Biaxial Hollow Slab Research Articles

Biaxial Hollow Slab Under Seismic Load

In reinforced concrete building structures, the slab is the component with the largest volume of concrete of all the superstructure components. Various innovations were carried out. Currently, the use of Hollow Core Slab (HCS) to reduce the load on building superstructures is widely used in Indonesia. Another type of slab is Biaxial Hollow Slab (BHS) as an alternative to reduce slab concrete volume. BHS is considered capable of reducing concrete consumption by up to 30% -50% of conventional concrete without reducing the performance of the slab itself. It could be reducing the load on the working superstructure can reduce the influence of seismic loads on the foundation. Indonesia is a country with an earthquake zone, so the use of BHS must be considered with seismic design categories that are appropriate to the earthquake zones in Indonesia. This research is focused on giving information about the numerical study of application BHS in 10th story building with design seismic category D. The thickness used in this study is equivalent thickness of BHS to solid slab. The absence of beams in weak axis and the present of perimeter beam by utilization BHS, gives the result BHS has sufficient capacity to carry the workload.

Reduced Volume Approach to Evaluate Biaxial Bubbled Slabs’ Resistance to Punching Shear

The bubbled slab, a type of reinforced concrete (RC) slab with plastic voids, is an innovative design that employs a biaxial distribution of voiding formers within the slab to reduce the slab’s self-weight while preserving a load-carrying capacity that is approximately comparable to that of solid slabs. This paper presents a new approach for figuring out the effective critical shear perimeter of voided slabs using the reduced-volume concept of concrete. This approach aims to reduce the coefficient of variation of the current design standards, namely the ACI 318-19 and Eurocode 2, for assessing the slabs’ resistance to punching shear. Our experimental program investigated the impact of voiding former patterns and the location of an opening near a column on the punching shear resistance of biaxial hollow slabs. The factors under consideration included the opening’s size, location, and distance from the loaded area, as well as the voiding formers’ placement concerning the critical shear boundaries. The results of experiments on 10 full-scale, 2000 × 2000 × 230 mm, reinforced concrete biaxial voided slabs with an opening are presented in this study. Two design expressions were used to estimate the biaxial hollow slabs’ shear strength. These expressions take into account the reduced volume of concrete and the distribution of voiding formers up to the section 4d from the periphery of the column. The proposed approach to determine the effective punching shear perimeter has the lowest coefficient of variation among the methods suggested by these standards. This indicates the validity of our proposed expressions. The coefficient of variation of the proposed expressions does not exceed 0.057.

Análise dinâmica de uma laje aliviada biaxial submetida a ações humanas

Abstract The bi-axial hollow slab is the result of applying a technology that removes concrete from the least useful region and replaces it with hollow plastic spheres. This technique leads to material economy and self-weight saving, without considerable inertial loss, enabling larger and more flexible spans. Consequently, these spans are vulnerable to unwanted vibrations and dynamic acceleration caused by external actions, such as movements produced by human activity. This way, understanding the dynamic behavior of this technology and confronting it with normative limits on the project phase is essential for a good performance in the serviceability limit state, bringing comfort to the user. This paper studies the dynamic behavior of a bi-axial hollow slab submitted to human actions, such as jumping, dancing, clapping, moving the body, and moving and clapping at the same time. For that, this work made a numerical model of the structure and applied dynamic actions to it. The numerical results show that, for most of the actions, normative limits are satisfied, but the slab presents excessive accelerations in the case of jumping and dancing.

Structural Behaviour of Biaxial Hollow Slab and its Application in Construction Industry

Structural Behaviour of Biaxial Hollow Slab and its Application in Construction Industry

Reduced area approach for predicting punching shear resistance of biaxial hollow slabs with openings

Due to the inclusion of hollow plastic spheres in bubbled slab systems, the shear resistance is greatly reduced. Also, the existence of the opening in the vicinity of columns takes away part of the concrete responsible for resisting shear forces and unbalanced moments, which in turn further reduces the punching shear capacity of the slab-column connection. In this study, experimental and theoretical investigations had been carried out on bubbled slabs with 2000 × 2000 × 230 mm dimensions. The investigated parameters were the size, position, distance of opening relative to the column stub, and the location of bubbles relative to the critical shear perimeter. A new calculation approach for determining punching shear resistance for bubbled slabs was developed. The proposed modification for calculating the effective critical perimeter showed an appropriate range of agreement of the punching shear strength, which is calculated by the methods adopted by (ACI 318, Eurocode 2, BS 8110, and AS 3600) codes, in comparison to the experimental data. The average ratios of the test results to the calculated punching shear capacity determined according to the proposed approach are between 1.007 and 1.417 with a standard deviation of 0.039–0.186 and a coefficient of variation of 0.038–0.131.

