Zhuojin Pipe Fitting Co., LtdHysteresis Performance of Square Steel Tube Concrete Frame with Vertically Stiffened Thin Steel Plate Shear Wall
Literature Overview
This study, published in Journal of Xi'an University of Architecture and Technology (Natural Science Edition) (2017, Vol. 49, No. 5, pp. 637–645) by Wang Xiantie, Jia Guiqiang, Li Jin, Chen Fengmei, Luo Yao, and Zheng Jiang from Xi'an University of Architecture and Technology, investigates the hysteresis performance of a square steel tube concrete frame combined with vertically stiffened thin steel plate shear walls. The research was supported by the National Natural Science Foundation of China (51678474) and the Shaanxi Provincial Natural Science Foundation (2015JM5170). A 1/3 scale single-bay two-story model was subjected to low-cycle reversed loading, and nonlinear finite element analysis using ABAQUS was conducted to complement the experimental results.
Core Technical Findings
The study systematically investigates the effects of four key parameters on the hysteresis performance of the composite structural system: column axial compression ratio, number of stiffening ribs, steel plate wall height-to-thickness ratio, and column flexibility coefficient.
Parametric Study Results
| Parameter | Effect on Load-Bearing Capacity | Effect on Energy Dissipation | Effect on Stiffness Degradation | Effect on Ductility |
|---|---|---|---|---|
| Column axial compression ratio | Decreases with increase | Slight decrease | Slight effect | Decreases with increase |
| Number of stiffening ribs | Slight effect | Significant increase | Slight effect | Moderate increase |
| Steel plate wall height-to-thickness ratio | Decreases with increase | Decreases with increase | Increases with increase | Decreases with increase |
| Column flexibility coefficient | Decreases with increase | Decreases with increase | Increases with increase | Decreases with increase |
Hysteresis Loop Characteristics
The experimental and numerical results demonstrate that the square steel tube concrete frame with vertically stiffened thin steel plate shear wall exhibits favorable seismic performance characteristics:
- Full and stable hysteresis loops: The structure exhibits well-developed hysteresis loops with good energy dissipation capacity.
- Progressive stiffness degradation: Stiffness degrades gradually with increasing displacement, indicating a ductile failure mechanism.
- Distributed damage: Damage is distributed across multiple components rather than concentrated at a single location.
- Post-yield ductility: The structure maintains load-bearing capacity well beyond the initial yield point.
Technical Interpretation and Engineering Relevance
From a steel pipe engineering perspective, this study addresses the design of composite lateral force resisting systems that combine the compression capacity of steel tube concrete columns with the shear resistance of thin steel plate walls. The vertically stiffened thin steel plate shear wall is a lightweight alternative to conventional reinforced concrete shear walls, offering reduced weight and faster construction.
Key Design Principles
- Column axial compression ratio control: The finding that increased axial compression ratio reduces ductility is consistent with general structural engineering principles. For steel tube concrete columns, the axial compression ratio should be limited to maintain sufficient ductility for seismic performance. Typical design limits are:
- Elastic design: axial compression ratio ≤ 0.4
- Plastic design: axial compression ratio ≤ 0.6
- Stiffening rib optimization: The significant effect of stiffening rib number on energy dissipation highlights the importance of proper stiffener design for thin steel plate walls. The stiffening ribs prevent local buckling of the steel plate and promote membrane action, which is the primary mechanism for shear resistance and energy dissipation.
- Steel plate wall slenderness control: The height-to-thickness ratio of the steel plate wall is a critical design parameter. Excessive slenderness leads to premature local buckling and reduced energy dissipation capacity. Design guidelines suggest:
- Height-to-thickness ratio ≤ 100: Full membrane action
- Height-to-thickness ratio 100–200: Partial membrane action
- Height-to-thickness ratio > 200: Local buckling dominates
- Column flexibility coefficient: The flexibility coefficient of the steel tube concrete columns affects the overall system behavior. Stiffer columns transfer more shear demand to the steel plate wall, potentially leading to premature failure. A balanced design is essential.
Welding and Fabrication Considerations
For the steel tube concrete columns used in this system, the following welding and fabrication considerations are critical:
- Longitudinal weld quality: The longitudinal weld in the square steel tube must be free of defects to ensure proper concrete infill and structural integrity.
- Circumferential weld integrity: Welds at column ends and beam-column joints must be designed for ductile behavior under cyclic loading.
- Stiffening rib welds: The welds connecting the stiffening ribs to the steel plate wall must be designed to prevent weld fracture under cyclic loading.
- Surface preparation for concrete infill: The interior surface of the steel tube must be clean and free of contaminants to ensure proper bond between the steel and concrete.
Study Insights and Implications
This research provides valuable insights into the seismic design of hybrid structural systems that combine steel tube concrete frames with thin steel plate shear walls. The vertically stiffened thin steel plate wall concept offers a lightweight alternative to conventional shear walls, with potential advantages in terms of construction speed, material efficiency, and architectural flexibility.
The parametric study results provide practical design guidelines for optimizing the seismic performance of such systems. The finding that stiffening rib number has a significant effect on energy dissipation but limited effect on load-bearing capacity suggests that the number of stiffening ribs should be selected based on energy dissipation requirements rather than strength requirements.
The combination of experimental testing and nonlinear finite element analysis provides a comprehensive understanding of the structural behavior. The ABAQUS-based numerical model can be used for detailed design analysis and parametric studies beyond the scope of physical testing.
From a practical standpoint, this type of structural system is particularly suitable for mid-rise buildings where the combination of gravity load resistance and lateral load resistance is required. The steel tube concrete columns provide efficient gravity load resistance, while the thin steel plate shear walls provide lateral load resistance with minimal additional weight.
The study also highlights the importance of considering the interaction between different structural components in seismic design. The performance of the overall system depends on the compatibility of deformation between the steel tube concrete columns and the steel plate shear wall. Proper detailing of the connections between these components is essential to ensure that the system performs as intended under seismic loading.