scholarly journals Limit Equilibrium Method-based Shear Strength Prediction for Corroded Reinforced Concrete Beam with Inclined Bars

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1014 ◽  
Author(s):  
Yafei Ma ◽  
Baoyong Lu ◽  
Zhongzhao Guo ◽  
Lei Wang ◽  
Hailong Chen ◽  
...  
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Concrete Beam ◽  
Limit Equilibrium ◽  
Reinforced Concrete Beam ◽  
Limit Equilibrium Method ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Equilibrium Method ◽  
Diagonal Crack

Shear strength is a widely investigated parameter for reinforced concrete structures. The corrosion of reinforcement results in shear strength reduction. Corrosion has become one of the main deterioration factors in reinforced concrete beam. This paper proposes a shear strength model for beams with inclined bars based on a limit equilibrium method. The proposed model can be applied to both corroded and uncorroded reinforced concrete beams. Besides the tensile strength of longitudinal steel bars, the shear capacity provided by the concrete on the top of the diagonal crack, the tensile force of the shear steel at the diagonal crack, the degradation of the cross-sectional area and strength of the reinforcements induced by corrosion are all considered. An experimental work on two groups accelerated corroded beams was performed. Good agreements were found between the proposed theoretical predictions and experimental observations.

scholarly journals An experimental study on the shear capacity of corroded reinforced concrete beams without shear reinforcement

2021 ◽  
Vol 15 (1) ◽  
pp. 55-66
Author(s):  
Nguyen Ngoc Tan ◽  
Nguyen Trung Kien
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Accelerated Corrosion ◽  
Steel Rebar ◽  
Accelerated Corrosion Test

The effect of corrosion on the structural behavior of reinforced concrete (RC) beams without stirrups was experimentally investigated. A total of eight medium-scale RC beams were constructed without stirrups. The beams were 150 mm in width, 200 mm in depth, and 1100 mm in length. Test variables included three distinct degrees of corrosion (0%, 3.13%, 4.11%, and 4.93% by mass loss of steel rebar). Six beams were subjected to an accelerated corrosion test, while two beams served as non-corroded control beams. All beams were tested under four-point loading failure after the corrosion stage. The effect of various small degrees of corroded longitudinal reinforcements has been observed for the shear capacity. Test findings found that all tested beams had a brittle failure with tested corrosion degrees. Moreover, corroded beams that are exposed to 3% and 4% average corrosion degree reported having a larger shear capacity of approximately 7% compared to control beams. Lastly, beams with a corrosion degree of about 5% showed a decrease of 10% shear strength and a different failure mechanism with distinguished cracking patterns due to the formation of corrosion cracks along the longitudinal reinforcements. Keywords: reinforced concrete beam; reinforcement corrosion; shear strength; no stirrups.

Experimental Research on Crazing-Resistance of Inclined Section of Basalt Fiber Reinforced Concrete Beams

2014 ◽  
Vol 584-586 ◽  
pp. 899-903
Author(s):  
Wei Chen ◽  
Xiang Peng Li ◽  
Ting Ting Chen ◽  
Xiao Yang Wang ◽  
Chao Chao Ma
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Basalt Fiber ◽  
Volume Ratio ◽  
Reinforced Concrete Beam ◽  
Shear Capacity ◽  
Fiber Reinforced Concrete ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced

In order to research the influence of the shear capacity of reinforced concrete beam with the incorporation of basalt fiber, four basalt fiber reinforced concrete beams with parameters of length and volume ratio were designed and made. The fiber lengths were 12mm and 30mm, and the volume ratios were 1‰ and 2‰. The test data of basalt fiber reinforced concrete was obtained through the shear experiments and comparison with the common reinforced concrete beam. The results of the experiment show that the cracking load of the basalt fiber reinforced concrete beam increase obviously with the growing of fiber characteristic parameters, and effectively reduce the diagonal crack width.

scholarly journals Influence of coarse aggregate on the shear strength of reinforced concrete beams

2020 ◽  
Author(s):  
◽  
Hoosen Ahmed Jajbhay
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Concrete Beam ◽  
Coarse Aggregate ◽  
Concrete Beams ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Shear Reinforcement ◽  
Shear Transfer ◽  
Coarse Aggregates

