Journal articles: 'Existing Reinforced Concrete'

1

Patil, K. S., and S. S. Dhanaji. "Retrofitting Strategies For Earthquake Safe Existing Reinforced Concrete Building: an Overview." Journal of Advances and Scholarly Researches in Allied Education 15, no. 2 (April 1, 2018): 452–54. http://dx.doi.org/10.29070/15/56866.

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An, Xin Zheng, Cheng Yi, and Rui Xue Du. "Performance Deterioration Behavior of Existing Reinforced Concrete Bridges." Advanced Materials Research 79-82 (August 2009): 1367–70. http://dx.doi.org/10.4028/www.scientific.net/amr.79-82.1367.

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The analyses of concrete from a bridge in Handan district shows that most bridges concrete should have cracked. The study of the technical measures against the performance deterioration of existing reinforced concrete bridges will undoubtedly become an imperative issue. In recent years, lots of bridges have been built in Handan. We choose a reinforced concrete bridge to investigate the effect of the effective member stiffness degradation and durability degradation induced by vehicle overload, vehicle overflow, rebar corrosion, and concrete deterioration on highway reinforced concrete bridges. And Static loading test was conducted at its middle span. Based on the test data in different circumstances, the seriousness of vehicle overload is discussed. In consequence, the performance of highway reinforced concrete bridges on stiffness degradation and durability degradation is more serious compared with the bridge under the condition of non-overloading. The results show that the process of rebar corrosion in highway reinforced concrete bridges is sped up under the condition of vehicle overload and vehicle overflow on the highway reinforced concrete bridges, which decreases the durability of the bridge structure, and the speed of the durability degradation increases as time goes on. The paper conclusion is instructive for the construction and maintenance of bridge.

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Wang, Chung Sheng, Xiao Hong Dong, Wen Hui Miao, and Gan Li. "Fatigue Safety Evaluation of Existing Reinforced Concrete Bridges." Key Engineering Materials 413-414 (June 2009): 749–56. http://dx.doi.org/10.4028/www.scientific.net/kem.413-414.749.

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Generally, fatigue has not been considered as a key problem in the design of reinforced concrete bridges. Until the 1960s, reinforcement was mild steel and the stresses permitted in the steel bar and the concrete were such that fatigue and fracture failure was believed to be impossible. With the developments of reinforced concrete structures, higher working stresses were permitted and, in particular, high yield reinforcing bars were introduced. Design rules were issued to control cracking and to prohibit welding of reinforcement unless the risk of fatigue was negligible. In recent years, great deals of researches have been carried out, leading to a better understanding of the fatigue behaviors in concrete structures. Some studies showed that fatigue could occur in reinforced concrete structures in combination with other causes of deterioration. In the past eight years, considerable increases in traffic intensity and wheel loads have caused obviously fatigue damage in reinforced concrete structures in China. Some reinforced concrete bridges were damaged seriously, leading to the whole bridge collapse sometimes because of overloading and oversize trucks. So how to evaluate the fatigue safety of existing reinforced concrete bridges is an urgent problem in China. In the current paper, the assessment models of existing reinforced concrete bridges based on S-N curve and fracture mechanics approach were proposed considering the effect of overloading and oversize trucks. Finally the assessment method based on S-N curve and in-situ monitoring data was applied to a case study bridge.

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Elwood, Kenneth J. "Modelling failures in existing reinforced concrete columns." Canadian Journal of Civil Engineering 31, no. 5 (October 1, 2004): 846–59. http://dx.doi.org/10.1139/l04-040.

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Experimental research and post-earthquake reconnaissance have demonstrated that reinforced concrete columns with light or widely spaced transverse reinforcement are vulnerable to shear failure, and in turn, axial failure during earthquakes. Based on experimental data, failure surfaces have been used to define the onset of shear and axial failure for such columns. After the response of the column intersects the failure surface, the shear or axial strength of the column begins to degrade. This paper introduces a uniaxial material model that incorporates the failure surfaces and the subsequent strength degradation. When used in series with a beam-column element, the uniaxial material model can adequately capture the response of reinforced concrete columns during shear and axial load failure. The performance of the analytical model is compared with results from shake table tests.Key words: shear failure, axial failure, beam-column elements, failure surface, earthquakes, reinforced concrete, columns, collapse, structural analysis.

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Travush, Vladimir, and Vasily Murashkin. "CONCRETE DEFORMATION MODEL FOR RECONSTRUCTED REINFORCED CONCRETE." International Journal for Computational Civil and Structural Engineering 18, no. 4 (December 28, 2022): 132–37. http://dx.doi.org/10.22337/2587-9618-2022-18-4-132-137.

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During the reconstruction, or upon expiration of the service life, as well as after external impact, reinforced concrete structures require examination and verification calculations. Existing diagrams of concrete deformation are focused on designing new structures and are not adapted to the concretes of the reconstructed structures. Using the world experience in describing alloy deformation, the concrete deformation model based on using the Arrhenius equation is proposed in this article. A technique for creating an individual deformations model during the reconstruction is demonstrated on a specific example. The physical meaning of the coefficients used in the proposed model is illustrated. Examples confirming the adequacy of the proposed concrete deformations model during the reconstruction are given.

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Peng, Wei, Wen Ya Ye, Jia Jia, Zhao Hui Lu, and Hai Tao Hou. "Reliability Assessment of Existing Reinforced Concrete Arch Bridge." Applied Mechanics and Materials 405-408 (September 2013): 1687–90. http://dx.doi.org/10.4028/www.scientific.net/amm.405-408.1687.

