Integrated Dating of the Construction and Restoration of the Modena Cathedral Vaults (Northern Italy): Preliminary Results

ABSTRACTAfter the last damaging earthquake in 2012, an anti-seismic reinforcement project of the cathedral of Modena was designed giving us the opportunity to investigate and date the building materials. Radiocarbon (14C), optically stimulated luminescence (OSL), and thermoluminescence (TL) dating techniques were performed on the vaults with the aim to (1) clarify the construction timing, (2) define the history of the restorations, and (3) explore the possible correlation of the main restoration works to the earthquake chronology deduced from the historic catalog. Preliminary results show that medieval older bricks were reused for most of the original construction. Only lime and non-gypsum mortar was used for the original construction in the 15th century and for later repair of damage caused by earthquakes in the 16th and 17th centuries. Gypsum mortar was used for later repair in the 18th century. The results show much stronger damage due to earthquakes than previously thought.

Enhancing heritage fruition through 3D virtual models and augmented reality: an application to Roman artefacts

<p>The spatial characteristics of museum exhibitions may limit visitors’ experience of the artefacts on display. In the case of large artefacts, limited space may affect their whole visualization, or inhibit the visualization of the details farthest from the observer. In other cases, the storage of artefacts in distant sites (museums or archaeological areas) may influence their knowledge process or the possibility for comparative analysis. Moreover, the precarious state of preservation of some artefacts, with damaged or missing parts, makes it difficult to perceive their original appearance. To overcome these limitations, we propose an integrated approach based on 3D virtual models and Augmented Reality (AR) to enhance the fruition of artefacts, improving their visualization, analysis and personal/shared knowledge, also by overcoming space and time constraints. The final AR application is an easily accessible tool for most users from a mobile device, used both inside and outside museums, opening new perspectives for fruition. The framework encourages the use of free and open source software and standard devices, to maximize their dissemination and exploit the potential of such technologies, which is far greater than current use in the cultural heritage field. Selected case studies to test and validate the integrated framework are proposed, dealing with some Roman artefacts found in the area of Modena (Italy). The first is a Roman floor mosaic, found in Savignano sul Panaro (near Modena) in 2011, of which less than half of its original 4.5 x 6.9 m surface is preserved. The others are two Roman funerary lion sculptures: the first is one of two lions flanking the main door of Modena Cathedral, and the second, well-preserved but damaged, is housed in the Museo Lapidario Estense of Modena. Finally, the application was tested by museum experts and visitors both inside and outside the museum, and positively assessed.</p><p><strong>Highlights:</strong></p><ul><li><p>Digital practice is not understood as a prerogative of a small number of people, but as a tool to guarantee and expand artefact fruition, using standard devices and free and open source software.</p></li><li><p>Experimentation of new settings to re-contextualize artefacts and establish possible links among them, offering engaging and customized experiences to improve their accessibility and enjoyment.</p></li><li><p>Promotion of artefact fruition not only in but also outside museums, such as in a classroom or an open and shared space, opening to new approaches in the fruition of cultural heritage.</p></li></ul>

QUALITY FEATURES FOR THE INTEGRATION OF TERRESTRIAL AND UAV IMAGES

<p><strong>Abstract.</strong> The paper presents an innovative approach for improving the orientation results when terrestrial and UAV images are jointly processed. With the existing approaches, the processing of images coming from different platforms and sensors leads often to noisy and inaccurate 3D reconstructions, due to the different nature and properties of the acquired images. In this work, a photogrammetric pipeline is proposed to filter and remove bad computed tie points, according to some quality feature indicators. A completely automatic procedure has been developed to filter the sparse point cloud, in order to improve the orientation results before computing the dense point cloud. We report some tests and results on a dataset of about 140 images (Modena cathedral, Italy). The effectiveness of the filtering procedure was verified using some internal quality indicators, external checks (ground truth data) and qualitative visual analyses.</p>

In Situ Investigation of the Mechanical Strength of the Mortars: The Case of the Vaults of the Modena Cathedral

The 12th C. Modena Cathedral is a masterpiece testimony of early Romanesque architecture, artand civic values of the time. Following the inclusion in the UNESCO list in 1997, studies, surveysand maintenance works have started. The Emilia’s seismic events of May 2012 have happenedwhen the maintenance operations were already in an advanced phase. The quakes caused damageand re-opening of some historical cracks, in particular in the thin vaults of the naves, near thefaçade and at the junction between naves and choir and crypt. Fragments of brick, mortar from thejoints between bricks and even limited portions of a diagonal rib have fallen to the ground. In viewof seismic assessment and strengthening for improvement of the structural behaviour, detailedstudies of the vaults’ mortar became necessary. The investigation approach was minimal andpreservative, combining on-site close-up visual inspections and micro-destructive testing of themortar joints by mortar penetrometer. For this purpose, openings of 0.25x0.25 m2 in the renderlayer of the 23 vaults were created. The outcome has allowed differentiating between repair mortarsof different strength, used in different historic periods. The mortar resistance was very low butdifferent for lime mortar and gypsum. Values, divided in 3 classes of strength, were found tocorrelate well with the location and severity of the crack pattern and damage map in the vaults. Theresults were useful for a correct design (minimal and reversible) of the cathedral strengtheningintervention.