Voided Slab System Research Articles

Comparative Study of and Voided Slab System and Conventional RCC Slab

This paper presents the flexural capacities of R.C.two-way hollow flat slabs with plastic voids. Recently, various types of slab systems which can reduce the self-weight of slabs have been studied as the height and span of building structures rapidly increase. To verify the flexural behaviour of this voided slab such as flexural stiffness, ultimate load, deflection, stresses and concrete compressive strain were studied.FEM model was created in ANSYS workbench 2022 for both conventional solid flat slab and voided slab. U-Boot beton from “daliform group building innovation Italy” was used as void former in this study. The dimensions of U-boot is 520×520mm and with 180mm and 160mm height. Dimension of FEM slab model is 8500×8500 mm with 500×500 column support at all four corners. Three different slab of 280mm, 300mm and 320mm was created. In addition, manual analysis of solid slab and voided slab was carried out using direct design method as per IS-456(2000). And further, design is checked to verify that it satisfies all design and serviceability criteria given as per IS-456(2000).Results obtain via theoretical calculation and FEM model simulation for both solid and voided slab were compared. The aim of this paper is to discuss and compare flexure behaviour of solid slab and voided slab and to study changes in inertia, stiffness and reduction in weight, of the slab by void formation.

Behavior of two-way reinforced concrete voided slabs enhanced by steel fibers and GFRP sheets under repeated loading

Moderately thick voided slab systems are used in the construction of long-span slab buildings to incorporate lower weight on foundations and enhance the thermal and sound insulation of the slab. In some cases, these slabs required an enhancement if there is an increase in the applied loads or a defect in their construction properties. This research is focused on giving better enhancement techniques for such cases with keeping the flexural ductile failure of the tested slabs. Eight slab specimens of (1000 × 1000 mm2) were cast and tested as two-way simply supported slabs. The tested specimens consist of one solid slab and seven voided slabs. The study variables comprised the nature of the slab (solid and voided), the thickness of the slab (100 and 125 mm), the presence of steel fibers (0% and 1%), and the number of GFRP layers. The voids in slabs were made using high-density polystyrene of dimensions (200 × 200 × 50 mm) with a central hole of dimensions (50 × 50 × 50 mm) to give the shape of donat. These voids are made at the ineffective concrete zones to give a reduction in weight by (34%–38%). The slabs were tested as simply supported slabs under partial uniform repeated loading. The results of tested specimens showed that the enhancement with a combination of steel fibers and GFRP sheets gave the least deflection (4.2 mm), higher ultimate loading capacity (150 kN), larger stiffness at cracking, and at ultimate load (52.5, and 35.7 kN/mm) respectively, more ductility index (1.35), and larger energy absorption (1098.7 kN mm)..At the same stage of loading, the effect of adding steel fibers by (1%) for voided slab leads to a decrease in the deflection by (30%) and increase the ultimate loads by (31%). Therefore the strengthening technique adopted in this research enhances the behavior of moderately thick voided slabs effectively and preserves a ductile flexural behavior.

Flexural Strength and Stiffness of Donut-Type Voided Slab

The voided slab system has been known as an effective technique to replace a heavy reinforced concrete slab system without the decrease in flexural strength. However, according to the previous studies, the flexural capacities such as flexural strength, stiffness and ductility of the voided slabs were practically lower than that of the solid slabs depending on the void shapes and details. Therefore, in this study, an analytical and experimental study were conducted to derive the optimal void shape and details focused on the flexural capacities of voided slabs. Based on a finite element (FE) analysis, a donut-type void shaper, which was a hexahedron with rounded edges and a hole penetrating the center, was suggested as the optimal shape in voided slabs, and an experimental study was conducted to verify flexural capacities of the donut-type voided slab. The flexural strength, stiffness and deflection of the donut-type voided slab were investigated by void shape and fixing method of void shaper as variables. The ductility of voided slab was also evaluated, because ductility is as important as strength for the safe design of slab member. The test results showed that the flexural strength of the donut-type voided slabs was equivalent to 98% and 105% that of the solid RC specimen, and the donut-type voided slab specimens had enough ductility for the flexural member. The stiffness of the donut-type voided slab was decreased about 8~9% compared with the solid slab, but it was improved up to 7% compared to the non-donut-type voided slab. Based on test results, the flexural design method of the donut-type voided slab associated with the void shape and fixing device of void shaper was suggested, and it was confirmed that the donut-type voided slab is one of the efficient alternatives to replace heavy flat plate slabs.

