超高层建筑施工塔吊的动力特性和地震响应规律研究

由于施工塔吊的广泛性和周转使用期限为20年甚至更长,致险地震发生概率也会相应增加。为了研究超高层建筑施工塔吊抗震性能,通过对某实际工程中的动臂式塔吊进行了现场监测并获取其实测自振频率,同时以此为依据对塔吊有限元模型进行有效修正。在此基础上,为了探究超高层建筑在施工过程中塔吊的地震响应规律,分析地震作用下超高层建筑与塔吊的耦合效应,结果表明,超高层建筑—塔吊模型存在多个共振区域,滤波后的时程分析进一步验证该结论。在超高层建筑施工过程中,塔吊爬升过程中有两次地震响应放大现象,需要重视其抗震性能的动态变化。探讨塔吊的动力特性随施工过程的动态发展规律和破坏效应,发现塔吊的应力热区集中在塔身的顶部和起重臂根部,在大震下易出现相应位置的弯折破坏。

SEISMIC RESPONSE AND DYNAMIC CHARACTERISTICS OF CRANES ON HIGH-RISE BUILDINGS

The probability of earthquake will increase, because of the universality and the crane use for a period of 20 years or even longer. In order to study the dynamic seismic performance of the tower crane in the construction of the super high-rise building, on-site monitoring is conducted to a boom tower crane used in the actual project. The stochastic subspace identification method is used to obtain the measured natural frequency of the tower crane structure, which is the basis to effectively modify the finite element model of tower crane structure. On the basis of this, considering the coupling effect of the super high-rise building and the tower crane under earthquake action, the resonance area analysis of the super-high-rise building-tower crane model is carried out and the conclusion is further verified by the filtering method to explore the seismic response of the tower crane during the construction process. The results show that there are two seismic response magnifications during the climbing process of the super high - rise building, and attention should be paid to the dynamic change of seismic performance. By discussing the dynamic development of dynamic characteristics with construction and destruction effect of the tower crane, it is found that the stress hot zone of the tower crane is concentrated at the top of the tower and the root of the boom, and the bending of the corresponding position is easy to occur under the earthquake.