The monument to Luís de Camões is located in the square of the same name in Lisbon. It is a sculptural ensemble approximately 11.5 meters high, octagonal in plan, consisting of a lioz limestone base supporting a pedestal of similar construction, about 4 meters tall. The ensemble is crowned by a 4-meter-high bronze statue of Luís de Camões, weighing approximately 4 tons.

Intervention goal

Both the base and the superstructure of the monument presented several anomalies: settlements, displacements of the pedestal stones with opening of joints, and separation of the pedestal's capping slabs. 

According to the assessment by LNEC (National Laboratory for Civil Engineering), these anomalies were attributed to deformations in the foundations, worsened by the successive seismic events that occurred over the life of the monument. Water infiltration—from rainwater through the pedestal's capping or from broken pipes in the surrounding area—may also have contributed to the observed settlements. A geotechnical survey revealed the presence of a permeable fill layer reaching depths of 5 to 6 meters, under which Miocene formations were identified. 

The consolidation work focused on both the foundations and the superstructure. 

Steps and techniques used

The initially planned intervention for foundation consolidation included the following tasks:

• Construction of a reinforced concrete slab encircling and embedded into the masonry base;

• Filling of existing voids in the underlying formations by means of injections;

• Improvement of the bearing capacity of the fill layer and the underlying sandy stratum through injections using sodium silicate-based grouts.

During these operations, it became evident that the quality of the soil beneath the monument was quite poor. It was therefore deemed advisable to complement the intervention with the installation of 16 micro-piles. 

Regarding the superstructure, once the bronze statue had been removed, it was found that the interior of the shaft was not fully filled and that the existing material was of poor quality. To consolidate the monument’s superstructure, a reinforced concrete inner wall was built near the top of the pedestal. All the ashlar stones of the octagonal shaft and the capping elements were then anchored to this new structural core using steel dowels.

After these operations, the bronze statue was reinstalled. The intervention concluded with a full cleaning of the monument.