The increasing use of wood in civil engineering is closely connected to the development and spread of glued timber products. In Central Europe finger jointed structural timber gains increasing market shares, especially for substitution of ordinary sawn timber in trusses and timber frames.Particularly in the case of finger jointed structural timber the integrity of glued end-joints can be decisive for the safety of complete buildings, as there is no or only very little redundancy within this type of structural members.The production of finger-jointed -structural timber is subject to extensive quality regulations according to respective national and international production standards. The regulations comprise i. a. the control of production parameters such as the gluing pressure, temperature and moisture content and a factory production control by means of destructive testing of a small number of samples drawn randomly at regular intervals.Whereas systematic production errors (e.g. the increasing wear of cutters, gluing at unfavourable high moisture contents, etc.) can be recognised and avoided in general in a sufficient manner, the detection of sporadic errors, such as single defective cutting of adherents or individual lack of adhesive application, is extremely improbable.Due to this shortcoming of the existing quality control methods, the occurrence of finger-joints with strength relevant defects is rarely, but consistently reported from internal registers of producers and from accidents. The objective of this paper is to report the results of a recently finished research project dealing with the development and implementation of an advanced quality control method for finger-joints with combined use of the proof-loading principle and non-destructive testing techniques.
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