scholarly journals Influence of PVC Fiber Reinforcement on Shear Strength in Concrete Beams

2019 ◽  
Vol 7 (1) ◽  
pp. 34-43
Author(s):  
Kadhim Zuboon Nasser ◽  
Ali Abdulhasan Khalaf ◽  
Fadhil K. Idan
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Volume Fraction ◽  
Concrete Structures ◽  
Fiber Reinforcement ◽  
Steel Reinforcement ◽  
Reinforced Concrete Beams ◽  
Shear Reinforcement ◽  
Time Service ◽  
Before And After

This study adopted the investigation of the effect of a material that can be used as an alternative to steel reinforcement of shear in reinforced concrete beams, as the most susceptible to corrosion to which reduces the time service of the concrete structures and increase the maintenance costs is the steel reinforcement of shear for the closeness of surface of concrete. Therefor non-corroding material is needful for concrete structures and PVC fiber reinforcement is chosen. Experimentally nine reinforced concrete beams have been tested to determine the effect of PVC fiber reinforcement on the concrete beam resistance load, the load of cracks, deflection achieved and distribution with dimension of cracks. Three volume fraction ratios were taken for PVC fiber reinforcement (0, 0.25 and 0.5), which were identical to the shear reinforcement used in this research (0,0.29 and 0.54). All the concrete beams were tested with in on one program by applied a center load from the top in the middle to the failure load and the results were impressive. The specimens containing the PVC fiber reinforcement percentages achieved a remarkable increase in the crack and ultimate load of the concrete beams before and after cracks with direct effect in changing the failure type. While the deflection achieved due to the increase in PVC fiber percentage is more than the allowable deflection in the ACI Code equations of the reinforced concrete beams and more of these if the use of PVC fiber and steel reinforcement of shear together. A smaller measurement of the maximum cracks width was achieved by using advanced percentages of PVC fiber and shear reinforcement (0.5 and 0.54) respectively.

scholarly journals THE PROPERTIES OF PITTING CORROSION OF STEEL REINFORCEMENT OF REINFORCED CONCRETE BEAMS

2017 ◽  
Vol 2 (3) ◽  
pp. 32-36
Author(s):  
Дронов ◽  
Andrey Dronov
Keyword(s):  
Reinforced Concrete ◽  
Pitting Corrosion ◽  
Concrete Beams ◽  
Concrete Structures ◽  
Steel Reinforcement ◽  
Reinforced Concrete Beams ◽  
Reinforced Concrete Structures ◽  
Damage Distribution ◽  
Chloride Environment ◽  
Corrosion Of Steel

Two types of steel reinforcement depassivation process: carbonation of concrete and chloride penetration are considered in the article. The comparison between the corrosion due to carbonation of concrete and the chloride-induced corrosion was carried out. It was found out, that chlorides induced corrosion is potentially more dangerous than that resulting from carbonation. Method of durable tests of reinforced concrete structures under the action of the gravitational load and the corrosive chloride environment is described in the article. The results of experimental research on reinforced concrete structures with corrosive damages to steel reinforcement are given in the article. The properties of corrosion cracking in the case of the pitting corrosion were determined. The character of corrosive damage distribution along the reinforcement bars and its effect on the strength of reinforced concrete beams were determined.

BEHAVIOR OF CORRODED RC BEAMS WITHOUT STIRRUPS REPAIRED WITH CFRP SHEETS

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Abdullah Al-Saidy ◽  
Sherif El-Gamal ◽  
Khlaifa Al-Jabri ◽  
Bilal Waris
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Strength Loss ◽  
Steel Reinforcement ◽  
Reinforced Concrete Beams ◽  
Experimental Program ◽  
Shear Reinforcement ◽  
Accelerated Corrosion ◽  
Cfrp Sheets ◽  
Externally Bonded

In reinforced concrete structures located in hot and humid areas, steel reinforcement is generally vulnerable to deterioration due to corrosion. Corrosion of reinforcement in many cases is considered the main cause of concrete structures deterioration, which in turn requires large budgets for repair and maintenance. This paper presents the experimental results of damaged/repaired reinforced concrete beams. The experimental program consisted of testing reinforced concrete rectangular beam specimen’s with/without shear reinforcement and exposed to accelerated corrosion of the longitudinal steel reinforcement on the tension side. Bonding external U-shaped CFRP sheets to restore the strength loss due to corrosion repaired corroded beams without shear reinforcement. The test results showed that corroded beams without stirrups failed in a brittle manner with drop in maximum deflection at failure of approximately 60% compared to the uncorroded beam. Corroded beams with stirrups lost some strength, but failed in ductile manner. Using externally bonded U-shaped CFRP sheets restored the ductility of corroded beams without stirrups and prevented bond failure at the steel concrete interface due to the absence of internal stirrups.

