Flexural behavior of precast concrete beams in-span assembled with bolt-steel plate joints

Abstract

The assembly of precast concrete structural components is primarily concentrated at the splicing joints of the components. Wet connections involving additional stirrups and detailing cause casting difficulties and possibly deficient joints. Herein, a new type of precast beam in-span assembled with bolt–steel plate joints (PBSPB) is proposed. A significant unique feature is the discontinuous longitudinal reinforcement in the midspan, where the U-shaped steel plate covers the web and tensile zone of the concrete beam. The steel plates and bolts are used to connect the two assembled short beams to resist both flexure and shear owing to the external effects. To investigate the effects of the steel-plate thickness and span–depth ratio on the flexural behavior of beams, a static behavior test was conducted on six PBSPBs and one cast-in-situ beam. The failure mechanisms of the PBSPBs and cast-in-situ beam were examined and compared with regard to the crack propagation, load–displacement characteristics, and strain responses. All the PBSPBs exhibited excellent performance with limited cracks under identical conditions; only minor damage was observed, which consisted of small amounts of concrete spalling and edge warping of the steel plates. Finite-element analysis (ABAQUS) models of the proposed PBSPBs were developed to verify the ultimate load and damage situations of each specimen, a simplified flexural-capacity calculation formula for the PBSPB was developed, and the theoretical results were consistent with the experimental results. The results indicated that the new precast concrete beams had favorable flexural capacities. The beam with thicker steel plates in the span had a higher strength owing to the higher stiffness. Increasing the span–depth ratio increased the ultimate load and barely affected the failure mechanism.