Articoli di riviste: "Reinforced concrete construction Testing"

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Rybak, Roman. "EXPERIMENTAL TESTING METHODOLOGY OF STRESS-STRAIN STATE OF THE REINFORCED CONCRETE PIPE WITH STRENGTHENING". Theory and Building Practice 2022, n. 2 (20 dicembre 2022): 36–43. http://dx.doi.org/10.23939/jtbp2022.02.036.

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Reinforced concrete pipes are exposed to environmental influences during the entire period of their operation. As a result, defects and damage appear and reduce durability and bearing capacity. In this regard, there is a need to repair and strengthen them. In order to assess the effectiveness of strengthening reinforced concrete pipes, it is necessary to get data about deformations that appeared as a result of the loads on the reinforced concrete pipe. The method for conducting experimental studies of the deformed state of reinforced concrete pipes has been developed, and the main devices and means necessary for conducting experimental research in laboratory conditions have been selected. The obtained data of deformations appearance can be used to compare the effectiveness of various methods of strengthening reinforced concrete pipes and their improvement as well as to monitor technical condition and to predict the formation of defects.

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Burkovič, Kamil, Martina Smirakova e Pavlina Matečková. "Testing and Modelling of Concrete Pile Foundations". Key Engineering Materials 738 (giugno 2017): 287–97. http://dx.doi.org/10.4028/www.scientific.net/kem.738.287.

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Foundation of building on concrete piles is often used when it is necessary to carry the load into larger depth as by common foundation. Bearing capacity of piles or piled raft foundation is wide area to research. This paper deals with experimental load test of concrete pile and with their numerical modelling. Several types of foundation construction were tested and two kinds will be presented and compared in this paper - reinforced concrete foundation slab and raft foundation (made of reinforced concrete foundation slab supported by drilled reinforced concrete pilot). These types of foundation constructions were constructed as models, in a reduced scale, approx. 1:10. The size had to be adjusted due to limited capacity of the testing equipment and financial reasons. Except measuring of the foundation behaviour, there was also carried out measurement of the adjacent terrain.The aim of this paper is to compare the behaviour of rigid slab and the piled raft. The measurement results will be then compared with the results of numerical modelling.

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Davidyuk, Artem, e Igor Rumyantsev. "Quality control of high-performance concrete in high-rise construction during operation". MATEC Web of Conferences 170 (2018): 01035. http://dx.doi.org/10.1051/matecconf/201817001035.

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With onset of the XXI century, the demand for construction of high-rise buildings with the load-bearing framework made of high-performance cast-in-situ concrete has increased many-fold in the construction sector. Specific features of the high-performance concrete of bearing structures in the situation of real operation of high-rise buildings are continuously studied by scientists and specialists all over the world, and regulatory and methodological documents are being complemented and adjusted. High-performance concretes and structures made of them possess some specific features that should be taken into account in quality control. The methods of concrete inspection and concrete strength evaluation described in GOST 18105 “Concretes. Guidelines on Testing and Evaluation of Strength” and GOST 22690 “Concretes. Evaluation of Strength by Mechanic Non-Destructive Test Methods” were written when precast reinforced concrete was predominantly used in the construction sector and were limited to the functions of intra-factory quality control of reinforced concrete products. At present, instruments for non-destructive testing using indirect methods are usually calibrated with the help of local destructions, as a rule, a pull out or rib shear test. The said methods are in fact indirect since they indicate the force of destruction of the surface layer of a structure.

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Orlowsky, Jeanette, Markus Beßling e Vitalii Kryzhanovskyi. "Prospects for the Use of Textile-Reinforced Concrete in Buildings and Structures Maintenance". Buildings 13, n. 1 (10 gennaio 2023): 189. http://dx.doi.org/10.3390/buildings13010189.

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This paper discusses the state of the art in research on the use of textile-reinforced concretes in structural maintenance. Textile-reinforced concretes can be used in structural maintenance for various purposes, including the sealing and protection of the existing building structures, as well as for the strengthening of structures. The first-mentioned aspects are explained in this paper on the basis of example applications. A special focus is placed on the maintenance of heritage-protected structures. The development, characterization, and testing of a textile-reinforced concrete system for a heritage-protected structure are presented. Examples of the application of textile-reinforced concrete for strengthening highway pavements and masonry are also given. In particular, the possibility of adapting the textile-reinforced concrete repair material to the needs of the individual building is one advantage of this composite material.

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Zhang, Jianren, Hui Peng e C. S. Cai. "Destructive Testing of a Decommissioned Reinforced Concrete Bridge". Journal of Bridge Engineering 18, n. 6 (giugno 2013): 564–69. http://dx.doi.org/10.1061/(asce)be.1943-5592.0000408.

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Choi, Pangil, Lochana Poudyal, Fouzieh Rouzmehr e Moon Won. "Spalling in Continuously Reinforced Concrete Pavement in Texas". Transportation Research Record: Journal of the Transportation Research Board 2674, n. 11 (10 settembre 2020): 731–40. http://dx.doi.org/10.1177/0361198120948509.

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The performance of continuously reinforced concrete pavement (CRCP) in Texas has been quite satisfactory, primarily thanks to the continuous improvements in design and construction. However, severe spalling has been a major problem, and the Texas Department of Transportation (TxDOT) has sponsored several research projects since 1985 to identify solutions for this serious problem. Even though the research efforts were successful in identifying spalling mechanisms, developing a policy that TxDOT could easily implement has been a challenge. To develop a more practical solution to this problem, TxDOT initiated a research study, and the research efforts consisting of identifying CRCP projects with severe and no spalling, obtaining and conducting materials testing on concrete cores from those projects, analyzing the testing data, and performing theoretical analyses to validate the testing results. Among the material properties evaluated, the coefficient of thermal expansion (CTE) of concrete proved to have the best correlation with spalling. Detailed analyses of mechanistic behavior of concrete conducted with an object-oriented finite element program (OOF2) and commercial finite element program verified the reasonableness of the field-testing results. All concrete cores from CRCP with severe spalling had a CTE larger than 5.5 microstrains/°F, whereas no spalling was observed in concrete with a CTE less than that value. Based on this finding, TxDOT now requires the use of coarse aggregate that will produce concrete with a CTE of less than 5.5 microstrains/°F for CRCP construction. It is expected that this implementation will reduce the spalling in CRCP substantially.

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Belentsov, Yuri A., e Liliya F. Kazanskaya. "Non-destructive methods of concrete quality control as factor in reliability of concrete and reinforced concrete structures in transport facilities". Transportation Systems and Technology 4, n. 1 (15 marzo 2018): 058–67. http://dx.doi.org/10.17816/transsyst2018041058-067.

