On a number of occasions glued laminated timber breaks apart before the end of their service life. Examples in Germany (Frese M., Blaß H. J. [2011]) and Denmark (Hansson, Larsen [2005] ) show that this problem is real. In order to find the causes of the problem, extensive tests were conducted: 16 buildings with glued laminated timber were examined on the spot, calculations and laboratory work were carried out. These examinations told us that not only did the properties of the wooden material cause the damage, but the problems were also due to the wood used and the method of construction. In the calculations, the external load and residual stresses occurring in the glued laminated timber were included. Residual tensions in this timber were generated by climatic stresses and also due to the method of construction. These stresses also accumulated along with the stresses of the external load. Laboratory work was carried out to measure the delamination. We examined whether these analyses and calculations prove or disprove the results of the on- the- spot examinations.
Design, Fabrication and Operation Proposals for Glued-Laminated Timber, Based on Measuring and Modelling Results, Chapter 1: Literature Review and the Results of Examinations of the Spoil of the Glue Laminated Timber Beams
Glue laminated timber beams have been used in an increasing number of cases in the past 50 years. Glue laminated beams are durable constructs if they are manufactured from adequate quality materials and if their installation and operation are performed to a high quality standard. There are however an increasing number of cases of glue laminated beams suffering damage and as a result entire roof structures becoming life-threatening. Because of the arising problems the most important building complexes in Hungary-in which glue laminated beams are used as bearing structures- have been examined, considering both the demage problems of the existing structures and the operating features of the buildings. Later the reasons for the demages were examined with measurements and caculations. From all these observations conclusions and suggestions have been outlined both for the design, construction and operation.
Design, Fabrication and Operation Proposals for Glued-Laminated Timber, Based on Measuring and Modelling Results, Chapter 2: The Calculation Model and its Results Used for Determination the Reasons of Damaging of Glued -Laminated Timbers
Glue-laminated timber beams have been used in an increasing number of cases in the past 50 years. Glue-laminated beams are durable constructs if they are manufactured from adequate quality materials and if their installation and operation are performed to a high quality standard. There are however an increasing number of cases of glue-laminated beams suffering damage, and, as a result, entire roof structures becoming unsafe. Because of the arising problems the most important building complexes in Hungary, -in which glue-laminated beams are used as bearing structures,- have been examined. The assessment included both the damage problems of the existing structures and the operating features of the buildings. Later, the reasons for the damages were determined with measurements and caculations. From all of these observations, conclusions and suggestions were outlined for the design, construction and operation of the structures.