Bubble Deck Slab as an Innovative Biaxial Hollow Slab – A Review

Slab is the most important member in any building structure which consume large amount of concrete. The slab self-weight is large due to large consumption of concrete in producing slab. Therefore, bubble deck slab is an innovative and newly designed biaxial hollow slab system that had been introduced in order to overcome this problem. Bubble deck slab is a revolutionary method which was developed by Jorgen Bruenig from Denmark in the 1990s. The bubble deck slab had been designed and constructed with plastic hollow bubbles in the middle part of slab to eliminate the concrete which does not perform any structural function and at the same time reducing the slab self-weight. Thus, the self-weight of bubble deck slab can be reduced about 30-50% than conventional concrete slab; that can reduce the loads acting on columns, walls and foundations. Finally, the use of bubble deck slab can give many benefits as compared to conventional concrete slab such as improve the structural performance of slab, reduce the materials and cost, efficiency and faster construction time, and it is also a green product. The aim of this paper is to give some of the reviews from previous studies related to bubble deck slab.

Comparative Study on Bubble Deck Slab and Conventional Reinforced Concrete Slab – A Review

Slab is the most important structural member of any building structure and also one of the largest member consuming concrete.Thus, the alternative biaxial hollow slab system known as bubble deck slab had been introduced as one of the effective slab systemsthat improves building design and performance while reduce the self-weight by eliminating concrete part in the middle ofconventional slab which does not contribute to the structural performance. The effective hollow slab systems that dramaticallyreduce the slab weight by 30-50%. Moreover, concrete usage is reduced as 1 kg of recycled plastic replaces 100 kg of concrete. Thenew prefabricated construction technology using bubble deck slab is recently applied in many industrial projects in the world. Ithas many advantages as compared to conventional reinforced concrete slab such as lower total cost, reduced material use,enhanced structural efficiency, decreased construction time, and is a green. The aim of this paper is to discuss the significance andvarious properties of bubble deck slab against conventional reinforced concrete slab based on various studies and researches thathad been done.

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

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.

비선형유한요소해석을 통한 이방향 중공슬래브의 전단거동분석

비선형유한요소해석을 통한 이방향 중공슬래브의 전단거동분석

Experimental Investigations on the Strength and Serviceability of Biaxial Hollow Concrete Slabs

Biaxial hollow slab is a reinforced concrete slab system with a grid of internal spherical voids included to reduce the self-weight. This paper presents an experimental study of behavior of one-way prestressed concrete bubbled slabs. Twelve full-scale one-way concrete slabs of (3000mm) length with rectangular cross-sectional area of (460mm) width and (150mm) depth. Different parameters like type of specimen (solid or bubbled slabs), type of reinforcement (normal or prestress), range of PPR and diameter of plastic spheres (100 or 120mm) are considered. Due to the using of prestressing force in bubbled slabs (with ratio of plastic sphere diameter D to slab thickness H, D/H=0.67), the specimens showed an increase in ultimate load capacity ranging between (79.3% and 125%) and a decrease in the deflection at service load of about (9.8% to 12%) with respect to the control bubbled reinforced concrete slab. Also, it is found that, the bubbled slabs have about (79% to 86%) of the ultimate load capacity of a similar reference solid slab. At the same time the influence of voids present in the bubbled slabs is reflected in a decrease in the first cracking load by about (14.8% to 29.6%) in comparison with solid slabs.
 

도넛형 중공슬래브의 휨 강도 및 휨 강성

This paper presents the flexural capacities of biaxial hollow slabs with donut type hollow shapes. Recently, various types of slab systems which can reduce self-weight of slabs have been studied as the height and width of building structures increase. A biaxial hollow slab system is widely known as one of the effective 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 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 such as strength and stiffness, flexural tests were performed. Three test specimens were planned to verify the effect of test parameters. One was conventional RC slab and others were donut type hollow slabs. The donut type hollow slabs have two different fixing methods of plastic balls. The one is used diagonal steel cage and the other is fixed with only its geometrical shapes without additional steel cage.

도넛형 이방향 중공슬래브 뚫림전단 강도 및 파괴거동에 대한 실험적 연구

This paper presents the punching shear strength and failure behavior of biaxial hollow slab with donut type hollow-shaper. Until now, 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. According to previous studies, the biaxial hollow slab has weakness in slab-column connection compared with solid slab. And previous studies pointed out reduced cross-section area of concrete by hollows as the cause. It is assumed in this study that the shape of hollows and the location of hollow-shaper exert influence on the punching shear strength of biaxial hollow slabs. Therefore, donut type hollow-shaper which was suggested as the optimal hollow shape in previous study was used in this study. To verify the punching shear strength and failure behaviour of donut type biaxial hollow slab, punching shear tests were conducted. 4 test specimens were used for test parameters. One was conventional RC slab and 3 were hollow slabs. The test parameter was the area of critical section which were determined by the number of hollow-shaper around the column. The punching shear strength of the donut type biaxial hollow slabs are 87%~103% of solid slabs and superior to generic biaxial hollow slabs. And punching shear cracks occurred at the first perimeter line of donut type hollows.