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Aim: The development of theory and practice of construction science leads to a need to enhance the basics of design, construction and operation of concrete and reinforced concrete structures. Despite significant progress, there is risk of collapse of different structures at various stages of their lifecycle. Current state of construction industry leads to a need to increase the quality and reliability of buildings and structures under construction. Methods: The authors have used methods of probabilistic forecasting in this work Results: The development of methods of construction materials control, particularly concrete and reinforced concrete, leads to a gradual implementation of non-destructive control methods. To assess the change of confidence and reliability coefficients of designed structures, the authors have substantiated the transition to probabilistic rationing of strength properties of concrete and reinforced concrete structures using classes. Also, the authors suggest implementation of non-destructive control methods. However, non-destructive control methods have a number of drawbacks, the key among these being the decrease of confidence coefficient while preparing a calibration curve, which drastically affects the results of quality control. It is possible to solve the problem by creating a set of control tests including both destructive and non-destructive quality control methods. This will provide systems for collecting testing information of high accuracy.

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Lindner, Marco, Konrad Vanselow, Sandra Gelbrich e Lothar Kroll. "Fibre-reinforced polymer stirrup for reinforcing concrete structures". Technologies for Lightweight Structures (TLS) 3, n. 1 (24 gennaio 2020): 17–24. http://dx.doi.org/10.21935/tls.v3i1.117.

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Fibre-plastic composites offer an interesting alternative to concrete reinforcement. In order to expandthe application spectrum of reinforcing elements in fibre composite construction, a new steel-free bracingsystem with reduced radii of curvature was developed. An improvement in load carrying capacity couldbe proven in extensive investigations based on international testing methods and verified by practicaltests. With the help of newly reinforced precast concrete elements from the area of waterways and trafficroutes, a high potential for lightweight construction and resource efficiency can be impressivelydemonstrated.

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Newtson, Craig M., Gaur P. Johnson e Brian T. Enomoto. "Fundamental Frequency Testing of Reinforced Concrete Beams". Journal of Performance of Constructed Facilities 20, n. 2 (maggio 2006): 196–200. http://dx.doi.org/10.1061/(asce)0887-3828(2006)20:2(196).

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Benmokrane, Brahim, Ehab El-Salakawy, Amr El-Ragaby e Sherif El-Gamal. "Performance evaluation of innovative concrete bridge deck slabs reinforced with fibre-reinforced-polymer bars". Canadian Journal of Civil Engineering 34, n. 3 (1 marzo 2007): 298–310. http://dx.doi.org/10.1139/l06-173.

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This paper presents the construction details, field testing, and analytical results of six innovative concrete bridges reinforced with fibre-reinforced-polymer (FRP) bars recently constructed in North America, namely Wotton, Magog, Cookshire-Eaton, Val-Alain, and Melbourne bridges in Quebec, Canada, and Morristown bridge in Vermont, USA. All six bridges are girder type, with main girders made of either steel or prestressed concrete. The main girders are supported over spans ranging from 26.2 to 50.0 m. The deck is a 200–230 mm thick concrete slab continuous over spans of 2.30–3.15 m. Different types of glass- and carbon-FRP reinforcing bars and conventional steel were used as reinforcement for the concrete deck slab. The six bridges are located on different highway categories, which means different traffic volume and environmental conditions. The bridges are well instrumented at critical locations for internal temperature and strain data collection using fibre optic sensors. These sensors are used to monitor the deck behaviour from the time of construction to several years after the completion of construction. The bridges were tested for service performance using calibrated truckloads. In parallel, a finite element analysis (FEA) was conducted and verified against the results of the field load tests. The FEA was then used to run parametric studies to investigate the effect of several important parameters such as FRP reinforcement type and ratio on the service and ultimate behaviour of these bridge decks. The analytical and field results under real service conditions, in terms of deflections, cracking, and strains in reinforcement and concrete, were comparable to those of concrete bridge deck slabs reinforced with steel.Key words: bridges deck slabs, fibre-reinforced-polymer (FRP) bars, field testing, finite element analysis.

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Lee, Hisen Hua, Yen Shuo Chen e Chi Wen Cheng. "Experimental Study on HMPE Fiber Reinforced Concrete". Advanced Materials Research 598 (novembre 2012): 336–40. http://dx.doi.org/10.4028/www.scientific.net/amr.598.336.

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Abstract. Concrete as a most popular construction material has many advantages such as easiness to be formed into various shapes, common availability and relative low cost. However, the low tensile strength and brittleness are disadvantages for wider application of the material. In this study, an advanced material of high strength and strong abrasion resistance HMPE fiber was used to reinforce concrete properties. A series of experimental testing were carried out to examine the properties of both fresh and hardened HMPE fiber reinforced concrete. It was found that the addition of an HMPE fiber material in concrete may enhance its compressive strength as high as 20% increment without water-reducing admixture. If a water-reducing admixture was applied, the increment of compressive strength may reach as high as 25% for 1.5% volume ratio of fiber contained in concrete.

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Weiler, Lia, e Anya Vollpracht. "Environmental Compatibility of Carbon Reinforced Concrete: Irrigated Construction Elements". Key Engineering Materials 809 (giugno 2019): 314–19. http://dx.doi.org/10.4028/www.scientific.net/kem.809.314.

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To foster a sustainable deployment of the innovative composite material ‘carbon concrete composite’ in the building sector, it is necessary to ensure its resource efficiency and environmental compatibility. The Institute for Building Materials Research of the RWTH Aachen University is therefore investigating the leaching behavior of this material, especially for the case of irrigated façade elements. Laboratory and outdoor exposure tests are run to determine and assess the heavy metal and trace element emissions by leaching. Feasible interconnections between laboratory and outdoor examinations can be used to develop a faster testing of future composite materials. Current results show no critical release of environmental harmful substances from carbon concrete composite.

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Ghindea, Cristian Lucian, Ionut Radu Racanel e Radu Cruciat. "Dynamic Testing of a Reinforced Concrete Road Bridge". Key Engineering Materials 601 (marzo 2014): 207–10. http://dx.doi.org/10.4028/www.scientific.net/kem.601.207.

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Considering on one hand the calculation model of the bridge, simplifying assumptions and design criteria and on the other hand the inherent differences between the project and final structure, the real structure behaviour under traffic loads can be different from that one considered in the design stage. Therefore the need of experimental tests before commissioning of bridges arises and this task is generally conditioned by complexity of the structure, the technologies used in construction and the requirements of the relevant stakeholders. The paper presents the test conditions for a reinforced concrete road bridge in Romania and the results obtained following the experimental tests. The experimentally determined dynamic characteristics of the bridge and the peek vertical accelerations are compared with those obtained by performing numerical analyses of the bridge. Due to the fact that the bridge is provided with walkways, it is appropriate to presume that the vibrations induced by road traffic will affect the pedestrians walking on the bridge. Same experimental data presented above can provide a view into how traffic induced vibrations can affect pedestrians on the bridge. For this reason, in the paper are presented the results in terms of human perception and the comparison between the resulting values and some generally accepted values

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Motter, Christopher J., David C. Fields, John D. Hooper, Ron Klemencic e John W. Wallace. "Steel-Reinforced Concrete Coupling Beams. I: Testing". Journal of Structural Engineering 143, n. 3 (marzo 2017): 04016191. http://dx.doi.org/10.1061/(asce)st.1943-541x.0001670.

