Journal articles: 'Hollow concrete slab'

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Renkas, A. A. "FIRE RESISTANCE PROVIDING OF HOLLOW‐CORE CONCRETE SLABS USING SHEET BUILDING MATERIALS." Fire Safety, no. 34 (July 19, 2019): 72–77. http://dx.doi.org/10.32447/20786662.34.2019.12.

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Introduction. This paper deals with the analysis of world experience in fire resistance providing of hollow‐core concrete slabs. To protect concrete structures are used many structural applications: thermal coatings and materials. The research first analyzes main methods and hypothesis using to make temperature analysis of solution fire resistance of concrete structures. Problem of making temperature analysis of hollow‐core concrete slabs are nonlinear thermal material properties and radiation heat transfer in the hollow-cores. The aim of this paper is to establish the temperature distribution in hollow‐core concrete slab considering radiation heat transfer in the hollow-cores in case of fire in compartment that is spreading by standard temperature-time curve. In addition, the aim is to substantiate the possibility of using gypsum panels to provide fire resistance of hollowcore concrete slabs. Material statement. The paper reports the results of modeling the process of heat transfer in hollow‐core concrete slab, between compartment space and slab surface and in hollow‐cores. To calculate temperature fields in hollow‐core concrete slab considering nonlinear thermal material properties and radiation heat transfer in the hollow-cores was used finite element model. At addition, the results of finite elements simulations show temperature fields in hollow‐core concrete slab and gypsum panels that installed under concrete slab. Scientific novelty. The paper reports results of theoretic substantiated of possibility of using gypsum panels to protect of hollow‐core concrete slabs considering nonlinear thermal material properties, radiation heat transfer between surfaces and radiation heat transfer in the hollow-cores. The results indicate that using gypsum panels to protect of hollow‐core concrete slabs reduces speed heating of concrete elements to critical temperatures that increase fire resistance of hollow‐core concrete slabs to 20.4 %.

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Valivonis, Juozas, Bronius Jonaitis, Robertas Zavalis, Tomas Skuturna, and Arnoldas Šneideris. "FLEXURAL CAPACITY AND STIFFNESS OF MONOLITHIC BIAXIAL HOLLOW SLABS." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 20, no. 5 (October 20, 2014): 693–701. http://dx.doi.org/10.3846/13923730.2014.917122.

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The article presents a research on flexural behaviour of hollow monolithic reinforced concrete slabs. It focuses on the results of experimental investigation into full-size hollow reinforced concrete slabs and analyses their flexural capacity and stiffness. The self-weight of the slabs directly depends on the shape and number of hollows. An increase in the hollowness of a slab significantly reduces the load caused by self-weight. This allows increasing the estimated length of the slab under the same payload. An increase in the amount of hollows of the slab changes the stiffness of the slab cross-section that has a direct impact on slab deflection. Considering the shape of the slab cross-section, theoretical calculations of the flexural capacity and deflection of experimental slabs were made. The design of a new type of slabs and variations in different parameters of the slab experience difficulties in conducting a large amount of experimental tests. Therefore, the initial analysis may apply to numerical simulation. The paper describes the principles of designing a numerical model. The calculations were made using DIANA software. The stiffness and flexural capacity of the hollow slabs were established employing numerical simulation compared to the results of experimental investigations. The findings indicate that numerical simulation can be applied for analysing the stress state of the examined structures.

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Surianinov, Mykola, Stepan Neutov, Iryna Korneieva, and Maryna Sydorchuk. "Study and Comparison of Characteristics of Models of Hollow-Core Slabs, Reinforced Concrete and Steel-Fiber Concrete." Key Engineering Materials 864 (September 2020): 9–18. http://dx.doi.org/10.4028/www.scientific.net/kem.864.9.

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Two models of hollow core slabs were tested: reinforced concrete and steel fiber concrete. When designing slab models, the proportions of full-sized structures were preserved for the further possibility of correct data comparison. As a result of testing models of hollow core slabs, it was found that the bearing capacity of a slab with combined reinforcement is 24% higher than that of reinforced concrete, the deflection is 36% less, and the crack resistance is 18% higher. The use of steel fiber made it possible to avoid the brittle fracture of a steel fiber reinforced concrete slab, which was observed in the model of a conventional reinforced concrete slab.

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Zhao, Xin, Dan Dan Kong, Zhi Wei Zhang, and Mai Wu. "Study on Mechanical Behaviors of New Reinforced Concrete Hollow Floor Slab." Applied Mechanics and Materials 94-96 (September 2011): 1018–21. http://dx.doi.org/10.4028/www.scientific.net/amm.94-96.1018.

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In this paper a new type of reinforced concrete four-way rib hollow slab was proposed by the authors first. Further in order to research on the mechanical properties of the new floor slab the other two common slabs were compared with the new one, that was two-way rib hollow slab and solid slab. The rational finite element (FE) models of the three kinds of slabs supported by four corner columns were built up respectively by ANSYS. The deflection and stress of the three kinds of slabs under three load cases were calculated separately, on the basis of which thorough comparisons and analysis were carried out. The study results showed that the new reinforced concrete four-way rib hollow floor slab has superior mechanical properties.

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Nassif Sabr, Yousif, Dr Husain Khalaf Jarallah, and Dr Hassan Issa Abdul Kareem. "Improving the Shear Strength of Lightweight RC Thick Hollow Core Slab Made of Recycled Materials." International Journal of Engineering & Technology 7, no. 4.20 (November 28, 2018): 403. http://dx.doi.org/10.14419/ijet.v7i4.20.26143.

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This research paper focused on the experimental study about shear behavior of reinforced concrete thick hollow core slab. The reduction hollow length technique was used to resist the shear failure that occurred in the thick hollow core slab. The three hollows were used in tested slabs. The effect of reduction in the length of hollow in the shear region as well as the sides hollow was considered in the shear behavior of the tested hollow core slab. The recyclable material was used to a get of lightweight concrete, where the crushed clay brick was used as a coarse aggregate instead of the gravel. The test was done by applying two line load. The specimens were tested up to failure. The experimental results showed an increase in the shear strength up to 109.52% and an increase in the deflection up to 24% compared with the hollow core slab specimen that all hollow core is accessible. From the experimental result of this investigation can avoid the shear failure subsequently the load devolves from the shear region to the flexural region with change the mode of failure from shear failure to flexural-shear failure.

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Yang, Xiao Hua, and Cao Yang Zhou. "Simplified Calculation Method for Deflection of Concrete Cellular Slab." Advanced Materials Research 1049-1050 (October 2014): 196–200. http://dx.doi.org/10.4028/www.scientific.net/amr.1049-1050.196.

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The continuity of concrete cellular slab was damaged by tubular hollow tubes which are arranged in slabs in parallel and the mechanical properties of slab exists anisotropy leading by different shapes of cross section in both directions of parallel and vertical to hollow tubes. Slab stiffness is weak greatly in direction of parallel to hollow tubes. For concrete cellular slab, the mechanical and deformation properties have been studied, the rigidity and stiffness ratio formula in both directions are been given. Orthotropic slab analogue method that is simplified calculation method for slab deflections are put out. The calculated results show that this method is adaptable and processes are simple. The calculated results are close to with engineering practices.

