Influence of Various Light Timber Retrofit Layouts on the Dynamic Response of Typical Duch Masonry Terraced Houses

Abstract

A majority of the residential building stock in Groningen (The Netherlands), which has been lately exposed to low intensity ground motions due to gas extraction, consists of unreinforced masonry (URM) structures not originally designed to withstand earthquakes. Amongst them, the terraced house building typology proved to be particularly vulnerable towards horizontal actions. Experimental results from a recently performed shake-table test on a full-scale terraced house prototype, characterised by the presence of a timber retrofitting system, seem to indicate that the dynamic response of these structures might be consistently improved through the employment of such a cost-effective light retrofitting solution. In this work, an advanced discontinuum-based model, implemented in the framework of the Applied Element Method (AEM), is developed to extend experimental results and to numerically investigate the influence of a number of additional timber retrofit layouts, characterised by different geometrical configurations, on the building behaviour. Each timber component was explicitly represented in the AEM models to represent the possible interaction among URM walls and the retrofitting system. First, the proposed modelling strategy is validated against experimental tests on both non-retrofitted and retrofitted URM panels subjected to cyclic shearcompression loading. Then, calibrated mechanical parameters were directly implemented in the full-scale building model. Given the good agreement between numerical and experimental outcomes in terms of both damage evolution and hysteretic response, a comprehensive parametric study was undertaken. Numerical evidence seems to suggest that the employment of different retrofit layouts may have a significant influence on the dynamic behaviour of the selected building typology.