软土地基上的土-结构动力相互作用
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摘要
对于建在软弱地基土上的高层结构,由于土-结构动力相互作用,基础的平移和转动导致结构整体发生刚体位移,特别是刚体运动中的转动不仅可能增加结构的绝对位移,并且可能加大结构的重力倾覆力矩,使结构的整体稳定性受到影响。以软土地基上的刚性基础及上部结构为研究对象,通过施加与重力倾覆力矩等效的侧向力来考虑重力二阶效应,并推导了考虑土-结构动力相互作用时结构的几何刚度矩阵。数值算例表明,土-结构动力相互作用对结构的位移产生较大的影响,由此所引起的重力二阶效应可能使结构抗倾覆性能偏于不安全。
For a tall building structures built on soft soil, the rigid body displacement of the structure will occur due to the soil-structure dynamic interaction under strong ground motion. Particularly rotation of the foundation in the rigid body movement may not only increase structural absolute displacement, but also enlarge the gravity overturn moment on the structure, and reduce the safety of the whole stability of the structure. Taking the stiff foundation on soft soil and supper-structure as the research object, this paper develops a method for analyzing the gravity second order effect, in which the gravity P-△ effect is considered by a set of lateral forces on the structure and is equivalent with the overturn moment. And the geometry stiffness matrix of the structure is established based on the soil-structure dynamic interaction. Numerical examples illustrate the effect of soil-structure interaction on the structures, and deformations of a structure compared with rigid body displacement under gravity second order action.
For a tall building structures built on soft soil, the rigid body displacement of the structure will occur due to the soil-structure dynamic interaction under strong ground motion. Particularly rotation of the foundation in the rigid body movement may not only increase structural absolute displacement, but also enlarge the gravity overturn moment on the structure, and reduce the safety of the whole stability of the structure. Taking the stiff foundation on soft soil and supper-structure as the research object, this paper develops a method for analyzing the gravity second order effect, in which the gravity P-△ effect is considered by a set of lateral forces on the structure and is equivalent with the overturn moment. And the geometry stiffness matrix of the structure is established based on the soil-structure dynamic interaction. Numerical examples illustrate the effect of soil-structure interaction on the structures, and deformations of a structure compared with rigid body displacement under gravity second order action.
引文
[1]GB 50011-2001,建筑抗震设计规范[S]．
[2]George Mylonakis, George Gazetas. Seismic soil structure interaction: beneficial or detrimental[J].Journal of Earthquake Engineering, 2000,4(3) :277 -301.
[3]林皋．土-结构动力相互作用[J]．世界地震工程,1991,(3):4 -21．
[4]曹志远．结构与介质相互作用分析理论及其应用[M]．南京:河 海大学出版社,1993．
[5]梁青槐．土-结构动力相互作用数值分析方法的评述[J]．北方交 通大学学报,1997,21(6):690-694．
[6] Lysmer J, Richart, F E Jr. Dynamic response of footing to vertical loading[J]. Journal of Soil Mech Div ASCE, 1966,92(1): 65-91.
[7]唐胡乐,黄穗宁．地基-基础 上部结构耦合系统的动力相互作用 浅析[J]．工程抗震,2002,(1):8-14．
[8]蒯行成,沈蒲生,陈军．地基-简体结构的地震反应分析[J]．湖 南大学学报,1997,24(4):79-85．
[9]熊建国．土-结构动力相互作用问题的新进展[J]．防护工程, 1993,(3):27-39．
[10]汪梦甫．钢筋混凝土高层结构抗震分析与设计[M]．长沙:湖南 大学出版社,1999．
[2]George Mylonakis, George Gazetas. Seismic soil structure interaction: beneficial or detrimental[J].Journal of Earthquake Engineering, 2000,4(3) :277 -301.
[3]林皋．土-结构动力相互作用[J]．世界地震工程,1991,(3):4 -21．
[4]曹志远．结构与介质相互作用分析理论及其应用[M]．南京:河 海大学出版社,1993．
[5]梁青槐．土-结构动力相互作用数值分析方法的评述[J]．北方交 通大学学报,1997,21(6):690-694．
[6] Lysmer J, Richart, F E Jr. Dynamic response of footing to vertical loading[J]. Journal of Soil Mech Div ASCE, 1966,92(1): 65-91.
[7]唐胡乐,黄穗宁．地基-基础 上部结构耦合系统的动力相互作用 浅析[J]．工程抗震,2002,(1):8-14．
[8]蒯行成,沈蒲生,陈军．地基-简体结构的地震反应分析[J]．湖 南大学学报,1997,24(4):79-85．
[9]熊建国．土-结构动力相互作用问题的新进展[J]．防护工程, 1993,(3):27-39．
[10]汪梦甫．钢筋混凝土高层结构抗震分析与设计[M]．长沙:湖南 大学出版社,1999．
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