This book follows: Ground Anchors: Tension Force Vibratory Analysis JJ Rincent Springer Sept 2024. This new book is a summary of experience gained from the analysis of over 24 000 test curves obtained from 3000 ground anchors analysis. It provides practical feedback on the complexity of non-destructive testing. The test equipment, the rules to obtain interpretable acquisition results. The examples come from trials carried out in Brazil over the last 5 years and finally, the test methodology adopted for this experiment. These tests are generally carried out on ground anchors using strands as reinforcement or rebars several decades old. Information on their length and initial tension force is often non-existent after 40 years. That's why these vibration analysis tests provide the answers and information needed for stability and maintenance diagnostics. The examples chosen concern ground anchors equipped with bars, strands and also for nails, passive ground anchors and micro piles. Tests on prestressed dowels are described, and a test on a reinforcing bar linked to the construction of an early 16th century castle will be carried out. As a reminder that these tests results lead to define the total length of the tie bar, the free length, the diameter of the tie bar, i.e. the reinforcement with its cement grout, and finally the tension force at the time of testing. These data are essential for assessing the stability of retaining walls stabilised by tie rods. It should be stated that static tests, which are difficult to carry out at height, provide no information on lengths and run the risk of breaking old tie rods. All the tests carried out are used to construct the test method that can be adopted, taking into account the feedback acquired from thousands of static tests. For retaining structures and tie rods in particular, access to the head of the tie rods must be preserved in order to: - carry out inspection tests - re-tension the tie rods, if necessary - while protecting them from corrosion. Meeting these conditions means implementing sustainable maintenance of the structures. This test method is a diagnostic tool for ground anchors used by managers of retaining structures to design maintenance projects. The final aim is to increase the durability of the retaining structures. The tests proposed and explained using numerous examples and finally to propose a methodology for carrying out vibration analysis tests on ground anchors, as well as a framework for their interpretation.
