Analysis of concrete strain of glass fiber cloth under compression:

① Analysis of concrete strain in compression zone of glass fiber cloth specimen B3 The change curve of maximum strain of concrete in compression zone of specimen B3 with fatigue times is shown in Figure 1136. It can be seen from the figure that the maximum strain of the concrete in the compression zone fluctuates greatly within the range of 50000 cycles. Later, with the increase of cycles, the maximum strain of the concrete in the compression zone basically remains unchanged, and the maximum strain of the concrete in the compression zone is 645.5X10-6 ε。 In the test, it was observed that with the increase of the number of cycles, the cracks on the side of the plate gradually extended to the top of the plate, at this time, the height of the neutral axis moved upward.

② Analysis of concrete strain in compression zone of glass fiber cloth specimen B4 The curve of maximum strain of concrete in compression zone of specimen B4 varying with fatigue times is shown in Figure 11-37. Compared with specimen B1, the strain of concrete in compression zone increases at a higher stress level. The strain of compression zone of specimen B4 reaches 1268X10-6 under zero static load ε， Due to the residual strain of the specimen, the strain decreases between 0~10000 times, and the strain change trend of concrete in the compression zone is similar to that of specimen B3, after which the strain increases slowly.