Finite Element Analysis On Mechanical Behavior Of Circular Steel Tube—Steel Reinforced PP ECC Connections

In this paper, at first the latest developments on the application of PP ECC materials (high tenacity polypropylene fiber reinforced engineered cementitious composites) in practical engineering and its theoretical research findings and status at home and abroad were elaborated. The material property advantages of PP ECC materials were summarized, application of PP ECC in engineering field and its development trend were introduced, and the necessity of studying circular steel tube—steel reinforced PP ECC connections was proposed. In the steel PP ECC composite structures, two materials of different properties and sizes can enhance advantages and minimize disadvantages. At present, there have been a lot of theoretical researches on circular steel tube—steel reinforced concrete (SRC) at home and abroad, and a large number of engineering projects have adopted this structure, thus it can be seen that studies on this regard have been relatively complete. However, due to the natural defects of concrete, the performance of both the tube and concrete are seriously affected in the circular steel tube—SRC structure, especially in dealing with the earthquakes, its easy-cracking shortcomings is prone to greatly reduce its mechanical behavior. Circular steel tube—steel reinforced PP ECC beam-column connections use PP ECC to replace the core area concrete and to fill in the circular steel tube together with the steel reinforcements, which is a perfect combination of a new material and a high-performance heavy-load column. Theoretical studies have shown that when the PP ECC material is filled in the circular steel tube together with the steel reinforcements instead of high-strength concrete, the ultimate load-bearing capacity, ductility and energy dissipation of column can once again be increased, the shear diagonal crack generation on high-strength concretes can be largely delayed or inhibited and brittle fracture generation can be prevented, moreover, PP ECC has certain self-repair capacity on cracks. Therefore, the participation of PP ECC materials can greatly improve the earthquake resistance of columns, and avoid structural damage or even collapse; therefore, this form of combination column is very suitable to be applied in the architectural structure of high-rise buildings or seismic hazard zones. In this paper, the following researches were conducted:In this paper, the ANSYS finite element analysis software was applied to build a set of circular steel tube—SRC beam-column connections with circular steel tube filled with C60concrete as core concrete material, and circular steel tube—steel reinforced PP ECC beam-column connections with circular steel tube filled with PP ECC, and statics analysis and mechanical property analysis of cyclic load were performed on them respectively. Their load-bearing capacity, ductility and energy dissipation were studied, concluding that PP ECC was better than the concrete at the same level in terms of load-bearing capacity, ductility and energy dissipation, especially in terms of ductility and energy dissipation, PP ECC was far superior to the concrete at the same level, which is very beneficial for use in the high-intensity earthquake zones and high-rise building structures. Moreover, the circular steel tube—steel reinforced PP ECC structure can truly fulfill the concept of safety, economic, and environmental, and has great development prospects.