Determination of ultimate loads for compression members in timber constructions

The design of compression members in timber constructions has to consider the increasing stress due to the non-linear behaviour of the members. The determination of the ultimate load of compression members requires the consideration of non-linear geometric behaviour if the bending moments increase more than 10 % in relation to the linear theory. In the German timber design code, DIN 1052 [1], two methods of calculation are suggested. The second method uses geometric non - linear theory (theory second order) for calculation of the ultimate load. According to DIN 1052 the load carrying capacity can be determined without reducing stiffness parameters using the modification factor. The calculation methods for compression members according to DIN 1052 are compared and differences between them are discussed. A calculation with identical results for the ultimate loads using either the first or the second method is proposed.