Experimental and theoretical investigation of prefabricated timber-concrete composite beams with and without prestress

Abstract

This paper presents a summary of the experimental programmes and theoretical analysis of the bending performance of non-prestressed and prestressed timber-concrete composite (TCC) beams. Two non-prestressed and three prestressed composite beams were selected, and their flexural behaviour was evaluated. Three types of ductile fabricated connections were applied to the prestressed composite beams, whereas two types were applied to the non-prestressed beams. The concrete slabs with embedded steel plates and timber beams were connected together using coach screws. On the surfaces of the embedded steel plates, the portions in contact with the wooden beam were interspaced with a vulcanized rubber layer to improve the mechanical performance of shear connections and composite beams. A series of four-point bending experiments were performed until collapse failure occurred in a simply-supported scheme. The test results demonstrated that the TCC beams using steel plate + screw connections exhibited excellent structural performance. The flexural capacity of the prestressed specimens was improved by approximately 110% compared with the non-prestressed specimens. Due to the addition of the rubber layer in the TCC connections, the flexural capacity of the prestressed composite beams was improved by 25.2%. Based on the ‘γ–method’, a theoretical analysis was proposed for calculating the flexural capacity and bending stiffness for both non-prestressed and prestressed TCC beams. The theoretical results showed good agreement with the experimental evidence.