Experimental Study And Theory Analysis On Limit Value Of Axial Compression For SRHSHPC Columns

The investigation of damage caused by earthquakes shows whether building collapse depends on the performance of columns in great part. Especially with the development of high-rise and long-span building, columns have to bear higher and higher axial load. To meet this need, the columns not only require high bearing capacity, but high ductility. Owing to high bearing capacity, excellent integral stiffness and seismic behavoirs, as a new structure, Steel reinforcement concrete (SRC) composite structure is developed rapidly in recent years. High strength and high performance concrete (HSHPC) has high strength, high working performance and excellent durability. Steel reinforced high strength and high performance concrete (SRHSHPC) structures that steel is encased by HSHPC make full use of advantages of steel and HSHPC and avoid their disadvantages, respectively.In this paper, failure pattern, hysteretic curves, skeleton curves, energy dissipation capacity, ductile coefficients, law of strength and stiffness degeneration of SRHSHPC frame columns are obtained through experimental results of 10 specimens which are tested under low cyclic repeated loading. The influence of shear span ratio, concrete strength and axial compression ratio on seismic behaviors of SRHSHPC frame columns is analyzed.Steel and concrete can cooperate well on the basis of the perfect bond effect between of them, The bond-slip behavior directly affects the failure patterns and performance of SRHSHPC columns, The value of slip along the height of columns is derived through theoretical analysis.Comparing with former test which more consider common concrete in SRC structures, the high strength concrete reached 125.38 MPa is used in this paper. Based on the test results, the limit value of axial compression ratio for SRHSHPC columns with different shear span ratio, whi0ch satisfies a given requirement of ductility, are obtained. According to equilibrium condition of stress, interfacial bond-slip behavior is considered, and the limit value of axial compression ratio for SRHSHPC columns made by different concrete strength is obtained through 4 flexural failure columns. The limit value of axial compression ratio recommended in the paper is verified by theoretical analysis.The research results show that SRHSHPC columns has excellent seismic behavior, as well as the brittleness of high strength concrete is improved because of the restraint effect of steel. The appropriate limit value of axial compression ratio is obtained under a given requirement of ductility, and it can be expected to guide the design of SRHSHPC structures.