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

Abstract

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.

Impact and notched strength of multiaxially reinforced out of die UV cured pultruded profiles

“…It has been proved that adding multiaxial patches on the joining zone can considerably enhance the load bearing capacity of the pultruded profile joints. [20][21][22][23][24] This improvement is related to a shift in the failure mode from a sudden shear-out to a progressive bearing failure. However, this approach involves using additional material and supplementary manufacturing operations.…”

“…We conducted two mechanical tests particularly challenging for conventional pultruded profiles to validate the multiaxially reinforced profile: out-of-plane multiaxial drop weight low-velocity impact tests and open hole tensile (OHT) tests in the two principal in-plane directions. The performance of a pultruded profile reinforced with stitched continuous strand mat (CSM) and roving was used as a reference since this reinforcement configuration has been extensively studied in the published works related to low-velocity impacts [16][17][18][19] and OHT [20][21][22][23][24] in pultruded composites.…”

“…Since in pultruded composites reinforcement is primarily aligned longitudinally, the thickness around bolted or riveted connections has to be oversized to accommodate the applied loads. It has been proved that adding multiaxial patches on the joining zone can considerably enhance the load bearing capacity of the pultruded profile joints 20–24 . This improvement is related to a shift in the failure mode from a sudden shear‐out to a progressive bearing failure.…”

New Anchorage Technique for GFRP Flexural Strengthening of Concrete Beams Using Bolts-End Anchoring System

“…The application of carbon (CFRP), aramid (AFRP), and glass (GFRP) for strengthening beams has been wildly investigated by various researchers. However, the testing data on the flexural response of beams reinforced with bolt-end anchoring glass fiber polymer composites (BEGFPC) is limited, Tran et al (2022). More testing data on (BEGFPC) strengthening is desired to supplement the current understanding for more reliable and convincing results.…”

Bearing Properties of CFRP Composite Laminates Containing Spread-Tow Thin-Plies

“…The primary and secondary load-bearing aircraft structures have several composite bolted joints [ 8 ]. However, these joints are commonly the weakest area in a composite structure and this kind of material lacks the ability to redistribute local high stresses.…”