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MORDOVSKY, Sergey S., Nikolay A. ILYIN, Denis A. PANFILOV, Valeriya N. TALANOVA e Yana A. BUZOVSKAYA. "METHOD OF MODELING A REINFORCED CONCRETE BEAM WITH DOUBLE REINFORCEMENT FOR STRENGTH, DEFORMATION AND FIRE RESISTANCE". Urban construction and architecture 9, n. 1 (15 marzo 2019): 4–9. http://dx.doi.org/10.17673/vestnik.2019.01.1.

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The article presents a new technical solution, which relates to the field of construction, in particular, to the testing of bending reinforced concrete elements - building beams for strength, deformation and fire resistance on a scale model. The new method of solution implies an increase in the information content, visual clarity and depth of experimental studies of reinforced concrete beams as a result of using the cost-effective way of designing geometric and forceful similarity to the scale model of reinforced concrete beams for strength, deformation and fire resistance. The proposed method allows us to estimate the limiting states of a reinforced concrete beam by strength, deformation and fire resistance; develop an analytical model for calculating the actual fire resistance; save on labor costs in the manufacture of large scale model of full scale design for its testing.

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Ivanchev, I. "Research on concrete compressive strength in existing reinforced concrete elements with Schmidt hammer, ultrasonic pulse velocity method and destructive testing of cores". IOP Conference Series: Materials Science and Engineering 1228, n. 1 (1 marzo 2022): 012034. http://dx.doi.org/10.1088/1757-899x/1228/1/012034.

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Abstract Concrete is a widely used material in construction. Quality control, maintenance and extending its service life are major issues after the construction stage and during the service of reinforced concrete buildings and facilities. This article presents the author’s experimental results for determining the compressive strength of concrete for tests on 12 reinforced concrete beams at the age of concrete 1926th day. In previous studies, some of the beams were loaded to a stage corresponding to the yield strength of the longitudinal tensile reinforcement, and others to a loading stage before yield, reaching a maximum crack width of 0.3 mm. The reinforced concrete elements were kept indoors for two years, and for the next more than three years they were left outdoors, exposed to external atmospheric influences. In the research was used combination of non-destructive and partially destructive techniques. The compressive strength of the concrete was determined using the method of elastic rebound (Schmidt hammer), ultrasonic pulse velocity method and partially destructive techniques - core sampling. The relative errors in the values of compressive strength obtained by the different methods were calculated. A comparative analysis of the experimentally obtained results by different methods was made. The tests were performed according to European standards for non-destructive and destructive testing of reinforced concrete structures.

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Pukharenko, Yuri V., Dmitry A. Panteleev e Mikhail I. Zhavoronkov. "Diagrams of Deformation of Cement Composites Reinforced with Steel Wire Fiber". Scientific journal “ACADEMIA. ARCHITECTURE AND CONSTRUCTION”, n. 2 (23 luglio 2018): 143–47. http://dx.doi.org/10.22337/2077-9038-2018-2-143-147.

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Modern construction practice acquires such a tendency, at which it is required to use materials with increased physical, mechanical and operational characteristics, and at the same time, do not require significant material, labor and energy costs for their production. One of the most promising building materials that meet the requirements is fiber-reinforced concrete. However, the increase in the volume of its use is limited by the insufficient degree of study of its properties and characteristics. This problem is aggravated by the constantly expanding range of reinforcing fibers, which can give composites produced on their basis, completely different properties and characteristics. One of the most important characteristics of fiber-reinforced concrete is crack resistance. The most informative method of research of this characteristic is the construction and analysis of deformation and fracture diagrams of samples obtained during bending tensile strength tests. At the initial stage of the described study, several series of fiber-reinforced concrete samples were tested. During the tests, a standard method for assessing the fracture toughness of heavy and fine-grained concretes, governed by the requirements of GOST 29167, was used. A device specially designed for testing fiber-reinforced concrete was used. As a result of the tests, a general view of the deformation diagrams of fiber-reinforced concrete samples was established, strength and energy characteristics of crack resistance, as well as the modulus of elasticity were found, and the labor intensity of the tests was high. In this paper we describe a possible way of obtaining fracture patterns for fiber-reinforced concrete by calculation. The resulting diagrams of deformation of fiber-reinforced concrete samples are built on several key points, the determination of which coordinates is made by calculation. The paper compares the experimental and calculated fracture toughness characteristics of fiber-reinforced concrete manufactured using steel wire fiber. Comparison of the data presented indicates a satisfactory agreement between the calculated and experimental data, which proves the validity of the proposed method for obtaining fiber-reinforced concrete deformation diagrams.

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Parsekian, G. A., N. G. Shrive, T. G. Brown, J. Kroman, P. J. Seibert, V. H. Perry, A. Boucher e G. Ghoneim. "Full-scale testing of a fibre-reinforced concrete footbridge". Proceedings of the Institution of Civil Engineers - Bridge Engineering 162, n. 4 (dicembre 2009): 157–66. http://dx.doi.org/10.1680/bren.2009.162.4.157.

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Johnson, Nathan, Richard T. Ranf, M. Saiid Saiidi, David Sanders e Marc Eberhard. "Seismic Testing of a Two-Span Reinforced Concrete Bridge". Journal of Bridge Engineering 13, n. 2 (marzo 2008): 173–82. http://dx.doi.org/10.1061/(asce)1084-0702(2008)13:2(173).

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Delatte, Norbert J., David W. Fowler e B. Frank McCullough. "Full-Scale Test of High Early Strength Bonded Concrete Overlay Design and Construction Methods". Transportation Research Record: Journal of the Transportation Research Board 1544, n. 1 (gennaio 1996): 9–16. http://dx.doi.org/10.1177/0361198196154400102.

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For rehabilitation of concrete pavements, resurfacing with a bonded concrete overlay (BCO) may provide significantly longer life and reduced maintenance costs. Two important issues are bonding and rapid reopening of resurfaced sections. The project objectives were to determine a method of constructing a BCO under extreme weather conditions in El Paso, Texas, that would ensure early opening to traffic and achieve design requirements for long-term performance, and to investigate methods of detecting and mapping delaminations nondestructively. A BCO test slab that was designed and constructed for a full-scale test of feasible design and construction alternatives is reported. The month of June was selected for the test because severe environmental conditions were expected. The experimental variables encompassed in eight test sections were reinforcement of concrete (plain, polypropylene fiber–reinforced, and steel fiber–reinforced), use of shear connectors (nails and anchors), reinforcement, surface preparation, and day or night construction. A weather station was used to record air temperature, relative humidity, and wind speed. By combining these data with concrete temperatures, evaporation rates could be calculated. Several nondestructive testing methods were used to attempt to detect and map delaminations. The results developed from the test are presented in terms of observations during construction, weather and slab temperatures, coring and pull-off testing, delamination detection, cracking, and slab loading. Recommendations are made for construction and quality control of BCOs for early opening to traffic.

