PULL-OUT CAPACITY OF EXPANSION ANCHOR BOLT AS INFLUENCED BY CORROSION

Abstract

The expansion stud anchor bolt is one of the most used construction materials due to its flexibility in installation and connecting structural members. However, due to the geographic condition of the Philippines, consisting of 7,107 islands with 36,289 kilometers of coastline, water particulates from seawater increased the corrosion process of any steel material, including expansion stud anchor bolts. The objective of the study is to use neural network modeling to determine the effect of corrosion on the pull-out capacity of an expansion stud anchor bolt as influenced by corrosion considering different parameters such as Half-cell Potential, Gravimetric Test Result, compressive strength of concrete, and presence of waterproofing. The Impressed Voltage Technique (IVT) accelerated the corrosion process on 35 pieces of 250 mm x 250 mm x 150 mm concrete samples with and without waterproofing admixture, installed with uncorroded expansion stud anchor bolts. The behavior of the pull-out capacity, including the order of importance of the input parameters, was analyzed using neural network modeling. Among the parameters considered, the number of days subjected to IVT, which accelerated the corrosion process, is the primary and most significant variable in influencing the pull-out capacity of an anchor bolt.