Azores seminar on stone housing - seismic culture

1. The use of building stone materials
and the favourable behaviour of
stone buildings with skeleton
structure in earthquakes
Maria BOSTENARU DAN
ERGOROM ’99
and
“Ion Mincu” University of Architecture and Urban Planning

2. Overview
 Introduction
 The morphology of historic buildings with
skeleton structure
 The behaviour of stone buildings with
skeleton structure in earthquakes
 Conclusions

3. Introduction
 Two structure types
 Solid building (Massivbau)
 Skeleton structure
 Stone buildings:
 Massivbau is typical but skeleton structure
possible (Gothic)
 This paper: stone for buildings with
skeleton structure

4. The morphology of historic
buildings with skeleton structure
 Gottfried Semper: theory of clothing
wall-floor-ceiling typology
 Semper never employed his theory, this
was done by Viennese architect Otto
Wagner – sincerity in architecture
 Morphologic analysis: two elements
 Load bearing structure
 Contents

5. The morphology of historic
buildings with skeleton structure
 Between the load bearing structure and
architectural space exist:
 the structural space: historic buildings
 the free plan
 the space plan (the so-called Raumplan)
 The skeleton structure made possible a
variant of the Raumplan long before the
20th century: the Gothic (skeleton and infill
out of stone)

6. Skeleton structures out of stone
material

7. The morphology of historic
buildings with skeleton structure
 Skeleton structures with stone infill: timber
structures (half-timbered)
 Raumplan at the level of morphology

8. Materials of timber skeleton buildings in
earthquake prone regions
Alps Portugal
Infill adobe sandstone
Skeleton oak
(sometimes fir)
fir and oak
Roof oak fir and oak
Floor oak fir and oak

9. Characteristics of the building materials in
residential buildings with timber skeleton in
the Alpine region
Structual
Element
Construction
materials
Resistance characteristics Mix / dimensions
Wall
Infill
adobe
oak timber
planks
For further information regarding the adobe infill, see:
http://www.fachwerkhaus.de/fh_haus/info/fsan.htm
(2004).
Skeleto
(histori
buildings)
oak
(sometimes
fir)
Elasticity modulus 6.9-11.8 GPa;
tension 128 MPa;
compression 50 MPa;
bending 100 MPa; shear 77
MPa
Skeleto
(new
buildings)
douglas fir
or
Laminated
wood
Elasticity modulus 7-14.1 GPa;
tension 25.0 MPa;
compression 10.8 MPa;
bending 84 MPa; shear -
Lower horizontal elements: 13/18, 13/20, 15/20, 13/21 or 16/21
cm (Stade, 1904). Upper horizontal elements: 12/12,
13/13, 12/14, 13/15, 13/18 cm. (Stade, 1904) Corner
pillars: 13/13, 15/15, 13/16, 16/16, 21/21 cm (Stade,
1904). Intermediary pillars:12/12, 13/13, 12/14, 13/15,
12/16 or 13/16cm (Stade, 1904). Diagonals: 12/16 or 13/18
cm (Stade, 1904). Upper horizontal elements (sustaining
the roof): 12/16, 13/18 or 16/21cm (Stade, 1904).
Floors oak timber see above Planks are 2-5 cm thick. The joists are between 2.5cm (0.80m
span) to 16cm (4.5m span)
Roof oak timber see above Timber between 8/8 cm and 28/30cm. (Stade, 1904).