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Kiss, Imre, Andrei Mihai Baciu, Ilare Bordeasu e Lavinia Madalina Micu. "Compressive Strength of Stripes and Flakes of Recycled Polyethylene Terephthalate (PET) Added Concrete". Materiale Plastice 57, n. 1 (17 aprile 2020): 244–52. http://dx.doi.org/10.37358/mp.20.1.5333.

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The wastes from polyethylene terephthalate (PET) packaging can be turned into armatures for concrete used in the transports infrastructure (roads with rigid concrete structure, pedestrian and concrete pavements and borders), as well as in the construction of safety elements (support walls, bulwark foundations). This experimental research was meant to create dispersed reinforced concrete with armatures from polyethylene waste, originated from the recycling programmes of PET-type packaging. The experimental programme was aimed at constructing some samples of dispersed reinforced concrete from recycled material coming from polyethylene terephthalate (PET) packaging wastes, their testing to the compressive strength and the comparison of results with the characteristics of the standardised samples of concrete (class C30/37). All the reinforcements used in this work to consolidate the dispersed reinforced concrete type were made from a mix of polyethylene terephthalate (PET) packages, of different types and characteristics, which are found daily in supermarkets and which then reach waste. The choice of a mix of polyethylene terephthalate (PET) packaging was chosen in order to render the general recycling of these types of materials as good as possible.

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Kirtas, E., e D. J. Kakaletsis. "Numerical Investigation of Influential Parameters Concerning the Experimental Testing of RC Frames Under Cyclic Loading". Open Construction and Building Technology Journal 7, n. 1 (30 dicembre 2013): 230–43. http://dx.doi.org/10.2174/1874836801307010230.

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Numerical simulations have been widely used to study the inelastic response of reinforced concrete structures under earthquake loading. Yet, due to the complex nature of structural inelastic behavior, experimental results are often required to verify the efficiency of applied numerical schemes. In this paper, experimental results of bare reinforced concrete frame models are employed to validate numerical calculations using the code Seismostruct. Moreover, numerical simulations investigate the influential parameters related to the physical experiment configuration and numerical analysis options and determine their effect on the obtained structural response. The experimental setup concerns a well-defined case study of a reinforced concrete frame under cyclic horizontal loading. The fixed base frame is subjected to increasing horizontal forces, leading to the development of plastic hinges at the structural elements. The adopted numerical approach describes successfully the inelastic behavior of the frame, as indicated by the obtained results of the overall structural response as well as the plastic hinge formation at cross section level. Comparison of the plastic hinge formation mechanism in particular, raises interesting remarks on the conditions and constraints of the physical experiments and highlights the valuable contribution of numerical simulations in their design.

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Wang, Tao, Xi Chen, Wen Feng Li e Qi Song Miao. "Seismic Performance of Masonry Buildings Retrofitted by Pre-Cast RC Panels". Applied Mechanics and Materials 166-169 (maggio 2012): 1811–17. http://dx.doi.org/10.4028/www.scientific.net/amm.166-169.1811.

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Proposed in this study is a retrofitting technology that can be applied on exiting masonry buildings. It employs pre-cast reinforced concrete panels to confine existing masonry structure. The pre-cast members constitute a frame which encomprises the existing building. The confinement effectively improves the ductility, strength, and stiffenss of masonry structures. Moreover, the reinforced concrete panels are fabricated in factory, significantly reduces the situ construction and construction period. To demonstrate the design theory, construction organization, and seismic performance of the retrofitted structure, a full-scale structure was tested physically. Pseudo-dynamic testing results indicate the feasibilty and effectiveness of the proposed retrofitting technology.

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Madjlessi, Noosha, Demitrios M. Cotsovos e Mojtaba Moatamedi. "Drop‐weight testing of slender reinforced concrete beams". Structural Concrete 22, n. 4 (5 maggio 2021): 2070–88. http://dx.doi.org/10.1002/suco.202000395.

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Mikerego, Emmanuel, Nestor Niyonzima e Jean Claude Ntirampeba. "Impact of impurities of local construction materials on the bearing capacity of the concrete used in structures in Burundi". Vestnik MGSU, n. 10 (ottobre 2021): 1357–62. http://dx.doi.org/10.22227/1997-0935.2021.10.1357-1362.

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Introduction. The article is about an assessment of the impact of impurities contained in the local construction materials on the mechanical characteristics of the concrete used in reinforced concrete structures in Burundi. Materials and methods. The methodology of the study consisted in varying the quantity of impurities for the manufacturing of the concrete experimental cubic samples. The grain sizes of the studied ordinary concrete were in the favourable zones according to the recommended granulometry for standard concretes. Simulation of impurities was made by adding in the mixing water solid particles taken from a local rock called “red earth”. The particles were composed by (24 %) of clays, (38 %) of silts and (38 %) of sands. As for the used cement in this study, it was the type CEM I (32.5). The quantities of impurities were expressed in grams per litre of mixing water (g/l) and were varying from (0 g/l) to (100 g/l) with a step of (20 g/l). The prepared experimental concrete samples were stored in the laboratory of materials at the University of Burundi and were subjected to compression testing under hydraulic press after 28 days. Results. The impact of impurities consisting of (24 %) of clays, (38 %) of silts and (38 %) of sands is identified. Each increase of (20 g) of impurities in a litre of mixing water induces an average decrease of (4 %) on the compressive strength and the Young’s modulus for an ordinary concrete. Conclusions. The impact of impurities contained in the local construction materials used in the manufacturing of the concrete for reinforced concrete structures in Burundi is studied. Each increase of (20 g) of impurities in a litre of mixing water induces an average decrease of (4 %) on the compressive strength and the Young’s modulus of an ordinary concrete. For Burundi, a curve for the approximation of the bearing capacity of the concrete used in reinforced concrete structures according to the quantity of impurities contained in the local construction materials was established. Hence, it is advisable to start by the specification of the quantity of impurities contained in the construction materials before making the concrete for reinforced concrete structures in order to predict the mechanical performances of the concrete used in reinforced concrete structures.

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Komárková, Tereza. "Design of Methodology for Non-Destructive Testing of Steel-Reinforced-Fiber-Concrete". Key Engineering Materials 714 (settembre 2016): 179–85. http://dx.doi.org/10.4028/www.scientific.net/kem.714.179.

