The devices, known as auscultation prisms, have been distributed across the facades of neighboring houses and the Seu basilica. These are used to measure millimetric horizontal and vertical movements, comparing data taken on different dates to detect any structural alteration during the excavation process.
This preventive measure is being taken before installing a perimeter screen of micropiles, necessary to isolate the work area where micro-blasting will be carried out. Micro-blasting is essential to drill the ground and extract the 6,000 m³ of rock required for the building's two underground floors.
The micro-blasting system, scheduled to begin in March, will last half a second per detonation, with a maximum explosive charge of one kilo, and neighbors will be warned with prior sirens.
The excavation will reach a depth of 12 meters, with 80% of the rock expected to be extracted using micro-blasting. The blasting phase will be managed by the Manresa company Pervosa, while the construction is handled by Cots i Claret and Certis.
The future Generalitat headquarters in Central Catalonia, costing 22 million euros, will be erected between the streets of la Codinella, Galceran Andreu, and Baixada de la Seu. The planned duration of the works is 30 months, following the laying of the first stone last October 11.
