A new technique for repairing reinforced concrete columns

Obaidat, Yasmeen Taleb; Ashteyat, Ahmed M.; Obaidat, Ala’ Taleb; Alfaris, Suhaib F.

doi:10.1016/j.jobe.2020.101256

Cited by 21 publications

(7 citation statements)

References 12 publications

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“…The improved load carrying capacity of beams retrofitted with CFRP using the technique of NSM is attributed to the increased width to depth ratio and less spacing between the NSM‐CFRP cords that results in enhanced axial strength of columns. [ 121 ] One reported problem is that when the CFRP laminates are applied only in the hogging region of continuous beams, it is unlikely that it enhances the load‐carrying capacity. However, the same is overcome by providing the laminates in both, hogging and sagging sections.…”

Section: Effect Of the Nsm‐cfrp Technique On Mechanical Properties Of...mentioning

confidence: 99%

A review on performance of near‐surface mounted‐carbon fiber‐reinforced polymer laminates bonded into slits

et al. 2022

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The near‐surface mounted (NSM) technique over the years has become the most popular retrofitting technique for obtaining enhanced strength and durability in reinforced concrete structural elements. It is mostly preferred for its easy application of composites in grooves cut on specimen concrete cover. The specimen surface is prepared with slits where polymer composite laminates are placed along with adhesives as filler to attain good bonding between laminates and the surface. The paper reviews the NSM carbon fiber reinforced polymer technique and its ascendancies over externally bonded composites retrofitting approach. Members strengthened with the NSM technique show enhanced shear strength, flexural capacity, and fatigue resistance. Motivated by the urge of gaining knowledge on various advantages of this emerging method, the paper reviews the load‐carrying capacity, failure modes, durability, and bonding behavior along with the enhancement ascertained in shear, flexure, and fatigue resistance by the NSM technique. In addition to offering guidance on the experimental and computational investigations on the overall behavior of the technique, the present review also intends to encourage further development in the near‐surface mounted carbon fiber polymer strengthening system of retrofit.

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Section: Effect Of the Nsm‐cfrp Technique On Mechanical Properties Of...mentioning

confidence: 99%

A review on performance of near‐surface mounted‐carbon fiber‐reinforced polymer laminates bonded into slits

et al. 2022

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“…Due to EB-FRP problems, using NSM-FRP shear strengthening became an attractive solution to overcome the limitations of the EB technique. Many researchers [36][37][38][39][40][41][42][43] investigated using NSM-FRP to increase RC structures' performance under compression, flexure, and shear. For instance, the flexural and shear capacity was enhanced by increasing the amount of FRP, orienting it in the suitable direction, and FRP properties.…”

Section: Introductionmentioning

confidence: 99%

Shear performance of reinforced concrete beams strengthened in shear using NSM bars and reinforced HSC layers

Abdo

Sharaky

Ahmed

2023

Structural Concrete

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The reinforced concrete (RC) beams could be upgraded in shear using steel and fiber‐reinforced polymer (FRP) having several shapes (bars, strips, or sheets). Using near‐surface mounted (NSM) Glass FRP (GFRP) bars is still limited compared to carbon FRP (CFRP) elements as shear reinforcement. Moreover, using reinforced high‐strength concrete layers (HSCL) as NSM shear strengthening for the RC beams is still limited. Herein, three RC beams internally reinforced in shear using different shear areas (without, 100 mm stirrups apart, and 200 mm stirrups apart) were experimentally tested as reference beams (CB). Other eight beams strengthened in shear using NSM HSCL, and bars were experimentally tested. Moreover, an extended finite element (FE) simulation was implemented through a verified FE model to study the effect of other NSM aspects on shear‐strengthened beam response. The results explained that, regardless of the internal stirrups area and external NSM characteristics, the shear‐strengthened beams showed higher load efficiency than the corresponding CB. The NSM upgraded shear beam had slightly higher load efficiency than the un‐strengthened beam having the same steel area as internally shear stirrups. Moreover, increasing the internal shear stirrups decreased the total efficiency of the NSM shear strengthening and the internal stirrups regardless of the NSM characteristics. Furthermore, the NSM HSCL was more efficient than the corresponding NSM bars in increasing the load capacity and stiffness of the shear‐strengthened beams. The reported analytical model predicted well the shear capacity of the tested beams.

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“…Currently, different methods are used in strengthening the concrete members. 29,30 The researcher primarily used steel plates bonded to the column via epoxy, 31 but this method led to severe corrosion issues. Handling long and heavy steel plates on the construction site proved difficult.…”

Section: Introductionmentioning

confidence: 99%

Rehabilitation of post‐heated rectangular reinforced concrete columns using different strengthening configuration

Abadel

2023

Structural Concrete

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It is common knowledge that increased temperatures have a negative impact on the axial load‐capacity and stiffness of reinforced concrete (RC) rectangular columns. This is something that is commonly acknowledged. For the purpose of restoring the axial capacity and stiffness of heat‐damaged RC columns, it is absolutely essential to carefully pick a suitable method for strengthening and repairing the columns. This research paper investigates the performance of various strengthening methods, such as the use of carbon fiber‐reinforced polymer (CFRP) jackets with near‐surface mounted (NSM) steel bars and a combination of welded wire mesh (WWM) and CFRP strengthening techniques, for the rehabilitation of RC rectangular columns that have been damaged due to exposure to high temperatures. Specifically, the paper focuses on the performance of these methods in relation to the rehabilitation of RC rectangular columns. There were three groups of tested RC rectangular columns: pre‐heated and unstrengthened, post‐heated and unstrengthened, and post‐heated and strengthened. Over a period of 3 h, 600°C was applied to the heated columns. Both a scheme utilizing a combination of unidirectional CFRP strips and NSM steel bars and another utilizing a combination of unidirectional CFRP strips and WWM were evaluated. Axial compression tests were performed on each column until failure occurred. The experimental test outcomes revealed that exposure to high elevated temperatures led to a decrease in the axial load‐carrying capacity of 38.6% and a decrease of 75.9% in initial stiffness, compared to unheated RC columns. Both strengthening schemes proved effective in restoring and surpassing the initial load‐carrying capacity of undamaged RC rectangular columns by an average of 35%. Notably, the combination of CFRP strips and WWM exhibited superior performance in restoring the initial stiffness of post‐heated RC rectangular columns, representing a novel finding. The strengthening scheme employing WWM and CFRP recovered 61.3% of the lost axial strength caused by high temperature, while the NSM/CFRP scheme restored 34.5% of the lost axial strength. In addition, the utilization of NSM in combination with CFRP strips as well as utilization of the WWM and CFRP systems leads to stiffness enhancement of 52.1% and 123.7%, respectively, when compared to post‐heated and unstrengthened RC columns. However, the study's findings have clearly shown that combination of WWM and CFRP strips is efficient in enhancing the strength of heated and unheated damage RC beams.

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A new technique for repairing reinforced concrete columns

Cited by 21 publications

References 12 publications

A review on performance of near‐surface mounted‐carbon fiber‐reinforced polymer laminates bonded into slits

A review on performance of near‐surface mounted‐carbon fiber‐reinforced polymer laminates bonded into slits

Shear performance of reinforced concrete beams strengthened in shear using NSM bars and reinforced HSC layers

Rehabilitation of post‐heated rectangular reinforced concrete columns using different strengthening configuration

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