During the 1995 Kobe earthquake, damages were observed in the Daikai subway station and adjacent tunnels. It was the first large-scale underground structure that failed under the earthquake excitation. Numerical and experimental analyses have been conducted to study the failure process of the Daikai station. However, the issue of the scale ratio still exists in the shaking table tests of underground structures. In order to tackle this issue, a hybrid simulation technique is developed here to study the seismic performance of a typical subway station. Based on the previous research, it is found that the central column is the critical component of the structure. Therefore, a reinforced concrete central column is physically tested in the hybrid simulation process. On the other hand, the remaining parts of the structure and soil domain are numerically modeled at the same time. Four hybrid simulation cases are conducted with peak ground accelerations of 0.01 g, 0.1 g, 0.22 g, and 0.58 g. The test results of displacement and shear force are compared with the analytical results. Moreover, the good agreement between the test results and numerical results validate the accuracy of the proposed hybrid test method. After the hybrid simulation process, a quasi-static test is conducted to illustrate the mechanical properties of the central column after the earthquake excitation.

This paper recounts a real-time hybrid simulation (RTHS) that employed a shake table coupled with an actuator to evaluate the seismic performance of a single-span girder bridge. The test specimen for this RTHS was a scaled single-span girder bridge, which was subjected to Loma Prieta excitation in the test. In the RTHS, the bridge specimen, which lacked mass on top of the bridge deck, was physically tested by a shake table and an actuator, whilst the mass on the bridge, as well as the pile foundation and the soil were modeled numerically. OpenSEES was used for numerical modeling and OpenFresco was used for the communication between the test system and numerical model. An adaptive time series (ATS) technique was employed to compensate for time delay in the RTHS. In this way, a novel bridge engineering RTHS application case composed of shake table and actuator control was presented. To validate the results of the RTHS, a shake table test (STT) of the bridge structure with full mass on the bridge deck was conducted correspondingly. Comparing the RTHS and STT results, it can be concluded that acceleration histories, bearing deformation histories, and strain histories of the selected points matched well. The application of RTHS to assess the seismic behavior of the single-span girder bridge was reasonably verified in this paper.

Soil station system seismic issues have been highly valued in recent years. In order to investigate the dynamic seismic behaviors of the intermediate column in soil station systems, a hybrid test of a soil station system was conducted. The soil station model was performed with OpenSees. Virtual hybrid simulation was fulfilled with adapter elements. A hybrid model, composed of the steel column specimen and the remainder numerical model, was assembled using the OpenFresco framework. An intermediate column was treated as the physical substructure, while the rest of the soil station system was treated as the numerical substructure in a hybrid simulation. The hybrid test results are compared with the analytical results. The data obtained from such tests show that the system can accurately reflect the mechanical properties of intermediate columns in soil station systems. A hybrid simulation would be a proper way to assess the seismic performance of a soil station system.

In the absence of intensive tests on the cable-stayed bridges under non-uniform excitation, this study provides a practical and accurate approach to investigate the seismic response of cable-stayed bridges considering spatially varying earthquake inputs. The cable-stayed bridge model with a scale ratio of 1:120 was designed and tested on a newly-developed dual shake table system. Firstly, the modal test was conducted to evaluate the accuracy of the designed specimen. Secondly, both the same input cases and the different inputs cases were executed to study the wave passage effects on bridge specimen’s dynamic response. Lastly, the effects of non-uniform excitation and site classification on the experimental bridge’s seismic performance were studied with test results of various soil condition cases. The test results showed that the bending of the girder was magnified, while the swing of the tower was subdued when the effect of wave propagation was considered. Moreover, compared with the same input cases, the different inputs cases reported a larger response to the extent of 80%. Regarding the effects of site conditions, it was concluded that the site of soft soil had more influence on the dynamic responses of such bridge structures than that of the firm soil site.