Since the early 2000s, a specific monitoring of the Francisco Silvela bridge had been carried out due to its special disease. This monitoring was framed within the tasks carried out by the Madrid City Council and more specifically by the Department of Equipment and Road Works.

The bridge had been subjected to periodic inspections, tests and complex analytical and repair works that had been intended to delay the evolution of the disease that had the concrete, basically a strong process of aggregate – alkali in its concrete.

During the first months of 2020, it was possible to confirm the evolution of the damage caused by the aggregate-alkali and the presence of ettringite in the concrete. Once the incidence of these two chemical processes on the mechanical properties of the concrete, the existence of a very high level of prestressing and the impossibility of stopping the phenomenon had been analyzed in depth, it was decided to dismantle the structure.

The challenge was great as it was necessary to dismantle a bridge of more than 450m long and 15.00m wide, in an urban environment (minimizing noise and dirt), interfering as little as possible with the traffic in the area and not generating more, and finally at high speed to restore both pedestrian and vehicular traffic, since the bridge had to be shored in its entirety due to its condition.

The works began in July 2020 and were completed in November of the same year, were carried out by Dragados and INES Ingenieros was in charge of construction management.