装配式开孔不锈钢防屈曲支撑抗震性能试验研究

EXPERIMENTAL STUDY ON SEISMIC BEHAVIOR OF ASSEMBLED BUCKLING-RESTRAINED BRACE WITH PERFORATED STAINLESS-STEEL PLATE

  • 摘要: 为提升沿海工程结构中耗能构件的耐久性能,提出了装配式不锈钢防屈曲支撑(BRBs),分别采用奥氏体S304和双相型S2205不锈钢作为内芯板。对内芯板和外约束板进行开孔设计,实现定点耗能的同时方便震后对BRBs的损伤情况进行观察。通过拟静力试验分析了不同材质BRBs的滞回特性及抗震性能,并采用ABAQUS对试验进行了模拟。结果表明:设计的装配式开孔一字形BRBs,结构形式简单,整体稳定性好。不同材质BRBs的屈服后硬化程度差异较大,建议对奥氏体S304不锈钢BRBs刚度因子取0.1,双相型S2205不锈钢BRBs刚度因子取0.02。两种不锈钢BRBs的等效粘滞阻尼比在L/100位移幅值下为0.4左右,均表现出了良好的耗能能力。在相同加载位移幅值下,奥氏体S304和双相型S2205不锈钢BRBs,与屈服强度分别相近的Q235和Q550普通钢BRBs相比,在低周疲劳寿命、塑性变形能力和总耗能等方面都分别远高于后者,具有更优的抗震性能。拟合得到的内芯板循环本构参数能够描述BRBs的滞回特性,采用的建模方法能够兼顾计算精度和计算效率。

     

    Abstract: To improve the durability of energy dissipation members in coastal engineering structures, assembled stainless steel buckling-restrained braces (BRBs) are proposed, and its inner core plate is made of austenitic S304 and duplex S2205 stainless steel respectively. The inner core plate and outer restraint plate are perforated to achieve fixed energy dissipation and facilitate the observation of the damage to the brace subsequent to an earthquake. The hysteretic characteristics and seismic performance of BRBs with different materials are analyzed through the pseudo-static test, and the cyclic loading test was simulated by ABAQUS. The results show that the prefabricated BRBs with the perforated flat panel have a simple structure style and a good performance of overall stability. The hardening degree of the BRBs with different inner core materials varies greatly. It is suggested that the stiffness factor of austenitic S304 stainless steel BRBs should be 0.1 and that of duplex S2205 stainless steel BRBs should be 0.02. The equivalent viscous damping ratio of both stainless steel BRBs is about 0.4 under the L/100 displacement amplitude, which shows good energy dissipation capacity. Under the same loading regime, the fatigue life, plastic deformation capacity and total energy dissipation of stainless steel BRBs are much higher than those of Q235 and Q550 ordinary steel BRBs with similar yield strength respectively, which presents better seismic performance. The fitted cyclic constitutive parameters of the inner core plate can describe the hysteretic characteristics of BRBs, and the modeling method adopted can consider both computational accuracy and computational efficiency.

     

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