西安建筑科技大学学报(自然科学版)

以两点对称荷载作用下无粘结预应力混凝土简支梁为研究对象,基于混凝土梁的整体变形及塑性铰分布特点,通过对梁实际曲率分布进行简化后计算得出预应力筋的应力增量,进一步提出了无粘结预应力混凝土简支梁受弯承载力的计算方法.通过77根无粘结预应力混凝土梁的试验数据对建议抗弯承载力计算模型进行验证,并将计算结果与美国ACI318规范的计算模型及其它模型的计算结果进行了对比.结果表明:无粘结预应力混凝土梁受弯承载力的试验值与理论预测值之比的平均值为1.047,标准差为0.077,变异系数为0.073,二者吻合较好; 与其他计算模型的计算结果相比,本文建议计算模型较真实地反映了预应力混凝土梁的曲率分布,可更准确的计算无粘结预应力混凝土梁的抗弯承载力.

By selecting the simply supported concrete beam prestressed with unbonded steel tendons under four-point loading as the research object, the stress increment of prestressed reinforcement was calculated by simplifying the actual curvature distribution. And a calculation model of flexural bearing capacity of the unbonded prestressed concrete beam was put forward based on the overall deformation and plastic hinge distribution characteristics of the concrete beam. The flexural bearing capacity calculation model was verified by 77 unbonded prestressed concrete beams, and was compared with ACI 318 code and other model. Good agreement between experimental results and predicted results was achieved with an average ratio of test values to predicted values being 1.046, the variance being 0.071, and the coefficient of variation being 0.256. Compared with the other models, the proposed model in this paper reasonably reflects the real curvature distribution of the prestressed concrete beams, and the flexural bearing capacity can be calculated more accurately.

引言
1 抗弯承载力计算模型的提出
2 预应力混凝土梁极限承载力计算
3 模型验证
4 结论

图1 对称集中荷载作用下无粘结预应力混凝土梁<br/>Fig.1 Simply supported concrete beam prestressed with unbonded tendons under four-point loading

图1 对称集中荷载作用下无粘结预应力混凝土梁
Fig.1 Simply supported concrete beam prestressed with unbonded tendons under four-point loading

图2 无粘结预应力混凝土梁的曲率分布<br/>Fig.2 Curvature distribution for unbonded pretressed concrete beam

图2 无粘结预应力混凝土梁的曲率分布
Fig.2 Curvature distribution for unbonded pretressed concrete beam

图3 无粘结预应力混凝土梁截面应力及其合力<br/>Fig.3 Stresses and forces of unbonded prestressed concrete beam cross section

图3 无粘结预应力混凝土梁截面应力及其合力
Fig.3 Stresses and forces of unbonded prestressed concrete beam cross section

图4 受弯承载力计算流程图<br/>Fig.4 Flow chat for the calculation of flexural bearing capacity

图4 受弯承载力计算流程图
Fig.4 Flow chat for the calculation of flexural bearing capacity

图5 受弯承载力的试验值与计算值<br/>Fig.5 Test values and predicted values of the flexural strength

图5 受弯承载力的试验值与计算值
Fig.5 Test values and predicted values of the flexural strength

表1 无粘结预应力混凝土梁抗弯承载力试验结果与计算结果对比<br/>Tab.1 Comparison of flexural strength between test results and prediction results of unbonded prestressed reinforced concrete

表1 无粘结预应力混凝土梁抗弯承载力试验结果与计算结果对比
Tab.1 Comparison of flexural strength between test results and prediction results of unbonded prestressed reinforced concrete

