Reflections on the Rehabilitation and the Retrofit of Historical Constructions

Abstract

The objective of this paper is to address techniques for the seismic rehabilitation and strengthening of historical constructions, especially those that are part of old urban agglomerations, focusing attention on the existing “pombaline” buildings in the heart of Lisbon and on the traditional masonry construction inserted in urban areas of the Azores Islands. This paper further details a previous review by Oliveira (2003a, Bull Earthquake Eng 1(1):37–82) made on the seismic vulnerability of historical constructions. After an initial reference to the major damage caused to old urban agglomerations by recent earthquakes, with special emphasis on the 1980 and the 1998 Azores earthquakes, on the 2009 L’Aquila earthquake and on the 2010 Haiti earthquake, the main reasons for what has happened are discussed, and solutions to mitigate damage in future events are proposed, by focusing the attention on two construction types. The first one is the in Lisbon “pombaline” construction, consisting of a timber cage inside old masonry walls, which was developed in the reconstruction of the downtown area after the large destruction caused by the 1755 earthquake. The second case is the traditional construction in stone masonry of the Azores Islands. For each case, a brief description of the materials and of the existing construction systems is made, followed by a discussion of the various possible rehabilitation and retrofit techniques, presenting the pros and cons of each one and finalizing with a synthesis of the most effective ones.