Artículos de revistas: "Precast reinforced concrete structures"

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Nakata, Shinsuke. "Present Situation of Precast Reinforced Concrete Structures". Concrete Journal 32, n.º 5 (1994): 5–12. http://dx.doi.org/10.3151/coj1975.32.5_5.

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BOB, Corneliu, Andras LEIDAL y Liana BOB. "Reinforced Concrete Precast Structures with Rigid Connections". IABSE Congress Report 17, n.º 7 (1 de enero de 2008): 380–81. http://dx.doi.org/10.2749/222137908796293073.

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3

Tho, Vu Dinh, Elena Anatolyevna Korol, Nikolai Ivanovich Vatin y Hoang Minh Duc. "The Stress–Strain State of Three-Layer Precast Flexural Concrete Enclosure Structures with the Contact Interlayers". Buildings 11, n.º 3 (1 de marzo de 2021): 88. http://dx.doi.org/10.3390/buildings11030088.

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The research object was three-layer reinforced precast concrete enclosure structures. The structures consist of heavy concrete B25 in the external layers and polystyrene concrete B1 in the internal layer. The stress–strain state of precast concrete structures during crack formation was studied by considering the influence of contact interlayers between different types of concretes. Stereoscopic microscopy and scanning electron microscopy were used in the experimental study of multilayer concrete blocks. Samples were made with a varied break time from 30 min to two hours between the previous and the next concrete layer placings. The experimental results showed that the contact interlayer with mutual penetration of aggregates into the adjacent concrete layers is formed in the successive layer-by-layer placing of various concretes. The thickness of the contact interlayer was up to 1 cm. The contact interlayer affects the solidity of the concrete layers’ connection and the structure’s stress–strain state. A model and method for calculating cracking in three-layer reinforced concrete structures with contact interlayers based on analytical and numerical calculations are proposed. Experimental data confirm the proposed calculation method. The results of three-layer reinforced concrete beams calculations show that: (i) the difference of the moment during crack formation in three-layer reinforced concrete beams schemes with and without taking into account the contact interlayer can reach 9.9%; (ii) the moment during crack formation obtained according to the proposed method is greater than that obtained according to the scheme of the cross-section conversion from 7.4% to 9.1%.

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Jagtap, Siddhant Millind, Shailesh Kalidas Rathod, Rohit Umesh Jadhav, Prathamesh Nitin Patil, Atharva Shashikant Patil, Ashwini M. Kadam y P. G. Chavan. "Fibre Mesh in Reinforced Slabs". International Journal for Research in Applied Science and Engineering Technology 10, n.º 5 (31 de mayo de 2022): 3539–40. http://dx.doi.org/10.22214/ijraset.2022.42986.

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Abstract: Fiber Reinforced Concrete is gaining attention as an effective way to improve the performance of concrete. Fibers are currently being specified in tunneling, bridge decks, pavements, loading docks, thin unbonded overlays, concrete pads, and concretes slabs. These applications of fiber reinforced concrete are becoming increasingly popular and are exhibiting excellent performance The usefulness of fiber reinforced concrete in various civil engineering applications is indisputable. Fiber reinforced concrete has so far been successfully used in slabs on grade, architectural panels, precast products, offshore structures, structures in seismic regions, thin and thick repairs, crash barriers, footings, hydraulic structures and many other applications. This study presents understanding srength of fibre reinforced conceret. Mechanical properties and durability of fiber reinforced concrete.

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5

Polák, Aleš. "Experimental Verification of Demountable Precast Column System". Applied Mechanics and Materials 827 (febrero de 2016): 259–62. http://dx.doi.org/10.4028/www.scientific.net/amm.827.259.

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Relocation of existing concrete structures requires full or partial demolition, which consumes a lot of energy and thus has a negative impact on the environment. From environmental point of view, demountable precast structures are sustainable. They allow “recycling” to the level of precast elements and so they save significant amounts of energy and materials. Another advantage of these structures is quick assembly without wet processes. A characteristic component of precast reinforced concrete construction system for multi-storey buildings are demountable joints of load-bearing precast reinforced concrete elements. This paper is focused on experimental verification of demountable precast column structure and its demountable steel joints. The experimental research was carried out within TA02010837 “Multipurpose dismantleable prefabricated reinforced concrete building system with controlled joint properties and possibility of repeated use”.

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6

Joo, Sanghoon. "Structural Performance of Precast Concrete Arch with Reinforced Joint". Journal of the Korean Society of Civil Engineers 34, n.º 1 (2014): 29. http://dx.doi.org/10.12652/ksce.2014.34.1.0029.

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7

Liu, Hongtao, Qiushi Yan y Xiuli Du. "Seismic performance comparison between precast beam joints and cast-in-place beam joints". Advances in Structural Engineering 20, n.º 9 (20 de octubre de 2016): 1299–314. http://dx.doi.org/10.1177/1369433216674952.

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Precast reinforced concrete structures are widely used due to many constructional advantages such as faster construction speed, lower construction cost, being environmentally friendly, higher strength, and so on. To study the seismic performance of precast reinforced concrete structures, tests on beam-to-column joints of precast reinforced concrete structures were conducted under low reversed cyclic loading. In total, four joint specimens were produced in this study, including two precast joints and two cast-in-place joints. In addition to the comparison between different types of joints, the axial compression ratio of column was adopted as the main variable in this study. Analysis was carried out on the basis of the observed joint failure mode and relationships derived from the test data such as hysteresis curves, skeleton curves, stiffness degradation curves, energy dissipation capacities, and sleeve joint strain curves. Despite the closeness of energy dissipation capacity between the precast joints and the cast-in-place joints, they had different failure modes. Precast joints feature a relatively concentrated crack distribution in which the limited number of cracks was distributed throughout the plastic zone of the beam. Cast-in-place joints feature more evenly distributed cracks in the plastic zone, especially at the later stage of the loading. The steel slippage of the precast concrete joints was found influenced by the axial compression ratio. Through this study, it is concluded that seismic resistance capacity of precast concrete joint needs to be considered in design and construction and the grouting sleeve splice could be kept away from the hinge zones when precast concrete structures were used in regions of high seismicity. The results in this study can provide a theoretical basis for seismic design of precast reinforced concrete structures, which in turn can promote the application of precast reinforced concrete structures.