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7

Yang, Xiao Hua, Chao Yang Zhou, Xue Jun He, and Teng Chen. "Research on Post-Tensioned Unbonded Prestressed Concrete Hollowed Floor." Applied Mechanics and Materials 94-96 (September 2011): 1456–62. http://dx.doi.org/10.4028/www.scientific.net/amm.94-96.1456.

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In order to study the mechanical behaviors of post-tensioned unbonded prestressed concrete hollowed floors, a 1/4 scale post-tensioned unbonded prestressed reinforced concrete hollow slab-column structure model is used to act uniform distributed load on the floor. The test results showed that the load carrying capacity is enough. The points of maximum displacement are at the centers of slabs. By means of the experimental studies and elastic finite element analysis methods, the results showed that post-tensioned unbonded prestressed concrete hollowed floor presents anisotropy with layout of circular-tubes in one way. In direction parallel to layout of hollowed tubes, the continuity of floor is destruction and bending stiffness of slab is weakened. For studying the deformations of slab, it can still be considered continuous cross-slab in two directions.

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8

Zhang, Jing Shu, Huan Huan Nie, Yuan Long Yang, and Yuan Yao. "Research and Application of Pre-Stressed Concrete Composite Slabs." Applied Mechanics and Materials 166-169 (May 2012): 131–39. http://dx.doi.org/10.4028/www.scientific.net/amm.166-169.131.

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The pre-stressed concrete composite slab, which combines the advantages of cast-in-place slabs and precast slabs, has promising development prospects. In the paper, according to structural integrity, bond performance, sound insulation, thermal preservation and construction techniques, four categories composite slab, such as the composite slab with flat bottom panel (including the composite slab with bar truss reinforced precast concrete bottom panel), the concrete composite slab with precast ribbed panel, the composite slab with hollow bottom panel and the composite slab with sandwich bottom panel are studied. The composite slab with flat bottom panel has poor structural integrity, and its bond performance and crack resistance of edge joint details need to be improved; the composite slab with bar truss reinforced precast concrete bottom panel has enough bond force, but its storage and transportation are inconvenient; the concrete composite slab with precast ribbed panel has good structural integrity and convenient construction procedure; the composite slab with hollow bottom panel and the composite slab with sandwich bottom panel have functions of sound insulation and thermal preservation, however they are inadequacy to resist bending moment and have complex construction procedure. The concrete composite slab with precast ribbed panel is provided with good mechanical behavior, economy and practicability, and is worth further researching and promoting.

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9

Li, Shiping, and Chao Song. "Mechanical performance test and analysis of prestressed lightweight aggregate concrete hollow slab." Advances in Structural Engineering 22, no. 8 (February 3, 2019): 1830–44. http://dx.doi.org/10.1177/1369433219825998.

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To investigate the mechanical performance of prestressed lightweight aggregate concrete hollow slabs, a symmetric loading test was performed on eight prestressed concrete hollow slabs categorised into four groups based on their variety of coarse aggregate concrete and span, and their respective failure mode, bearing capacity, deformation performance and crack propagation were analysed. Based on the test data, a simulation model was subsequently established to simulate and analyse the test components. The test results showed that the bending process of the prestressed lightweight aggregate concrete hollow slab goes through three stages: elasticity, elasto-plasticity and plasticity. Furthermore, its bearing capacity and failure characteristics are similar to those of a prestressed ordinary concrete hollow slab. Subsequently, we derived a formula for checking the calculation of crack width by introducing a comprehensive influence coefficient of concrete Cm and combining it effectively with the formula in the current code and verified its efficacy. The calculated value of the formula agrees well with the test results, providing a reference for the application of engineering and a supplementary calculation formula for the crack width of lightweight aggregate concrete hollow slabs.

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10

Jendzelovsky, Norbert, and Kristina Zabakova Vrablova. "Comparison of Natural Frequencies of Hollow Core Slabs." Applied Mechanics and Materials 769 (June 2015): 225–28. http://dx.doi.org/10.4028/www.scientific.net/amm.769.225.

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This article is devoted to the calculation of natural frequencies of concrete slabs. Natural frequencies of a solid slab and a hollow core slab have been compared. Solid slab and lightened slab with reduced self-weight and stiffness have been modeled using FEM software ANSYS as 2D model using shell elements. Third model was made from 3D elements as a hollow core slab. Two types of boundary conditions have been considered: a simply supported slab and a clamped slab. The changes in natural frequencies according to aspect ratio of the slab were compared, too. Numerical methods have been compared with simplified method of calculation of natural frequency of slabs, as e.g. an equivalent plate approach; approximation presented by Hearmon and compilation of formulas by Bachmann.

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11

Dulinskas, Eugenijus, Andrej Jarmolajev, Vidmantas Jokūbaitis, Gintaras Jurkenas, Lolita Kairyte, Gintaras Šaučiuvenas, Arnoldas Šneideris, and Povilas Vainiūnas. "THE DAMAGES OF BEARING CONSTRUCTION IN NOT CONSERVED BUILDINGS AND THE RESEARCH INTO THEIR SUITABILITY FOR FUTURE EXPLOATATION." Technological and Economic Development of Economy 10, no. 3 (September 30, 2004): 96–101. http://dx.doi.org/10.3846/13928619.2004.9637664.

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There are frequent cases when load‐bearing reinforced concrete structures of not completed buildings are directly exposed to precipitation (rainfall, snowfall) and to environment of positive and negative temperature. Multihollowcore concrete slabs are especially vulnerable to such actions since investigations of condition of non‐conserved buildings indicate that these slabs can crack critically. Water accumulated in hollows of slabs and frozen under negative temperature can split concrete in vertical walls between hollows, inflict concrete cracking below hollows or spalling of large sections together with longitudinal reinforcement in them at the bottom of slabs. In performed investigations of condition of non‐completed and non‐conserved load bearing structures a modern method was employed for the determination of cracking in walls between hollows of slabs, using mini video‐camera. Analysis of cracking in slabs indicated that the character of cracking is governed by the quantity of water accumulated in a hollow at the moment of freezing and the level of freezing water in adjacent hollows of a slab and the compaction quality of concrete in a tensile zone of a slab as well. The analysis of pressure on the surface of hollows developed by ice set can be analysed employing a model of non‐linear analysis of COSMOS/M program and fracture mechanics of solids. Several versions of cracking in multihollowcore concrete slabs are possible, the most critical one of which is when a part of a bottom flange of a slab together with longitudinal reinforcement spalls off due to normal and shear deformations. The accomplished analysis allowed to establish kinetics of cracking for slabs and to evaluate their condition more reliably.

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12

Han, Juan, and Yin Liang. "Experimental Study on Flexural Behavior of Different Damages Prestressed Concrete Hollow Slabs Strengthened with CFRP." Applied Mechanics and Materials 351-352 (August 2013): 592–95. http://dx.doi.org/10.4028/www.scientific.net/amm.351-352.592.

