Title: Tensile Capacity of Anchor Bolts in Uncracked Concrete: Influence of Member Thickness and Anchor’s Head Size

Author(s): R. Nilforoush, M. Nilsson, L. Elfgren, J. Ožbolt, J. Hofmann, and R. Eligehausen

Publication: Structural Journal

Volume: 114

Issue: 6

Appears on pages(s): 1519-1530

Keywords: anchor bolt; concrete cone breakout; head size; member thickness; pullout loading; size effect

DOI: 10.14359/51689503

Date: 11/1/2017

Abstract:
This study evaluated the influence of concrete member thickness and size of anchor head on the tensile capacity and performance of anchor bolts in concrete. Anchor bolts at various embedment depths (hef = 50 to 500 mm [1.97 to 19.69 in.]) in concrete members of various thicknesses (H = 1.5 to 5.0hef) were simulated. Three different sizes of anchor head (small, medium, and large) were considered at each anchor embedment depth. The numerical results were compared with predictions from several theoretical and empirical models, including current design models as well as some test results. The numerical results show that the concrete cone resistance increases with increasing thickness of concrete member and/or size of the anchor head. Simulations also indicate that current design models generally underestimate the tensile capacity of large anchors. Two modification factors are proposed to account for the influence of the member thickness and the size of anchor head. Predictions of anchorage capacity using the proposed modification factors have good correlation with the available test results found in the literature.