Experimental Study On Shear Performance Of Partially Prefabricated Steel Reinforced Concrete Columns

Partially Prefabricated Steel Reinforce Concrete Column(PPSRC column)is a two-stage construction to form a complete column structure.The hollow shell with steel and steel skeleton is prefabricated in the factory,and the inner core concrete is casted on the construction site.It has many advantages such as convenient construction of prefabricated structure and good stress on steel reinforced concrete structure,which makes the factory production level and the development of industrialization model has been further improved and promoted.The shear performance tests of 18 PPSRC columns subjected to horizontal axial force and lateral monotonic concentrated load were completed.At the same time,a self-balancing frame for applying axial load during test loading was designed.The main parameters of the test include axial compression ratio,shear span ratio,core cast-in-place concrete strength grade,and cross-sectional form(hollow,solid).The load-displacement curve,the bearing capacity change diagram,the material load-strain curve and the ductility coefficient were obtained by observing the experimental phenomena and the failure modes,and combining the experimental data.The test results show that the higher the axial compression ratio is,the higher the shear capacity is,and the above-mentioned limit is exceeded.The axial compression ratio has little effect,and even the shear bearing capacity is reduced.The larger the shear span ratio,the lower the shear bearing capacity.With the increase of shear span ratio,the effect of shear span ratio on shear capacity is not obvious;the greater the strength grade of core cast-in-situ concrete,the higher the shear capacity,but the increase is not large;Comparing thehollow section specimen with the solid section specimen,it was found that the hollow specimen also has good bearing capacity.The shear capacity of the PPSRC column was calculated using the formulas in the three combined structural regulations,the calculated results were safe and the utilization of the material was low.Based on this,through the discussion and analysis of the elements contributing to the shear participation,the improved calculation formula of the shear capacity is proposed,and the calculation results are close,but the dispersion is large.The truss-arch model of PPSRC column is proposed.The contribution of the truss section is discussed by the modified pressure field model.The arch model introduces the influence of axial force on shearing,and considering the shearing effect of the steel,the shear capacity of the PPSRC column is established.The calculation method is relatively close,but the calculation is complicated.Combining the experimental phenomena,analyzing the working mechanism and influencing factors of PPSRC column,using the experimental data,and proposing statistical regression analysis formula to accurately calculate the shear capacity of PPSRC column,and compare and analyze with all calculation methods used,Statistical formula calculation results are in good agreement,small in dispersion,simple in calculation process,and recommended for engineering design.