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The purpose of this paper is to focus on studying its flexural behavior after different damages prestressed concrete hollow slab is strengthened with CFRP.By the experimental method, twelve residential prestressed concrete hollow slabs are tested under concentrated force at the two points of the symmetrical load in order to analyze both flexural behavior and effects factored by different bonding modes.The conclusion can be drawn that the flexural behavior of prestressed concrete hollow slabs strengthened with CFRP is well-tried.It provides design suggestions and reference for prestressed concrete hollow slabs strengthened with CFRP, and also provides an experimental basis for the repairing and reinforcing practical engineering application in Wenchuan disaster area.

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13

Chung, Joo Hong, Hyun Ki Choi, Seung Chang Lee, and Chang Sik Choi. "The Deflection of Donut Type Hollow Slab Considering Crack Behaviors." Key Engineering Materials 577-578 (September 2013): 621–24. http://dx.doi.org/10.4028/www.scientific.net/kem.577-578.621.

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Recently, various types of slab systems which can reduce self-weight of slabs have been studied as the height and width of building structures rapidly increase. A hollow slab system is widely known as one of the effective slab system which can reduce self-weight of slab. According to previous studies, the hollow slab with donut type hollow sphere had enough flexural strength. On the other hand, there were some differences in flexural stiffness and deflection between general RC slab and donut type hollow slab. The deflection of hollow slab was influenced by the shapes of hollow spheres due to its different second moment of inertia and amount of concrete surrounding bottom re-bar. Especially, the cracking behaviors also influence the deflection of slab. General RC slab deflection has been sufficiently investigated and some models to consider the crack behavior such as crack width, crack space, tension stiffening effect, bond-slip relationship. However, there is no study about the crack behavior on the hollow slab. Therefore, the purposes of this paper are to presents the cracking behavior of donut type hollow slab and to evaluate the deflection considering the crack behavior under flexural load.

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14

Jia, Bin, Lei Fu, Yu Zhang, and Yi Lu. "The Study of the Flexural Capacity of Old and New Prestressed Concrete Hollow Slab Strengthened with CFRP." Applied Mechanics and Materials 482 (December 2013): 66–69. http://dx.doi.org/10.4028/www.scientific.net/amm.482.66.

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Prestressed hollow slab strengthened with CFRP is a new reinforcement method. To study the effect on reinforcement through different carbon fiber paste volume and paste manner, we did the experimental study on flexural capacity under the secondary load conditions with prestressed concrete hollow slab commonly used in engineering. Meanwhile, we also did the contrast analysis of reinforcement effect on the old and new prestressed concrete hollow slab. The results showed that prestressed concrete hollow slab strengthened with CFRP could effectively improve the flexural capacity of the specimen, besides the capacity increasing of the old and new prestressed hollow slab is a little difference, but both of the new and old can meet the engineering design specifications.

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15

Wang, Bo, and Juan Han. "Study on Flexural Behavior of Pre-Stressed Concrete Hollow Slabs Strengthen with CFRP." Applied Mechanics and Materials 446-447 (November 2013): 1413–16. http://dx.doi.org/10.4028/www.scientific.net/amm.446-447.1413.

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The purpose of this paper is to focus on studying its flexural behavior after different damages pre-stressed concrete hollow slab is strengthened with CFRP. By the experimental method, twelve residential pre-stressed concrete hollow slabs are tested under concentrated force at the two points of the symmetrical load in order to analyze both flexural behavior and effects factored by different bonding modes. The conclusion can be drawn that the flexural behavior of pre-stressed concrete hollow slabs strengthened with CFRP is well-tried. It provides design suggestions and reference for pre-stressed concrete hollow slabs strengthened with CFRP, and also provides an experimental basis for the repairing and reinforcing practical engineering application in Wenchuan disaster area.

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Zhao, Dong Qi, Yi Jun Tang, Hui Li, Gui Feng Song, and Feng Ling Guan. "The Application Research of Reinforced Concrete Multi-Ribbed Hollow Composite Slab in the Road Slab Culvert." Advanced Materials Research 368-373 (October 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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17

Prakashan, L. V., Jessymol George, Jeena B. Edayadiyil, and Jerin M. George. "Experimental Study on the Flexural Behavior of Hollow Core Concrete Slabs." Applied Mechanics and Materials 857 (November 2016): 107–12. http://dx.doi.org/10.4028/www.scientific.net/amm.857.107.

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Hollow core concrete slabs have many advantages over the conventional solid concrete slabs. The flexural behavior of this type of slabs have not been investigated in detail in the past. The study here addressed this issue by conducting experimental study of four different hollow core concrete slabs along with a solid concrete slab as a control specimen. The load deflection curves were obtained along with the failure load and deflection at the first crack. The effectiveness of the conventional flexural capacity equation in predicting the capacity of hollow core slabs was evaluated. The results from the experimental study were also utilized to do a comparative study among the specimens studied. The study concluded that the conventional flexural strength equation can be used for hollow core slabs too and they have better performance than solid concrete slabs both in terms of load - deflection behavior and serviceability.

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18

Zhao, Qinyan, Zhongyong Zhang, Jiliang Liu, and Mingjin Chu. "Experimental Study on Precast Concrete Shear Walls with Different Hollow Slabs." Open Civil Engineering Journal 8, no. 1 (September 4, 2014): 166–71. http://dx.doi.org/10.2174/1874149501408010166.

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To study mechanical behaviors of shear walls built with precast two-way hollow slabs, two shear walls with different details of hollow slabs were quasi-statically tested under low cyclic loading. The failure mode was analyzed, which vertical macro-cracks appeared on walls due to the details of hollow slabs. Brittle shear failure can be avoided in terms of the failure behaviors evolved from integral wall to the combination of wall and columns. Test results also show that that dimension of transverse holes can affect compressive capacity of the walls when it is larger than that of longitudinal holes in the hollow slab.

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19

Zhang, Rong Lan. "Determination of Minimum Width of Slab Rib between Bores of Tubular Hollow Slab on Cast-in-Place Concrete." Applied Mechanics and Materials 94-96 (September 2011): 153–57. http://dx.doi.org/10.4028/www.scientific.net/amm.94-96.153.

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Shear mechanism of the cross bore slab of tubular hollow slab on cast-in-place concrete is set forth. Shear force and normal stress are calculated for each section of cross bore slab of tubular hollow slab with supported in one-way direction. We can put forward suggestions based on the three conditions. One condition is that shearing stress is no more than shearing resistance on cross bore slab. Another is that tensile stress on rib of cross bore slab is no more than tensile strength of the concrete. The last one is that concrete shearing stress on rib of parallel bore slab is less than its shearing resistant strength. Meanwhile one example is given. So that we can obtain the requirements for minimum rib between bores of tubular hollow slab.

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20

Awad, Yousif Dhari, and Ali Hussein Ali Al-Ahmed. "Performance of Hollow Core Concrete Slab reinforced by embedded steel tubes." Association of Arab Universities Journal of Engineering Sciences 26, no. 4 (December 31, 2019): 17–21. http://dx.doi.org/10.33261/jaaru.2019.26.4.003.

