scholarly journals Evaluation of the Flexural Performance and CO2 Emissions of the Voided Slab

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Seungho Cho ◽  
Seunguk Na
Keyword(s):  
Carbon Dioxide ◽  
Reinforced Concrete ◽  
Yield Strength ◽  
Performance Test ◽  
Environmental Influence ◽  
Concrete Slab ◽  
Structural Performance ◽  
Reinforcing Bars ◽  
Reinforced Concrete Slab ◽  
Flexural Performance

Reinforced concrete is regarded as one of the ideal structural materials which comprises concrete with high compressive strength and reinforcing bars with high tensile strength. However, concrete has been pointed out that it consumes a large volume of energy and emits a lot of carbon dioxide during its manufacturing. In order to lower such environmental burdens of concrete structures, a number of studies and approaches have been carried out. The voided slab is also suggested as a new method to reduce the environmental burden since voided section of the slab would use less concrete compared with the normal reinforced concrete slab. However, no studies have evaluated the CO2 emissions and environmental performance of voided slabs. The purpose of this study was to evaluate the structural performance of voided slabs and empirically corroborate their environmental influence. The flexural performance test was carried out based on the variables of the depth of slab, types of the void former materials, and the hollowness ratio. In addition, comparison of the emission of CO2 was also performed by considering the hollowness ratio and types of void former materials over the normal reinforced concrete slab. The structural performance of the voided slab was similar or slightly higher than the normal reinforced concrete slab. The yield strength of specimens was increased approximately 10∼30% over the anticipated yield strength. Based on this result, it is considered that the voided slab would be sufficient to structural performance and beneficial to plane planning in buildings. In general, it is considered that the voided slab would be beneficial to both structural and environmental aspects. However, the test results in this research showed that the voided slab would emit more carbon dioxide emissions compared to the normal reinforced concrete slab. The main source of more CO2 emissions in the voided slab was the anchoring materials. In this research, wires were used to fix the void former materials to the reinforcing bars. In order for the voided slab to become a more eco-friendly and sustainable material, new anchoring methods such as use of recycled materials, new void former materials without anchoring, or other eco-friendly materials should be applied to reduce the emission of CO2.

Structural Performance of Biaxial Geogrid Reinforced Concrete Slab

2021 ◽  
Author(s):  
K. RajeshKumar ◽  
P. O. Awoyera ◽  
G. Shyamala ◽  
Vinod Kumar ◽  
N. Gurumoorthy ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Structural Performance ◽  
Reinforced Concrete Slab

scholarly journals Structural performance assessment of reinforced concrete flat slab-edge column connections under the effects of outward eccentricity

2015 ◽  
Vol 8 (2) ◽  
pp. 164-195
Author(s):  
N. G. B. Albuquerque ◽  
G. S. S. A. Melo
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Concrete Slab ◽  
Bending Moment ◽  
Structural Performance ◽  
Structural Behaviour ◽  
Reinforced Concrete Slab ◽  
Specific Test ◽  
Flat Slabs ◽  
Vertical Displacements

Although several advantages - either constructive or architectural - are assigned to flat slabs, the continuity between consecutive spans in multifloor buildings may turn slab-column connections into a critical region, due to the limited contact between both elements. When transferring moments caused by horizontal and/or vertical eccentric loads are present, these effects are even more pronounced on external panels. Specific studies on the effects of outward eccentricities are still rather scarce, although it is recognized that the codes, in general, are concerned with eventually meeting all potential cases, seeking to improve safety structural performance. Some current recommendations are based on considerable extrapolations, whose theory was originally developed for cases of asymmetric loading at internal connections and need to be consolidated with specific test data. Thus, to investigate the structural behaviour of slabs-edge columns connections, four specimens were tested, reproducing a 2,350 mm x 1,700 mm portion of a 180 mm thick reinforced concrete slab adjacent to a 300 mm x 300 mm cross section squared edge column, with a projection at the base for the imposition of eccentricities. The position of the support under the column has determined the eccentricity, defining in physical terms the interaction between bending moment and shear force, as follows: 300 mm (inward), centred (reference) and 300 mm and 400 mm (outward). Experimental results allowed to comparatively assess the performance of the specimens relating the strain measurements in steel and concrete, vertical displacements, rotations, failure mode and ultimate loads of the slabs. Results indicate that the influence of transferring moments on failure modes is much more pronounced than the shear action in the case of edge connections subjected to outward eccentricities.

