【作者】 杨勇；

【导师】 刘寒冰；

【作者基本信息】 吉林大学 ， 道路与铁道工程， 2006， 硕士

【摘要】 桥梁结构的耐久性是影响桥梁安全与使用的重要因素。对于变截面T梁、工字梁、箱梁等常见结构,截面形式复杂,一些部位尺寸较小且密集配筋,如梁顶板,梁底板,预应力管道间,混凝土不可避免的造成不密实导致耐久性降低,而这些问题往往为设计者所忽略。对于新建桥梁混凝土的密实度问题,尤其是新建桥梁关键部位的混凝土密实度和耐久性问题,人们研究和关心的较少,这也为桥梁的质量监督控制和使用寿命埋下了隐患。本文针对桥梁构件局部尺寸较小部位的混凝土密实度问题,进行了2片腹板宽度为14cm,2片腹板宽度为16cm的变截面预应力工字梁的静载试验和超声无损检测试验,提出密实度系数的概念,对试验梁的密实度进行定量评定,推导了工字梁的塑性系数公式,基于塑性理论给出了试验梁的开裂荷载和极限承载能力计算公式,分析了试验梁的密实度对其开裂荷载和极限承载能力的影响。同时用弹性力学原理研究了宽翼缘梁的剪力滞效应,为今后的设计以及桥梁质量控制、维修加固提供了参考。更多还原

【Abstract】 The durability of concrete has become a study hotspot in civil engineering in recent years. Since the foundation of PRC, with the rapid development of bridges, the concrete bridges of various forms and various structures have been built. However, the service life of existing bridges has not been up to the design service life. In recent years, during the detection of the established reinforced concrete or the prestressed concrete box girder bridges etc. the large structures, we can find that the concrete in particular structural positions such as the anchorage zones of prestressed reinforcement with dense reinforcement, the prestressed pipe in which the space of reinforcement or the thickness of concrete cover is small, the top and bottom flange of box girder and so on has brought great difficulty to concrete construction because of the small size and densely-packed reinforcement. Therefore, it inevitably leads to the incompactness in these positions, accordingly causes the crack or the peeling off of the concrete etc. early diseases. The early diseases not only are related to the appearance quality, but also influence the whole performance of the members, decrease the service life, seriously can also jeopardy the safety of bridge structure.The paper relies on the project of“the disease diagnose and maintenance method aiming at early deterioration in small size member of bridge”belonging to the Communications Department of Jilin province. The project is completed in the collaboration of the Transportation College of Jilin University and Transportation Science institute in Jilin province. The paper mainly studies the characteristics and mechanical performance of small size member of bridge, the problems of concrete dense degree and shear lag effect of wide flange. The static load test and supersonic nondestructive test of four pieces of prestressed I-girder with varying section are carried out in bridge structure laboratory of Jilin University. The width of web plate of two pieces beam is 14cm and another two is 16cm. The paper consists of five chapters. Of these chapters, chapters two, three and four are kernels.更多还原