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A finite element model of an existing reinforced concrete arch bridge was established. The reliability index was investigated based on the PDF module in ANSYS software. Taking the maximum concrete stress and tendon stress as limit state, the limit state functions of main arch, upright column and deck are established respectively. There are taken as series system to study the bridge system reliability according to the structural characteristics of reinforced concrete arch bridge. The lowest reliability index superstructure is selected as the whole structure reliability index. Based on JC method and made-up MATLAB program, the reliability index of the example bridge is calculated.

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Lynn, Abraham C., Jack P. Moehle, Stephen A. Mahin, and William T. Holmes. "Seismic Evaluation of Existing Reinforced Concrete Building Columns." Earthquake Spectra 12, no. 4 (November 1996): 715–39. http://dx.doi.org/10.1193/1.1585907.

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Past earthquakes have emphasized the vulnerability of reinforced concrete columns having details typical of those built before the mid-1970's. These columns are susceptible to axial-flexural, shear, and bond failures, which subsequently may lead to severe damage or collapse of the building. Research was undertaken to investigate the lateral and vertical load-resisting behavior of reinforced concrete columns typical of pre-1970's construction. Eight full-scale specimens were constructed and were loaded with constant axial load and increasing cyclic lateral displacement increments until failure. Test data are presented and compared with behavior estimated by using various evaluation methods.

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Han, Jian Qiang, Peng Cheng Dong, and Yan Rong Zhang. "Durability Testing of the Existing Reinforced Concrete Structures." Applied Mechanics and Materials 256-259 (December 2012): 884–87. http://dx.doi.org/10.4028/www.scientific.net/amm.256-259.884.

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The ability to structure durability refers to the concrete structure in the natural environment, the role of the environment and material internal factors in the design requirements of the target period do not need to spend a lot of money reinforcement processing to maintain its safety, function and appearance requirements. . With the continuous development and transformation of China’s urban scale, a large number of existing structures by the post-test, further reinforcement of the design and reconstruction of this paper, the actual project to detect and evaluate the durability of reinforced concrete structures, reinforcement of existing buildings in the future and the transformation of the former’s identification with a certain reference value.

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9

GHOBARAH, A., N. M. ALY, and M. EL-ATTAR. "SEISMIC RELIABILITY ASSESSMENT OF EXISTING REINFORCED CONCRETE BUILDINGS." Journal of Earthquake Engineering 2, no. 4 (October 1998): 569–92. http://dx.doi.org/10.1080/13632469809350335.

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10

Schläfli, Max, and Eugen Brühwiler. "Fatigue of existing reinforced concrete bridge deck slabs." Engineering Structures 20, no. 11 (November 1998): 991–98. http://dx.doi.org/10.1016/s0141-0296(97)00194-6.

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11

Utkin, Vladimir S., and Sergey A. Solovyev. "RELIABILITY ANALYSIS OF EXISTING REINFORCED CONCRETE BEAMS ON NORMAL CRACK LENGTH CRITERION." International Journal for Computational Civil and Structural Engineering 13, no. 2 (June 30, 2017): 56–63. http://dx.doi.org/10.22337/2587-9618-2017-13-2-56-63.

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The article discusses a problem of the crack length influence on the reliability (safety) of reinforced concrete beams under conditions of limited statistical information about controlled parameters in the design mathematical models of limit state. Numerical examples revealed the possibility of practical application of the reliability analysis methods for inspections and determining the category of the technical condition of buildings and structures. The article offers the methods for reliability (probability of non-failure) analysis and the residual resource of reinforced concrete beams according to the criterion of the normal crack length in the tensile zone of reinforced concrete beams. The methods of reliability analysis constructed on the basis of possibility theory and fuzzy set theory. The algorithms of reliability analysis of reinforced concrete beams are presented on numerical examples of reliability analysis.

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12

Panfilov, Denis, Alexander Pischulev, and Yuriy Zhiltsov. "Stress-strain behaviour of pre-stressed slabs of off-shuttering formation reinforced by carbon fiber." MATEC Web of Conferences 196 (2018): 02016. http://dx.doi.org/10.1051/matecconf/201819602016.

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The paper presents calculations result of an assembled reinforced concrete hollow core slab of off-shuttering formation which has been reinforced with pre-stressed wire in its top and bottom areas reinforced with carbon fiber, in their turn. The research also examines the existing practice of using carbon fiber as reinforcement elements of reinforced concrete structures, existing specification documents regulating carbon fiber application of carbon in the Russian Federation as well as specification documents containing information about carbon fiber strength and stress-strain properties. The article contains the information on the scheme of loading, conditions of the slab fastening, geometrical characteristics of floor slab panels, physical characteristics of concrete and reinforcement of the experimental sample; technical characteristics of carbon reinforcement elements. The research results are represented as graphs of variance of construction deflections under loading in operating conditions of a slab wIth and without cracks before its reinforcement, and also in the moment of reinforcement. The research shows that using of carbon fiber to reinforce flexural elements with preliminary stress allows to increase rigidity and crack resistance of reinforced concrete elements.

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13

Anand, Praveen, and Ajay Kumar Sinha. "Effect of Reinforced Concrete Jacketing on Axial Load Capacity of Reinforced Concrete Column." Civil Engineering Journal 6, no. 7 (July 1, 2020): 1266–72. http://dx.doi.org/10.28991/cej-2020-03091546.

