laminated timber beams reinforced with bars made of various materials

Jończyk Damian

Budownictwo o Zoptymalizowanym Potencjale Energetycznym

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2021

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Vol. 10 Nr 1

151--159

EN

The use of fibrous composites to reinforce various structures is an increasingly common practice in construction. Wooden structures are commonly reinforced with composite materials. However, due to the lack of standard regulations for the design of reinforcements with the use of composites, many structural calculations are made in numerical analysis programs using the Finite Element Method (FEM). The article presents numerical calculations of glued laminated timber beams reinforced with various composite rods made using basalt, aramid, glass and carbon fibers. The stiffnesses and the normal stress distributions of the reinforced beam and the comparative, unreinforced beam were compared. The most effective reinforcement found uses carbon CFRP rods.

14

Shear strength testing of basalt-, hybrid-, and nano-hybrid fibre-reinforced polymer bars

Protchenko Kostiantyn, Zayoud Fares, Urbański Marek

Archives of Civil Engineering

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2021

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Vol. 67, nr 2

323--336

EN

Over the past decades, using of sustainable materials in construction is a challenging issue, thus Fibre Reinforced Polymers (FRP) took the attention of civil and structural engineers for its lightweight and high-strength properties. The paper describes the results of the shear strength testing of three different types of bars: (i) basalt-FRP (BFRP), (ii) hybrid FRP with carbon and basalt fibres (HFRP) and (iii) nano-hybrid FRP (nHFRP), with modification of the epoxy matrix of the bar. The hybridization of carbon and basalt fibres lead to more costefficient alternative than Carbon FRP (CFRP) bars and more sustainable alternative than Basalt FRP (BFRP) bars. The BFRP, HFRP and nHFRP bars with different diameters ranging from Ø4 to Ø18 mm were subjected to shear strength testing in order to investigate mechanical properties and the destruction mechanism of the bars. Obtained results display a slight downward trend as the bar diameter increase, which is the most noticeable for HFRP bars. In most of the cases, BFRP bars were characterized by greater shear deformation and less shear strength compared to HFRP and nHFRP bars. Performed testing may contribute to comprehensive understanding of the mechanical behavior of those types of FRP bars.

PL

W ostatnich dziesięcioleciach coraz większą rolę odgrywa zastosowanie zrównoważonych materiałów w budownictwie. Dlatego pręty kompozytowe Fibre-Reinforced Polymers (FRP) zwróciły uwagę inżynierów budownictwa ze względu na szereg zalet takich jak: zwiększoną trwałość, pełny recykling, odporność na korozję, mały ciężar i wysoką wytrzymałość. W artykule opisano wyniki badań wytrzymałości na ścinanie trzech typów prętów kompozytowych: (i) złożonych z włókien bazaltowych (BFRP) i matrycy epoksydowej, (ii) hybrydowych - wykonanych z włókien bazaltowych z dodatkiem włókien węglowych oraz matrycy epoksydowej (HFRP) a także (iii) nano-hybrydowych (nHFRP), złożonych z włókien bazaltowych i węglowych z udziałem zmodyfikowanej matrycy epoksydowej z dodatkiem nanokrzemionki. Pręty HFRP i nHFRP są znacznie tańsze niż pręty wykonane wyłącznie z włókien węglowych Carbon FRP (CFRP) a jednocześnie znacznie bardziej sztywne w porównaniu do prętów wykonanych wyłącznie z włókien bazaltowych FRP (BFRP). Pręty BFRP, HFRP i nHFRP o średnicach w 6, 8 , 10 ,12, 14, 18 mm poddano badaniom wytrzymałości na ścinanie w celu określenia właściwości mechanicznych oraz mechanizmu zniszczenia. Uzyskane wyniki wykazują niewielką tendencję spadkową wytrzymałości na ścinanie wraz ze wzrostem średnicy pręta, co jest najbardziej zauważalne w przypadku prętów HFRP. W większości przypadków pręty BFRP charakteryzowały się większym odkształceniem na ścinanie i mniejszą wytrzymałością na ścinanie w porównaniu z prętami z HFRP i nHFRP. Przeprowadzone testy mogą przyczynić się do pełnego zrozumienia mechanicznego zachowania się tych typów prętów FRP.

