Multi-Bolted Connection for Pultruded Glass Fiber Reinforced Polymer’s Structure: A Study on Strengthening by Multiaxial Glass Fiber Sheets

Pultruded Glass Fiber Reinforced Polymers (PGFRPs) are becoming a new mainstream in civil construction because of their advantageous properties. One of two main elements, glass fibers, have been constructed by unidirectional glass roving in applicate progress. PGFRPs do not have high shear strength, which is determined by another element is the matrix. In the future, the demand for enhanced serviceability of existing PGFRP structures could be seen as unavoidable. Therefore, multi-bolted connection being the most typical type of connecting member, strengthening the connection performance of PGFRPs through connection is necessary. Previous researchers have studied several methods for improving connection capacity, including pasting glass fiber sheets (GFS). However, experimental research is lacking for multi-bolted connection. This study investigated several strategies of specimens, including the quantity of bolts (two bolts, four bolts, and five bolts); the end distance/diameter ratio (e = 2d; e = 3d) under tensile load; and three types of glass fiber sheets (GFS) (0°/90°, ±45° and chopped strand mat (CSM)). The experiment’s results showed the strengthening effects and the failure mode on the specimens. These findings could address the gap in knowledge that needs to be resolved with respect to PGFRPs’ composite design, through evaluation and discussion of their behavior.