Improving the behavior of pile to sleeve connections by fiber reinforced cement based composite materials

In recent decades, the pile-to-sleeve grouted connections has gained significant popularity.Studies have shown that the failure mode of concrete in this connection is shear failure.Considering the failure modes of the connection, it is predicted that improving the performance of the concrete will also enhance the ultimate strength and ductility of the connection.In this research, the performance of the concrete was improved using steel fibers.For this purpose, 1.5% of straight steel fibers have been used in concrete to improve flexural strength and compressive strength.The results demonstrated that the use of 1.5% steel fibers improved the ultimate strength of the connection by up to 22% and also enhanced its ductility.Furthermore, the experimental results were compared with the DNV, API, and HSE standards, with the DNV standard showing the highest consistency with the experimental results.