Monitoring of bending stiffness of BFRP reinforced concrete beams using piezoceramic transducer enabled active sensing

Abstract

Corrosion of steel bars leads to significant structural deteriorations in reinforced concrete structures, increasing their maintenance costs and shortening their service life. Fiber Reinforced Polymer (FRP) bars, as an internal reinforcing material instead of steel bars, are used in concrete structures owing to its high tensile strength and corrosion resistance. However, the structures of FRP reinforced concrete bending components have the large deflection and the lower post-cracking bending stiffness. In addition, it is difficult to evaluate the bending stiffness of in service FRP reinforced concrete beam by using the traditional monitoring method. This paper proposes a novel approach to real-time monitoring of the bending stiffness of FRP reinforced concrete beams using piezoceramic transducers enabled stress wave propagation. In this approach, several piezoceramic smart aggregate (SA) transducers are bonded on the side-surface of a concrete beam reinforced with Basalt-FRP (BFRP) bars to evaluate the bending stiffness based on stress wave propagation. A piezoceramic SA transducers based bending stiffness index (Piezo-BSI) is proposed to quantify the bending stiffness levels of BFRP reinforced concrete beams. The results show that the bending stiffness of BFRP reinforced concrete beams can be effectively evaluated by using SA transducers. The proposed Piezo-BSI values agree well with the actual bending stiffness index. This indicates that the Piezo-BSI values can accurately quantify and effectively reflect the actual bending stiffness levels of concrete beams reinforced with BFRP bars.