【作者】 陈玮；

【导师】 涂凌； 周志祥；

【作者基本信息】 重庆交通学院 ， 桥梁与隧道工程， 2004， 硕士

【摘要】 预应力混凝土桥梁是国内外最常用的桥梁结构,我国近年来修建了大量的预应力混凝土公路桥梁,在交通建设取得不小成就的同时,一些预应力混凝土桥梁也出现开裂现象。本文针对重庆境内30米跨径的后张预应力混凝土空心板在施工和使用阶段中在梁底面出现沿预应力钢束纵向的裂缝,开展了如下研究工作:1.通过对试验梁从施工到使用阶段在静力循环荷载作用下的受力性能、开裂前后的受力行为、裂缝发展形式以及破坏形态的力学行为进行分析和研究,指出设计施工偏差是导致在试验梁在施工和使用阶段出现许多异常现象的主要原因;2.通过对试验梁在循环荷载作用下的各次开裂弯矩实测数据的分析,提出了考虑循环荷载作用次数的再次开裂弯矩的计算公式,比较表明,该公式与试验值吻合较好;3.通过对理想无损状态和有纵向裂缝状态在施工和使用阶段受力性能的数值分析,论证了纵向裂缝的存在使得预应力混凝土空心板的抗裂性降低;4.利用ANSYS中Fatigue模块进行疲劳分析,结果表明,纵向裂缝的存在使梁的疲劳寿命由200万次降低为18.34万次;5.依据对带有纵向裂缝的空心板的试验研究和理论分析,归纳总结纵向裂缝产生的原因,为以后同类预应力混凝土桥梁的设计和施工提供了有价值的参考。更多还原

【Abstract】 A large number of prestressed concrete bridges, ’which are the most popular bridge structures, around the world have been built in our country. However, with the rapid development of the traffic construction, the cracks of the prestressed concrete bridge appear as well. The thesis focuses on the post-tensioned prestressed void slab bridge, where the longitudinal crack a long the prestressed wire strand at the bottom of the girder are found during the operation, with 30m span in Chongqing and does the following research:1. Based on the analysis and the research of the mechanic performance, and the development of the cracks of the test beam under the dead and cycle load, the deviation between the design and the construction is pointed out as the main reason of the abnormal phenomenon of the test bean during its phases of construction and use.2. According to the analysis of the cracking moment of the test girder under the cycle load, the formation, used to calculate the number of second cracking moment considering the effect of the cycle load, is provided. It has been proved satisfied to be consistent with test results.3. On the basis of the numerical analysis of the mechanic performance at the phases of construction and use, the shear resistance of the prestressed concrete voided slab with longitudinal cracks is lower, compared to the ideal situation without damage.4. With the help of the fatigue analysis in the Fatigue model of ANSYS, the results show the fatigue life of the girder is decreased from 2 millions to 180.34 thousands because of the existence of the longitudinal cracks.5. Based on the test research and the theory analysis, the reasons why the cracks appear are summarized, which can be a valuable references to the design and the construction of the similar prestressed concrete bridge.更多还原