# Reliability Analysis of the Main Pier during the Construction Period of HLCR Bridges
###### Abstract
It is suitable to calculate the reliability when the distribution type of the random variable is difficult to determine but its first- and second-order moments are known. In 1951, the response surface method was born ([PERSON] et al., 2015). The basic idea of this is to use an explicit and easy-to-handle function to fit the complex and nonlinear implicit function in engineering structures. Then, on the premise of ensuring a certain calculation accuracy, the calculation amount is significantly reduced ([PERSON] et al., 2015). This method is mainly aimed at functions with a high degree of nonlinearity, large degree of fluctuation of the geometric surface of the limit state equation, low iterative accuracy, unstable iterative process and difficult convergence. [PERSON] (2016) proposed to apply the response surface method to the solution of reliability, and [PERSON] ([PERSON] and [PERSON], 2016) to engineering reliability. In 1974, [PERSON] and colleagues proposed the checkpoint method (also called the JC method) ([PERSON] et al., 2016). The JC method was developed with the first second-order moment theory. The JC method considers the actual distribution of random variables in the function and takes the checkpoint on the failure surface, which is consistent with the geometric meaning of the maximum failure probability of the structure, thereby improving the accuracy of the reliability calculation ([PERSON] and colleagues, 2016). Meanwhile, the Monte-Carlo (MC) method (referred to as the MC method) directly applies the principle of numerical statistics to a large number of random samples of the structure, analyzes the resulting values to determine whether they will lead to structural failure, and introduces the probability of failure or structural reliability of the structure based on a large number of sample values ([PERSON] and colleagues, 2016). The accuracy of the MC method calculation results depends only on the selection and number of samples. The MC method is widely used in engineering because it does not require the establishment of complex mathematical formulas. In recent years, domestic and foreign research scholars have focused their research on the MC method, on the selection of sampling methods and on how to reduce the number of simulations while reducing the calculation error. Based on this, they have proposed the significant sampling ([PERSON] and colleagues, 2016), stratified sampling ([PERSON] and colleagues, 2016), control variable ([PERSON] and colleagues, 2016) and pairwise variables methods ([PERSON] and colleagues, 2016). This study is based on the construction of the hanging cradles of a cross-river bridge project, and it takes \"the reliability of hanging baskets of an HLCR bridge\" as the research content. This research profoundly analyzes the current situation of domestic and foreign research, and it closely combines the construction method and process characteristics of the main girder part of a long-span, continuous, rigid-frame bridge. The JC method is used to establish a reliability analysis of the construction period and an evaluation model, which provide a technical basis for ensuring the construction safety and quality of the structure.