Modern Strategies for the Numerical Modeling of the Cyclic and Transient Behavior of Soils

Civil Engineering and Geoscience

A Gradient-Enhanced Damage Approach to Fracture

A gradient-enhanced damage is formulated in which the Laplacian of the internal variable which memorises the damage enters the damage loading function in addition to the conventional dependence on this internal variable itself. The computational setting for this higher-order continuum model is fully elaborated. Its embedment in thermodynamics is discussed and some remarks are made on the additional boundary conditions that arise. Finally, the special case is discussed for which there is a linear relation between the damage variable and the internal variable that memorises the damage evolution

A comparison between the Perzyna viscoplastic model and the consistency viscoplastic model

The elastic-viscoplastic characteristics of the Perzyna model and the Consistency model are considered. Both theories are compared by assessing the evolution of the viscoplastic multiplier, the evolution of the internal variables and the loading/unloading conditions. An explicit expression is derived for the consistency parameter in the Consistency model. Accordingly, it is shown that the Consistency model and the Perzyna model can be treated in a novel, unified algorithmic fashion. Illustrative numerical examples are given to reveal the differences and the similarities between the models, and to elucidate the features of the proposed implicit numerical scheme

A gradient-enhanced damage approach to fracture

A gradient-enhanced damage is formulated in which the Laplacian of the internal variable which memorises the damage enters the damage loading function in addition to the conventional dependence on this internal variable itself. The computational setting for this higher-order continuum model is fully elaborated. Its embedment in thermodynamics is discussed and some remarks are made on the additional boundary conditions that arise. Finally, the special case is discussed for which there is a linear relation between the damage variable and the internal variable that memorises the damage evolution

Relationship between the construction costs and the reliability index of quay walls

Structures, such as quay walls, have to meet a particular level of safety. Consequently, in the Eurocode standards, three reliability classes are distinguished, each corresponding to a target reliability index and set of partial factors. In this study, more insight is acquired into the relationship between the quay wall's construction costs and the associated reliability index β. It appeared that the marginal costs of safety investments of quay walls are fairly low and in the same order of magnitude of the uncertainty of the estimate of the construction costs. Hence, it seems that the current reliability classes, as defined in the Eurocode standards, are non-efficient for quay walls. In addition, this study investigates the influence of the partial factors and three failure mechanisms on the construction costs and the reliability index. It was concluded that for the considered cases, the soil's angle of internal friction strongly influences the construction costs and the β of the quay wall. Furthermore, it follows that economic optimisation in the probabilistic design of quay walls is possible by increasing the target reliability index of the failure mechanism 'insufficient passive soil resistance' and decrease the target reliability index of 'yielding of sheet pile profile'.Hydraulic Structures and Flood Ris