In the Telemac-Mascaret community, there is an increasing need for Telemac-3D to handle unstructured 3D meshes. One of the main target applications is the simulation of submerged structures in the flow. With this aim in view, a first step is to modify the code so that it can account for vertical structures on the bed. This is done while maintaining the advantages of the layered 3D meshes currently used in Telemac-3D, since a full destructuration would imply more complex neighbour searches, data access and would require major changes in the algorithms. The proposed approach will be presented in this article, including a description of the necessary developments, comparisons of CPU time before and after the changes, and a qualitative test case.