Key points are not available for this paper at this time.
AASHTO specifies a one-bolt-diameter cutoff for standoff distance to consider bending stresses in anchor bolts. When evaluating the strength of anchor bolts in accordance with these specifications, many cantilever-type support structures with a standoff distance of slightly more than one bolt diameter were determined to be structurally insufficient. In this paper, a comprehensive study on bending stresses of anchor bolts for cantilever-type structural supports was performed. Two finite-element models were developed, one using solid elements to model individual anchor bolts and the other using beam/plate elements to model an entire group of anchor bolts with a base plate. Parametric studies were carried out to investigate the effects of number of bolts, base plate thickness, and standoff distance on bending stresses. Based on ultimate strength theory, strength limit states for individual anchor bolts and entire groups of anchor bolts were derived to include the influence of local bending stresses. As an illustrative example, anchor bolts of an existing cantilever sign structure were evaluated in accordance with AASHTO and AISC. This example demonstrates advantages of the load and resistance factor design method over the allowable stress design (ASD) method.
Chunhua Roger Liu (Wed,) studied this question.