Compression resistance of short members as the basis for structural grading of Guadua angustifolia

•The structural grading of Guadua culms subjected to compression were developed.•Linear mass is the best indicating predictor for capacity grading, while density is the best one for strength grading.•Structural grading classifies Guadua culm into several structural grade and reduces its variability. This study develops the structural grading of Guadua bamboo culms subjected to axial compression. Both strength and capacity grading methods are explored. Several candidates for Indicating Properties (IPs) were measured and calculated. The strongest coefficients of determinations for structural grading were related to densities [e.g., (conventional) density (ρ) and linear mass (q)]. Density (ρ) is best IP for strength grading if the culm section is taken as a hollow circle. Alternatively, linear density or linear mass (q) provides higher coefficients of determination when used for capacity grading. By using intervals of each indicating property (IP), several structural grades were developed. Each grade has its Grade Determining Properties (GDPs) include mean compressive strength (fc) or load carrying capacity (Fu), five percent exclusion limit (R0.05), and characteristic structural property (Rk). The latter could be used in structural design. As bamboo is a hygroscopic material, the IP should be adjusted into standardized moisture content (12% Mc). The moisture content effect on compressive strength and capacity should also be measured to increase the reliability of estimation if densities (ρ or q) are chosen as the IPs. Since external diameter can infer the linear mass (q) and is also significantly correlated with wall thickness (t), average external diameter (D) may also be used as the sole IP in capacity grading. Structural grading can reduce the variability of Guadua’s structural properties since it classifies the culm into several suitable grades.