In situ assessment of the timber structure of an 18th century building in Madrid, Spain

Abstract The timber structural members of a seven-story building from the end of the 18th century were evaluated following a procedure based on previous research works. The structure consisted of timber-framed brick walls and heavy timber floors with mortar filling. Non-destructive measurements were taken in 13 sampling areas of the floors and framed walls. Detailed measurements of at least 3 pieces in each sample were taken (stress wave Time-of-Flight and probing tests). Mean density and modulus of elasticity values and characteristic values of bending and compression strength were estimated. On-site load tests were carried out on three floor slabs to deduce their actual bending stiffness and compare it with estimation by NDT. They behaved more rigidly than expected, which is explained by floor screed stiffness, the transverse stiffness effect and possible semi-rigid connection behaviour at the supports. Structural verification determined the required strength of the critical members to compare this with the estimated strengths, showing a correct safety level.