What one needs to know for the safety assessment of timber structures. Is there a need for guidelines?

Abstract

The strength and safety assessment of old timber structures are normally a great source of problems for building interventors and a frequent justification for integral replacement of structures that would otherwise be kept in service.

It requires understanding the original structural system behaviour, the estimation of strength and stiffness properties of the timber in use, the evaluation of individual timber members’ quality and effective cross section dimensions. Due to the natural variability of timber, unknown load and environment history, and common biological damage, assumptions have to be made, frequently with a high degree of uncertainty.

This paper discusses the common approach in the strength assessment of timber structures in service and identifies current problems, knowledge gaps and research needs. The possibility and opportunity of developing guidelines and standards relating this activity will also be addressed.