The debate took place late last week at the premises of the Lisbon Municipal Assembly at the suggestion of opposition party CDS-PP.
The vice president of the Institute of Structural Engineering, Territory and Construction of Lisbon’s Instituto Superior Técnico, Mário Lopes, began by saying that “it is important to incorporate seismic resistance in urban rehabilitation,” or face the risk of buildings “that are deadly traps.”
In the engineer’s opinion, “the level of demand required in urban rehabilitation remains at zero,” and “this continues to be done with the complicity of the Government, the Lisbon municipal council and the entities with responsibility in the matter.”
One example is the “destruction of the Pombaline cage,” an anti-earthquake building technique, that uses a wooden structure - or cage - to reinforce brickwork walls - introduced after the 1755 earthquake that is common in buildings in the downtown area of Lisbon, the destruction of which Lopes called “a cultural crime”.
“Lisbon is the first city in the world built to withstand earthquakes, and we are destroying it ourselves,” he added.
The director of the Faculty of Architecture of the University of Lisbon, João Pardal Monteiro, gave the example of homes that are fragile because they have knocked smaller rooms together.
“We have to make people aware that we cannot make changes to this type of building without qualified technicians to do it,” said the architect, explaining that these interventions will “remove the characteristics that withstand earthquakes.”
Pardal Monteiro stressed that “interventions in the city have to be carried out with specialised technicians, so that this does not become a deck of cards ready to fall to the first earthquake.”
The debate also recalled that the first “regulation that requires the seismic calculation for buildings dates back to 1958.”
Closing the debate, the councillor for Housing of the City of Lisbon, Paula Marques, said that the municipality “has been developing several instruments in this area,” such as “updating the land chart, seismic index, and a manual of good practices in rehabilitation.”
Professor José Luís Zêzere, of the Institute of Geography and Spatial Planning, stressed that “seismicity in Portugal is moderate,” as “earthquakes of great magnitude occur at long intervals,” but nevertheless considered that the “problem is big enough to be taken into consideration.”