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Book ChapterDOI

Experimental and analytical investigations on two-way flexural capacity of biaxial voided slab

01 Jan 2021-Vol. 81, pp 233-247
TL;DR: In this paper, the authors explored the possibility of biaxial voided slabs as a substitute for conventional reinforced concrete slabs and found that the flexural capacity of the two-way slab with voids is the same as a solid slab, with a minor reduction in its flexural stiffness.
Abstract: The rise in urbanisation and subsequent demand for infrastructure accelerates the use of concrete as a construction material. Conventional design practices need large member sizes to fulfil architectural and structural requirements. Hence, the size of structural members such as slab, beam, column, etc., significantly affects the quantity of concrete used. This calls for the need to optimise the use of concrete to reduce the self-weight of structure. The present study explores the possibility of biaxial voided slabs as a substitute for conventional reinforced concrete slabs. A typical biaxial voided slab eliminates concrete from the middle of the floor slab by introducing voids and it leads to a significant reduction in self-weight, about 30–50%. However, these voids reduce the sectional area of slab concrete, which leads to a reduction in flexural stiffness and shear resistance. The behaviour of the biaxial voided slab subjected to two-way flexure is discussed. Experiments are carried out to determine two-way flexural behaviour of the two-way slab with sphere shape voids by adopting 16-point loads. The obtained experimental results of strength and serviceability criteria are compared for slabs with and without voids. It is found that the flexural capacity of the two-way slab with biaxial voids is the same as a solid slab, with a minor reduction in its flexural stiffness. Furthermore, an analytical study is carried out based on the yield line analysis to predict the flexural capacity of the slab and compared with experimental results. It is evidenced that 16-point load is equivalent to 89% of uniformly distributed load and the flexural capacity of void slabs can be predicted by using yield line analysis as used in the conventional solid slab.
Citations
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Journal ArticleDOI
TL;DR: In this paper, the applicability of conventional methods for solid slabs in the design standards, such as ACI 318 (2014), EN 1992-1-1 (2004) and IS 456 (2000), to predict the punching shear capacity of the voided slab is examined.

16 citations

Journal ArticleDOI
01 Mar 2021
TL;DR: In this article, a comprehensive statistical analysis of factors that influence the design parameters of slab is presented, and it is found that low correlation between that there is high but negative correlation found between Effective Depth Required and spacing_x and Inputs variable is able to explain well only two variables Effective_depth require and Spacing_x.
Abstract: The slab is a fundamental component of any building that are used as floors and roofs. It is, most commonly, made up of reinforced concrete. Slabs are the structural elements whose thickness is significantly less than their other dimensions. Slabs can have different shapes and conditions of support. It may be a solid, waffle-type or a ribbed slab. They are categorized as one way and two-way slab according to their load-carrying nature. In this paper, a comprehensive statistical analysis of factors that influence the design parameters of slab is presented. It is found that there is low correlation between that there is high but negative correlation found between Effective Depth Required and spacing_x and Inputs variable is able to explain well only two variables Effective_depth require and Spacing_x. The effect of magnitude of different input variables on output variables and interaction of combination of different input variables on output variables for design of Two-Way Slab is also performed.

