Fatigue life updating of embedded miter gate anchorages of navigation locks using full-scale laboratory testing

Abstract

Locks and dams facilitate the transportation of billions of dollars in goods through inland waterways annually. Miter gates are lock components that are supported by steel anchorage frames embedded in the concrete lock wall. In the US, many of these anchorages have been subjected to over 80 years of cyclic loads. The typical analysis approach for anchorages treats the steel frame as a freestanding truss, ignoring the embedding concrete. This approach predicts that some anchorages may imminently fail in fatigue. Thus, there is a push to excavate and replace these anchorages at a cost of nearly $10 million USD per site. Previous numerical modelling of an embedded miter gate anchorage, considering the effects of concrete, shows that the stress in most of the anchorage is below the endurance limit of steel. To verify these modelling results, a full-scale laboratory test is performed wherein a representative anchorage is instrumented and loaded under typical gate loads. The testing is performed in three phases: the first phase represents the freestanding truss; the second and third phases represent the fully embedded anchorage in two typical orientations. Results of the test support the numerical modelling results, suggesting that planned anchorage replacements are not required.