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Measuring instruments used for non-destructive testing of structures thanks to advances in electronics and electrical engineering are still more frequently applied. Among the building materials with which the ability to perform quality control using non-destructive testing methods would be most welcome is indisputably steel reinforced fibre concrete (SFRC). The paper deals with the design of new methods and methodologies that enable determination of the concentration and orientation of steel fibres in steel fibre reinforced concrete. Especially the distribution of steel fibres in concrete is the quintessential aspect of this construction material. Initial results of experiments have demonstrated the applicability of the proposed methods and methodologies and the objective of the article is to introduce it to the scientific community.

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SADOVSKAYA, E., S. LEONOVICH e N. BUDREVICH. "PRACTICAL TESTING OF A MULTIPARAMETER METHOD FOR ASSESSING THE QUALITY OF FIBER CONCRETE ON A CONSTRUCTION SITE". Herald of Polotsk State University. Series F. Civil engineering. Applied sciences 31, n. 8 (29 giugno 2022): 32–37. http://dx.doi.org/10.52928/2070-1683-2022-31-8-32-37.

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This article presents the results of the practical application of a multi-parameter method for assessing the quality of fiber-reinforced concrete at a construction site. A monolithic fiber-reinforced concrete industrial floor in the production workshop is being investigated. Non-destructive testing methods are used: elastic rebound, ultrasonic pulse, ultrasonic tomography. As a result of the tests, the values of compressive strength, the thickness of the structure under study (with one-sided access), and the homogeneity of the material (voids and fiber "hedgehogs") were obtained.

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Pildysh, M., R. J. Slopek, J. O. H. Nunn e R. A. Keys. "Bearspaw Development: design and construction of a side-channel overflow spillway". Canadian Journal of Civil Engineering 17, n. 3 (1 giugno 1990): 423–30. http://dx.doi.org/10.1139/l90-046.

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Abstract (sommario):

An emergency spillway with a capacity of 1840 m3/s has been built to increase the spillway capacity of the 30-year-old Bearspaw Development so that it can safely pass the probable maximum flood. A unique aspect of the free-overflow, side-channel emergency spillway is the weir. This consists of an earthfill dyke with a cap and downstream facing of reinforced concrete. Comprehensive hydraulic model testing was undertaken to provide detailed design data and optimize the design of the emergency spillway. The overflow weir substructure is a zoned earthfill dyke with a 2 mm thick polyethylene membrane at the top of the impervious core to prevent frost heave of the concrete lining. The reinforced concrete lining of the spillway is required for erosion protection and is designed to withstand the hydrodynamic drag and uplift forces caused by flowing water as well as piezometric uplift pressures due to seepage. An extensive underdrainage system was installed to reduce uplift pressures under the lining. An unlined return channel excavated through overburden and rock conducts spill way discharges back to the river. This paper describes the model testing, design, and construction of the emergency spillway. Key words: spillway, overflow, weir, erosion, drainage, hydrodynamic, frost heave, membrane, revetment, model testing.

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Buonopane, S. G., e R. N. White. "Pseudodynamic Testing of Masonry Infilled Reinforced Concrete Frame". Journal of Structural Engineering 125, n. 6 (giugno 1999): 578–89. http://dx.doi.org/10.1061/(asce)0733-9445(1999)125:6(578).

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30

Lecieux, Yann, Emmanuel Rozière, Virginie Gaillard, Cyril Lupi, Dominique Leduc, Johann Priou, Romain Guyard, Mathilde Chevreuil e Franck Schoefs. "Monitoring of a Reinforced Concrete Wharf Using Structural Health Monitoring System and Material Testing". Journal of Marine Science and Engineering 7, n. 4 (27 marzo 2019): 84. http://dx.doi.org/10.3390/jmse7040084.

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Abstract (sommario):

This paper presents the Structural Health Monitoring (SHM) system developed for a port wharf of a freight terminal, in Saint-Nazaire, France. This concrete structure has been equipped with a multi-sensor system for the monitoring of concrete ageing. The measurement chain is designed to detect the penetration of chloride ions in order to quantify the risk of reinforcement bars corrosion. Modifications of the mechanical behavior of the structural elements of the wharf are also monitored. At first, the sensors embedded within the structure and the acquisition devices are described. The data from the monitoring performed during the first months of the structure service life are then presented. The concrete monitoring at early age providing data like temperature history, strain and resistivity is useful both for the wharf owner and the construction company since it indicates where concrete shrinkage is likely to cause cracking and gives an indicator of material hardening. These data were compared to the results of material tests carried out on concrete. The study shows that a measurement chain dedicated to the SHM could be a useful tool for validating the quality of the construction of a reinforced concrete structure before being used in the framework of long-term monitoring.

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Ali, A., Z. Soomro, S. Iqbal, N. Bhatti e A. F. Abro. "Prediction of Corner Columns’ Load Capacity Using Composite Material Analogy". Engineering, Technology & Applied Science Research 8, n. 2 (19 aprile 2018): 2745–49. http://dx.doi.org/10.48084/etasr.1879.

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Abstract (sommario):

There are numerous reasons for which concrete has become the most widely used construction material in buildings, one of them being its availability in different types, such as fiber-reinforced, lightweight, high strength, conventional and self-compacting concrete. This advantage is specially realized in high-rise building construction, where common construction practice is to use concretes of different types or strength classes in slabs and columns. Columns in such structures are generally made from concrete which is higher in compressive strength than the one used in floors or slabs. This raises issue of selection of concrete strength that should be used for estimating column capacity. Current paper tries to address this issue by testing nine (09) sandwich column specimens under axial loading. The floor concrete portion of the sandwich column was made of normal strength concrete, whereas column portions from comparatively higher strength concrete. Test results show that aspect ratio (h/b) influences the effective concrete strength of such columns. A previously adopted methodology of composite material analogy with some modifications has been found to predict well the capacity of columns where variation in floor and concrete strength is significant.

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Buller, A. H., M. Oad e B. A. Memon. "Flexural Behavior of Reinforced RAC Beams Exposed to 1000°C Fire for 18 Hours". Engineering, Technology & Applied Science Research 9, n. 3 (8 giugno 2019): 4225–29. http://dx.doi.org/10.48084/etasr.2733.

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Abstract (sommario):

In order to meet the socio-economic demands around the globe, construction industry not only consumes concrete at a very fast pace but also yields huge amounts of construction and demolishing waste. The phenomenon gives rise to environmental issues due to production of concrete ingredients and due to dumping of the waste. Therefore, one of the solutions is the production of green concrete utilizing demolished waste. This research work studies the effect of prolonged fire (18 hours) on the flexural behavior of reinforced concrete–recycled aggregate beams. The beams were using 50% replacement of natural coarse aggregates with demolished concrete. The beam samples were cast as both normal and rich mix concrete and were cured for 28 days. After curing, the beams were exposed to fire at 1000°C in a purpose made oven, followed by testing in a universal load testing machine under central point load. The test results show that the proposed beams (cast with rich mix) exhibited about 22% reduction in flexural strength. The failure mode of the beams was observed as shear failure.

