Analysis of the global tall buildings stability in flat slabs considering the soil structure interaction

Abstract The global stability of tall reinforced concrete buildings made up of flat slabs is guaranteed, among other factors, by the existence of considerably rigid elements such as elevator cores and stairways. Such rigid cores recurrently have the "L" or "U" format because they fit the architectural design better. However, it should be emphasized the considerable relevance and influence of the slabs transversal bending stiffness in the building stability. The slabs act in conjunction with the columns in the building stability, in the so-called rigid diaphragm effect. That is, they combine the horizontal displacements in each floor and promote a partial restriction to the warping of the rigid cores and the rotation of the ends of the columns, thus reducing the horizontal displacements and the effects of 2nd order. In contrast the slabs transversal bending stiffenes, it should be emphasized the importance of considering the soil-structure interaction (ISE) in the buildings stability. In buildings formed by flat slabs ISE gains considerable relevance because of their characteristics, ie such buildings are particularly sensitive to the influences of soil-structure interaction. In this work, emphasis is placed on the influence of cross-bending rigidity on slabs and on Soil-Structure Interaction in the analysis and verification of the global stability of multi-storey buildings formed by flat slabs and rigid cores.

摘要 由无梁楼盖（flat slab）构成的高层钢筋混凝土建筑，其整体稳定性除其他影响因素外，主要由电梯井核心筒（elevator core）与楼梯间等刚度显著的构件保障。这类刚性核心筒通常采用L形或U形布局，以更好适配建筑设计需求。但需强调的是，楼盖横向弯曲刚度对建筑整体稳定性同样具有显著影响与相关性。在所谓的刚性隔板效应（rigid diaphragm effect）中，楼盖与柱协同作用保障建筑稳定性：具体而言，楼盖可整合各楼层的水平位移，并对刚性核心筒的翘曲变形与柱端转动形成部分约束，从而降低水平位移与二阶效应（2nd order）。相较于楼盖横向弯曲刚度的影响，还需强调在建筑稳定性分析中考虑土-结构相互作用（Soil-Structure Interaction，简称ISE）的重要性。对于采用无梁楼盖的建筑而言，土-结构相互作用的相关性显著提升，这是由于该类建筑的结构特性使其对土-结构相互作用的影响尤为敏感。本研究重点探讨了楼盖横向弯曲刚度以及土-结构相互作用，对由无梁楼盖与刚性核心筒组成的多层建筑整体稳定性分析与验证的影响。