选用普通连续梁的正对称和反对称振型作为2跨体外预应力连续梁的振型，精细地分析了体外筋的第1阶和第2阶变形，基于能量法，计算了体外预应力连续梁的自振频率。计算结果说明：体外预压力存在压缩软化效应，该效应可由0~1之间的影响系数来表示；转向座的数量决定了的影响系数大小，跨间无转向座时，影响系数等于1，体外预压力与外轴力具有相同的压缩软化效应；增加转向座数量，体外筋逐渐接近于无粘结筋，影响系数从1逐渐降低至接近于0，体外预压力的压缩软化效应接近于无粘结预压力的零效应。当跨间至少有1个转向座，影响系数明显小于1，可略去体外预压力的压缩软化效应；增加体外筋偏心距和面积，只明显提高梁第1阶正对称振型的自振频率；可略去体外筋对所有反对称振型、第1阶以外的正对称振型自振频率的影响。
Abstract
Symmetric and antisymmetric vibration modes of an ordinary continuous beam were taken as vibration modes of a 2-span externally prestressed continuous beam,the 1st and 2nd order deformations of external tendon were precisely analyzed. Based on the energy method,the natural frequencies of the externally prestressed continuous beam were calculated. The calculation results indicated that external precompression force has the compression softening effect,this effect can be expressed using an influence coefficient with the range of 0—1; the influence coefficient value is determined by the number of deviators; if there are no deviators within a span,the influence coefficient is 1; the compression softening effect of external precompression force is the same as that of external axial force; if the number of deviators increases,external tendon is gradually close to unbonded one,the influence coefficient gradually drops from 1 to near 0,the compression softening effect of external precompression force is close to zero effect of unbonded precompression force; if there is at least 1 deviator within a span,the influence coefficient is much less than 1,the compression softening effect of external precompression force can be neglected; if the eccentricity and area of external tendon increase,only the natural frequency of the beam’s 1st order symmetric vibration shape increases obviously,the effects of external tendon on natural frequencies of the beam’s all antisymmetric vibration modes and symmetric ones except the 1st order one are negligible.
关键词
体外预应力 /
连续梁 /
压缩软化 /
自振频率 /
二阶效应 /
能量法
{{custom_keyword}} /
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[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
Xiong Xueyu. Design of Externally Prestressed Structure [M]. Beijing: China Architecture & Building Press, 2005: 123-139 (in Chinese)
[2] 杜进生，区达光．体外预应力筋的极限应力：既有典型计算方法评述[J]．工程力学，2010，27(9)：63-68
Du Jinsheng, Francis Tk Au. Ultimate stress in external tendons: comments on the existing typical methods [J]. Engineering Mechanics . 2010, 27(9): 63-68 (in Chinese)
[3] Ayaho Miyagawa, Katsuji Tei, Hideaki Nakamura, etal. Behavior of prestressed beam strengthened with external tendons [J]. Journal of Structural Engineering, ASCE. 2000, 126(9): 1033-1044
[4] 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
Xiong Xueyu, Wang Shousheng. Analysis and research of externally prestressed beam vibration behavior [J]. Earthquake Engineering and Engineering Vibration. 2005, 25(2): 55-61 (in Chinese)
[5] 焦春节，丁洁民．体外预应力钢—混凝土组合连续梁自振频率分析[J]．工程力学，2011，28(2)：193-197
Jiao Chunjie, Ding Jiemin. Analysis of natural frequency of prestressed composite beam with external tendons [J]. Engineering Mechanics. 2011, 28(2): 193-197 (in Chinese)
[6] 熊学玉，高峰，李阳．体外预应力连续梁振动特性的分析与研究[J]．振动与冲击，2011，30(6)：104-108
Xiong Xueyu, Gao Feng, Li Yang. Analysis on vibration behavior of externally prestressed concrete continuous beam[J]. Journal of Vibration and shock. 2011, 30(6): 104-108 (in Chinese)
[7] 方德平，王全凤．体外预应力梁动力特性分析的一种新方法[J]．地震工程与工程震动，2010，30(4)：66-71
Fang Deping, Wang Quanfeng. A new method for analyzing dynamic behavior of externally prestressed beam [J]. Journal of Earthquake Engineering and Engineering Vibration. 2010, 30(4): 66-71 (in Chinese)
[8] 方德平．体外预应力连续梁动力特性的等效刚度分析法[J]．地震工程与工程震动，2014，34(6)：153-159
Fang Deping. Equivalent stiffness method for analyzing dynamic behavior of externally prestressed continuous beam [J]. Earthquake Engineering and Engineering Vibration. 2014, 34(6): 153-159 (in Chinese)
[9] M. Saiidi, B. Douglas, S. Feng, Prestress. force effect on vibration frequency of concrete bridge [J]. ASCE Journal of Structural Engineering. 1994, 120(7): 2233-2241
[10] A. Dallasta, L. Dezi. Prestress force effect on vibration frequency of concrete bridge-discussion [J]. ASCE Journal of Structural Engineering. 1996, 122(4): 458-458
[11] G. Deak. Prestress force effect on vibration frequency of concrete bridge-discussion [J]. ASCE Journal of Structural Engineering. 1996, 122(4): 458-459
[12] S.K. Jain, S.C. Goel, Prestress. force effect on vibration frequency of concrete bridge-discussion [J]. ASCE Journal of Structural Engineering. 1996, 122(4): 459-460
[13] O. Hamed, Y. Frostig. Natural frequencies of bonded and unbonded prestressed beams-prestress force effects [J]. Journal of Sound and Vibration. 2006, 295(1-2): 28-39
[14] De-Ping Fang. Second order effects of external prestress on frequencies of simply supported beam by energy method [J]. Structural Engineering and Mechanics, 2014, 52(4): 687-699
[15] 方德平，钟明镜．用能量法分析体外预压力对简支梁动力性能的二阶效应[J]．动力学与控制学报，2016，14(5)：463-468
Fang Deping, Zhong Mingjing. Second order effect of external tendon compression on dynamic behavior of simply supported beam by energy method [J].Journal of Dynamics and Control. 2016, 14(5): 436-468 (in Chinese)
{{custom_fnGroup.title_cn}}
脚注
{{custom_fn.content}}
PDF(712 KB)
