Laboratory Fast Corrosion Test of Plain Steel Bars in Concrete Beams

2012 ◽  
Vol 535-537 ◽  
pp. 1803-1806
Author(s):  
Shun Bo Zhao ◽  
Peng Bing Hou ◽  
Fu Lai Qu
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Numerical Models ◽  
Concrete Strength ◽  
Reinforced Concrete Beams ◽  
Uniform Corrosion ◽  
Pure Bending ◽  
Accelerated Corrosion ◽  
Steel Bars ◽  
Bending Length

An experimental study was carried out to examine the non-uniform corrosion of plain steel bars in reinforced concrete beams partially placed in 5% sodium chloride solution under conditions of accelerated corrosion. 4 reinforced concrete beams with different concrete strength were made. The crack distributions of the beams due to pre-loads and expansion of corrosion product, and the sectional corrosion characteristics of plain steel bars are described in detail. The sectional area loss relating to mass loss and change along pure bending length of the beams are discussed. These can be used as the basis of test for further studies to build the numerical models of serviceability of corroded reinforced concrete beams.

scholarly journals Influence of the percentage of reinforcement by unstressed rebar on the deformability of pre-stressed RC beams

2021 ◽  
Vol 27 (3) ◽  
pp. 212-216
Author(s):  
Yaroslav Blikharskyy ◽  
Jacek Selejdak ◽  
Taras Bobalo ◽  
Roman Khmil ◽  
Mykhailo Volynets
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Bending Moment ◽  
Reinforced Concrete Beams ◽  
Practical Significance ◽  
Pure Bending ◽  
Static Loads ◽  
Steel Bars ◽  
Periodic Profile

Abstract This article presents the materials of deformability studies of pre-stressed steel-concrete beams reinforced with a package of reinforcement with different ratio of tape and rebar in the pure bending moment zone. The aim of the research was determination of the reinforcement percentage influence, for pre-stressed reinforced concrete beams reinforced with a package of reinforcement on their deformability. Also, the aim was to evaluate the effectiveness of using pre-stressed rebar in combined reinforcement. The practical significance of the experimental research is to study the deformability in pre-stressed bending elements with external tape and rebar reinforcement, taking into account the influence of different ratios of reinforcement areas within the combined reinforcement and development of proposals for such structures` calculation and design. The scientific novelty of the research is in obtaining the deformability characteristics of reinforced concrete beams reinforced with a package of reinforcement (tape and steel bars with periodic profile) with different ratios in the case of static loads` action.

scholarly journals EXPERIMENTAL LOAD-DRIFT RELATIONS OF CONCRETE BEAM REINFORCED AND CONFINED WITH HIGH-STRENGTH STEEL BARS UNDER REVERSED CYCLIC LOADING

2021 ◽  
Vol 11 (4) ◽  
pp. 56-69
Author(s):  
Retno Anggraini ◽  
Tavio Tavio ◽  
Gusti Putu Raka ◽  
Agustiar Agustiar
Keyword(s):  
Reinforced Concrete ◽  
High Strength Steel ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Concrete Strength ◽  
High Strength ◽  
Reinforced Concrete Beams ◽  
Test Results ◽  
Steel Bars ◽  
Normal Strength

High-strength steel bars have different characteristics from normal-strength steel bars. Thus, the use of high-strength steel bars still needs to be investigated further before it can be used confidently in concrete structures. In the design, a reinforced concrete beam should also have enough ductility besides its loading capacity. One of the indicators identifies that a structure has sufficient ductility is its ability to maintain the load steadily due to progressive deformation. This paper presents the test results of three reinforced concrete beams designed with concrete strength (fc) of 30 MPa. Two different yield strengths (fy) of longitudinal and transverse reinforcements were used, namely, 420 and 550 MPa. The cross-sectional dimensions of the beams were 200  300 mm with a total span of 2000 mm and a rigid stub at the midspan. The beams were simply supported by double rollers at their tops and bottoms. These special supports were located at both ends of the beams. The load applied at the midspan of the beam through the rigid stub with the displacement control. The loading pattern protocol by the drift was set from 0 to 5.5 percent. Based on the test results, it can be seen that the beams with high-strength steel bars could achieve a higher load capacity than the beams with normal-strength steel bars. On the other hand, the beams with high-strength steel bars produced lower deflection than the beams with normal-strength steel bars. Furthermore, it can be concluded that all the beams could withstand the minimum required of 3.5 percent. None of the beams indicated brittle failures. All of the beams could survived until the end of the cycles at a drift of 5.5 percent. This condition indicates that the reinforced concrete beams with higher-strength reinforcement (fy of 550 MPa) could also maintain their load capacities under large deformation beyond the first yielding of the longitudinal steel bars.

scholarly journals Numerical Sensing of Plastic Hinge Regions in Concrete Beams with Hybrid (FRP and Steel) Bars