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8

Zhao, Dong Qi, Yi Jun Tang, Hui Li, Gui Feng Song y Feng Ling Guan. "The Application Research of Reinforced Concrete Multi-Ribbed Hollow Composite Slab in the Road Slab Culvert". Advanced Materials Research 368-373 (octubre de 2011): 307–11. http://dx.doi.org/10.4028/www.scientific.net/amr.368-373.307.

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Reinforced concrete cover in the road culvert cover design, in order to facilitate the construction, usually using precast reinforced concrete solid slab, but the overall cost is not low. This article researched a reinforced concrete multi-ribbed hollow composite slab, it based on the theory of reinforced concrete multi-ribbed slab structures, using a precast reinforced concrete ribbed slab as the bottom die, then poured reinforced concrete beams and panels rib ,and them constituted a whole stack of reinforced concrete ribbed hollow slab. This kind of cover, compared with the precast reinforced concrete solid cover, is not only good mechanical properties, high integrity, but also saving concrete, steel, and bottom slab appeared smooth and fine, lower construction cost.

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May, Sebastian, Oliver Steinbock, Harald Michler y Manfred Curbach. "Precast Slab Structures Made of Carbon Reinforced Concrete". Structures 18 (abril de 2019): 20–27. http://dx.doi.org/10.1016/j.istruc.2018.11.005.

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Folic, Radomir, Damir Zenunovic y Nesib Residbegovic. "Strength of connections in precast concrete structures". Facta universitatis - series: Architecture and Civil Engineering 9, n.º 2 (2011): 241–59. http://dx.doi.org/10.2298/fuace1102241f.

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The available experimental and numerical results of many studies of behavior of reinforced concrete connections for different stages of loading, up to fracture loading, are presented and analyzed in this paper. The problem of beam-column connection (or plate-wall connection) in prefabricated monolithic structures is emphasized. Fracture mechanisms of RC structures, the theoretical basis for their analysis, and the use of fracture mechanics in RC structures were also considered, as well as the mathematical models of prefabricated connections. In order to formulate an adequate mathematical model for calculating the connections, the dominant parameters influencing the behaviour of these connections were analyzed. A failure model for the prefabricated wall - monolithic RC plate connection was formulated. In building the model, the results of implemented experimental and numerical research of prefabricated connection in the MMS system from 2007 were used. Experiences with the implementation of the aforementioned construction system in structures in Tuzla, in the 1980's last century, were additionally used. The proposed mathematical models provide a sufficiently accurate failure assessment of prefabricated reinforced concrete connections.

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11

Feng, De‐Cheng, Zhun Wang y Gang Wu. "Progressive collapse performance analysis of precast reinforced concrete structures". Structural Design of Tall and Special Buildings 28, n.º 5 (17 de enero de 2019): e1588. http://dx.doi.org/10.1002/tal.1588.

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12

Lathamaheswari, R., R. BalaKeerthana, K. Nandhini, B. Parkavi y A. Nivedha. "Study on GFRP Reinforced Beams under Flexure". International Journal of Emerging Research in Management and Technology 6, n.º 7 (29 de junio de 2018): 156. http://dx.doi.org/10.23956/ijermt.v6i7.205.

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Acute shortage of raw materials and deterioration of reinforced concrete structural elements lead to implementation of new substitute materials and innovative technologies. Reinforced Cement Concrete structures are usually reinforced with steel bars which are subjected to corrosion at critical temperature and atmospheric conditions. The structures can also be reinforced with other materials like Fibre Reinforced Polymers (FRP). In this line Fibre Reinforced Polymer based reinforcement replacing conventional steel rod for a precast element of a prefabricated structure is considered. The precast member cast out of M25 grade concrete reinforced exclusively with locally produced Glass Fibre Reinforced Polymer (GFRP) bars including GFRP stirrups is designed, cast. Flexural behaviour of rectangular concrete beams reinforced with FRP bars and stirrups is examined with two specimens one with conventional sand as fine aggregate and another with quarry dust as fine aggregate. The load at cracking and ultimate, type of failure and crack patterns are observed and compared with those of conventional cement concrete.

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13

Kudzys, Algirdas, Romualdas Kliukas y Antanas Kudzys. "ON DESIGN FEATURES OF PROPPED AND UNPROPPED HYPERSTATIC STRUCTURES". JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 13, n.º 2 (30 de junio de 2007): 123–29. http://dx.doi.org/10.3846/13923730.2007.9636428.

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An effect of structural and technological features on the design methodology of hyperstatic precast reinforced concrete and composite steel‐concrete structures is discussed. Permanent and variable service, snow and wind loads of buildings and their extreme values are analysed. Two loading cases of precast reinforced concrete and composite steel‐concrete continuous and sway frame beams as propped and unpropped members are considered. A redistribution of bending moments for the ultimate limit state of beams is investigated. A limit state verification of hyperstatic beams by the partial factor and probability‐based methods is presented. It is recommended to calculate a long‐term survival probability of beams by the analytical method of transformed conditional probabilities.

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Noorsuhada, Md Noor, Ibrahim Azmi, Muhamad Bunnori Norazura, Mohd Saman Hamidah, Mat Saliah Soffian Noor y Shahidan Shahiron. "Fatigue Crack Inspection and Acoustic Emission Characteristics of Precast RC Beam under Repetition Loading". Applied Mechanics and Materials 773-774 (julio de 2015): 1022–26. http://dx.doi.org/10.4028/www.scientific.net/amm.773-774.1022.

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Fatigue crack of the precast reinforced concrete beam under repetition loading is vital to be examined. Reinforced concrete structures exposed to excessive repetition loading could lead to the failure of the structures. In order to examine the active fatigue crack, the reinforced concrete beams were subjected to three-point repetition maximum loading. Eight phases of maximum fatigue loading with sinusoidal wave, frequency of 1 Hz and 5000 cycles for each phase were performed on the reinforced concrete beams. The inspection was carried out with visual observation of the crack pattern and acoustic emission technique for each load phase. The signal strength of acoustic emission was investigated. It is found that the signal strength of acoustic emission and crack pattern of the reinforced concrete beam subjected to repetition loadings showed promising results for structural health monitoring.

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15

Pang, Rui, Yibo Zhang, Longji Dang, Lanbo Zhang y Shuting Liang. "Experimental and numerical investigation on the vertical bearing behavior of discrete connected new-type precast reinforced concrete floor system". Advances in Structural Engineering 23, n.º 11 (13 de marzo de 2020): 2276–91. http://dx.doi.org/10.1177/1369433220911141.