A numerical study on flexural behavior of biaxial voided slabs containing steel cages

Several roofing systems have been proposed given their significance in concrete structures, in terms of time and resources. A biaxial voided slab system is introduced to improve the solid slab system's performance by creating voids in the concrete and removing ineffective material. In this study, the bending behavior of voided slabs is investigated numerically. For this purpose, a numerical ABAQUS model is presented and then verified using available experimental results. Then, a parametric study was carried out focusing on the plastic balls and their spacing, steel cages, and the position of plastic balls relative to the slab height. As shown in this paper, the presence of plastic balls improves the flexural capacity, because of steel cages. However, the spacing between plastic balls and their position have not a significant effect on flexural behavior. Finally, the numerical results were compared with the ultimate moment capacities from ACI 318-19, AS 3600-18, EC2 2004, and CSA A23.3-19, and were shown that considering steel cages have better consistencies with numerical results.

Effects of temperature changes on voided slab integral abutment bridge

Integral Abutment Bridges (IABs) are joint-less bridges whereby the deck is monolithic with the abutment walls. IABs are outperforming their non-integral counterparts in economy and safety. Thermal effects introduce significantly complex and nonlinear soil-structure interaction into the response of abutment walls and piles of the IB. This paper carried out comprehensive study on voided slab system with five spans bridge each span is 17m long. The bridge has been modelled using SAP software. The abutments and pile foundations are modeled taking into consideration the soil-structure interaction. The study covered a design uniform temperature change of (10, 20, 30, 40 and 50) °C. To gain a better understanding of the mechanism of load transfer due to thermal actions, a 3D frame anal¬ysis is carried out on the above mentioned IABs. The results showed wide range of different linear and lightly non-linear relationships between temperature range, deformations and moments. The paper highlighted the serious effect of the deformations resulting from the repeated temperature change which causes drop in soil or bombing at the abutments ~ embankment contact zone.

Comparison of Environmental Impact of Three Different Slab Systems for Life Cycle Assessment of a Commercial Building in South Korea

The environmental impacts of the construction stage should be considered since a large amount of building materials are used to construct a building at this stage. Studies on the improvement of construction techniques or the application of newly developed construction methods for reducing the environmental impacts are relatively scant compared to other topics of studies. This study aimed to assess and compare the environmental impacts of the ordinary solid slab, the flat plate slab and the voided slab system during the construction phase. A process-based quantitative model was adopted to evaluate the environmental impacts and the comparative results were analysed to demonstrate the significant characteristics of the environmental impacts of the construction of slab in a building. The assessment results show that the environmental impacts from the ordinary solid slab are the highest and the voided slab system is the lowest among three slab systems. As the slab system of the studied building was replaced, it was shown that the environmental impact indicators showed the decreased tendency. Based on the results of environmental impact reduction from the ordinary solid slab, the flat plate slab and the voided slab system, the voided slab system would have the least environmental impact in all indicators.

Evaluation of Carbon Dioxide Emissions amongst Alternative Slab Systems during the Construction Phase in a Building Project

Global warming is now considered to be one of the greatest challenges worldwide. International environmental agreements have been developed in response to climate change since the 1970s. The construction industry is considered one of the main contributors to global warming. In order to mitigate global warming effects, the construction industry has been exploring various approaches to mitigate the impacts of carbon dioxide emissions over the entire life cycle of buildings. The application of different structural systems is considered a means of reducing the carbon dioxide emissions from building construction. The purpose of this research is to assess the environmental performance of three different slab systems during the construction phase. In this study, a process-based life cycle assessment (LCA) method was applied in order to evaluate the level of performance of the three slab systems. The results showed total CO2 emissions of 3,275,712, 3,157,260, and 2,943,695 kg CO2 eq. for the ordinary reinforced concrete slab, flat plate slab, and voided slab systems, respectively. The manufacturing of building materials is by far the main contributor to CO2 emissions, which indicate 3,230,945, 3,117,203, and 2,905,564 kg CO2 eq., respectively. Comparing the building materials in the three slab systems, reinforcing bars and forms were significant building materials to reduce the CO2 emissions in the flat plate slab and voided slab systems. In this study, reinforcing bars were the main contributor to lowering the carbon dioxide emissions in the flat plate slab and voided slab systems. The results of this study show that amongst all the three different slab systems, the voided slab system shows the greatest reduction potential. Moreover, replacing the ordinary reinforced concrete slab system by alternative methods would make it possible to reduce the carbon dioxide emissions in building projects.