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The aims of this paper are gaining additive knowledge about using steel tubes as reinforcement for hollow-core concrete slabs. For this purpose, this paper presents an investigation of how one-way concrete slabs would behave after embedding steel tubes within the cross section. Five concrete slabs were cast, these specimens differ from one another in the horizontal distance (spacing) between the two steel tubes placed within its cross section, steel tubes positioned in the center of the shorter lane of the specimen (width) which is 400 mm, the steel tubes spaced from each other with 4 different configurations, they were 0, 100, 200 and 300 mm. The ratio of the clear spacing between the two tubes and to the total width of the specimen is indicated (s/b) equal to (0, 0.25, 0.5 and 0.75). In addition to one solid slab cast and tested as a reference for the testing results. All five concrete slabs were loaded up to failure by submitting load at one point at the center of the slab. Only one variable was deemed to be considered and checked on this study which is the (s/b) ratio defined earlier. The results exhibit that, using steel tubes as reinforcement increase the first crack load by 12.75% compared to the reference slab, as well as increasing the ultimate load capacity by 59.02% compared to the reference slab. As for the mid-span deflection, the specimens with steel tubes embedded decreased the deflection values up to 47.37 %.

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21

Jiang, Zi Yue, and Zhao Hui Luo. "Study on Mechanical Behavior Influence of the Hollow Ratio to the Cast-In Situ Concrete Hollow Slab with Two-Way Tube Fillers." Advanced Materials Research 594-597 (November 2012): 942–46. http://dx.doi.org/10.4028/www.scientific.net/amr.594-597.942.

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This paper discribes the problem of cast-in-situ concrete hollow slab with tube fillers allocated by single-way, according to the arrangement principle of tube fillers in the cast-in-situ concrete two-way hollow slab with two-way fillers, using nonlinear finite element analysis method, through the research on mechanical behavior influence of the hollow ratio to hollow slab, and gives the corresponding design recommendations. Lastly, this paper summarizes the layout method of tube fillers and reasonable requst of the hollow ratio for guiding design.

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Jia, Bin, Shao Tie Zhu, and Xiao Liu. "Experimental Study on Flexural Capacity of Prestressed RC Hollow Slabs Strengthened by CFRP." Applied Mechanics and Materials 507 (January 2014): 311–16. http://dx.doi.org/10.4028/www.scientific.net/amm.507.311.

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Based on the experiment of prestressed concrete hollow slab flexural capacity, it obtained CFRP prestressed concrete hollow slab Ultimate bearing capacity, failure mode and load - displacement curve, and analyzed the influence of Mechanical performance and reinforcement effect caused by the paste way and paste amount of CFRP. Based on the test results to determine the most optimal paste way and paste amount of CFRP for the different damage (slight damage, moderate damage and severe damage) prestressed concrete hollow slab to meet their safety requirements.

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Gul, Akhtar, Khan Shahzada, Bashir Alam, Yasir Irfan Badrashi, Sajjad Wali Khan, Fayaz A. Khan, Abid Ali, and Zahid Ur Rehman. "Experimental Study on the Structural Behavior of Cast in-situ Hollow Core Concrete Slabs." Civil Engineering Journal 6, no. 10 (October 1, 2020): 1983–91. http://dx.doi.org/10.28991/cej-2020-03091597.

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An experimental work has been carried out to study the flexural behavior of cast in-situ hollow core reinforced concrete (HCRC) slabs constructed by using easy, cost effective and implementable techniques in field. The precast elements made of different easily available affordable material i.e. concrete, polyvinyl chloride (PVC) and plaster of paris having voided cross- sections of circular, rectangular and triangular shapes were incorporated in one direction during pouring of concrete with minimum flexural reinforcement to construct HCRC slabs. A total of 14 slab specimens including 02 specimens per specification were tested with third point loading for the assessment of flexural behavior as per ASTM standards C78/C78M. The flexural behavior of HCRC slabs with polyvinyl and plaster of paris elements having hollow cross-sections was comparable with the control solid slabs, however, HCRC slab with concrete pipes showed 7 to 8 percent reduction in flexural strength with 19 to 20 percent reduction in self-weight. All the tested specimens performed well in shear as no shear failure was observed. This study reveals that HCRC slabs with locally available material having hollow cross section elements can be used for the construction of cast in-situ monolithic construction of one-way slabs with ordinary construction techniques. Doi: 10.28991/cej-2020-03091597 Full Text: PDF

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Wang, Ru Heng, and Juan Han. "Experimental Research and Theoretical Analysis on Flexural Capacity of Prestressed Concrete Hollow Slabs Strengthened with CFRP." Advanced Materials Research 368-373 (October 2011): 519–26. http://dx.doi.org/10.4028/www.scientific.net/amr.368-373.519.

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The purpose of this paper is to focus on analyzing its flexural capacity under concentrated force at the two points of a symmetrical load after the 21 old and new different degrees of damege to prestressed concrete hollow slab is strengthened with CFRP by the different paste modes and paste quantities.Meanwhile,according to the initial loading of prestressed concrete hollow slab specimens in which the plastic state, based on the elastic-plastic theory,it presents the theoretical calculation formula of the ultimate bearing capacity produced with the consideration of the secondary load of the prestressed concrete hollow slab strengthened with CFRP.Through the experimental value of the old and new specimens compared with the theoretical one, It provides design suggestions and reference for the prestressed concrete hollow slab strengthened with CFRP,and provides an experimental basis for the repairing and reinforcing practical application of the Wenchuan disaster area.

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25

Zhang, Zhen Hao, Wei Jun Yang, and Zhi Gang He. "Experiment and Theory Study on Ultimate Bearing Capacity of Reinforced Concrete Tubular Hollow Continuous Slab." Applied Mechanics and Materials 204-208 (October 2012): 782–85. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.782.

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The tubular hollow slab inside which GBF high-strength thin-wall pipes are placed is a new type of hollow structure. First the ultimate bearing capacity of tubular hollow continuous slab is measured by experiment. Then the ultimate bearing capacity of the tubular hollow continuous slab is studied by plastic limit analysis method. And the complete solution of structural ultimate load under condition of full internal force redistribution is solved. The study show that the measured values of ultimate load are all a little larger than the theoretical values of ultimate load, which shows that the tubular hollow slab develop full internal force redistribution. So it can be concluded that the tubular hollow slab has fine performance of plastic internal force redistribution.

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26

ILYIN, Nikolay Alekseevich, Denis Aleksandrovich PANFILOV, and Aleksandr Petrovich SHEPELEV. "NEW ARRANGEMENT FOR REINFORCEMENT OF HOLLOW CORE PANEL OF BUILDING FLOOR." Urban construction and architecture 4, no. 2 (June 15, 2014): 86–93. http://dx.doi.org/10.17673/vestnik.2014.02.14.

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The proposed device is referred to building sphere. Its oriented to strengthening of reinforced concrete hollow fl oor slab, damaged due to diff erent reasons including fi re or technological accident. Possible results of this device using are: signifi cant increase of strength and rigidity of fl oor slabs; signifi cant increase of real fi re-resistance of slabs; smooth unloading of damaged slab; regulation of unloading amount of reinforced slab. This proposed device is simple in design, its characterized by economy in using, negligeable restraint of operating envelope in altitude. Strengthening of reinforced fl oor slab does not require starting dimensions changes; steel is economize in mass and cut because of more strength reinforcement rods. Labor is saving.