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This article proposes a new type of discrete connected precast reinforced concrete diaphragm floor system that consists of precast flat slabs and slab joint connectors. An experimental investigation of discrete connected new-type precast reinforced concrete diaphragm under a vertical distributed static load was conducted, and the effect of slab joint connectors on the load-bearing capacity was evaluated. Then, a finite element analysis of discrete connected new-type precast reinforced concrete diaphragm, precast reinforced concrete floors without slab connectors, and cast-in-situ reinforced concrete floor were performed to understand their working mechanism and determine the differences in load-bearing behavior. The results indicate that the load-bearing capacity and stiffness of discrete connected new-type precast reinforced concrete diaphragm increase considerably as the hairpin and cover plate hybrid slab joint connectors can efficiently connect adjacent precast slabs and enable them to work together under a vertical load by transmitting the shear and moment forces in the orthogonal slab laying direction. The deflection of discrete connected new-type precast reinforced concrete diaphragm in orthogonal slab laying direction is mainly caused by the opening deformation of the slab joint and the rotational deformation of the precast slabs. This flexural deformation feature can provide reference for establishing the bending stiffness analytical model of discrete connected new-type precast reinforced concrete diaphragm in orthogonal slab laying direction, which is vitally important for foundation of the vertical bearing capacity and deformation calculation method. The deflection and crack distribution patterns infer that the discrete connected new-type precast reinforced concrete diaphragm processes the deformation characteristic of two-way slab floor, which can provide a basis for the theoretical analysis of discrete connected new-type precast reinforced concrete diaphragm.

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16

Bogdan, Hauşi Sorin. "Issues Regarding the Appropriateness of Using Precast Reinforced Concrete Frame Structures Compared to Monolithic Reinforced Concrete Frame Structures, in Office Buildings and Residential Buildings". Bulletin of the Polytechnic Institute of Iași. Construction. Architecture Section 67, n.º 3 (18 de julio de 2022): 35–50. http://dx.doi.org/10.2478/bipca-2021-0023.

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Abstract Given the current context at national and European level in terms of reducing skilled labour force in constructions, as well as the high level of density and traffic in large cities, there is an increasing emphasis on the possibility of shortening the duration of building the structural frames on site, reducing the number of workers or even reducing the level of noise pollution. Thus, the introduction of precast technologies in the case of office buildings and residential buildings, with multi-storey frame structure, is becoming an increasingly pressing and topical issue. The purpose of this paper is to enable structural engineers, architects and potential investors to consciously choose the type of optimal structure, taking into account a number of technical and economic aspects. In this sense, in order to highlight the main advantages and disadvantages of using multi-storey precast reinforced concrete frame structures, a comparative case study will be carried out between a precast frame structure and a monolithic frame structure, respectively.

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17

Shi, Xiaona, Xian Rong, Lin Nan, Lida Wang y Jianxin Zhang. "A New Steel-Joint Precast Concrete Frame Structure: The Design, Key Construction Techniques, and Building Energy Efficiency". Buildings 12, n.º 11 (14 de noviembre de 2022): 1974. http://dx.doi.org/10.3390/buildings12111974.

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Assembled methods play a critical role in the construction of precast concrete structures. However, conventional dry-connections-like sleeve grouting joints in precast concrete structures lagged at a low construction and management efficiency with poor quality control. In this study, a novel steel joint for precast reinforced concrete beam-column components is proposed to improve constructability. New joints transform the assembled method from reinforced concrete members into a steel structure by setting a pre-embedded steel connector at both ends of reinforced concrete beams and columns, showing outstanding economic, durability, and fire resistance capabilities. The construction process, construction efficiency, economy, and energy consumption were discussed based on the material, structure, and construction hybrid characteristics. Numerical simulation and structural health monitoring methods are used to monitor and evaluate the deformation and stress state of the proposed system in the whole construction process, so as to optimize the construction scheme and ensure safe and orderly construction. The results reveal that the FEA-simulated values of key building components during construction are in good agreement with the actual monitoring values, which verifies the feasibility of the FEM models and provides a guarantee for construction safety; the construction period of the proposed assemble system is reduced by approximately 56% and 40%, compared with the conventional reinforced concrete frame structure and cast-in-place joints in the precast concrete frame structure, respectively. Meanwhile, the energy consumption of buildings decreases by 20%. This research provides a theoretical basis for the design, calculation, and application of assembled precast structural systems.

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Lindner, Marco, Konrad Vanselow, Sandra Gelbrich y Lothar Kroll. "Fibre-reinforced polymer stirrup for reinforcing concrete structures". Technologies for Lightweight Structures (TLS) 3, n.º 1 (24 de enero de 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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You, Young-Jun, Hyeong-Yeol Kim, Gum-Sung Ryu, Kyung-Taek Koh, Gi-Hong Ahn y Se-Hoon Kang. "Strengthening of Concrete Element with Precast Textile Reinforced Concrete Panel and Grouting Material". Materials 13, n.º 17 (1 de septiembre de 2020): 3856. http://dx.doi.org/10.3390/ma13173856.

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Textile reinforced concrete (TRC) has widely been used for strengthening work for deteriorated reinforced concrete (RC) structures. The structural strengthening often requires accelerated construction with the aid of precast or prefabricated elements. This study presents an innovative method to strengthen an RC slab-type element in flexure using a precast panel made of carbon TRC. A total of five RC slabs were fabricated to examine the flexural strengthening effect. Two of them were strengthened with the precast panel and grouting material and another set of two slabs was additionally strengthened by tensile steel reinforcement. The full-scale slab specimens were tested by a three-point bending test and the test results were compared with the theoretical solutions. The results revealed that the ultimate load of the specimens strengthened with the TRC panel increased by at least 1.5 times compared to that of the unstrengthened specimen. The application of the precast TRC panel and grouting material for the strengthening of a prototype RC structure verified its outstanding constructability.

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20

Saatcioglu, Murat, Denis Mitchell, René Tinawi, N. John Gardner, Anthony G. Gillies, Ahmed Ghobarah, Donald L. Anderson y David Lau. "The August 17, 1999, Kocaeli (Turkey) earthquake damage to structures". Canadian Journal of Civil Engineering 28, n.º 4 (1 de agosto de 2001): 715–37. http://dx.doi.org/10.1139/l01-043.