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3255 ◽  
Author(s):  
Fang Yuan ◽  
Mengcheng Chen
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Plastic Hinge ◽  
Reinforcement Ratio ◽  
Reinforced Concrete Beams ◽  
Concrete Members ◽  
Steel Bars ◽  
Hybrid Reinforcement ◽  
Steel Hardening

Fibre-reinforced polymer (FRP)-reinforced concrete members exhibit low ductility due to the linear-elastic behaviour of FRP materials. Concrete members reinforced by hybrid FRP–steel bars can improve strength and ductility simultaneously. In this study, the plastic hinge problem of hybrid FRP–steel reinforced concrete beams was numerically assessed through finite element analysis (FEA). Firstly, a finite element model was proposed to validate the numerical method by comparing the simulation results with the test results. Then, three plastic hinge regions—the rebar yielding zone, concrete crushing zone, and curvature localisation zone—of the hybrid reinforced concrete beams were analysed in detail. Finally, the effects of the main parameters, including the beam aspect ratio, concrete grade, steel yield strength, steel reinforcement ratio, steel hardening modulus, and FRP elastic modulus on the lengths of the three plastic zones, were systematically evaluated through parametric studies. It is determined that the hybrid reinforcement ratio exerts a significant effect on the plastic hinge lengths. The larger the hybrid reinforcement ratio, the larger is the extent of the rebar yielding zone and curvature localisation zone. It is also determined that the beam aspect ratio, concrete compressive strength, and steel hardening ratio exert significant positive effects on the length of the rebar yielding zone.

scholarly journals Reliability of beams designed in accordance with Brazilian codes

2014 ◽  
Vol 7 (5) ◽  
pp. 723-746 ◽  
Author(s):  
D. M. Santos ◽  
F. R. Stucchi ◽  
A. T. Beck
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Composite Beams ◽  
Reinforced Concrete Beams ◽  
Steel Beams ◽  
Structural Elements ◽  
Pure Bending ◽  
Design Standards ◽  
Limit Values ◽  
Relative Safety

This paper presents an investigation on the safety of structural elements submitted to pure bending, produced in reinforced concrete, in steel and steel-concrete composites, and designed according to Brazilian codes NBR8681:2003, NBR6118:2007 and NBR8800:2008. The study allows a comparison of the relative safety of beams produced with these materials and designed using these codes. Comparative studies between the performances of different materials are difficult to find in the published literature. The present study shows that reliability indexes for reinforced concrete beams are satisfactory; however, results for steel beams are below limit values established in international design standards. Reliability indexes found herein for steel-concrete composite beams are intermediate to concrete and steel beams.

scholarly journals Study of the reinforcement of structure members by polypropylene fibres waste

2018 ◽  
Vol 149 ◽  
pp. 01022 ◽  
Author(s):  
Khadra Bendjillali ◽  
Mohamed Chemrouk
Keyword(s):  
Reinforced Concrete ◽  
Significant Contribution ◽  
Concrete Beams ◽  
Average Diameter ◽  
Concrete Surface ◽  
Point Of View ◽  
Reinforced Concrete Beams ◽  
Polypropylene Fibres ◽  
Steel Bars ◽  
Material Durability

The valorisation of industrial waste in the field of construction became a very interesting axis of research from scientific, economic and environmental point of view. We have conducted this work to study the effect of the addition of polypropylene fibres waste on the mechanical behaviour of reinforced concrete beams subjected to a simple flexural loading, with and without transversal reinforcement. The used fibres are coming from the waste of the fabrication of domestic brushes and sweeps; they have an average diameter of 0.47 mm and a length between 40 and 60 mm. Two weight dosages of fibres are used, 0.25 and 0.5 %. The experimental results showed that the incorporation of polypropylene fibres waste into the concrete affects negatively its workability, but its flexural and compressive strength are improved. The fibers have presented a significant contribution on the shear behavior and the cracking of beams, particularly in absence of transversal bars. The waste used in this work as fibrous reinforcement has not only increased the ductility of reinforced concrete beams, but it have also provided a perfect cracking distribution on the concrete surface and it has participated in a considerable way in the reduction of cracks number and dimensions, which allows to ensure the material durability and then the structure longevity. The reinforcement of concrete beams with 0.5 % of polypropylene fibers waste with a minimal steel bars can ensure an excellent mechanical behavior in shear, as in flexion.

