Assessing The Capacity of Four Steel Hinges Extracted from Existing Bridges

Project summary:

Satisfactory performance and uninterrupted operation of steel bridges is contingent upon their structural integrity. Recent forensic investigations and finite element modeling on the inventory of steel bridges within the Minnesota Department of Transportation (MnDOT) jurisdiction has shown that girder hinge connection details are susceptible to corrosion and stress concentrations that can lead to reduced capacities. These issues have raised concerns among stakeholders and practitioners regarding the adequacy of steel hinges currently in service. Recently, MnDOT replaced four steel hinges in a local bridge that were deemed to have insufficient capacities based on numerical analyses. The extracted hinges were salvaged with the goal of testing the hinges to investigate their actual capacities and the accuracy of the results of the numerical models. The main objectives of this project are summarized below: 1. Determining the load capacity of two of the extracted steel hinges, through large-scale monotonic testing. 2. Determining the high-cycle fatigue capacity for two of the extracted hinges, through large-scale cyclic fatigue testing. 3. Development of finite element models and their verification with experimental results. 4. Performance assessment of several other steel hinge configurations within the MnDOT inventory using finite element analysis. 5. Parametric study with the aim to propose improved detailing practices for repairing and strengthening of other existing bridge steel hinges. 6. Assessing the effectiveness of previously proposed simplified models for estimating the capacity of steel hinges in bridge girders and propose improved methodologies as necessary.