Structural Rehabilitation of Vaults in Heritage Asset Learning: collapse identification and design of compatible strengthening systems supported by adaptive 3D models

The structural strengthening of heritage assets is a leading sector in many European countries, including Italy, where there are high percentages of ancient masonry buildings provided with curved horizontal structures with complex geometry. REVHEAL will focus on the safety assessment of cross masonry vaults and the design of risk mitigation strategies in compliance with the traditional conservation criteria. The project will analytically identify the collapse mechanisms by using innovative technologies supported by 3D user-oriented digital models. Two main objectives will be achieved. First, a methodology for the detection and classification of the expected failure mode of cross-vaulted structures will be proposed. Second, appropriate risk mitigation strategies will be proposed, through the design and modelling of suitable reinforcing systems aiming at preventing structural collapses and loss of human lives. Focus will be given to natural Textile Reinforced Matrix (TRM) composites and their mechanical properties, whose understanding represents an open issue. REVHEAL will start from some preliminary numerical studies performed on masonry cross vaults with radial and diagonal patterns. These studies apply to some limited cases of vaults with dry joints and blocks not experiencing internal crushing. Then, an experimental campaign on small-scale vaults will be performed to validate the existing models and develop new models related to vaults that can experience failure either along not-aligned joints or within the voussoirs. The project will also provide the validation of the proposed models through real-scale tests on two pilot masonry cross vaults subjected to cyclic shear loads. The two vaults will have radial and diagonal brick patterns and will present the backfill at the extrados. The test on each vault will include two stages. The former will aim at loading the not strengthened vault till the attainment of a significant damaging condition; the latter will investigate the behaviour until failure of the pre-damaged vault after repairing with natural TRM systems. The experiments on both scale specimens will be supported by 3D digital models based on accurate point clouds and multi-scale approximated surface objects. Advanced technologies and methods for data acquisition and parametric modelling strategies for approximation will be proposed and validated. The latter will allow to investigate the relationships between model accuracy and suitability for FEM performance estimation. REVHEAL will lead to the proposal of abacuses and guidelines for both assessing static and seismic risk scenarios and determining proper strengthening interventions. High-level approximation models for predicting the capacity and ductility improvement of strengthened vaults will be also proposed. Finally, REVHEAL will validate the proposed approach against the case study of the Palazzata of the Santuario Regina Montis Regalis in Vicoforte in Italy.