Strain-Based Fatigue Analysis of RC Beams Strengthened with FRP Laminates

2012 ◽  
Vol 166-169 ◽  
pp. 1740-1745
Author(s):  
Li Hua Huang ◽  
Yu Jing Li ◽  
Tian Qing Li ◽  
Qing Xiang Wang

The method of strain-based fatigue analysis is applied on the study of fatigue behavior of reinforced concrete (RC) beams strengthened with fiber reinforced polymer (FRP) laminates in this paper. Based on the investigation of fatigue performance of RC beams strengthened with FRP laminates presented in the published literatures, the values of stress concentration factors and the coefficients in Neuber’s rule are suggested. The exponent of fatigue strength in Manson-Coffin formula is discussed so as to having a general stain-life curve which is suitable for the fatigue behavior prediction of RC beam strengthened with FRP laminates. The S-N curves of different stress ratios can be developed and the fatigue lives of the strengthened beams are pointed out.

2011 ◽  
Vol 243-249 ◽  
pp. 5589-5594
Author(s):  
Li Song ◽  
Zhi Wu Yu

The paper presents the results of an experimental study on fatigue performance of corroded reinforced concrete (RC) beams repaired with carbon fiber reinforced polymer (CFRP) sheets. Five beams were constructed. One specimen was strengthened and not corroded; another four specimens were corroded and was strengthened with CFRP sheets. Five specimens were tested in fatigue. The results showed that steel bars corrosion reduced the fatigue life significantly while the CFRP strengthening enhanced the fatigue performance significantly. The effects of reinforcement corrosion on fatigue behavior of the strengthening beam can be attributed to a combination of four factors, including deteriorated bond behavior between reinforcement bras and surrounding concrete, loss of effective cross-section area of reinforcement, the stress concentration on steel bars, and degradation of mechanical properties of steel bars.


2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Ning Zhuang ◽  
Honghan Dong ◽  
Da Chen ◽  
Yeming Ma

This paper presents results from experiments on aged and seriously damaged reinforced concrete (RC) beams strengthened with different arrangements of external carbon fiber-reinforced polymer (CFRP) laminates and end anchorages. Seven RC beams from an old bridge, measuring 250 × 200 × 2300 mm, were tested. All specimens were loaded to yield load to evaluate initial mechanical properties. Then, these seriously damaged specimens were repaired using different CFRP-reinforcing schemes and reloaded to failure. The yield load growth due to CFRP reinforcement ranged from 5% to 36%. Different parameters including CFRP dimension and position, bonding length, and end anchorage were investigated and facilitated conclusions on beam ductility, load-midspan deflection response, and failure mode. This research contributes to knowledge about the CFRP repair of aged and seriously damaged beams to ensure better performance in overloaded conditions.


2015 ◽  
Vol 2 (1) ◽  
Author(s):  
N. Aravind ◽  
Amiya K. Samanta ◽  
Dilip Kr. Singha Roy ◽  
Joseph V. Thanikal

AbstractStrengthening the structural members of old buildings using advanced materials is a contemporary research in the field of repairs and rehabilitation. Many researchers used plain Glass Fiber Reinforced Polymer (GFRP) sheets for strengthening Reinforced Concrete (RC) beams. In this research work, rectangular corrugated GFRP laminates were used for strengthening RC beams to achieve higher flexural strength and load carrying capacity. Type and dimensions of corrugated profile were selected based on preliminary study using ANSYS software. A total of twenty one beams were tested to study the load carrying capacity of control specimens and beams strengthened with plain sheets and corrugated laminates using epoxy resin. This paper presents the experimental and theoretical study on flexural strengthening of Reinforced Concrete (RC) beams using corrugated GFRP laminates and the results are compared. Mathematical models were developed based on the experimental data and then the models were validated.


2011 ◽  
Vol 243-249 ◽  
pp. 621-624
Author(s):  
Gui Bing Li ◽  
Yu Gang Guo

Bonding fiber reinforced polymer (FRP) laminates to the tension face of RC members has been proven to be an effective method to improve the flexural strength. However, structural members are not only needed to have adequate strength, but also to have adequate performance of deformation at service load levels. To evaluate the deflection of externally FRP-strengthened RC beams, a total of 18 RC beams, including 16 beams strengthened with CFRP laminate under different preload levels and 2 control beams, were tested. Based on the assumption that the section of the beam behaves a tri-linear moment-curvature response characterized by pre-crack stage, post-crack stage and failure stage and the test results, this paper presents a modified model to evaluate the deflection of CFRP-strengthened RC beams. The present modified model was verified by the similar test results, and shows a good agreement with the test results.


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