Title:
Tests on Lightweight Concrete Deep Beams
Author(s):
Keun-Hyeok Yang
Publication:
Structural Journal
Volume:
107
Issue:
6
Appears on pages(s):
663-670
Keywords:
deep beams; lightweight concrete; shear strength; size effect; strut-and-tie model
DOI:
10.14359/51664014
Date:
11/1/2010
Abstract:
Sixteen deep beam specimens, some made of sand-lightweight concrete (SLWC) and others made of all-lightweight concrete (ALWC), were tested and compared with normalweight concrete (NWC) deep beams. The shear span-to-overall depth ratios investigated were 0.5 and 1.0, and the section overall depth varied between 400 mm and 1000 mm (15.7 and 39.4 in.). Test results showed that the size effect in lightweight concrete (LWC) deep beams was more significant than in NWC deep beams, and the effect of section overall depth on the ultimate shear stress was slightly greater in ALWC deep beams than in SLWC deep beams. The conservatism of strut-and-tie models (STMs) proposed by ACI 318-08, CSA, EC2, and Tan and Cheng is established against the variation of section overall depth in LWC and NWC deep beams without shear reinforcement. The ratio between predicted and measured shear strengths for LWC deep beams is higher than the ratio for NWC deep beams in all four STMs. Tan and Cheng’s model more closely agrees with the test results for NWC deep beams, while it overestimates the shear strength of LWC deep beams, showing that the overestimation slightly increased as the section overall depth increased.