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Bodnárová, Lenka, Jitka Peterková, Jiri Zach e Iveta Nováková. "Study of Heat Transport in Structure of Concrete". Advanced Materials Research 1000 (agosto 2014): 302–5. http://dx.doi.org/10.4028/www.scientific.net/amr.1000.302.

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Abstract (sommario):

Current trend of construction of ring roads in large cities going often underground emphasizes safety of implementation and using of such constructions, which is closely connected to possible risks of a fire in these predominantly monolithic structures made from steel reinforced concrete. The paper gives results of the research focused on thermally-technical properties of cement based composite materials resistant to high temperature suitable for application in places with higher risk of fire, like secondary lining of tunnels or underground car parks. The aim was verification of appropriateness of testing mix-designs for application in structures possibly endangered by fire.

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Ning, Chao-Lie, Wenqi Du e Bing Li. "Biaxial hysteretic model for the characterization of quasi-static testing of shear-critical reinforced concrete columns". Advances in Structural Engineering 22, n. 2 (17 luglio 2018): 349–63. http://dx.doi.org/10.1177/1369433218788369.

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Abstract (sommario):

Given that the biaxial hysteretic model of shear-critical reinforced concrete columns is usually developed by incorporating with the single-degree-of-freedom system to write its expression in differential equation of motion control, it is unfeasible to match with the experimental data of the biaxial quasi-static testing in terms of force-displacement relationship. Therefore, a simple and effective biaxial hysteretic model is proposed in this study based on the Bouc–Wen–Baber–Noori model for characterizing the biaxial quasi-static testing of shear-critical reinforced concrete columns. An incremental numerical algorithm is then proposed to solve the pair of coupled differential equations based on the backward Euler discretization method and Newton–Raphson iteration scheme. Moreover, the influence of critical model parameters affecting the typical hysteretic characteristics of shear-critical reinforced concrete columns, such as strength deterioration, stiffness degradation, pinching phenomena, and biaxial coupling effect, is investigated, respectively, to demonstrate the capability of the biaxial hysteretic model developed. Finally, a parameter calibration procedure using the differential evolution algorithm is introduced to calibrate the magnitude of involved model parameters by comparing with the experimental data of the biaxial quasi-static testing. According to the investigation, it is found that the developed biaxial hysteretic model can reasonably describe the typical hysteretic characteristics of shear-critical reinforced concrete columns under biaxial quasi-static excitation. Following the proposed parameter calibration procedure, the biaxial hysteretic model developed produces the biaxial hysteretic loops of shear-critical reinforced concrete columns, which is in good agreement with the experimental data once the magnitude of involved model parameters is calibrated.

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Lumingkewas, Riana Herlina, Akhmad Herman Yuwono, Sigit Pranowo Hadiwardoyo e Dani Saparudin. "The Compressive Strength of Coconut Fibers Reinforced Nano Concrete Composite". Materials Science Forum 943 (gennaio 2019): 105–10. http://dx.doi.org/10.4028/www.scientific.net/msf.943.105.

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Abstract (sommario):

The compressive strength of the concrete reviewed in this study uses nanosilica and coconut fibers. The addition of coconut fibers to concrete contributes to the construction of sustainable and environmentally friendly building materials. The testing method carried out physically and mechanically. Testing the compressive strength of the nanoconcrete composite with variations in the amount of nanosilica which substituted with cement. Using variations of nanosilica composition, namely 0%, 0.5%, 1%, 1.5%, and 2% added with coconut fiber to determine the effect of compressive strength from nanoconcrete composite. The results obtained are the optimal value of concrete compressive strength with nanosilica is the addition of 2% nanosilica, which increases 43% of standard concrete. Moreover, on concrete with the addition of nanosilica and the addition of coconut fibers 1% test results in concrete compressive strength which is optimal in the addition of 0.5% nanosilica, which is 58% increase from normal concrete. The conclusion of this study that the addition of nanosilica and reinforced with coconut fiber will increase the compressive strength of concrete, this is an excellent composite material to get environmentally friendly building materials using.

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Shu, Jiangpeng, Niklas Bagge e Jonny Nilimaa. "Field Destructive Testing of a Reinforced Concrete Bridge Deck Slab". Journal of Bridge Engineering 25, n. 9 (settembre 2020): 04020067. http://dx.doi.org/10.1061/(asce)be.1943-5592.0001604.

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37

Zezulová, Eva, e Tereza Komárková. "Techniques of Non-Destructive Testing of Steel Fiber Reinforced Concrete". Key Engineering Materials 755 (settembre 2017): 153–58. http://dx.doi.org/10.4028/www.scientific.net/kem.755.153.

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Abstract (sommario):

Non-destructive testing (NDT) is seeing increasingly frequent use in civil engineering thanks to the fact that the tests are repeatable and do not cause serious damage to the material. The requirements for the development and modernization of available testing devices and methodologies are ever increasing and the testing of existing structures often requires the use of NDT. Unfortunately, every measurement and methodology has its limits and the measurement devices for the evaluation of steel fiber reinforced concrete (SFRC) are no exception. In recent decades there has been an effort to modernize and develop existing measurement devices for SFRC testing. This building material is commonly used especially in large-scale structures. Nevertheless, the technology of SFRC could seem complicated when compared with ordinary concrete and the very nature of this composite material could lead to SFRC inhomogeneity during construction. This paper describes the assessment of SFRC by more or less available methodologies and measurements utilizing non-destructive principles.

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Xu, Juechun, Chengqing Wu, Jun Li e Jintao Cui. "Simplified finite element method analysis of ultra-high-performance fibre-reinforced concrete columns under blast loads". Advances in Structural Engineering 20, n. 1 (28 luglio 2016): 139–51. http://dx.doi.org/10.1177/1369433216646012.

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Abstract (sommario):

Ultra-high-performance fibre-reinforced concrete has exceptional mechanical properties including high compressive and tensile strength as well as high fracture energy. It has been proved to be much higher blast resistant than normal concrete. In this article, flexural behaviours of ultra-high-performance fibre-reinforced concrete columns were investigated through full-scale tests. Two 200 mm × 200 mm × 2500 mm columns with and without axial loading were investigated under three-point bending tests, and their load–displacement relationships were recorded and the moment curvatures were derived. The derived moment curvature relationships of ultra-high-performance fibre-reinforced concrete columns were then incorporated into a computationally efficient one-dimensional finite element model, which utilized Timoshenko beam theory, to determine flexural response of ultra-high-performance fibre-reinforced concrete columns under blast loading. After that, the one-dimensional finite element model was validated with the real blast testing data. The results show good correlation between the advanced finite element model and experimental results. The feasibility of utilizing the one-dimensional finite element model for simulating both high-strength reinforced concrete and ultra-high-performance fibre-reinforced concrete columns against blast loading conditions is confirmed.

