Fatigue Performance Of Concrete Beams Research Articles

Shear fatigue behavior of reinforced concrete beams produced with manufactured sand as alternatives for natural sand

Compared to natural sand, manufactured sand (M-Sand) has significant differences in terms of stone powder content, particle size distribution, and particle shape. The fatigue performance of M-Sand concrete structures is a crucial problem for the application of M-Sand in significant engineering structures. In this study, four different types of fine aggregates were selected to investigate the shear fatigue behavior of reinforced concrete (RC) beams by considering the influence of the maximum load level. Next, the performance indexes of the fatigue life of M-Sand concrete beams were evaluated. The results showed that the fatigue failure processes of concrete beams produced with different sand types were similar. The fatigue life of concrete beams was found to be related to the stress or load range. At the same maximum load level, the methylene blue (MB) value is a critical index that influenced the fatigue life of concrete beams containing M-Sand. Moreover, the fatigue life showed a linear logarithmic relationship with the average permanent deflection of Stage II. The total dissipation energies of the concrete beams in Stage II were different for the various fine aggregates. Generally, the higher the total dissipation energy, the longer the fatigue life of the concrete beam. The average dissipation energy in Stage II can be used as a characteristic index for evaluating the fatigue performance of concrete beams produced with different types of fine aggregates. • Shear fatigue behaviors of sixteen reinforced concrete beams containing manufactured sand were innovative analyzed. • Three different types of manufactured as well as natural sand were used in experimentally program. • The fatigue life of manufactured sand concrete beams was found to be related to the stress or load range. • The magnitude of the dissipation energy together with permanent deflection could indicate the fatigue life of concrete beams.

Fatigue behavior of concrete beams reinforced with glass- and carbon-fiber reinforced polymer (GFRP/CFRP) bars after exposure to elevated temperatures

This paper deals with fatigue performance of concrete beams reinforced with fiber reinforced polymer (FRP) bars after exposure to elevated temperatures. A total of 13 concrete beams reinforced with glass- and carbon-fiber reinforced polymer (GFRP/CFRP) bars were tested under static and fatigue loading after exposure to different levels of elevated temperatures. The influences of elevated temperature, holding time, fatigue load level and FRP bar type on the fatigue behavior of beams were investigated. The results showed that the elevated temperature exposure reduced more severely the fatigue life of GFRP-reinforced concrete beam than that of CFRP-reinforced beam below 400 °C, and GFRP- and CFRP-reinforced beams both lost their bearing capacities when the exposure temperature reached 600 °C. The elevated temperature accelerated the development of concrete strain, crack width and deflection of FRP-reinforced concrete beams with the number of fatigue cycles. The mid-span deflection was predicted using some existing models, and the CEB-FIP model showed the best accuracy with the coefficient of variation of 2.8–7.0%. The fatigue strength of GFRP- or CFRP-reinforced concrete beams is not affected by elevated temperatures up to 400 °C for 2 h.

Analysis of flexural fatigue failure of concrete made with 100% coarse recycled and natural aggregates

In this study, the flexural fatigue performance of concrete beams made with 100% Coarse Recycled Concrete Aggregates (RCA) and 100% Coarse Natural Aggregates (NA) were statistically commanded. For this purpose, the experimental fatigue test results of earlier researcher were investigated using two parameter Weibull distribution. The shape and scale parameters of Weibull distribution function was evaluated using seven numerical methods namely, Graphical method (GM), Least-Squares (LS) regression of Y on X, Least-Squares (LS) regression of * on Y, Empherical Method of Lysen (EML), Mean Standard DeviationMethod (MSDM), Energy Pattern FactorMethod (EPFM) andMethod of Moments (MOM). The average of Weibull parameters was used to incorporate survival probability into stress (S)-fatigue life (N) relationships. Based on the Weibull theory, as single and double logarithm fatigue equations for RCA and NA under different survival probability were provided. The results revealed that, by considering 0.9 level survival probability, the theoretical stress level corresponding to a fatigue failure number equal to one million cycle, decreases by 8.77% (calculated using single-logarithm fatigue equation) and 6.62%(calculated using double logarithm fatigue equation) in RCAwhen compared to NAconcrete.

Experimental study on deflection of partially prestressed concrete beams at different corrosion rates under fatigue load

This paper studies the deflection under fatigue load failure and the corrosion fatigue life of partially prestressed concrete beams through the static test and fatigue test of 6 different corrosion rates of partially prestressed concrete beams. The experimental results show that: 1) The corrosion inserts a great influence on the fatigue failure of concrete beams; the fatigue failure of reinforced concrete beams at a low corrosion rate is mainly caused by fatigue fracture of tensile rebars; and when the corrosion rate is high, the failure mode of concrete beams evolves into the cracking and final crushing of reinforced concrete in compressive zone. 2) As the corrosion rate increases, the fatigue life of concrete beams decreases significantly, which affects the fatigue performance of concrete beams. (3) With the increase of fatigue load, the development of mid-span deflection of the test beams shows an obvious rule of three stages: the deflection grows faster at the initial stage, and slower at the medium stage.

