Interaction Between Steel And Concrete In Solid Web Steel Reinforced Concrete Column

At present, limited researches have been conducted on composite interaction between steel and concrete, influence of shear connectors on failure mode and bearing capacity, and design method of shear connectors in steel reinforced concrete (SRC) columns. In this paper, based on tests of 20 specimens, a study on composite interaction between steel and concrete in solid web SRC columns is carried out by means of theoretical and numerical analysis methods.Tests on 18 SRC specimens with and without shear studs and 2 RC specimens were carried out under low cyclic loading. The cubic strength of concrete was in the range of 74.4MPa to 80.4MPa. The failure process, failure mode, rigidity, and bearing capacity were investigated and compared. Seismic performances including energy dissipation, ductility, and ultimate deformation capacity were researched. The influences of shear studs, width of steel flange, height of steel, and stirrup ratio on the seismic performance of SRC column were analyzed. Based on the experimental study, the influences of shear studs on failure process and failure mode, energy dissipation, ultimate deformation capacity and ductility, rigidity and bearing capacity were clarified.Slip sensors developed by the author were used for measuring the slip between steel and concrete in the specimens by having installed before concrete pouring. Strain gauges were placed at top and bottom of the shear stud. The laws of slip and the strain of shear studs were analyzed. Model shapes were proposed to reflect the relationship of slip v.s. loading force, slip v.s.stud strain, and stud strain v.s. loading force. It was revealed that the slip of shear failure specimen at the beginning of loading was similar to that of bending failure specimen.The axial force distribution mechanism of SRC column under bending was studied. The source of slip was explained from the macro view of axial force distribution and the micro view of strain distribution, respectively. Slip mechanism under bending was put forward in this paper, and quantitative calculation method and formula for slip were presented.On the basis of quantitative calculation of slip, the calculation method of bearing capacity for SRC column with or without shear connectors under compression bending was presented. After analyzing numerical examples, recommendations for design of shear connectors were given.A new method, proposed by the author for calculating shear bond failure capacities, was compared with test results, which showed that the new method was more accurate than Japanese code in terms of estimation of shear bond failure and corresponding capacity. In addition, the new method can calculate compression shearing capacity of SRC column with or without shear connectors.Based on previous hypotheses for behavior of shear failure of uncracked reinforced concrete by Alan H. Mattock and Neil M. Hawkins, membrane-element theory and strut-tie theory were used to explain the shear failure mechanism, and the previous hypotheses were refined and further developed. Simple formula for calculation of shear failure capacity was presented in this paper. Using test results of 36 initially uncracked reinforced concrete specimens with normal and high-strength concrete, shear failure capacities given by the new calculation method were evaluated. Results showed that the new calculation method was accurate and safe for estimation of shear failure capacity.According to experimental study and analysis of shear mechanism, recommendations for design of shear connectors in SRC columns under compression shearing were given.