Research to accurately predict the shear capacity of reinforced concrete beams without shear reinforcement has been ongoing since the early 20th century. Aggregate interlock of the coarse aggregates at the shear crack interface is one of the internal mechanisms of shear transfer and a major contributor to the shear capacity of slender beams. It is plausible, therefore, to investigate if the coarse aggregate itself influences the shear capacity of a concrete beam. The influence of the type of coarse aggregate on the shear capacity of beams without shear reinforcement was investigated in this study. From the literature study an understanding of the properties of coarse aggregates was gained, the internal mechanisms of shear transfer in reinforced concrete beams without shear reinforcement were determined, and the parameters influencing shear strength were identified. Based on this information an experimental program was designed. Eighteen reinforced concrete beams without shear reinforcement were cast. The beams were cast from three different types of coarse aggregates commonly used in the Durban area, i.e., dolerite, quartzite and tillite. For each type of coarse aggregate two variations were tested, i.e., 13 mm and 19 mm maximum aggregate sizes. For each size of coarse aggregate, three concrete strengths were tested. The beams were loaded in a beam press, by applying an increasing point load offset from midspan to induce cracking on the shorter side, until shear failure of the beam occurred. For the three concrete strengths, beams cast from dolerite had the highest shear capacity while beams cast from tillite had less shear capacity than beams cast from quartzite coarse aggregate. Furthermore, beams cast from 13 mm maximum size coarse aggregate had higher shear capacity than beams cast from 19 mm aggregate. The conclusion may be drawn that the type and size of coarse aggregate does influence the shear strength of a reinforced concrete beam without shear reinforcement.

scholarly journals Damage Evaluation in Shear-Critical Reinforced Concrete Beam using Piezoelectric Transducers as Smart Aggregates

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Constantin E. Chalioris ◽  
Nikos A. Papadopoulos ◽  
Georgia M. Angeli ◽  
Chris G. Karayannis ◽  
Asterios A. Liolios ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Shear Failure ◽  
Reinforced Concrete Beam ◽  
Piezoelectric Transducers ◽  
Reinforced Concrete Beams ◽  
Structural Safety ◽  
Shear Span ◽  
Externally Bonded ◽  
Diagonal Crack

AbstractDamage detection at early cracking stages in shear-critical reinforced concrete beams, before further deterioration and their inevitable brittle shear failure is crucial for structural safety and integrity. The effectiveness of a structural health monitoring technique using the admittance measurements of piezoelectric transducers mounted on a reinforced concrete beam without shear reinforcement is experimentally investigated. Embedded “smart aggregate” transducers and externally bonded piezoelectric patches have been placed in arrays at both shear spans of the beam. Beam were tested till total shear failure and monitored at three different states; healthy, flexural cracking and diagonal cracking. Test results showed that transducers close to the critical diagonal crack provided sound and graduated discrepancies between the admittance responses at the healthy state and thedamage levels.Damage assessment using statistical indices calculated from the measurements of all transducers was also attempted. Rational changes of the index values were obtained with respect to the increase of the damage. Admittance responses and index values of the transducers located on the shear span where the critical diagonal crack formed provided cogent evidence of damage. On the contrary, negligible indication of damage was yielded by the responses of the transducers located on the other shear span, where no diagonal cracking occurred.

Calculation of Flexural Capacity of Steel Reinforced Concrete Beams Strengthened with FRP

2009 ◽  
Vol 79-82 ◽  
pp. 1141-1144
Author(s):  
Jiong Feng Liang ◽  
Ze Ping Yang ◽  
Lan Lan Yan
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Design Method ◽  
Limit Equilibrium ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
Flexural Capacity ◽  
Steel Reinforced Concrete ◽  
First Case

Based on earlier theoretical works on RC beams ,the mechanical properties of steel reinforced concrete beams strengthened with FRP(fiber reinforce polymer) are further investigated theoretically including theirs failure mechanism and loadability. According to the design method of reinforced concrete beam strengthened with FRP, steel reinforced concrete beam strengthened with FRP mainly can have three kinds of destruction patterns: the first case is the tensile steel yield, the tensile shaped steel yield, the FRP are put off, the compressive zone’s concrete has not crushed; the second case is the tensile steel yield, the tensile shaped steel yield, the FRP are put off; the compressive zone’s concrete has crushed; the last case is the tensile steel yield, the tensile shaped steel yield, the FRP are not put off, the compressive zone’s concrete has crushed. The second case is discussed in this paper.Based on the different position of middle axle and steel, steel concrete beams strengthened with FRP include: middle axle through the steel web, and not through the steel and just in steel compression flange . Aim at these three kind of situations, the stress are analysed. According to the stress patterns of steel reinforced concrete beams strengthened with FRP and different position between neutral axis and steel, the discriminant formula of the boundary destroys and the formula of cross-section flexural capacity calculation are put forward by using limit equilibrium theory.The formula is expressed clearly, simple and easy to use.The depth of compressive region is given in view of different failure types.

