Behavior Of RC Beams Research Articles

Effect of Magnetic Water on Behavior of RC Beams with Ordinary Portland cement and Raid Hardening Portland Cement

Effect of Magnetic Water on Behavior of RC Beams with Ordinary Portland cement and Raid Hardening Portland Cement

고강도 스터럽으로 설계된 RC 보의 비틀림 거동에 관한 실험 연구

고강도 스터럽으로 설계된 RC 보의 비틀림 거동에 관한 실험 연구

Experimental Study on Torsional Behavior of RC Beam with High Strength Stirrup

Experimental Study on Torsional Behavior of RC Beam with High Strength Stirrup

Experimental study on the seismic behaviour of RC beams with standing and hanging walls

Recently, earthquake damage to non-structural walls has become one of the important issues in Japan. Some buildings were demolished after the 2011 Tohoku Earthquake due to damage of non-structural walls without any significant damage in structural members. After that, several projects were launched to develop a new method to take into account the effect of non-structural walls (hanging, standing, and wing walls). In this paper, experimental test results for beam-column joints with non-structural walls are presented. The objectives of the tests were to investigate the equivalent length and hinge location of beams with hanging and standing walls. The results showed that the yield hinge located at the surface of the wing walls and beam-column joint should be modelled as rigid to estimate the deformation of the beams, regardless of the thickness and height of the wall. A tri-linear modelling method for beams with hanging and standing walls was also proposed, and its applicability was confirmed with the test results.

Modelling of RC Beams Strengthened with Basalt Reinforced Concrete

An analytical model was developed to predict the response behaviour of RC beam strengthened with basalt reinforced concrete. The model was based on the internal forces, strains, and stresses in the cross- section of the strengthened composite beam. It is observed that the analytical results are in good agreement with experimental results. Further, non linear finite element analyses was carried out on RC beams strengthened with basalt reinforced concrete. Geometric modelling, material modelling and interaction between different materials were discussed in detail. Displacement controlled analyses were performed and the response behaviour was validated by comparing with the respective experimental results. Parametric studies were conducted on RC beams strengthened with basalt reinforced concrete and the effect of volume fraction towards enhancing the flexural behaviour of RC beams was studied in detail.

Behavior of RC beams with tension lap splices confined with transverse reinforcement using different types of concrete under pure bending

Many research studies have been carried out on the different parameters affecting the bond strength of tension lap splices in RC beams but limited attention has been given to the effect of using transverse reinforcement along the splice length. The first part of this research is an experimental program which consisted of sixteen reinforced concrete beams tested at the concrete laboratory of the Faculty of Engineering, Cairo University. The parameters under study herein are the diameter of the transverse reinforcement as well as its shape and distribution while using three different types of concrete. The beams were all simply supported with 1800mmspan and 150×250mm cross section. The tensile steel was spliced in the constant moment zone. The second part of the research consisted of an analytical study to enhance the understanding of the topic of this research. Three-dimensional nonlinear finite element analysis was carried with the help of the well-known finite element software; ABAQUS. The concrete damaged plasticity model is selected at this study because it is capable of representing the complete inelastic behavior of concrete both in tension and in compression including damage characteristics. The analytical and experimental results were compared and contrasted. Good agreement was obtained.

Effect of Elevated Temperature on Flexural Behavior of RC Beams with NSM CFRP

The strengthening of RC structures with fiber reinforced polymer (FRP) materials has demonstrated enormous potential as a repairing material. However, their thermal and mechanical behaviors after exposure to elevated temperature remain an obstacle due to FRP’s sensitivity to high temperatures as compared with order structural materials. In this paper an experimental works was conducted to study the behavior of RC beam with NSM CFRP with different adhesive materials exposed to elevated temperature of 550°C for different periods of time and cooling schemes. In this experimental study 6 beams were cast, one beam (BN) was not exposed to elevated temperature as a control beam and the remaining beams were exposed to elevated temperature. These beams were tested under four-point loading. The effect of variables was studied in terms of ultimate failure load, maximum deflection and failure mode. From the test results, it could be concluded that ready-mix mortar could be as an alternative adhesive material. The ultimate load-carrying capacity of the RC beam was reduced for longer duration of elevated temperature.

Impact Resistant Behavior of RC Beam Damaged by Freeze-Thaw Action

In this study, in order to investigate the impact resistant behavior of RC beams damaged by freeze-thaw action, falling-weight impact tests for RC beams were conducted taking with/without frost damage as variable. The RC beam used in this study has been damaged by accelerated freeze-thaw cycling. From this experiment, following results were obtained: 1) Elastic modulus and compressive strength of the concrete were decreased due to freeze-thaw action; 2) In the case of damaged beam, many fine cracks were occurred in small input energy; and 3) Deflections of damaged beam was larger than that of non-damaged beam at the same weight-falling height.

