体外预应力连续梁动力性能的能量法二阶分析  

Second order analysis for dynamic performance of externally prestressed continuous beams with energy method

作　　者：方德平[1] FANG Deping(College of Civil Engineering,Huaqiao University,Xiamen 361021,China)

机构地区：[1]华侨大学土木工程学院,厦门361021

出　　处：《振动与冲击》2018年第17期135-140,154,共7页Journal of Vibration and Shock

基　　金：国家自然科学基金(51578253);厦门市科技计划项目(3502Z20172014)

摘　　要：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影响系数的大小,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黏结筋,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黏结预压力的零效应。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。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 

分 类 号：TU375.1[建筑科学—结构工程]