Is Nonlinear Analysis Becoming a Standard Tool for Design and Assessment of Reinforced Concrete Structures?

The nonlinear finite element method has become a standard tool serving engineers during the designing of reinforced concrete bridges. Compared to a linear solution, the main advantage is that it can provide a better insight into the realistic material response including crack formation and subsequent redistribution of internal forces. In this paper, the key aspects related to the application in engineering practice are summarised, including the theory behind the nonlinear material model and the explanation of the solution method. Based on validation against experimental data, the accuracy of a given nonlinear tool can be quantified and translated into a model partial safety factor. This factor then serves as a parameter in the evaluation of the design structural resistance. Finally, we show an example of an assessment of a post-tensioned reinforced concrete bridge, where strengthening provisions were adopted to reinforce a critical region with crack formation.