Reducing Greenhouse Gas Emissions and Costs with the Alternative Structural System for Slab: A Comparative Analysis of South Korea Cases

The construction industry is one of the main contributors to the production of large volumes of greenhouse gases, since it consumes a large quantity of energy and construction materials. The purpose of this research is to assess the environmental impacts and economic efficiency of the voided slab system compared to the ordinary reinforced concrete slab. A life cycle assessment (LCA) and the total cost of construction were calculated to evaluate the performance of both slab systems. Additionally, the total costs of construction for both cases were determined based on the unit price of the building materials. The results of this study indicate that manufacturing building materials contributes most to the total GHG emissions where concrete is responsible for nearly 1/2 of all emissions. Additionally, forms are the second largest contributor of the total GHG emissions and account for nearly 40% and 15% of emissions for the ordinary reinforced concrete slab and the voided slab system, respectively. This study verified that the voided slab system indicated better environmental performance than the ordinary reinforced concrete slab. The total GHG emissions of the ordinary reinforced concrete slab were 256,599 and 13,989 kg·CO2·eq, for concrete and forms, respectively. Additionally, the total GHG emissions of the voided slab system were 224,945 and 12,211 kg·CO2·eq. The reduction of GHG emissions from Case 1 for aboveground floors and Case 2 for underground parking was 12.3% and 12.7% over the ordinary reinforced concrete slab, respectively. The economic efficiency of the ordinary reinforced concrete slab and the voided slab system were assessed by comparison of the total costs of construction. This showed a total cost reduction of 12.3% and 11.2% for the case of applying the voided slab system to the aboveground floors and underground parking, respectively. Thus, replacing the ordinary reinforced concrete slab by the voided slab system in the aboveground floors and the underground would make it possible to decrease not only the emissions of GHG, but also the cost of construction.

Comparison of Carbon Dioxide Emissions of the Ordinary Reinforced Concrete Slab and the Voided Slab System During the Construction Phase: A Case Study of a Residential Building in South Korea

The construction industry not only consumes a lot of energy but also emits large volumes of carbon dioxide. Most countries have established target reduction values of the carbon dioxide emissions to alleviate environmental burdens and promote sustainable development. The reduction in carbon dioxide emissions in the construction industry has been taking place in various ways as buildings produce large quantities of the carbon dioxide over their construction life cycle. The aim of this study is to assess and compare the carbon dioxide emissions of an ordinary reinforced concrete slab and the voided slab system applied to a case study involving a commercial-residential complex building in South Korea. Process-based life-cycle assessment (LCA) is adopted to compute the carbon dioxide emissions during the construction phase, which includes all processes from material production to the end of construction. The results indicate that the total CO2 emissions are 257,230 and 218,800 kg CO2 for the ordinary reinforced concrete slab and the voided slab system, respectively. The highest contributor to CO2 reduction is the embodied carbon dioxide emissions of the building materials, which accounts for 34,966 kg CO2. The second highest contributor is the transportation of the building materials, accounting for 3417 kg CO2.

Evaluation of the Floor Impact Sound Insulation Performance of a Voided Slab System Applied to a High-Rise Commercial Residential-Complex Building

Multi-unit dwellings, such as apartment housing, town houses, and flats, are some of the most common housing types in Korea, as well as in other countries. Such multi-unit dwellings are considered an effective means to overcome the housing problems of high-density population in urban areas, owing to their high efficiency of land utilisation. However, interlayer noise complaints, such as footsteps or dragging items in apartment housing, are an inevitable problem in apartment dwelling conditions, because each household in an apartment shares walls and ceilings with other households. This paper presents the results acquired from the field test of the floor impact sound insulation performance of a voided slab system as applied to a commercial residential-complex building in South Korea. The results have shown that adopting the voided slab system for a commercial residential-complex building increased floor impact sound insulation performance. The test results show that the sound insulation performance of the voided slab system applied in the building for lightweight and heavyweight floor impact sound reached (47 and 41) dB, respectively. Based on the results of the field tests, it is expected that the application of the voided slab systems to the slabs of the apartment dwellings would be effective, and offer outstanding sound insulation performance. Moreover, it is expected that the floor impact sound insulation performance would be further improved, if the floor finishing materials, such as carpet or other types of flooring material, would first be installed onto the floor.

