Study On Axial Compressive And Seismic Behavior Of Corroded Steel Pipe Piles Underwater Reinforced With Grouted FRP Jackets

Research of this paper is on the axial compression and seismic performance of steel tubular column with FRP Jakets reinforced.At present,in the construction of wharfs and offshore platforms,the use of steel pipe pile foundation is increasing gradually,while the research on seismic performance of steel pipe piles after corrosion is less at home and abroad,especially after the reinforcement of steel pipe corrosion.Therefore,in order to observe and compare the failure modes of corroded steel pipe piles under constant axial compression and seismic test,the effects of different corrosion rates and reinforcement on the axial compression and seismic performance of corroded steel pipe piles are studied.The main works and achievements are as follows:(1)Three groups of eight specimens(three specimens with corrosion rate,three specimens with different grouting materials,one specimens with different Jakets diameters and one comparative specimens)under axial compression were tested and their failure modes were described,and their axial compression performance including bearing capacity,axial compression stiffness,peak load,peak strain and ductility coefficient were compared and analyzed.The effects of FRP Jakets diameter,corrosion rate and different internal grouting materials on the axial compression properties of specimens were studied.The experimental results show that with the linear increase of corrosion rate,the horizontal bearing capacity of the specimens decreases rapidly.After reinforcement,the bearing capacity,ductility and energy dissipation of the specimens can basically restore to the level of non-corrosion.However,too high corrosion rate will affect the effect of external reinforcement,and can not make the internal steel pipe and external Jakets and grouting material work well together.(2)the test process and final failure modes of two groups of 7 seismic specimens(3 corrosion specimens,3 reinforced specimens and 1 contrast specimens)are described,and their seismic performance including hysteretic curve,skeleton curve,stiffness degradation,energy dissipation capacity analysis,curvature analysis and ductility coefficient are compared and analyzed.F(3)This paper explores the finite element numerical simulation method,and uses OpenSEES software to simulate the seismic test.The main purpose of the simulation is to verify the test,and the verification effect basically coincides with the test.The software ABAQUS is used to verify and supplement the axial compression specimens,and the calculated curves are in good agreement with the experimental ones.Based on the validation model,the effects of steel yield strength,corrosion rate and other parameters on the axial compression performance of steel pipe piles are further studied.The results of the study can provide useful reference for the related research of rusted steel pipe piles.