Title: Aggregate Size on Punching Shear Behavior of Interior Slab-Column Connections

Author(s): Marnie B. Giduquio, Min-Yuan Cheng, and Shang-Wei Lin

Publication: Structural Journal

Volume: 120

Issue: 6

Appears on pages(s): 113-122

Keywords: aggregate size; flexural reinforcement; punching shear

DOI: 10.14359/51739091

Date: 11/1/2023

Abstract:
Coarse aggregate size has been considered as one of the critical parameters affecting the shear resistance of reinforced concrete elements. However, existing research discussing its effects on punching shear is limited. In this study, 12 large-scale interior slab-column subassemblages were tested to investigate the influence of coarse aggregate size on the punching shear behavior of interior slab-column connections subjected to monotonically increased concentric load. Three aggregate sizes were selected: one with a nominal maximum coarse aggregate size, dagg, of 3/16 in. (4.75 mm), another with dagg of 3/4 in. (19 mm), and the last with dagg of 1 in. (25 mm). The experimental evidence indicated that all specimens failed in punching shear. In general, the increase in dagg improved the punching shear response, with an increase in either the normalized maximum shear or the corresponding deformation, or both. The effects of the dagg were more consistent and apparent in specimens with slab tensile flexural reinforcement ratios of 0.80 and 1.28%, where both the normalized maximum shear and the corresponding deformation increased as the dagg increased. For the specimens with (low) slab tensile flexural reinforcement ratios of 0.40 and 0.53%, the increase in coarse aggregate size led to an increase in the normalized maximum shear and the corresponding deformation when the dagg was increased from 3/16 to 3/4 in. (4.75 to 19 mm) due to better bond strength. As the dagg was further increased from 3/4 to 1 in. (19 to 25.4 mm), the effects of the dagg on the normalized maximum shear and the corresponding deformation were not apparent in the specimens with slab tensile reinforcement ratios of 0.40 and 0.53%.