Development of Local-Buckling-Only Steel Braces based on controlled bending of U-shaped steel

IF 8.3 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures Pub Date : 2026-04-09 DOI:10.1016/j.tws.2026.114964

Emmanuel Nyabongo, Xiaohua Li, Ao Yang, Wang Zou

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Abstract

This paper proposes a new concentric steel brace for earthquake-resistant building frames, called the Local-Buckling-Only Steel Brace (LBOB), based on the controlled bending of U-shaped steel. The LBOB comprises two U-shaped steel sections connected by low-yield-point (LYP) steel plates. Under tension, the steel brace develops nearly uniform axial deformation with stable stiffness. Under compression, the U-shaped sections buckle locally in a controlled manner while LYP plates restrain lateral displacements, suppressing out-of-plane/distortional instabilities and maintaining stable hysteretic response. Cyclic tests were conducted on four proof-of-concept specimens by varying U-shaped steel section depth, flange width, and LYP plate thickness. The test results showed that three specimens achieved the intended local-buckling-only mechanism with stable hysteresis and expected energy dissipation, while one specimen with reduced flange width developed in-plane buckling. Then, a numerical investigation was conducted to take insights into the resisting mechanism and validated against the experiments, reproducing the observed buckling modes and predicting strengths with relative errors ranging from 0.13% to 7.35%. Elastic stiffness predictions based on an effective yielding length showed good agreement with the measured values, with an average of 1.04. The effective compressive yield occurred within the range of 71 to 98% of the stable peak compressive resistance, which shows post-buckling strengthening and geometry sensitivity. The proposed brace design shows significant sensitivity to geometry and detailing, indicating that optimization of U-shaped steel sections and configuration of LYP plates is crucial to balance strength, stability, and energy dissipation for seismic applications.

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基于u型钢控制弯曲的局部屈曲钢支撑的研制

本文提出了一种基于u型钢控制弯曲的新型抗震建筑框架用同心钢支撑，即局部屈曲钢支撑（LBOB）。LBOB由两个u型钢组成，由低屈服点（LYP）钢板连接。受拉作用下，钢支撑轴向变形接近均匀，刚度稳定。受压时，u型截面局部屈曲可控，而LYP板抑制侧向位移，抑制面外/变形不稳定，保持稳定的滞回响应。通过改变u型钢截面深度、法兰宽度和LYP板厚度，对四个概念验证试件进行了循环试验。试验结果表明，3个试件达到了预期的局部屈曲机制，具有稳定的滞回和预期的能量耗散，而减小翼缘宽度的1个试件出现了面内屈曲。然后，进行了数值研究，以深入了解抵抗机制，并与实验进行了验证，再现了观察到的屈曲模式，并预测了相对误差在0.13%至7.35%之间的强度。基于有效屈服长度的弹性刚度预测值与实测值吻合较好，平均值为1.04。有效抗压屈服发生在稳定峰值抗压阻力的71% ~ 98%范围内，表现出屈曲后强化和几何敏感性。所提出的支撑设计对几何形状和细节非常敏感，这表明u形钢截面的优化和LYP板的配置对于抗震应用中平衡强度、稳定性和能量耗散至关重要。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Thin-Walled Structures 工程技术-工程：土木

CiteScore

9.60

自引率

20.30%

发文量

801

审稿时长

66 days

期刊介绍： Thin-walled structures comprises an important and growing proportion of engineering construction with areas of application becoming increasingly diverse, ranging from aircraft, bridges, ships and oil rigs to storage vessels, industrial buildings and warehouses. Many factors, including cost and weight economy, new materials and processes and the growth of powerful methods of analysis have contributed to this growth, and led to the need for a journal which concentrates specifically on structures in which problems arise due to the thinness of the walls. This field includes cold– formed sections, plate and shell structures, reinforced plastics structures and aluminium structures, and is of importance in many branches of engineering. The primary criterion for consideration of papers in Thin–Walled Structures is that they must be concerned with thin–walled structures or the basic problems inherent in thin–walled structures. Provided this criterion is satisfied no restriction is placed on the type of construction, material or field of application. Papers on theory, experiment, design, etc., are published and it is expected that many papers will contain aspects of all three.