Eccentric compression behavior of long poplar columns externally reinforced by BFRP

The column, which is the vertical main structural part of the building, bears the force transmitted from the upper beam and slab and is a crucial part of the structure. In this study, the columns with a rectangular section cut from poplar were reinforced by basalt fiber-reinforced polymer (BFRP) strips with four different reinforced configurations. The mechanical behaviors of the specimens were also investigated under different eccentricities. Experimental results are presented as follows: for the wooden columns under axial compression, the wooden column BFRP with one layer spaced apart, two layers spaced apart, one layer fully filled, and two layers fully reinforced demonstrated increased bearing capacities of 3.13%, 30.00%, 40.63%, and 65.00%, respectively; the longitudinal strain increased by 7.54%, 19.65%, 22.06%, and 30.69%, and the lateral strain decreased by 26.53%, 29.80%, 41.30%, and 66.64%, respectively. Meanwhile, for the wooden column subjected to eccentric compression, the bearing capacities of the aforementioned wooden column BFRP configurations increased by 8.70%, 19.56%, 23.91%, and 30.43%; the longitudinal strain of the wooden column increased by 25.41%, 35.20%, 39.52%, and 41.85%; and the transverse strain increased by 130.77%, 166.77%, 192.57%, and 230.86%. In addition, the finite element model was used to simulate the eccentric compression behavior of the specimen. However, the ultimate bearing capacity and deflection of the analyzed column were higher than the test value. This finding was due to the completely ideal state of poplar in Finite Element Analysis (FEA) modeling without the influence of some initial defects, such as knots. These values can roughly be used as a reference for experimental results for the repair and reinforcement of poplar structures in Xinjiang.