Performance of FRP strengthened full-scale simply-supported circular hollow steel members under monotonic and large-displacement cyclic loading

Abstract

Steel structures are becoming more common in engineering construction as steel possesses excellent ductility, but steel members are often vulnerable to buckling, especially under seismic or cyclic loading. Hollow structural sections (HSS) often buckle locally under loading due to their thin steel walls and the need for rehabilitation and strengthening is increasing. In the present study, circular hollow section (CHS) steel members have been strengthened with both carbon fibre reinforced polymer (CFRP) and glass fibre reinforced polymer (GFRP). Their structural performance, along with that of their bare counterparts, is investigated subjected to monotonic and quasi-static large-displacement cyclic loading experimentally. The types of FRP reinforcement (CFRP and GFRP) and the loading condition (monotonic and cyclic) are chosen as two main parameters in the test program. Results reveal the significant structural improvements of the strengthened CHS members under monotonic and cyclic loading. The ultimate moment capacities of the beams under monotonic and cyclic loading are enhanced by 51.0% and 35.4% respectively with CRFP strengthening and 43.3% and 31.5% respectively with GFRP strengthening compared to the bare beam. In addition, all the FRP strengthened specimens achieved higher moment capacities, rotational capacities, stiffness, energy dissipation capacities and ductility in comparison to their bare counterparts. Moreover, there is a good agreement found between the experimental and theoretically predicted ultimate moment capacities of the bare and strengthened CHSs with a mean ratio of 1.04 and a COV of 0.05.

Structural behaviour of CFRP strengthened beam-column connections under monotonic and cyclic loading

“…The CFRP fibres are applied with the first two layers running longitudinally with the beam to utilize the high tensile property of CFRP and the third layer wrapped in the lateral direction on the beam which will provide better confinement of the first two layers. This style of orientation has been chosen as it showed good performance in a previous study [22,45]. To obtain adequate confinement of the overlapped CFRP fibres coming from the beam, the first and third CFRP fibres on the column are applied horizontally along the column surfaces while the second layer is applied vertically along the column surface to best utilise the benefits of CFRP.…”

Experimental Study and Discrete Analysis of Compressive Properties of Glass Fiber-Reinforced Polymer (GFRP) Bars

“…Reinforced concrete (RC) structures are severely affected by corrosive environments, leading to the corrosion of steel bars and reducing the strength of components. Compared to iron and steel materials, fiber-reinforced polymer (FRP) has the advantages of being lightweight [ 1 ], high strength [ 2 , 3 ], insulation [ 4 , 5 ] and high corrosion resistance [ 6 , 7 , 8 ] which dramatically increases the use of FRP bars including GFRP bar in civil structures, specifically in adverse and corrosive environment to maintain high safety and durability [ 9 ]. As an anisotropic material, the strength of GFRP is affected by many factors, such as fiber content, matrix type and manufacturing process.…”

Ductility of Precast Concrete Column Beams Using Dowels

“…In this research, the connection used is a dowel, which is used as a connecting material between structural components. Therefore, planning of building structural elements really needs to pay attention to strength and ductility (Kang & Tan, 2015), (Breccolotti et al, 2021), (Tafsirojjaman et al, 2021), as well as consideration for evaluating the performance of the dowel connection system (Ghayeb et al, 2020). Precast concrete joints use a variety of configurations, including: (a) Angle joints and steel bars with or without reinforcement; b) joints using steel plates and bars; (c) Use of cast-in-place (CIS) concrete for joints; (d) especially bolted joints (Ying Zhou et al, 2022).…”