| Compared with traditional reinforced concrete members,rectangular concrete-filled steel tubular members have many advantages such as good shear resistance,high bearing capacity and light weight.Today,usage is increasing in high-rise and long-span buildings.Studies have shown that short columns with small shear spans are prone to shear failure.At present,the fruitful results in the research on unidirectional shear resistance of rectangular concrete-filled steel tubular members have been reflected in the relevant specifications,but the research results in bi-directional shearing are still in the blank.Therefore,it is of great significance to study the double shear mechanical properties of rectangular concrete-filled steel tubular members and its application in engineering.(1)In the study of the shear mechanical properties of rectangular concrete-filled steel tubular members,the design of the rectangular concrete-filled steel tubular members must be subjected to bending and shear calculation.When the shear calculation result is greater than the horizontal force corresponding to the bend yield,it means that the rod is damaged by the shear,and vice versa.According to the actual engineering application and the shear failure of rectangular concrete-filled steel tubular members,the paper sets the square and rectangular concrete-filled steel concrete examples to a total of 9 sets(400mm × 400mm,400mm× 500mm-400mm × 1200mm),shear span ratio(0.25???1.5 change amplitude 0.25),loading angle(0°,15°,30°,45°,60°,75°,90°)as variables,combined with each other,a total of 378 examples.(2)Taking the square concrete-filled steel tubular members as an example,the current norm shear capacity formula is calculated.The results show that the technical specification of "rectangular steel tube concrete structure" CECS 159:2004,the result of"combination structure design specification" JGJ 138-2016 and "steel tube concrete The result of the structural technical specification-GB50936-2014 it is found that the calculation results of the shearing formulas of different specifications are different.(3)Through the summary of the results of the above 378 examples,the shear performance of rectangular concrete-filled steel tubular members is studied in depth.The results show that the shear capacity of square-section concrete-filled steel tubular members is independent of the horizontal load direction;when the loading direction is different,the shear capacity of rectangular concrete-filled steel tubular members is different;when the aspect ratio is larger,the shear bearing capacity is different.The result is more different.The finite element of shear force-displacement,shear-shear span ratio curve and the current shearing formula are discussed with the shear span ratio,aspect ratio and loading angle as the main parameters.The effects of shear span ratio,aspect ratio and loading angle on the shear capacity of rectangular concrete-filled steel tubular members are analyzed.The calculation method of one-way shear practicality is fitted,and the calculation results of the fitting formula are compared with the finite element results.Good agreement.According to the two-way anti-shearing idea of reinforced concrete columns in the concrete structure design specification gb 50010-2010,the two-way shear correlation of rectangular concrete-filled steel tubular members is studied.The results show that the equation of the biaxial shear capacity of rectangular concrete-filled steel tubular members approximates the elliptic equation(?)(4)Taking an actual engineering structure as a review case,the structure span is about 24mx40m and the load is large.The tie rods in the structure are typically small shear span members and are bi-directional shearing.The research results of this paper verify the safety of the structural design of the project.At the same time,it proves that the calculation formula of the shear strength of rectangular steel tube concrete proposed in this paper is safe and reasonable,and can be used for future engineering practice. |
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