摘要
地震动在强度和频率等方面均具有非平稳特性,导致多跨桥梁的动力响应非常复杂。为了研究多跨连续桥梁在多点地震动激励下的反应,首先提出了评价多点地震动非平稳性的3个指标:幅值绝对值的标准差、方向离散度和穿零率。根据桥梁多点激励运动方程的特点,阐述了广义振型参与系数矩阵的意义,及其与传统振型参与系数矩阵的联系和区别。根据多点地震动非平稳性的特性,对不同支点施加异向及不同幅值的位移或加速度,研究了不同跨数连续梁桥的多点激励响应规律。结果表明,随着连续梁桥跨数的增多,桥梁在多点地震激励下的响应趋于复杂多变,受具体地震动的非平稳性影响越发明显。
The earthquake motion has non-stationarity both in strength and frequency,and it make the dynamic responses of multi-span bridges be complex and severe.To study the responses of continuous bridges under multi-support excitations,three indexes are presented：the standard deviation of absolute amplitudes,the direction dispersion and the crossing-zero rates.The significance of the general matrix of modal participation factor is represented according to the characteristics of the structural motion equations under multi-support excitations.The regularity of the responses of different span continuous bridges under excitations is studied by applying the displacements or accelerations with different directions or amplitudes on each supports.The results show that the responses become more complex and various with the increasement of the span number and the non-stationarity in earthquake excitations.
出处
《防灾减灾工程学报》
CSCD
2011年第1期44-49,共6页
Journal of Disaster Prevention and Mitigation Engineering
基金
国家自然科学基金重大研究计划重点项目(90715032)资助
关键词
非平稳特性
多点激励
穿零率
振型参与系数
连续梁桥
non-stationary
multi-support excitations
crossing-zero rates
modal participation factor
continuous bridge
