Flexural Behavior of Laced Reinforced Concrete Moderately Deep Beams

Abstract

This paper aims to experimentally and numerically investigate the flexural behavior of laced reinforced concrete moderately deep beams. The study focuses on the influence of the lacing angle (30, 45, and 60°) and the ratio of the tension reinforcement (0.33, 1.13, and 2.01%). Six beams were fabricated, with a cross-sectional width of 150 mm and a depth of 240 mm, and 1530 mm in length. In five specimens, lacings were employed as shear reinforcement instead of the conventional stirrups. A reference beam was fabricated with conventional vertical stirrups. All beam specimens were subjected to the four-point bending up to failure with effective and shear spans of 1400 and 400 mm, respectively. Compared to the reference beam, laced beams experienced significant stiffness enhancements of up to 43.7%. However, the improvement in the ultimate load did not exceed 10%. The recorded strains in lacings clearly signify the efficiency of lacings in resisting the longitudinal and diagonal tension stresses induced along the flexural and shear spans. Moreover, a nonlinear finite element analysis was performed using ABAQUS, based on which parametric studies were conducted. Parametric studies showed that the ductility was significantly increased with the increase of lacings bar diameter, while the ultimate load capacity was only slightly enhanced.

Keywords

• deep beam
• lacing
• crack pattern
• ABAQUS
• concrete damage plasticity