体外预应力梁动力特性的能量法分析
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摘要
不引入解析法中体外筋预拉力增量与梁中点振动位移成正比的假设,提出用能量法分析体外预应力梁动力特性。由于不引入解析法中的假设,梁自振频率也更准确,与数值解吻合良好。计算结果表明:解析法低估了体外筋对第1自振频率效应;高估了对第2自振频率效应;体外预应力筋对第1自振频率影响较大,对高阶的频率影响很小,可以不考虑其影响;随着体外筋面积和偏心距的增加,梁的第1自振频率也随之增加。在理论上,体外预应力能减小梁的自振频率,而体内预应力对梁的自振频率没有影响。
The assumption that the prestress increment of external tendon is proportional to the mid-span vibration displacement of a beam in the analytical method was not adopted.The energy method to analyze the dynamic behavior of an externally prestressed beam was proposed.Due to not adopting the assumption in the analytical method,the natural vibration frequencies were more accurate,and ageed well with the numerical results.The calculation results showed that the effect of external tendon on the 1st frequency is underestimated by the analytical method,and its effect on the 2nd frequency is overestimated;the influence of externally prestressed tendon on the 1st frequency is significant,but its influence on higher natural frequencies is slight and can be neglected;with increase in area and eccentricity of external tendon,the 1st frequency of the beam increases.Theoretically,external prestress can reduce the 1st frequency of a beam,but,internal prestress has no influence on the natural frequencies of a beam.
The assumption that the prestress increment of external tendon is proportional to the mid-span vibration displacement of a beam in the analytical method was not adopted.The energy method to analyze the dynamic behavior of an externally prestressed beam was proposed.Due to not adopting the assumption in the analytical method,the natural vibration frequencies were more accurate,and ageed well with the numerical results.The calculation results showed that the effect of external tendon on the 1st frequency is underestimated by the analytical method,and its effect on the 2nd frequency is overestimated;the influence of externally prestressed tendon on the 1st frequency is significant,but its influence on higher natural frequencies is slight and can be neglected;with increase in area and eccentricity of external tendon,the 1st frequency of the beam increases.Theoretically,external prestress can reduce the 1st frequency of a beam,but,internal prestress has no influence on the natural frequencies of a beam.
引文
[1]熊学玉.体外预应力结构设计[M].北京:中国建筑工业出版社,2005.123-139.
[2]方德平.考虑P-效应的体外预应力梁的M-分析法[J].工程力学,2002,19(4):113-117.
[3]Saiid M,Douglas B,Feng S.Prestress force effect on vibration frequency of concrete bridges[J].Journal of Structural Engineering,ASCE,1994,120(7):2233-2241.
[4]Miyagawa A,Tei K,Nakamura H.Behavior of prestressed beam strengthened with external tendons[J].Journal ofStructural Engineering.2000,126(9):1030-1037.
[5]熊学玉,王寿生.体外预应力梁振动特性的分析与研究[J].地震工程与工程振动,2005,25(2):55-61.
[6]刘宏伟,张伟,庄惠平.预加力对梁的动力影响分析[J].黑龙江科技学院学报,2002,12(3):37-39.
[7]楼梦麟,洪婷婷.预应力梁横向振动分析的模态摄动法[J].工程力学,2006,23(1):107-111.
[8]楼梦麟,洪婷婷.体外预应力梁动力特性的分析方法[J].同济大学学报(自然科学版),2006,34(10):1284-1288.
[9]楼梦麟,吴京宁.复杂梁动力问题的近似分析方法[J].上海力学,1997,18(3):234-240.
[10]Dall’Asta A,Dezi L,et al.Prestress force effect on vibration frequency of concrete bridges[J].Journal of Structural Engineering,ASCE.1996,122(4):458-460.
[11]张耀庭,李宏健.全预应力砼梁动力性能试验研究[J].工程力学,2008,25(增刊I):71-751.
[12]李瑞鸽,张耀庭,邹冰川.基于正交异性材料的预应力梁频率的试验研究[J].工程力学,2008,25(2):116-121.
[2]方德平.考虑P-效应的体外预应力梁的M-分析法[J].工程力学,2002,19(4):113-117.
[3]Saiid M,Douglas B,Feng S.Prestress force effect on vibration frequency of concrete bridges[J].Journal of Structural Engineering,ASCE,1994,120(7):2233-2241.
[4]Miyagawa A,Tei K,Nakamura H.Behavior of prestressed beam strengthened with external tendons[J].Journal ofStructural Engineering.2000,126(9):1030-1037.
[5]熊学玉,王寿生.体外预应力梁振动特性的分析与研究[J].地震工程与工程振动,2005,25(2):55-61.
[6]刘宏伟,张伟,庄惠平.预加力对梁的动力影响分析[J].黑龙江科技学院学报,2002,12(3):37-39.
[7]楼梦麟,洪婷婷.预应力梁横向振动分析的模态摄动法[J].工程力学,2006,23(1):107-111.
[8]楼梦麟,洪婷婷.体外预应力梁动力特性的分析方法[J].同济大学学报(自然科学版),2006,34(10):1284-1288.
[9]楼梦麟,吴京宁.复杂梁动力问题的近似分析方法[J].上海力学,1997,18(3):234-240.
[10]Dall’Asta A,Dezi L,et al.Prestress force effect on vibration frequency of concrete bridges[J].Journal of Structural Engineering,ASCE.1996,122(4):458-460.
[11]张耀庭,李宏健.全预应力砼梁动力性能试验研究[J].工程力学,2008,25(增刊I):71-751.
[12]李瑞鸽,张耀庭,邹冰川.基于正交异性材料的预应力梁频率的试验研究[J].工程力学,2008,25(2):116-121.
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