强震作用下采用BRB的联塔斜拉桥力学响应分析

Analysis on Mechanical Response of Double-pylon Cable-stayed Bridge with BRB under Strong Earthquake

摘要:

以位于抗震设防烈度为8度的高烈度地震区中的（151+328+151）m联塔斜拉桥为研究对象，拟在联塔间设置大吨位屈曲约束支撑（Buckling-Restrained Brace，BRB），以提高联塔结构的连接刚度与地震耗能能力。分析在强震作用下联塔结构的内力变化，量化BRB的弹性刚度、屈服力及屈服后刚度等关键力学参数的敏感性大小，对BRB关键参数的取值提出合理化建议。研究结果表明：结构内力对BRB初始刚度变化敏感性较大，故BRB初始刚度应维持在设计值；结构内力对BRB屈服力有一定的敏感性，故BRB屈服力宜维持在设计值或适当提高；联塔结构内力对BRB屈服后刚度敏感性较小，故BRB屈服后刚度宜维持在设计值或较低水平。

Abstract:

Taking a (151+328+151) m double-pylon cable-stayed bridge located in a high-intensity earthquake area with seismic fortification intensity of 8 degrees as the research object, it is proposed to install the large-tonnage buckling-restrained braces (BRB) between the pylons to improve the connection stiffness and seismic energy dissipation capacity of the double-pylon structure. The internal force changes of double-pylon structures under strong earthquake action are analyzed. The sensitivity of key mechanical parameters such as elastic stiffness, yield force, and post yield stiffness of BRB is quantified. And the rational suggestions for the values of key parameters of BRB are put forward. The research results indicate that the internal forces of the structure are highly sensitive to changes in the initial stiffness of the BRB, and the initial stiffness of the BRB should be maintained at the design value. The internal forces of the structure have a certain sensitivity to the yield force of BRB, and the yield force of BRB should be maintained at the design value or appropriately increased. The internal forces of the double-pylon structure are less sensitive to the stiffness of the BRB after yielding, and the stiffness of the BRB after yielding should be maintained at the design value or a lower level.