基于软化拉-压杆模型的对角斜筋ECC连梁恢复力骨架曲线
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摘要
为了模拟对角斜筋超高韧性水泥基复合材料(ECC)连梁在低周反复荷载下的受力性能,提出了一种计算对角斜筋ECC连梁恢复力骨架曲线的理论模型.该模型基于软化拉-压杆模型,由ECC主拉-压杆、对角斜筋和次杆组成,并考虑了箍筋对ECC受压性能的约束影响以及ECC受压和受拉时的软化效应.基于此理论模型,提出了对角斜筋ECC连梁受剪承载力计算公式.选取11根对角斜筋ECC连梁实验数据进行验证,得到受剪承载力计算值与实验值之比的平均值为0.94,变异系数为0.09,说明计算结果与实验结果符合较好.在小跨高比连梁中,随着连梁跨高比的增大,对角斜筋和次杆抵抗的剪力逐渐增加,而ECC主拉-压杆抵抗的剪力则逐渐减小.
To simulate the behavior of diagonally reinforced engineered cementitious composite(ECC) coupling beam under reversed cyclic loadings, a theoretical model was proposed to predict the skeleton curve of the restoring force of the coupling beam. The proposed model was composed of the main diagonal ECC strut-and-tie, the diagonal reinforcement and the sub-struts based on the softened strut-and-tie model. The restraining effect of stirrups on the compression performance of ECC and the softening effect of ECC under compression and tension were also considered. Based on the proposed model, a formula for calculating the shear capacity of the diagonally reinforced ECC coupling beam was proposed. Eleven diagonally reinforced ECC coupling beam specimens were selected to verify the proposed model. The mean ratio of the calculated shear strength to the measured results is 0.94, and the coefficient of variation is 0.09, showing the good agreement between the calculated values and the experimental results. As for the coupling beams with the small span-to-depth ratio, the shear capacity provided by the diagonal reinforcement and the sub-struts increases with the increase of the span-to-depth ratio of the beam, while the shear capacity provided by the main ECC strut-and-tie decreases.
To simulate the behavior of diagonally reinforced engineered cementitious composite(ECC) coupling beam under reversed cyclic loadings, a theoretical model was proposed to predict the skeleton curve of the restoring force of the coupling beam. The proposed model was composed of the main diagonal ECC strut-and-tie, the diagonal reinforcement and the sub-struts based on the softened strut-and-tie model. The restraining effect of stirrups on the compression performance of ECC and the softening effect of ECC under compression and tension were also considered. Based on the proposed model, a formula for calculating the shear capacity of the diagonally reinforced ECC coupling beam was proposed. Eleven diagonally reinforced ECC coupling beam specimens were selected to verify the proposed model. The mean ratio of the calculated shear strength to the measured results is 0.94, and the coefficient of variation is 0.09, showing the good agreement between the calculated values and the experimental results. As for the coupling beams with the small span-to-depth ratio, the shear capacity provided by the diagonal reinforcement and the sub-struts increases with the increase of the span-to-depth ratio of the beam, while the shear capacity provided by the main ECC strut-and-tie decreases.
引文
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[16] 梁兴文,车佳玲,邓明科.对角斜筋小跨高比纤维增强混凝土连梁抗震性能试验研究[J].建筑结构学报,2013,34(8):135-141.DOI:10.14006/j.jzjgxb.2013.08.016.Liang X W,Che J L,Deng M K.Experimental research on seismic behavior of diagonally reinforced FRC coupling beams with small span-to-depth ratio[J].Journal of Building Structures,2013,34(8):135-141.DOI:10.14006/j.jzjgxb.2013.08.016.(in Chinese)
[17] Yun H D,Kim S W,Jeon E,et al.Effects of fibre-reinforced cement composites' ductility on the seismic performance of short coupling beams[J].Magazine of Concrete Research,2008,60(3):223-233.DOI:10.1680/macr.2007.00081.
[18] Han S W,Lee C S,Kwon H W,et al.Behaviour of fibre-reinforced beams with diagonal reinforcement[J].Magazine of Concrete Research,2015,67(24):1287-1300.DOI:10.1680/macr.14.00194.
[2] Shahrooz B M,Remmetter M E,Qin F.Seismic design and performance of composite coupled walls[J].Journal of Structural Engineering,1993,119(11):3291-3309.DOI:10.1061/(asce)0733-9445(1993)119:11(3291).
