Local compression behavior of UHPFRC: Experiments and bearing capacity calculation model

Abstract

To evaluate the mechanical properties of the anchorage zone of prestressed UHPFRC structure, an experimental study was conducted on 54 UHPFRC specimens with central channels using local pressure tests. The local compression bearing capacity and load–displacement relationship were obtained. The experimental results indicated that there were four stages of local compression behavior in specimens: compaction, elastic deformation, crack development in the peripheral concrete and its interface with the wedge, and failure. The local compression cracking load of UHPFRC specimens was generally 40%-80% of the ultimate load. The local compression area ratio had a large effect on the vertical stiffness of UHPFRC local compression specimens. The increase in steel fiber length-diameter ratio (from 65 to 80) improved the transverse flexibility of the specimens. The average increases of UHPFRC local compression cracking load and ultimate load were up to 18.81% and 10.04% when the steel fiber volume content increases from 1% to 3%. The increase of the local compression area ratio on the local compression bearing capacity of UHPFRC ranged from 0.10% to 30.93%. Finally, the analytical formula was proposed to calculate the local compression bearing capacity of UHPFRC by fully considering the effect of the tensile strength of UHPFRC on the hooping action of peripheral concrete. This research provided a novel insight into the accurate bearing capacity calculation methods for UHPFRC in anchorage zones.