scholarly journals Effect of Shear Reinforcement on Flexural Strengths of Normal Weight and Palm-Kernel Shell Reinforced Concrete Beams

2019 ◽  
Vol 8 (2) ◽  
pp. 279
Author(s):  
Lekan Makanju Olanitori ◽  
Jeremiah Ibukun Okusami

The focus of this research is to investigate the effect of shear reinforcement on flexural capacities of reinforced Normal Weight Concrete (NWC) and Palm Kernel Shell Concrete (PKSC) beams. Ten beams were cast: five from PKSC and five from NWC. The beams were with shear reinforcement spacing of 50 mm, 100 mm, 150 mm, 200 mm and without shear reinforcement respectively. The beams were loaded with a point load at beam centre, and the results showed that the flexural capacity of the beams decreases as the spacing of the shear reinforcements increases. The ultimate loads of PKSC beams were lesser than that of NWC beams by 9.0%, 7.1%, 14.5%, 21 and 26.8% for shear reinforcement spacing of 50 mm, 100 mm, 150 mm, 200 mm and for beam without shear reinforcements respectively. The deflections of the PKSC beams were greater than that of the NWC, hence the PKSC beams had more plastic rotation capacity than the NWC beams. The study shows that reinforced concrete beams produced from 20% partial replacement of crushed aggregate by PKS have the potential of being used for structural purposes in low cost buildings. Keywords: Palm Kernel Shell Concrete, Normal weight concrete, Palm kernel shell, Deflection, Shear reinforcement.

2019 ◽  
Vol 8 (2) ◽  
pp. 346
Author(s):  
Lekan Makanju Olanitori ◽  
Jeremiah Ibukun Okusami

Reduction in self-weight of Palm Kernel Shell Concrete (PKSC) over Normal Weight Concrete (NWC), reduces the amount of cement needed for construction, this is accompanied by reduction in CO2 emission associated with the production of cement: This will have reduction effect on the greenhouse, a major cause of climate change. This study carries out the comparative analysis of the strength characteristics of NWC and PKSC beams produced from four concrete mixes of 0%, 20%, 40% and 60% partial replacement of crushed granite by palm kernel shell (PKS).  From each concrete mix, two beams were cast: one with shear reinforcement of 200mm spacing, while the other one without shear reinforcement, making total of eight beams. From the study, the PKS concrete beams were 3.6%, 11.24% and 15.64% lighter than the NWC beams for 20%, 40% and 60% partial PKS replacement. The study shows that reinforced concrete beams produced from 20% and 40% partial replacement of crushed aggregate by PKS have the potential of being used for structural purposes in low cost buildings. Keywords: Palm Kernel Shell Concrete, Normal weight concrete, Palm kernel shell, Strength characteristic, Cement.


2018 ◽  
Vol 250 ◽  
pp. 03003
Author(s):  
Noor Suhaida Galip ◽  
Roslli Noor Mohamed ◽  
Ramli Abdullah

The bent-up bars have not been used as shear reinforcement in beams since the past 40 years or so. In all cases of design and construction nowadays, shear forces are resisted by vertical links only. Some complications in installing the multiple set of bent-up bars, the less opportunity to have sufficient number of bent-up bars due to small number of flexural reinforcement provided at the mid-span of the beams and also the large anchorage required for the horizontal portion of the bars beyond the upper end of the bend could be the reasons behind this. This paper presents the results of tests on five rectangular reinforced concrete beams in which the effectiveness of welded inclined bars (WIB) as shear reinforcement was studied. Two of the beams were controlled specimens, with no shear reinforcement in one, and full design vertical links in another. The other three beams were provided with three different quantities of WIB, measured in terms of area to distance ratio, Asw / S as shear reinforcement in the shear spans. All beams were tested to failure under two point loads with a shear span to effective depth ratio of 2.34, which would ensure that the failure was due to shear unless their shear capacities were larger than the flexural capacity. The performances of the beams were measured in terms of deflection, crack formation, strains in WIB and on the concrete surfaces in the shear region, ultimate loads and failure modes. The results show that WIB alone is capable of carrying the whole shear forces in the beam, and larger shear capacities are achieved with a larger quantity of WIB, and a higher grade of the bars used. The beam with WIB requires 22% less in the quantity of Asw / S compared to that with vertical links to achieve the same shear resistance. These suggest that WIB can be used as an effective system of shear reinforcement in beams.


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