Behavior of CFRP-Strengthened Chamfered Laminated Bamboo Lumber under Eccentric Compression

Laminated bamboo lumber (LBL) is an engineered bamboo with consistent and reliable mechanical properties that can be utilized in structural applications. Experimental studies showed that LBL columns perform well under compression, but the addition of eccentricity could induce excessive tensile stress, which may cause premature failure to bamboo fibers. This paper investigates the use of Carbon Fiber-Reinforced Polymer (CFRP) to suppress cracking of LBL in the tensile zone of eccentrically loaded columns. The mechanical properties of CFRP strengthened chamfered LBL columns with four eccentricity values of 30, 60, 90, and 120 mm were tested. Obtained results were analyzed to propose two analytical models to predict the ultimate bearing capacity of LBL columns under the considered loading case. Test results showed that most of the specimens failed due to delamination at the contact surface between CFRP and bamboo, resulting in fracture of CFRP at the midheight of the column. Consequently, mechanical connections in LBL also failed, and columns suffered a complete failure. Strain distributions within the column cross section showed linear variation showing compatibility with elastic bending theory. LBL columns strengthened using CFRP showed higher resistance under eccentric loading when compared against typical LBL columns; as the eccentricity was increased from 30 mm to 120 mm in 30 mm intervals, the ultimate load increased by 10.9%, 6.3%, 13.7%, and 17.9%, respectively. The results predicted using the two proposed models showed good agreement with test results.