【作者】 涂杨志；

【导师】 张开银；

【作者基本信息】 武汉理工大学 ， 结构工程， 2003， 硕士

【摘要】 随着我国高速公路建设的蓬勃发展，桥梁建设进入了前所未有的高潮时期，大跨度预应力混凝土桥型以其独特的优势被广泛采用。由于桥梁跨度的不断增大，对大跨度预应力混凝土桥梁的设计、施工、材料及设备等要求亦不断提高。目前，在部分已建成运营的大跨度预应力混凝土连续梁桥的不同部位出现了不同程度的开裂现象，多数是由于施工时对结构预应力损失估计不足所造成的。特大型桥梁的结构安全可靠性已成为当今社会普遍关注的问题。 对大跨度预应力混凝土桥梁而言，由于预应力损失的影响，结构的实际应力与设计应力很难完全吻合，即计算应力不能很好地反映结构的实际应力状态，从而留下安全隐患，严重影响了工程建设质量。与短索的预应力损失相比，长索预应力损失随着索长度的增加，成非线性增长。究其原因，与施工工艺密切相关，主要是波纹管逐节段拼接定位、平直度误差及局部漏浆等所致。因此，在大跨度混凝土结构桥梁设计时，对结构施工中的预应力损失要有足够的估计，有可能根据实际施工情况，合理地配置预应力筋。只有准确地估计长索预应力损失大小，才能合理地进行结构预应力设计，保证预应力混凝土结构的承载能力，确保桥梁结构的安全性、可靠性、经济性和使用寿命。如何合理地给出摩阻损失系数或找出其变化规律，成为长索预应力损失估计的研究重点。 本文从理论上对预应力混凝土结构预应力损失做了全面地分析，结合襄樊汉江四桥建设工程，对桥梁预应力钢索的预应力摩阻损失进行了理论分析和试验研究。首先运用桥梁结构分析专用软件GQJS对预应力混凝土连续梁桥进行结构计算，得到了各施工工况下混凝土箱梁的挠度和截面应力；然后给出了识别引起结构预应力损失的孔道偏差系数k的两种方法(间接法和直接法)。通过对测得的预应力索沿程应力和混凝土箱梁截面应力数据的分析处理，得到了合理的预应力孔道摩擦偏差系数及预应力摩阻损失规律。其结果对该桥的施工控制，提供了可靠的数据依据，确保了施工质量。同时，对大跨度预应力混凝土桥梁设计与施工具有指导意义。更多还原

【Abstract】 With the rapid development of highways in our country, bridge construction has come in the upsurge period hitherto unknown, the long span prestressed concrete bridge is used widely for its advantage. Because the span of the bridge becomes longer and longer, the request of designing, construction, material and equipments should be elevated. At present, crack phenomenon always appears in long span prestressed concrete continuous beam bridges used, the reason of which is that the structure prestressed loss is estimated lower. The security and dependability of the extra long bridge structure have become the general concern question of the society in these days.Because of the influence of the prestressed loss, the real stress doesn’t coincide with the designed stress, that is to say, the calculated stress doesn’t display the condition of the real structure stress properly, and thereby the undiscovered danger leads to the quality of the engineering construction. Compared with the prestressed loss in the short steel rope, the prestressed loss in the long steel rope nonlinearly increases with length of the steel rope. It is apparent that the error of piecing and locating the corrugated pipe and the error of level and upright and leaking in the part lead to increase of friction loss. So in the process of designing the long span concrete bridge, the estimation to prestressed loss should be proper. Only to do mis, the value of prestressed force is designed suitable, the capability that the prestressed concrete structure bears weight, security, and dependability, economy and service life of the structure can be convinced. How to give out the friction factor and the regular pattern is the importance of researching the prestressed loss in the long steel rope.In this article the prestessed loss in the prestressed concrete structure will completely be analyzed in the theory. Combining with the fourth-Hanjiang bridge of Xiang-Shi Freeway in Hubei Province, the prestressed friction loss of the prestressed steel rope is analyzed ideally and researched experimentally. At first, the soft of bridge structure, GQJS, is used to calculate the structure of prestressed concrete continuous beam bridge and the deformation and stress of the concrete box beam are given out; then by measuring and analyzing the datum of the stress in the prestressed steel rope and the stress of section in the concrete box beam, this article presents two ways to identify the reasonable friction deviation factor k between longitudinal prestressed tendons and the wall of duct (indirectly and directly), and discover the regular pattern of prestressed friction loss. The conclusion may provide reliable datum for structure construction controlling and guarantee the quality of construction. At the same time, the conclusion has guide significance for designing and constructing long span prestressed concrete bridges.更多还原