# Abstract

Damage models are often used in finite element simulations of concrete structures. Evaluating the numerical quality of these computations consists in an important task which can be performed by using an error estimator. However, in the framework of nonlocal approaches these estimators seem to be much less abundant in the literature and their implementation requires considerable efforts. In this paper, a new error indicator with relatively less difficulties for its implementation is proposed. Based on local and least squares smoothing techniques, the convergence analyses of the developed indicator is carried out and discussed. The obtained results seem to be in good agreement with those obtained by the use of residual method. In addition the major difficulty to obtain an automatic step-by-step mesh adaptation is highlighted. Nevertheless for a chosen loading step, optimized calculations can be performed and example tests are presented.

**Keywords**

FE analysis -concrete- nonlocal damage; error indicator; least squares smoothing; error convergence rate; step mesh adaptation