Mechanics Behavior Analysis Of Butterfly Arch Continuous Girder With Wide Angle V-shaped Pier Bridge

Beam bridge is a structural system with a long history. On the basis of static system, it can be classified into three types:simply supported beam, cantilever beam and continuous beam bridge. In recent years, with the development of building materials, design theory and construction technology, the innovation of bridge structures which is based on traditional bridge theory is endless. V-shaped pier of butterfly arch continuous girder bridge is just one of the new structures created under this background. Besides, V-shaped pier enriched the art forms of bridge. At the same time, it highlights the advantages of increasing the overall stiffness, reducing the span and improving the mechanical properties of the main beam. Ⅴ-shaped butterfly arch has lateral angle of the bridge, which, watched from a distance, is like a butterfly that spreads its wings to fly. The type of bridge has novel appearance, space curves and strength feeling and features of artistic design as well as technical innovation. But the structure of Ⅴ-shaped butterfly arch is complex; the design and construction are relatively difficult. Therefore, it has important practical value to analyze the stress characteristics of the structure accurately, master the forms of structure damage, carry out the study of the ultimate bearing capacity and obtain its secure reserve capacity under specified stress conditions. And it can provide reliable reference and instructions for the similar bridges’ design, construction and monitoring.This paper refers to the Heihe Island butterfly arch-continuous beam bridge project in Heihe City, Heilongjiang Province. Its Ⅴ-shaped pier has characteristics of large angle and bidirectional Ⅴ-shaped, which is the first case in China. By some research methods such as theoretical analysis, numerical simulation, construction site monitoring and neural network, we study the regularity of large angle Ⅴ-shaped pier butterfly arch-continuous beam bridge’s sensitivity to different structural parameters and the reasonable buried position of strain sensors, determine the biggest stage of the risk of structural failure. The main work includes the theoretical analysis, burying the strain sensors, data testing and analysis, numerical simulation of the structure, as well as concluding the regularity of multi-parameter sensitivity. The main research contents and results are as follows:(1) By combining the numerical simulation analysis with testing at the construction site, we analyze the large angle V-shaped pier butterfly arch-continuous beam bridge’s sensitivity to different parameters. And by combining the artificial neural network technology with the parameter sensitivity analysis, we identify the impact on the state of the system parameters, and analyze the impact of parameter changes on the state of the system, after which we can identify the parameters that have impact on the system state according to a specific system and a given reference state. Parameters sensitivity at the construction and operation stage is summarized to provide theoretical support for similar bridge design and construction.(2) Set up the static state analysis finite element of Heihe Island butterfly arch-continuous beam bridge and carry out analysis and researches. Select the position which is unfavorable for structure stress, the position where the stress is not clear and the position focused on to bury the sensors. Then preliminary determine the layout form of the sensors and put forward optimization scheme of the layout form of the sensors that can offer comprehensive and accurate force information of the structure according to the correspondence relationship of the testing data at the construction site and model analysis results, which improving the efficiency and accuracy of similar bridge construction monitoring to ensure the safety of bridge construction.(3) Dynamic property research on V-shaped butterfly arch-continuous beam bridge. By the basic means and modeling principle of dynamic analysis, Midas/civil2010seismic analysis model of V-shaped butterfly arch-continuous beam bridge is set up to analyze the self-vibration characteristics of the bridge. Heihe Island Bridge models of both considering and not considering the pile-soil effect are established and analysis on the two models’self-vibration characteristics in the first10phases is carried out. The influence on pile-soil effects on vibration characteristics of the structure is also discussed. Response spectrum method and time history method are used to discuss seismic analysis of the bridge; it’s clearly showed that taking pile-soil effects into consideration in the dynamic analysis is rather necessary. Methods above provide reference material for similar bridges in structure optimization.(4) Set up ANSYS space finite element model of V-shaped structure. By contrastive analysis on local stress theoretical results and vibrating wire transducer measured data, stress distribution of V-shaped structure in different phases can be obtained. MATLAB, a data analysis program, is used to carry out regression analysis on testing data. Combined with Artificial Neural Network, both the influence on the structural damage and the failure of internal and external risk factors can be forecast. Moreover, the venture analysis on structure failure can be carried out. In this paper, we propose a theory based on AHP.Gray-Monte Carlo-FEM-neural network synthesis methods for risk analysis, which can solve the problem that previous risk decision was relied on experience and qualitative analysis of decision makers. As a consequence, that makes it more reliable and operable. On the basis of the risk factors that has an impact on bridge construction phase, preventive measures for construction phase risk factors of Heihe Island butterfly arch continuous beam bridge are put forward.This article provides not only practical research methods and achievement to understand large angle V-shaped butterfly arch-continuous beam bridge deep but important references for building design, construction, monitoring and the establishment of risk evaluation system as well.