考虑土-结构相互作用下桥梁震动的半主动控制研究

Study on Semi-Active Vibration Control of Bridge Considering Soil-Structure Interaction

研究了考虑土-结构相互作用下桥梁结构的MRD半主动震动控制.将桥梁结构简化成14自由度模型,作动器布置在桥台和主梁之间.采用子结构方法考虑土-结构之间的相互作用.为简化计算,地基阻抗函数采用与激励频率无关的时域阻抗函数.分别用LQR和H_∞控制算法控制桥梁结构的响应.研究表明:在场地土较弱时,土-结构相互作用明显改变结构的动力特性,对桥梁结构的MRD半主动控制的控制效果有重要的影响;控制理论设计的控制器更具有鲁棒性,在剪切波速较大时,控制效果和LQR半主动控制接近;在剪切波速较小时,仍然对桥梁结构有控制效果,而LQR半主动控制的控制效果变差,甚至是增大结构的响应.

Considering the soil-structure interaction, the MRD semi-active control for vibration control of a seismically excited bridge was presented. The bridge was simplified to be a 14-DOF model, while actuator was fixed between the abutment and girder of the bridge. Sub-structure method was applied to consider the soil-structure interaction. Frequency-independent impedance of soil-structure systems was adopted. LQR and H∞ control algorithms were applied to control the response of bridge structure, respectively. Results show that： soil-structure interaction changes the dynamic characteristics of structure and can significantly affect the MRD semi-active control of the bridge structure when the field is weak; the controller designed by H_∞ control theory is more robust when shear wave velocity is fast, the effect of LQR and H∞ semi-active control is almost the same; when the shear wave velocity is slow, H∞ semi-active control is still taking effect, however, the effectiveness of LQR semi-active control is degrading, regardless of the increase of structure response.