A new predictive model for FRCM-confined columns: A reflection on the composite behavior at peak stress

Ameli, Zahra; D’Antino, Tommaso; Carloni, Christian

doi:10.1016/j.conbuildmat.2022.127534

Cited by 13 publications

(9 citation statements)

References 55 publications

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“…In fact, design codes and guidelines do not allow the use of FRP confinement for members featuring a side aspect ratio greater than a certain limit (see Ref. [ 43 ]). The ACI 440.2R-17 guidelines [ 31 ] do not recommend using FRP wrapping for RC columns with a sectional aspect ratio greater than 2.0.…”

Section: Introductionmentioning

confidence: 99%

Performance of Concentrically Loaded RC Wall-like Columns Upgraded with Innovative Hybrid NSM/CFRP System

et al. 2023

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In RC (reinforced concrete) frame structures, wall-like columns are laid within the space occupied by masonry walls to maximize usable space and thus minimize the column projections into the usable area. These columns often require strengthening owing to various reasons, including increasing the number of stories, changes in building usage, and others. The use of a hybrid system comprising NSM (near-surface mounted) steel rebars combined with CFRP (carbon-fiber reinforced polymer) laminates may be considered a sound technique for strengthening such wall-like building columns. The prime aim of this study is to devise an efficient scheme using a hybrid NSM/CFRP system to strengthen existing RC wall-like columns. Six half-scale RC wall-like columns were prepared and tested under monotonic concentric axial compression. Two columns were unstrengthened to serve as control specimens (CW1 and CW2), and four specimens were strengthened using four different schemes (SW1, SW2, SW3, and SW4). As favored by architects, all strengthening schemes were designed so that the dimensions of the column cross-section were not increased. The effects of strengthening schemes on the enhancement of axial capacity, energy dissipated, and stiffness were evaluated to find the most efficient scheme. Among the four studied schemes, using vertical continuous NSM rebars in combination with the wrapping of the three CFRP layers onto the exterior column surface (in specimen SW2) was the most efficient as it enhanced the ultimate load capacity by 80%. Three-dimensional FE (finite element) analysis was also conducted to predict the response of test specimens. The test results matched well with the FE outputs, which justified the accuracy of the used constitutive models for concrete, steel rebars, and CFRP sheets.

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Section: Introductionmentioning

confidence: 99%

Performance of Concentrically Loaded RC Wall-like Columns Upgraded with Innovative Hybrid NSM/CFRP System

et al. 2023

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“…On the other hand, low-quality matrix does not allow for the performance of the fibers to develop if they are prematurely exposed, and the stress is poorly transferred to the fibers when a crack opens within the matrix. Some of the cited parameters have been the variables of experimental programs (e.g., column shape and performance of masonry; fibers, matrix behavior, strength, amount, to cite some examples [29][30][31][32][33][34][35][36]) and they have been included in available theoretical confinement models for confined members with FRP or FRCM (see [24,25,37] for a review). Unfortunately, such theoretical models are still not able to simulate all the experimental variability found in the cited programs.…”

Section: Introductionmentioning

confidence: 99%

Effects of Defects on Masonry Confinement with Inorganic Matrix Composites

2023

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Fabric-reinforced cementitious matrix (FRCM) composites are currently considered a suitable solution for strengthening existing structures. Confinement applications are still being investigated, since experimental programs showed significant scatter in the results and theoretical models are struggling to become established as a consequence. The main aim of this study is the identification of potential sources of scatter in the confinement efficiency of FRCM wrappings, in defects such as fiber slip within the matrix or imperfect straightening of fibers, or premature failure of fibers once exposed after complete matrix cracking. A theoretical incremental approach is proposed to simulate such effects. The approach is incremental, but not iterative, so that no convergence is required and the incremental step size has an impact only on the smoothness of the nonlinear theoretical stress vs. strain curves of the FRCM confined material, among other simulation results. Theoretical results are compared to experimental outcomes of previous tests. The main source of variability can be identified in the cited defects, and the approach can be considered satisfactory to simulate the effects of defects and the high scatter found in experimental results; however, further uncertainties in the behavior of materials can be included in future refinements of this study.

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“…One previous study proposed a peak axial stress formula for concrete cylinders that considers variables such as the type of concrete cylinder cross-section (round, square), size, strength of concrete, and type of fibers [21]. However, the peak axial stress formula is limited to the evaluation of material properties, and applicability to actual size RC columns is minimal.…”

Section: Introductionmentioning

confidence: 99%

Prediction of Flexural Strength of RC Circular Columns Considering Lateral Confinement Effects of FRCM and Transverse Steel Reinforcement

Jo,

Kim,

Kim

et al. 2023

Buildings

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There has recently been growing interest in making a sustainable and durable fiber reinforced cementitious matrix (FRCM) to improve the seismic performance of RC column members. However, most studies evaluating the lateral confinement effect on FRCM jacketing concrete have excluded the confinement effect of transverse steel reinforcement and focused solely on mechanical properties. This paper, based on existing studies, proposes a peak axial stress formula that considers the lateral confinement effects of FRCM composite and transverse steel reinforcement. Additionally, the study assesses the structural performance of FRCM composites with flexural strengthening in actual size RC circular columns and predicts the maximum flexural strength by applying the proposed formula. The proposed peak axial stress formula, considering the influence of transverse reinforcement, was compared with the experimental value (databases) and the predicted value, and the suitability was confirmed with a standard deviation of 27.6% and a coefficient of variation of 0.856. In addition, the maximum flexural strength of actual size RC circular columns predicted by applying this formula ranged from 0.97 to 1.02, which effectively predicted the experimental values.

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A new predictive model for FRCM-confined columns: A reflection on the composite behavior at peak stress

Cited by 13 publications

References 55 publications

Performance of Concentrically Loaded RC Wall-like Columns Upgraded with Innovative Hybrid NSM/CFRP System

Performance of Concentrically Loaded RC Wall-like Columns Upgraded with Innovative Hybrid NSM/CFRP System

Effects of Defects on Masonry Confinement with Inorganic Matrix Composites

Prediction of Flexural Strength of RC Circular Columns Considering Lateral Confinement Effects of FRCM and Transverse Steel Reinforcement

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