## 4 Experimental Results
### Failure Mode  
The concrete strains (\(\varepsilon\)) along the \(d_{\text{E(P)}}\) of both sides of the pile for the IAP and GIAP specimens under various \(d\) values were compared in Figure 9. The tensile and compressive \(\varepsilon\) are indicated as the positive and negative \(\varepsilon\), respectively. The \(\varepsilon\) values of the back and front sides of the pile (\(\varepsilon_{\text{(P)}}\) and \(\varepsilon_{\text{(P)}}\)) under various \(d\) values are defined as \(\varepsilon_{\text{(P)}}\)/\(\varepsilon_{\text{(P)}}\)/\(\varepsilon_{\text{(P)}}\), respectively. For instance, \(\varepsilon_{\text{(P)-2 mm}}\) represents the \(\varepsilon\) on the back side of the pile at a \(d\) of \(-2\) mm. Under a negative \(d\), the \(\varepsilon_{\text{(P)}}\) and \(\varepsilon_{\text{(P)}}\) for the IAP and GIAP specimens initially increased and then gradually decreased along the \(d_{\text{E(P)}}\), as shown in Figure 9a,b. The increment in \(\varepsilon_{\text{(P)}}\) for the GIAP specimen was significantly smaller than that for the IAP specimen. When \(d\) was \(-6\) mm, the maximum tensile \(\varepsilon\) for the GIAP specimen (\(83.42\)\(\mu\varepsilon\)) was \(61.3\%\) smaller than that for the IAP specimen (\(215.71\)\(\mu\varepsilon\)). It should be pointed out that the maximum tensile \(\varepsilon\) for the IAP specimen exceeded \(200\)\(\mu\varepsilon\)[50], which means cracks could be found at a \(d_{\text{E(P)}}\) of \(-0.35\) m. When \(d\) was \(-8\) mm, the maximum tensile \(\varepsilon\) on the back side of the GIAP specimen (\(203.1\)\(\mu\varepsilon\)) exceeded \(200\)\(\mu\varepsilon\), which means cracks could be found at a \(d_{\text{E(P)}}\) of \(-0.15\) m. The location of the maximum tensile \(\varepsilon\) of the pile for the GIAP specimen at a \(d_{\text{E(P)}}\) of \(-0.15\) m was shallower than that for the IAP specimen at a \(d_{\text{E(P)}}\) of \(-0.35\) m.  
Under a positive \(d\), the \(\varepsilon_{\text{(P)}}\) and \(\varepsilon_{\text{(P)}}\) for the GIAP specimen initially increased and then gradually decreased along the \(d_{\text{E(P)}}\), while those for the IAP specimen decreased along the \(d_{\text{E(P)}}\), as shown in Figure 9c,d. The increment in \(\varepsilon_{\text{(P)}}\) for the GIAP specimen was significantly smaller than that for the IAP specimen. When \(d\) was \(+2\) mm, the maximum tensile \(\varepsilon\) for the GIAP specimen (\(17.58\)\(\mu\varepsilon\)) was \(92.9\%\) smaller than that for the IAP specimen (\(248.86\)\(\mu\varepsilon\)). It should be pointed out that the maximum tensile \(\varepsilon\) for the IAP specimen exceeded \(200\)\(\mu\varepsilon\), which means cracks could be found at a \(d_{\text{E(P)}}\) = 0 m. When \(d\) was \(+10\) mm, the maximum tensile \(\varepsilon\) on the front side of the GIAP specimen (\(208.38\)\(\mu\varepsilon\)) exceeded \(200\)\(\mu\varepsilon\), which means cracks could be found at a \(d_{\text{E(P)}}\) of \(-0.15\) m. The location of the maximum tensile \(\varepsilon\) of the pile for the GIAP specimen at a \(d_{\text{E(P)}}\) of \(-0.15\) m was deeper than that for the IAP specimen at a \(d_{\text{E(P)}}\) of \(0\) m.  
Figure 8: Concrete strain gauges. It can be concluded that without considering the girder, the \(d\) corresponding to the pile cracks in the GIAP specimen is underestimated, and the locations of the maximum tensile \(\varepsilon\) of the pile are different. The \(\varepsilon\) of the abutment was not provided for the IAP specimen [36]. The \(\varepsilon\) values along the \(d_{\mathrm{E(A)}}\) on both sides of the abutment for the GIAP specimen under \(d\) values of 10, 30, and 50 mm were analyzed, as shown in Figure 10. The \(\varepsilon\) values for the back and front sides of the abutment (\(\varepsilon_{\mathrm{(AB)}}\) and \(\varepsilon_{\mathrm{(AF)}}\)) under different \(d\) values are defined as \(\varepsilon_{\mathrm{(AB)}d}\) and \(\varepsilon_{\mathrm{(AF)}d}\), respectively.