10. The morphology of historic
buildings with skeleton structure
 Evolutionary structural optimisation
 the original structure reaches the optimal
shape eliminating the non-effective
elements from step to step
 This theory of the 20th century, in a similar
way to that of the Raumplan, was
preceded by its practical employment

11. The morphology of historic
buildings with skeleton structure
 Gaiola pombalina:
 stone material and the timber collaborate in
such a way in the structure of a building which
can be considered the early expression of the
optimisation
 After an earthquake the exterior walls
could fall out, then also the stone infill of
the gaiola, as energy dissipators, but the
building remained staying, and so the
ones residing in it were protected

12. The behaviour of stone buildings with
skeleton structure in earthquakes
 Following the 1999 earthquakes in Turkey it
became visible that the local timber skeleton
structure buildings (himiş) behaved much better
under earthquakes
 so-called local seismic culture
 the origin for the existence of buildings with such
structure is much more caused by
 the urban way of life
 traditional “the stone house is more durable than the
timber house” concept

13. The behaviour of stone buildings with
skeleton structure in earthquakes
 The symbolics of construction materials
 The morphology of stone buildings with
skeleton structure and the ship structure

14. The symbolics of construction
materials
 English folk story: The Three Little Pigs
 the grass house can be the symbol of the
collecting population, the timber house of the
half nomads and the stone house of the
settled one
 the straw house is finished more quickly than
the stone house, for the building of which it
must be worked much more, and there is less
time left for play, for distraction

15. The symbolics of construction
materials
 Romanian greeting for wedding is “casă
de piatră”, which means house of stone
 the stone bridge is taken away by the
water, and a newer one, more durable and
more beautiful will be built further down
along the water, where the water is deeper
and more dangerous

16. The symbolics of construction
materials
 Apart from the ideologisation the stone
house, since it was done with more work
and for more money it was foreseen for
richer layers of the society.
 fires destroyed the towns more often in
former centuries than earthquakes, which
were unexplainable and thus could be
rather considered the will of God

17. The symbolics of construction
materials
 Some timber houses resisted centuries
(700 years)
 Resisted better to earthquakes but not this
is the reason why they spread

18. Residential buildings with timber skeleton
load bearing structure in earthquake prone
Basel, Switzerland Lisbon, Portugal

19. The morphology of stone buildings with
skeleton structure and the ship structure
 there is an interdependence between the
metaphor of the ship and the engineering
forms
 2 levels
 Façade
 Interior space

20. The morphology of stone buildings with
skeleton structure and the ship structure
 the buildings with timber skeleton are not
typical for earthquake prone zones but for
seaside towns and their regions
 the structure of Pombalino buildings was
inspired by ship building
 The most pure structural form of the
German Fachwerk buildings can be found
on the seaside as well, in the North (based
on a row of joists in console)

21. The morphology of stone buildings with
skeleton structure and the ship structure

22. The morphology of stone buildings with
skeleton structure and the ship structure:
facade
 the Italian architect Marcello Piacentini
accompanied with his attention the new
Hungarian architecture from the turn-of-
the-century

23. Ship structure in the façade:
Hungary

24. Ship structure in the façade: Italy

25. The morphology of stone buildings with
skeleton structure and the ship structure:
interior space
 The interior space comes close to the ship
metaphor from the structural point of view
 the interior partitions of the churches are
called naves
 In the Gothic buildings the structure of the
ceiling of the naves was shaped according
to the rules of the ships. This structure
with a spatial effect (3D) is common with
that of the ships, but also with the
buildings with timber skeleton

26. The morphology of stone buildings with
skeleton structure and the ship structure:
interior space
 the height of the Gothic churches > their
wind load is considerable and the structure
similar to a ship was designed to resist
these loads
 Such a structure proved correspondingly
resisting facing earthquakes, since the
earthquake forces act also horizontally
and wave-like

27. Conclusions
 The use of the morphology proved suitable
to unveil the spread concepts of the so-
called local seismic culture.
 According to the folk story the stone material
offers the biggest safety.
 The 1755 earthquake, which affected Lisbon,
proves the opposite.

28. Conclusions
 Under the marquis of Pombal the stone
walls are reinforced with timber skeleton
structures
 also in the Gothic buildings which inherited
the cage structure: the stone is both
skeleton and space limit, structure and
ornament, it plays a role in all elements of
the morphology as a material

29. Acknowledgements
PIANO project
Marie Curie Reintegration Grant
MERG-CT-2007-200636

30. Thank you!