Collapse-Resistant Measures For Single-layer Reticulated Shells Under Strong Earthquakes

The single-layer reticulated shell structure has the advantages of attractive design, reasonable stressing, simple production and convenient installment, which makes it widely used in public buildings. If it collapsed in earthquakes, there would be a great many of casualties and economic losses. This paper takes the single-layer cylinder shell structure as the main research object, focuses on the seismic control of viscous dampers in single-layer shell structure, puts forward and verifies the optimal location principle of viscous dampers, studies on the major parameters and regularity which influence the vibration reducing effects of single-layer shell, and discusses on the collapse-resistant measures for strengthening sections. The main research is as followings:(1)Taking the single-layer reticulated shell structure as the object of study, this paper illustrates the principle and analytical methods of seismic control of viscous dampers.(2) In consideration of the current researching situation and existing problems of placing viscous damper in the single-layer structure, an optimal location principle for viscous damper based on the energy equation is proposed. It points out that in earthquakes, the optimal setting zones are those with bigger sum of the absolute value of relative displacement of nodal point on members in uncontrolled single-layer shell structure in all the time incremental steps. According to this optimal location principle of viscous damper, this paper compares the optimal and other setting methods in single-layer cylinder shell, and testifies the validity of this principle.(3)Considering different setting manners, numbers, damping coefficients, linear and nonlinear damper, this paper studies on the main parameters and regularity which influence the vibration-reducing effects of single-layer reticulated shell.(4)This paper discusses the collapse-resistant measures for strengthening sections, compares the profits raised by the ultimate bearing capacity and the increased losses of steel usage, and analyzes the impacts on the ultimate bearing capacity of the different methods.