Fatigue Behavior in the Carbon-Fiber-Reinforced Polymer-to-Concrete Bond by Cyclic Pull-Out Test: Experimental and Analytical Study

Fatigue Life Prediction Model of FRP–Concrete Interface Based on Gene Expression Programming

“…For EB FRP, since there are fewer experimental studies on the fatigue life of FRP-to-concrete width ratio, no consistent conclusion has been drawn. Both this paper and the literature [6,12] studying the effect of FRP-to-concrete width ratio on the fatigue life have concluded that the interfacial fatigue life increases with the increase in the ratio of the width of FRP and concrete. It is worth stating that when studying the relationship between the groove's depth-to-width ratio and the fatigue life, it only makes sense to control the groove depth or width to be constant.…”

“…A total of 219 sets of FRP-concrete interfacial fatigue shear test data were collected from the literature [10][11][12][13][14][16][17][18][19][20][21][22][23][24][25][26][27][28][29], including 108 sets of EB FRP-concrete interfacial fatigue tests and 111 sets of NSM FRP-concrete interfacial fatigue tests, and the direct shear tests of the two types of reinforcement are shown in Figure 2. It is worth noting that since bridge structures are generally subjected to traffic loads with a low load amplitude and generally fail under high weekly fatigue loads, the number of loading times before damage of the specimens selected in this paper are all greater than 1000 [30].…”

“…The existing S-N curve shows the stress level S and fatigue life N expression, which has two main forms: single logarithm and double logarithm. Zhu et al [8] considered the effect of concrete strength in addition to the stress level, Li [7] proposed a model for fatigue life prediction considering multiple factors, and Fathi et al [12] modified Li's model based on the collection of experimental data. To further evaluate the prediction effect of the FRPconcrete interface fatigue life model (GEP model) proposed in this paper, it is compared with several more common prediction models in the literature, the calculation formulas for which are shown in Table 5.…”

“…Min [11] investigated the effect of the fatigue load amplitude (the difference between the upper and lower limits of fatigue load) and the fatigue load level (the mean value of the upper and lower limits of fatigue load) on fatigue life using the single-shear pull-out test, which showed that the fatigue life decreases with the increase in the fatigue load amplitude and the fatigue load level. Fathi et al [12] investigated the effects of composite type, CFRP-to-concrete width ratio, and bond length on the interfacial fatigue adhesion performance using double-shear pull-out tests. The results showed that the fatigue life of fabric sheet CFRP-reinforced concrete was larger than that of laminated CFRP-reinforced concrete and that the interfacial fatigue life increased with the increase in the bond length and the CFRP-to-concrete width ratio.…”