To study the seismic performance of a super high-rise building, a shaking table test with a geometrical scale of 1/35 was carried out. Part of frames in the tower structure of the building are supported by two concrete-filled steel tubular (CFST) mega frame columns with duplex-story height, which are not connected to the first 6 floors. The inclined CFST column transfer structure is arranged on the 7th to 11th floors. Through experiments, failure modes, natural vibration period, story drift, and torsional responses of the structural model were studied first. Then, a numerical analysis of the elastic-plastic seismic response of the original structure was carried out via PERFORM-3D software. Results show that torsion effects were significant because of the asymmetric plane arrangement and the inadequate torsional stiffness of the tower. When the actual peak acceleration on the shake table surface was close to the value of the rare earthquake condition (i.e., 470 cm/s2), the torsional failure occurred in the tower. In this condition, except for very few stories, the story-drift angle of each floor was still smaller the limit value 1/100 of the elastic-plastic story-drift angle. Under all load conditions, the strains of CFST frame columns and inclined ones of the transfer areas stayed elastic. The analysis results are in good agreement with those of experiments. ... Read more

To investigate the aseismic behavior of steel-jacket strengthened columns with recycled aggregate concrete, low-cycle reversed loading tests were conducted on one normal reinforced concrete column and nine steel-jacket strengthened columns with recycled aggregate concrete. Then in ABAQUS, using the fiber beam model verified by experiments, the numerical simulation on steel-jacket strengthened columns was conducted, and the related influencing factors were analyzed by parametric analysis. The results show that the aseismic behavior of columns is significantly improved by taking this strengthen scheme. Based on the range of parameters adopted in this research, the lateral resistance capacity increases with the increase of axial compression ratio in a range less than 0.58, but it decreases obviously and the degree of damage develops faster with the increase of axial compression ratio in a range larger than 0.58. The aseismic performance can be improved by increasing the thickness of steel-jacket, but the effect gradually decreases with the increase of thickness. The axial compression ratio of the original column has a great influence on the mechanical properties and failure modes of the strengthened column, and the initial compressive-bending stress significantly reduces the flexural capacity of the strengthened columns which have high axial compression ratio. When the strengthened column is under the effective constraint of steel-jacket, the influence of recycled aggregate concrete on the overall bearing capacity of columns is not obvious, but it would lead to the decrease of aseismic performance. ... Read more