_Applied_  
_sciences_  
_Article_  
Corrosion Effects on the Mechanical Properties of Spun  
Pile Materials  
[PERSON] 1,* and [PERSON] 2(c)  
Department of Civil Infrastructure Engineering, Faculty of Vocational, Institut Teknologi Sepuluhn Nopember, Surabaya 60111, Indonesia Research Center for Urban Safety and Security, Kobe University, Kobe City 657-8501, Japan Correspondence: [EMAIL_ADDRESS]  
Footnote 1: email: {[[https://www.mdpi.com/journal/applsci](https://www.mdpi.com/journal/applsci)]([https://www.mdpi.com/journal/applsci](https://www.mdpi.com/journal/applsci))}  
Footnote 2: email: {[[https://www.mdpi.com/journals/applsci](https://www.mdpi.com/journals/applsci)]([https://www.mdpi.com/journals/applsci](https://www.mdpi.com/journals/applsci))}  
Footnote 3: email: {[[https://www.mdpi.com/journals/applsci](https://www.mdpi.com/journals/applsci)]([https://www.mdpi.com/journals/applsci](https://www.mdpi.com/journals/applsci))}  
Footnote 4: email: {[[https://www.mdpi.com/journals/applsci](https://www.mdpi.com/journals/applsci)]([https://www.mdpi.com/journals/applsci](https://www.mdpi.com/journals/applsci))}  
Footnote 5: email: {https  
Numerous studies have been conducted to investigate the damaging effects of corrosion on the mechanical properties of rebar, either by experiment or numerical simulation [8; 9; 10; 11; 12; 13]. The previous studies employed plain and deformed rebars with various diameters and yield strengths and indicated that the corrosion effect caused the reduction in the tensile strength and elasticity of the rebar. By creating cubic specimens of regular concrete with and without rebar, an experimental study was conducted to investigate the impacts of corrosion on the degradation of the compressive strength of concrete [14]. Other experimental studies [5; 15; 16] have investigated the corrosion effect on bond strength reduction by conducting pull-out tests on rectangular and cylindrical specimens of regular concrete. In all the studies mentioned above, corrosion effects on the mechanical properties of concrete, rebar, and bond strength have been investigated individually. There are few comprehensive studies of the impact of corrosion on the mechanical properties of reinforced concrete, especially for structural elements with circular hollow sections like spun piles. The corrosion attack may lead to early brittle failure of PSW foundations due to material deterioration over time, as shown by [PERSON] et al. [17] and [PERSON] et al. [18], who investigated the capacity of hexagonal and cylindrical corroded piles, respectively. It should be noted that those studies used mechanical properties of the pile material obtained from other studies carried out independently. Therefore, a comprehensive observation of the corrosion effect on the mechanical properties of spun pile materials is necessary to determine the performance of the corroded spun piles accurately. Changes in the mechanical properties of the material result in changes in the dynamical response of PSW. Several studies have investigated techniques to evaluate the dynamic response of structures [19; 20].  
This study aims to comprehensively evaluate the corrosion effect on the mechanical properties of spun pile materials using a three-dimensional (3D) finite element analysis (FEA). Throughout 0-75 years, the impacts of nonuniformly distributed rust on the rebar area loss, the concrete compressive strength, the yield strength of PC-bars, and the bond strength were all thoroughly examined. The 3D FEA results were reviewed to determine the stress-strain relationship of corroded spun pile materials and the bond-slip relationship between the corrosion-damaged PC-bar and concrete. Equations to predict the deterioration degree of the mechanical properties of corroded spun pile materials were proposed and compared to the equations presented in the previous studies.