Finite Element Analysis of Reinforced Concrete Beams with Transversely Prestressed Bars

2011 ◽  
Vol 368-373 ◽  
pp. 108-113
Author(s):  
Can Liu ◽  
Bo Wu ◽  
Kai Yan Xu
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Prestressed Concrete ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Shear Crack ◽  
Reinforced Concrete Beam ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Failure Loads

This paper presents a method that using inner transverse prestressing bars to enhance the shear capacity of concrete beams, which can be used in new transformer beams to decrease the sectional dimensions. Four transversely prestressed concrete beams and one ordinary reinforced concrete beam were tested. The nonlinear finite element method was applied to analyze them, and the following conclusions can be drawn: (a) The transverse prestressing bars can efficiently increase the shear capacity and failure load of the reinforced concrete beam, the improvement effect is more obvious when exerting the prestressing force on them properly. (b) On the whole, the simulated load-deflection relationships and failure loads of the five specimens agree well with the corresponding tested load-deflection relationships and failure loads. It indicated that the FE models used in this paper predict the structural behavior of the transversely prestressed concrete beams satisfactorily. (c) From the contour of first principal stress, it can be seen that the transverse prestressing bars can efficiently enhance the shear crack resistance of the reinforced concrete beams, if the area of transversely prestressing bars is almost same, the transverse bars with smaller diameter and smaller spacing will be better. It agrees well with the test results.

Experimental Study on Shear of Reinforced Concrete Beams with High Strength Rebars as Stirrups under Different Shear Span Ratios

2014 ◽  
Vol 578-579 ◽  
pp. 164-167 ◽  
Author(s):  
Peng Li ◽  
Xian Tang Zhang ◽  
Ming Ping Wang
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Concrete Beams ◽  
High Strength ◽  
Reinforced Concrete Beam ◽  
Shear Behavior ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Test Results ◽  
Shear Span

To investigate the influence of shear span ratio for the shear behavior of reinforced concrete beam with HRBF500 high strength rebars as stirrups, an experiment was carried out, which included 8 simply supported beams with HRBF500 rebars as stirrups. Under concentrated loads, the crack, deflection, strain of rebars, bearing capacity and failure mode are observed under different shear span ratios. Some comparisons are made between test results and calculated outcome. It shows that the shear span ratio has very important influent on the shear behavior of reinforced concrete beam with HRBF500 high strength bars as stirrups. Formula in code for design of concrete structures can be used to calculate its shear capacity with enough safety.

scholarly journals Influence of Steel Fiber on the Shear Strength of a Concrete Beam

2018 ◽  
Vol 4 (7) ◽  
pp. 1501 ◽  
Author(s):  
Ali Ammar Hameed ◽  
Mohannad Husain Al-Sherrawi
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Concrete Beam ◽  
Shear Failure ◽  
Steel Fiber ◽  
Concrete Beams ◽  
Shear Capacity ◽  
Steel Fibers ◽  
Reinforced Concrete Beams ◽  
Shear Reinforcement

The shear failure in a concrete beam is a brittle type of failure. The addition of steel fibers in a plain concrete mix helps to bridge and restrict the cracks formed in the brittle concrete under applied loads, and enhances the ductility of the concrete. In this research an attempt was made to investigate the behavior and the ultimate shear strength of hooked end steel fiber reinforced concrete beams without traditional shear reinforcement. Four simply-supported reinforced concrete beams with a shear span-to-depth ratio of about 3.0 were tested under two-point loading up to failure. Steel fibers volumetric fractions that used were 0.0, 0.5, 0.75 and 1.0%. Test results indicated that using 1.0% volume fraction of hooked steel fiber led to exclude shear failure and enhanced the use of steel fibers as shear reinforcement in concrete beams. The results also showed that a concrete beam with hooked steel fiber provided higher post-flexural-cracking stiffness, an increase in the shear capacity and energy absorption and an increase in the maximum concrete and steel reinforcement strains.

scholarly journals Influence of steel–concrete bond damage on the dynamic stiffness of cracked reinforced concrete beams

2018 ◽  
Vol 21 (13) ◽  
pp. 1977-1989 ◽  
Author(s):  
Tengfei Xu ◽  
Jiantao Huang ◽  
Arnaud Castel ◽  
Renda Zhao ◽  
Cheng Yang
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Natural Frequencies ◽  
Concrete Beams ◽  
Dynamic Stiffness ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
Reinforcing Bar ◽  
Sustained Loading ◽  
Inertia Model

In this article, experiments focusing at the influence of steel–concrete bond damage on the dynamic stiffness of cracked reinforced concrete beams are reported. In these experiments, the bond between concrete and reinforcing bar was damaged using appreciate flexural loads. The static stiffness of cracked reinforced concrete beam was assessed using the measured load–deflection response under cycles of loading and unloading, and the dynamic stiffness was analyzed using the measured natural frequencies with and without sustained loading. Average moment of inertia model (Castel et al. model) for cracked reinforced beams by taking into account the respective effect of bending cracks (primary cracks) and the steel–concrete bond damage (interfacial microcracks) was adopted to calculate the static load–deflection response and the natural frequencies of the tested beams. The experimental results and the comparison between measured and calculated natural frequencies show that localized steel–concrete bond damage does not influence remarkably the dynamic stiffness and the natural frequencies both with and without sustained loading applied. Castel et al. model can be used to calculate the dynamic stiffness of cracked reinforced concrete beam by neglecting the effect of interfacial microcracks.

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