Non-destructive Testing Method to Evaluate the Load Carrying Capacity of Nails

Abstract

ABSTRACT. Anchor nails are commonly used in the construction industry. They are categorized as epoxy and friction nails. Epoxy nails are stronger but they require skilled labor for installation and are expensive. For general applications mechanically installed friction nails are preferred. Till date there exists no non-destructive testing method to estimate the load carrying capacity of these nails. The study presents a newly developed non-destructive testing method to estimate load carrying capacity by relating the rebound value of Schmidt hammer to the pull-out load carrying capacity of nail. Factors affecting the rebound hammer such as hardness of the nail head, embedment length, diameter, concrete strength, the damage caused inside the concrete, nail alignment and the interfacial frictional bond are also studied. A relationship between pull-out strength and rebound value Rfor 50 and 38 mm diameter nails with embedment lengths of 10 and 20 mm is presented.