scholarly journals Long-term Deflections of Hybrid GFRP/Steel Reinforced Concrete Beams under Sustained Loads

2020 ◽  
Vol 6 ◽  
pp. 1-11
Author(s):  
Phan Duy Nguyen ◽  
Vu Hiep Dang ◽  
Ngoc Anh Vu ◽  
Polikutin Aleksei Eduardovich
Keyword(s):  
Reinforced Concrete ◽  
Steel Reinforcement ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Rc Beams ◽  
Climate Conditions ◽  
Glass Fiber Reinforced ◽  
Sustained Loads

One of the solutions to improve the flexural behavior of Glass fiber reinforced polymer (GFRP) reinforced concrete (RC) beams is the addition of tensile longitudinal steel reinforcement. The numerous studies to date on hybrid GFRP/steel RC elements have mainly focused on the static and short-term responses, very little work has been done regarding the long-term performance. This paper presents experimental results of time-dependent deflections of cracked GFRP and hybrid GFRP/steel RC beams during a 330-day-period in natural climate conditions. Three hybrid GFRP/steel and one GFRP RC beams with dimensions 100×200×2000 mm were tested in four-point bending. Different steel reinforcement ratios were used to evaluate the effect of the steel reinforcement on the long-term behavior of the beams. Experimental results show that the immediate deflections are inversely proportional to the additional steel reinforcement. With the same initial instantaneous deflection, the total deflection increases when increasing the steel reinforcement ratio. Also, temperature (T) and relative humidity (RH) significantly affect the long-term deflection of the tested beams. The measured long-term deflections were found to be in good agreement with the theoretical values calculated from the proposed method. However, there was an overestimation when using ACI 440.1R-15 or CSA-S806-12 procedures.

Experimental Study on Residual Flexural Behavior of Reinforced Concrete Beams after Exposure to Fire

2012 ◽  
Vol 457-458 ◽  
pp. 183-187 ◽  
Author(s):  
Yu Ye Xu ◽  
Bo Wu ◽  
Ming Jiang ◽  
Xin Huang
Keyword(s):  
Reinforced Concrete ◽  
Experimental Studies ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Building Structures ◽  
Rc Beams ◽  
Flexural Capacity ◽  
Shaped Beam ◽  
Rectangular Beam

Reinforced Concrete (RC) beams in the building structures are usually assumed as a ‘T’-shaped beam when the effects of adjacent slab flange are considered. However, experimental studies on residual flexural behavior of ‘T’-shaped RC beams are rarely reported. The residual flexural behavior of two RC rectangular beams and one RC ‘T’-shaped beam after exposure to ISO834 standard fire were experimentally investigated in the paper. The detailed experimental results, including the measured temperatures, flexural capacity, load-deflection curves and concrete strain are presented. The effects of flange on temperature distribution and residual flexural behavior of RC beams were analyzed. The experimental results show that: (a) the assumption of plane section is applicable for RC ‘T’-shaped beam. (b) The flexural capacity of RC rectangular beam was decreased 18.5% after exposure to fire for 2 hours, but the ultimate mid-span deflection was increased 55.1%. (c) The residual flexural capacity and the ultimate mid-span deflection of RC rectangular beam after fire was respectively increased 8.4% and 9.9% due to the effect of flange.

scholarly journals Effect of loading rate on flexural behavior of concrete and reinforced concrete beams

2021 ◽  
Vol 15 (3) ◽  
pp. 136-143
Author(s):  
Nguyen Trung Hieu ◽  
Nguyen Van Tuan
Keyword(s):  
Reinforced Concrete ◽  
Loading Rate ◽  
Plain Concrete ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Displacement Curve ◽  
Rc Beams ◽  
Three Point Bending ◽  
Loading Rates ◽  
Hydraulic Servo

The elasto-plastic characteristics of plain concrete are inevitably affected by the loading rate. This paper presents an experimental investigation on the effect of loading rate on flexural behavior of concrete and reinforced concrete (RC) beams, which was carried out with Walter+bai electro-hydraulic servo system. Three-point bending tests on 100 × 100 × 400 mm prismatic concrete samples and 80 × 120 × 1100 mm RC beams with different displacement controlled loading rates of 0.01 mm/min, 0.1 mm/min, and 3 mm/min were imposed. Based on the test results, the effects of loading rates on the load-displacement curve, cracking, and ultimate load-carrying capacities of RC beams were evaluated.

