Seismic performance of ancient timber-framed walls
Leonidas Alexandros Kouris1, prof. Andreas Kappos1
1
Department of Civil Engineering, Aristotle University of Thessaloniki, GR
The incorporation of timber elements in the body of unreinforced masonry walls was frequently used in the past to
increase their capacity against seismic actions [1]. Besides, a more light and cheap construction was developed in
regions with high seismicity; the timber-framed wall. Thin walls with the effective insertion of horizontal, vertical
and often diagonal beams can be found even from the Bronze Age [2] and the roman “opus craticium” (Fig. 1)
described by Vitruvius on his book “De architectura”. Diagonals are often used in the structure in order to increase
lateral stiffness and strength (Fig. 2). In this paper the seismic performance of these constructions is investigated
and an inelastic model is proposed.
The nonlinear static methodology is adopted for the estimation of the performance of these structures under
lateral loads. The main target of the model is the estimation of the inelastic behaviour of the structural members
of the building. In the present work, a 2D nonlinear static analysis is performed on a large wall (2.55×3.42m)
consisted of six panels. Main sources of nonlinear behaviour of timber framed masonry structures are (i) the slide
over the connections of timbers elements subjected to tension loads, (ii) the nonlinear behaviour of masonry infills
(cracks) and (iii) the nonlinear interaction between timber elements and masonry infills. Considering all these
sources, a sophisticated model is developed including a plasticity law for the unreinforced masonry infill, a
plasticity law for the timber elements and a interaction law for the connection between timber elements. This
analytical model is compared with laboratory results.
Furthermore, for the analysis of common buildings (Fig. 2) a simpler model is proposed consisting of beam
elements. This model incorporates point hinge using a N (axial load) – d (axial displacement) curve in the diagonals
of the frames. The derivation of the N – d curve depends on the detailed model described above.
The detailed and the simple model may be used for the analysis of buildings with timber-framed walls both ancient
of great importance as well as common heritage structures.
References
[1] A Moropoulou, AS Cakmak, N Lohvyn. Earthquake resistant construction techniques and materials on Byzantine
monuments in Kiev, Soil Dyn. Earthqu. Eng. 19 (2000) 603-615.
[2] C Palyvou. Akrotiri Thiras: I Oikodomiki Tekhni. Athens. (1999).
Fig.1 A timber-framed
masonry wall from
Herculaneum dated before
79 AD.
Fig. 2 A timber-framed
masonry construction from
Macedonia-Greece with
horizontal, vertical and
diagonal members.
Fig.1
Fig. 2