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The 1975 Turkish code provisions are first reviewed to provide the background for design and detailing of structures prior to the earthquake. The performance of reinforced concrete and masonry structures is described indicating many of the deficiencies in design, detailing, and construction execution. The behaviour of precast concrete structures, steel structures, and industrial facilities is also presented. The provisions of the 1997 Turkish building code are summarized and a description of new construction provides evidence of both excellent and poor construction practice. Some examples of retrofitting of damaged structures soon after the earthquake are also presented.Key words: seismic design, earthquake, Kocaeli, structures, codes, concrete, precast concrete.

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21

Nosenko, Viktor y Oleg Krivenko. "Influence of house bearing construction rigidi-ty of precast reinforced concrete on stress-strain state Continuous Flight Auger (CFA) piles foundations". Bases and Foundations, n.º 40 (4 de junio de 2020): 48–57. http://dx.doi.org/10.32347/0475-1132.40.2020.48-57.

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At present, the tendency to build multi-storey residential buildings has become widespread in Ukraine. This is due to a number of reasons: significant increase in land prices in cities, dense urban development and the availability of appropriate equipment for the construction of such structures. One of the most common materials for multi-storey buildings is monolithic reinforced concrete. The main advantage of monolithic structures is the possibility of free spatial planning and the possibility of uniform redistribution of forces in the elements of the frame - the house works as one rigid entire structure. On the other hand, such structures require a long construction time and appropriate highly qualified control of monolithic works. Therefore, as an alternative, prefabricated reinforced concrete structures are used to accelerate the pace of construction. In this work, the influence of the rigidity of a precast reinforced concrete house on the stress-strain state of CFA piles foundation is investigated. The stress-strain state of a precast reinforced concrete building with two basement options is analyzed: precast and monolithic. The numerical modeling of the interaction of the system elements is used as a research method: soil base - foundation - aboveground structure. It was found that the replacement in a prefabricated house only one basement floor of precast concrete on a monolithic one affects the redistribution of forces, so the self-supporting wall is loaded 2.6 times, and the busiest wall, which rests on both sides of the floor slab, is unloaded to 2.1 times. It was found that in the case of a basement made of precast reinforced concrete with a precast basement the difference efforts in pile heads (under the load-bearing walls) can differ 1.98 times, and in the case of a monolithic one 1.17 times. So it is mean, the monolithic foundation redistributed of efforts between the piles is more uniform. It is established that the monolithic reinforced concrete basement, in comparison with the prefabricated one, reduces the uneven settlement of the foundation by 2.4 times. When designing large-panel houses, it is advisable to provide a basement floor monolithic - this will allow to load the fundamental constructions more evenly, which in its reduction reduces the relative deformation of buildings and reduces their cost.

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Koyankin, A. A. y V. M. Mitasov. "Stressstrain state of cast-in-place and precast structure with loaded cast-in-place element". Vestnik Tomskogo gosudarstvennogo arkhitekturno-stroitel'nogo universiteta. JOURNAL of Construction and Architecture 23, n.º 3 (28 de junio de 2021): 129–42. http://dx.doi.org/10.31675/1607-1859-2021-23-3-129-142.

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The paper presents the strength analysis of cast-in-place and precast structures in accordance with regulatory documents, which require clarifications, since the properties of such structures distinguish them from conventional reinforced concrete structures. These properties include the beginning of the deformation process, ultimate strain, physical properties, and others. The strength analysis of cast-in-place and precast structure is conducted with regard to these properties.The proposed analysis is based on the load-bearing capacity exhaustion of deformed concrete or reinforcement and allows considering the different time of involvement in the deformation process of cast-in-place and precast structures as well different stress and strain properties of concrete. The experimental data are in good agreement with theoretical calculations.

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SOKOLOV, Boris, Vitaly TITAEV y Dmitry PASKHIN. "PRECAST SHELLS MADE OF UNITS BENT DURING FORMING". Bulletin of Science and Research Center “Stroitelstvo”, n.º 3 (30) (30 de agosto de 2021): 66–77. http://dx.doi.org/10.37538/2224-9494-2021-3(30)-66-77.

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In construction, thin-walled reinforced concrete spatial structures are used both for unique roofs of large-span buildings and for mass buildings of the pavilion type and small architectural forms. The most serious obstacle to the widespread application of economical thin-walled reinforced concrete structures is the shortcomings of the technology used for the manufacture and installation of prefabricated shell elements. The method of bending just formed flat flexible plates to give them a curved shape is one of the most promising technological methods that allow you to abandon the use of expensive metal forms of complex curved outlines, significantly simplify all production processes. The article describes the experience of research and development of structural decisions for spatial structures of building roofs with the use of unified rhombic elements made by the method of bending a flat just formed sheet on a flexible formwork.

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Kakharov, Zaytzhan Vasidovich y Nodirbek Bakhtiyor coal Kodirov. "ENERGY SAVINGS IN PRODUCTION PRECASTED CONCRETE". Chronos 6, n.º 10(60) (13 de octubre de 2021): 13–16. http://dx.doi.org/10.52013/2658-7556-60-10-3.

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This article discusses the problems of energy savings at enterprises for the production of precast concrete. The rational consumption of energy in the production of prefabricated reinforced concrete is considered, the costs of energy spent on the production of cement and reinforcement are taken into account, excluding excessive consumption of fuel, which leads to energy savings. To save energy resources, a bench technology for manufacturing prefabricated reinforced concrete structures was considered at the enterprises.

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25

Holý, Milan y Lukáš Vráblík. "The Timber-Precast UHPC Composite Connection". Solid State Phenomena 272 (febrero de 2018): 21–27. http://dx.doi.org/10.4028/www.scientific.net/ssp.272.21.

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This paper deals with the connection of timber beams and precast concrete slabs. The connection of timber and concrete has many advantages associated with the efficient use of both materials, not only in terms of their stress. Timber is a natural renewable material. It can be achieved some savings of volume of the concrete by its application and thereby also reducing of the environmental burden. By the combining of the timber and ultra-high performance concrete (UHPC), it can be designed very subtle, bearable, aesthetic and durable structures. The conventional timber-concrete composite structures are most often realized by joining of the timber beams and the cast in-situ reinforced concrete slabs. However, the cast in-situ slab is not very suitable for UHPC application and it has some structural disadvantages, in particular the need to protect the timber beams against moisture penetration from the fresh concrete mix, the need for formwork, etc. The prefabrication eliminates some disadvantages of the cast in-situ design, increases the quality of the structure and speeds up the construction process. In the case of the timber-concrete composite structures, the prefabrication has a positive impact on the reduction of the concrete shrinkage projections as the development of deflections and the redistribution of internal forces between the connected parts of the cross-section. Some special coupling elements must be used for connection in the case of precast slabs. This paper summarizes the research findings in the field of development of special coupling elements for composite timber-precast concrete structures. The development of the new coupling elements for pedestrian and cyclist timber-UHPC composite footbridges is presented.