Moment Capacity of FRP Reinforced Concrete Beam Assessment Based on Centerline Geometry

2013 ◽  
Vol 486 ◽  
pp. 211-216
Author(s):  
Jan Zatloukal ◽  
Petr Konvalinka
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Steel Reinforcement ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Moment Capacity ◽  
Frp Composite ◽  
Load Carrying ◽  
The One

The flexural behavior of FRP (Fiber Reinforced Polymer) reinforced concrete beam has been the topic of intensive previous research, because of the spread of use of modern FRP composite materials in the building industry as concrete reinforcement. The behavior of FRP reinforced member is different from the one reinforced with regular steel reinforcement, mainly because of vast difference between moduli of elasticity of FRP composite reinforcement bars and steel. This difference results in the fact that conventional design methods used for years in the field of reinforced concrete structures using steel reinforcement give poor results if attempted use with FRP reinforced structural members. Results of conventional methods are so poor that use of such methods would be dangerous they tend to overestimate load carrying capacity and underestimate deformations both resulting in unsafe predictions. This paper points to formulating easy to use and comprehensible method of predicting moment capacity of FRP reinforced concrete beams subjected to bending loading and validation of the proposed method via set of experiments.

Implication of Unbondedness in Reinforced Concrete Beams

2012 ◽  
Vol 587 ◽  
pp. 36-41 ◽  
Author(s):  
S.F.A. Rafeeqi ◽  
S.U. Khan ◽  
N.S. Zafar ◽  
T. Ayub
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Failure Mode ◽  
Shear Failure ◽  
Concrete Beams ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Flexural Capacity ◽  
Flexural Reinforcement

In this paper, behaviour of nine (09) RC beams (including two control beams) after unbonding and exposing flexural reinforcement has been studied which were intentionally designed and detailed to observe flexural and shear failure. Beams have been divided into three groups based on failure mode and unbounded and exposed reinforcement. Beams have been tested under two-point loading up to failure. Experimental results are compared in terms of beam behaviour with respect to flexural capacity and failure mode which revealed that the exposed reinforcement does not altered flexural capacity significantly and unbondedness positively influences shear strength; however, serviceability performance of beams with unbonded and exposed reinforcement is less.

Long-term data of reinforced concrete beams subjected to high sustained loads and simplified prediction method

2017 ◽  
Vol 18 (6) ◽  
pp. 850-861 ◽  
Author(s):  
Nicky Reybrouck ◽  
Pieterjan Criel ◽  
Tim Van Mullem ◽  
Robby Caspeele
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Prediction Method ◽  
Reinforced Concrete Beams ◽  
Sustained Loads ◽  
Term Data

scholarly journals Limiting Reinforcement Ratios for Hybrid GFRP/Steel Reinforced Concrete Beams

2021 ◽  
Vol 11 (1) ◽  
pp. 01-11
Author(s):  
Duy Phan Nguyen ◽  
Viet Quoc Dang
Keyword(s):  
Experimental Data ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Steel Reinforcement ◽  
Reinforcement Ratio ◽  
Reinforced Concrete Beams ◽  
Equilibrium Equations ◽  
Steel Reinforced Concrete ◽  
Glass Fiber Reinforced ◽  
Load Carrying

In this work, a theoretical approach is proposed for estimating the minimum and maximum reinforcement ratios for hybrid glass fiber reinforced polymer (GFRP)/steel-reinforced concrete beams to prevent sudden and brittle failure as well as the compression failure of concrete before the tension failure of reinforcements. Equilibrium equations were used to develop a method for determining the minimum hybrid GFRP/steel reinforcement ratio. A method for determining the maximum hybrid GFRP/steel reinforcement ratio was also developed based on the equilibrium of forces of the balanced failure mode. For estimating the load-carrying capacity of concrete beams reinforced with hybrid GFRP/steel, less than the minimum and more than the maximum reinforcement ratio is recommended. Comparisons between the proposed expressions, experimental data, and available test results in the literature shows good agreement between the theoretical and experimental data, with a maximum discrepancy of 7%.

