抄録
Anchor bolts are used for installing structural members and facilities in concrete buildings. Under earthquakes or vibrations of equipment, anchor bolts are exposed to various kinds of force, especially shear force. The ultimate shear strength of anchor bolts has been investigated in many previous studies. However, there is little study on the stiffness that relates the shear force and the horizontal displacement. Therefore, it is difficult to evaluate the actual force of anchor bolts and the surrounding concrete in design and analysis.
This study aims to evaluate the mechanical behavior of an anchor bolt and the surrounding concrete under shear force. The beam on elastic foundation theory (BEFT) is applied to the anchor bolt and the surrounding concrete. A headed anchor bolt and a bonded anchor bolt are focused in this study. In the BEFT, the anchor bolt is modelled by elastic beams and the concrete and adhesives by elastic embedment springs. The accuracy of the BEFT is investigated by comparing to the results of an experimental test and previous studies.
The foundation constant of the elastic embedment springs representing the concrete and the adhesives is an important factor for the evaluation accuracy of BEFT. Some equations were proposed in previous studies. In this study, an evaluating method of the concrete foundation constant is proposed based on the concrete compressive fracture energy and the compression softening characteristics of concrete. The proposed equation gives the lower limit of the previous studies results.
A monotonic loading test was conducted on a headed anchor bolt. The test parameter is the edge distance of the anchor bolt along the loading direction. The shear load, displacement and curvature of the anchor bolts were measured. Concrete cone failure was observed in all specimens. The curvatures and the stiffness that relates the shear force and the horizontal displacement agreed with less than 50% error with the proposed method based on BEFT.
To apply BEFT to a bonded anchor bolt, an evaluating method of the adhesive is proposed. The proposed evaluating method shows good agreement with less than 50% error with the test results in the previous studies.
