Multiple crack extension model of steel anchor bolts subjected to impact loading

Steel anchor bolts embedded in concrete are designed based on standards that assume to have a uniform stress along with single crack failure. However, experimental evidence has shown that the steel anchor bolt failure is governed by a combination of failure patterns such as cone and splitting type failure, hence the assumptions of uniform stress and single crack failure are not valid. In this regards the presented manuscript details an analytical model related to the anchor bolt failure subjected to impact loading. Impact loading is such that is introduced using a Schmidt Hammer in order to judge the pull-out strength steel bolts. The presented analytical model takes into consideration multiple crack extension scenarios, such as interfacial cracking initiated from top and bottom of steel bolt along with the case of simultaneous crack extension. The presented model is further capable of taking into consideration a variety of anchor types such as straight, hooked and bent type of anchors. The theoretical and experimental results comparison proved that the presented analytical model was capable of predicting the peak load capacity and could also simulate the pre and post peak failure mechanism. The proposed model can be employed by professionals to judge the deformational response of various types of steel anchor bolts.