A Proposal for a Procedure to Evaluate the Seismic Vulnerability of Historic Timber Frame Buildings

Abstract

The seismic vulnerability of historic timber frame building heritage is difficult to quantify in retrospect. However, in order to maintain, restore or even retrofit these buildings, it is indispensable not only to understand their performance under an earthquake loading, but also to gain quantitative information on stiffness, load bearing capacities and failure modes of the used timber frame technique. A possibility to assess earthquake behaviour is full-scale testing, but this is very expensive and it is nearly impossible to cover all the different timber frame systems, the variations between the different systems and different earthquake loadings. Therefore, small-scale tests on components or substructures are more suitable whose outcomes can be used for nonlinear dynamic modelling of buildings. This contribution proposes a simple testing-modelling approach to quantify the seismic vulnerability of timber frame buildings. The testing includes monotonic and quasi-static reversed cyclic tests on shear walls which are re-built specimens mirroring as exactly as possible the historic archetypes for both wall dimensions and used materials. The test results are then used to develop nonlinear dynamic lumped mass models which are subjected to various earthquake accelerograms. By increasing the single earthquake’s peak ground acceleration (PGA) values, the seismic performance of the investigated historic structure can be evaluated and suggestions can be given with respect to restoring or retrofitting measures. On the basis of a valid and reliable mathematical model, also parameter studies varying, for instance, the number of fasteners in joints are more readily carried out than with experimental methods.