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27

Kalimur Rahman, M., Isam A. Mahmoud, and M. H. Baluch. "Finite Element Modeling of Prestressed Hollow Core Slab Strengthened with CFRP Sheets in Flexure and Shear." Key Engineering Materials 400-402 (October 2008): 531–36. http://dx.doi.org/10.4028/www.scientific.net/kem.400-402.531.

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Precast concrete construction with prestressed precast hollow core slab as floor and roofing is being extensively used in the Gulf region. These one way slabs are sometimes subjected to unforeseen loads with a partition wall in shear zone or as a cantilever. A detailed experimental program involving full-scale load testing of hollow core slabs has been conducted involving testing of virgin and CFRP strengthened slabs in flexure and shear. This paper presents the results of the experimental and numerical evaluation of flexural and shear behavior of the hollow core slabs. The hollow-core slabs were modeled using the nonlinear finite element software DIANA and the load deflection behavior and ultimate capacity were evaluated numerically. For the FE model, concrete was modeled using Drucker-Prager with tension cut-off failure criterion, and Von-Mises plasticity with multilinear isotropic hardening was used to model the prestressing strands. Comparison between the experimental and the numerical results indicated that the finite element model predicted experimentally determined results successfully.

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Cui, Hui Chen, Ji Liang Liu, and Ming Jin Chu. "Research on Performance of Precast Two-Way Hollow Slab Shear Wall with Cast-In Situ Boundary Elements." Applied Mechanics and Materials 477-478 (December 2013): 655–59. http://dx.doi.org/10.4028/www.scientific.net/amm.477-478.655.

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Low cyclic loading tests were carried out for one precast two-way hollow slab shear wall with cast-in-situ boundary elements and one RC shear wall. The seismic performance of precast two-way hollow slab shear wall was analyzed. The test results indicated that macroscopic vertical cracks appeared along precast slab vertical holes of precast two-way hollow slab shear wall. The failure characteristics of the precast two-way hollow slab shear wall were significantly different from that of the reinforced concrete shear wall. Shear failure could be avoided and seismic performance of the new type shear wall was good.

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Sui, Zheng-Ang, Kun Dong, Jitong Jiang, Shutong Yang, and Kexu Hu. "Flexural Behavior of Fire-Damaged Prefabricated RC Hollow Slabs Strengthened with CFRP versus TRM." Materials 13, no. 11 (June 4, 2020): 2556. http://dx.doi.org/10.3390/ma13112556.

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In this paper, carbon fiber reinforced polymer (CFRP) and textile reinforced mortar (TRM) strengthening techniques were proposed to retrofit and strengthen fire-damaged prefabricated concrete hollow slabs. A total of six slabs, from an actual multi-story masonry building, were tested to investigate the flexural performance of reinforced concrete (RC) hollow slabs strengthened with TRM and CFRP. The investigated parameters included the strengthening method (CFRP versus TRM), the number of CFRP layers, and with or without fire exposure. One unstrengthened slab and one TRM strengthened slab served as the control specimens without fire exposure. The remaining four slabs were first exposed to ISO-834 standard fire for 1 h, and then three of them were strengthened with CFRP or TRM. Through the four-point bending tests at ambient temperature, the failure modes, load and deformation response were recorded and discussed. Both CFRP and TRM strengthening methods can significantly increase the cracking load and peak load of the fire-damaged hollow slabs, as well as the stiffness in the early stage. The prefabricated hollow slabs strengthened by CFRP have better performance in the ultimate bearing capacity, but the ductility reduced with the increase of CFRP layers. Meanwhile, the TRM strengthening technique is a suitable method for the performance improvement of fire-damaged hollow slabs, in terms of not only the load capacity, especially the cracking load, but also the flexural stiffness and deformation capacity.

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Dong, Han, Xiu Qin Cui, and Shi Ge Lv. "Influence of Span-Depth Ratio to the Ductile Property in Prestressed Concrete Hollow Slab." Advanced Materials Research 671-674 (March 2013): 492–95. http://dx.doi.org/10.4028/www.scientific.net/amr.671-674.492.

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The numerical analysis method is applied to simulate the whole process of bending. Keeping the section dimensions and the types of loads constant in prestressed concrete hollow slab with mid-strength spiral-rib steel wire, strength of concrete, strength of steel bar, reinforcement ratio, span-depth ratio and stretching control stress are analyzed and compared. The influence of span-depth ratio to the ductile property in prestressed concrete hollow slab is discussed by numerical simulation.

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Han, Dong, Xiu Qin Cui, Rong Wu, and Shi Ge Lv. "Influence of Reinforcement Ratio to the Ductile Property in Prestressed Concrete Hollow Slab." Advanced Materials Research 671-674 (March 2013): 693–96. http://dx.doi.org/10.4028/www.scientific.net/amr.671-674.693.

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The numerical analysis method is applied to simulate the whole process of bending. Keeping the section dimensions and the types of loads constant in prestressed concrete hollow slab with mid-strength spiral-rib steel wire, strength of concrete, strength of steel bar, reinforcement ratio, span-depth ratio and stretching control stress are analyzed and compared. The influence of reinforcement ratio to the ductile property in prestressed concrete hollow slab is discussed by numerical simulation.

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Vaitkevičius, Vitoldas, Ernestas Ivanauskas, Arminas Štuopys, and Mindaugas Daukšys. "MODIFYING THE COMPOSITION OF HOLLOW-CORE SLAB CONCRETE." Engineering Structures and Technologies 1, no. 1 (May 17, 2009): 58–64. http://dx.doi.org/10.3846/skt.2009.07.

