Yingang Wang’s research while affiliated with Wuhan University of Technology and other places

The seismic vulnerability of Cable-stayed Bridges (CSBs) in high-earthquake intensity areas can be of significant concern to structural safety and resilience. A promising design practice for CSBs depends on decoupling the girder from the girder-pylon connection and involving energy dissipation devices such as fluid viscous damper (FVD) to mitigate the seismic responses. However, the parametric damper optimization algorithm and experimental validation on the FVD of a longitudinal aseismic system for CSB is still limited. In this study, three longitudinal aseismic systems (a semi-floating system with an elastic or damper connection, and a pylon girder consolidation system with a rigid connection) were investigated and compared based on the actual bridge Xigu Yellow River CSB erected in Lanzhou, China. The non-linear time history methodology was implemented to analyze the pylon and girder's displacement and internal force responses, and the fluid viscous damper (FVD) aseismic system was the optimal choice considering the oval seismic performances. The optimal damping parameters were obtained by conducting parametrical analysis based on qualitative analysis and non-linear multi-function optimization in the pylon-girder and auxiliary pier-girder connections. A full-scale FVD model was designed and manufactured to conduct low velocity, constitutive law, and damping efficiency tests. The experimental results indicate that FVD achieved good energy dissipation capability and stability. FVD damping parameters were deduced according to the constitutive law test. The optimal analytical FVD damping parameter agreed well with the experimental results. Furthermore, the optimization was implemented in the final bridge design, referencing longitudinal aseismic systems for CSBs.

The long-term durability of glass fiber reinforced polymer (GFRP) bars under different conditioning environments is investigated in this paper. A batch of GFRP bars exposed to alkaline accelerated corrosion concrete environment for 8 years is studied. The long-term tensile strength degradation law/micro deterioration mechanism are analyzed, and the tensile strength prediction model of GFRP bars is established. By comparing the estimated results with the long-term experimental data, it is found that the prediction model fits the first stage degradation data of GFRP bars well and has high accuracy. However, the long-term durability of GFRP bars is significantly underestimated based on the prediction results in the second stage, so an improved long-term tensile strength prediction model is proposed. Finally, the 8-year residual tensile strength of GFRP bars is evaluated according to three current codes.