Study On Axial Compression And Bias Performance Of CFRP Partially Wrapped Rectangular Steel Tube Short Columns

During the past several decades,concrete filled steel tube(CFST)members were widely used in practical engineering including high-rise building,large span bridge and heavy traffic highway,due to their outstanding advantages of high strength,good ductility,convenience construction,economic benefits and outstanding fire and seismic resistence.However,during the whole life of the construction,the issues in terms of the core concrete imperfection induced by the problem of concrete placement,the corrosion caused by the damp or acid condition and the weld avulsion resulted from the weld imperfection,would obviously dent the strength,ductility and durability of the CFST structures,and therefore serious engineering accident would be triggered.With the development of high-strength composite material technology,carbon fiber reinforced polymer(CFRP)was popularly used in strengthening engineering because of its advantages in light-weight,high-strength and easy construction.Related investigations indicated that using CFRP for the CFST members could obviously improve its strength,repair damage and supply the loss by providing lateral confinement.Till now,researches mainly focused on the fully CFRP-wrapped CFST members,whereas studies on the partially CFRP-wrapped CFRP members were seldom founded.This paper established an accurate and proper finite element(FE)modeling of CFRP partially-wrapped rectangular CFST stub column under axial and eccentric compression based on the.Detail work can be described as follows:(1)Based on some experiments on the CFRP partially-wrapped CFST stub columns subjected to axial load,a numerical modeling on CFRP partially-wrapped rectangular CFST stub column was established.A systematic parametric analysis on the axially-loaded CFRP partially-wrapped rectangular CFST stub column was conducted.Typical failure modes of the type of composite column were revealed.Moreover,the efficient wrapping approach of CFRP wrapped rectangular CFST stub column in a partial scheme was discussed.(2)Similarly,a proper FE modeling of CFRP partially-wrapped rectangular CFST stub column under eccentric compression was developed according to some relevant eccentric tests.Detail parametric analysis was developed,and the typical failure patterns of the column in eccentric compression condition were revealed.The effective strengthening management was analysis as well.(3)Based on the numerous FE results,the regression fitting work on the numerical data of CFRP partially-wrapped rectangular CFST stub column under axial and eccentric compression was conducted according to the unified theory and deeply mechanical analysis.Finally,design methods on the aforementioned loaded composite columns were proposed.The research would provide a basic reference for employing CFRP for the CFST structures.