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The questions of the extruded concrete composition and the possibilities of modifying it are very important for the technology for the extruded concrete. The gained experience of working with the extruders of hollow core slabs shows that the operators of such equipment frequently choose an improper strategy for the production process. The main drawbacks are as follows: a) the use of fairly stiff mixture that is far above the necessary Vebe consistency class V2 for this technology; b) the over saturation of the mixture with coarse aggregates which determines a low compaction factor of the mixture; c) the rejection of using concrete admixtures which causes equipment overloads or led to its exploitation in the limitary conditions. Besides, the experience of using extruders proves that all parameters predicted by standards and other norms (for example, concrete strength class C40/50 or C50/60 including water cement ratio W/C<0,45) are obtainable without large efforts. Therefore, the main criteria for the suitability of such concrete modifi cation have rather technological character including the lowest energy consumption during shaping and the compaction of the semi manufacture of the reinforced article as well as the highest structural strength or stability of the fresh concrete slab. Whereas the mechanical properties (mainly strength) of such hardened concrete are mostly within acceptable values, it cannot be treated as the main criterion for optimizing the extruded concrete composition. Extruded concrete compositions used for producing hollow-core slab were chosen for technological and laboratory scale investigations. The amount of Portland cement in the concrete mixture was 335…370 kg/m3, sand made 0/2 mm grade – 330…440kg/m3 and 0/4 mm grade – 680…510 kg/m3; the amount of coarse aggregates 200…325 kg/m3 and 755…825 kg/m3 for grades 2/8 mm and 11/16 mm respectively; W/C ratio 0,34…0,39. The crushing strength of the extruded concrete was within 57…68 MPa and more (the results of technological trials). The character of the structure and the compaction level of the extruded mixture are the indicators of its technological suitability. Adding common lignosulfonate-based plasticizer (up to 1% of the cement mass) or a very small dose (0,2…0,3%) of the new generation super plasticizer with or without air entrainment agent could improve the structural and technological properties of such concrete. The experience obtained during laboratory scale investigations and on trials for the manufacturing lines of hollow core slabs shows that the main cause of such improvements is a better dispersion of cement particles in the stiff concrete mixture while the cohesion of the mixture of the freshly extruded article rests near unchanged. The effectiveness of such improvement was proven within the process of observing the level of the consumption of compaction energy – it was registered by the control console of extruders. After improvements in the concrete mixture were carried out, the consumption of compaction energy was reduced by 20…25 %. Investigations into concrete cores drilled-out from the hardened articles prove the apparently better structure of the modifi ed concrete while concrete strength and other physical properties rests rather unchanged (if the mixture W/C ratio rests unchanged). Improvements to concrete structure manifests by the absence of ‘air pockets’ (large pores of irregular form, air gaps trapped during mixture extrusion and compaction), more gradually distributed and comparatively small pores, the absence of internal concrete structure zones with cleft aggregates and loose sand particles and evenly coloured concrete (which proves a very good distribution of cement particles). The use of an air entrainment agent in the stiff concrete mixture allows reducing the dose of the plasticizer (super plasticizer) and reduces the density and crushing strength of the extruded concrete. Such was negligible during investigation and technological trials (up to 1,5 % of concrete density and about 3 % of strength), it was concluded that the air entrainment agent could be used in the extruded concrete for articles the exploitation conditions of which are severe, for example, for class XF2 etc.

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Cui, Xiu Qin, Bing Guo, and Yan He. "Study on the Influencing Factors of Deflection-Span Ratio under Standard Load in Prestressed Concrete Hollow Slab." Advanced Materials Research 446-449 (January 2012): 156–60. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.156.

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The numerical analysis method is applied to simulate the whole process of bending. Keeping the section dimensions and the types of loads constant in prestressed concrete hollow slab with mid-strength spiral-rib steel wire, strength of concrete, strength of steel bar, reinforcement ratio, span-depth ratio and stretching control stress are analyzed and compared. The influence of strength of concrete, strength of steel bar, reinforcement ratio, span-depth ratio and stretching control stress on deflection-span ratio under standard load of prestressed concrete hollow slab is discussed by numerical simulation.

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Cui, Xiu Qin, Hua Wei Zhao, and Nan Zhao. "Discussion on the Influencing Factors of Deflection-Span Ratio at Failure in Prestressed Concrete Hollow Slab." Advanced Materials Research 255-260 (May 2011): 174–77. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.174.

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The numerical analysis method is applied to simulate the whole process of bending. Keeping the section dimensions and the types of loads constant in prestressed concrete hollow slab with mid-strength spiral-rib steel wire, span-depth ratio, reinforcement ratio, strength of concrete, strength of steel bar and stretching control stress are analyzed and compared. The influence of span-depth ratio, reinforcement ratio, strength of concrete, strength of steel bar, and stretching control stress on deflection-span ratio at failure of prestressed concrete hollow slab is discussed by numerical simulation.

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Cui, Xiu Qin, Bing Guo, and Zhong Ren Feng. "Discussion on the Influencing Factors of Cracking Bending Moment in Prestressed Concrete Hollow Slab." Applied Mechanics and Materials 94-96 (September 2011): 136–40. http://dx.doi.org/10.4028/www.scientific.net/amm.94-96.136.

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The numerical analysis method is applied to simulate the whole process of bending. Keeping the section dimensions and the types of loads constant in prestressed concrete hollow slab with mid-strength spiral-rib steel wire, strength of concrete, strength of steel bar, reinforcement ratio, span-depth ratio and stretching control stress are analyzed and compared. The influence of strength of concrete, strength of steel bar, reinforcement ratio, span-depth ratio and stretching control stress on ratio of cracking bending moment and design bending moment of prestressed concrete hollow slab is discussed by numerical simulation.

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Surianinov, Mykola, Stepan Neutov, and Iryna Korneieva. "Comparative analysis of strength and deformation of reinforced concrete and steel fiber concrete slabs." E3S Web of Conferences 166 (2020): 06003. http://dx.doi.org/10.1051/e3sconf/202016606003.

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The results of experimental studies of the steel fiber influence on the bearing capacity, deformability and crack resistance of reinforced concrete multi-hollow plates are given. We investigated a serial floor slab and a similar one, but with the addition of steel fiber. Both plates are factory-made. For testing, the testing apparatus was designed and manufactured that made it possible to study full-size floor slabs in laboratory conditions. The tests were carried out according to a single-span scheme with the replacing equivalent load. The loading was carried out by applying two concentrated strip vertical loads along the plate width. The load was applied in steps of (0.04 ÷ 0.05) from the breaking load. Each stage ended with exposure lasting up to 10 minutes with fixing all the necessary parameters. Deformations were measured using dial gauges. From the moment the first crack appeared in the stretched zone of concrete, the process of crack formation and opening was monitored. At each level, using the Brunell tube, the width of their opening and height were measured. The moment of cracking in both slabs began at the same relative strain. It has been established that the bearing capacity and crack resistance of a slab of combined reinforcement using steel fiber are respectively 50 and 44% higher than that of a similar reinforced concrete slab. The maximum deflection of the slab of combined reinforcement is 37.5% lower than that of conventional reinforced concrete. The destruction of both slabs occurred under loads, when the relative deformations in the compressed zone of concrete reached 0.80×10-3 and 1.10×10-3 for reinforced concrete and steel-fiber concrete slabs, respectively, the difference is 37.5%.

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Hosny, Abdelhadi, Ezzeldin Yazeed Sayed-Ahmed, Amr Ali Abdelrahman, and Naser Ahmed Alhlaby. "Strengthening precast-prestressed hollow core slabs to resist negative moments using carbon fibre reinforced polymer strips: an experimental investigation and a critical review of Canadian Standards Association S806-02." Canadian Journal of Civil Engineering 33, no. 8 (August 1, 2006): 955–67. http://dx.doi.org/10.1139/l06-040.

