This article presents an extension of the branch Eigenmodes reduction method (BERM) to substructuring models. One of the method's interests lies in its capacity to build a reduced modal model for complex geometries which are characterized by very large matrix sizes. This article treats a 3-D nonlinear application. Such a substructuring reduced model permits us to obtain precise results over the whole domain, with an important gain of CPU time. In the case considered, a global reduced branch model can also be built. A comparison between the two reduced models shows the interest of the substructuring technique.