Nondestructive testing procedure to evaluate the load-carrying capacity of concrete anchors

Concrete anchors are extensively used in the construction industry. Their applications range from erecting permanent objects such as sign poles, direction signs, lighting poles, and so on, to temporary support structures. Several destructive testing equipment types exist in the industry that can be used to evaluate the load-carrying capacity of concrete anchors. However, no nondestructive testing method has been proposed that can estimate their load-carrying capacity. This study develops a new relationship between the pull-out load-carrying capacity, P, of concrete anchors and Schmidt hammer rebound value, R. It was observed from experimentation that the load-carrying capacity of the concrete anchors depends on the embedment length, anchor diameter, concrete strength, and anchor alignment. The effect of anchor alignment was also observed during experimentation, and anchors with ill alignment of more than 5% can lead to lower load-carrying capacity. In addition, it is also possible to identify the ill-aligned concrete anchor and anchor bolt installed in poor quality concrete using the test results. A new type of anchor cage is also developed and presented in the research work that can be used to conduct the pull-out testing using the universal testing machine, eradicating the need for separate pull-out testing devices. The 8-, 10-, and 12-mm diameter concrete anchors were studied, keeping constant the embedment length and concrete strength. The pull-out load strength versus rebound value relationship for each diameter anchor is presented with a co-relationship of more than 90%.