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1

The behaviour of R.C. beams patch-repaired and strengthened with CFRP strips subjected to impact loading

Moyo Pilate, Habimana Philbert, Kabani Matongo

Materiały Budowlane

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2024

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nr 7

1--4

EN

This paper presents an experimental investigation of the structural behaviour of reinforced concrete (R.C.) beams, patch-repaired with a cementitious grout and strengthened with carbon fibre reinforced polymer (CFRP) strips subjected to impact loading. The results of this study show that strengthening patch-repaired R.C. beams subjected to impact loading using CFRP plates, restores the load-carrying capacity of the beams. The strengthened beams exhibited ductile behaviour with no debonding between the patch repair and the substrate concrete. The primary failure mode of the strengthened beams was intermediate crack (I.C.) debonding. In addition, the beams with longer patch length exhibited higher flexural strength.

PL

Artykuł przedstawia eksperymentalne badanie zachowania belek żelbetowych, naprawionych miejscowo za pomocą zaprawy cementowej i wzmocnionych taśmami z polimerów zbrojonych włóknem węglowym (CFRP), poddanych obciążeniom udarowym. Wyniki tego badania pokazują, że wzmocnienie miejscowo naprawionych belek żelbetowych za pomocą płyt CFRP przywraca nośność tych belek, poddanych obciążeniom udarowym. Wzmocnione belki wykazywały zachowanie plastyczne bez odspajania się naprawy miejscowej od betonowego podłoża. Głównym trybem zniszczenia wzmocnionych belek było odspajanie się pęknięć pośrednich. Dodatkowo, belki z dłuższą strefą naprawy wykazywały większą wytrzymałość na zginanie niż z krótszą.

2

Rysy, pęknięcia w betonowych nawierzchniach drogowych (część 1)

Litwinowicz Andrzej, Rechnio Mariusz

Budownictwo, Technologie, Architektura

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2024

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nr 2

38--42

3

Efektywna sztywność pękniętego szkła laminowanego

Galuppi Laura, Royer-Carfagni Gianni

Świat Szkła

|

2023

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R. 28, nr 4

37--41

4

Przekrycia na bazie drewna

Kram Dorota, Śliwa-Wieczorek Klaudia

Inżynier Budownictwa

|

2023

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nr 1

36--42

5

The influence of a polyurea coating on bent reinforced concrete beams with various reinforcement ratios

Szafran Jacek, Matusiak Artur, Rzeszut Katarzyna, Jankowiak Iwona

Bulletin of the Polish Academy of Sciences. Technical Sciences

|

2023

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Vol. 71, nr 1

art. no. e144579

EN

“Polyurea coatings as a possible structural reinforcement system” is a research project aimed at exploring possible applications of polyurea coatings for improving structural performance (including steel, concrete, wooden and other structures used in the construction industry). As part of the project, this paper focuses on evaluating the performance of bent reinforced concrete (RC) beams covered with a polyurea coating system. Easy polyurea application and its numerous advantages can prove very useful when existing RC structural elements are repaired or retrofitted. Laboratory tests of three types of RC beams with three different longitudinal reinforcement ratios were performed for the purposes of this paper. The tests were designed to determine the bending strength, performance and cracking patterns of the coated RC beams. In addition, a theoretical model was developed to predict the impact of the polyurea coating on the bending strength of the RC beams. On this basis, the effect of the coating on the bending strength and the performance of the coated beams at the ultimate limit state (ULS) was examined and analyzed. The results showed that the use of the polyurea coating has a positive impact on the cracking state of the RC beams subject to bending and little effect on their bending strength.

6

Experimental study of the fracture of CT specimens printed in PLA as a function of the raster width

Aourik O., Othmani M., Chouaf A.