scholarly journals DIAGONAL TENSION FAILURE OF RC BEAMS WITHOUT STIRRUPS / SKERSINE ARMATŪRA NEARMUOTŲ GELŽBETONINIŲ SIJŲ TEMPIAMASIS SUIRIMAS ĮSTRIŽAJAME PJŪVYJE

2012 ◽  
Vol 18 (2) ◽  
pp. 217-226 ◽  
Author(s):  
Guray Arslan
Keyword(s):  
Reinforced Concrete ◽  
Shear Failure ◽  
Concrete Beams ◽  
High Strength ◽  
Theory Of Elasticity ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Codes Of Practice ◽  
Slender Beams

The shear failure of reinforced concrete beams is one of the fundamental problems in civil engineering; however, the diagonal tension strength of reinforced concrete (RC) beams without stirrups is still in question. This paper focuses on the prediction of diagonal cracking strength of RC slender beams without stirrups. In slender beams, flexural cracks develop in the tension zone prior to a diagonal cracking. Using the basic principles of mechanics, but cracking included, and theory of elasticity, a diagonal cracking strength equation is proposed for both normal and high strength concrete beams. The proposed equation, the requirements of six codes of practice and seven equations proposed by different researchers are compared to the experimental results of 282 beams available in the literature. It is found that the predictions from the proposed equation are in good agreement with the experimental results. Santrauka Gelžbetoninių sijų suirimas įstrižajame pjūvyje – viena pagrindinių problemų statybos inžinerijoje. Tačiau skersine armatūra nearmuotų gelžbetoninių sijų įstrižasis tempiamasis stipris nėra visiškai ištirtas. Šiame straipsnyje nagrinėjamas siaurų, be skersinės armatūros gelžbetoninių sijų įstrižojo pjūvio pleišėjimas. Siaurose sijose plyšiai tempiamojoje zonoje atsiranda anksčiau negu įstrižajame pjūvyje. Taikant klasikinius mechanikos principus ir tamprumo teoriją, pasiūlyta normalaus stiprio arba stipriojo betono sijų istrižojo pjūvio atsparumo pleišėjimui apskaičiavimo lygtis. Siūloma lygtis, pagrįsta šešių projektavimo normų reikalavimais ir septyniomis kitų autorių lygtimis bei palyginta su literatūroje pateiktais 282 sijų eksperimentinių tyrimų rezultatais. Nustatyta, kad pagal siūlomą lygtį atlikti skaičiavimai gerai sutampa su eksperimentiniais rezultatais.

Mechanical performance of CFRP enclosed reinforced concrete beams by different shear reinforcement

2020 ◽  
pp. 136943322097478
Author(s):  
Qi Cao ◽  
Jiadong Bao ◽  
Changjun Zhou ◽  
Xianrui Lv
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Mechanical Performance ◽  
Concrete Beams ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Shear Reinforcement ◽  
Four Point Bending ◽  
Expansive Agent

This paper aims to study the flexural behavior of CFRP enclosed reinforced concrete beams with different shear reinforcement. Four-point bending tests were carried out on six concrete beams with different contents of steel fibers (0.5%, 1.0%, and 1.5%) as well as six beams with different stirrup spacing (100 mm, 150 mm, and 300 mm) without fiber. The effect of steel fiber (SF) content as well as stirrup spacing on flexural properties of concrete beams were investigated. Meanwhile, the effect of expansive agent on the properties of specimens was also studied. The data collected in this test include cracking load, ultimate load, mid-span deflection, strain of CFRP (Carbon fiber reinforced polymer), strain of longitudinal steel reinforcement as well as the failure modes. Test results show that both cracking loads and ultimate loads of the SF reinforced beam specimens are generally higher than those of the corresponding stirrup reinforced beam specimens. Experimental results also indicate that the addition of SF can improve the ductility and cracking resistance of specimens. This therefore demonstrates that it is feasible to replace stirrup reinforcement with SF as shear reinforcement. In addition, it exhibits a good agreement between experimental results and analytical predictions in cracking loads and ultimate loads.

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