Service life prediction model for marine concrete structures considering structural shape and time-dependent behaviour

A new service life prediction model for marine concrete structures considering the structural shape and timedependent behaviour of model parameters was proposed in this study. First, a lumped concentration matrix for both triangular elements of two-dimensional diffusion and linear elements of one-dimensional diffusion was developed based on the Galerkin's method of weighted residual and approximate interpolation function, respectively. Then, a dual time-dependent numerical model for chloride diffusion in marine concrete structures was established by considering the time-dependent behaviour of both chloride diffusion coefficient (D) and surface chloride concentration (Cs). Meanwhile, a new service life prediction model for marine concrete structures that considers the influences of structural shape and time-dependent behaviour of model parameters was proposed. Finally, the influences of the structural shape and the time-dependency of D and Cs on service life were investigated. Analysis results show that the service life would be underestimated if the time-dependent behaviour of D or Cs were ignored, while the service life would be overestimated when the influence of structural shape was neglected. Compared with Cs, the time-dependent behaviour of D has more significant effects on service life of marine concrete structures.