Archives of Materials Science and Engineering

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2023

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Vol. 122, nr 2

78--85

EN

Purpose: The FDM (Fused Deposition Modelling) additive manufacturing process is characterised by a large number of process variables that determine the mechanical properties and quality of the manufactured parts. When printing layer by layer, the filaments constituting the layer are welded on the one hand between them in the same layer and on the other hand between the superimposed layers, this welding develops on the contact surfaces (raster width) along the deposited filaments. The quality of this welding determines the resistance to crack propagation between filaments and between layers. This article aims to study the effect of the width of the raster on the resistance to crack propagation in a structure obtained by FDM. Design/methodology/approach: We have developed an experimental approach from CT specimens to determine the tensile strength of polylactic acid (PLA) polymers, considering the J-Integral method. And given the complexity of the problem, three cases of raster width (l=0.42 mm, l=0.56 mm and l=0.68 mm) have been treated. Findings: According to the results obtained (J, ∆a), the resistance to crack propagation in the parts printed by FDM seems to be better when the width of the filament is small. Indeed, the energy necessary to break the specimen is relatively greater than in the case of a larger width. This finding was confirmed by comparing the values of J for a given advancement of the crack for the three cases studied. Research limitations/implications: In order to present an exhaustive study, we focused on the effect of raster widths (including 0.42 mm, 0.56 mm to 0.68 mm) on the crack propagation of printed PLA. This study is in progress for other printing parameters. To highlight the cracking mechanisms, microscopic observations will be developed in greater depth at the SEM. Practical implications: Our analysis can be used as decision support in the design of FDM parts. In effect, we can choose the raster width that would provide the resistance to crack propagation desired for a functional part. Originality/value: In this article, we analysed the damage mechanism of CT specimens printed by FDM. This subject represents a new direction for many lines of research. For our study, we used the J-Integral theoretical approach to study the fracture behaviour of these parts by determining the resistance curves (J-∆a).

7

Uniaxial compression test and numerical simulation of rock-like specimen with T-Shaped cracks

Liangxiao Xiong, Chen Haijun, Xu Zhongyuan, Hu Deye

Archives of Civil Engineering

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2023

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Vol. 69, nr 2

227--244

EN

In this study, the uniaxial compression test and PFC2D numerical simulation were carried out on the artificial rock specimen with T-shaped prefabricated fractures. The effects of the lengths l1, l2 of the main fractures, the length l3 of the secondary fracture, and the angle β between the secondary fracture and the loading direction on the uniaxial compressive strength and crack evolution law of specimen were studied. The research results show that the change of l1, l2 and β has obvious effect on the compressive strength and crack growth of the specimen, but the change of l3 has little effect on the compressive strength of the specimen. When l3 = 40 mm and l1 ≠ l2, the angle β influences on the crack propagation and failure mode of the specimen.

8

Dynamic stability of a cracked pipe conveying fluid and resting on a Pasternak elastic foundation

Lolov Dimitar, Lilkova-Markova Svetlana

Zeszyty Naukowe. Transport / Politechnika Śląska

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2022

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z. 117

103--113

EN

Pipeline transport is used worldwide in many sectors of the economy. Its main advantages are continuity of transport, large transportation volumes, small energy consumption, safety, reliability and high environmental benefits. However, the safety problems of pipes attract much interest in science and industry. This paper deals with a cracked pipe with a static scheme of a simply supported beam. It rests along its entire length on a Pasternak elastic foundation. The flowing fluid is considered non-compressible and heavy. The Galerkin method is employed to approach the problem numerically. Conclusions are drawn based on the influence of the crack and the parameters of the Pasternak elastic foundation on the critical flow velocity of the fluid.

9

Uszkodzenie i wzmocnienie prefabrykowanych przestawnych ścian oporowych w magazynie materiałów sypkich

Kamiński Mieczysław, Drzazga Michał, Kaźmierowski Maciej, Drzazga Marek

Przegląd Budowlany

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2022

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R. 93, nr 9-10

20--23

PL

W artykule opisano studium przypadku uszkodzenia prefabrykowanej, przestawnej ściany oporowej o konstrukcji żelbetowej (dolny fragment) i stalowej (górny fragment). Omówiono przyczyny oraz zakres uszkodzeń. Przeprowadzono analizy numeryczne metodą elementów skończonych (MES) w zakresie wybranych elementów konstrukcyjnych ściany w stanie istniejącym oraz po wykonaniu wzmocnienia. Przedstawiono najważniejsze elementy projektu wzmocnienia wykonanego w programie opartym o technologię BIM.

EN

This paper describes a case study of damage to a precast, repositionable retaining wall made of reinforced concrete (lower section) and steel (upper section). The causes and extent of damage are discussed. Numerical analyses using the finite element method (FEM) of selected structural elements in the existing state and after strengthening were carried out. The most important elements of the wall strengthening project made in a BIM-based software are presented.

