Research On High Formwork System Of Proscenium Beam Considering Time-varying Strength Of Construction Structure

With the fast economic growth in China, the demand for high formwork system is increasing lastly and the application of it is widely used in construction. From 20 centuries since 90s are prime, the development of frame system experienced huge change and transformation. China has established its own scaffold industry by using foreign development experience. The main question for high formwork system is the accidents of collapse, the analysis of accidents indicates that collapse is basically due to design calculation and erect scaffold. The main two reasons are the lag of computing method and the irrationality of load. The present design calculation just considered the stability of single frame pole and step, but didn't propose a more reasonable calculation of requirements for high formwork system. It doesn't consider the interaction of each pole and the influence of the time-varying strength of construction structures.Through an analysis of the time-varying structure theory of concrete, the physical properties of structure during construction process is a typical slow speed time-varying structure problem. In the research time freezing method can be used to dispose it. Pre-poured concrete structure may cooperate with high formwork system to bear the weight of new part. The proscenium beam of Anhui radio and television broadcasting center is taken as research background, the design of high formwork system considered time-varying strength of construction structure. Through the analysis of the cooperative functioning model by experts home and abroad, research in this paper establishes rational finite element model and verifies the safety of it. By monitoring the deflection of the beam when dismantle the frame system, the safety of the beam is guaranteed. By monitoring the stress of the beam from embedded static strain sensors through all the entire process of construction, the reliability of finite element model is verified. Research in this paper establishes two kind of finite element model, one considers the time-varying structure theory of concrete, and the other does not. It analyses the characteristics and laws of the axial force of the high formwork system and the influence of the horizontal pole and the shear pole, and compares the difference of the two model, it shows the better economical efficiency when design considering time-varying strength of construction structure. At last, research in this thesis proposes some suggestions for further improvement of the design, and provides scientific basis for the economy and safety of the high formwork system design.