2 citations

Journal ArticleDOI
01 Jun 2021
Journal ArticleDOI
TL;DR: In this article, the effect of the position of voids in the voided flat slabs has been studied and it is concluded that the concrete has no role at below the neutral axis of structural void cross-section for all specimens including controlled specimens.
Abstract: Abstract In recent modern buildings, voided slabs have been implemented because of the high reduction of their weight up to 35 %. Also, CO2 emission takes place which was developed from mass concrete. Due to percentage reduction of concrete, it leads to help the pollution free environment, eco-friendly and also more sustainable. On voided flat slabs, a minimal study has been recorded. In this current study, an approach has been made to study the effect of the position of voids in the voided flat slabs. Two groups of seven specimens each, one slab in each group was a controlled flat slab specimen with zero number of voids kept as a reference specimen, while the others were voided slabs. In each group, the number of voids were used based on the positions. The designation of the specimens is made depending on the number of voids placed and the diameter of the rebar used in the specimens. Group-A was reinforced with 8 mm diameter rebars, and Group-B was reinforced with 6 mm diameter rebars. The parameters of the study are the void positions and the rebar diameter. The specimens were subjected to a gradually concentrated load through the short column up to failure. The load carrying capacity of both voided and controlled flat slabs tested have almost same. It indicates that, the inactive concrete below the neutral axis where high density polyethylene (HDPE) recycled hollow spheres have been provided in the flat slab has shown no impact on load carrying capacity of the test specimens. However, the presence of the punching shear can be seen in the specimens where the voids are positioned near the columns and supports. Besides, ABAQUS program (A finite element based software) was used to perform the finite element analysis for profoundly illustrating the experimental findings and performing a parametric study. It is concluded that the concrete has no role at below the neutral axis of structural voided flat slab cross-section for all specimens including controlled specimens (0VS6, 0VS8). Also, it is noticed that the finite element analysis obtained results have shown more or less same as experimental results. From the present study, it is evident that behaviour of voided flat slabs are different from simply supported voided flat slabs.
References
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Journal ArticleDOI
TL;DR: In this paper, the flexural capacities of one-way hollow slab with donut type hollow sphere were evaluated and shown to have good flexural capacity such as strength, stiffness and deflection.
Abstract: This paper presents the flexural capacities of one-way hollow slab with donut type hollow sphere. 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 biaxial hollow slab system is widely known as one of the effective slab system which can reduce self-weight of slab. A biaxial hollow slab has hollow spheres within slabs in order to reduce self-weight of slabs. The capacities of biaxial hollow slab are influenced by the shapes, volume and materials of hollow spheres. According to analytical studies, the hollow slab with donut type hollow sphere had good flexural capacities such as strength, stiffness and deflection. To verify the flexural capacities of this hollow slab, flexural tests were performed on the one-way hollow slabs. Five test specimens were used for test parameters. One was conventional RC slab and others were hollow slabs. The test parameters included two different shapes and materials of plastic balls. The shape parameters were donut and non-donut forms. And the material parameters were general plastic and glass fiber plastic.

17 citations

Journal ArticleDOI
TL;DR: In this article, the authors evaluated the punching shear strength of voided slabs according to the arrangement of voids through experimental tests and numerical simulations, and determined that the void-based reduction of the cross-sectional area at the control perimeter and the ratio of the length of the controlling perimeter to the effective depth of the slab were the factors that influenced the punching-shear strength.

12 citations

Journal ArticleDOI
TL;DR: In this article, the authors evaluated the flexural behaviors of void reinforced concrete (Reinforced Concrete) and precast concrete (PC) slabs with polystyrene void forms.
Abstract: Where the self weight of the overall RC(Reinforced Concrete) or PC(Precast Concrete) floor system needs to be considered, the quantity of in-situ concrete required can be reduced by the application of polystyrene void forms to slab. In this study, flexural behaviors of void RC and PC slab with polystyrene form were evaluated to understand the effect on the self weight reduction of the slab. This paper presents experimental works and finite element analysis on the bending of the void slabs. Six specimens were tested. The main parameters of experiments were the slab types (RC and PC), the types and arrangement details of polystyrene form, and the thickness of slab. Structural behaviors of void slabs were evaluated on the basis of failure mode, load-displacement curve, and ultimate strengths. Test results indicated that nominal strengths by ACI code agreed well with experimental results. The results of analysis were compared with the results of test for estimating the validity of analysis model.

8 citations

Book ChapterDOI
01 Jan 2019
TL;DR: In this article, simulations were carried out by using finite element software DIANA (Displacement Analyzer) to investigate the flexural capacity of the biaxial hollow slab.
Abstract: Biaxial hollow slab is a type of slab in which concrete from the middle of the slab (floor) has been eliminated by means of voids. This type of slab system is mainly used as reinforced concrete flat slab. Its main advantage is reduction in self-weight (about 30–50%). However, the presence of voids reduces the area of slab concrete, which leads to reduction in the flexural stiffness and shear resistance. In this study, simulations were carried out by using finite element software DIANA (Displacement Analyzer) to investigate the flexural capacity of the biaxial hollow slab. Parametric studies were carried out to compare the effect of different types of voids on the behaviour of the slab.

4 citations