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Whenever a member of a structure becomes structurally deficient, it becomes vulnerable to the existing load and for the additional loads that it may be subjected to in the coming future. Since columns are the most important structural element, the structural retrofit of columns, relative to other structural elements is of prime importance. This study intends to investigate the performance and behaviour of an RC column jacketed with Reinforced Concrete columns under axial loads. The objective of this paper is to find out the efficiency of RC jacket in enhancing the strength of an existing RC column. A mathematical design based upon Indian Standards codes has been designed to identify the behaviour of jacketed RC columns. This has been followed by a finite element based numerical simulation using the same material properties as used in the process of designing. The simulation has been done in ABAQUS software with appropriate contact modelling. The analytical model considers that there is no bond slippage between the existing and new concrete surface i.e. the bond between the existing and new concrete is assumed to be perfect. This perfect bond between the surfaces has been modelled by using appropriate constraints in ABAQUS software. The finite element models show fair agreement with the designed values in terms of ultimate capacity and failure mode. The load bearing capacity enhancement of the RC jacketed column has been found to increase substantially. The enhancement capacity results obtained from the finite element software differs about 16-25% from the design values.

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14

Cleven, Simon, Michael Raupach, and Thomas Matschei. "A New Method to Determine the Steel Fibre Content of Existing Structures—Evaluation and Validation." Applied Sciences 12, no. 1 (January 4, 2022): 454. http://dx.doi.org/10.3390/app12010454.

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The in-situ measurement of the content and orientation of steel fibres in concrete structures is of great importance for the assessment of their specific mechanical properties, especially in the case of repair. For existing structures, the actual fibre content as well as the orientation of the fibres, which is based on many factors such as casting or compacting direction, is typically unknown. For structural maintenance or rehabilitation, those factors have to be determined in order to apply meaningful structural design calculations and plan necessary strengthening methods. For this reason, a new method based on the analysis of drilling cores of concrete structures has been established. The newly developed non-destructive test setup used in this research consists of a framework for cylindrical specimens in combination with an LCR meter to determine the electrical resistance of the fibre reinforced concrete. In combination with a suitable FEM model, concretes with fibre contents up 80 kg/m3 were analysed to derive a first model to assess the actual fibre content of steel fibre reinforced concretes. After a calibration of the literature’s equation by use of an adjusted aspect ratio for the analysis of drilling cores, the estimation of the fibre content is possible with high accuracy for the tested material combination. The results show that the newly developed test method is suitable for the rapid and non-destructive structural diagnosis of the fibre content of steel fibre reinforced concrete based on drilling cores using electrical resistivity measurements.

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15

Yin, Xiao San, Shi Feng Zhai, and Tian Niu Gong. "Application of Self-Compacting Concrete in Strengthening of Existing Reinforced Concrete Column." Advanced Materials Research 476-478 (February 2012): 1722–25. http://dx.doi.org/10.4028/www.scientific.net/amr.476-478.1722.

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The use of self-compacting concrete (SCC) is spreading worldwide due to its attractive properties in the fresh state as well as after hardening. Two application examples were introduced, one was reinforced concrete (RC) column strengthening with reinforced self-compacting concrete, and the other was with steel jacket and SCC. Economical and social benefits of the two application examples were analyzed. Project examples and applicable analysis show that RC column strengthening with SCC has attractive advantage, such as economy of technique, convenient construction, good construction quality, as well as bearing capacity improved significantly. The second strengthening method can make the best of advantage of SCC and steel material, and has strong global performance, high utilization ratio of the additional new materials, seismic behavior improved obviously, and so on.

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16

Beßling, Markus, Melanie Groh, Viola Koch, Michael Auras, Jeanette Orlowsky, and Bernhard Middendorf. "Repair and Protection of Existing Steel-Reinforced Concrete Structures with High-Strength, Textile-Reinforced Mortars." Buildings 12, no. 10 (October 5, 2022): 1615. http://dx.doi.org/10.3390/buildings12101615.

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Numerous concrete monuments built in the High Modern Era (turn of the 20th century until the 1970s) must now be repaired for preservation. Traditional concrete repair according to current guidelines involves considerable material removal, changing the appearance of the existing structure. With a combination of the material properties of high-/ultra-high-performance concrete (HPC/UHPC) with its dense microstructure and corrosion-free textile reinforcement (carbon and basalt), a high-performance mortar repair system can be developed. Such a system allows for concrete repairs with minimal material loss by using very thin layers that are durable and do not change the architectural character of the repaired monument. For the investigation of the load-bearing behaviour of a structural repair system using textile-reinforced, high-performance mortar, 20 mm thick slabs were produced and mechanically characterized. In the next step, the proposed repair system was applied to 70 mm thick old concrete slabs. The results show that a high surface tensile strength of 2.9 MPa was obtained. In a further step, the system will be applied to concrete pillars of transmission tower in Berus, adapted in terms of colour and structure and installed for long-term monitoring.

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Orlowsky, Jeanette, Markus Beßling, and Vitalii Kryzhanovskyi. "Prospects for the Use of Textile-Reinforced Concrete in Buildings and Structures Maintenance." Buildings 13, no. 1 (January 10, 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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Chen, Xu Yong, and Xiao Xie. "Research on Masonry Arch-Bridges Reinforcement and Reconstruction Methods." Applied Mechanics and Materials 501-504 (January 2014): 1152–56. http://dx.doi.org/10.4028/www.scientific.net/amm.501-504.1152.

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We analyze existing masonry arch-bridges and corresponding reinforcement methods in this paper and bring about the method of using strip-shaped outer-wrap reinforced concrete with chemically planted bar to improve the new and old concretes cooperative work so as to strengthen the wholeness and improve impermeability of the bridge. We also compare two experiments on one actual bridge of 30 cm strip-shaped outer-wrap reinforced concrete in the main arch ring and 20 cm global outer-wrap reinforcement concrete, of which the data shows the superiority of strip-shaped outer-wrap reinforced concrete for it strengthens both the bridge floor and bottom structure and improve the load capacity.

