Kota Chikura

Effect of Base-Plate Thickness on the Slip Behavior of High-Strength Bolted Frictional GFRP Joints

Gen Hayashi

In recent years, the application of glass fiber-reinforced polymer (GFRP) to bridge accessories has attracted increasing attention because of its light weight and corrosion resistance. For the connection of GFRP members, the practical application of high-strength bolted frictional joints is expected from the viewpoints of field applicability and performance assurance. However, the influence of factors such as plate thickness on the slip behavior has not yet been sufficiently clarified. Therefore, this study aims to clarify the effect of GFRP base-plate thickness on the slip behavior of high-strength bolted frictional joints.
In this study, GFRP plates were used as the base plates and steel plates were used as the splice plates. The target joint was a one-row, two-column high-strength bolted frictional joint using F10T-M12 bolts. A parametric finite element analysis and slip tests were conducted. In the numerical analysis, a model considering the symmetry of the joint was constructed, and the load–relative displacement relationship, initial stiffness, and bolt axial force were investigated to compare the influence of base-plate thickness. In addition, tensile loading tests were carried out using specimens with base-plate thicknesses of 5 mm and 14 mm. The presence or absence of continuous strand mat (CSM) was also considered as a parameter. During the tests, load, displacement, and bolt axial force were measured, and the effects of plate thickness and CSM on the slip coefficient and bolt axial force behavior were examined.
The analytical results showed that the relative displacement up to slip decreased as the base-plate thickness increased, whereas the initial stiffness increased. The experimental results showed that the slip coefficient increased with increasing base-plate thickness, and the value for the 14 mm specimens was 30% to 38% higher than that for the 5 mm specimens. Furthermore, even when CSM was introduced, the slip coefficient increased by 13% to 20%. These results indicate that base-plate thickness significantly affects the slip behavior of GFRP joints and plays an important role in the stiffness and slip resistance of high-strength bolted frictional joints.