Numerical simulation of creep and shrinkage in widened concrete bridges

Creep and shrinkage of concrete can cause cracking or damage when original old bridges that are widened directly by new bridges in a lateral direction experience constrained stress and deformation. This paper presents a numerical method to evaluate creep and shrinkage based on Newmark's methods. In addition, an example of an actual bridge widening process was analysed to obtain displacement and stress redistribution and compared with calculations from a finite-element method. The results validate the precision of the numerical method and show that the displacement of the new and old bridges, as well as the stress exerted on them, will not lead to concrete cracking. However, creep and shrinkage make significant contributions in the first 3 months and therefore it is suggested that bridge widening is carried out when new bridges are 3 months old.