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Dan, Sorin, Corneliu Bob, Catalin Badea, Daniel Dan, Constantin Florescu, Liliana Cotoarba, Vasile Pode, and Aurelian Gruin. "Carbon Fiber Reinforced Polymers Used for Strengthening of Existing Reinforced Concrete Structures." Materiale Plastice 55, no. 4 (December 30, 2018): 536–40. http://dx.doi.org/10.37358/mp.18.4.5069.

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The paper deals with some aspects regarding the behavior of modern and efficient solutions - for rehabilitation of reinforced concrete framed structures. The paper is devoted to experimental studies on carbon fiber reinforced polymer (CFRP) systems used as strengthening solution for reinforced concrete (RC) frames assumed as existing structures, which were tested as un-strengthened and as (CFRP) strengthened structures. Single span and single story frames (scale 1:2) were designed and detailed according to the Romanian design codes from 1970s under which seismic design was inadequate. The RC design and the magnitude of applied forces were ensuring the failure mechanism, of non-strengthened RC frames, by plastic hinges at columns ends. Then the columns were strengthened by using CFRP materials. The experimental program emphasized some important aspects regarding the behavior and failure by debonding of CFRP strengthening materials applied to RC frames. The analysis of experimental data and theoretical values showed up an increase of resistance and stiffness achieved by strengthening.

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20

Lv, Li Bin, Mei Du, and Yong Xun. "Design and Production of Pre-Stressed Carbon Fabric Used in Fabric Reinforced Concrete Board." Applied Mechanics and Materials 174-177 (May 2012): 900–904. http://dx.doi.org/10.4028/www.scientific.net/amm.174-177.900.

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Pre-stressed fabric reinforced concrete sheet is used to make permanent model or to reinforce the existing buildings, it will make the surface of reinforced concrete with steel bar tightness and better cracking resistance, it is beneficial to fully manifest the effect of high strength and high modulus before the sheet cracking; the pre-stressed method improves sheet rigidity, it is beneficial for the sheet to cooperate with structure of reinforced concrete. The paper introduced the designing process of carbon/glass braided fabric composite material, and illuminated selecting raw material, means of making fabric, specification and selecting impregnating agent, meanwhile it made simple measurement to the fabric.

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21

Araki, H., M. Neguchi, and K. Minami. "Possibility of Retrofit of Existing Reinforced Concrete Buildings with Low Strength Concrete." Concrete Journal 48, no. 7 (2010): 3–8. http://dx.doi.org/10.3151/coj.48.7_3.

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Araki, H., M. Neguchi, and K. Minami. "Direction in Retrofitting of Existing Reinforced Concrete Buildings with Low Strength Concrete." Concrete Journal 52, no. 2 (2014): 151–56. http://dx.doi.org/10.3151/coj.52.151.

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23

Marková, Jana, Milan Holický, Karel Jung, and Miroslav Sýkora. "Reliability of existing reinforced concrete slabs exposed to punching shear." Acta Polytechnica CTU Proceedings 36 (August 18, 2022): 119–26. http://dx.doi.org/10.14311/app.2022.36.0119.

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Selected standardised models for the verification of punching shear in reinforced concrete structures are applied for the probabilistic assessment of their reliability level. It appears that the models given in EN 1992-1-1 and prEN 1992-1-1 lead to more realistic estimates of the reliability level of existing reinforced concrete members with respect to punching shear than the models recommended in some national codes. The controlled perimeter has significant influence on the results and should be harmonized in prescriptive documents.

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24

Pereira, E. V., R. B. Figueira, Manuela M. Salta, and I. T. E. Fonseca. "Embedded Sensors for Corrosion Monitoring of Existing Reinforced Concrete Structures." Materials Science Forum 587-588 (June 2008): 677–81. http://dx.doi.org/10.4028/www.scientific.net/msf.587-588.677.

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In this work the performance of two surface treatments and the efficiency of a corrosion inhibitor were evaluated, in the control of steel corrosion in concrete induced by chlorides, through measurements of galvanic current and polarization resistance applied to embedded sensors fixed in existing concrete using different methodologies. From the results obtained the use of the different embedded sensors in the measurement of corrosion rate is discussed aiming the development of new systems for permanent evaluation of the on site performance of products for repairing reinforced concrete structures affected by reinforcement corrosion.

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25

Inukai, M. "Reuse of Reinforced Concrete Foundation Piles in Existing Buildings." Concrete Journal 41, no. 11 (2003): 3–8. http://dx.doi.org/10.3151/coj1975.41.11_3.

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26

Koteš, Peter, and Josef Vičan. "Remaining Lifetime of Existing Reinforced Concrete and Steel Bridges." IABSE Symposium Report 92, no. 15 (January 1, 2006): 10–17. http://dx.doi.org/10.2749/222137806796169830.

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CROWLEY, H., and R. PINHO. "PERIOD-HEIGHT RELATIONSHIP FOR EXISTING EUROPEAN REINFORCED CONCRETE BUILDINGS." Journal of Earthquake Engineering 8, sup001 (January 2004): 93–119. http://dx.doi.org/10.1080/13632460409350522.

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Priestley, M. J. N. "Displacement-based seismic assessment of existing reinforced concrete buildings." Bulletin of the New Zealand Society for Earthquake Engineering 29, no. 4 (December 31, 1996): 256–72. http://dx.doi.org/10.5459/bnzsee.29.4.256-272.

