| In recent years,large-scale marine constructions are underway in China for the purpose of developing oceanic economy and protecting maritime rights.However,traditional engineering structures located in marine environment,including the reinforced concrete structure,are seriously threatened by the problem of steel corrosion,which can significantly shorten structures' service life.In addition to that,the marine constructions are faced with the problem of long-distance transportation,which can lead to huge economic costs and construction delay.To solve the above problems,the present paper proposed a new column named as pultruded FRP profile-reinforced seawater coral aggregate concrete filled FRP tube(PPR-SCFFT for short).This hybrid column is composed of FRP tube,FRP profile and seawater coral aggregate concrete.wherein the coarse and fine aggregates of coral aggregate concrete is made of locally available coral.This column can completely solve the problem of corrosion and save transportation costs.In marine environment,the hybrid column may be subjected to periodic load including wave load.wind load,and earthquake load.Therefore.reversed cyclic loading tests were conducted to investigate the seismic performance of the hybrid column.In total,six PPR-CFFT specimens were fabricated and variables included the axial compression ratio,the fiber orientation,the thickness of FRP tube and the number of FRP profiles.As a comparison,three additional GFRP rod-reinforced concrete filled FRP tubes and one steel bar-reinforced concrete tilled FRP tubes were manufactured.By conducting pseudo static tests,the influence of various parameters on the failure mode,the ultimate loading capacity,the energy dissipation and ductility of the hybrid columns are discussed in detail.The experimental findings include:(1)The failures of all the columns were flexure dominant,which were characterized by the fracture of yield of inner reinforcement accompanied by the local crush of concrete;(2)The difference in inner reinforcement resulted in different load-displacement hysteresis curves.Apart from the steel bar-reinforced columns,the hysteresis curves of all other columns exhibited pinched shape;(3)For PPR-CFFT specimens,reducing the winding angle or increasing the thickness of FRP tubes improved the loading capacity and energy dissipation,but resulted in reduced ductility coefficient.In tension,the profiles were the primary resistance components,while in the compression,the profiles and the FRP tubes both contributed to the load resistance;(4)With the same reinforcement ratio,the loading capacity was hardly affected by the type of inner reinforcement,however,the ductility coefficient and energy dissipation varied greatly;(5)The hoop strain of FRP tube was linearly distributed along the height.The hoop strain had the largest value at the bottom of the column,indicating that the bottom concrete was well confined.In this paper,the strip method is used to analyze the most unfavorable section of the composite specimens of the composite aggregates and the composite specimens of coral aggregates.The bending moment of the column roots is predicted at the peak load,and the corresponding procedures are prepared by using MATLAB.The prediction results and experiments are carried out.similar.Finally,based on the experimental analysis and the relevant domestic specifications,the corresponding design method is given.The test results verify that the design method is safe and reliable,which can ensure the safety of the components and meet the needs of engineering design. |
PDF Full Text Request