Behaviour of RC Beams with non-bonded flexural reinforcement: A numerical experiment

The present work is concerned with a numerical investigation of the behaviour of reinforced-concrete beams with non-bonded flexural tension reinforcement. The numerically-established behaviour of such beams with and without transverse reinforcement is compared with its counterpart of similar beams with bonded reinforcement. From the comparison, it is found that the development of bond anywhere within the shear span inevitably leads to inclined cracking which is the cause of 'shear' failure. On the other hand, the lack of bond within the shear span of the beams is found, not only to prevent cracking within the shear span, but, also, to lead to a flexural type of failure preceded by the formation of horizontal splitting of concrete in the compressive zone. It is also found that delaying the extension of horizontal splitting through the provision of transverse reinforcement in the beam mid span can lead to flexural failure after yielding of the tension reinforcement. Yielding of the tension reinforcement before the horizontal splitting of the compressive zone may also be achieved by reducing the amount of the latter reinforcement.

An Experimental Study on Strengthening of Reinforced Concrete Beam using Glass Fiber Reinforced Polymer Composites

Objective: This work deals with the experimental investigation on the study the effect of glass fiber reinforced polymer composite sheets in RC beam. Methods/Statistical analysis: An experimental setup is placed the specimens on the loading frame for flexure and shear behaviour of RC beams. Findings: Determining the load, deflection and failure mode of each beams and their results (beam F2, F3) are compared with controlled concrete beam (F1). The beam F2 has initial flexural cracks appeared at higher load than beam F1.The ultimate load carrying capacity of beam F2 is 35%, which is higher than beam F1. Applications/Improvements: The beam with GFRP sheets upto neutral axis of beam, which is increasing the ultimate load carrying capacity.

Displacement‐based simulation of time‐dependent behaviour of RC beams with prestressed FRP or steel tendons

AbstractPredicting the time‐dependent behaviour of prestressed concrete (PC) beams is crucial as time effects under serviceability loading can result in a critical loss of prestress. The conventional technique using moment–curvature (M/χ) to simulate the behaviour of PC beams is based on the Euler‐Bernoulli corollary of a linear strain profile in which all deformations are accommodated through changes in the material strain, i.e. it is strain based. Consequently, the M/χ approach cannot directly accommodate discrete deformations associated with tension stiffening, such as the formation of individual cracks and reinforcement slip. Hence, the M/χ approach can simulate the behaviour prior to cracking purely through mechanics. However, for post‐cracking behaviour it requires empirically derived correction factors, such as empirically derived flexural rigidities, to allow for the deformations associated with tension stiffening. This paper presents a displacement‐based moment–rotation (M/Θ) approach for determining the behaviour of PC beams by applying the Euler‐Bernoulli theorem of plane sections, as opposed to the conventional M/χ approach of a linear strain profile. Being based on plane sections, the M/Θ approach deals directly with displacements and, consequently, can simulate the mechanics of tension stiffening directly. The approach is shown to accommodate the time effects of concrete creep, shrinkage and reinforcement relaxation and can develop equivalent flexural rigidities directly from mechanics.

Behaviour of RC Beams without Cover Concrete

Behaviour of RC Beams without Cover Concrete

Experimental Study on Mechanical Behaviors of Damaged RC Beams after Reinforcement

Based on 6 testing beams in site cast, the mechanical behaviors of RC beams after reinforcement are analyzed. Concrete-replacing and grouting were used to reinforce the damaged component. When the reinforcement materials reached sufficient strength and maturity, beams were subjected to experiments of bending bearing capacity. Cracking load and ultimate bearing capacity were analyzed relatively, drawing some conclusions which could use as the reference of reinforcing concrete structure after damage.

Simulation Analysis on Shear Behavior of RC Beams with Near-Surface Mounted GFRP Bars

This paper focuses on the characterization of shear behavior of RC beams strengthened with Near-Surface Mounted (NSM) GFRP bars. Based on ABAQUS, the finite element model for the shear behavior is established and the simulated results are compared with the test results. The parameters including spacing and inclination of GFRP bars, mechanical properties of the groove-filling epoxy, stirrup ratio and shear-span ratio of the specimen beams for the shear behavior are discussed. The simulated results show that there has a good agreement with the experiment results. The beams strengthened with NSM GFRP bars have a significant improvement in shear capacity. Further more, the analysis results on the parameters indicate that ultimate shear capacity of the beam strengthened with NSM-GFRP bars gradually increases with the decrease of spacing of GFRP bars. The ultimate bearing capacity increases of the strengthened beam with inclination of 45° is the more larger than those of 60° and 90°. The different types of epoxy adhesive and shear-span ratio have a great influence on the load-deflection curves of the strengthened beams.

