[en] In this article, a two-stage damage identification approach is employed to detect the site and extent of multiple damage cases in a 2D frame structure. In the first stage, Damage locating vector (DLV) method based on a new indicator called EDS (Exponential decreased stress) is applied to localize the damaged elements. Next, the damage extents of suspected elements are quantified using two metaheuristic algorithms, Water evaporation optimization (WEO) and accelerated WEO. Numerical example consists of a 2D frame structure with two types of meshing elements, 35 and 105 frame elements. For every state, two multiple damage cases are tested in noisy condition. To compare performance of the two-stage method with one-stage optimization method, the studied cases are also run using these two metaheuristic algorithms. The results indicate that the two-stage approach is more effective than one-stage because the number of intact element detected as damaged one and computational errors for actual damaged elements in one-stage method are more while the two-stage approach spends a much shorter time