【作者】 刘波；

【导师】 贺拴海；

【作者基本信息】 长安大学 ， 桥梁与隧道工程， 2008， 硕士

【摘要】 交通运输的迅速发展在国民经济的高速发展中发挥着越来越重要的作用,然而随着车流量的迅速增加,尤其是各种大型超载超重车辆的出现,给现有桥梁带来了巨大的挑战。致使各类桥梁结构在反复荷载作用下凸现出各种病害,如桥梁在正常服役期内出现较大变形和裂缝等,严重的影响到桥梁的线形甚至危及到桥梁的安全性能。根据国内外相关资料的调查研究表明,认为钢筋混凝土梁和预应力混凝土梁的疲劳失效是结构物的主要破坏形式之一。本文作为交通部科技项目《大跨径预应力混凝土梁桥主梁下挠原因分析及对策项目》专题三“大跨径预应力混凝土梁桥反复移动荷载的作用效应研究”的前期研究工作。通过调查分析国内外对钢筋混凝土和预应力混凝土梁的疲劳性能的研究概况,为后续研究工作的顺利展开奠定了坚实的基础。主要研究成果如下:1)总结影响混凝土疲劳性能主要因素,通过分析对比不同学者对混凝土结构在重复荷载作用下的疲劳失效模式,认为在重复荷载作用下最小应力水平对混凝土的抗压疲劳性能影比较敏感,其值随最小应力水平增大而增大;变形模量随重复荷载的次数成反比关系。2)论文介绍钢筋混凝土疲劳性能在国内外的研究状况,分析对比了不同学者对计算光圆钢筋、变形钢筋的疲劳强度S-N曲线之间的特点,分析钢筋混凝土梁的裂缝宽度随荷载重复次数N的增加而增大。3)调查分析预应力混凝土梁正截面抗弯疲劳性能,归纳受弯构件在重复荷载作用下正截面疲劳破坏形态。通过分析对比发现预应力筋的应力随重复次数N的增大而增大,预应力度对挠度的影响比较敏感,预应力度的增大可以有效地降低构件变形,在重复荷载作用下构件的裂缝宽度随重复次数N的增加而增加,构件的裂缝宽度在荷载前期增长的比较快,后期增长比较缓慢。更多还原

【Abstract】 The transportation rapid development is playing the more and more vital role in the national economy high speed development which has brought the huge challenge for the existing bridge.The repeate load causes each kind of bridge structure to appear many kinds of plant diseases,like the bridge appears the big distortion and the crack in the normal enlistment period, even endangers influence to the bridge safety performance.The domestic and foreign investigation and study thought reinforced concrete beam and the pre-stressed concrete beam fatigue failure is one of structure main destruction forms.This article makes the Ministry of Communications science and technology project the earlier period research work of“Great Span Pre-stressed concrete Beam bridge deflection Reason Analysis And Countermeasure Project”the topic three“the great span prestressed concrete beam bridge moves the load repeatedly the function effect research”.Through investigates and analyzes the domestic and foreign reinforced concrete and the pre-stressed concrete beam fatigue performance obtains many conclusions.1)This article summarized the influence concretes fatigue performance primary factor and the analysis concrete structure under redundant load function fatigue failure pattern.The scholar thought that the minimum stress level is quite sensitive under the redundant load function to the concretes resistant to compression weary performance shade, its value increases along with the minimum stress level increases.2)This article introduced that the reinforced concrete weary performance in the domestic and foreign research condition, and analysis the different scholar to calculate the light round Steel bar and deformed reinforc bar fatigue strength S-N curve characteristic.They thought that the reinforced concrete beam’s crack opening increases along with load multiplicity N increases.3)This article diagnosis prestressed concrete beam right section anti-curved fatigue performance and Induces the redundant load to the component fatigue failure shape.Through analysis contrast this article discovered that the pre-stressed muscle’s stress increases along with multiplicity N increases.This article discovered that the PPR influence is quite sensitive to the amount of deflection and component’s crack opening increases under the redundant load function along with multiplicity N increases.更多还原