**5. Conclusions**

This study sets out to improve the PCSAM with the SSAWC and the LCSS. Initially, the strengthening effects of the above two improvement measures on the bearing capacity of the strengthened specimens were verified using an axial compression test. Then, the extended parameter analyses were performed by establishing the numerical models. Finally, the calculation formula for the axial compression bearing capacity of the strengthened specimens was established. The following conclusions were made:


In addition, preparing the specimens requires a large number of steel molds and careful concrete curing, which takes a lot of time. Considering the time needed and the restrictions on research and development funds, only a small number of specimens were tested and a numerical simulation was conducted. As a consequence, the above-mentioned conclusions and remarks are only validated by limited experimental and simulation results. More experimental data and numerical simulations are needed to validate the proposed formulas in the future.

**Author Contributions:** Conceptualization, S.J. and S.W.; methodology, S.J. and S.W.; software, S.W. and H.Z.; validation, S.W. and Y.G.; formal analysis, S.W.; investigation, S.W.; resources, S.W. and S.J.; data curation, S.W. and H.Z.; writing—original draft preparation, S.W. and Y.G.; writing—review and editing, S.J. and S.S.; visualization, S.W.; supervision, S.S.; project administration, S.J.; funding acquisition, S.J. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was funded by the National 13th Five-Year Research Program of China (Grant No. 2016YFC0700706), Traffic Science and Technology Project of Fujian Communication Department, China (Grant No. 201536).

**Acknowledgments:** Heng Zhang assisted with the experiments. The authors also express their gratitude to the anonymous reviewers for their constructive comments and suggestions.

**Conflicts of Interest:** The authors declare no conflict of interest.
