Tradycyjne zabezpieczenia antysejsmiczne na przykładzie cytadeli Casbah w Algierze

In the years 1983-1986 the State Ateliers for the Conservation of Cultural Property made up a program for the restoration of the Casbah Citadel in Algiers. The work on the program was preceded by complex studies, particularly of the old anti- seismic protection measures. In this article the authors present their observations, which do not exhaust the issue. They are as follows: 1. The construction is located on a rock massif. 2. There is a considerable amount of mutually perpendicular bearing walls in the citadel. 3. Over each capital of a column or pillar there are 3 -4 layers of short ovolos of thuya wood. 4. In certain bearing walls the wooden ovolos have been walled in 3 -4 layers at the height of the storey. 5. The bearing walls have been made of full ceramic brick, 3 -5 cm thick, and generally with lime mortar, ground brick being added as filler. On the basis of historical accounts it can be stated that the applied construction methods, chosen on intuition and from experience, not following theoretical analysis, have proved correct (particularly during the strong earthquake of 1716).