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Tamrazyan, Ashot y Arman Minasyan. "The influence of depth of tensile concrete deterioration on the load bearing strength and deflections of corrosion-damaged floor slabs". MATEC Web of Conferences 251 (2018): 02012. http://dx.doi.org/10.1051/matecconf/201825102012.

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The paper considers the change of load-bearing strength and deflections of corrosion-damaged precast reinforced concrete floor slabs in the conditions of cyclic freezing-thawing in full-scale climatic conditions. The aim of the study is to determine the influence of the depth of tensile concrete deterioration on the change in load-bearing strength and deflections. Corrosion-damaged precast reinforced concrete floor slabs were selected and experimental investigation was performed. Based on the results of the study, the influence of the depth of deterioration of tensile zone of concrete on the load-bearing strength and deflections of structures was determined. At the same time, as the loads increase, deflections increase and the height of the compressive zone decreases. In the experimental investigation, changes of the load-bearing strength and deflections of precast reinforced concrete slabs were determined, depending on the depth of tensile concrete deterioration. The performed studies allow us to estimate the load-bearing strength and deflection values of corrosion-damaged reinforced concrete slabs depending on the relative value of the concrete deterioration in the tensile zone without performing additional experiments and calculations.

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27

Sangeetha, P. y M. Shanmugapriya. "Prediction of mechanical strength of polypropylene fibre reinforced concrete using artificial neural network". Gradjevinski materijali i konstrukcije 63, n.º 4 (2020): 79–86. http://dx.doi.org/10.5937/grmk2004079s.

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The usefulness of fibre reinforced concrete (FRC) in various civil engineering applications is indisputable. Fibre reinforced concrete has been successfully used so far in construction of structures like bridges, industrial structures, concrete, architectural panels, precast products, offshore structures and many other applications. This paper presents the study on the mechanical properties of the polypropylene fibre reinforced concrete. The parameters varied in the study include volume of fibre (0%, 0.5%, 1.0%, 1.5% & 2.0%) and the curing period (7 days and 14 days). From the study it is concluded that the further increases in the volume of fibre reduces the water cement ratio. The mechanical properties of the polypropylene fibre reinforced concrete were also predicted by using Artificial Neural Network (ANN) and found to have minimal error when compared to actual experimental results.

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Hery, Kristiyanto, Triwiyono Andreas, Muslikh y Saputra Ashar. "Beam-to-Beam Connection of Precast Concrete Structures: State of the Art". MATEC Web of Conferences 258 (2019): 04002. http://dx.doi.org/10.1051/matecconf/201925804002.

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The use of precast concrete is known to improve productivity, quality control, and cost efficiency in reinforced concrete structure. The Connection is the most important aspect of precast concrete structures. The connection transfers force between the precast components, determine strength, stiffness, and ductility of the whole structure. Providing joint in the beam-column connection region always cause difficulties during the erection stage. Relocation of the connection at a certain distance from the column to the beam span is an alternative solution that creates the beam-to-beam connection. It will be much easier to assemble the connection that consists of some joints. Research and application of the precast concrete beam-to-beam connection details have published since 1975. This paper reviews the state of the art of research and practical application of beam-to-beam connection system related to connection models, joint locations, and details. It concluded from the review that the developing research leads to improve the performance of earthquake resisting structures

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29

Koyankin, Alexandr y Valeriy Mitasov. "Assessment of structural reliability of precast concrete buildings". MATEC Web of Conferences 143 (2018): 01001. http://dx.doi.org/10.1051/matecconf/201814301001.

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Precast housing construction is currently being under rapid development, however, reliability of building structures made from precast reinforced concrete cannot be assessed rationally due to insufficient research data on that subject. In this regard, experimental and numerical studies were conducted to assess structural reliability of precast buildings as described in the given paper. Experimental studies of full-scale and model samples were conducted; numerical studies were held based on finite element models using “Lira” software. The objects under study included fragment of flooring of a building under construction, full-size fragment of flooring, full-scale models of precast cross-beams-to-columns joints and joints between hollow-core floor slabs and precast and cast-in-place cross-beams. Conducted research enabled to perform an objective assessment of structural reliability of precast buildings.

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Tang, Baijian, Jiawei Wang, Huiyuan Shi, Zhiyuan Xia, Yongjie Zhang y Li Chen. "Numerical Simulation Methodology for Prefabricated Shear Walls Considering Stochastic Defects in Grouting Materials". Buildings 12, n.º 11 (2 de noviembre de 2022): 1859. http://dx.doi.org/10.3390/buildings12111859.

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The most used connection form for reinforced steel bars is the grouting sleeve using cement-based grouting materials. Hence, the quality of the grouting sleeve connection determines whether the performance of a precast concrete structure is equivalent to that of a cast in situ concrete structure. However, several existing reasons, namely, insufficient grouting cement or poor construction controls and even stochastic bubble holes, lead to inevitable grouting defects. The behavior of precast concrete structures is affected dramatically. Considering the cost and efficiency of the analysis of precast concrete structures, the finite element method is still the most used method, but the simulation technology of structures considering stochastic defects in grouting materials is not sufficient. Herein, a simulation method considering stochastic defects in precast concrete structures is proposed, and the application of the method to grouting sleeves and shear wall structures is performed to verify its accuracy and feasibility. The construction of stochastic defects in grouting material is first realized through the Python scripter. Secondly, the mechanical parameters are obtained from the refined finite element analysis of grouting sleeves with material defects. Finally, based on the obtained mechanical properties of grouting sleeves, the behaviors of precast shear walls under blast loading are analyzed. The simulations of grouting sleeves under uniaxial tensile loading and precast concrete shear walls under blast loading both indicate that the proposed numerical method is feasible in solving the structural issues with stochastic defects in grouting materials.

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31

Poloz, Maxim A., Nikolay V. Frolov, Andrey V. Shevchenko y Jan Jimei. "Analysis of Prestressed Bent Precast-Cast-In-Situ Structures in Vlasov-Mileykovsky Method with Physical Non-Linearity of Material". Materials Science Forum 974 (diciembre de 2019): 601–7. http://dx.doi.org/10.4028/www.scientific.net/msf.974.601.

