Timber anti-seismic devices in historical architecture in the Mediterranean area

Abstract

This work investigates the exploitation of a historical timber device used as masonry reinforcement in seismic prevention in the Mediterranean area. Such a technology is realized by means of a three-dimensional timber frame embedded in stone masonry in order to bind together the various structural parts, and contribute to the overall seismic resistance. Very often, such a constructive principle was extended not only to the weakest parts but to the whole building, creating new structural configurations that were able to absorb the effects of seismic ground motions. From Roman times (opus craticium), this system spread all across the Mediterranean area becoming common during the eighteenth century in Italy (Bourbon casa baraccata), in Portugal (Pombaline gaiola), in Turkey (hımış), etc. However, examples of timber devices and frameworks may be found almost worldwide: in the continental northern Europe, including those countries that are usually not subjected to earthquakes, as well as in Central Asia or in Japan, to America and North Africa. A large number of examples are reported to show how some traditional technologies, along with the suboptimal rules of the art, made a robust construction possible. Furthermore, by means of philological criterion and detailed analysis of seismic vulnerability improvement, the knowledge of such a system may allow developing novel designs and specific preservation works that could ensure the structural safety of historical constructions without modifying their main structural configuration. From such a perspective, this study examines the aspects of using diffused timber frameworks with masonry infill that go beyond anti-seismic technology, describes the common constructive features and helps develop guidelines for preservation of such systems.