Organic and Inorganic Overlapping in Old Barcelona

Barcelona’s rapid growth prompted by the Cerdà Plan produced a fast expansion on the nearby plane, whilst the urban patterns in the Ancient City were left aside, owing partly to differences in economic protocols applicable to the planning process in both areas that neglected its complexity for decades. A layout of narrow alleys and high density characteristic of the old quarters was pointed out as the cause of decay, low hygiene, misery and delinquency, together with low income rates and marginality, for which a change was sought through several plans. The opening of new ways altered the medieval pattern of streets, lines of growth, connections to the old city core and removed commercial and gathering centres, whilst fostering new organic patterns. The tendency towards rational global planning affected the Ancient city leaving aside the local scale, where we find a recurrent design tendency to solve through clearance. An apparent conflict is then present when dealing with different layouts developed according to different logics: an organic layout and a sort of collage city that must come to terms with tracings produced for a larger, metropolitan context. Which has been the effect of these changes regarding the urban patterns? Cartography from 18th and 19th Century has been applied to detect and compare organic and non organic layouts of the urban grid, the city plan in the past and as it exists today, selecting the streets with higher connectivity and integration values as forming a super-grid, following their evolution in a diachronic process. Space Syntax Second order measures (intelligibility and synergy between local and global scale) are then applied to the processes. Correlation values and regression lines are studied and evaluated, isolating only the main old lines of access in the initial stages that have persisted in later development, so that the different states are counterpoised, comparing values of regression for the whole area (global) and for the lines selected, so that we can evaluate how their contribution to the overall layout changes through time. We also take into account the nature of the local and global measures concerning urban centralities or patchworks given by the urban system and its trend uses; a second reading of the first set of values can then be obtained, questioning the consistency between real centralities and trivial ones,as well as the relation and limits of the different metric and topometric radii. Proceedings: Eighth International Space Syntax Simposium. Santiago, PUC, 2012. PAPER REF # 8035 2 The comparison of integration and intelligibility detects alternative patterns of movement, their relation with new centralities, and empirical data to contrast research advanced by other authors. The old core or super-grid can be seen quite clearly, suggesting the relevance to maintain and improve its integrative qualities from which the whole area can benefit, throwing some light on the superimposition of organic layouts and recently planned interventions that aimed to preserve the urban qualities. Proceedings: Eighth International Space Syntax Simposium. Santiago, PUC, 2012. PAPER REF # 8035 3