## 5 Conclusions  
In this study, the seismic response of a PSC I-girder bridge under seismic loads, considering the soil properties and the wave passage effect, was investigated. The seismic  
Figure 14: Comparison of response spectrum and maximum bending moment considering the wave passage effect: (**a**) response spectrum of the PSC girder bridge; (**b**) maximum bending moment; (**c**) deformation shape. response of a PSC I-girder bridge was analyzed using the El Centro record, an artificial seismic load generated by SIMQKE, a seismic load modified to meet the U.S. NRC standard, and a seismic load considering the soil properties of the area where the bridge was constructed using the DEEPSOIL program. The peak acceleration of the four seismic loads was 0.357 g, 0.300 g, 0.300 g, and 0.406 g, respectively, while the maximum response acceleration of the bridge was 0.609 g, 0.549 g, 0.782 g, and 0.836 g, respectively. In addition, the maximum bending moment in the bridge was calculated to be 2308.36 kN\(\cdot\)m and 3223.90 kN\(\cdot\)m, respectively, under two seismic loads with the same peak acceleration of 0.300 g, which was confirmed to have a difference of -139%. The response acceleration calculated for the bridge when the real seismic load (El Centro) and the seismic load modified to meet the U.S. NRC standard were applied was compared. The real seismic load (El centro) had a \(\sim\)119% larger maximum response acceleration than the seismic load modified to meet the U.S NRC standard, but the maximum bending moment of the real seismic load (El Centro) was \(\sim\)120% greater than that of the seismic load modified to meet the U.S NRC. The behavior of the PSC girder bridge was analyzed by considering the shear wave velocity for seismic loads and considering the soil properties. After the wave passage effect of 0.06 s, the maximum bending moment dramatically increased, and at the wave passage effect of 0.08 s, a roughly 150% maximum bending moment appeared. When the wave passage effect was 0.05 s, the response spectrum calculated from the response acceleration from the bridge decreased in the 1 st, 2 nd, and 3 rd modes of the bridge, and the response spectrum at the 2 nd mode of the wave passage effect at 0.08 s had \(\sim\)58% of the response spectrum compared to the 2 nd mode of 0.00 s.  
Therefore, in order to ensure the safety of the bridge, considering the uncertainty of the seismic load, it is necessary to take into account the soil properties of the area in which the bridge is constructed, while complying with the seismic load design code. In addition, the wave passage effect calculated using the shear wave velocity of the bedrock in the area where the bridge is constructed should be considered in order to ensure the earthquake resistance of the bridge. However, for the seismic loads applied in this study, it was assumed that the soil properties of the area where the bridge is installed were the same at all points, because the DEEPSOIL and ProShake programs, which are currently in use, apply a one-dimensional equivalent linear seismic site response analysis. The site response analysis program can consider the soil properties in the area where the bridge is constructed according to depth, but it cannot consider the soil properties converted to the horizontal direction. Therefore, in order to confirm the dynamic behavior of the bridge as being similar to that of the real one, it is considered that additional research on the response analysis of the two-dimensional equivalent linear site should be conducted. In addition, the transmission speed of seismic load transmitted to the bridge varies depending on the wave passage effect transmitted from bedrock, the depth of ground, and the characteristics of each stratum. It is therefore necessary to further study the transmission speed of seismic load, depending on the depth of the ground and the characteristics of the stratum. Conceptualization, Y.-M.Y. and G.P. ; data curation, Y.-M.Y. and K.-N.H.; investigation, Y.-M.Y. and S.L. ; supervision, G.P.