Research on Mechanical Behavior of RC Beams Strengthened with CFRP by Anti-Arch Method

The mechanical behavior of RC beam strengthened with CFRP by anti-arch method and directly pasting CFRP through model test is analyzed. It explains that the reinforced RC beam with CFRP by anti-arch method can solve the influence of beam's loading by the secondary stress which exists in the method of pasting CFRP directly in strengthening RC beams improve the beam's load when it cracks and the carrying capacity, and decrease the deflection deformation and crack width and gap when the beam carries load. It can make the most use of high strength of tensile properties of CFRP.

An Experimental Study on the Effects of Biaxial Bending due to Eccentric Load on RC Beam

Eccentric loads are very common in structures due to building configuration. Unequal slab length, circular ramp, large cantilevers are very common in modern architecture. The RC beams in previous studies were tested under the three and four point uniform loads. Therefore, a simple testing setup was arranged to understand the behaviour of RC beam under eccentric load applied at mid span. In this study the single point load applied eccentrically on RC beam. The beams were tested at different eccentricity and compared with control beam tested under the uniform load or zero eccentricity. Results have shown a drastically reduced crack load up to 54% compared to control beam as the eccentricity increased. However, small changed in ultimate load carrying capacity was observed up to 60mm eccentricity. Eccentric load caused biaxial bending due to high concentration of load on one side of beam, which change failure mode of RC beam from ductile to brittle.

Study on Dynamic Shear Resistance of RC Beams

The aim of this study was to investigate the dynamic shear failure behavior of RC beams under rapid loading through an experimental study and also to set up a strut-and-tie model with loading rate effect to predict the dynamic shear resistance of RC beams. Thus, rapid loading test with 24 RC beams with a shear span-to-deep ratio of 1.9 was performed, in which shear reinforcement ratio and loading rate were variable. All of the RC beams exhibited shear compression failure. Although the shear resistance increases with increasing loading rate, the influence of loading rate on the shear resistance clearly depends on shear reinforcement ratio. The strut-and-tie model with loading rate effect was finally developed, in which the thickness of the compression strut was formulated to be increased with an increase in loading rate. The developed strut-and-tie model was good agreement with the experimental results.

Interfacial Slip Calculation of RC Beams Strengthened with FRP Plate under Mid-Span Concentrated Loads

The collaborative work between fiber reinforced polymer (FRP) and concrete is achieved through the binder, so the interface of them is the weak links. The interfacial slip between FRP and concrete beam is one of the key factors to affect the behaviors of RC beams strengthened with FRP plate. According to elasticity theory, this study analyzes the theoretical analysis of interfacial slip of RC beams strengthened with FRP plate under mid-span concentrated loads. The analytical model is established, and the differential equation of interfacial slip of RC beams strengthened with FRP plate is established. Using the boundary conditions, the calculated formula of interfacial slip is deduced under mid-span concentrated loads.

지속하중과 환경영향을 받은 MF-FRP 보강보의 구조건전성 평가

Mechanically fastening FRP (MF-FRP) strips using nails and anchors, has been shown to provide a more ductile behavior to the strengthened structural element than using bonded FRP. To further advance the state of the knowledge on this strengthening method, the current study examined environmental effects for six months on MF-FRP beams. Reinforced concrete beams strengthened with mechanically fastened FRP strips and subjected to sustained loads for six months were exposed to outdoor weather and constant high temperatures (). For comparison, the behavior of RC beam with and without sustained loads was evaluated. Results from flexural tests did not show any significant degradation or change of failure mode as a result of sustained load and of environmental effects such as high temperatures and outdoor weather over a period of six months. Failure of the beams was governed by FRP delamination followed by concrete crushing as not much load applied to the nail and anchors because of slip effects.

Interfacial Shear Stresses Calculation of RC Beams Strengthened with FRP Plate under Symmetry Concentrated Loading

The performance of the interface between fiber reinforced polymer (FRP) and concrete is one of the key factors to affect the behaviors of RC beams strengthened with FRP plate. Under external loading, the relative slip occurring on the interface between FRP plate and concrete causes the redistribution of stress and then the bearing capacity of the member is reduced. This study analyzes the effect of the interfacial soft behavior on the interfacial shear stresses of RC beams strengthened with FRP plate under symmetry concentrated loading. The analytical model is established, and the differential equations of interfacial shear stresses of RC beams strengthened with FRP plate are established. The calculated formulas of interfacial shear stresses are deduced under symmetry concentrated loading.