ABSTRACT
The development of Terreiro do Paço Square began after the 1755 Lisbon earthquake, with the construction of the eastern side buildings. On the western side, an embankment had to be built first, in an area previously occupied by the river, overlying the existing soft soils. The western tower was constructed later, overlooking the Tagus River, and was not completed until the mid-nineteenth century. In 1941, a Portuguese historian reported that this tower had suffered a settlement of more than 0.5 m. Between 1956 and October 2019, the southeast and northeast corner's settlement increased by 0.15 m and 0.11 m, respectively. Interestingly, no damage was found on the external walls or the arched ceiling of the first storey, indicating a rigid body movement. More recently, the Lisbon Municipality sought to extend the Lisbon Museum by placing one of its modules in the newly vacant western tower. Using the finite elements approach and a three-dimensional numerical model, stress and strain studies were carried out with the purpose of analysing the effect of the rehabilitation works on its safety and functionality. Because of the period since the tower's completion and the permeability of the muddy soils in its foundation, a soft soil constitutive model with creep was used to simulate the ongoing settlements, with satisfactory results. This allowed for a more reliable prediction of future settlements caused by the tower's new usage.
