Experimental Research On Eccentric Compression Of High-strength Concrete Confined With High-strength Stirrup

Concrete columns confined with high strength spiral hoops have strong bearing capacity,good deformation capacity and excellent seismic capacity.The spiral stirrup can be directly prefabricated in the factory and bound after transporting to the building site,which greatly improves the construction efficiency.Given spiral stirrups is generally not considered in traditional design of bias component bearing capacity,and high strength compound spiral hoop reinforced column under eccentric loading conditions the mechanical performance study is relatively lack,therefore,this paper mainly studies the constraint column in the force performance of bias load conditions,and to explore the compound spiral stirrups in the constraint effect of specimen under eccentric compression.In this paper,eight high strength composite spiral stirrup reinforced concrete short columns are tested eccentric compression.The influence of initial eccentricity,concrete strength and the stirrup strength on the mechanical behavior of high strength composite spiral stirrup reinforced concrete short columns and constraint mechanism of the spiral stirrups are analyzed.The characteristics of eccentric compression failure are observed and summarized and the strains of stirrup and concrete data are recorded in order to facilitate subsequent analysis.In addition,the operation process of establishing an equal-size numerical model of the test component by ABAQUS software is introduced in detail.The parameters set in the experiment are used to design and load 8 reinforced concrete columns with high-strength spiral stirrups under eccentric compression,for further investigating the working performance of the specimens.Experimental phenomena and simulation results show that:(1).This kind of short column has good bias mechanical properties.The restraint efficiency of composite spiral stirrup increases with the decrease of initial eccentricity,decreases with the increase of concrete strength,and increases with the increase of stirrup strength.(2).The restraint of high-strength spiral stirrups to core concrete starts to play a significant role in the middle and late stages of loading,which is also the main reason that experimental models' bearing capacity and ductility are greatly improved.(3).The ultimate state of the eccentric compression bearing capacity of the high-strength composite spiral stirrup confined column is controlled by a large amount of spalling of concrete cover.when the experimental model reaches its ultimate bearing capacity,the "compound constraint" effect of the composite helical stirrup on the compression side is sound,and it still contributes to the bearing capacity of the bias column in the descending section.(4).The short column with high strength and helical stirrup restraint is divided into the core compression zone and the common compression zone,the eccentric compression is divided into four conditions and the corresponding compression bearing capacity formula is derived.The calculation results are in good agreement with the test results.