海 洋 环 境 下 腐 蚀 后 钢 管 桩 材 料 性 能 退 化 研 究

As important components of steel trestles,steel pipe piles are under serious corrosion threats in marine environments. This study examined the material properties and characteristics of steel pipe piles from a steel trestle bridge in the East China Sea,following five years of exposure to natural marine corrosion. A total of 16 tensile specimens were extracted from the splash zone,tidal zone and immersed zone of the steel pipe piles to analyze the degradation mechanical properties of each zone. Based on the experimental data,regression equations were established to relate elastic modulus,yield strength, strain hardening index,and strength coefficient to the average thickness residual rate. The fitting formulas for the true stress-strain curves of three regions were established based on the trilinear constitutive model. The results indicate that the splash zone experiences the most severe corrosion,and there are certain losses in the steel mechanical properties of each region. The regression equation can predict the yield strength of the three regions quite effectively. By comparing the applicable range of the average thickness residual rate in each region,it can be observed that the trilinear constitutive fitting formula is suitable for predicting steel pipe piles with more severe corrosion.