Numerical Analysis of the Crack Resistance of Post-tensioned Prestressed Concrete Anchorage Zone with Spiral Fe-SMA Stirrup

The tensile stress caused by the diffusion of the prestress in the post-tensioned anchorage zone will Induce premature cracks at the end anchorage zone of prestressed concrete structures. Indirect steel reinforcements are usually adopted to resist tensile stress. However, too dense indirect reinforcements often have an adverse effect on the casting quality of the concrete. In light of the above, it is proposed in this paper to replace the conventional steel spiral stirrup with the newly developed iron-based shape memory alloy (Fe-SMA) spiral stirrup, which can generate hoop confinement through its shape memory effect (SME). The extra hoop confinement provided by the Fe-SMA spiral stirrup could theoretically improve the cracking resistance of the anchorage zone. A finite element model using ABAQUS was established to simulate the compression performance of a concrete prism with the Fe-SMA spiral stirrup, and the model was verified by theoretical calculation results. The transverse stresses along the tendon path under different hoop prestressing levels in the elastic stage were compared. Moreover, the load-displacement curves and the cracking of the overall anchorage zone were also investigated. The results showed that using the Fe-SMA spiral stirrup can effectively improve the anti-crack performance of the anchorage zone.