Since 1980, Pietrangelo has been an active volunteer for the reuse and enhancement of fortified sites located in the Venetian mainland. He started constituting several associations aimed in the management of the fortified complexes of the 1800s belonging to the so-called Campo Trincerato di Mestre. Pietrangelo also coordinated the work of many of associations in order to re-use the Piazza di Difesa Marittima of Venice.
Pietrangelo was a municipal councillor at the Municipality of Venice and delegate of the Mayor Prof. Massimo Cacciari. Thus, he considerably contributed to the enhancement plan of the fortified complex-buildings.
Particularly, Pietrangelo was actively involved for the recovery plan and re-use of the Fort Marghera, a fortified building of 40 hectares dating back to the Napoleonic period and located between Mestre and Marghera. There he created a Study and Documentation Centre for the Defence Systems.