【作者】 刘晖；

【导师】 姜海波；

【作者基本信息】 广东工业大学 ， 结构工程， 2007， 硕士

【摘要】 经过长期使用的桥梁结构会由于各种原因产生各种各样的损伤，存在不同程度的病害和缺陷。上世纪七、八十年代修建的荷载等级较低桥梁，主要基于当时的交通量以及其它各方面的发展规划的。这些公路桥梁已经运营了几十年，而且仍在继续使用。随着公路交通量的日趋增大，荷载日益增加，旧危桥的加固处理已经迫在眉睫。因此，桥梁加固维修技术研究就显得尤为迫切和重要。国内许多旧桥是T型刚构桥，现在对运用体外预应力钢束加固T型刚构桥的研究比较少，探索和研究T型刚构桥加固的新技术和新方法是非常必要的。本文结合下横沥大桥体外预应力加固的实例，通过有限元理论计算分析得出以下结论：1、体外预应力钢索的布置是影响T型刚构桥加固效果的重要因素。体外预应力钢索的合理布置能够改善桥梁的受力性能和提高加固效果。本文总结了体外预应力钢索的几种常用布置方式以及每一种布置方式的优缺点。为体外预应力钢索的合理布置提供了参考。2、采用有限元分析软件桥梁博士和MIDAS／Civil对实际工程T型刚构桥有限元分析，对比桥梁加固前后承载能力的变化和主拉应力变化，认为体外预应力钢索加固T型刚构桥能提高全桥的安全储备，是一种可行、有效的方法。3、对下横沥大桥锚固区域采用有限元计算方法进行分析，研究了锚固区域的拉应力分布区域，采用锚下不同作用力工况分析对比，分析下横沥大桥锚固区域拉应力分布情况，为设计提供了依据。可采取锚固区域增加腹板、底板厚度、粘贴钢板和布置混凝土钢筋网等加固措施保证锚固结构的安全。4、作为对比研究，提出锚固块加横隔墙的组合锚固结构，有限元分析发现，该结构锚固块应力集中区域的拉应力比单锚块结构的拉应力明显减少，根据分析认为锚固块加横隔墙的组合锚固结构优于单锚固结构，建议推广应用锚固块加横隔墙的组合锚固结构于实际工程中。5、牛腿区域是上部结构中的薄弱部位。提出加厚背墙和张拉精轧螺纹钢的牛腿加固方式，通过牛腿区域加固前后有限元分析，总结出出现拉应力的大小以及拉应力集中的区域。根据分析可知，采用了加厚背墙和张拉精轧螺纹钢的牛腿加固方式后，牛腿应力集中区域的拉应力比加固前明显减少，该加固方法一种可行、有效的方法。为牛腿局部加固提供了可靠的参考。本文提出的体外预应力的加固方案和牛腿区域处理方法在下横沥大桥的加固过程中得到了运用，在实践中得到了检验。为进一步完善T型刚构桥的加固理论提供了实践参考。更多还原

【Abstract】 There is a great deal of scathe in bridge structure which is used in along time. Basing on traffic is not much in last century, it constructed lots of bridges that are not high carrying capacity. Bridges already are made use of in many times. Along with traffic is more and more increased, bridges that are built in last century can’t ensure structural safety. It is necessary to strengthen that aging bridges. It is important and exigent to investigate about strengthening old bridge structure technology.There are a larger number of old T-shaped rigid-framed bridges in our country at present. Nevertheless, further studies have not been given to the reinforcement of prestressed concrete T-rigid-frame bridges in our country. It is essential to probe and develop new methods and new technology for the reinforcement of prestressed concrete T-rigid-frame bridges.This paper introduces the analyzing theory of finite element and bridge examination in illustration of Xiahengli bridge, the paper draws the following conclusion:1、The collocation of externally prestressed tightwire is a important factor of reinforcement effect of T-rigid-frame bridge. The proper arrangement of externally prestressed tightwire can ameliorate mechanical properties of bridge and improve reinforcement effect. The paper generalizes several usual arrangement and collates merits and demerits of arrangement of externally prestressed tightwire. The proper arrangement of externally prestressed tightwire offer reference.2、The paper analyzes practical engineering by finite element analysissoftware--bridge doctor and MIDAS/Civil and compare alteration on carryingcapacity and alteration of principal tensile stress, believe reinforcement of T-rigid-frame bridge with externally prestressed tightwire enhance safety storage of bridge. The reinforcement of T-rigid-frame bridge with externally prestressed tightwire is a feasible and effective method.3、After the anchor zone of Xiahengli bridge are analyzed by finite element soft, we can distinctly realize the zone of stress density. We adopt reinforced measures to ensure the safety of anchorage. The paper compares distributed condition of drag stress by loaded different working force under anchor and offer design consideration. In order to assure the safety of anchor structure, the paper offers thickening sternum and thickening backplane and bonding steel plate and disposing concrete mat reinforcement.4、In order to compare study, the paper offers assembled anchor structure--anchorage block adding horizontal baffle. The drag stress of the zone of stressdensity assembled anchor structure is below drag stress of single anchor blockstructure. Assembled anchor structure--anchorage block adding horizontal bafflehas the grab on single anchor block structure.5、The zone of bracket is a weakness of bridge structure. The paper brings forward a reinforced way by increase the thickness of parados and draw screw thread steel. The paper summarize zone of stress density after analyzing the stress of bracket zone. After using reinforced way, the stress of bracket zone cuts down. The reinforced way is a feasible and effective method. The paper provides credible gist by evaluate reinforced effect of bracket zone.The paper brings forward the reinforced project of T-rigid-frame bridges with externally prestressing and the disposing way of bracket zone. The reinforcement way and technology described in the paper are used and verified in the successful reinforcement of Xiahengli bridge. The way and technology are useful and of great reference value to the further development of the reinforced theory of T-rigid-frame bridges with externally prestressing.更多还原