Cyclic Performance of RC Columns with Inadequate Lap Splices Strengthened with CFRP Jackets

Kalogeropoulos, George; Tsonos, Alexander G.

doi:10.3390/fib8060039

Cited by 13 publications

(16 citation statements)

References 18 publications

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“…The first specimen was non-retrofitted, while the rest of the specimens were strengthened with either the developed 3D-TRM panels or conventional FRP sheets. The conventional wrapping method for FRP sheets is used and its retrofitting procedure can be found elsewhere [24][25][26], while the retrofitting method using Materials 2022, 15, 592 6 of 17 3D-TRM panels is described in Section 3.2. The selected retrofitting types and properties of concrete and reinforcements for test specimens are detailed in Table 3.…”

Section: Design and Details Of Specimensmentioning

confidence: 99%

Seismic Performance Evaluation of RC Columns Retrofitted by 3D Textile Reinforced Mortars

Kim

Chang

2022

Materials

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The paper investigates the seismic performance of rectangular RC columns retrofitted by a newly developed 3D Textile Reinforced Mortar (TRM) panel. The 3D-TRM used in this study consists of two components: self-leveling mortar and 3D textiles. Firstly, the flexural capacity of the 3D-TRM panel was investigated through the four-point flexural test. Secondly, a total of five specimens were constructed and experimentally investigated through static cyclic loading tests with constant axial load. One specimen was a non-seismically designed column without any retrofit, while the others were strengthened with either the 3D-TRM panel or conventional Fiber Reinforced Polymer (FRP) sheets. Experimental results in terms of hysteretic behavior, ductility ratio, and energy dissipation are investigated and compared with the cases of specimens with conventional retrofitting methods and without any retrofit. The maximum lateral force, ductility, stiffness degradation, and energy dissipation of RC columns with 3D-TRM panels were significantly improved compared with the conventional RC column. Therefore, it is concluded that the proposed retrofitting method can improve the seismic performance of non-conforming RC columns.

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Section: Design and Details Of Specimensmentioning

confidence: 99%

Seismic Performance Evaluation of RC Columns Retrofitted by 3D Textile Reinforced Mortars

Kim

Chang

2022

Materials

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“…Reinforced concrete (RC) structures in seismic regions may reveal several deficiencies, such as inadequate lap splices of bottom steel bars within critical regions [1,2]. In some cases, slippage of the steel bars in critical regions may jeopardize the seismic performance of the structure and lead to premature collapse.…”

Section: Introductionmentioning

confidence: 99%

Advanced Composite Retrofit of RC Columns and Frames with Prior Damages—Pseudodynamic Finite Element Analyses and Design Approaches

Rousakis

Anagnostou

Fanaradelli

2021

Fibers

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This study develops three-dimensional (3D) finite element (FE) models of composite retrofits in deficient reinforced concrete (RC) columns and frames. The aim is to investigate critical cases of RC columns with inadequate lap splices of bars or corroded steel reinforcements and the beneficial effects of external FRP jacketing to avoid their premature failure and structural collapse. Similarly, the RC-frame FE models explore the effects of an innovative intervention that includes an orthoblock brick infill wall and an advanced seismic joint made of highly deformable polymer at the boundary interface with the RC frame. The experimental validation of the technique in RC frames is presented in earlier published papers by the authors (as well as for a four-column structure), revealing the potential to extend the contribution of the infills at high displacement ductility levels of the frames, while exhibiting limited infill damages. The analytical results of the advanced FE models of RC columns and frames compare well with the available experimental results. Therefore, this study’s research extends to critical cases of FE models of RC frames with inadequate lap splices or corroded steel reinforcements, without or with brick wall infills with seismic joints. The advanced pseudodynamic analyses reveal that for different reinforcement detailing of RC columns, the effects of inadequate lap-spliced bars may be more detrimental in isolated RC columns than in RC frames. It seems that in RC frames, additional critical regions without lap splices are engaged and redistribution of damage is observed. The detrimental effects of corroded steel bars are somewhat greater in bare RC frames than in isolated RC columns, as all reinforcements in the frame are considered corroded. Further, all critical cases of RC frames with prior damages at risk of collapse may receive the innovative composite retrofit and achieve higher base shear load than the original RC frame without corroded or lap-spliced bars, at comparable top displacement ductility. Finally, the FE analyses are utilized to propose modified design equations for the shear strength and chord rotation in cases of failure of columns with deficiencies or prior damages in RC structures.

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“…Among other materials, fiber-reinforced polymers (FRPs) have been used for retrofitting, mainly for providing additional external flexural or shear reinforcement to RC columns [4][5][6][7], beams [8][9][10][11], beam-column joints [12][13][14][15][16][17] and slabs [18,19]. Seifi et al [20] studied the effectiveness of the NSM technique for the flexural strengthening of columns, as well as the effectiveness of FRP jackets for the seismic retrofitting of beam-column joints.…”

Section: Introductionmentioning

confidence: 99%

Seismic Performance Enhancement of RC Columns Using Thin High-Strength RC Jackets and CFRP Jackets

Kalogeropoulos

Tsonos

2021

Fibers

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The existing non-ductile RC structures built prior to the 1960s–1970s were mainly conceived to carry only vertical loads. As a result, the columns of these structures demonstrate poor overall hysteresis behavior during strong earthquakes, dominated by brittle shear or/and premature excessive slipping of the inadequately lap-spliced reinforcement. In the present study, the effectiveness of two different strengthening systems (including either the wrapping of the columns by carbon-fiber-reinforced polymer textile or the use of thin high-strength reinforced concrete jackets), was experimentally and analytically investigated. The main variables examined were the strengthening material, the length of the lap splices and the amount of confinement provided by the jackets. Three cantilever column specimens were constructed without incorporating modern design code requirements for preserving seismic safety and structural integrity. Subsequently, the specimens were strengthened and subjected to earthquake-type loading. Their hysteresis performances were compared, while also evaluated with respect to the response of two similar original specimens and the behavior of a control one with continuous reinforcement, tested in a previous study. The predictions of the proposed analytical formulation for the hysteresis behavior of the strengthened specimens were satisfactorily verified by the experimental results.

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Cyclic Performance of RC Columns with Inadequate Lap Splices Strengthened with CFRP Jackets

Cited by 13 publications

References 18 publications

Seismic Performance Evaluation of RC Columns Retrofitted by 3D Textile Reinforced Mortars

Seismic Performance Evaluation of RC Columns Retrofitted by 3D Textile Reinforced Mortars

Advanced Composite Retrofit of RC Columns and Frames with Prior Damages—Pseudodynamic Finite Element Analyses and Design Approaches

Seismic Performance Enhancement of RC Columns Using Thin High-Strength RC Jackets and CFRP Jackets

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