Horizontal Dynamic Loading And Lateral Stiffness Of Temporary Stands

Temporary stand has the advantages of short building cycle and low cost. Its recycling ratio is close to one hundred percent, thus is environmental friendly and can save lots of energy. Temporary stand started early and has developed fast and applied widely in developed countries or areas such as Europe. However, the application of this kind of construction in our country has much shorter history and the research in this field is relatively late. So far no specifications in the field of architecture have been made for this type of construction. Temporary stand is characterized as "large, light and soft" which cause the structural natural frequencies become lower and the loads of crowds on the stands will induce strong vibration easily, causing severe issues of safety and comfort. In this paper, the model of horizontal load induced by human body has been establishment and applied on the temporary stands. The comfort level is evaluated through the horizontal dynamic response and the lateral stiffness of stands were studied in order to improve the safety and comfort of the temporary stands. The main research contents of this thesis are as follows:1、Based on the horizontal vibration test on human-structure system, the model of jumping and swing human body has been established. The experimental results show that, the displacement response during body jumping and swing shows obvious changing tendency and periodicity; jumping can cause larger magnitude of horizontal displacement and acceleration than swing, while swing has wider frequencies.2、The finite element model was constructed and its dynamic characteristics was analyze. Based on the theoretical horizontal load model of jumping and swing of human body, the finite element software was used to simulate the dynamic response of temporary stands under the crowd loads and to evaluate the level of comfort of such stand structures.3、Through theoretical and numerical analysis, the improvement of lateral stiffness of the temporary stands consist of bar-like structures was studied and this helps to improve the security and workability of the stands effectively. Through the numerical analysis of different support distribution, the concept of direct force transmission was verified and the effective way of support distribution was determined which could help to improve the lateral stiffness and to save the cost.In general, the interaction between human beings and structures is complex, and the model of crowd-induced loads for temporary stand can only be defined based on the practical engineering measurements and statistic data. To improve the safety and workability require not only higher lateral stiffness, it is also affected by many other factors that are sometime coupling with each other. All these problems need in-depth and meticulous future research.