Reliability assessment on stability of tunnel-type anchorages

The tunnel-type anchorage (TTA) is recently being used in large-span suspension bridge, however, the reliability is not yet investigated and the pullout load carrying behavior is also not fully understood. Hence, in this paper, the pullout behavior of TTA during loading was investigated using a finite element program. Subsequently, extensive parametric studies were carried out to assess the factor of safety for TTA. Based on the study results, a predictive model for the safety factor of TTA was developed via an artificial neural network approach, and then the predictive model was implemented into a spreadsheet containing an automated search algorithm to calculate the reliability probability of TTA. The calculation results were evaluated using Monte Carlo simulation. The effects of the design parameters of plug body and its variability on the reliability of the TTA were discussed. Besides, a series of implications for design are also proposed. Some useful conclusions regarding the stress distribution and evolution of TTA during loading as well as the reliability are presented.