Seismic evaluation of pombalino buildings

An original anti-seismic constructive system was elaborated after the earthquake that destroyed Lisbon on the morning of November 1, 1755. This technology consists of a tri-dimensional timber frame structure - called gaiola - composed by vertical panels and horizontal beams. Small stones and limestone mortar fill the gaps between the timber elements. The internal structure of the new building – referred as Pombalino - is entirely constituted by this timber frame, whereas the perimetral structure consists of thick masonry walls. In the case of an earthquake, the masonry walls may collapse, but the interior frame was supposed to resist with minor damages. A simple methodology for the seismic analysis of this type of buildings is proposed in the present paper. A late Pombalino building is investigated and a seismic safety evaluation is carried out by means of modal analysis, push-over analysis and kinematic analysis. Connections between timber elements themselves and between timber elements and masonry walls are the most critical aspect of modeling. The building shows good in-plane behavior but it results vulnerable to local modes of collapse.