Experimental Research On Bearing Performance Of Marine Concrete Pier Column Under Wave Loading

The bridge piers in the marine environment not only bear the erosion of various harmful ions,but also suffer from the impact of waves,which will cause damage to the pier columns and reduce their bearing capacity.The serious damage to the pier and pillar will lead to the collapse of the bridge,which will not only harm the personal safety,but also cause huge economic losses.Therefore,it is of far-reaching significance to study the bearing performance of marine concrete pier and pillar under the action of waves.Supported by the National Natural Science Fund project "Dynamic damage test research of marine concrete structures under wave action".The main contents are as follows:(1)The wave motion was described by the small amplitude wave theory,and the Morrison equation was used to calculate the wave load.Under the condition that the depth of water was far greater than the wavelength,the rationality of transforming the wave load into fatigue load was explained by analyzing the calculation results of wave load.(2)The continuous loading test,dry-wet cycle test,fatigue loading test and axial compression test of the pier column were carried out,and the change rules of concrete residual strain,reinforcement residual strain and the wave impact times-deflection in the fatigue loading test were analyzed,and researching the horizontal and longitudinal strains of concrete,Poisson's ratio and bearing capacity in the axial compression test.The results show that the residual strain values of steel bars and concrete conform to the three-stage change law,and the corrosion rate of steel bars significantly affect the residual strain values of steel bars and concrete.When the fatigue loading is finished,the residual strain values of steel and concrete are in the second stage,so the number of fatigue loading has little effect on the residual strain values of steel and concrete.The deflection values of pier increase with the increase of corrosion rate and loading times,and the influence of corrosion rate is more obvious;the longitudinal strain of concrete is generally larger than the transverse strain,and the horizontal strain increases slowly;the corrosion of reinforcement and fatigue loading will reduce the axial compression bearing capacity of pier.(3)Considering the influence of fatigue on the strength of concrete,the influence of fatigue and corrosion on the cross-sectional area of steel bars,and the influence of fatigue and corrosion on the yield of steel bars,based on the bearing capacity calculation formula in the code,the calculation formula of the axial compressive bearing capacity of marine concrete under the action of waves was derived,and the error analysis between the calculation value and the test value of the bearing capacity was carried out.(4)Based on the selected finite element simulation software,the constitutive relationship of reinforcement and concrete was introduced and calculated,and the simulated value of the pier column bearing capacity was compared with the calculated value of the formula.The bearing capacity of the pier in No.69 berth of Lianyungang was estimated by using the bearing capacity calculation formula derived in this paper,and the protective measures and principles of reinforcement corrosion and the protective measures of pier column were summarized.