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Seismic assessment of existing reinforced concrete frame and shear wall buildings is discussed. Building on an earlier preliminary assessment procedure incorporating aspects of capacity design into a systems approach for assessment, suggestions are made towards a displacement-based, rather than forced-based approach to determining available capacity. Based on results from recent experimental programs, procedures are proposed for assessing member strength including column and beam-column joint shear strength, that result in less conservative estimates of performance than would result from application of existing code rules.

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Liang, Ming-Te, Jai-He Wu, and Chih-Hsin Liang. "Multiple Layer Fuzzy Evaluation for Existing Reinforced Concrete Bridges." Journal of Infrastructure Systems 7, no. 4 (December 2001): 144–59. http://dx.doi.org/10.1061/(asce)1076-0342(2001)7:4(144).

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Oey, Hong Sioe, and Carlos J. Aldrete. "Simple Method for Upgrading an Existing Reinforced-Concrete Structure." Practice Periodical on Structural Design and Construction 1, no. 1 (February 1996): 47–50. http://dx.doi.org/10.1061/(asce)1084-0680(1996)1:1(47).

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Hajiesmaeili, Amir, Francesco Pittau, Emmanuel Denarié, and Guillaume Habert. "Life Cycle Analysis of Strengthening Existing RC Structures with R-PE-UHPFRC." Sustainability 11, no. 24 (December 5, 2019): 6923. http://dx.doi.org/10.3390/su11246923.

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(PE)-UHPFRC, a novel strain hardening ultra high-performance fiber reinforced concrete (UHPFRC) with low clinker content, using Ultra-High Molecular Weight Polyethylene (UHMW-PE) fibers, was developed for structural applications of rehabilitation. A comprehensive life cycle assessment (LCA) was carried out to study the environmental impact of interventions on an existing bridge using PE-UHPFRC compared with conventional UHPFRC and post-tensioned reinforced concrete methods in three categories of global warming potential (GWP), cumulative energy demand (CED), and ecological scarcity (UBP). The results showed 55% and 29% decreases in the environmental impact of the PE-UHPFRC compared with reinforced concrete and conventional UHPFRC methods, respectively, which highlighted the effectiveness of this material for the rehabilitation/strengthening of structures from the viewpoint of environmental impact.

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Zhang, Bing, Jun-Liang Zhao, Tao Huang, Ning-Yuan Zhang, Yi-Jie Zhang, and Xia-Min Hu. "Effect of fiber angles on hybrid fiber-reinforced polymer–concrete–steel double-skin tubular columns under monotonic axial compression." Advances in Structural Engineering 23, no. 7 (January 2, 2020): 1487–504. http://dx.doi.org/10.1177/1369433219895916.

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Hybrid fiber-reinforced polymer–concrete–steel double-skin tubular columns are a novel form of hollow columns that combine two traditional construction materials (i.e. concrete and steel) with fiber-reinforced polymer composites. Hybrid fiber-reinforced polymer–concrete–steel double-skin tubular columns consist of an inner tube made of steel, an outer tube made of fiber-reinforced polymer, and a concrete layer between the two tubes. Existing studies, however, are focused on hybrid fiber-reinforced polymer–concrete–steel double-skin tubular columns with fibers of the fiber-reinforced polymer tube oriented in the hoop direction or close to the hoop direction. In order to investigate the effect of fiber angles (i.e. the fiber angle between the fiber orientation and the longitudinal axis of the fiber-reinforced polymer tube), monotonic axial compression tests were conducted on hybrid fiber-reinforced polymer–concrete–steel double-skin tubular columns with an fiber-reinforced polymer tube of ±45°, ±60°, or ±80° fiber angles. There were two types of steel tubes adopted for these hybrid fiber-reinforced polymer–concrete–steel double-skin tubular columns. The fiber-reinforced polymer tube thickness was also investigated as an important parameter. Experimental results showed that the confinement effect of the fiber-reinforced polymer tube increased with the increase of the absolute value of fiber angles, whereas the ultimate axial strain of hybrid fiber-reinforced polymer–concrete–steel double-skin tubular columns decreased with the increase of the absolute value of fiber angles. An existing stress–strain model, which was developed on the basis of hybrid fiber-reinforced polymer–concrete–steel double-skin tubular columns with an fiber-reinforced polymer tube of ±90° fiber angles, is verified using the test results of this study. For the compressive strength of the confined concrete in hybrid fiber-reinforced polymer–concrete–steel double-skin tubular columns, the existing model provides conservative predictions for specimens with a ±80° fiber-reinforced polymer tube, overestimated predictions for specimens with a ±60° fiber-reinforced polymer tube, and close predictions for specimens with a ±45° fiber-reinforced polymer tube.

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MURASHKIN, V. G. "SECANT MODULUS RATIO FOR RECONSTRUCTABLE REINFORCED CONCRETE." Building and reconstruction 104, no. 6 (2022): 50–55. http://dx.doi.org/10.33979/2073-7416-2022-104-6-50-55.

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During the reconstruction, or upon expiration of the service life, as well as after external impact, reinforced concrete structures require examination and verification calculations. The most modern and accurate calculations are based on diagram methods. Existing diagrams of concrete deformation are focused on designing new structures and are not adapted to the concretes that have changed their strength and deformation properties over time or because of external influences. The main parameter describing the deformability of concrete is the secant modulus ratio. A technique for determining the secant modulus ratio is proposed in this arctical. The technique is based on using the exponential concrete deformation model. The obtained secant modulus ratio can be used for the widely adopted description of the concrete deformation diagram. The technique is illustrated on a specific example. The proposed technique significantly expands the application range of diagram methods and extend them to concrete after long-term operation or external impact.