15

FRP bridges in Poland: state of practice

Siwowski Tomasz, Zobel Henryk, Al-Khafaji Thakaa, Karwowski Wojciech

Archives of Civil Engineering

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2021

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Vol. 67, nr 3

5--27

EN

The state of the art in the field of composite polymer bridges in Poland is presented below. Such bridges were built from 1999. Some of them are fully composite polymer structure. Others are developed as hybrid structure. There are two kind of structures: steel girders with FRP deck and FRP girders with concrete deck. Different production methods of FRP elements were used: pultrusion and infusion. Some bridges are the result of research programs, but there are also some commercial projects. Also, the short application history of FRP bridges all over the world is presented and material properties of the construction material are given in the paper. Those materials are much more lighter than steel or concrete. Low weight of FRP materials is an advantage but also disadvantage. It is good from structural and economical point of view because the dimensions of girders, piers and foundation will be smaller. From opposite side to light structure could cause problems related to response of structure against dynamic actions. As a final result the fatigue strength and durability will be reduced. Of course, the high cost of FRP (CFRP especially) limits at the moment range of application. The presented in the paper bridge structures show that despite of mentioned above problems they are now in good conditions and their future life looks optimistic. It could be supposed that modification and/or development of FRP production technologies more better utilizing their properties will create more elegant and useful bridges.

PL

W ciągu ostatnich lat przed mostowcami otworzyły się nowe możliwości. Dzięki lekkim, a przy tym bardziej wytrzymałym i trwalszym materiałom mogą oni zbliżyć się do granic nieosiągalnych dla materiałów tradycyjnych. Materiały te - polimery wzmacniane włóknami (FRP - z ang. Fiber Reinforcement Polymers) - do tej pory stosowane były z powodzeniem w lotnictwie, przemyśle kosmicznym, przy produkcji samochodów i łodzi. Dzięki niskiemu ciężarowi własnemu pozwalały na polepszenie osiągów oraz oszczędność paliwa. Bodźcem ograniczającym dość znacząco zastosowanie polimerów w innych dziedzinach była ich cena - wyższa od cen innych materiałów (np. metali) oraz wymagania odnośnie technologii układania i obrabiania. Kompozyty polimerowe (FRP) ze względu na swoje korzystne właściwości znajdują coraz szersze zastosowanie w mostownictwie. Materiały te, w przeciwieństwie do materiałów tradycyjnych odznaczają się małym ciężarem własnym, dużą wytrzymałością, odpornością korozyjną (zwłaszcza na sól). Obawy przed zastosowaniem FRP wiąże się przede wszystkim z brakiem doświadczeń, jeśli chodzi o trwałość tego materiału i wysokim kosztem (zwłaszcza włókien węglowych). Zaprezentowane w artykule rozwiązania konstrukcyjne dowodzą, że pomimo różnych ograniczeń technicznych i środowiskowych oraz komunikacyjnych sprawdzają się podczas eksploatacji. Należy przypuszczać, że po nabraniu pewności co do trwałości kompozytów polimerowych i opracowaniu nowych kształtów profili oraz ich połączeń, a także modyfikacji istniejących technologii produkcji lub wymyślenia nowych jeszcze lepiej wykorzystujących właściwości tych materiałów mosty z nich wykonane wpiszą się na stałe w polski krajobraz.

16

Rehabilitation of RC flexural members in shear with externally bonded fiber-reinforced polymer composites: present status and future need

Kar Swapnasarit, Biswal K. C.

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 3

752--775

EN

The present study gives an up-to-date, state-of-the-art review of the application of fiber-reinforced polymer (FRP) composites as an external shear strengthening material for reinforced concrete (RC) flexural members. Based on the critical review of more than a hundred experimental studies, this study discusses the influence of different parameters on the shear behavior of FRP strengthened RC beams. In addition, the present study discusses some of the widely used existing design guidelines for the prediction of the shear contribution of FRP composites. Along with these, this study also briefly discourses the application of numerical methods and soft-computing tools in the field of rehabilitation of shear-deficient RC flexural members using EB-FRP composites. Based on the parametric investigation, the current study empowers readers to recognize the existing gaps in the literature that should be examined in the future. Finally, the article concludes by summarizing key points of the shear strengthening of RC beams comprising FRP composites.