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Precast reinforced concrete structures with and without reinforcement pre-stressing are used both as newly designed independent ones and are the result of work to strengthen the existing structures by increasing the section. In both cases, the cross section of such elements is considered as a two-layer section, and the resulting composite element works under load under conditions distributed between the layers of internal forces, the mechanism and actual distribution of which depends on the physical and mechanical characteristics, the design scheme and the layers contact interaction parameters. When calculating and designing prestressed reinforced concrete precast-monolithic elements, the shear seam ductility is usually not paid much attention to, which complicates the structure actual stress-strain state analysis and contains a certain undiscovered potential of its rational design. One of the possible directions in solving the problem, which takes into account the contact seam shift, is the structural mechanics variation principles use in the calculation of structures such as rods of composite section. The questions of a composite reinforced concrete precast-monolithic rod of the variation principles of structural mechanics based on the method of V.Z. Vlasov - I.E. Mileykovsky in the displacements form in combination with the step-iterative method of calculation practical applicability in the structural analysis is considered in this work,. The numerical calculations results according to the proposed method are given. This allows to take into account the precast and monolithic layers shear connections specifics, to take practical account of weld compliance, and also to take into account the material characteristics’ physical non-linearity, which contributes to the precast monolithic structures rational design.

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32

Hassanli, Reza, Tom Vincent, Allan Manalo, Scott T. Smith, Aliakbar Gholampour, Rebecca Gravina y Yan Zhuge. "Connections in GFRP reinforced precast concrete frames". Composite Structures 276 (noviembre de 2021): 114540. http://dx.doi.org/10.1016/j.compstruct.2021.114540.

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33

KAPRIELOV, Simon, Andrey SHEYNFELD, Igor ARZUMANOV y Igor CHILIN. "NEW NATIONAL STANDARD FOR SELF-COMPACTING CONCRETE MIXES". Bulletin of Science and Research Center “Stroitelstvo”, n.º 3 (30) (30 de agosto de 2021): 30–40. http://dx.doi.org/10.37538/2224-9494-2021-3(30)-30-40.

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The information about the new national standard GOST R «Self-compacting concrete mixtures. Specifications», developed by the «Research Institute for Concrete and Reinforced Concrete» named after A.A. Gvozdev, of JSC «Research Center of Construction», is presented. The standard applies to ready-to-use selfcompacting concrete mixtures of heavyweight, fine-grained, light-weight and reactive powder concretes, as well as fiber reinforced concretes, for the production of monolithic or precast concrete structures and products, the shape and reinforcement of which makes it difficult to place and compaction of an ordinary concrete mixture. The standard establishes new terms and definitions, types and designations, uniform requirements for new technological characteristics (slump-flow, segregation, viscosity and flowability), acceptance rules and test methods, production and transportation processes, control and evaluation procedures conformity of quality indicators of self-compacting concrete mixes.

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34

Koh, Taehoon y Moochul Shin. "Field Tests on Eco-Friendly Railway Precast Concrete Slab". Applied Sciences 10, n.º 12 (16 de junio de 2020): 4140. http://dx.doi.org/10.3390/app10124140.

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This study focuses on evaluating the field performance of a newly developed eco-friendly precast concrete slab track structure for railway/subway systems in Seoul, South Korea. Although Ballasted railway track structures are one of the most common track structures in the railway industry, they have some drawbacks including higher maintenance cost, un-uniform supports, and a high level of noise and vibration. However, a ballastless (slab-based) track structure system requires less maintenance and uniform support conditions, as well as several ballastless structure systems developed for high-speed trains. The Seoul Metro subway in South Korea has developed a ballastless reinforced concrete (RC) slab railway system using a type of conventional concrete. This study presents a ballastless precast concrete slab using a newly developed eco-friendly concrete, which can significantly improve structural performances and the manufacturability of a railway track structure system. This study evaluates the field performance of the eco-friendly concrete slab system deployed in one of the existing tunnel sections of the Seoul Metro subway system. A total of 10 m long slab sections including a 5 m long eco-friendly “ballasted track to slab track (B2S)” panels section and a 5 m long conventional B2S panels section are installed and monitored side by side. Field tests are performed to measure the level of noise, vibration, dynamic wheel load, rail displacement, and rail stress. The field measurements from the eco-friendly B2S section are compared to those of the conventional reinforced concrete slab track systems. The results show that the performance of the new B2S system using the eco-friendly concrete is comparable and/or superior to the conventional system.

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35

Yan, Qiushi, Bowen Sun, Xuemei Liu y Jun Wu. "The effect of assembling location on the performance of precast concrete beam under impact load". Advances in Structural Engineering 21, n.º 8 (27 de octubre de 2017): 1211–22. http://dx.doi.org/10.1177/1369433217737119.

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With incorporation of assembling joints, precast concrete beams could behave very differently in resisting both static and dynamic loads in comparison to conventional reinforced concrete beams. With no research available on the dynamic behavior of precast concrete beams under impact load, a combined experimental and numerical study is conducted to investigate the dynamic response of precast concrete beams under impact load. The results were also compared with reinforced concrete beams. Four groups of concrete beams were tested with all beams designed with the same reinforcement, but different assembling locations were considered for precast concrete beams. The effects of the assembling location in resisting drop weight impact of precast concrete beams were analyzed. The influence of impact mass and impact velocity on the impact resistance of precast concrete beams were also investigated. The results revealed that the further the assembling location is away from the impact location, the closer the mechanical performance of the precast concrete beam is to that of the reinforced concrete beam. When the assembling location and the impact location coincided, the assembling region suffered from severe local damages. With increased impact velocity and impact energy, the damage mode of the precast concrete beams may change gradually from bending failure to bending–shear failure and eventually to local failure. In addition, the bonding around the assembling interface was found to be effective to resist drop weight impact load regardless of the magnitude of the impact velocity and energy.

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36

Ohta, Y. "Handing Down of Super High-rise Reinforced Concrete Structures Technology and Precast Reinforced Concrete Technology and Future Efforts". Concrete Journal 59, n.º 1 (2021): 33–37. http://dx.doi.org/10.3151/coj.59.1_33.

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37

Park, Bob. "Some controversial aspects of the seismic design of reinforced concrete building structures". Bulletin of the New Zealand Society for Earthquake Engineering 36, n.º 3 (30 de septiembre de 2003): 165–88. http://dx.doi.org/10.5459/bnzsee.36.3.165-188.

