钢筋钢纤维自密实混凝土梁弯曲性能及变形预测  

Flexural Behavior and Deflection Prediction of Self-Compacting Concrete Beam Reinforced with Steel Fibers and Conventional Reinforcement

作　　者：宁喜亮[1,2] 李剑峰 李媛媛 梁宇[5] NING Xiliang;LI Jianfeng;LI Yuanyuan;LIANG Yu(School of Architecture and Civil Engineering,Northeast Electric Power University,Jilin 132012,China;Key Lab of Electric Power Infrastructure Safety Assessment and Disaster Prevention of Jilin Province,Northeast Electric Power University,Jilin 132012,China;CGN New Energy Holdings Co.,LTD.,Harbin 150000,China;College of Geographical Sciences,Liaoning Normal University,Dalian 116029,China;Ordos Electric Power Supply Company,Ordos 017000,China)

机构地区：[1]东北电力大学建筑工程学院,吉林132012 [2]东北电力大学吉林省电力基础设施安全评估与灾害防治重点实验室,吉林132012 [3]中国广核新能源控股有限公司,哈尔滨150000 [4]辽宁师范大学地理科学学院,大连116029 [5]鄂尔多斯供电公司,鄂尔多斯017010

出　　处：《结构工程师》2023年第6期125-134,共10页Structural Engineers

基　　金：国家自然科学基金项目资助(51608100);吉林省科技厅自然基金面上项目资助(20230101331JC);吉林省教育厅科技项目资助(JJKH20220121KJ)。

摘　　要：基于有效截面惯性矩,提出了钢筋钢纤维自密实混凝土梁式构件(R/SFRSCC)瞬时弯曲挠度的简化模型。与普通钢筋混凝土梁式构件不同,R/SFRSCC需要考虑受拉区开裂截面钢纤维对梁式构件截面惯性矩的贡献,并基于内力平衡和应变协调计算了梁式构件开裂截面的中和轴高度。为研究钢纤维对钢筋自密实混凝土梁式构件瞬时弯曲变形性能的影响并验证预测模型的准确性,对9根钢筋钢纤维自密实混凝土梁式构件进行了四点抗弯试验,以钢纤维掺量和纵筋配筋率为主要变化参数。结果表明,钢纤维的掺入可以显著提高钢筋自密实混凝土梁式构件开裂后的截面抗弯刚度。正常使用阶段,掺入30 kg/m^(3)和50 kg/m^(3)的钢纤维可使钢筋自密实混凝土梁式构件开裂后的截面抗弯刚度提高26%~117%,但钢纤维的作用随着纵筋配筋率的增加而减弱。采用提出的瞬时挠度简化模型,对比了预测的与实测的钢筋屈服前荷载-跨中挠度曲线,两者吻合较好,模型可用于钢筋钢纤维自密实混凝土梁式构件瞬时弯曲变形的预测。Based on the effective second moment of area,a simple instantaneous deflection prediction on the steel rebar reinforced steel fiber reinforced self-compacting concrete(R/SFRSCC)beam is proposed.Different from the RC beam,the beneficial effect of steel fibers across a crack to the second moment of area of R/SFRSCC beam should be considered.In addition,the neutral axis height is calculated based on the equilibrium of force and strain compatibility of the beam.In order to investigate the effect of steel fibers on the instantaneous deflection of reinforced self-compacting concrete(R/SCC)beams and verify the accuracy of the prediction model of the instantaneous deflection,four-point bending test of nine self-compacting concrete beams co-reinforced with steel fibers and conventional reinforcements varying with steel fiber dosages and reinforcement ratios were performed.The results showed that the addition of steel fibers could significantly reduce the flexural stiffness of cracked R/SCC beams at service load.Compared with R/SCC beam without steel fibers,the flexural stiffness of R/SFRSCC beam increased by 26%~117%with the addition of 30 kg/m^(3) and 50 kg/m^(3) steel fibers,respectively.However,with the increasing of reinforcement ratio,the influence of steel fibers on the deformation of R/SFRSCC beam reduced.Compared with the predicted and measured loadmidspan deflection curves of R/SFRSCC beams before yielding of reinforcements,good agreement is obtained.It is illustrated that the predicted model can be used to predict the instantaneous deflection of R/SFRSCC beams.

关 键 词：钢纤维 自密实混凝土 跨中挠度 截面惯性矩 中和轴高度 

分 类 号：TU528[建筑科学—建筑技术科学]