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39

Muir, C. A., D. K. Bull e S. Pampanin. "Preliminary observations from biaxial testing of a two-storey, two-by-one bay, reinforced concrete slotted beam superassembly". Bulletin of the New Zealand Society for Earthquake Engineering 45, n. 3 (30 settembre 2012): 97–104. http://dx.doi.org/10.5459/bnzsee.45.3.97-104.

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Abstract (sommario):

Displacement incompatibility between reinforced concrete moment frames and precast flooring systems has been shown experimentally, and in historical earthquakes, to be an area of concern. Plastic hinge formation necessitates beam damage and the resulting elongation of the beam reduces the seating length of the floor, exacerbates the floor damage and induces unanticipated force distributions in the system. In severe cases this can lead to collapse. The slotted beam is a detail that protects the integrity of the floor diaphragm, respects the hierarchy of strengths intended by the designer and sustains less damage. The detail provides the same ductility and moment resistance as traditional details, whilst exhibiting improved structural performance. This is achieved with only a subtle change in the detailing and no increase in build cost. This paper briefly presents the development of the slotted beam in reinforced concrete. The design and construction of a large scale reinforced concrete slotted beam superassembly is described. The experimental method used to undertake biaxial quasi-static testing is introduced. Preliminary observations from the experiment are presented. It is shown that the reinforced concrete slotted beam is a viable replacement for the traditional monolithic detail. Extremely promising structural performance and significantly reduced damage compared to monolithic reinforced concrete details is presented.

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Konrád, Petr, e Radoslav Sovják. "Experimental procedure for determination of the energy dissipation capacity of ultra-high-performance fibre-reinforced concrete under localized impact loading". International Journal of Protective Structures 10, n. 2 (13 marzo 2019): 251–65. http://dx.doi.org/10.1177/2041419618819506.

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Abstract (sommario):

Research presented in this article is aimed to investigate the ability of ultra-high-performance fibre-reinforced concrete to absorb and dissipate mechanical energy at elevated strain rate loading. Specimens made of ultra-high-performance fibre-reinforced concrete were subjected to the low-velocity impact using the new testing procedure where no fixed supports that hold the sample during the impact were applied. The fibre volume fraction of the ultra-high-performance fibre-reinforced concrete was set as the main test variable in the framework of this study and the volumetric fraction of fibres was ranging from 0.125% to 2%. A high-speed camera was used to measure velocities of the impactor and the ultra-high-performance fibre-reinforced concrete specimen before and after the impact. Consequently, the energy dissipated by the ultra-high-performance fibre-reinforced concrete specimen during the impact was calculated using a simple energy balance equation. To determine the basic material properties of ultra-high-performance fibre-reinforced concrete, quasi-static loading rate was applied and conventional methods were used. A significant difference between the values of dissipated energies for different loading rates and various fibre volumetric fractions was observed. It can be noted that the new procedure shows a reasonable approach for testing the fibre-reinforced cementitious composites under localized impact loading and is worthy of further optimization.

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Wu, Chengqing, Liang Huang e Deric John Oehlers. "Blast Testing of Aluminum Foam–Protected Reinforced Concrete Slabs". Journal of Performance of Constructed Facilities 25, n. 5 (ottobre 2011): 464–74. http://dx.doi.org/10.1061/(asce)cf.1943-5509.0000163.

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42

Rahman, Hamid, Ted Donchev e Diana Petkova. "Modelling the behaviour of concrete shear walls with BFRP reinforcement". MATEC Web of Conferences 289 (2019): 09002. http://dx.doi.org/10.1051/matecconf/201928909002.

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Abstract (sommario):

Corrosion of steel reinforcement in concrete structures is one of the main challenges for the construction industry. FRP reinforcement could be used as alternative to steel reinforcement providing several advantages, such as high resistance to corrosion, high tensile strength and opportunity for developing a more ductile mode of destruction. The last characteristic is extremely beneficial in the aspect of lateral load resisting systems including RC shear walls. The presented modelling results consist of preparing finite element models of reinforced concrete shear walls utilizing Ansys 19.2 - Solid65 element which is capable of both cracking and crushing. The results were verified with experimental medium-scale concrete shear walls reinforced with steel and BFRP bars. The models were loaded under cyclic lateral loading following a modified ATC (Applied Technology Council guidelines for seismic testing) 24 protocol. BFRP reinforced models developed similar ultimate capacity and significantly higher energy dissipation in comparison with steel reinforced models. The promising results could provide a momentum toward construction of shear walls using FRP reinforcement with the aims of improving durability and energy dissipation.

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Türker, Temel, e Alemdar Bayraktar. "Vibration based modal testing of a scaled reinforced concrete building for construction stages". Bulletin of Earthquake Engineering 15, n. 8 (11 dicembre 2015): 3399–416. http://dx.doi.org/10.1007/s10518-015-9852-9.

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Saadoon Al-Yassri, Labeeb, Alaa Mahdi Al-Khekany e Hajer Satea Abbas. "Experimental Study of Replacement the Tension Reinforcing Bars in Concrete Beams by Steel Pipes". International Journal of Engineering & Technology 7, n. 4.20 (28 novembre 2018): 229. http://dx.doi.org/10.14419/ijet.v7i4.20.25931.

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Abstract (sommario):

Structures designed with reinforced concrete beams are used extensively in construction projects because of their functional and economic features. In this research, tested concrete beams were cast and reinforced with small diameter steel pipes and /or steel bars as flexural reinforcement to study the effect of this configuration of reinforcement on the structural behavior of reinforced concrete beams. The idea of this research involves performing and testing of four reinforced concrete beams reinforced by small diameter steel pipes with different percentages of replacement with traditional steel bars (0%, 33%, 66% and 100%). The experimental results showed that using of steel pipes reduces the flexural capacity by (2.7, 18.3, 37.5%) if compared with traditional steel bar according to the replacement percentages of (33%, 66%, and 100%) respectively. Moreover, the stiffness of beams reinforced with steel pipes (fully or partially) decreased as a result of the difference in the mechanical properties between steel bar and the steel pipe and also, the bond strength reduction between the smooth steel pipe and surrounded concrete.

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Skazlić, Marijan, e Dubravka Bjegović. "Toughness testing of ultra high performance fibre reinforced concrete". Materials and Structures 42, n. 8 (22 ottobre 2008): 1025–38. http://dx.doi.org/10.1617/s11527-008-9441-3.

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46

Wu, Chengqing, Deric John Oehlers, John Wachl, Craig Glynn, Adrian Spencer, Matthew Merrigan e Ian Day. "Blast Testing of RC Slabs Retrofitted with NSM CFRP Plates". Advances in Structural Engineering 10, n. 4 (agosto 2007): 397–414. http://dx.doi.org/10.1260/136943307783239372.