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Su, Min Fang, and Hong Guo. "Energy-Saving Renovation in Existing High-Rise Residential Building." Applied Mechanics and Materials 409-410 (September 2013): 526–30. http://dx.doi.org/10.4028/www.scientific.net/amm.409-410.526.

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Based on the structure feature and energy consumption situation of high-rise reinforced concrete residential buildings which built in end of last century, it discussed the main energy-saving renovation technologies and methods. Demonstrating high-rise reinforced concrete residential building of Taiyuan as a case, it analyzed its heat loss problems and defects of original design. Energy-saving renovation plan proposed and put reconstruction technologies of building envelope and heating system in practice. It discusses energy-saving renovation effects, energy efficiency. Indoor thermal environment improved significantly after energy-saving renovation on building envelope and heat system.

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Qian, Hui, Qingyuan Zhang, Xun Zhang, Enfeng Deng, and Jundong Gao. "Experimental Investigation on Bending Behavior of Existing RC Beam Retrofitted with SMA-ECC Composites Materials." Materials 15, no. 1 (December 21, 2021): 12. http://dx.doi.org/10.3390/ma15010012.

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In order to realize the self-centering, high energy consumption, and high ductility of the existing building structure through strengthening and retrofit of structure, a method of reinforced concrete (RC) beam strengthened by using Shape Memory Alloy (SMA) and Engineered Cementitious Composites (ECC) was proposed. Four kinds of specimens were designed, including one beam strengthened with enlarging section area of steel reinforced concrete, one beam strengthened with enlarging section area of SMA reinforced concrete, beam strengthened with enlarging section area of SMA reinforced ECC, and beam strengthened with enlarging section area of steel reinforced ECC; these specimens were manufactured for the monotonic cycle loading tests study on its bending behavior. The influence on the bearing capacity, energy dissipation performance, and self-recovery capacity for each test specimens with different strengthening materials were investigated, especially the bending behavior of the beams strengthened by SMA reinforced ECC. The results show that, compared with the ordinary reinforced concrete beams, strengthening existing RC beam with enlarging section area of SMA reinforced ECC can improve the self-recovery capacity, ductility, and deformability of the specimens. Finally, a revised design formula for the bending capacity of RC beams, strengthened with enlarging sections of ECC, was proposed by considering the tensile capacity provided by ECC, and the calculated values are in good agreement with the experimental value, indicating that the revised formula can be well applied to the beam strengthening with enlarging section of SMA-ECC Materials.

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Li, Weiwen, Chengyue Hu, Zejie Pan, Wei Peng, Yong Yang, and Feng Xing. "A proposed strengthening model considering interaction of concrete-stirrup-FRP system for RC beams shear-strengthened with EB-FRP sheets." Journal of Reinforced Plastics and Composites 37, no. 10 (March 23, 2018): 685–700. http://dx.doi.org/10.1177/0731684418760204.

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Many factors can affect the shear capacity of fiber-reinforced polymer in reinforced concrete beams shear-strengthened with externally bonded fiber-reinforced polymer composites. Undoubtedly, the interaction of concrete-stirrup-fiber-reinforced polymer system is one of the key factors. However, most of the existing fiber-reinforced polymer design guidelines do not take account of this important factor on predicting fiber-reinforced polymer shear capacity. This study provides an advanced strengthening model that comprehensively considers the interaction among concrete, stirrup, and fiber-reinforced polymer for calculating the fiber-reinforced polymer effective strain. The advanced strengthening model provides a more accurate prediction for the fiber-reinforced polymer shear contribution compared with existing design guidelines.

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Timchenko, R. A., D. A. Krishko, and S. О. Macyshin. "CONSTRUCTIVE SOLUTION OF A TUNNEL UNDER THE EXISTING HIGHWAY." ACADEMIC JOURNAL Series: Industrial Machine Building, Civil Engineering 2, no. 49 (October 17, 2017): 214–20. http://dx.doi.org/10.26906/znp.2017.49.845.

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Urban underground structures (shallow tunnels), which are usually built in conditions of urban area with heavy traffic, are considered. It was clarified that the reinforced concrete lining are performed of concrete, reinforced concrete, natural and artificial stones in most cases. The types of tunnels road cutting are given. The geometrical dimensions and characteristics of using materials in the construction of tunnels are given. It was established that the existing methods of tunnel construction do not allow to solve the problem in cramped conditions and intense traffic. The new constructive solution of the transverse tunnel under the existing highway was proposed. It is found that the proposed design of the transverse tunnel may be performed in cramped urban environments with the use of modern technological equipment and the proposed method of tunnel meets the requirements of strength, reliability, durability.

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Agunov, Alexander V., Ilya A. Terekhin, and Ivan A. Baranov. "Analysis of the application of electric conducting concrete in the power industry." Transportation Systems and Technology 7, no. 2 (July 1, 2021): 5–15. http://dx.doi.org/10.17816/transsyst2021725-15.

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At present, on the territory of the Russian Federation, there is no massive use of electrically conductive reinforced concrete structures in the electric power industry due to insufficient operating experience and a low rate of research on electrically conductive concretes. The article compares the main characteristics of existing electrically conductive concrete. The paper shows the disadvantages of traditional concrete and existing electrically conductive concrete. The electrically conductive concrete was selected, the most suitable for further research, testing and direct modernization of the composition based on the results obtained. The main disadvantages of existing electrically conductive concretes are the high cost and specificity of electrically conductive components and other additives, as a consequence of the amount of capital investment in mass and large-scale production, as well as the lack of operating experience as overhead supports.

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Cheng, Shanshan. "Mechanical Behavior of Fiber-to-concrete Interface in Textile Reinforced Concrete: Theoretical Model." Journal of Civil Engineering and Construction 8, no. 2 (May 15, 2019): 70–78. http://dx.doi.org/10.32732/jcec.2019.8.2.70.