17

Kompozyty FRP w branży mostowej

Kwiecień Paweł

Mosty

|

2020

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nr 3

22

18

Seismic strengthening of nonductile bridge piers using low-cost glass fiber polymers

Rodsin K., Hussain Q., Joyklad P., Nawaz A., Fazliani H.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2020

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Vol. 68, nr 6

1457--1470

EN

Several recent earthquakes have indicated that the design and construction of bridges based on former seismic design provisions are susceptible to fatal collapse triggered by the failure of reinforced concrete columns. This paper incorporates an experimental investigation into the seismic response of nonductile bridge piers strengthened with low-cost glass fiber reinforced polymers (LC-GFRP). Three full-scale bridge piers were tested under lateral cyclic loading. A control bridge pier was tested in the as-built condition and the other two bridge piers were experimentally tested after strengthening them with LC-GFRP jacketing. The LC-GFRP strengthening was performed using two different configurations. The control bridge pier showed poor seismic response with the progress of significant cracks at very low drift levels. Test results indicated the efficiency of the tested strengthening configurations to improve the performance of the strengthened bridge piers including crack pattern, yield, and ultimate cyclic load capacities, ductility ratio, dissipated energy capacity, initial stiffness degradation, and fracture mode.

19

Mechanical and morphological characterization of discarded fishnet/glass fiber reinforced polyester composite

Monivarman P., Nagarajan V. A., Raj F. M.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2020

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Vol. 68, nr 6

1385--1391

EN

The present work focuses on the fabrication of glass fiber and multifilament discarded fishnet nylon fiber polymer composites with four different fiber compositions. Composites are molded by means of simple hand lay-up methodology with dissimilar layers of the fiber mat. The mechanical characterization (tensile and impact) and thermal analysis of composites have to be investigated. Among the different patterns, hybrid composites reflected better tensile and impact properties as compared to the conventional materials. Morphological characterization was carried out to figure out the de-bonding of fiber/matrix adhesion characteristics of fractured face of tensile testing samples. The result suggests the potential for reuse of discarded fishnet, which constitutes a better alternative for structural work and for possible applications to be used to develop added-value products.

20

Wpływ zbrojenia niemetalicznego na nośność i odkształcalność belek z betonu zbrojonego

Korentz Jacek

Builder

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2020

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R.24, nr 4

104--106

PL

W konstrukcjach z betonu coraz częściej stosuje się pręty kompozytowe FRP (ang. Fiber Reinforced Polimer) wykonane z różnych materiałów. Właściwości wytrzymałościowe dostępnych na rynku prętów kompozytowych są bardzo zróżnicowane. Pręty kompozytowe mają bardzo wysoką wytrzymałość, moduł sprężystości większości z nich jest niski. Pręty te nie mają cech plastycznych, ich zniszczenie następuje w sposób nagły. Dlatego zachowanie się belek zbrojonych prętami kompozytowymi odbiega od znanego zachowania się belek ze zbrojeniem stalowym; nośność na zginanie i odkształcalność tych belek są bardzo zróżnicowane. W artykule przeanalizowano wpływ rodzaju zastosowanego zbrojenia w belkach na ich nośność i odkształcalność. Belki ze zbrojeniem niemetalicznym w stosunku do belek ze zbrojeniem stalowym charakteryzują się większą nośnością i mniejszą sztywnością, a tym samym większymi ugięciami.

EN

Reinforced concrete constructions use nonmetallic rebar (FRP) made of various materials. The strength properties of FRP rebar available on the market are very diverse. FRP rebar have very high strength, the modulus of elasticity of most of them is low. These rebar have no plastic features, their failure occurs suddenly. Therefore, the behavior of reinforced beams with FRP rebar differs from the known behavior of steel reinforced beams; the flexural strength and deformability of these beams vary widely. The article analyzes the impact of the type of FRP rebar used in beams on their load-bearing capacity and deformability. Beams behind non-metallic reinforcement in relation to steel-reinforced beams are characterized by higher load capacity and lower stiffness, and thus greater deflections.