Often neglected by the practice of urban planning, this thesis explores the forms of representation of the sensitive aspects of urban life in a process of urban design. Through two field surveys we show how the inhabitants participate in the production of a creative and resilient public space. By public space we understand its double theoretical filiation: physical and political. We target the observation in the transformation processes of the public places through the modification of the practices and the meanings that these places have for the inhabitants. We also handle the public space as the place of the political debate, the meeting and the conflict in the shape of a democratic practice. This particular public space will be named: “spontaneous public space”. It is spontaneous, because it is not designed and it is not planned. As it appears spontaneously, it can disappear in the same way. It is produced from real-life experiences and from local conditions. An ethnographical field survey focused on the experiences and perception of public spaces by the inhabitants and the communities, give an intentionality to the analysis of the sensitive experience, because it does not limit itself to the dimensions of the sensitive experience but integrates what is observed or either found by inhabitants. After the earthquake and the tsunami that occurred on February 27, 2010, off the coast of south-central Chile, we noticed how in a situation of upheaval and reconstruction of the spaces of representation, the sensitive plays a key-role. The catastrophic situation generates spontaneous public spaces; it generates a practical commitment of the inhabitants, mobilizes sensitive reactions and makes the public space more hospitable and resilient. From the study of two concrete cases -corresponding to the emergency camp El Molino of Dichato and to the city of Talca after the disaster- we focus the observation in the practices of implication of the inhabitants during all the process of reconstruction of their public and private spaces as well as their intimate spheres. These practices include all the actions of the inhabitants, from their most spontaneous and short-lived actions to face the reconstruction and the state of emergency and vulnerability of the situation post-disaster, to the most formalized actions. We want to complete the idea of a “participative” urban design with the notion of a spontaneous public space - autonomous of the participative plans - as an inclusive third space capable of introducing sensitive aspects in the debate. This research gives rise to questioning the urban design as a common space of expression and understanding, where the decoupling existing between the expertise and the novice can be surpassed