10

Experimental and Simulation Tests of the 1 MN Screw Coupling

Kowalczyk Dariusz, Aniszewicz Andrzej

Problemy Kolejnictwa

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2022

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Z. 194

97--102

EN

The article describes the requirements that screw couplings must meet before they can be put into service. In the paper, the results of fatigue testing simulating a 30-year service life of a screw coupling are presented, as well as the results of CT and Nondestructive Testing, NDT, non-destructive magnetic particle inspection, and then, the test results are compared with the results obtained with the application of Finite Element Method, FEM.

11

Badania kolejowych podkładów strunobetonowych z zastosowaniem emisji akustycznej

Kowalczyk Dariusz

Problemy Kolejnictwa

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2022

|

Z. 197

67--80

PL

W artykule opisano badania podkładów strunobetonowych wykonywanych według metody określonej wymaganiami norm europejskich PN-EN 13230 (Kolejnictwo − Tor − Podkłady i podrozjazdnice betonowe) i WTWiO oraz zastosowano dodatkową metodę pomiarową – emisji akustycznej (AE). Celem przeprowadzonych badań metodą emisji akustycznej była weryfikacja uzyskanych wyników innymi metodami badawczymi opisanymi w normie. Zastosowanie tej metody w badaniach podkładów umożliwia uzyskanie precyzyjnych danych z przebiegu próby obciążenia podkładu i wyznaczenie charakterystycznych parametrów na podstawie rejestrowanych sygnałów AE. Ze względu na różnorodność produkowanych konstrukcji podkładów strubobetonowych i rozwój produktów w tym obszarze: podkłady drewniane, podkłady kompozytowe, stalowe (tzw. Y), zastosowanie metody emisji akustycznej w badaniach będzie dobrym wsparciem i będzie umożliwiało właściwą oceną tych elementów drogi kolejowej.

12

Badania doświadczalne i symulacyjne sprzęgu śrubowego 1 MN

Kowalczyk Dariusz, Aniszewicz Andrzej

Problemy Kolejnictwa

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2022

|

Z. 194

33--38

PL

W artykule opisano wymagania, dotyczące sprzęgów śrubowych, obowiązujące przed wprowadzeniem ich do eksploatacji. Przedstawiono wyniki badań zmęczeniowych symulujących 30-letni okres użytkowania sprzęgu śrubowego, wyniki badań metodą tomografii komputerowej i NDT (ang. Nondestructive Testing), nieniszczącą metodą magnetyczno-proszkową, następnie porównano wyniki badań z wynikami obliczonymi metodą elementów skończonych MES (ang. Finite Element Method - FEM).

13

Reinforcement of cracked hollow-core slabs during the construction of the building

Szeląg Romuald

Inżynieria Bezpieczeństwa Obiektów Antropogenicznych

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2022

|

Nr 4

54--62

EN

During the implementation of investment processes with the use of ready-made prefabricated elements, undesirable situations may occur that cause scratches, excessive deflections or damage. This is due to the fact that defects occur during transport, storage or incorrect loading of the elements. The conducted tests and technical assessments often allow the use of built-in elements, however, under the conditions of the need to make their reinforcements. This may be due to the scale of damage or defects made during molding and, as a consequence, the implementation of prefabricated elements with too low load capacity. Taking action each time should allow for the implementation of reinforcements of the elements, limiting the need to dismantle them, which would result in their irretrievable destruction. The implementation of reinforcements allows to reduce the generation of waste from new elements and allows for the proper management of already produced prefabricated elements. Used elements with reinforcements should be subject to technical inspection in the same periods as other structural elements. Proper implementation of repairs allows for the final effect to be similar to the parameters of elements free of technical defects. Due to the existing problem of damage to new elements of prefabricated channel ceilings, solutions have been developed that can be used to reinforce the elements without the need to dismantle them from the places of installation, while reducing the time spent on the process.

14

Numerical analysis of interfacial debonding of metal/ceramic bimaterial using FEM

Ramdoum Sara, Serier Boualem, Feo Luciano

Composites Theory and Practice

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2022

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R. 22, nr 3

130--134

EN

The bimaterials applied in various fields of industry consist mainly of ceramics and metal. Their damage is mainly due to the presence of residual stresses generated during their manufacture. The damaged area is closely related to the high production temperature. The aim of this study is to analyze the effect of these factors on the behavior of an interfacial and subinterfacial crack in the volume of alumina material. This behavior is studied in terms of variation of the stress intensity factor (SIF) in Modes I, II and III. A study by means of the finite element method (FEM) was carried out. This work demonstrates that the risk of sudden propagation of these cracks is all the more probable when the bimaterial is produced at high temperatures. The elastoplastic behavior of the metal considerably minimizes this risk by plasticizing the metal, which allows strong relaxation of the residual stresses.

