This chapter suggests that an extension of the capability of the traditional inplane macro-models to capture the simultaneous in-plane and Out-Of-Plane (OOP) response of infills. A new simplified macro-model for the assessment of both in plane and out-of-plane responses of infilled frames was developed and validated. The possibility to simulate the arching action is achieved by using distributed plasticity fiber-section elements, able to directly account for the coupling between axial load and bending moment. The arching action is explicitly introduced by the use of fiber-section beam-column elements, which can model the coupling between axial-load and bending moment. The model presented is able to predict simultaneously the In-Plane and OOP response explicitly accounting for arching mechanism and two-way action. The OOP tests were carried out by inflating an air bag enclosed by a reaction panel and monitoring the response in terms of force and displacement of the mid-span joint.