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Title |
Shear Performance of Board-type Two-way Voided Slab
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Authors |
최현민(Hyeon-Min Choi) ; 박태원(Tae-Won Park) ; 백인관(In-Kwan Paik) ; 김제섭(Je-Sub Kim) ; 한주연(Ju-Yeon Han) |
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DOI |
http://dx.doi.org/10.4334/JKCI.2015.27.6.651 |
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Keywords |
수행능력 평가 ; 판형중공슬래브 ; 중공재 고정장치 ; 수평전단강도 performance evaluation ; board-type voided slab ; fixing material ; horizontal shear strength |
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Abstract |
Currently, social demands for long span building structures are increasing due to architectural planning purposes and economic efficiency. As a result, lighter board-type voiding materials were suggested. With the use of board-type voiding materials, a slab is able to become light weight and convenient. This process efficiently eliminates concrete where it is not required; considerably diminishing dead weight while maintaining the flexural strength of the slab. The reduction in concrete also allows for overall cost reductions and design flexibility. Also it can be ease with fixing the voided material that is composed of one body form. Although board-type voiding materials are ideal, the top and bottom concrete plates lack integrity. Because of this, test results show horizontal cracking towards the tops and bottoms of the concrete columns, or webs, connecting the slabs. The key to correcting this problem is to increase the shear strength. In order to increase the shear strength of the structure, horizontal shear area must increase. R70(100)-D-F has the largest horizontal shear area as it also shows stronger strength. As a result, shear strength (Vnh) is dependent on the horizontal shear area (N).Vnh=α×0.16×√fck(πD²/4)×N(α=1.8125). The web columns have a shear span to depth ratio (a/d) that is less than 2; which classifies it as a deep beam. In this case, however, the shear strength of the deep beams may be as much as 2 to 3 times greater than that predicated conventional equations developed for members of normal proportions. As a result, α is suggested as an extra coefficient in the equation for shear strength (Vnh).
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