15

Study of rock fracture under blast loading

Baranowski Paweł, Kucewicz Michał, Pytlik Mateusz, Małachowski Jerzy

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2022

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Vol. 70, nr 5

art. no. e141723

EN

A study of dolomite rock material failure using a simple small-scale blast setup is presented. Laboratory tests were conducted using disc specimens drilled with a borehole in the center. A detonation cord and a blasting cap were fitted inside the borehole to induce cracking and fracturing of the specimens. The specimens were inserted between two steel plates, which were compressed against the specimen using bolt screws. Prior to testing, the most suitable screw torque for constraining the vertical displacement of the specimen surfaces without compressing the specimen was selected based on numerical simulations. Then, the experimental tests with the blasting cap were simulated using the Johnson–Holmquist II (JH-2) material model, and the properties of the blasting cap were determined and verified in two special tests with a lead specimen. Possessing the validated model, the influence of specimen thickness on the cracking patterns was finally analyzed. This paper presents a relatively easy method for studying rock material behavior under blast loading and for validating the numerical and constitutive models used for rock simulations.

16

Research corrosion propagation time of reinforced concrete structures considering load influence

Dinh Dao Van, Hung Tran Viet

Archives of Civil Engineering

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2022

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Vol. 68, nr 2

563--576

EN

Prediction of propagation time of corrosion is a key element in evaluating the service life of corroded reinforced concrete (RC) structures. Corroded steel products often expand in volume and thus generate tensile stress in the concrete cover. When this tensile stress exceeds the tensile strength of the concrete, cracking occurs. The tensile stresses in concrete due to corrosion are usually perpendicular to the longitudinal axis of the reinforcement. In the reinforced concrete beams, tensile stresses in concrete due to bending is perpendicular to the longitudinal direction of stirrups. In the reinforced concrete slabs, the tensile stresses in concrete due to bending is also perpendicular to the axis of longitudinal reinforcement subjected to bending in the other direction. In such cases, the tensile stresses in concrete due to corrosion of reinforcement has the same direction as the tensile stress caused by bending. When the load-induced stress in the concrete has the same direction as that of the corrosion-induced stress, cracks will likely appear more quickly and vice versa. The main objective of this paper is to build a predictive model of corrosion propagation time taking into account: (1) the effect of stresses due to load; (2) the change of corrosion current density. The model was implemented on Matlab software. The results show the influence of the load, and other parameters on the corrosion propagation stage, when considering the end of this corrosion propagation stage is cracking of concrete cover.

17

Nonlinear modelling of a bridge: A case study-based damage evaluation and proposal of Structural Health Monitoring (SHM) system

Fawad Muhammad, Koris Kalman, Salamak Marek, Gerges Michael, Bednarski Lukasz, Sienko Rafal

Archives of Civil Engineering

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2022

|

Vol. 68, nr 3

569--584

EN

Monitoring and structural health assessment are the primary requirements for performance evaluation of damaged bridges. This paper highlights the case-study of a damaged Reinforced Concrete (RC) bridge structure by considering the outcomes of destructive testing, Non-Destructive Testing (NDT) evaluations, static and 3D non-linear analysis methods. Finite element (FE) modelling of this structure is being done using the material properties extracted by the in-situ testing. Analysis is carried out to evaluate the bridge damage based on the data recorded after the static linear (AXIS VM software) and 3D non-linear analysis (ATENA 3D software). Extensive concrete cracking and high value of crack width are found to be the major problems, leading to lowering the performance of the bridge. As a solution, this paper proposes a proper Structural Health Monitoring (SHM) system, that will extend the life cycle of the bridge with minimal repair costs and reduced risk of failure. This system is based on the installation of three different types of sensors: Liquid Levelling sensors (LLS) for measurement of vertical displacement, Distributed Fiber Optic Sensors (DFOS) for crack monitoring, and Weigh in Motion (WIM) devices for monitoring of moving loads on bridge.

