Flexural Capacities of One-Way Hollow Slab with Donut Type Hollow Sphere

Kim, Byoung-Hoon; Chung, Jaywan; Choi, Hyun Ki; Lee, Seung Chang; Choi, Chil-Sung

doi:10.4028/www.scientific.net/kem.452-453.773

Cited by 21 publications

(10 citation statements)

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“…A voided slab system using spherical or oval plastic balls as voidshapers was developed to derive the main advantages of voided slabs while eliminating the slab's directivity and reducing its self-weight (BubbleDeck Technology, 2008). Previous studies (BubbleDeck Technology, 2008;Kim et al, 2009Kim et al, , 2011 have noted that voided slab systems show good flexural strength equivalent to that of a solid slab having the same thickness. However, voided slabs are vulnerable to deterioration of the shear strength owing to the use of less concrete at the slab web that resists shear.…”

Section: Introductionmentioning

confidence: 93%

One-way shear strength of circular voided reinforced concrete floor slabs

Chung

Choi

Lee³

et al. 2015

Proceedings of the Institution of Civil Engineers - Structures

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Generally, voided reinforced concrete floor slabs in building structures have a lower shear strength compared with solid slabs owing to the reduction in their cross-sectional area. This study shows that the void shape and material of the void-shaper also influence the shear strength of voided slabs. To verify these assumptions, one-way shear tests were conducted for four test specimens. The first was a conventional solid slab and the others were voided slabs.The voids had toroidal or 'doughnut' shapes as well as non-doughnut shapes. The void-shaper was made of polypropylene plastic and glass-fibre-reinforced plastic. The test results showed that the shear strength of doughnuttype voided slabs was 73-78% of a solid slab and was superior to that of existing voided slabs. The shear crack angle changed with the void shape. A finite-element analysis was conducted to evaluate the influence of these parameters on the shear behaviour of the doughnut-type voided slab. Notation a shear span b v width of the void b w sum of smallest web thicknesses C Rd,c coefficient derived from tests D j diagonal length of the panel for measuring shear deformation d effective depth of the specimen d j depth of the panel for measuring shear deformation f ck specified compressive strength of concrete G shear modulus of elasticity H height of the slab h j width of the panel for measuring shear deformation k factor of size effect N number of doughnut-type void-shapers that are located in the shear crack region P cr measured load when first shear crack occurred R curvature radius of void edges V c nominal shear strength provided by concrete without shear reinforcement V HS shear strength of a doughnut-type void-shaper with varying materials V HS,Total sum of the shear strength of the doughnut-type void-shapers V n nominal shear strength of the voided slab without shear reinforcement V Rd,c nominal shear strength provided by concrete without shear reinforcement V u ultimate shear strength AE shear factor AE Doughnut shear factor of the doughnut-type voided slab ª 1 measurement of shear strain ª 2 measurement of shear strain ª s shear strain of the slab ª xy shear strain of the void-shaper ä 1 deformation of the panel in the diagonal direction ä 2 deformation of the panel in the diagonal direction å a strain of the void-shaper in the vertical direction å b strain of the void-shaper in the diagonal direction å c strain of the void-shaper in the horizontal direction Ł shear crack angle r tensile reinforcement ratio of the slab ô V shear stress of the void-shaper 336

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Section: Introductionmentioning

confidence: 93%

One-way shear strength of circular voided reinforced concrete floor slabs

Chung

Choi

Lee³

et al. 2015

Proceedings of the Institution of Civil Engineers - Structures

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“…Biaxial voided slab is reinforced concrete slab with void formers made of shapes like sphere, cuboid, and donut (Bub-bleDeck Technology 2008;Chung et al 2010;Kim et al 2011; Daliform Group 2014) and placed in the middle of slab in between the top and bottom of the reinforcing mesh. It reduces the self-weight of slab up to 50% in comparison with conventional solid slab without any significant change in its structural performance (Björnson 2003;Harding 2004).…”

