Experimental Research On Oblique Shear Strength Of Rectangular Frame Column With Different Stirrup Areas On Two Principal Axis

Experimental results about shear strengths of rectangular reinforced concrete frame columns under oblique horizontal loads have been published by the domestic and overseas researchers in decades. It is indicated that the relationship of shear strength between X and Y axis of rectangular frame column with same or different stirrup area on two principal axis can approximately be described as a correlation equation of ellipse by analysing these results. The bilateral shear strength of rectangular frame column can also be calculated according to the correlation relationship of bilateral shear strength. However these researches on bilateral shear strength of rectangular frame column published before just concentrated on the correlation relationship and the calculation of bilateral shear strength. Stress performance and destructive mechanism of rectangular frame column subjected to oblique horizontal load are seldom investigated. Truss-arch model which can explain mechanics properties of rectangular frame column under oblique horizontal load is never established. So it is necessary to set up a mechanics model which force transmit path is clear and mechanism of destruction is correct through experiment results.Experiment to study bilateral shear strength of rectangular frame column had been carried out based on rectangular frame columns without stirrup and with different stirrup area on two principal axial. The results indicated that correlation relationship of bilateral shear strength of rectangular frame column without stirrup can be approximately described as ellipse, and which may be the essential reason that the correlation relationship of bilateral shear strength of rectangular frame column with different stirrup area on two principal axial can also be approximately described as ellipse.Based on the above conclusion, a reduced coefficient of bilateral shear strength of rectangular frame column without stirrup has been introduced to calculate bilateral shear strength of rectangular frame column, namely design method of depreciation coefficient. Simplified the correlation relationship of bilateral shear strength of rectangular frame column without stirrup to there straight line. Three-polygonal convenient method suited for the calculation of bilateral shear strength of rectangular frame column is also provided. It is shown that these two methods can calculate bilateral shear strength of rectangular frame column safety by comparing the results between calculation and experiment. Moreover, bilateral shear strength of rectangular frame column with different stirrup area on two principal axes has been calculated by formula offered by Code for design of concrete structures. It is shown that the results calculated by Code are safe.Based on unilateral truss-arch model and the analysis about correlation relationship of bilateral shear strength of rectangular frame column, a formula which can calculate bilateral shear strength of rectangular frame column safely is given out. At last, a spacial truss-arch model is established based on unilateral truss-arch model through analyzing destructive appearance and mechanism of rectangular frame column under oblique horizontal load. Mechanics property of rectangular frame columns under oblique horizontal load can be explained well by spacial truss-arch model. It is shown that the spacial truss-arch model considering much elements effecting bilateral shear strength is feasible and safe by comparing the results between experiment and calculation.