# Reliability Analysis of the Main Pier during the Construction Period of HLCR Bridges
###### Abstract  
In the process of cradle construction for high-pier, long-span, continuous, rigid-frame (HLCR) bridges, the strength failure and instability damage of the main pier will directly affect the bridge construction safety. Therefore, it is necessary to study the reliability of the main pier during the construction of HLCR bridges. This paper starts from the factors that easily affect the stability of the main pier during HLCR bridge cradle construction, establishes the resistance and load probability model of the main pier during the maximum cantilever stage and the maximum unbalanced load of the continuous, rigid-frame bridge's hanging cradles, fully considers the influence of random factors on the reliability of the pier, and calculates and analyzes the reliability index \(\beta\) through calculation examples. The results show that the changes of various random factors during the construction process have different degrees of influence on the reliability of the bridge pier. Our work provides a basis for the safe control of hanging cradles in the construction of HLCR bridges. cradle construction; reliability; pier; probability model; JC method 20221  
structures during the construction period, and as a result, the frequent occurrence of bridge construction quality errors and safety accidents, with serious economic losses and huge social impacts. To date, there has been some research on the reliability of bridge structures during the construction period at home and abroad. There are roughly three evolutionary stages in the research: the first stage is mainly based on the subjective judgment of experts on whether the structure will collapse, break or other accidents will occur based on their experience and after observing the structure. The second stage is that people judge the reliability of the structure based on the theory of the safety factor. In the third stage, reliability is used to express the probability that the structure will achieve the expected goal. The reliability theory is based on the probability theory and evaluates and optimizes the safety, quality and reliability of the structure through mathematical calculation, taking into account the uncertainty and randomness of all important parameters that affect the safety and reliability of the structure during the design and construction process. Internationally, the boom of structural reliability theory development was in the middle of the 20 th century, in which the classical reliability theory was born, became accepted and started to be used by the engineering community after in-depth research. In China, the reliability theory developed rapidly in the decade from 1984 to 1994. Dalian University of Technology and Tsinghua University have done a lot of work on reliability-based structural durability research [4]. Analysis of the factors affecting the quality and safety of bridges at each stage of construction, how to express these factors and how to quantify them has become one of the main tasks of bridge reliability research during the construction period. Since HLCR bridges are mostly constructed in mountainous areas, and the cantilever hanging cradle method is most used to construct the main girders of a continuous rigid bridge, the overall instability of the bridge will reach a maximum when the construction reaches the maximum cantilever state, which seriously affects the safety of the bridge during the construction period. In recent years, research on the reliability of the overturning resistance of the maximum cantilever construction stage of a continuous rigid bridge has been increasing. [PERSON] [5] found that when using the balanced cantilever method to build concrete bridges, it is easy to lose the overall stability due to structural overturning. From the perspective of safety, the magnitude of cantilever construction force is studied to achieve a similar level of reliability across the span of these bridges. [PERSON] [6] analyzed the safety problems of temporary works during construction.