Compressive behavior of square steel tube confined lightweight concrete with bamboo scrimber

Abstract

Bamboo scrimber, with its lightweight and high-strength properties, has emerged as one of the most promising green building materials. This study integrates bamboo scrimber into Steel Tube Confined Lightweight Aggregate Concrete (STCLAC) to form Square Steel Tube Confined Lightweight Aggregate Concrete Columns with Bamboo Scrimber (BSTCLAC), reducing structural deadweight and concrete usage. To comprehensively investigate the factors influencing the axial compression performance of these columns, key parameters were selected, including bamboo scrimber cross-section size, concrete strength, steel tube thickness, and the steel tube confinement type. A total of 15 specimens were fabricated and subjected to axial static load tests. The damage modes, displacement-load curves, load-strain curves, bearing capacity, and ductility were systematically analyzed. The test results revealed that under axial compression, the specimens primarily failed due to crushing at the structural joints of the steel tube. Bearing capacity increased initially but decreased as the cross-section size of the bamboo scrimber increased, with a maximum increase of 19.99 %. The increase in concrete strength led to a significant enhancement in bearing capacity, with a maximum increase of 37.01 %. Additionally, all BSTCLACs exhibited excellent ductility, with a maximum residual load capacity retention of 97.97 %. The inclusion of bamboo scrimber significantly boosted energy absorption and load-bearing performance under large deformations. Based on experimental data and unified strength theory, an axial compressive load capacity calculation model was proposed, demonstrating high accuracy with results closely matching experimental observations.