[1]汤永净,程付扬.无粘结部分预应力筋极限应力增量评析[J].工业建筑, 2009(1): 354-356.
[2]中华人民共和国住房和城乡建设部.无粘结预应力混凝土结构技术规程:JGJ92-2016[S].北京: 中国建筑工业出版社,2016.
[3]杜拱辰,陶学康.部分预应力混凝土梁无粘结筋极限应力的研究[J].建筑结构学报, 1985, 6(6): 2-13.
[4]宋永发, 王清湘.无粘结部分预应力高强混凝土梁正截面承载力计算[J].大连理工大学学报, 1996, 40(2): 224-229.
[5]BAKER A L L. A plastic theory of design for ordinary reinforced and prestressed concrete including moment redistribution in continuous members[J].Magazine of Concrete Research, 1949, 1(2): 57-66.
[6]NAAMAN A E, ALKHAIRI F M. Stress at ultimate in un-bonded prestressing tendons: Patr1-evalutation of the state-of-art[J].ACI Structural Journal, 1991, 88(5): 95-108.
[7]PANELL F N. Ultimate moment of resistance of unbonded pre-stressed concrete beams[J].Magazine of Concrete Reseach, 1969, 21(66): 43-54.
[8]杜进生, 刘西拉. 基于结构变形的无粘结预应力筋应力变化研究[J].土木工程学报, 2003, 36(8): 12-19.
[9]申同生, 戴公连, 方淑君. 求解无粘结预应力混凝土梁力筋应力增量的能量法[J].中外公路, 2000, 20(5): 15-17.
[10]郜剑峰. 无粘结预应力混凝土超静定结构力筋应力增量计算的能量法[J].长沙铁道学院学报, 2003, 21(1): 43-46.
[11]熊正元, 王一军. 无粘结预应力混凝土超静定结构力筋应力计算的能量法[J].建筑结构, 2003(4): 76-77.
[12]高月婷, 胡亚军. 无粘结预应力筋应力计算的能量法[J].铁道建筑, 2007(4): 16-18.
[13]HARAJLI M H, HIJAZI S A. Evaluation of the ultimate steel stress in partially prestressed concrete members[J].PCI Journal, 1991, 36(1): 62-82.
[14]WARWARUK J, SOZEN M A, SIESS C P. Strength and behavior in flexure of prestressed concrete beams[J].Journal of Clinical Investigation, 1960, 57(3): 551-8.
[15]CORLEY W. Rotational capacity of reinforced concrete beams[J].Journal of the Structural Division, 1966, 92(5): 121-146
[16]MATTOCK, A H. Discussion of “Rotational Capacity of Concrete Beams.”[J].Journal of the Structural Division, l967, 93(2): 519-522.
[17]WHITNEY C S. Design of reinforced concrete members under flexure or combined flexure and direct compression[J].Journal Proceedings. 1937, 33(3):483-498.
[18]PANNELL F N, TAM A. The ultimate moment of resistance of unbonded prestressed concrete beams[J].Magazine of Concrete Research, 1976, 28(97): 203-208.
[19]LIU Jianxing, ZHANG Shu. The experimental study of the ultimate strength, crack and defection of unbonded partially prestressed concrete beams[J].Journal of Hunan University, 1987, 14(3): 1-15.
[20]王逸, 杜拱辰. 跨中集中荷载下部分预应力梁无粘结筋极限应力的研究[J].建筑结构学报, 1991, 12(6): 42-52.
[21]LEE D H, KANG S K. Flexural strength of prestressed concrete members with unbonded tendons[J].Structural Engineering & Mechanics, 2011, 38(5): 675-696.
[22]李昕桐. HRB500级钢筋无粘结部分预应力混凝土梁受力性能试验研究[D].河北: 河北工业大学, 2012.
[23]YANG, K H, KANG T H K. Prediction of stress at ultimate in unbonded tendons based on an equivalent strain- distributionfactor[J].ACI Structural Journal, 2011, 108(2): 217-226.
[24]YANG K H, MUN J H, KIM G H. Flexural behavior of post-tensioned normal-strength lightweight concrete one-way slabs[J].Engineering Structures, 2013, 56: 1295-1307.
[25]ACI Committee 318. Building code requirements for structural concrete and commentary:ACI 318R-11[S].Detroit:American Concrete Institute, 2011.

备注

引言

1 抗弯承载力计算模型的提出

2 预应力混凝土梁极限承载力计算

3 模型验证

4 结论

期刊信息