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Significant differences exist between the recommendations for seismic design of the codes and guidelines for reinforced concrete of different countries. Performance criteria for building structure to avoid unacceptable damage during various levels of earthquake hazard need to be refined. More accurate recommendation for the effective flexural rigidity of reinforced concrete members are required for linear elastic structural analysis to enable better estimates of the periods of vibration and the lateral deflections of statically indeterminate structures including the effects of cracking of concrete. Current code recommended values for flexural rigidity will generally lead to estimates of the periods of vibration and lateral deflections, which are on the low side. The capacity design approach to ensure the most appropriate mechanism of yielding will occur in the event of a severe earthquake is generally recognized by codes but to varying degrees of clarity, and the degrees to which capacity design is incorporated in each code varies significantly. High strength concrete and high strength non-prestressed steel reinforcement can be used in the design of buildings but the brittle behaviour of high strength concrete and the unusable yield strength of high strength steel reinforcement need to be considered. Important differences between codes exist in the rules for the quantity of confining reinforcement placed in reinforced concrete columns to ensure ductile behaviour. Significant differences also exist between the quantities of shear and confining reinforcement required in beam-column joints and in the anchorage of length of longitudinal reinforcement passing through beam-column joints. Precast concrete structures can be designed successfully for earthquake resistance but design codes in seismic regions contain provisions for precast concrete to varying degrees.

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38

Krasnoshchekov, Yu V. "Protection against progressive collapse of buildings with precast reinforced concrete floors". Russian Automobile and Highway Industry Journal 19, n.º 2 (24 de mayo de 2022): 290–99. http://dx.doi.org/10.26518/2071-7296-2022-19-2-290-299.

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Introduction. The results of the studies analysis on the protection of multi-storey buildings from progressive collapse are presented, which indicates insufficient attention to structural systems made of precast reinforced concrete, as a result of which design standards orient the designer to the use of not always effective monolithic structures. In particular, the problem of protection against progressive collapse with the exclusion of prefabricated crossbars of floors and coatings has not been practically studied. The purpose of the study is to develop a method for calculating a continuous system of hollow plates made by the method of formless molding.Materials and methods. When designing the protection of multi-storey buildings from prefabricated elements, a static calculation is usually carried out with the exception of vertical structures (walls, columns) and the reinforcement of floor crossbars and coatings by ensuring their continuity. There are constructive methods of reinforcing prefabricated floors by creating continuous plates of adjacent spans with the help of connecting elements made of plastic reinforcing steel, but the calculation of such systems has not been developed. A method for calculating a system of two plates according to a rigid thread scheme is proposed.Conclusions. Currently, theoretical methods have been developed to solve various problems of protecting buildings and structures from progressive collapse. However, there are many design requirements for the protection of multistorey buildings from progressive collapse, which have not yet received experimental and theoretical confirmation for the effective solution of practical problems. It seems that in this article one of these problems is partially solved.

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Khan, Sadaqat U., M. F. Nuruddin, T. Ayub y N. Shafiq. "Effects of Ferrocement in Strengthening the Serviceability Properties of Reinforced Concrete Structures". Advanced Materials Research 690-693 (mayo de 2013): 686–90. http://dx.doi.org/10.4028/www.scientific.net/amr.690-693.686.

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The aim of this paper is to investigate the serviceability performance of RC beams strengthened through two Ferrocement strengthening techniques as Cast in situ Wire-mesh layers and precast Ferrocement Laminates. To assess the effectiveness of these strengthening techniques, eight (08) RC beams have been intentionally designed and detailed as a tension-controlled section and tested under two-point loading up to service load of 40 kN. Then, beams were strengthened by Cast in situ Wire-mesh layers and by precast Ferrocement Laminates. Experimental results in terms of stiffness have been compared within and across the groups to assess the effect of variation of development length and no. of wire-mesh layers.

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40

Cleland, Ned M. y Thomas T. Baber. "Behavior of Precast Reinforced Concrete Ledger Beams". PCI Journal 31, n.º 2 (1 de marzo de 1986): 96–117. http://dx.doi.org/10.15554/pcij.03011986.96.117.

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41

Brunesi, Emanuele, Roberto Nascimbene, Davide Bolognini y Davide Bellotti. "Experimental investigation of the cyclic response of reinforced precast concrete framed structures". PCI Journal 60, n.º 2 (1 de marzo de 2015): 57–79. http://dx.doi.org/10.15554/pcij.03012015.57.79.

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42

Davidyuk, Artem y 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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43

Kim, Seungho, Dong-Eun Lee, Yonggu Kim y Sangyong Kim. "Development and Application of Precast Concrete Double Wall System to Improve Productivity of Retaining Wall Construction". Sustainability 12, n.º 8 (23 de abril de 2020): 3454. http://dx.doi.org/10.3390/su12083454.

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The construction of most apartment underground parking lots utilizes reinforced concrete (RC) structures composed mainly of rebar work and formwork. RC structures lower construction efficiency and significantly delay the construction because they require a large number of temporary materials and wooden formwork. In this study, a precast concrete double wall (PCDW) system was developed to address the existing problems of RC structures and to improve the productivity of retaining wall construction. PCDW is a precast concrete (PC) wall in which two thin concrete panels are connected parallel to each other with truss-shaped reinforcement between them. PCDW can contribute to securing integrity, reducing the delay in construction, and improving quality. An overall process for the member design and construction stage of the PCDW system was proposed, and its improvement effects were examined regarding various aspects in comparison to the RC method.

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44

Kaverzina, Liudmila, Galina Kovalenko, Irina Dudina y Oleg Belskii. "Cost efficiency assessment of automated quality control of precast structures". MATEC Web of Conferences 143 (2018): 04006. http://dx.doi.org/10.1051/matecconf/201814304006.

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Relevance of the research is conditioned by the necessity to enhance the factory quality control of reinforced concrete structures based on integral assessment of their reliability. The current system of selective quality control of precast concrete structures does not provide reliability assurance of the whole lot of products. The present research aims to develop operational procedure and consider economic feasibility of automated quality control of precast RC structures. Quality control is performed each shift according to the developed software system based on probabilistic methods considering statistic variability of the controlled parameters. The critical criterion of operational integrity of structures is integral assessment of the reliability indicators. The following theoretical research methods were used in the study: probabilistic-statistical, methods of system and economic analysis. Validity of the obtained results and economic feasibility were proved by experimental studies including full-scale tests.

