**Acknowledgements**

*Natural Hazards - Risk, Exposure, Response, and Resilience*

However, all the results can be found elsewhere [22].

From the test results, it can be concluded that:

**5. Conclusions**

the top ends of the RC column, respectively (**Figures 7**, **8**, and **10**). The comparison included the observed damage, the hysteretic behavior, the maximum moment, and the associated rotation. An overall good agreement was found between the substructured pseudo-dynamic test and the response analysis results. The unloading stiffness of the hysteretic moment-rotation curve of the PC girder that was obtained from the response analyses was different from the unloading stiffness that was found during the sub-structured pseudo-dynamic test. However, the total dissipated energy that was obtained from the response analyses was found to be almost

The moment time history curves that were obtained from the sub-structured pseudo-dynamic test for the left end of the PC girder and the bottom and the top ends of the RC column are shown in **Figure 11a**, **c** and **e**, respectively. The corresponding moment time history curves that were obtained from the response analyses are shown in **Figure 11b**, **d** and **f**, respectively. The comparison between the experimental and analytical moment time histories shows good agreement, thus verifying the accuracy of the used analytical hysteretic restoring force models for both the prestressed and the reinforced concrete members of the viaduct model. Consequently, the restoring force models can be further employed in a parametric study that includes the yielding ratio (Py/mg), the elastic natural period, and the strength ratio between the PC girder and the RC columns. A parametric study that included these parameters is carried out in order to verify the study conclusions as well as to fully understand the response behavior of the viaduct structures during severe earthquake excitations. Because of space limitations, the results of the parametric study are not included in this paper.

The objective of this study was to clarify the inelastic response behavior of partially prestressed concrete girders of viaduct structures during severe earthquake excitations. A study that includes experimental and analytical phases was carried out. Small-scaled models were employed so as to represent actual viaduct structures. Specimens representing the PC girders of the viaducts were tested experimentally. Two testing techniques were employed in the experimental phase of the study. The first technique was a statically reversed cyclic loading test. The objective of the statically reversed cyclic loading test was to study the inelastic response behavior of the PC girders and to obtain the hysteretic-load deformational characteristics. The sub-structured pseudo-dynamic testing technique was implemented as the second testing technique. During the sub-structured pseudo-dynamic test, the PC girder was tested experimentally, and the RC columns of the viaduct structure were simulated analytically. Response analyses for the same viaduct model in terms of hysteretic moment-rotation curves and time histories were carried out.

1.Not only the RC columns but also the PC girders are subjected to inelastic deformations that may cause a considerable damage during earthquake excitations. As a consequence, adequate care should be given to the PC girder design to satisfy the strength and ductility requirements of a seismic-resistant structure.

2.A comparison between the experimental and analytical results in terms of the resulting skeleton curves, time histories, hysteretic curves, and the dissipated energy was made. A good agreement between the experimental and analytical results was found. Therefore, the analytical model can be utilized

similar to the experimentally dissipated energy during the excitation.

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The author would also like to acknowledge the members of the structural laboratory at Saitama University who provided assistance during the experimental phase of the study. The author would like to acknowledge Dr. Hiroshi Mutsuyoshi, a structural engineering professor at Saitama University, for his valued assistance, full support, and appreciated comments.
