一种四角钢组合约束型防屈曲支撑外围连接的设计方法研究:理论推导

BOLT CONNECTION BEHAVIOR AND DESIGN OF A FOUR-ANGLE ASSEMBLED STEEL BUCKLING-RESTRAINED BRACE: THEORETICAL ANALYSIS

在四角钢组合约束型防屈曲支撑中,螺栓是连系外围各个约束角钢的关键元件,在支撑发生侧向弯曲变形时承受拉力、剪力的共同作用。该文对单向弯曲变形状态下的外围螺栓内力计算方法展开了研究。首先介绍了内核构件与外围构件之间侧向挤压力的计算方法。然后,将该侧向挤压力分解为对称受力状态与反对称受力状态,螺栓在这两种受力状态中分别起到防止外围约束角钢发生分离的作用以及保持各角钢变形协调、共同抗弯的作用。基于这两种受力状态,考虑螺栓连接附近角钢板件局部变形所产生的撬力作用,经理论推导分别给出了螺栓内力的简化计算公式。再考虑螺栓内力的生成机制,对这两种受力状态分别计算得到的螺栓内力进行组合,得到了实际受力状态中螺栓内力的计算公式。最后,还介绍螺栓间距对螺栓内力的影响。

The bolts in an assembled buckling-restrained brace （ABRB） will combine the outer restraining angle steels together, and undertake tensile and shear forces while the ABRB deforms laterally. This paper presents a simplified design method for the bolt connections among angle steels, and the method is suitable for the situation that the ABRB only deforms in one direction. Firstly, the interaction between an inner core and outer restraining components is studied. Then, the reaction of the inner core to outer restraining components is decomposed into two states, namely one symmetric deformation state and one anti-symmetric deformation state. In the former state, the bolts prevent the outer angle steels from separating one another without a global lateral displacement; while in the latter state, the bolts make the angle steels bend cooperatively in the lateral and longitudinal directions. Relying on theoretical derivation, the equations to determine the bolt forces in the two states are obtained respectively, where the prying forces due primarily to local deformation of plate components of angle steel are taken into account. By the combination of the two states, the bolt forces are determined accurately. Finally, the influence of bolt distance on the amplitudes and distributions of bolt forces is introduced.