【作者】 孙宏光；

【导师】 胡大琳；

【作者基本信息】 长安大学 ， 建筑与土木工程， 2011， 硕士

【摘要】 桥梁是一种复杂的空间结构,特别是预应力混凝土桥梁。在悬臂施工中,挠度的控制是施工成功与否的关键之一,而徐变引起的变形及内力重分布是挠度控制的一个难点。混凝土徐变的发生是受力混凝土对所受载荷的一种“屈服”,然而影响混凝土徐变的不仅仅是载荷,还有许多的不定因素、非线性因素,如预应力的施加及其损失等。考虑徐变后结构的挠度计算是极其复杂的,因为它包含了包括混凝土徐变在内的许多因素,而且即使计算出预拱度,在施工之前也应将计算数据并与设计值比较,从而发现问题。目前,国内外兴起修建大跨连续刚构的热潮。在大跨连续刚构的建造过程中存在一些亟待解决的问题：施工过程中应力测量值普遍偏大,成桥后期徐变挠度超过预期值过多,收缩徐变使墩顶在纵向有明显偏位等。本文从混凝土收缩徐变的机理、影响因素及计算理论方面对上述问题作了一定程度的探讨,并提出了有效的解决方法,文中总结的方法可以为大跨连续刚构桥梁施工提供参考。更多还原

【Abstract】 The bridge is a kind of complicacy spatial structure, especially PC Bridge. The deflection’s control is very important during the cantilever’s construction. But the re-distribution of strain and inner force causing by creep caused difficulty to the deflection control. The occurrence of the concrete creep can be regarded as concrete "accept defeat" for the force. However not only the force influence concrete’s creep, but also many agents such as certain agent, nonlinear, latent agent, and with some interact agents such as prepare stress’s infliction and its loss. The deflection’s computation is complicacy when considered the agents included concrete creep.so we should compare the calculation results with design data before construction to find the problem.At present, the continuous rigid frame bridges are in the upsurge of building. In the building of these bridges, there are some problems such as the stress measured is larger than the value calculated, after the bridges were completed, the creep displacements are far more than the values predicted and there are obvious lengthways displacements on the top of piers for shrinkage-creep. From the view of mechanism, infection factors and computational theories about shrinkage and creep, the article studied these problems to some extent and took the lead in putting forward the methods. These methods can provide a reference for the continuous rigid frame bridges in the future.更多还原