Influence Of Soil-Structure Dynamic Interaction On Structural Control

Structural engineers often suppose that the base is fixed while designing astructural control system. This is applicable if the base is of high rigidity, but notreasonable when the base is relatively soft. The main goal of this dissertation is toremove these presuppositions and to consider the influence of soil-structure dynamicinteraction (SSI) on structural control. The main works of this paper are as following: Firstly, the development and history of structural control and soil-structuredynamic interaction are summarized briefly, and the necessity of the analysis ofstructural control considering soil-structure interaction is emphasized. Then, theformulas of three kinds of structural control system are further deduced, includingactive tuned mass damper (ATMD), multiple tuned mass damper (MTMD) andmagnetorheological damper (MR). A 36-storied structure's reaction to El-Centrowave is simulated via MATLAB. The effects of the three kinds of structural controlare compared. Secondly, the dynamic rigidity matrix of soil is deduced with indirect boundaryelement method, and the formulas of structure in frequency domain are gained. Thestructure's reaction to earthquake is simulated based on these formulas, and theinfluence of SSI on the structure's dynamic reaction is analyzed. On the basis of theseworks, the formulas of three kinds of structural control considering SSI in frequencydomain are gained by substructure method via Fourier transformation. Afterwards, thestructure's earthquake reaction is simulated based on these formulas. The influencesof SSI on three kinds of structural control are analyzed. Finally, some conclusions are obtained as: First, the basic frequency of soil-structure system is reduced because of the existence of soil, which leads to the failureof ATMD control system and MTMD system that designed on the basis of systems'frequency. Second, after considering SSI effect, the effectiveness of MR dampercontrol system is enhanced due to the soil's damping of vibration. That is to say, itwill lead to economic waste without thinking SSI effect. Consequently, it is necessaryto take soil-structure dynamic interaction into account while designing structuralcontrol of structure founded on soft base.