Seismic performance of column using extrusion sleeve connection and precast reinforcement cage with XPS permanent templates

A new construction method is proposed to address the challenges associated with the construction of column-column joints in precast reinforced concrete (RC) frames. This methodology incorporates the use of expanded polystyrene (XPS) permanent insulation templates for pre-assembled reinforcement cages, coupled with extrusion sleeve splicing techniques. Low-cyclic loading tests were conducted on three column specimens fabricated using this method and one cast-in-place RC column specimen. The test results indicated that bending failure was the prevalent failure mode across all specimens. The column using the new construction method showed comparable bearing capacity and stiffness to the cast-in-place column, with a minor enhancement in energy dissipation capacity. The extrusion sleeve splicing demonstrated effective stress transfer capabilities as a Grade I splice, while the splice area percentage of 100 % within the bottom section of the column had a limited impact on the seismic performance. Unlike columns utilizing grouting sleeve splicing, the existence of XPS permanent templates and extrusion sleeve splicing did not alter the position of the plastic hinge. In addition, the study performed model validation and parametric analysis of the finite element model. Both experimental and numerical results indicated that an increase in the axial compression ratio and longitudinal reinforcement ratio significantly enhances lateral bearing capacity, stiffness, and energy dissipation. In contrast, the effect of increasing the volume stirrup ratio on lateral bearing capacity was found to be less pronounced. Finally, the proposed calculation method, which references the mechanical model of common RC columns, was deemed suitable for accurately determining the flexural capacity of the novel column specimens.