【摘要】 为了研究高阶模态对底部带BRB的铰支墙(HWBB)框架结构的影响,建立了HWBB-铰接框架和HWBB-抗弯框架的分布参数模型.将铰支墙简化为弯曲梁、BRB简化为转角弹簧、抗弯框架简化为剪切梁.推导出2种分布参数模型的振动方程,求出各阶周期、各个振型及内力和位移的数值解.研究了相对刚度比以及转动刚度比对高阶模态效应的影响.对于弹性结构,整体位移及抗弯框架中的剪力由一阶模态控制,而墙中的剪力和弯矩受高阶模态影响较大.同时研究了BRB屈服对HWBB-铰接框架结构内力分布的影响.结果表明:在BRB屈服后,原一阶模态将不再对内力产生贡献,而高阶模态对内力贡献作用将增加.但BRB屈服后位移对高阶模态不敏感、仍由一阶模态控制.参数分析表明:在墙的抗弯刚度达到一定值前,随着墙抗弯刚度的增加,结构的位移会逐渐减小;随着转动刚度的增加,前三阶周期会减小;随着转动刚度比的增加,一阶模态的基底剪力贡献系数减小,但二阶和三阶模态的基底剪力贡献系数增加.更多还原

【Abstract】 To investigate the effect of higher modes on the displacement and inner forces in HWBB(hinged wall with buckling-restrained braces in base)-frame structure, distributed parameter models for both the HWBB-hinged frame structure and the HWBB-MRF(moment resisting frame) structure are built. The hinged wall is simplified as a flexural beam. BRBs(bucking-restrained braces) are simplified to a rotational spring. MRF is simplified to a shear beam. Vibration equations of distributed parameter models are derived. Natural periods, natural modes of vibration, inner forces and displacements of the distributed parameter models are derived based on the vibration equations using numerical methods. The effect of the relative stiffness ratio and the rotational stiffness ratio on the higher mode effects is investigated. For elastic structures, the global displacement and shear in MRF are predominantly controlled by the first mode, while the shear and bending moment in the wall are significantly affected by higher mode effects. The effect of the yielding of BRB on the inner forces distribution in the HWBB-hinged frame is investigated. The results indicate that the first mode will no longer contribute to the inner forces and the contribution from higher modes to inner forces increases after the BRBs yield. Displacement is not sensitive to higher mode effects and it is controlled by the first mode after the BRBs yield. Parameter analysis demonstrates that the displacement amplitudes are reduced with the increase in the flexural stiffness of the wall before the flexural stiffness reaches a certain value. The first three periods decrease with the increase in the rotational stiffness. With the increase in the rotational stiffness ratio, the contribution from the first mode decreases while contributions from both the second mode and third mode increase.更多还原