Flexural Capacities of Reinforced Concrete Two-Way Bubbledeck Slabs of Plastic Spherical Voids

This paper presents the flexural capacities of R.C two way hollow slabs of plastic spherical voids, also known as BubbleDeck slab system. Recently, various types of slab systems which can reduce the self-weight of slabs have been studied as the height and width of building structures rapidly increase (1). A biaxial hollow slab system is widely known as one of the effective slab systems which can reduce the self-weight of slabs (1). A BubbleDeck slab has a two-dimensional arrangement of voids within the slabs to reduce self-weight (2). The behavior of BubbleDeck slabs is influenced by the ratio of bubble diameter to slab thickness. To verify the flexural behavior of this BubbleDeck slab such as ultimate load, deflection, concrete compressive strain and crack pattern, two-dimensional flexural tests were tested by using special loading frame. Six test of specimens were used. Two were a conventional RC slab and four were BubbleDeck slabs having void diameter to slab thickness ratios of (0.51, 0.64 and 0.80). Results have shown that the crack pattern and flexural behavior depend on the void diameter to slab thickness ratio. The ultimate load capacities for BubbleDeck slabs having bubble diameter to slab thickness of (0.٥1 and 0.64) were the same of solid slabs, while when bubble diameter to slab thickness of (0.80) the ultimate capacities were reduced by about (10%).

도넛형 이방향 중공슬래브의 부착특성에 관한 실험적 연구

이 연구는 도넛형 이방향 중공슬래브에 매입된 이형철근의 부착특성 및 부착강도 산정을 위한 기초적인 연구이다. 도넛형 이방향 중공슬래브의 철근 부착특성 및 부착강도 산정을 위해 pull-out test를 수행하였다. 도넛형 중공형성체는 슬래브 내부에 배치되어 철근과 중공형성체 사이에 내부의 피복이 형성된다. 이러한 내부피복두께는 외부피복두께보다 상대적으로 작은 피복두께를 가지며 중공형상에 따라 2.5db보다 작은 내부피복두께가 형성되기 때문에 철근의 부착에 영향을 미치게 된다. 또한 중공형성체가 일정 간격으로 떨어져 배치되어 있으므로 인장철근을 감싸고 있는 피복두께의 조건이 철근의 길이방향으로 변하게 된다. 따라서 도넛형 이방향 중공슬래브의 부착특성을 알아보기 위해서 중공형성체 형상에 따라 부착구간을 구분하였다. 구간별로 내부피복두께에 따른 부착응력-슬립 관계를 확인하였으며, 중공형성체 전 구간에 걸친 부착응력분포를 확인하여 철근의 길이방향에 따른 부착응력의 발현정도를 확인하였다. 또한 구간별 부착응력-슬립 관계를 기반으로 하여 도넛형 중공슬래브의 부착강도를 산정할 수 있는 부착강도 산정 방법을 제안하였다.

중공형상 및 재료의 영향을 고려한 도넛형 이방향 중공슬래브의 일방향 전단강도

Dept. of Architectural Engineering, College of Engineering, Hanyang University, Seoul 133-791, KoreaABSTRACT This paper presents the shear capacities of biaxial hollow slab with donut type hollow sphere. Recently, varioustypes of slab systems which can reduce self-weight of slabs have been studied for increasing constructions of taller and larger build-ing structures. A biaxial hollow slab system is widely known as one of the effective slab system, which can reduce self-weightof slab. According to previous studies, the hollow slab has low shear strength, compared to solid slab. Also, the shear capacitiesof biaxial hollow slab are influenced by the shapes and materials of hollow spheres. However, the current code does not providea clear computation method for the shear strength of hollow slab. To verify the shear capacities of this hollow slab, one-way sheartests were performed. Four test specimens were used for test parameters. One was conventional RC slab and others were hollowslabs. 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. The results showed that the shear strengthsvaried depending on hollow shapes and materials used in the slab.Keywords : biaxial hollow slab, hollow sphere, shear strength, experimental study, flat plate slab

A New Type of Cast <i>In Situ</i> Reinforced Concrete Biaxial Hollow Slab with Property of Thermal Insulation

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.

2방향 중공슬래브 구조시스템의 비선형 지진거동 평가

2방향 중공슬래브 구조시스템의 비선형 지진거동 평가

Shear Capacity of Biaxial Hollow Slab with Donut Type Hollow Sphere

This paper presents the shear capacities of biaxial 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. According to previous studies, the hollow slab had low shear strength, compared with solid slab and the shear capacities of biaxial hollow slab are influenced by the shapes and materials of hollow spheres. In addition, the present code does not provide a clear computation method for the shear strength of hollow slab. To verify the shear capacities of this hollow slab, shear tests were performed. Four 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

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

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.

Punching Shear Strength of Biaxial Hollow Slab with Donut Type Hollow Sphere

This paper presents the punching shear capacities of biaxial 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. According to previous studies, the hollow slab has weakness in slab-column connection. In addition, the present code does not provide a clear computation method for the punching shear strength of hollow slab. In this study, the special type of cage was used to improve punching shear capacities and fix the hollow spheres in critical section. To verify the punching shear capacities of this biaxial hollow slab, punching shear tests were performed. Four test specimens were used for test parameters. One was conventional RC slab and three were hollow slabs. The test parameter was the areas of critical section which were determined by the number of hollow spheres in critical section.