(1) In recent years, with the continuous increase of the state’s investment in infrastructure, the construction of highways and bridges has developed rapidly, which has brought great convenience to people’s lives. At the same time, with the increase of bridge service time, the reliability of bridges declines. In order to meet the requirements of sustainable development, it is necessary to accurately evaluate the reliability of bridges. However, most of the existing evaluation methods have single-weighting and one-sidedness. There are problems such as strong subjectivity and overly simple evaluation procedures. Therefore, it is urgent to establish a new scientific bridge reliability evaluation system. (2) Methods. In this paper, a bridge superstructure is taken as the research object, and the “Technical Condition Assessment Standard for Highway Bridges” (JTG/T H21-2011) is used as the criterion to establish a bridge reliability evaluation index system. The subjective and objective weights of the evaluation indicators are based on minimum discriminant information. Each evaluation indicator is combined and weighted; then, the closeness of each evaluation object to the positive ideal solution is determined according to Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). Finally, the reliability level of each evaluation object is determined. (3) Results. Reliability evaluation of the three-span superstructure of the bridge was carried out, and final reliability evaluation results of “Grade 2, Grade 2, Grade 2” were obtained, which are consistent with the actual working state of the bridge. (4) Conclusions. The evaluation results of this paper are consistent with the results obtained by the traditional AHP–Extenics method, but the evaluation model of this paper adopts combined weighting, which avoids the one-sidedness of the weighting of a single method—thus, the comprehensive weight obtained not only reflects the subjective intention of decision makers, but also reflects the objective properties of the data.

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 β 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.