Study for improvements in design codes of timber structures regarding developments in time

Abstract

Lilita Ozola, born 1950, received her Doctor degree in engineering from the Estonia University of Agriculture in 2005. Aivars BROKANS Doctoral Student Latvia University of Agriculture Jelgava, LATVIA coldzero@inbox.lv Aivars Brokans, born 1985, received his diploma engineer (2009) and Master degree in civil engineering from the Latvia University of Agriculture in 2011. SummaryThis paper presents the results on experimental research of the bending creep behaviour of softwood timber beams in uncontrolled microclimate conditions (unheated building, winter climate in the region near the Baltic Sea) under different levels of a constant load not exceeding the proportional limit. Experimental evidence is produced to corroborate the Eurocode 5 conditions for predictions of creep effects under variable load. Deflection values of beams in four point bending are measured daily during 3 months simultaneously performing monitoring of the moisture content of the wood, relative humidity and air temperature. It has been observed that at the initial period the character of creep development differs significantly comparing it with later period till the end of the test. The linear equations are found as sufficiently good approximations for relationship creep versus time at the moderate load levels not exceeding the proportional limit.

Development of mathematical model proposed for prediction of final deformation in bending of timber beams

“…Natural environmental conditions involve some additional uncertainty due to the unforeseen mixing of affecting factors however in a limited range [10], [11], [12]. Natural environmental conditions involve some additional uncertainty due to the unforeseen mixing of affecting factors however in a limited range [10], [11], [12].…”