The safety of large civil structures is often evaluated by means of numerical models based on the Finite Element Method (FEM). In this frame, the choice of a constitutive law able to represent the complex mechanical behavior of concrete is a key point. The classical approaches, whose theory is formulated in terms of stress and strain tensors and their invariants, are generally able to simulate in a proper way only a few specific characteristics of concrete, but they often present a limited capacity to reproduce the overall material behavior. A promising approach to overcome this limit seems to be the Microplane Model whose basic idea is related to the observation that the main mechanical phenomena of concrete take place on planes whose orientation depends on load and material conditions. This paper deals with a detailed description of the implementation process followed to insert the elastic part of the Microplane Model within COMSOL. The examples used to validate this part are presented as well. The implementation of the non linear behavior of the Microplane model is still in progress; therefore it is not addressed in this paper.