Seismic vulnerability assessment of timber roof structures: criteria and procedures

Timber roof structures have a strong influence on the behaviour of masonry buildings during earthquakes. In a seismic event, they may link walls and favour the development of a positive global response or they may suffer damage that can extend to masonry elements. From the perspective of risk mitigation, basic criteria and procedures for assessing the seismic vulnerability of timber roof structures are needed. After extended research, the main factors determining seismic vulnerability in such structures were identified. The steps of an assessment procedure developed within the research programme are discussed in this paper. The procedure comprises initial visual inspection for collecting data and information on the main parameters that are significant in seismic conditions, and their subsequent classification according to a grading system. Structural criticalities are thus identified, which may possibly be reduced. In the applications and case studies performed so far, the procedure has proven useful for focusing attention on the seismic qualification of timber structures that were originally conceived with regard to vertical loads.