Effect of inclination angle on the pull-out strength of bonded anchors installed in low-strength concrete

Abstract

Bonded anchors are commonly used in the strengthening of reinforced concrete structures to ensure effective bonding between the existing and new concrete. In chemical-anchor applications, the anchor direction is typically perpendicular to the concrete surface. Most approaches adopted to design chemical anchors assume that the anchor direction is the same as the direction normal to the concrete surface. However, owing to certain requirements or application errors, the anchor direction may differ from the direction normal to the concrete surface. In this study, the effect of the inclination angle on the anchor strength was experimentally investigated. In addition to the inclination angle, the anchor embedment depth and concrete strength were also considered. As the concrete strength is generally lower than the design strength of reinforced concrete buildings that need to be strengthened, low-strength concrete was considered in our analysis. During our analysis, pull-out tests were conducted on 30 samples for five different angles (0°, 10°, 20°, 30°, and 40°), three embedment depths (64, 96, and 128 mm), and two concrete grades. The results obtained from the experiments were analyzed and statistically evaluated. The analysis revealed that an inclination angle of up to 10° did not have a significant effect on the pull-out strength, and the decrease in strength for angles up to 30° could be compensated by an increase in the embedment depth. Moreover, some experiments showed that increasing the inclination angle can positively contribute to the energy absorption capacity of the joint.