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Behaviour of precast-prestressed hollow core slabs has been extensively studied when these slabs are subjected to positive bending moments, a practical application typical of hollow core slabs. However, in many projects it may be required to have an overhanging part of the roof to act as a cantilever. In doing so, and using precast-prestressed hollow core slabs, the slabs would be subjected to negative moments, atypical for hollow core slabs. In this paper, the behaviour of precast-prestressed hollow core slabs is experimentally investigated when they are subjected to negative bending moments. A proposed strengthening detail to increase the negative moment resistance of hollow core slabs using bonded carbon fibre reinforced polymer (CFRP) strips is presented. The CFRP strips were bonded to the top side of full-scale precast-prestressed hollow core slabs in the negative moment zone in different configurations. In two of the tested slabs the bond between the prestressing strands and the concrete was initially broken (during casting of the slabs) in the negative moment zone. The slabs with the bonded CFRP strips were tested to failure and the load–deflection behaviour was recorded. The results of the tests are presented and the strength enhancement of the hollow core slabs using the proposed technique is reported. The increase in the negative moment resistance of the CFRP-bonded hollow core slabs experimentally determined is also compared with the CSA-S806-02 prediction for the moment resistance of concrete elements with bonded CFRP strips.Key words: carbon fibre reinforced polymer (CFRP) strips, hollow core slab, flexure strengthening, prestressed concrete, precast slabs, prestressing strands.

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Hua, Xudong, Xingwei Xue, Junlong Zhou, and Hai Zhang. "Experimental and Numerical Analysis of The Used Hollow Slab." MATEC Web of Conferences 175 (2018): 01036. http://dx.doi.org/10.1051/matecconf/201817501036.

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The actual bearing capacity of a bridge in active service is crucial to the structure, but such data is generally difficult to obtain. In order to obtain the actual ultimate bending capacity of the used hollow slab, a destructive test of a hollow slab, which has been used ten years, has been carried out. Moreover, based on the experimental analysis of the material parameter data, a three-dimensional finite element nonlinear analysis model of the used hollow slab was established. Through the experiment and finite element analysis of the used hollow slab, the comparisons of the failure mode, crack propagating and ultimate bending capacity were focused on. The main conclusions obtained through the study are as follows: (1) Strand is a kind of stable prestressed material, which can maintain good mechanical properties for a long time; (2) The used hollow slab still maintains good ultimate bending capacity, although underwent a decreased rigidity due to long-term cumulative damage; (3) The total strain fracture model is qualified for simulating the nonlinearity of concrete material, and can obtain the ultimate bearing capacity of reinforced concrete structure effectively as well as simulates the development of cracks well.

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Li, Hai Tao, Andrew J. Deeks, Li Xin Liu, Xiao Zu Su, and Dong Sheng Huang. "Mechanics Comparison between Hollow Floor and Solid Floor." Applied Mechanics and Materials 94-96 (September 2011): 654–57. http://dx.doi.org/10.4028/www.scientific.net/amm.94-96.654.

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In this paper both a hollow floor and the corresponding solid floor are analysed by using finite element software and the results are compared. The comparison is made through a detailed finite element study between a column-supported cast-in-situ hollow floor filled by tube with its solid counter-part. The orientation of the tube fillers causes the stiffness of the hollow slab to be orthotropic, potentially changing the distribution of load carrying between the two orthogonal directions. The inclusion of the hollows also potentially increases the flexibility of the slab. Recommendations for design of column-supported cast-in-situ concrete floors compared with the solid floor are then made with respect to distribution of design moments and calculation of deflections. Thus the reference was given to the designer.

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Tusnin, Alexander, and 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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Derkowski, Wit, and Mateusz Surma. "Influence of concrete topping on behaviour of prestressed Hollow Core floor slabs on flexible supports." Budownictwo i Architektura 12, no. 1 (March 11, 2013): 107–14. http://dx.doi.org/10.35784/bud-arch.2180.

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Slim Floors (SF) are the structures made of the Hollow Core (HC) slabs supported on the slender beams, where the beam height is usually slightly greater than the height of precast slab element. With the increase of the supports' deflection, the deformation of the HC slab occurs, and in consequence, additional transverse normal and shear stresses appear in the precast element, which can cause a diagonal cracking and destruction of external webs of this element. It may also result in longitudinal cracks on bottom surface of the slab. Despite the frequent implementation of this type of structures, the existing standard EN 1168 gave only a brief record of the need to take the reduction in design shear capacity into account, but is not given any calculation procedure. It is widely believed that reduction of unfavourable effects of shear stress in the HC slab’s web can be achieved by filling the cores with concrete or arrangement of the monolithic layer or concrete topping. The fib guidelines are practically the only one document which allows to determine the shear capacity of SF slabs, including the influence of concrete topping or core filling – brief description of this design model is presented in the paper. In order to determine the effect of concrete topping on the behaviour of prestressed HC slabs on the flexible supports, a number of calculation analyzes were performed, which take into account the effects of thickness of the concrete topping, the value of the friction coefficient between the concrete topping and the precast element, the sequence of concreting of vertical joints and topping layer and the amount of supplementary reinforcement in the topping. The results of the calculations, and the conclusions derived from them, are presented in the article.

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Barbieri, Diego Maria, Yuechi Chen, Enrico Mazzarolo, Bruno Briseghella, and Angelo Marcello Tarantino. "Longitudinal Joint Performance of a Concrete Hollow Core Slab Bridge." Transportation Research Record: Journal of the Transportation Research Board 2672, no. 41 (June 17, 2018): 196–206. http://dx.doi.org/10.1177/0361198118781653.

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Hollow core slab bridges are constructed by placing prefabricated or prestressed box beams adjacent to each other, grouting the small longitudinal space (hinge-joint) between the slabs and casting a reinforced concrete deck. The longitudinal cracking appearing at hinge-joint locations leads to a premature deterioration of the deck. This paper presents a theoretical and experimental study of a hollow core slab bridge composed of three beams and a cast-in-place deck. A real-size specimen was built according to Chinese code specifications. The behavior of the longitudinal joints was investigated by applying the standard vehicle load. The tests do not highlight any longitudinal cracks. A finite element model was created from the experimental data. A finite element parametric analysis revealed some practical design indications regarding the following inputs: deck thickness, concrete strength, and hinge-joint steel bars. Furthermore, these analyses testify that C-shape and X-shape stirrups do not play an active role in preventing the joint longitudinal cracks. This research confirms the reliability of the design method, at least for static loads, while further studies are needed to investigate the effect of both periodical loadings and different temperatures on upper and lower surfaces of the beams.

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Jamil, Hasnat, Morshed Alam, and Jay Sanjayan. "Thermal Performance of Hollow-Core Slab Ventilation System with Macro-Encapsulated Phase-Change Materials in Supply Air Duct." Buildings 9, no. 2 (February 22, 2019): 51. http://dx.doi.org/10.3390/buildings9020051.

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The aim of this research was to evaluate the effectiveness of phase-change materials (PCMs) incorporated into the supply air duct of a hollow-core slab ventilation system. Both experimental and numerical approaches were adopted in this investigation. In the experimental work, the air was passed through a PCM-incorporated aluminum air duct, and the temperature at various points of the duct was recorded. Computational fluid dynamics models of the PCM-incorporated supply air duct and the hollow-core slab were developed and validated with the respective experimental data. The validated models were used to simulate the performance of PCM-incorporated hollow-core slabs during summer in Melbourne, Australia. The results showed that the reduction in temperature fluctuation varied with the way the PCM was incorporated inside the supply air duct. The temperature difference was maximum and was maintained for a longer period when the PCM was spread to all four internal surfaces of the supply air duct. The results also showed that the effectiveness of the combined PCM–air duct–hollow-core slab system in reducing the temperature fluctuation was lower than the individual performance of the PCM–air duct and hollow-core concrete slab for a given inlet temperature condition during the simulated period. This was because the integration of PCMs in the supply air duct resulted in a precooling effect which reduced the difference between the amplitude of slab inlet temperature swing and average slab temperature. As a result, the reduction in temperature fluctuation due to the thermal mass of the hollow-core slab was 21% lower in the presence of PCMs compared to the no-PCM case.