[3] Mattock A H,Gaafar G H.Strength of embedded steel sections as brackets[J].ACI Structural Journal,1982,79(2):83-93.DOI:10.14359/10883.
[4] Li V C,Leung C K Y.Steady-state and multiple cracking of short random fiber composites[J].Journal of Engineering Mechanics,1992,118(11):2246-2264.DOI:10.1061/(asce)0733-9399(1992)118:11(2246).
[5] Li V C,Mishra D K,Naaman A E,et al.On the shear behavior of engineered cementitious composites[J].Advanced Cement Based Materials,1994,1(3):142-149.DOI:10.1016/1065-7355(94)90045-0.
[6] Canbolat B A,Parra-Montesinos G J,Wight J K.Experimental study on the seismic behavior of high-performance fiber reinforced cement composite coupling beams[J].ACI Structural Journal,2005,102(1):159-166.DOI:10.14359/13541.
[7] 梁兴文,刘贞珍,邢朋涛,等.纤维增强混凝土对角斜筋小跨高比连梁抗震性能试验研究及受剪承载力分析[J].土木工程学报,2017,50(2):27-35.DOI:10.15951/j.tmgcxb.2017.02.004.Liang X W,Liu Z Z,Xing P T,et al.Experimental study on seismic behavior and shear capacity of diagonally reinforced fiber-reinforced concrete coupling beams with small span-to-depth ratio[J].China Civil Engineering Journal,2017,50(2):27-35.DOI:10.15951/j.tmgcxb.2017.02.004.(in Chinese)
[8] 中华人民共和国住房和城乡建设部.GB50010—2010 混凝土结构设计规范[S].北京:中国建筑工业出版社,2010.
[9] Hwang S J,Lee H J.Strength prediction for discontinuity regions by softened strut-and-tie model[J].Journal of Structural Engineering,2002,128(12):1519-1526.DOI:10.1061/(asce)0733-9445(2002)128:12(1519).
[10] Europe International Concrete Committee.Design of concrete structures:CEB-FIP model code 1990[S].London:Thomas Telford Ltd.,1993
[11] Neville A M,Dilger W H,Brooks J J.Creep of plain and structural concrete[M].London:Construction Press,1983:178-179
[12] Xoxa V.Investigating the shear characteristics of high performance fiber reinforced concrete [D].Toronto,Canada:University of Toronto,2003
[13] 李艳,刘泽军,王伟伟,等.箍筋约束ECC轴心受压性能试验研究[J].建筑结构学报,2017,38(7):164-173.DOI:10.14006/j.jzjgxb.2017.07.020.Li Y,Liu Z J,Wang W W,et al.Experimental study on axial compression performance of ECC confined with stirrups[J].Journal of Building Structures,2017,38(7):164-173.DOI:10.14006/j.jzjgxb.2017.07.020.(in Chinese)
[14] Mander J B,Priestley M J N,Park R.Theoretical stress-strain model for confined concrete[J].Journal of Structural Engineering,1988,114(8):1804-1826.DOI:10.1061/(asce)0733-9445(1988)114:8(1804).
[15] Nagai K,Suryanto B,Maekawa K.Space-averaged constitutive model for HPFRCCs with multi-directional cracking[J].ACI Materials Journal,2011,108(2):139-149.DOI:10.14359/51682307.
[16] 梁兴文,车佳玲,邓明科.对角斜筋小跨高比纤维增强混凝土连梁抗震性能试验研究[J].建筑结构学报,2013,34(8):135-141.DOI:10.14006/j.jzjgxb.2013.08.016.Liang X W,Che J L,Deng M K.Experimental research on seismic behavior of diagonally reinforced FRC coupling beams with small span-to-depth ratio[J].Journal of Building Structures,2013,34(8):135-141.DOI:10.14006/j.jzjgxb.2013.08.016.(in Chinese)
[17] Yun H D,Kim S W,Jeon E,et al.Effects of fibre-reinforced cement composites' ductility on the seismic performance of short coupling beams[J].Magazine of Concrete Research,2008,60(3):223-233.DOI:10.1680/macr.2007.00081.
[18] Han S W,Lee C S,Kwon H W,et al.Behaviour of fibre-reinforced beams with diagonal reinforcement[J].Magazine of Concrete Research,2015,67(24):1287-1300.DOI:10.1680/macr.14.00194.