Mechanical Analysis And Reliability Calculation For Box Culvert With Low Reinforcement Ratio Under Earthquake Action

As a natural disaster, earthquake often destroys ground and underground building structures, which lead to enormous casualties and property losses. Therefore, the study of seismic reliability for structures is essential for the disaster prevention and mitigation. With the accelerate of the pace of urbanization in our country, there are more and more underground structures and lifeline facilities, such as the metros, underground shopping malls, tunnels across river and drainage culverts. The seismic reliability of underground structures is increasingly concerned by the people. The invisibility and complexity of underground structures, the uncertainty of environmental parameters, the complex laws of earthquake nature, the transient episodic, and the strong destructive make the study of seismic reliability of underground structures become more complex and important.The mechanical analysis and seismic reliability of box culvert with low reinforcement ratio were studied based on the related literature and research results of domestic and foreign colleagues. The contents and main results of study are as follows:(1) Based on the results of non-destructive testing for the distribution of steel bars in the box culvert structure, the distribution law for steel bars was counted up used the mathematical method, and the ANSYS mechanical model for the box culvert was established by making the programs based on this distribution law.(2) The stress characteristics and the variance law of deformation for the structural members of culvert box with the seismic time and load were found through the dynamic analysis of the box culvert with low reinforcement ratio under earthquake.(3) The limit state equation for the structural members of culvert box was deduced by using reliability theory based on analyzing the failure criterion of underground structures under earthquake and combining with the features of box culvert structure.(4) A method for calculating the reliability of underground structures was established by developing an artificial neural network program and a Monte-Carlo program based on the ANSYS software, the artificial neural network (ANN) theory and the Monte-Carlo (MC) method, and applied to calculate the seismic reliability of a culvert box with low reinforcement ratio successfully.