In situ assessment of the timber floor structure of the Skansen Lejonet fortification, Sweden.

Historical structures represent part of the cultural heritage of every nation and societies pay considerable attention to their preservation and maintenance. In historical structures, it is essential to preserve the original structure to the greatest degree possible. It is therefore of great importance to adopt structural health monitoring techniques to assess the remaining load-bearing capacity of timber structures. The main aim of this study was to examine the structural soundness and performance of the timber floor structures in Skansen Lejonet. Non-destructive testing (NDT) was used to evaluate mechanical properties and the general condition, without interfering with the structural integrity. It has been shown that the general structural condition and performance is good and fulfils the requirements for the intended use of the structure both in the past and at the present time, according to Eurocode standards. To assess the general quality of the timber, stress-wave measurements in combination with resistance drilling and X-ray measurements were applied. The quantitative evaluation of the mechanical properties and the density using stress-wave timing and radiographic measurements provided both good agreement and sufficiently good input for the structural analysis. The accurate use of non-destructive measurements, considering their crucial aspects and limitations, enables reliable results to be obtained, thereby increasing the potential to minimise interventions and prolong the service life of buildings as a part of sustainable development. (C) 2014 Published by Elsevier Ltd.

[1]  J. M. Dinwoodie,et al.  Timber, its nature and behaviour , 1981 .

[2]  Paulo B. Lourenço.  ASSESSMENT, DIAGNOSIS AND STRENGTHENING OF OUTEIRO CHURCH, PORTUGAL , 2005 .

[3]  Keith Crews,et al.  In situ assessment of structural timber using stress-wave measurements , 2014 .

[4]  Francesco Augelli,et al.  In situ assessment of structural timber using non-destructive techniques , 2014 .

[5]  Robert Kliger,et al.  Assessment of Density in Timber Using X-Ray Equipment , 2013 .

[6]  Maurizio Piazza,et al.  Structural analysis of two King-post timber trusses: Non-destructive evaluation and load-carrying tests , 2010 .

[7]  G. Í. González,et al.  Clasificación mediante técnicas no destructivas y evaluación de las propiedades mecánicas de la madera aserrada de coníferas de gran escuadría para uso estructural , 2011 .

[8]  J. R. Williams.  Non-destructive assessment of timber in historic buildings , 2009 .

[9]  Bo Kasal,et al.  Advances in in situ evaluation of timber structures , 2004 .

[10]  Ronald W. Anthony.  Examination of Connections and Deterioration in Timber Structures Using Digital Radioscopy , 2003 .

[11]  Wolfgang Rug,et al.  Strength of old timber , 1991 .

[12]  Paulo B. Lourenço,et al.  Chestnut wood in compression perpendicular to the grain : non-destructive correlations for test results in new and old wood , 2007 .

[13]  Jerzy Jasieńko,et al.  Selected Methods of Diagnosis of Historic Timber Structures – Principles and Possibilities of Assessment , 2013 .

[14]  Robert J. Ross,et al.  Nondestructive evaluation of wood , 1994 .

[15]  Paulo B. Lourenço,et al.  Guidelines for On-Site Assessment of Historic Timber Structures , 2015 .

[16]  Brian Ridout,et al.  Timber Decay in Buildings: The Conservation Approach to Treatment , 1999 .

[17]  M. O. Hunt,et al.  Stress wave timing nondestructive evaluation tools for inspecting historic structures: a guide for use and interpretation. , 2000 .