基于ISO和IEC国际规范的渤海海域桥梁冰激稳态振动响应研究

Research on Ice-induced Steady-state Vibration Response of Bridge over Bohai Sea Based on International Standard like ISO and IEC

渤海是我国冰情最为严重的海域,每年冬季约有2~4个月的结冰期,严苛的冰环境对海域内的构筑物造成了极大的威胁。就在渤海海域拟建的秦大跨海通道工程,针对其中易受冰荷载影响的深水高桩基础桥梁,结合国际上较为通用的ISO 19906:2010规范与IEC 61400-3:2009规范,采用有限元数值分析的方法,对选取桥梁结构进行了冰激稳态振动时程响应分析。分析结果表明,在桥梁结构冰激稳态振动中,因"频率锁定"现象的存在,使得桥梁结构的动态响应出现了明显的动力放大现象,这是桥梁结构在冰荷载作用下的一种极为不利受载情况,需引起足够重视;两则规范在极值静冰力接近的情况下,因动冰力荷载形式不同,所引起的桥梁结构的动态响应也存在较大差异,需进行进一步研究以得到适合于渤海域的冰荷载动力时程曲线。

Bohai Sea belongs to a sea area with the most serious ice condition in our country. There is an ice period of about 2 -4 months every year in winter. The severe ice environment may cause great threat to the structures within the sea area. Aiming at the bridge with deepwater high pile foundation that is easily influenced by ice load in the planned construction of Qinda cross-sea channel project in Bohai Sea area,and combining with international ISO 19906： 2010 standard and IEC 61400-3： 2009 standard,the analysis on the ice-induced steady-state vibration time-history response of the selected bridge structure is made by adopting the method of numerical analysis of finite element. The analysis results show that,due to the existence of ＂ frequency lock ＂ phenomenon in the ice-induced steady-state vibration of bridge structure,the dynamic response of the bridge structure has an obvious phenomenon of dynamic amplification. It is an extremely harmful supported load condition of the bridge structure under the influence of ice load,which needs enough attention. Under the condition of approximate peak ice force,due to different forms of dynamic ice force in these two standards,there is a large difference in the dynamic response of the bridge structure. Therefore,it is necessary to further study to obtain the dynamic time-history curve of ice load that is fit for Bohai Sea.