Experimental analysis of one-way composite steel deck slabs voided by circular paper tubes: Shear strength and moment–shear interaction

In order to improve structural efficiency, environmental performance, and constructability, a new type of one-way composite voided slab system (TUBEDECK) has been recently proposed which combines profiled steel decks with cast-in-situ RC slabs. Because eliminating concrete volume to optimize flexural strength can significantly reduce the shear strength of nonprestressed concrete or composite slabs without shear reinforcement, a clarification of the shear resistance capacity is required. In this study, shear tests on a total of 12 specimens were conducted with slab thickness, the presence or absence of voids and/or steel decks, and tension reinforcement ratio as variables. The results show that combined flexure and shear dominated the behavior of both voided (V) slabs and TUBEDECK (TD) slabs, and web-shear cracking did not affect strength. Predicted shear strength based on the minimum web width was too conservative. Conversely, the shear strength prediction equations, which were proposed on the basis of the real cross-sectional area of concrete, predicted the capacity of both V slabs and TD slabs from a reasonably conservative perspective. A discussion on the influence of moment–shear interaction is also included, and an interaction design model is proposed in a further investigation.

Two-Way Flexural Behavior of Donut-Type Voided Slabs

Voided slab systems were developed using segmented void formers such as spherical or oval plastic balls for two-way slab applications. This type of slab is expected to behave like a general two-way reinforced concrete slab because it has segmented voids, rather than the continuous voids of hollow core slabs. However, the structural behaviors of two-way voided slabs with segmented voids have not been clearly verified. Therefore, this paper analyzes the possibility of applying a donut-type two-way voided slab, which was investigated with a 12-point two-way bending test focused on global behaviors, including its load bearing capacity, flexural stiffness, ductility, deflection, and load distribution. In addition, the design method of a donut-type two-way voided slab was reviewed through the yield line method. The test results showed that one donut-type two-way voided slab acted like a conventional two-way reinforced concrete slab with the load distributed evenly between the different directions; however, another donut-type two-way voided slab with different characteristics showed uneven load distribution with different crack patterns. In addition, the yield line method could predict the load bearing capacities of the donut-type voided slabs with approximately 95% accuracy.

슬림 프리캐스트 슬래브 데크를 사용한 I-슬래브 시스템의 휨 성능에 관한 실험적 연구

Recently, the interest in precast voided slab system for buildings is growing up according to the demand for high quality control and the increase in slab thickness. A hollow slab system is widely known as one of the effective slab system which can reduce self-weight of slab. However, in case of conventional precast voided slabs, It is uncertain to apply these slab system to two-way slabs because It have a rectangular shaped void-former. In this study, I-slab system that applies plate type and octagonal pillar type void-former on slim precast slab deck is developed, and then flexural capacity of the I-slab system Is evaluated by 4-pointed banding test. In addition, flexural capacities of I-slab system along the longitudinal and transverse axis are compared to verify the applicability of I-slab system to two-way slabs. Test results showed that I-slab had enough flexural strength and ductility for slab member. In addition, I-slab system Is found to be sufficiently possible to apply on two-way slabs.

Computer‐Aided Design of Prestressed Concrete Cellular Bridge Decks

Abstract: This paper illustrates the application of an effective optimization procedure for the design of prestressed concrete cellular bridge decks consisting of single‐ and two‐cell box girders or voided slab systems. An approximate live load moment analysis using the finite‐strip method and finite‐difference techniques that determines moment sensitivities to changes in the deck depth and flange thickness is proposed for box girder decks. The optimization process is much simplified by eliminating the need of finite‐strip reanalysis at each iteration. The optimal design is formulated as a nonlinear programming problem and solved by the projected lagrangian method. The resulting solutions may be used as preliminary designs for short‐ and medium‐span highway bridges, for which cellular decks represent competitive solutions. Optimization results show that voided slab decks are more economical than box girder decks for the short span range and wide decks, and single‐cell box girders are a cost‐effective alternative for medium span range and narrow decks.

Development of Economical Low‐Volume Road Bridges

Low‐volume road bridges are currently designed according to the same specifications as urban highway bridges. Thus, many of the low‐volume bridge designs are overly conservative and uneconomical. This paper addresses this issue and proposes modifications of the existing specifications in the area of fatigue, deflection, allowable stress, composite action of timber decks, bridge width, lane loading, and the use of guardrails. All of the systems selected were combinations of prefabricated components. Jointless bridges received very high rankings and are strongly recommended for the 60‐ft and 100‐ft span ranges. A precast voided slab system and a timber deck and steel stringer system received the highest ranking on the 30‐ft span range. This study proposed a method of selecting the type of bridge system to be built in a particular area and a priority scheme to select which bridges must be replaced first. The scheme models the Federal Highway Administration (FHWA) sufficiency ranking with some of the ranking ...