RESEARCH ON CALCULATION METHOD FOR AXIAL COMPRESSIVE STRENGTH AND ULTIMATE COMPRESSIVE STRAIN OF RECTANGULAR CONCRETE CONFINED WITH FRP
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摘要: 轴压荷载下纤维增强复材(FRP)约束混凝土应力-应变本构关系可分为强化型和软化型两类约束模型,其在极限状态时所固有的轴压应力及应变构成了各自本构的参数基础,准确计算这些本构参数可为FRP约束混凝土结构的性能评估提供判别依据。通过对现有FRP约束矩形混凝土抗压强度和极限压应变经验模型的性能进行综合评价,表明已有经验模型普遍存在通用性差、预测准确性低以及离散性大等问题。针对传统预测模型的局限性,基于反向传播神经网络,分别建立了强化型和软化型FRP约束矩形混凝土抗压强度和极限压应变预测模型。研究结果表明:神经网络模型不仅能反映各类控制参数对轴压应力及应变的影响,且相比于已有经验模型,基于神经网络模型的计算值和试验值吻合更好,偏差和随机性都显著减小,保证了预测结果的准确性和稳定性。Abstract: The stress-strain constitutive relation of FRP-confined concrete can be divided into two categories of constraint models under axial load:work hardening and softening. The intrinsic axial compressive stress and strain in the ultimate state constitute the parameter basis of their constitutions. Calculating these constitutive parameters accurately can provide a discrimination criteria for evaluating the performance of FRP-confined concrete structures. The performance of the existing empirical models about compressive strength and ultimate compressive strain of rectangular concrete confined with FRP was evaluated comprehensively, and the results showed that the existing empirical models generally showed poor universality, low prediction accuracy and high dispersion. Aiming at the limitation of traditional prediction models, the prediction models of compressive strength and ultimate compressive strain for both hardening and softening types of rectangular concrete confined with FRP were constructed respectively based on back-propagation artificial neural network. The research results indicated that the neural network models could not only reflect the influence of various control parameters on the axial compressive stress and strain, but also the calculated values based on the neural network models were in better agreement with the experimental values when compared with the existing empirical models; moreover, the deviation and randomness were significantly decreased,so as to ensure the accuracy and stability of prediction results.
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[1] 滕锦光.新材料组合结构[J].土木工程学报, 2018, 51(12):1-11. [2] 曹玉贵, 张扬, 侯灿, 等.FRP约束损伤混凝土环向应变-轴向应变关系[J].哈尔滨工业大学学报, 2020, 52(9):85-91. [3] BAI Y L, DAI J G, MOHAMMADI M, et al.Stiffness-Based Design-Oriented Compressive Stress-Strain Model for Large-Rupture-Strain (LRS) FRP-Confined Concrete[J/OL].Composite Structures, 2019, 223.DOI: 10.1016/j.compstruct.2019.110953. [4] 张扬, 曹玉贵, 胡志礼.基于Griffith破坏准则的FRP约束未损伤混凝土和损伤混凝土的抗压强度统一模型[J].复合材料学报, 2020, 37(9):2358-2366. [5] RICHART F E, BRANDTZAEG A, BROWN R L.A Study of the Failure of Concrete Under Combined Compressive Stresses[J].University of Illinois Bulletin, 1928, 26(12):185. [6] CHAALLAL O, SHAHAWY M.Performance of Fiber-Reinforced Polymer-Wrapped Reinforced Concrete Column Under Combined Axial Flexural Loading[J].ACI Structural Journal, 2000, 97(4):659-668. [7] LAM L, TENG J.Design-Oriented Stress-Strain Model for FRP-Confined Concrete[J].Journal of Reinforced Plastics and Composites, 2003, 22(13):1149. [8] AL-SALLOUM Y A.Influence of Edge Sharpness on the Strength of Square Concrete Columns Confined with FRP Composite Laminates[J].Composites Part B, 2006, 38(5):640-650. [9] WANG L M, WU Y F.Effect of Corner Radius on the Performance of CFRP-Confined Square Concrete Columns:Test[J].Engineering Structures, 2008, 30(2):493-505. [10] NISTICÒ N, PALLINI F, ROUSAKIS T, et al.Peak Strength and Ultimate Strain Prediction for FRP Confined Square and Circular Concrete Sections[J].Composites Part B, 2014, 67:543-554. [11] 魏洋, 吴刚, 吴智深, 等.FRP约束混凝土矩形柱有软化段时的应力-应变关系研究[J].土木工程学报, 2008(3):21-28. [12] SHEHATA I, CARNEIRO L, SHEHATA L.Strength of Short Concrete Columns Confined with CFRP Sheets[J].Materials and Structures, 2002, 35(245):50-58. [13] YOUSSEF M N, FENG M Q, MOSALLAM A S.Stress-Strain Model for Concrete Confined by FRP Composites[J].Composites Part B, 2007, 38(5):614-628. [14] TOUTANJI H, HAN M, GILBERT J, et al.Behavior of Large-Scale Rectangular Columns Confined with FRP Composites[J].Journal of Composites for Construction, 2010, 14(1):62-71. [15] WU Y F, WEI Y Y.Unified Stress-Strain Model of Concrete for FRP-Confined Columns[J].Construction and Building Materials, 2012, 26(1):381-392. [16] PHAM T M, HADI M N S.Stress Prediction Model for FRP Confined Rectangular Concrete Columns with Rounded Corners[J].Journal of Composites for Construction, 2014, 18(1):1-10. [17] CAO Y G, WU Y F, LI X Q.Unified Model for Evaluating Ultimate Strain of FRP Confined Concrete Based on Energy Method[J].Construction and Building Materials, 2016, 103:23-35. [18] JIANG K J, HAN Q, BAI Y L, et al.Data-Driven Ultimate Conditions Prediction and Stress-Strain Model for FRP-Confined Concrete[J/OL].Composite Structures, 2020, 242.DOI: 10.1016/j.compstruct.2020.112094. [19] FANARADELLI T, ROUSAKIS T, KARABINIS A.Reinforced Concrete Columns of Square and Rectangular Section, Confined with FRP-Prediction of Stress and Strain at Failure[J/OL].Composites Part B:Engineering, 2019, 174.DOI: 10.1016/j.compositesb.2019.107046. [20] CHEN W G, XU J J, DONG M H, et al.Data-Driven Analysis on Ultimate Axial Strain of FRP-Confined Concrete Cylinders Based on Explicit and Implicit Algorithms[J/OL].Composite Structures, 2021, 268.DOI: 10.1016/j.compstruct.2021.113904. [21] XU J J, ZHAO X Y, YU Y, et al.Parametric Sensitivity Analysis and Modelling of Mechanical Properties of Normal-and High-Strength Recycled Aggregate Concrete Using Grey Theory, Multiple Nonlinear Regression and Artificial Neural Networks[J].Construction and Building Materials, 2019, 211:479-491. [22] WANG D Y, WANG Z Y, SMITH S T, et al.Size Effect on Axial Stress-Strain Behavior of CFRP-Confined Square Concrete Columns[J].Construction and Building Materials, 2016, 118:116-126. [23] 于峰, 武萍.FRP约束矩形混凝土柱应力-应变模型[J].建筑结构, 2011, 41(1):83-86.
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