Long term creep tests on timber beams in heated and non-heated environments

The aim of this research investigation was to study the long term effect of creep on different wood materials under natural environmental conditions. The tests were initiated in the summer of 1992 and the results collected until the end of 1995 are reported here. The experiments on sawn timber of pine and spruce, glulam, Kerto-LVL and I-profile with hardboard web structural size members were carried out in a sheltered environment, where the changes in moisture and temperature of the surrounding followed the natural climatic conditions of Southern Finland. In addition, separate tests on eight glulam beams were carried out in a heated room environment. The experiments were carried out at low load levels (2...7 MPa). The surface of few groups of specimens were treated with alkyd and emulsion paint, some were creosoted and salt impregnated, while few samples had no treatment. The creep test data of all specimens were analysed systematically to obtain creep curves. The data showed significant variation in creep among wood materials with different treatments. Creep of glulam was same in heated and non-heated environment.