Analysis of flexural fatigue failure of concrete made with 100% Coarse Recycled Concrete Aggregates

The paper presents results of an investigation carried out to analyze the flexural fatigue performance of concrete beams made with 100% Coarse Recycled Concrete Aggregates (RCA) and its comparison with that of concrete made with 100% Coarse Natural Aggregates (NA). The fatigue performance of concrete beams made with RCA as well as NA has been assessed in terms flexural fatigue life distributions and two-million cycle endurance limit. Experiments were conducted to obtain the flexural fatigue lives of concrete beam specimens made with 100% RCA as well as 100% NA under different stress levels and further compared with literature available on NA. Specimens of size 100mm×100mm×500mm were tested under four point flexural fatigue loads applied at a frequency of 10Hz. It has been shown that the fatigue life distributions of concrete mixes made with 100% RCA and 100% NA can be modeled by the two-parameter Weibull distribution. The values of the shape parameters of the Weibull distribution obtained for concrete made with RCA have been found to be smaller than that of concrete made with NA in present investigation and previous studies on NA, thus indicating higher variability in the distribution of flexural fatigue life of concrete made with RCA viz. a viz. concrete made with NA. The two-million cycles endurance limit for concrete made with 100% RCA has been found to be 50%, which is about 8% and 7% lower than that of concrete made with NA in present and previous studies respectively.

Fatigue of Concrete Beams Strengthened with Glass-Fiber Composite under Flexure

A detailed investigation on the fatigue performance of concrete beams strengthened with glass-fiber composite (GFC) is performed in this study. Cyclic load tests were conducted on reinforced concrete beam specimens strengthened with two layers of GFC bonded to the beams’ bottom surface using a special epoxy resin. Midspan-deflection and cracks were measured at different numbers of load cycles and varying fatigue loading levels during the tests. Investigated parameters include total midspan-deflection, residual midspan-deflection after unloading, crack width, crack length, and crack distribution at different loading stages. The fatigue performance of concrete beams strengthened with GFC was evaluated by comparing the deflections, crack sizes, and crack distributions with unstrengthened beams. The concrete beams strengthened with GFC investigated in this study showed significant improvement on fatigue performance.

Cyclic Behavior of RC Beams Strengthened with Carbon Fiber Sheets Bonded by Inorganic Matrix

The objective of this paper is to study the fatigue performance of concrete beams strengthened with carbon fiber sheets bonded by an inorganic matrix. Large size reinforced concrete (RC) beams were strengthened with three layers of carbon fiber sheets and tested under fatigue loading. The relationship between fatigue strength, crack width, and number of cycles was studied and analyzed. Results showed that both load capacity and number of cycles of the RC beams were significantly increased with carbon fiber sheets. The fatigue strength increased by as much as 55% as compared with that of the control beams. Fatigue failure of the RC beams strengthened with carbon fiber sheets bonded with an inorganic matrix started with steel rupturing followed by fiber rupture. It was observed that the fatigue cracks developed during the first few cycles. With increasing number of cycles, the crack width and crack depth increased during the first half million cycles of loading, and thereafter the crack width and depth tended to stabilize.

Closure to “Fatigue Performance of Concrete Beams Strengthened with CFRP Plates” by Richard Andrew Barnes and Geoffrey Charles Mays

Closure to “Fatigue Performance of Concrete Beams Strengthened with CFRP Plates” by Richard Andrew Barnes and Geoffrey Charles Mays

Fatigue Performance of Concrete Beams Strengthened with CFRP Plates

Recent increases in bridge design loading requirements have highlighted the need for fast, efficient, and durable strengthening methods. External steel plate bonding provides a satisfactory solution, but carbon fiber reinforced plastic (CFRP) offers the added advantages of resistance to corrosion, low weight, and high mechanical strength. This paper examines the fatigue performance of CFRP-strengthened concrete beams as part of a project investigating the use of CFRP as an alternative to steel. Five reinforced concrete beams were tested in fatigue; two control beams and three strengthened with externally bonded CFRP plates. Three loading options were used: (1) apply the same loads to both plated and unplated beams, (2) apply loads to give the same stress range in the rebar in both beams, and (3) apply the same percentage of the ultimate load capacity to each beam. Fatigue fracture of the internal reinforcement steel would appear to be the dominant factor governing failure, and it would appear reasonable to expect the same fatigue life for plated and unplated beams with comparable values of stress range in the steel bar.

Fatigue Performance of Concrete Beams Strengthened with CFRP Plates

Recent increases in bridge design loading requirements have highlighted the need for fast, efficient, and durable strengthening methods. External steel plate bonding provides a satisfactory solution, but carbon fiber reinforced plastic (CFRP) offers the added advantages of resistance to corrosion, low weight, and high mechanical strength. This paper examines the fatigue performance of CFRP-strengthened concrete beams as part of a project investigating the use of CFRP as an alternative to steel. Five reinforced concrete beams were tested in fatigue: two control beams and three strengthened with externally bonded CFRP plates. Three loading options were used: (1) apply the same loads to both plated and unplated beams, (2) apply loads to give the same stress range in the rebar in both beams, and (3) apply the same percentage of the ultimate load capacity to each beam. Fatigue fracture of the internal reinforcement steel would appear to be the dominant factor governing failure, and it would appear reasonable to expect the same fatigue life for plated and unplated beams with comparable values of stress range in the steel bar.