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Li, Ming, Zhe Zhe Sun, Wei Jian Zhao, and Yong Liu. "Research Progress on Reinforced Concrete Laminated Slab in China." Applied Mechanics and Materials 174-177 (May 2012): 263–67. http://dx.doi.org/10.4028/www.scientific.net/amm.174-177.263.

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The development of new generation prefabricated reinforced concrete structure is still at an early stage in China. Reinforced concrete laminated slab, as an important horizontal load carrying member, is paid much attention to in research. Based on the research results about it in China, the progress of which is summarized, including the form, characteristics and experimental research of sandwich laminated slab, anti-ribbed laminated slab, and hollow laminated slab etc. Finally, the further research is prospected.

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Xuan, Wei Hong, Yong Wan, Yu Zhi Chen, and Pan Xiu Wang. "A New Type of Cast In Situ Reinforced Concrete Biaxial Hollow Slab with Property of Thermal Insulation." Advanced Materials Research 368-373 (October 2011): 448–51. http://dx.doi.org/10.4028/www.scientific.net/amr.368-373.448.

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The construction technology and fundamental principle of a new kind of cast-in-situ reinforced concrete biaxial hollow slab with property of thermal-insulating is proposed in this paper. Compared with ordinary floor, the biaxial hollow slab is well load-carrying capacity in two-direction, light weight and thermal -insulating property.

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Ramli, Mohd Zakwan, Harlina Mohd Mahayudin, G. Hayder, Z. M. Hafiz, M. Daud, and A. M. Salleh. "The Importance of Lightweight Concrete Technology Development for IBS Industry in Malaysia Based on Cost Comparison between Concrete Slab and Hollow Core Slab: A Case Study of LRT Car Park Project." Applied Mechanics and Materials 567 (June 2014): 637–41. http://dx.doi.org/10.4028/www.scientific.net/amm.567.637.

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There are several issues related to the implementation of new Industrialised Building System (IBS) technology in Malaysia which some of them are the awareness among industry players, and lack of development on the new technology in the industry. The main constraint that has always been discussed by the IBS players is time and cost. To have more reliable product or technology in terms of cost and time, it is important to craft and develop new idea as well as technology in our own country. The objective of this study was to highlight the cost comparison between cast in-situ concrete slab and hollow core slab (lightweight) which it can be a starting point for future research on the development of new lightweight IBS technology in Malaysia to get the most reliable cost with latest technology by using local resources. Informations on costs and work durations are collected and analysed between two floors using two different construction methods (hollow core slab and conventional concrete slab). Hollow core slab (lightweight IBS) has similar or less cost with shorter construction period (30% shorter) for the project.

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Wang, Yu, Xiang Zhao, Neng Luo, and Lin Wang. "Experimental Study on Reinforcing the Prestressed Concrete Hollow Slab with CFRP." Advanced Materials Research 230-232 (May 2011): 31–34. http://dx.doi.org/10.4028/www.scientific.net/amr.230-232.31.

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According to the practical situation (loaded by the second time), nine pieces of prestressed concrete hollow slabs which had been reinforced with CFRP were experimented on. And symmetric load was putted on the three-point of the hollow slabs. In this paper, the effects of different pasting methods and quantity of CFRP on mechanical performance and reinforcement effect of prestressed concrete hollow slabs which were damaged in varying degrees were studied. And the ultimate bearing capacity, failure mode, types of cracks and load-deformation curves of test specimen after being reinforced was analyzed systematically. After contrasting and analyzing the trial value of prestressed concrete hollow slabs, a simple, economic and reasonable reinforcing program was obtained.

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Kim, Seung Hun. "Behaviors of Void Slab with GFRP Reinforcement." Applied Mechanics and Materials 166-169 (May 2012): 1756–59. http://dx.doi.org/10.4028/www.scientific.net/amm.166-169.1756.

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Use of hollow material in slab can reduce self-weight and deflection than solid slab with GFRP reinforcement. In this study, bending tests were carried out to evaluate the bending performance of void slabs with GFRP reinforcements. Test results showed that bearing capacity at the compression zone seriously affected the ultimate bending strength of void flexural members. For a design of the void flexural members with GFRP bars, it needs to use the higher concrete strength and to arrange the void foams considering of the crushing failure and distribution of strains and stresses.

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Nagy, Balázs, and Elek Tóth. "Finite Element Analysis of Composite Ceramic-Concrete Slab Constructions Exposed to Fire." Applied Mechanics and Materials 861 (December 2016): 88–95. http://dx.doi.org/10.4028/www.scientific.net/amm.861.88.

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In this research, conjugated thermal and fluid dynamics simulations are presented on a modern hollow clay slab blocks filled pre-stressed reinforced concrete beam slab construction. The simulation parameters were set from Eurocode standards and calibrated using data from standardized fire tests of the same slab construction. We evaluated the temperature distributions of the slabs under transient conditions against standard fire load. Knowing the temperature distribution against time at certain points of the structure, the loss of load bearing capacity of the structure is definable at elevated temperatures. The results demonstrated that we could pre-establish the thermal behavior of complex composite structures exposed to fire using thermal and CFD simulation tools. Our results and method of fire resistance tests can contribute to fire safety planning of buildings.

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ARAÚJO, D. L., and G. D. C. PINTO. "Fire behavior of shallow prestressed hollow core slabs from computational modeling." Revista IBRACON de Estruturas e Materiais 13, no. 2 (April 2020): 398–432. http://dx.doi.org/10.1590/s1983-41952020000200011.

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Abstract Prestressed hollow core slabs are one of the structural systems whose use has increased the most in recent years in Brazil due to its efficiency and versatility. They can be used in many types of structural systems, such as masonry, precast concrete, cast-in-place concrete and steel structures. However, there are few analytical models to evaluate the fire behavior of hollow core slabs. In a simplified way, the fire resistance is evaluated indirectly through the minimum distance of the surface in contact with fire to the reinforcement axis. In this paper, some numerical models in finite element software were developed to analyze the variation of temperature with ﬁre exposure time of shallow hollow core slabs, focusing on the presence of voids in the transversal section of the slab. The 500 °C isotherm method applied to 20 cm high slabs confirmed the Standard Fire Resistance obtained from the tabular method. However, when applied to shallow prestressed hollow core slabs that are 16 cm high, the 500 °C isotherm method indicated that the Standard Fire Resistance of these slabs is lower than values obtained from tabular methods.

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Journal articles on the topic 'Hollow concrete slab'

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