The roots of the 18th century turning point in earthquake-resistant building

The gaiola pombalina and the casa baraccata seem to be the turning point of a gradual improvement process that, in Italy, becomes clearly recognisable after the 1703 L'Aquila earthquake. The reconstruction following that event saw the introduction of a constructional system, based on wooden elements embedded in masonry works, quite distinct from the rigorous organization of the late 18th century systems but having seemingly comparable intents. Recent earthquakes in Italy have enabled the value of that early anti-seismic technique to be recognized. In this paper we describe this technique its comparison with the systems at the end of the century and attempt to trace them back to more ancient constructional techniques attested also in low seismicity areas In these areas they seem to refer to a general attempt to rationalize masonry building's procedures whose anti-seismic potential was gradually recognized during the Enlightenment, finally leading to the Portuguese and Bourbon systems.