Experiment On Viaduct Pier Of Cross-sea Bridge Under Wind-wave Action And The Wave Force Investigation

With the rapid development of civil infrastructures construction in our country, the large traffic requirement brings forward higher transportation capacity of the coastal region. For the coastal bridge, it always has the length of several kilometers. Among them, the main components is the viaduct bridges with simple-support or continuous structural form except the long-span cable-stayed or suspension navigation bridges. In the marine environments, the coastal bridge would sustain more severe environmental loads, especial the wind and wave actions. If the structures are failure under the wind and wave loads, it will induce huge loss. With the large construction of the coastal bridge, the dynamic responses of the structure under the wind and wave actions have attracted more and more attentions of the researchers. However, this topic has seldom investigated.In this study, an experimental study has been conducted for the viaduct bridge pier of the in-planning constructed Qiongzhou strait transportation channel in the wind tunnel and wave flume facility. Based on the elastic model of the structure, the dynamic responses of the structure under wind-only, wave-only, and wind-wave actions have been investigated. With the test results, the theoretical method to estimate the wave force is also investigated and validated by using the test data. The main contents and the achievement of this study is summarized as follows:(1). Aiming at the viaduct piers investigated in this study, the model design, flow flied calibration, measurement system installation, and test case design have been conducted. Based on the Froude similarity criterion, an elastic model of the structure is designed with the geometric scaling of 1:60 through considering the geometric, kinematic and dynamic similarity. Due to the limitation of the test facility, the wind tunnel and wave flume is reformed. The test system is also installed on the structure and the test case is considered.(2). The experiment was conducted for the elastic model under the wind-only, wave-only, and wind-wave actions. According the sea state and the similarity criterion, the tests were performed for the structure under the wind-only, wave-only and wind-wave actions based on the test data, the dynamic responses of the structural model, including the displacement and acceleration response, the base shear force and bending moment, are analyzed. The analyzed results indicated that the wave is the dominant load of the structure, while the wind load is important for the tip displacement of the bridge pier.(3).The theoretical method to estimate the wave force acting on the viaduct pier is investigated. Based on the diffraction theory of large-scale structure under wave action, the theoretical method to estimate the wave force was established, and the dynamic responses of the structure is analyzed under the wave action. The simulation results by using the diffraction theory is compared with the test data to validate the dynamic response.