Pombaline cage (anti-seismic timber frame)
Gaiola pombalina (entramado antisísmico)
- Date
- 1755-1777 · confidence medium
- Place
- Baixa Pombalina, Lisbon, Portugal
- Credited to
- Manuel da Maia, Eugénio dos Santos and Carlos Mardel, under the Marquis of Pombal
- Field
- Tools
⚠️ Disputed: the sources disagree.
What it is
A timber frame of St Andrew's crosses embedded in the masonry walls of the buildings of the reconstruction of Lisbon, absorbing the shocks of a new earthquake. It is considered the first systematic anti-seismic system in European construction.
It is debated whether the gaiola was conceived in response to the earthquake: timber frames existed in Lisbon before 1755 and the legend of tests with troops marching around models is undocumented. Its real seismic performance is now being studied with laboratory tests.
What it led to
- reconstruction of the Baixa with a regular layout and firewalls
- building regulations with seismic criteria in the 18th century
- modern study of earthquake-resistant timber-frame structures