Eccentric Compression Performance of Parallel Bamboo Strand Lumber Columns

The influence of eccentricity ratio on the behaviour of 50 parallel bamboo strand lumber (PBSL) column specimens was studied under eccentric compression. The load-strain and load-deflection relationships were obtained from column tests, and the detailed failure modes for all specimens are reported. The eccentricity ratio is the main influencing factor on the bearing capacity of the columns, and the ultimate load values decreased with an increase of the eccentricity ratio. Both the ultimate middle deflection values and the absolute ultimate longitudinal strain values initially increased with the increase of the eccentricity ratio, and then stabilized or decreased slightly when the eccentricity ratio was bigger than approximately 0.8. The absolute ultimate lateral strain values for both face A (bracket side or compression side) and face C (tension side) performed similarly with the increasing of eccentricity ratios, increasing initially and then stabilizing or decreasing slowly. An equation for calculating the eccentricity influencing coefficient of PBSL columns is proposed. The calculation results obtained from the equations agreed well with the test results.