IN SITU ASSESSMENT OF STRUCTURAL TIMBER ELEMENTS OF A HISTORIC BUILDING BY MOISTURE CONTENT ANALYSES AND ULTRASONIC VELOCITY TESTS

摘要

The Moisture content analyses (MC) and the ultrasonic velocity measurements (UVM) promise to be particularly important to assess the state of deterioration and the adequacy of the boundary and microclimatic conditions for timber elements when applied to a building with an important artistic and historical value. These nondestructive evaluation (NDE) methods supported by laboratory analyses of timber samples were applied in the inspection of a 16th century housing building, Corral del Conde in Seville, Spain. The methodology used was the non-destructive testing for determination of moisture content and measures from the times of transmission of ultrasonic waves to detect internal defaults. This methodology allows establishing the diagnosis of a wooden structure, obtaining an estimate of the degree of impairment of the same, and assessing the bearing capacity of timber elements for rehabilitation works. The combined interpretation of the results was done to assess the condition of structural timber elements in terms of their state of preservation, the dampness problems and the recent incompatible repairs affecting them. Results indicated that moist areas in the structure were associated with ground and roof drainage problems. Juxtaposition of the MC and UVM together with laboratory analyses was found to be useful to assess the different states of deterioration of timber, enhanced the accuracy and effectiveness of the survey and facilitated to build up the urgent and long-term conservation programs.