Section: Introductionmentioning

confidence: 99%

“…Experimental or analytical and numerical studies were conducted to evaluate the one-way flexural capacity of biaxial voided slab with different shapes of void formers. These studies provided evidence that biaxial voided slabs have slightly lower stiffness and similar strength compared to that of solid slab (BubbleDeck Technology 2008;Kim 2011;Ibrahim et al 2013;Valivonis et al 2014). The slab with donut-shaped void showed almost similar flexural capacity to that of solid slab.…”

Section: Introductionmentioning

confidence: 99%

“…The slab with donut-shaped void showed almost similar flexural capacity to that of solid slab. The material properties and strength of donut-shaped void highly affect the flexural strength of the voided slab (Kim et al 2011). The flexural stiffness of spherical-shaped voided slab is 80-90% of solid slab, however, the void slab showed the same flexural strength as that of solid slab (Midkiff 2013).…”

Section: Introductionmentioning

confidence: 99%

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Effect of void former shapes on one-way flexural behaviour of biaxial hollow slabs

Sagadevan

Rao

2019

Int J Adv Struct Eng

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The Two-way hollow slab system (biaxial voided slab) is an innovative slab system, being adopted all over the world as an alternate for the conventional solid slab. It reduces the self-weight up to 50% in comparison with solid slabs without significant change in its structural performance. The voided slab consists of void formers in shapes like spherical, donut, and cuboid. Experimental and analytical investigations were carried out to study the behaviour of biaxial voided slab under one-way flexure. Voided slab specimens were prepared and tested with two different shapes of voids namely sphere and cuboid, which were manufactured using recycled polypropylene. Comparison of experimental and analytical studies showed that the ultimate load-carrying capacity of voided slabs was higher or similar to that of solid slab. An analytical study was carried out using the yield line analysis in conjunction with Indian Standards. It was found that the capacity of voided slab can be estimated by yield line analysis. The flexural stiffness of voided specimen is approximately 50% lesser in comparison with solid slab of identical dimensions and reinforcement at yield stage. The reduction in flexural stiffness is mainly due to the presence of void former and the maximum void ratio at a section defines the flexural stiffness of the voided slab. Nevertheless, the deflection is under serviceable limit for both the specimens for 75% of ultimate load. Ultimately, it is found that the behaviour of voided slabs under one-way flexure can be predicted by provisions of Indian Standards with necessary correction for loss of cross-section caused by voids.

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“…4 Kim et al used five biaxial voided slab specimens 300 × 1,250 × 250 mm in dimensions containing plastic balls of different shapes to study their flexural capacity. 5 Chung et al examined the behavior of biaxial hollow-core slabs containing ellipsoidal balls 140 mm in height. 6 Chung et al studied stiffness and flexural strength in biaxial voided slabs using six specimens 210 mm in thickness.…”

Section: Introductionmentioning

confidence: 99%

Investigation of flexural and shear behaviors of biaxial voided slabs containing steel cages

Khouzani

Zeynalian

Hashemi

et al. 2019

Structural Concrete

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In some of biaxial voided slabs, spherical or ellipsoidal plastic balls enclosed in steel cages are used to eliminate ineffective concrete. To investigate the bending and shear behavior of this system, five full‐scale specimens were cast including two bending specimens for investigating bending capacity and cracking distribution as well as three shear specimens used to study the shear capacity, cracking distribution, and concrete casting effect on the shear behavior. Moreover, the effects of the steel cage rods were studied on the bending and shear capacity. It was found that while both solid and biaxial voided specimens exhibited almost similar failure mode, both the bending and shear capacity of biaxial voided specimens were affected by the steel cages. In contrast, the voided specimens exhibited a significantly lower shear capacity than the solid ones while the different concrete casting methods had no effects on the capacity and behavior of biaxial voided specimens. Finally, a comparison was made with experimental results and ACI 318‐14, MC 2010, and Eurocode 2 recommendations.

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Flexural Capacities of One-Way Hollow Slab with Donut Type Hollow Sphere

Cited by 21 publications

References 0 publications

One-way shear strength of circular voided reinforced concrete floor slabs

One-way shear strength of circular voided reinforced concrete floor slabs

Effect of void former shapes on one-way flexural behaviour of biaxial hollow slabs

Investigation of flexural and shear behaviors of biaxial voided slabs containing steel cages

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