Despite being a well-known monument, the Roman amphitheatre of Tarragona, which is included in theUNESCO World Heritage List, was only fully studied in the late 1980s. The study was therefore subject tothe archaeological research limitations and specific characteristics of that time, as can be seen in the qual-ity of the site’s planimetry. The general planimetry was basically available for relevant sections at a scaleof 1:100 with sufficient accuracy. However, according to current scientific parameters, this planimetryis clearly inadequate, and cannot be used rigorously to obtain comprehensive architectural knowledge.The technical limitations of the time, and the innate difficulties presented by the monument, meant thatonly a few sections were obtained, specifically two, with a low level of detail. This has led to misinterpre-tations, and consequently to dubious or erroneous conclusions. Therefore, the need for complete metricdocumentation is evident, as this will enable us to correctly analyse the monument. We have obtainedmetric documentation by carrying out a topographic survey using digital photogrammetry, which pro-vides us with more information than merely measurements. We can use the three-dimensional modelthat was generated to analyse the sections of the stands and draw conclusions about their geometry.Peer ReviewedPostprint (author's final draft

Toda obra arquitectónica necesita de una proyección previa que implique la definición y justificación de sus formas y proporciones, proyección que, a menudo, viene modificada por la realidad ya existente o, en casos de periodos constructivos largos por cambios de opinión, de finalidad o, incluso de promotor. Es el caso del Concilium Provinciae Hispaniae Citerioris de Tarraco, un gran complejo monumental de más de 12 hectáreas de extensión, que necesitó un periodo de tiempo de construcción de entre 70 a 75 años. Los restos arqueológicos conservados permiten la identificación de dos proyectos arquitectónicos sobrepuestos que implican un profundo cambio de proyecto durante el proceso constructivo.

Las nubes de puntos son objetos con un incuestionable valor geométrico. Pero el desarrollo de determinadas metodologías de trabajo permiten extraer de ellas información que va más allá de la métrica, permitiendo análisis semánticos del objeto documentado. En este trabajo exponemos una de estas metodologías que consiente, únicamente modificando la visualización de las nubes de puntos, poner en evidencia elementos de valor semántico del objeto arquitectónico escaneado.

The use of massive data capture techniques in architectural heritage has enhanced the development of new methodologies that have an important impact on their conservation and understanding. The research proposes the study of formal anomalies in the cloister of the Cathedral of Tarragona (c. 12th century). It is a relevant Gothic construction in Catalonia, with the special singularity that part of its structure is raised over an important pre-existing Roman wall. The investigation is based on a point cloud obtained with a terrestrial laser scanner (TLS) and the systematization of the 3D analysis methodology of the point cloud through different reference shapes. In general terms, the construction is in good condition, so the discrepancies between real construction and the shapes of reference are small, with some exceptions. Nevertheless, the different approximations used allowed us to identify some relevant features, such as the variability of the form of rib vaults, and the influence of the criteria used in the definition and location of reference forms.

The Mediterranean city of Tarragona was a capital city in Roman times. Nowadays, the remains of the ancient constructions coexist with many subsequent buildings. This is the case of the Gothic Cathedral cloister, whose walls partially take advantage of the remains of the temenos's wall. This paper focuses on the assessment of that unique overlapping of construction phases. The investigation is performed through an unprecedented topographical survey by means of massive data capture techniques. This information is the basis for the mechanical assessment of the equilibrium conditions of the northern corner of the gallery, which is performed on the well-known theoretical framework of limit analysis by means of thrust lines. The study allowed to enhance the understanding about the equilibrium conditions and the deformation processes of the gallery masonry elements, where the mechanical relation between the Roman and Gothic walls is essentialPeer ReviewedPostprint (author's final draft