Dynamic Response Investigation Of Bridge Structures Under The Impact Actions Of Debris In Flood

Natural disasters have occurred frequently recently, including floods and tsunami, which caused serious damage to existing roads, bridges, docks and other infrastructures or offshore structures. People always focus on how to reduce or avoid the impact of these natural disasters. Bridge plays the important role on transportation system and the number of medium and small span simply-supported bridges in the rural highway is up to the half of all bridges in China. Although the significant meaning is known to daily life and economic development of local areas, medium and small span simply-supported bridges is rarely be concentrated by researchers. Which should also be aware of when investigating engineering disasters by floods is that tremendous impact effect is not avoided owing to floater contained in water. It is rare research in the debris impact that due to the limitation of experimental conditions. However, more effective method is apparent in the finite element simulation of engineering problems with the development of computer technology.This study conduct exploration and analysis on the bridge impact combining with the relevant knowledge of floater, the main research contents of the study include:(1) The influence on bridge structure of floater and tsunami disasters were summarized. This paper expounds the existing collision theory and research method, compared the existing experience formula given in the specification and the key technology and main parameters setting used in finite element software modeling are explained.(2) Simply-supported T-type full bridge modeling is built by explicit dynamic analysis software ANSYS/LS-DYNA. Circular wood column and boats were selected as typical floater and pounding system modeling was established, then a variety of operating mode of the system dynamic response for numerical calculation and analysis were set up. First of all, from the point of view of energy, the process of changing was analyzed during pounding, energy conversion and transformation when pounding occur in bridges was conducted and studied pounding force time history curves under different working conditions. The relationship between peak pounding force, mass of floats and velocity was discussed in this paper.(3) The dynamic response process and characteristics of the bridge structure was analyzed by the calculation results of post-processing. This paper introduces the development and transformation of stress and change of displacement of various components subjected to impact effect. Investigate influence law between all factors by comparing the results of response of various conditions.