RELATIONSHIP BETWEEN STATIC AND CYCLIC FRONT TO BACK LOAD CAPACITY OF WOODEN CHAIRS, AND EVALUATION OF THE STRENGTH VALUES ACCORDING TO ACCEPTABLE DESIGN VALUES

Abstract

Tests were carried out to investigate the relationship between static and cyclic strength of wooden chairs. Furthermore, cyclic front to back load performance of chairs were compared with acceptable design loads that were given in the American Library Association (ALA) specifications. For this purpose, 90 chair frames were constructed of Turkish beech (Fagus orientalis L.) with round edge mortise and tenon joints, with tenons that varied from 30, 40, and 50 mm in width and 30, 40, and 50 mm in length. All joints were assembled with 65% solid polyvinyl acetate adhesive. Half of the chairs were subjected to "cyclic" loads and the other half were subjected to "static" loads based on the ALA specifications. In conclusion, it was recommended that the cyclic strength could be taken as the 56% of the static strength. According to the results, the chairs constructed with any size of tenons could meet the light-duty service (domestic usage), except for the chairs constructed with 30 by 30 mm tenons. The chairs constructed with 50 by 50 mm tenons could meet the heavy-duty service, whereas the chairs constructed with 30 by 50 mm tenons could meet the medium-duty service.