18

Experimental study on dynamic stability of rubber-cement composites by SHPB and high-speed slicing

Yang Rongzhou, Xu Ying, Chen Pei Yuan

Archives of Civil Engineering

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2022

|

Vol. 68, nr 1

319--334

EN

Improper disposal of waste tires will not only bring environmental impact and safety risks but also cause a serious waste of resources. In the field of civil engineering materials, waste tire particles are used as a substitute for non-renewable aggregates to produce flexible rubber-cement composites (RCC). To explore the high-speed slicing stability of RCC, this test took normal cement mortar (NCM) and rubber cement mortar (RCM) as research objects. The SHPB tests with the same impact energy level and the high-speed slicing tests with a slice thickness range of about 1.4 mm ~ 4.4 mm were carried out. The results showed that NCM and RCM showed different stability differences in the process of high-speed slicing. In the case of ensuring the integrity of the slice, the minimum thickness of the slice can be better decreased with the increase of the rubber content. Finally, from the perspectives of split Hopkinson pressure bar (SHPB) test results and mesoscopic structure states, the essential reason for ensuring the stability of high-speed slicing lied in the improvement of rubber particles (dominant role) and pores on material deformation and flexible energy dissipation.

19

Influences of stress states and loading directions on the anisotropic fracture of magnesium alloy AZ31B sheet under tension-dominated forming conditions

Qian Lingyun, Xu Sinuo, Li Heng, Zhou Yuwei, Sun Chaoyang, Ma Tengyun

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 4

art. no. e213, 2022

EN

The crystallographic textures of metal sheet induced by the rolling process cause its anisotropic fracture behavior via plasticity anisotropy. This research aimed to characterize the anisotropic fracture behavior of magnesium alloy AZ31B sheet during the conventional tension-dominated forming conditions. Four specimens with different shapes were designed to cover diverse stress states, and were respectively tension-tested to fracture along the rolling direction (RD), diagonal direction (DD), and transverse direction (TD) of rolled sheet. Almost all specimens failed in the shear fracture mode with slight necking localization. The distinct differences among load response, strain distribution as well fracture strain for three directions revealed the severe anisotropic fracture characteristic. To characterize the fracture anisotropy, the isotropic modified Mohr–Coulomb (MMC) fracture criterion was revised into an anisotropic one by considering the effect of loading direction. The updated unified fracture model together with the Yld2000-3d anisotropic yield function had better performances in describing load responses of tension tests for scaled modified compact-tension (SMCT) specimens under three loading directions, especially blindly predicting their crack locations. Three SMCT specimens all failed due to the tension-dominated stress state with the stress triaxiality higher than 1/3. As a comparison, the isotropic MMC model separately calibrated by tests along the RD, DD, and TD can only predict the fracture behavior of SMCT specimen in the corresponding loading direction, but it failed to judge the fracture features of other two directions.

20

Influence of weak inclusions on the cracking behavior of a jointed rock mass containing an opening: insights from DIC-based approaches

Liu Xianghua, Zhang Ke, Liu Wenlian, Xie Jianbin

Archives of Civil and Mechanical Engineering

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2022

|

Vol. 22, no. 4

art. no. e184, 2022

EN

To gain deep insights into the reinforcement effect of weak inclusions on jointed rock masses containing an opening, natural sandstone specimens containing multiple non-persistent joints and an opening were prepared, and two different cases, unfilled and filled openings, were considered. Digital image correlation (DIC) was applied to characterize the deformation fields of specimens during loading. Two measures extended from the DIC, the displacement vector and multivariate measure of strain dispersion, were proposed to identify and quantitatively analyze the cracking mechanism. Weak inclusions were found to improve the mechanical properties. The displacement vector fields around the newly formed cracks were calculated, and then, four types of cracks were recognized: direct tensile cracks, relative tensile cracks, shear cracks, and mixed cracks. Based on the fracture nature of cracks, nine types of crack coalescence among joints and six categories between openings and joints were summarized. The influence of weak inclusions on the cracking behavior of jointed sandstones was further clarified. Many more cracks were detected in the specimens containing a filled opening, which was validated by the fractal dimensions of the ultimate fracture surfaces. The differentiation rate of the effective variance (DREV) was defined to describe the dispersion of full-field strain data. The DREV was extremely close to 0 at the initial compacting and elastic deformation stage and then exhibited anomalous responses to cracking events. The first peak in the DREV–strain curve represents crack initiation, which can be regarded as a precursor.