Shear strength of disturbed regions with corroded stirrups in reinforced concrete beams

2010 ◽  
Vol 37 (8) ◽  
pp. 1045-1056 ◽  
Author(s):  
Christopher Suffern ◽  
Ahmed El-Sayed ◽  
Khaled Soudki
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Corrosion Damage ◽  
Reinforced Concrete Beams ◽  
Test Results ◽  
Accelerated Corrosion ◽  
Damage Level ◽  
Three Point Bending ◽  
Shear Span

This paper reports experimental data on the structural performance of disturbed regions in reinforced concrete beams with corrosion damage to the embedded steel stirrups. A total of 15 reinforced concrete beams were constructed and tested. The test beams were 350 mm deep, 125 mm wide, and 1850 mm long. The beams were tested in three-point bending under a simply supported span of 1500 mm. Nine beams had the embedded stirrups subjected to accelerated corrosion. The test variables were the corrosion damage level and the shear span-to-depth ratio. The test results indicated that the corroded beams exhibited reduced shear strength in comparison to the uncorroded control specimens. The shear strength reduction was up to 53%. Furthermore, the reduction in shear strength due to the corrosion was found to be greater at smaller shear span-to-depth ratios.

scholarly journals Effect of Plastering Layer on Corrosion Resistances of Reinforced Concrete Beams

2019 ◽  
Vol 9 (1) ◽  
pp. 1390-1393
Keyword(s):  
Corrosion Resistance ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Point Load ◽  
Reinforced Concrete Beams ◽  
Experimental Program ◽  
Structural Elements ◽  
Accelerated Corrosion ◽  
Total Mass Loss ◽  
Load Arrangement

Reinforced concrete structures are subjected to deterioration due to many factors such as corrosion of reinforcing steel. Ultimate strengths of structural elements can be greatly affected by these deteriorating factors. There are numerous methods and techniques used to protect these structural elements. The mortar layer (Plastering) is considered the first defense line against all the deteriorating factors. The main goal of this research is to investigate to what extent the plastering layer can protect reinforced concrete beams against corrosion. The aim of the experimental program is to study the effect of plastering layer on corrosion resistance of reinforced concrete beams. Four reinforced concrete beams (1002001100 mms) and four Lollypop specimens (cylinders 100200 mms) were tested and described as follows: • A beam and a lollypop specimen without any plastering layer (control). • A beam and a lollypop specimen with traditional plastering layer (cement + sand + water). • A beam and a lollypop specimen with modified plastering (traditional plastering + waterproof admixtures). • A beam and a lollypop specimen with painted and modified plastering layer (traditional plastering + waterproof admixtures + external waterproof paint). These eight specimens were subjected to corrosion using accelerated corrosion technique, after that the four beams were tested in flexure under three point load arrangement while the four lollypops were used to calculate the total mass loss due to accelerated corrosion. The test results were used to figure out the effect of plastering layer on corrosion resistance of RC beams.

scholarly journals Seismic Behaviors of Concrete Beams Reinforced with Steel-FRP Composite Bars under Quasi-Static Loading

2018 ◽  
Vol 8 (10) ◽  
pp. 1913 ◽  
Author(s):  
Tong-Liang Xiao ◽  
Hong-Xing Qiu ◽  
Jia-Le Li
Keyword(s):  
Reinforced Concrete ◽  
Seismic Performance ◽  
Concrete Beams ◽  
Concrete Strength ◽  
Reinforced Concrete Beams ◽  
Ultimate Capacity ◽  
Shear Span ◽  
Frp Composite ◽  
Drift Ratio ◽  
Seismic Behaviors

Steel-fiber reinforced polymer (FRP) composite bar (SFCB) is a new composite material with good corrosion resistance and designable post-yield stiffness. Substitution of steel bar with SFCB can greatly increase the durability and ultimate capacity associated with seismic performance. First, the method and main results of the experiment are briefly introduced, then a simplified constitutive model of composite bar material was applied to simulate the seismic behaviors of the concrete beams reinforced with SFCBs by fiber element modeling. The simulation results were found to be in good agreement with test results, indicating that the finite element model is reasonable and accurate in simulating the seismic behaviors of beams reinforced with SFCB. Based on the numerical simulation method, a parametric study was then conducted. The main variable parameters were the FRP type in composite bars (i.e., basalt, carbon FRP and E-glass FRP), the concrete strength, basalt FRP (BFRP) content in SFCBs and shear span ratio. Seismic behaviors such as load-displacement pushover curves, seismic ultimate capacity and its corresponding drift ratio of the SFCBs reinforced concrete beams were also evaluated. The results showed that (1) the fiber type of the composite bar had a great impact on the mechanical properties of the beam, among which the beam reinforced with BFRP composite bar has higher seismic ultimate capacity and better ductility. With the increase of the fiber bundle in the composite bar, the post-yield stiffness and ultimate capacity of the component increase and the ductility is better; (2) at the pre-yield stage, concrete strength has little influence on the seismic performance of concrete beams while after yielding, the seismic ultimate capacity and post-yielding stiffness of specimens increased slowly with the increase in concrete strength, however, the ductility was reduced accordingly; (3) as the shear span ratio of beams increased from 3.5 to 5.5, the seismic ultimate capacity decreased gradually while the ultimate drift ratio increased by more than 50%. Through judicious setting of the fiber content and shear span ratio of the composite bar reinforced concrete beam, concrete beams reinforced with composite bars can have good ductility while maintaining high seismic ultimate capacity.

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