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45

Šimek, Ondřej, Miloš Zich, Miloslav Janda y Radim Nečas. "The Influence of Various Types of Reinforcement of the Concrete Pillars of Precast Walls with an Opening". Solid State Phenomena 322 (9 de agosto de 2021): 94–99. http://dx.doi.org/10.4028/www.scientific.net/ssp.322.94.

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The subject of the article is a comparison of the precast reinforced concrete pillars with different types of reinforcement. These are the pillars simulating parts of walls that can, for example, form in the precast wall of residential buildings after an opening has been carved. The pillars are variously reinforced: from the simple reinforcement with wire mesh to the reinforcement with standard reinforcement bars. Behavior of the pillars, that have been subjected to two types of experiments in the past, is verified by software for non-linear analysis for concrete structures. Depending on the types of loading, the ultimate limit state, deformation and stress state of the individual pillars are studied.

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46

Ilki, Alper y Ugur Demir. "FACTORS AFFECTING SEISMIC BEHAVIOUR OF REINFORCED CONCRETE STRUCTURES AFTER FIRE EXPOSURE". NED University Journal of Research 1, Special Issue on First SACEE'19 (1 de enero de 2019): 31–41. http://dx.doi.org/10.35453/nedjr-stmech-2019-0003.

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In the areas under high earthquake risk, the impact of fire damage on the seismic performance of the reinforced concrete (RC) structures ought to be realistically taken into account while assessing the fire damage to develop reuse/repair/replace strategies through the remaining service life. In the scope of this study, a literature review is conducted on the changes of mechanical characteristics of concrete and reinforcement caused by a fire with a particular emphasis on the post-cooling stage. Post-cooling behaviour of RC members is different than the behaviour under elevated temperatures and hence it is of vital importance on structural seismic performance assessment after a fire. Apart from material-wise assessment methodologies, post-fire seismic performance of RC structural members is also discussed through post-fire simulated seismic loading tests conducted on full-scale cast-in-place and precast columns. The test results pointed out to a reduction in lateral load bearing capacity of the cast-in-place columns subjected to fire whereas fire-exposed precast columns demonstrated better performance in terms of residual lateral load capacity due to the lower axial load and larger heights. All columns exhibited satisfactory performance in terms of ductility.

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47

Tusnin, Alexander y Alexey Kolyago. "The calculation of anchors in steel-concrete overlaps with precast slab". E3S Web of Conferences 97 (2019): 06022. http://dx.doi.org/10.1051/e3sconf/20199706022.

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Reinforced concrete floors and steel beams are widely used in buildings and structures for various purposes. Reinforced concrete overlaps can be cast-in or precast of hollow-core slabs. The most effective floors in which the concrete slab is located in the compressed area of cross-section, in steel beams in the tension zone, and shifting forces, arising between concrete slab and the steel beam, are perceived by anchors. Precast slabs in comparison with cast-in ones have less labor-intensive performance, the beam spacing is equal to the span of reinforced concrete slabs, there are no intermediate beams in such overlaps, that allows to reduce the floor thickness. The inclusion of precast in steel-concrete cross-section requires joints with steel beams, which requires using of special anchors. Anchor perceives shear forces and ensures the joint operation of the plate and the steel beam. In addition, for beams with narrow flange, the anchor device can provide the required width of the support slabs. The calculation of the attachment points of the anchors to the steel beam is carried out using three variants of calculation methods, which allow to determine the forces acting on the anchor. For practical application, a wire-element model has been proposed and managed to get forces in a steel beam, slab and anchors the width of the slab recommended by the standards should be included in the calculation model.

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48

Magliulo, Gennaro, Marianna Ercolino, Crescenzo Petrone, Orsola Coppola y Gaetano Manfredi. "The Emilia Earthquake: Seismic Performance of Precast Reinforced Concrete Buildings". Earthquake Spectra 30, n.º 2 (mayo de 2014): 891–912. http://dx.doi.org/10.1193/091012eqs285m.

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On 20 and 29 May 2012, two earthquakes of MW5.9 and MW5.8 occurred in the Emilia region of northern Italy, one of the most developed industrial centers in the country. A complete photographic report collected in the epicentral zone shows the seismic vulnerability of precast structures, the damage to which is mainly caused by connection systems. Indeed, the main recorded damage is either the loss of support of structural horizontal elements, due to the failure of friction beam-to-column and roof-to-beam connections, or the collapse of the cladding panels, due to the failure of the panel-to-structure connections. The damage can be explained by the intensity of the recorded seismic event and by the exclusion of the epicentral region from the seismic areas recognized by the Italian building code up to 2003. Simple considerations related to the recorded acceleration spectra allow motivating the extensive damage due to the loss of support.

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49

Sayed-Ahmed, Ezzeldin Y., Amr H. Riad y Nigel G. Shrive. "Flexural strengthening of precast reinforced concrete bridge girders using bonded carbon fibre reinforced polymer strips or external post-tensioning". Canadian Journal of Civil Engineering 31, n.º 3 (1 de junio de 2004): 499–512. http://dx.doi.org/10.1139/l04-005.

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Strengthening of reinforced concrete bridge girders has become a major concern. Many reinforced concrete highway bridges were constructed in Canada using precast reinforced concrete girders, and currently many of them need rehabilitation. Thus, two techniques for flexural strengthening of precast reinforced concrete bridge girders (HC-type) were investigated experimentally. The first technique involved bonding carbon fibre reinforced polymer (CFRP) strips to the soffits of the girders. The second technique was classical external post-tensioning with steel bars. A simple, yet innovative method was developed for applying the external prestressing to these girders. The experimental investigation was performed on full-scale girders from a dismantled bridge in Alberta (Canada). Outcomes of the experimental investigation led to the conclusion that classical methods of flexural strengthening (e.g., external prestressing) should not be completely disregarded. Also, an additional mode of failure needs to be added to currently available prediction models for estimating the gain in flexural strength of reinforced concrete girders retrofitted using bonded CFRP strips.Key words: bridges, CFRP, flexure strengthening, precast girders, post tension, prestressing, rehabilitation.

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50

Baran, M., D. Okuyucu, M. Susoy y T. Tankut. "Seismic strengthening of reinforced concrete frames by precast concrete panels". Magazine of Concrete Research 63, n.º 5 (mayo de 2011): 321–32. http://dx.doi.org/10.1680/macr.10.00030.

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