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

2019 ◽  
Vol 9 (20) ◽  
pp. 4333 ◽  
Author(s):  
Inkwan Paik ◽  
Seunguk Na
Keyword(s):  
Carbon Dioxide ◽  
Global Warming ◽  
Flat Plate ◽  
Construction Industry ◽  
Co2 Emissions ◽  
Carbon Dioxide Emissions ◽  
Building Materials ◽  
Concrete Slab ◽  
Reinforcing Bars ◽  
Reinforced Concrete Slab

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.

scholarly journals 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

2019 ◽  
Vol 11 (13) ◽  
pp. 3571 ◽  
Author(s):  
Inkwan Paik ◽  
Seunguk Na
Keyword(s):  
Carbon Dioxide ◽  
Life Cycle ◽  
Reinforced Concrete ◽  
South Korea ◽  
Construction Industry ◽  
Carbon Dioxide Emissions ◽  
Building Materials ◽  
Concrete Slab ◽  
Reinforced Concrete Slab

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.

Assessment of CSA A23.3 structural integrity requirements for two-way slabs

2012 ◽  
Vol 39 (4) ◽  
pp. 351-361 ◽  
Author(s):  
Farshad Habibi ◽  
Erin Redl ◽  
Michael Egberts ◽  
William D. Cook ◽  
Denis Mitchell
Keyword(s):  
Reinforced Concrete ◽  
Structural Integrity ◽  
Concrete Slab ◽  
Punching Shear ◽  
Slab Thickness ◽  
Test Results ◽  
Reinforcing Bars ◽  
Reasonable Estimate ◽  
Reinforced Concrete Slab ◽  
Rectangular Columns

This paper investigates the post-punching behaviour of reinforced concrete slab–column connections with a goal of providing adequate structural integrity reinforcement. The test results of seven interior slab–column connections are presented. A study was made of the effects of slab thickness, length of structural integrity reinforcing bars, distribution of structural integrity reinforcement in slabs with rectangular columns, and the placement of structural integrity reinforcement in slabs with drop panels. Results from this test series and other researchers were compared with predictions using the CSA A23.3-04 design equations for both punching shear and post-punching resistance. The test results demonstrated that the provision of structural integrity reinforcement in accordance with the requirements of CSA A23.3-04 resulted in significant post-punching resistance and the design equations provide a reasonable estimate of this resistance.

Dimension and Frequency Profiles of Concrete Highway Bridges in New Madrid Region of Southeastern Missouri

1997 ◽  
Vol 1594 (1) ◽  
pp. 84-93 ◽  
Author(s):  
Ralph Alan Dusseau
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Highway Bridges ◽  
Ambient Vibration ◽  
Earthquake Hazards ◽  
Empirical Formulas ◽  
Reinforced Concrete Slab ◽  
Box Girder ◽  
Bridge Spans ◽  
New Madrid

The results of a study funded by the U.S. Geological Survey as part of the National Earthquake Hazards Reduction Program are presented. The first objective of this study was the development of a database for all 211 highway bridges along I-55 in the New Madrid region of southeastern Missouri. Profiles for five key dimension parameters (which are stored in the database) were developed, and the results for concrete highway bridges are presented. The second objective was to perform field ambient vibration analyses on 25 typical highway bridge spans along the I-55 corridor to determine the fundamental vertical and lateral frequencies of the bridge spans measured. These 25 spans included six reinforced concrete slab spans and two reinforced concrete box-girder spans. The third objective was to use these bridge frequency results in conjunction with the dimension parameters stored in the database to develop empirical formulas for estimating bridge fundamental natural frequencies. These formulas were applied to all 211 Interstate highway bridges in southeastern Missouri. Profiles for both fundamental vertical and lateral frequencies were then developed, and the results for concrete highway bridges are presented.

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