scholarly journals RETROFITTING AND DACTILITY OF REINFORCED CONCRETE BEAMS USING AN EXTERNAL REINFORCEMENT METHOD

2019 ◽  
Vol 3 (2) ◽  
pp. 135
Author(s):  
Novita Ike Triyuliani ◽  
Sri Murni Dewi ◽  
Lilya Susanti
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Load ◽  
Concrete Beams ◽  
Concrete Block ◽  
Steel Reinforcement ◽  
Reinforced Concrete Beams ◽  
Building Structures ◽  
Average Increase ◽  
External Reinforcement ◽  
Strength And Ductility

The innovations strengthening building structures are important topics. Failure in structures such as beams and columns due to time, re-functions of a building, even initial design errors that are weak or lack the safety factor of a building structure. External reinforced concrete beams are one of the beams currently being developed. It is a concrete block with reinforcement of steel reinforcement on the outer (external) of the beam. This study aims to determine the index of increasing beam strength and ductility after retrofitting external steel reinforcement, which has the dimension of beams 15 x 15 x 100 cm, repeating 12 pcs, with external reinforcement each 6 pcs 2Ø6 and 3Ø6. The results from this study are an increasing the index of beam flexural strength after retrofit with external steel reinforcement. Meanwhile, beams after retrofit with 2Ø6 external steel have an average increase index of 1.25 and 1.21 while for external steel 3Ø6 are 1.29 and 1.60 respectively. The ductility depends on the value of ultimate load and maximum deflection that occurs, where the ductility value for the comparison of each specimen experiences a reduction in the average ductility value with 2Ø6 external steel which is 37.74% and 70.95% while with 3Ø6 external steel is 61,65% and 60.62%. Berbagai inovasi upaya peningkatan kekuatan struktur bangunan telah menjadi bahasan yang penting. Kegagalan pada struktur seperti balok dan kolom karena umur, alih fungsi suatu bangunan, bahkan kesalahan desain awal yang lemah atau kurang memenuhi faktor keamanan suatu struktur bangunan. Balok beton bertulangan eksternal adalah salah satu balok yang sedang dikembangkan pada saat ini, yaitu balok beton dengan perkuatan tulangan baja di sisi terluar (eksternal). Penelitian ini bertujuan untuk mengetahui indeks peningkatan kekuatan balok dan daktilitas setelah dilakukan perbaikan menggunakan tulangan baja eksternal, dengan dimensi balok 15 × 15 × 100 cm berulang 12 buah, penambahan tulangan baja eksternal masingmasing 6 buah 2Ø6 dan 3Ø6. Hasil yang didapat dari penelitian ini adalah indeks peningkatan kekuatan lentur balok setelah dilakukan perbaikan menggunakan tulangan baja eksternal. Dimana balok setelah dilakukan perbaikan dengan baja eksternal 2Ø6 memiliki indeks peningkatan rata-rata 1,25 dan 1,21 sedangkan untuk baja eksternal 3Ø6 masing-masing 1,29 dan 1,60. Daktilitas tergantung dari nilai beban ultimit dan lendutan maksimum yang terjadi, dimana nilai daktilitas untuk perbandingan tiap benda uji mengalami reduksi nilai daktilitas rata-rata dengan baja eksternal 2Ø6 yaitu sebesar 37,74% dan 70,95% sedangkan dengan baja eksternal 3Ø6 sebesar 61,65% dan 60,62%.

scholarly journals DUCTILITY RESPONSE OF HYBRID FIBRE REINFORCED CONCRETE BEAMS

2018 ◽  
pp. 174-179 ◽  
Author(s):  
Eswari Natarajan
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Load ◽  
Concrete Beams ◽  
Volume Fraction ◽  
Fibre Volume ◽  
Reinforced Concrete Beams ◽  
Fibre Reinforced Concrete ◽  
Hybrid Fibre ◽  
Service Load ◽  
Strength And Ductility

Abstract: The effect of fibre content on the Strength and ductility behaviour of hybrid fibre reinforced concrete (HFRC) beams having different fibre volume fractions was investigated. The parameters of this investigation included service load, ultimate load, service load deflection, ultimate load deflection, crack width, deflection ductility and energy ductility. The fibre volume fraction (Vf) ranged from 0.0 to 2.0 percent. Steel and polyolefin fibres were combined in different proportions and their impact on the above parameters was studied. The ductile response of hybrid fibre reinforced concrete beams was compared with that of control beam. The test results show that addition of 2.0 percent by volume of hybrid fibres improve the strength and ductility appreciably. Empirical expressions for predicting the strength and ductility of hybrid fibre reinforced concrete (HFRC) are proposed based on regression analysis. A close agreement has been obtained between the predicted and experimental results.

scholarly journals Shear resistance of welded inclined bars in rectangular reinforced concrete beams

2018 ◽  
Vol 250 ◽  
pp. 03003
Author(s):  
Noor Suhaida Galip ◽  
Roslli Noor Mohamed ◽  
Ramli Abdullah
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Concrete Beams ◽  
Shear Resistance ◽  
Reinforced Concrete Beams ◽  
Shear Reinforcement ◽  
Shear Forces ◽  
Distance Ratio ◽  
Effective System ◽  
Horizontal Portion

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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