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This paper presents a theoretical solution of a reinforcement-to-concrete interface model under pull-push loading. Expressions for the interfacial shear stress distribution and load-displacement history are derived for different loading stages. The full debonding propagation process is discussed in detail and the analytical solutions are verified by comparing with existing theoretical models. Results of the analytical solution are presented to illustrate how the bond length and local bond-slip law affect the interfacial bond behavior. While the case study in this paper is on textile reinforced concrete, the analytical solution is equally valid to similar mechanical cases such as rebar reinforced concretes.

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Lukashevich, Viktor, Igor Efanov, Viktor Vlasov, and Olga Lukashevich. "Asphalt concrete pavement reinforced with chemical fibers." MATEC Web of Conferences 216 (2018): 01013. http://dx.doi.org/10.1051/matecconf/201821601013.

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Asphalt concrete pavement which is currently built in accordance with the existing requirements does not withstand the standard service life. Various kinds of damages occur. Fiber reinforcement of asphalt concretes is one of the effective means to deal with deformations and fractures of road pavements, such as rutting, buckling, crack formation and shear. Chemical fibers serving as reinforcement are of great concern herein. The major purpose of this work was evaluation of reinforcement fibers resistance to natural environment and climatic impacts within the conditions of experimental production construction and studying compactibility of asphalt concrete mixture with fiber reinforcement. Infrared spectroscopy and physical-chemical investigations of fibers were used to study changing properties of fiber-forming polymer. Compactibility of asphalt concrete mixture with fiber reinforcement was determined upon compaction factor. Research results revealed insignificant influence of natural environment and climatic impacts on the properties of fiber reinforcement material. In order to obtain the standard compaction factor of asphalt concrete additional compacting impact is not required.

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RYAZANOVA, Galina N., and Daria M. POPOVA. "ANALYSIS OF EXISTING METHODS OF CONSTRUCTION FROM MONOLITHIC CONCRETE AND REINFORCED CONCRETE IN WINTER CONDITIONS." Urban construction and architecture 8, no. 1 (March 15, 2018): 16–23. http://dx.doi.org/10.17673/vestnik.2018.01.3.

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The advantages of monolithic concrete and reinforced concrete in comparison with traditional technologies are considered. The evaluation of the structure of construction technology is given. The analysis of the main methods of winter concreting with the development of the structure of heating and non-heating methods is given. The main methods of maintaining concrete and reinforced concrete at negative ambient temperatures are described. An algorithm for estimating the methods of winter concreting for technical and economic indicators is developed: labor costs and electricity consumption. Prospects for the development taking into account the technical and economic eff ectiveness of the option of combining non-heating and heating methods for further investigation are outlined.

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Utkin, Vladimir S., and Leonid A. Sushev. "THE RELIABILITY ANALYSIS OF EXISTING REINFORCED CONCRETE PILES IN PERMAFROST REGIONS." International Journal for Computational Civil and Structural Engineering 13, no. 2 (June 30, 2017): 64–72. http://dx.doi.org/10.22337/2587-9618-2017-13-2-64-72.

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The article describes the general problem of safe operation of buildings and structures with the dynamics of permafrost in Russia and other countries. The global warming on Earth will lead to global disasters such as failures of buildings and structures. The main reason of these failures will be a reduction of bearing capacity and the reliability of foundations. It is necessary to organize the observations (monitoring) for the process of reducing the bearing capacity of foundations to prevent such accidents and reduce negative consequences, to development of preventive measures and operational methods for the piles reliability analysis. The main load-bearing elements of the foundation are reinforced concrete piles and frozen ground. Reinforced concrete piles have a tendency to decrease the bearing capacity and reliability of the upper (aerial) part and the part in the soil. The article discusses the problem of reliability analysis of existing reinforced concrete piles in upper part in permafrost regions by the reason of pile degradation in the contact zone of seasonal thawing and freezing soil. The evaluation of the probability of failure is important in itself, but also it important for the reliability of foundation: consisting of piles and frozen soil. Authors offers the methods for reliability analysis of upper part of reinforced concrete piles in the contact zone with seasonally thawed soil under different number of random variables (fuzzy variables) in the design mathematical model of a limit state by the strength criterion.

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Kara, Ilker, and Besian Sinani. "Prediction of Punching Shear Capacity of Two-Ways FRP Reinforced Concrete Slabs." Spring 2017 5, no. 2 (May 1, 2017): 1–7. http://dx.doi.org/10.33107/ijbte.2017.5.2.03.

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An innovative solution to the corrosion problem is the use of fiber-reinforced polymer (FRP) as an alternative reinforcing material in concrete structures. In addition to the non corrodible nature of FRP materials, they also have a high strength-to-weight ratio that makes them attractive as reinforcement for concrete structures. Extensive research programs have been carried out to investigate the flexural behavior of concrete members reinforced with FRP reinforcement. On the other hand, the shear behavior of concrete members, especially punching shear of two-way slabs, reinforced with FRP bars has not yet been fully explored. The existing provisions for punching of slabs in most international design standards for reinforced concrete are based on tests of steel reinforced slabs. The elastic stiffness and bonding characteristics of FRP reinforcement are sufficiently different from those of steel to affect punching strength. In the present study, the equations of existing design standards for shear capacity of FRP reinforced concrete beams have been evaluated using the large database collected. The experimental punching shear strengths were compared with the available theoretical predictions, including the CSA S806 (CSA 2012), ACI-440.1R-15 (ACI 2015), BS 8110 (BSI 1997), JSCE (1997) a number of models proposed by some researchers in the literature. The existing design methods for FRP reinforced concrete slabs give conservative predictions for the specimens in the database. This paper also presents a simple yet improved model to calculate the punching shear capacity of FRPreinforced concrete slabs. The proposed model provides the accurate results in calculating the punching shear strengths of FRP-reinforced concrete slender slabs.

