Variation Characteristics of Stress Wave Speed for Anchorage System Under Instantaneous Excitation

Dynamic nondestructive testing is widely used to evaluate the bolt anchorage quality in an anchorage system. The consolidating wave speed, stress wave speed for anchorage system under instantaneous excitation, is a required parameter for the evaluation. However, it is very difficult to determine the wave speed since it is affected by many factors. In order to solve the problem, this paper tries to establish the relationships between consolidation wave speed and wave speed in anchorage medium. This paper used dynamic nondestructive testing for measuring consolidation wave speed and wave speed in anchorage medium through experiment. The consolidation wave speed is measured by the grouted bolts in concrete fabricated by casting the bolts within one cubic concrete block with the dimensions of (600 mm × 600 mm × 2400 mm) around steel bars, and the wave speed in anchorage medium is measured by concrete specimens. The results indicate that the consolidation wave speed ranges from wave speed in concrete to that in free steel bar, the consolidation wave speed and wave speed in concrete vary in exponential law, and that they are mutually symmetric. This proposes the new idea that wave speed in anchorage medium can be used to calculate consolidation wave speed, and this can make the evaluation of anchorage quality much easier and more accurate because the testing of wave speed in anchorage medium is well developed and reliable and it can be determined by only testing on standard cubic specimens (150 mm × 150 mm × 150 mm).