Modelling impact resistance of polymer-laminated steelwork

2019

J. Struct. Eng.

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Use of carbon fibre reinforced polymer (CFRP) strengthening of structural elements has been gaining increased traction over the past few years. Although some research has been carried out on the behaviour of CFRP strengthened steelwork under static and fatigue loads, no single study exists which experimentally captures the response of CFRP strengthened steel beams under impact load. In the present study, a series of tests was conducted to gain insight into the effect of impact load on such beams. The parameters examined in the experiments were namely the thickness and length of the CFRP layers. The impact test was performed by dropping a 91 kg impactor with a velocity of 4.43 m/sec. A finite element analysis (FEA) model was developed in which the bond between CFRP and steel, strain rate effects for steel, and failure of both CFRP and adhesive material were included. Comparing the test data with corresponding FE results confirmed a high level of accuracy of the predicted results. A series of detailed analyses on the impact behaviour of CFRP strengthened steel beams was performed using the validated FE model to provide further insight.

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Investigation of CFRP-Strengthened Steel Beams under Impact Load

2019

J. Struct. Eng.

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“…To date, a relatively small number of studies have been conducted on the behaviour of CFRP strengthened metallic structures under impact loading [9][10][11][12][13][14]. Among these limited studies, Al-Zubaidy et al focused on the bond characteristic between CFRP fabric and steel plate under impact loading by testing a series of double strap joints under different strain rates.…”

Section: Introductionmentioning

confidence: 99%

“…While in the latter study where the model accounted for potential de-bonding, the reduction in the transverse displacement was between 44% and 17% depending on CFRP configuration, preloading level and boundary conditions etc. Further to this, Kadhim et al [14] examined the behaviour of CFRP strengthened steel I' section beams under impact loads using ANSYS.…”

Section: Introductionmentioning

confidence: 99%

Experimental study of CFRP strengthened steel columns subject to lateral impact loads

2018

Composite Structures

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In both building and civil engineering structures, the occurrence of impact loading to column elements can be a significant issue, particularly in regard to disproportionate collapse. For existing structures vulnerable to impacts, the development of appropriate strengthening techniques is key to extending service life and improving robustness. In the case of structural steelwork, composites such as carbon fibre reinforced polymer (CFRP) offer a promising means of retrofitting and improving performance under impact. Towards this, the present study experimentally investigated a total of 12 square hollow section (SHS) columns under impact loads. The test series included both unstrengthened and CFRP strengthened samples with different fibre orientations with a view to finding the optimum CFRP configuration. As a means of simulating lateral impact on axially loaded elements, a purpose-built test rig was manufactured to apply a compressive preload to the samples prior to impact. Different preloading levels were applied to the samples before they were impacted transversely. The results show that the strengthening effectiveness increased with higher preloading level. The average reduction in the transverse displacement for the strengthened columns tested under 70% preloading level was around 32% compared to the unstrengthened column while this value was about 22% for the columns tested without compressive preload.

“…Correspondingly, the response of FRP strengthened steel structures under quasi-static loading rates has been widely covered [1][2][3]. To date, structural behaviour of steel members strengthened with FRP under impact loading is limited to a very few exploratory studies [4,5]. Thus, much uncertainty still exists surrounding the differences between the structural behaviour of these kinds of strengthened members under impact.…”

Section: Introductionmentioning

confidence: 99%

Loading rate effects on CFRP strengthened steel square hollow sections under lateral impact

2018

Engineering Structures

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Application of fibre reinforced polymer (FRP) composites has steadily gained popularity in rehabilitation of steelwork over the last decade or so. This popularity is based on the inherent advantages of FRP and the considerable amount of research conducted on the response of FRP strengthened steelwork members under static loads. However, over the course of their service life, steel structures can be subjected to impact loads induced by a variety of sources. This necessitates the requirement for a comprehensive study that can shed light on the behaviour of FRP strengthened steelwork under various loading rates. This paper discusses the experimental results of carbon fibre reinforced polymer (CFRP) strengthened square hollow sections (SHS) under different loading rates. The experiments comprised a series of SHS columns tested under two loading rates: quasi-static (0.05 mm/sec) and impact (4.43 m/sec). Some of these columns were strengthened with different CFRP configurations comprising fibres oriented in the longitudinal direction, transverse direction and in both directions. The effect of coexisting axial compression applied prior and during the application of the transverse load (impact or quasi-static) was also examined. The axial load was introduced in the experimental program to simulate the normal service load that exists on columns in multi-storey frame buildings. Generally, it was found that the effectiveness of CFRP strengthening was increased at a higher loading rate to different degrees depending on the CFRP configuration.