Quasi-Full-Scale Experimental Study on Bridge Precast Concrete Columns under Static Loading

Abstract

Precast concrete columns have been widely used in bridge constructions. Most studies regarding precast columns focused on seismic instead of static behaviors. To investigate the cracking mechanism and failure modes of the columns with column-to-footing connections using grouted splice sleeves, four full-scale sliced specimens, two precast columns with different axial loads, and two monolithic columns with different cover thicknesses were designed and constructed based on their prototypes. These specimens were subjected to monotonic loading for failure. Experimental results showed significant differences between the precast and monolithic columns. The first crack of the precast column appeared in the joint section. The cracking load of the precast column was 10% less than that of the monolithic column. Nevertheless, the tensile strains of longitudinal bars in the precast column were approximately three times as large as that in the monolithic column. Strain and deformation concentrations occurred near the joint section. When the peak load was attained, the joint section became the failure section, and the lateral load was primarily balanced by the shear stresses in uncracked concrete. Based on the cracking mechanism and failure mode obtained from experiments, practical methods were proposed to calculate the cracking moment and bearing capacity of the joint section in precast columns and the difference between the calculated and measured results was less than 2% and 7%, respectively.