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Abstract (sommario):

In this paper, blast testing was performed on two reinforced concrete specimens: a plain reinforced concrete (RC) specimen; and an identical RC specimen retrofitted with near surface mounted (NSM) carbon fibre reinforced polymer (CFRP) plates. Each specimen was subjected to two separate explosive loads at a standoff distance of 0.6m, with the aim of investigating the performances of both specimens within both their elastic and plastic response ranges. The first blast (Blast 1) and second blast (Blast 2) consisted of an equivalent TNT charge weight of 0.079kg and 2.09kg respectively. The elastic-range responses of both specimens after the small shot (Blast 1), such as acceleration and deflection were obtained and comparisons were made between the specimens. The plastic performances of both specimens, such as tension face scabbing, crack patterns, plastic hinges and permanent deflection, after the large shot (Blast 2) were also analysed and compared. A number of unique failures and behaviours of both specimens were observed, investigated and analyzed. The test results provide a vital direction in the development of an optimal retrofit in future research.

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Lehmann, Marek, e Wiesława Głodkowska. "Shear Capacity and Behaviour of Bending Reinforced Concrete Beams Made of Steel Fibre-Reinforced Waste Sand Concrete". Materials 14, n. 11 (1 giugno 2021): 2996. http://dx.doi.org/10.3390/ma14112996.

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Abstract (sommario):

Inthis paper, we report the results of our research on reinforced concrete beams made of fine aggregate fibre composite, with the addition of steel fibres at 1.2% of the composite volume. The fine aggregate fibre composite is a novel construction material, in which the aggregate used is a post-production waste. Twenty reinforced concrete beams with varying degree of shear reinforcement, in the form of stirrups with and without the addition of steel fibres, tested under loading. The shear capacity results of reinforced concrete beams made of the fine aggregate fibre composite being bent by a transversal force, as well as the cracking forces causing the appearance of the first diagonal crack, are discussed. The stages of functioning of such elements are described. Furthermore, the effect of the steel fibres on the reduction of diagonal cracking is analysed. Computation of the shear capacity of the tested elements is performed, based on the Model Code 2010 and RILEM TC-162 TDF standards, for two variants of the compression strut inclination angle θ that measured during testing, and the minimum(in accordance with the Model Code 2010 standard). We found that the SMCFT method part of Model Code 2010 showed the best compatibility with the experimental results. The tests and analyses performed demonstrate that the developed novel fibrecomposite—the properties of which are close to, or better than, those of the ordinary concrete—can be used successfully for the manufacturing of construction elements in the shear capacity aspect. The developed fine aggregate fibrecomposite could serve, in some applications, as an alternative to ordinary concrete.

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Hou, Hetao, Weiqi Fu, Canxing Qiu, Jirun Cheng, Zhe Qu, Wencan Zhu e Tianxiang Ma. "Effect of axial compression ratio on concrete-filled steel tube composite shear wall". Advances in Structural Engineering 22, n. 3 (28 agosto 2018): 656–69. http://dx.doi.org/10.1177/1369433218796407.

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Abstract (sommario):

This study proposes a new type of shear wall, namely, the concrete-filled steel tube composite shear wall, for high performance seismic force resisting structures. In order to study the seismic behavior of concrete-filled steel tube composite shear wall, cyclic loading tests were conducted on three full-scale specimens. One conventional reinforced concrete shear wall was included in the testing program for comparison purpose. Regarding the seismic performance of the shear walls, the failure mode, deformation capacity, bearing capacity, ductility, hysteretic characteristics, and energy dissipation are key parameters in the analysis procedure. The testing results indicated that the bearing capacity, the ductility, and the energy dissipation of the concrete-filled steel tube composite shear walls are greater than that of conventional reinforced concrete shear walls. In addition, the influence of axial compression ratio on the seismic behavior of concrete-filled steel tube composite shear wall is also investigated. It was found that higher axial compression ratio leads to an increase in the bearing capacity of concrete-filled steel tube composite shear walls while a reduction in the ductility capacity.

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Lu, Jin Ping. "Testing and Specification of Polymer Concrete Materials in Singapore". Advanced Materials Research 1129 (novembre 2015): 177–84. http://dx.doi.org/10.4028/www.scientific.net/amr.1129.177.

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Abstract (sommario):

Pure cement mortar and concrete possess disadvantages such as brittleness, low bonding or adhesion strength, low tensile strength, large drying shrinkage, low chemical resistance. In order to overcome these disadvantages, polymer concrete is used as a construction material in Singapore as the properties of polymer-modified (or polymer cement) mortar and concrete are superior to conventional cement mortar. In Singapore, new products or technologies can be found through distributers, agents, etc. Singapore is able to afford and try high quality products to maintain the quality of a building and structure. The importance of applying polymer to protect, repair, coat and strengthen concrete structures in Singapore have grown in the last two decades. To ensure and maintain the standards of construction and building quality, polymer concrete are used extensively in new developments in Singapore. In this paper, the mechanical properties and its corresponding testing methods for several types of polymer concrete used in Singapore are discussed. These products include mortar used to repair concrete spalling, acrylic polymer cementitious coating, waterproofing membrane, epoxy mortars and grouts, fibre reinforced plastic (FRP) and epoxy resin. In addition, the specifications for the above products used in Singapore’s Housing Development Board (HDB) are discussed in the paper as it’s a requirement for suppliers to test their products in accredited laboratories before it can be used.

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Elbasha, Nuri Mohamed. "Reinforced HSC Beams". Key Engineering Materials 629-630 (ottobre 2014): 544–50. http://dx.doi.org/10.4028/www.scientific.net/kem.629-630.544.

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Abstract (sommario):

The primary long and short term advantages of high strength concrete are, low creep and shrinkage, higher stiffness, higher elastic modulus, higher tensile strength, higher durability (resistance to chemical attacks) and higher shear resistance. In addition, high strength concrete reduces the size of the member, which in turn reduces the form size, concrete volume, construction time, labor costs and dead load. Reducing the dead load reduces the number and size of the beams, columns and foundations. Thus there is a positive impact on reduction of maintenance and repair costs and an increase in rentable space. Other, yet to be discovered advantages may also exist. High strength concrete has definite advantages over normal strength concrete. The ductility of over reinforced HSC beams is enhanced through the application of helical reinforcement located in the compression region. The pitch of helix is an important parameter controlling the level of strength and ductility enhancement. This paper presents an experimental investigation of the effect of helices on the behavior of over reinforced high strength concrete beams through testing ten helically confined full scale beams. The helix pitches were 25, 50, 75, 100 and 160 mm. Beams’ cross section was 200×300 mm, and with a length of 4 m and a clear span of 3.6 m subjected to four point loading. The main results indicate that helix effectiveness is negligible when the helical pitch is 160 mm (helix diameter). The experimental program in this study proved that the HSC, HSS and helical confinement construct a reinforced concrete beam. This beam has the ability to resist weathering action and chemical attack while maintaining its desired engineering properties. In near future Reinforced High Strength Concrete Beam with Helical Confinement will be considered as a durable and sustainable Reinforced Concrete Beam.

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