Failure Mechanism And Calculation Methods Studies On Eccentric Loaded Concrete Columns Reinforced With GFRP Bars

Due to steel prone to rust of the reinforced concrete member that led to the decrease of the bearing capacity of the whole structure,especially for some structures in island engineering or corrosive environment for a long time.Because of the effect of corrosive environment such as sea water that cause the safety performance of the whole structure big discount.In order to solve this problem,researchers put forward a completely effective method that using inorganic fiber reinforcement(FRP tendons)instead of steel to solve the problem of steel corrosion in concrete structures.Nowadays,a systematic research have completed at home and abroad include the tensile properties of FRP tendons,bonding between FRP tendons and concrete performance and flexural properties of FRP reinforced concrete beam.As for the study of compression performance in FRP reinforced concrete column is less,but the design method of FRP reinforced concrete column research is almost blank.Based on it,this article intends to carry out experimental research on the mechanical performance of FRP reinforced concrete column and the finite element analysis,and put forward the section as part of GFRP and concrete compression column tensile zone of concrete crack width limit as a design theory of limit state design method.The paper main research study includes the following aspects:Firstly,the axial compression and eccentric compression characteristics of concrete column reinforced with GFRP rebars are studies in the experiments of 5 axial compression columns and 12 eccentric compression columns,respectively.The influence of critical parameters including stirrup spacing,reinforcement ratio,concrete strength,eccentricity and slenderness ratio are focused in the experiments.The test results show that the failure modes of GFRP reinforced concrete columns are the concrete crushing destruction.The distribution of the strains on the mid-span crosssection basically satisfies the assumption of plane section.With the increase of concrete strength and GFRP reinforcement ratio of longitudinal reinforcement or the decrease of eccentricity,slenderness ratio and stirrup spacing,which improved the ultimate bearing capacity of specimen.Secondly,considering crack width limit is part of the cross section of the GFRP reinforcement concrete compression column edge compressive zone of concrete strain values.Using ABAQUS software to establish relevant part section made of GFRP and concrete compression column nonlinear finite element model,the test results and the programmed computed ones are in good agreement.On the basis of it,which discuss the effects of parameters such as the reinforcement ratio,eccentricity and slenderness ratio on the edge of concrete compressive strain.The results show that it have safety reserve to use the tension zone of the concrete crack width limit as part of GFRP reinforcement concrete cross-section compression column design limit state.Thirdly,based on the design code of reinforced concrete.According to the internal force equilibrium,deformation compatibility and second-order effect,calculation methods of ultimate bearing capacity of GFRP reinforced concrete eccentric compression column are presented with the consideration to two modes of part of the cross section of compression and compression of whole cross section respectively.There is only about 10% mean error between the calculation results and the test results.At the same time,comparison the difference between GFRP reinforced concrete compression of whole cross section column and reinforced concrete small eccentric compression column.