This thesis discusses the relations between form and norm in the materialization of the cities and the pragmatic contemporary urbanism, in its most commonly discussed mode: the urban project. The urban project is here understood as the mediating elements of urban transformation, which today lack of theorization and instrumentalities in the Brazilian context. Through the dialectic relation between theoretical discourse and empirical observation, the materialization of the contemporary city is discussed, by means of the conceptual figures Definition, Induction and Improvise, which are related to processes triggered by regulations. The floodplain of Tietê, between Lapa and Barra Funda, located in the west region of the city, between the river and the rail, is used as empiric object, site which generated the theoretical reflections, and was evaluated as in its historic materialization as in its contemporary redevelopment. The work offers a spatial historiography of the sites materialization, by means of the elaboration of conceptual formal figures, which guided the historic materialization process, and evaluates the contemporary materialization, guided by the instrument Urban Operation, conceived to promote urban projects in the city. Departing from the thesis that the contemporary urban projects, in order to materialize according to socially agreed goals, has to incorporate urban design strategies in its conception, this research discusses the role of the urban project and urban design in the materialization of São Paulo.