Experimental Study on Mechanical Properties of Precast Concrete Columns with Different Opening Ratios

To investigate the mechanical behavior of precast columns with openings in the beam–column joint core area under axial loads, a systematic study was conducted to examine the effects of the opening parameters on the axial mechanical performance of precast columns. Two sets of six precast concrete column specimens, with opening ratios of 14% and 22%, respectively, were designed and subjected to axial compression tests. The failure patterns, opening ratios in the core area, and other relevant parameters of the specimens were thoroughly analyzed. Additionally, a finite element model incorporating material non-linearities was developed using ABAQUS (2022) software, and parametric numerical simulations were conducted to further explore the structural response. The results indicated that the variations in the opening ratio had no significant effect on the cracking load of the specimens. However, as the opening ratio increased, the peak load of the compressed columns increased by 8.6%, and the ductility factor increased by 12.9%. The study also reveals that opening ratios below 30%, the casing thickness, and the bolt preload have minimal impact on the bearing capacity of precast columns. These findings provide theoretical support for optimizing hole sizes in dry bolted connections for precast concrete structures.