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KITAGO, Yukio, and Toyoaki MIYAGAWA. "Carbonation of Concrete and Corrosion of Steel Bars in Existing Reinforced Concrete Structures." Journal of the Society of Materials Science, Japan 49, no. 4 (2000): 413–19. http://dx.doi.org/10.2472/jsms.49.413.

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KJU KJU NWE, Kazushi SADASUE, and Hideo ARAKI. "ULTIMATE SHEAR STRENGTH OF EXISTING STEEL REINFORCED CONCRETE MEMBERS WITH LOW-STRENGTH CONCRETE." Journal of Structural and Construction Engineering (Transactions of AIJ) 84, no. 761 (2019): 983–92. http://dx.doi.org/10.3130/aijs.84.983.

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Ma, Li Jun. "Research on Bridge Seismic Performance of Reinforced Concrete Reinforced by Carbon Fiber." Advanced Materials Research 1055 (November 2014): 15–18. http://dx.doi.org/10.4028/www.scientific.net/amr.1055.15.

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With the increase of urban construction, appraising and reinforcing the existing architectures is increasingly attracting people’s attention. As a high-strength light material, more and more carbon fiber materials are applied to reinforce architecture. Using carbon fiber sheet to strengthen reinforced concrete frame structure not only can effectively improve the ultimate load-carrying capacity and energy dissipation capacity, but also can maintain the later stiffness and stability. And the reinforcement effect of carbon fiber is more evident.

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Wagner, Juliane, Carolin Würgau, Alexander Schumann, Elisabeth Schütze, Daniel Ehlig, Lutz Nietner, and Manfred Curbach. "Strengthening of Reinforced Concrete Structures with Carbon Reinforced Concrete—Possibilities and Challenges." CivilEng 3, no. 2 (May 13, 2022): 400–426. http://dx.doi.org/10.3390/civileng3020024.

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The strengthening of existing reinforced concrete structures (RC) with carbon reinforced concrete (CRC) has a high potential to save resources and to increase the lifespan of the whole strengthened structure immensely. However, when strengthening structures with CRC, in some cases, failure due to concrete cover separation is detected, leading to the fact that the potential of the carbon reinforcement cannot be exploited. The prediction and prevention of this type of failure is the subject of current research. In this paper, a strut-and-tie-model is presented for calculating a critical tensile force leading to failure due to concrete cover separation. Additionally, possible methods to avoid that kind of failure are suggested. One of these is doweling the ends of the strengthening layer. This paper presents the first experiments to test this method, which show that doweling the strengthening layer leads to much higher failure loads compared to a structure without doweling. However, further investigations have to be examined to verify these first results.

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Zhou, Guang Qiang, and Feng Min Xia. "Study on Moment-Curvature Hysteresis Relationship of Reinforced Concrete Shear Walls." Applied Mechanics and Materials 166-169 (May 2012): 3110–13. http://dx.doi.org/10.4028/www.scientific.net/amm.166-169.3110.

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In order to study and improve moment-curvature hysteresis model of reinforced concrete shear walls, experiment of reinforced concrete shear walls was conducted. Based on experiment of reinforced concrete shear walls, moment-curvature relationship is deduced and moment-curvature hysteresis curves are obtained. The existing moment-curvature hysteresis models of reinforced concrete walls are discussed and improved, and the calculated moment-curvature hysteresis curves with the modified model fit well with experimental results.

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Jebelean, Eugen, Catalin Badea, Liana Iures, Cornel Jiva, and Ioan Borza. "Acoustical Methods Used in the Study of Concrete Durability." Applied Mechanics and Materials 430 (September 2013): 113–17. http://dx.doi.org/10.4028/www.scientific.net/amm.430.113.

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The paper presents the experimental research on concretes and in-situ research on existing reinforced concretes elements, using “Pulse Velocity Method”. The “Pulse Velocity Method” it is an acoustical method which uses the ultra-sounds with 20 to 200 kHz frequency. The in-situ acoustic results are used to establish the durability of the concrete in the tested elements.

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Lahdensivu, Jukka, Elina Lahdensivu, and Arto Köliö. "Case Study on the 20 Years Propagation of Carbonation in Existing Concrete Facades and Balconies." Nordic Concrete Research 60, no. 1 (June 1, 2019): 1–12. http://dx.doi.org/10.2478/ncr-2019-0004.

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Abstract In the most service life models of reinforced concrete structures the initiation phase is the most crucial, because according to models, service life of the structure will end underestimation on conservative side when carbonation achieves the reinforcement for the first time. The square root model is widely used in predicting carbonation depth of reinforced concrete. The model is based on diffusion laws and thereby arguable for inhomogeneous concrete. The model was evaluated by field measurements from one existing concrete building by conducting condition investigation twice at a time interval of 20 years. Samples were taken from exposed aggregate concrete sandwich panels and balcony side panels. Compared to the data collected from large number of buildings, the measured carbonation rates were very common for Finnish concrete buildings made during the 1960s and 1970s. According to this study, in solid concrete the progress of carbonation of concrete can be predicted reliably with Fick’s second law. This model, however, gives too pessimistic predictions for concrete suffering from freeze-thaw damage. Therefore, a new model has been presented for damaged concrete.

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Journal articles on the topic 'Existing Reinforced Concrete'

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