To study the mechanical behavior of flexible support cold-formed thin-walled steel frame structures under earthquake excitation, two full-scale frame models with flexible supports arranged only at the top and bottom of the frames were designed and fabricated. Shaking table tests were conducted on both models. By comparing their dynamic characteristics and responses, the influence of flexible supports on the overall seismic performance of the structures was investigated, along with numerical simulations. The results show that as the peak input excitation acceleration increases, the natural frequency of the structure decreases, while the dynamic response increases. Compared to the T₂ model, the T₁ model has greater overall stiffness, with smaller acceleration and displacement responses.Under both frequent and rare seismic events, the maximum inter-story drift angles of both models meet the code's limit requirements and demonstrate a high safety margin. The flexible support cold-formed thin-walled steel frame structures exhibit good deformation capacity and seismic performance. The finite element analysis results align well with the experimental results.

In order to study the effects of the continuous truss on the shock resistance performance of the truss-type cold-curved thin-walled steel structure, in the report, the truss position, quantity and test parts were taken into account, a two-foot-foot skeleton model was designed and constructed, the low-frequency cyclic loading test was performed to analyze the hysteretic behavior, stiffness degradation, bearing capacity deterioration, and energy consumption. The results indicated that the continuous truss structure had a good effect on improving the continuity and integrity of the skeleton model. The continuous truss structure set on the left and right sides of the opening model withstood the large horizontal loads and coordinated the deformation with the other components. Compared with the intermediate settings, the bearing capacity of the non-cave model increased by 3.4%, and the cumulative energy consumption under the same displacement condition increased by 27.5%, which suggested that the continuous truss structure can improve the bearing capacity and energy consumption performance of the test parts. The numerical analysis data of the finite element method demonstrated that when the area of the truss cross section increased from 13.2 cm² to 31.2 cm², the carrying capacity increased by 157.37%, the anti-side stiffness increased by 157.89%. Increasing the area of the truss cross section can effectively improve the seismic performance of the structural model.

In order to create a precise method for calculating the flexural bearing capacity of the new-type circular aluminium-concrete-steel double skin tubular (termed “ACSDST”), in the report, based on the plastic stress distribution method (PSDM), the theoretical derivation was performed to obtain a group of formulas for the flexural bearing capacity calculation, which can accurately account for the areas of different stress zones across the cross-section. A comparative analysis results of the obtained flexural bearing capacity of 168 ACSDST specimens and the finite element data demonstrated that the average error of the calculated values does not exceed 5.5%. Thus, these formulas can provide a good prediction for flexural bearing capacity of ACSDST sections, and which can provide the basis for their application and design.

To solve the problem of poor corrosion resistance in steel tube confined concrete, a new structural form termed aluminum alloy tube confined concrete (AATCC) has been developed. This innovation uses aluminum alloy tubes, which are known for their excellent mechanical properties and superior corrosion resistance, to replace steel tubes for confining concrete. With concrete strength (33.3, 48.7, and 66.8 MPa) as the influencing factor, three AATCC short columns with a slenderness ratio of 3 were designed and subjected to axial compression tests. The test results indicate that the failure modes of AATCC short columns exhibited shear failure characteristics, along with favorable deformation capacity and high load-bearing performance. The enhancement factor relative to the bearing capacity of plain concrete axial compression short columns increased with the confinement effect coefficient but decreased with higher concrete strength. Existing formulas for predicting the axial load bearing capacity of confined concrete were compared to evaluate their applicability to AATCC short columns.