The mechanical properties of a Tou-Kung joint located on the external column of the third floor of Guang-yue Tower were studied through experimental and theoretical methods. In this article, three scaled models of the Tou-Kung joint used in the Guang-yue Tower were designed according to actual configurations; they were tested and analyzed. The quasi-static tests were conducted under different vertical loads of 25, 50 and 75 kN. The failure modes, hysteresis curves, skeleton curves and rigidity-displacement curves were obtained. The results show that the failure mode of the Tou-Kung joint is a brittle failure of the Lu-Tou type, and the horizontal bearing force increased as the vertical load increased. The hysteretic curves appeared to have a reverse S shape, and they were relatively full, indicating a significant energy consumption ability. The horizontal rigidity increased with the increase of the vertical load but decreased with the increase of displacement. The horizontal load applied to the Tou-Kung joint model was shared by Fang components, and the frictional force was applied between the flower arms and the main exposed tie beam, based on which the method for calculating the rigidity-displacement method was deduced based on the embedment deformation theory of wood, and the calculated result was found to correspond to the experimental data.

In Song dynasty, Dou-Gong construction techniques, Tou-Xin-Zao and Ji-Xin-Zao, varied by the number of Fang connecting to the exterior. This study examines the impact of Fang connections on the mechanical characteristics of Dou-Gong. Six full-scale models were constructed and subjected to quasi-static loading tests in the horizontal Beam and Fang directions under vertical load. The hysteresis behavior, deformation, and stiffness variations were obtained and analyzed. The test results revealed the hysteresis curve of Dou-Gong developed into a flat shape, with good deformation recovery ability and seismic performance. Beam-direction loading led to brittle failure, with Dou-Gong having fewer Fang experiencing bearing capacity loss and those with more Fang succumbing to overturning. Beam-direction stiffness rose by approximately 29% as the number of connecting Fang increased. Fang-direction loading induced ductile failure, predominantly characterized by overturning. Notably, Fang-direction stiffness remained largely unchanged by the varying number of connecting Fang. Dou-Gong slip deformation ratio decreased by 5 -10% as the number of Fang increased. Furthermore, Fang-direction exhibited about 10% greater slip deformation capacity than the Beam-direction. Based on the force transfer mechanism of Dou-Gong components, a stiffness formula for the elastic stage of Dou-Gong in the Beam-direction and Fang-direction was established and validated against experimental data.

In this paper, the eccentric compression test of seven specimens was conducted to explore the application possibility of recycled aggregate concrete (RAC) in L-shaped columns composed of concrete-filled steel tubes (CFST). The main parameter is the replacement ratio of recycled coarse aggregates (RCA), and an L-shaped column of composed hollow steel tubes was set as a control. The test results indicated that the bearing capacity and stiffness of the L-shaped column composed of RAC-filled steel tubes (RACFSTs) are better than those of the L-shaped column composed of hollow steel tubes. The compressive strength of concrete is reduced by 73.1% as the replacement ratio of RCA increases from 0 to 100%, while that of the column is merely reduced by 23.9%. The strength disadvantage of RAC is compensated by the confinement of steel tubes. Besides, the result of the eccentric compression test (80 mm eccentricity) was compared with the axial compression test (0 mm eccentricity). The increase in eccentricity reduced the bearing capacity and ductility due to additional bending moments. The finite element model (FEM) was established by software ANSYS to compare with the experimental results. The bearing capacity deviation of FEM is 4.23~6.56%. The parametric analysis was carried out to summarize the influence of parameters such as eccentricity, material strength, and steel tube thickness. With the increase of eccentricity, the bearing capacity of the RACFST decreases gradually. In engineering design, the bearing capacity of the RACFST can be improved by increasing the strength and thickness of the steel.

The quasi-static experiments and finite element analysis of three groups of special-shaped concrete-filled steel tube (SCFST) column chevron braced frames (two groups of eccentrically braced frames and one group of concentrically braced frame) were carried out. The differences of quasi-static mechanical properties between the three groups frame were compared. The damage mechanism of the concentrically and eccentrically braced frames was significantly different, and the eccentrically braced frame could significantly improve the energy-dissipation ability and ductility. When the single limb of columns was connected by double-steel-plate, the stiffness of eccentrically braced structure could be improved around 10.4% and showed better energy-dissipation capacity. The finite element simulation was built on the basis of experiments, and parametric analysis was examined. The analysis results showed that section forms of the SCFST column and the thickness of brace have significant impacts on the quasi-static properties of such type of structure.