【作者】 管仲国；

【导师】 李建中；

【作者基本信息】 同济大学 ， 桥梁与隧道工程， 2006， 博士

【摘要】 采用适当的加固措施对在役混凝土桥梁进行加固是解决桥梁结构通行能力不断下降与通行需求持续增长之间矛盾的有效途径，符合我国公路交通的发展战略。本文在总结混凝土桥梁加固技术发展的基础上，主要进行了以下几方面工作： 1．在查阅大量国内外文献的基础上，对混凝土桥梁加固技术的发展现状进行了系统的回顾和总结。 2．提出梯形混凝土非等参单元法改善截面数值积分算法，通过采用材料非线性本构关系衍生函数的解析解，来避免传统方法中的大量数值积分运算。 3．研究了加固后截面相对受压区高度以及恒载初应变对外贴FRP加固RC、PC受弯构件加固效率的影响。提出以FRP片材等效折减系数来考虑PC受弯构件加固后极限状态预应力钢筋效能降低的影响，并结合理论推导和参数分析讨论了系数的取值方法。在此基础上，给出RC、PC构件外贴FRP加固求解FRP用量的显式计算方法。 4．提出适用于具有复杂荷载-变形关系的预应力混凝土、粘贴加固后的钢筋混凝土、预应力混凝土构件的延性指标，该指标可以将不同体系之间的延性评价标准统一起来。 5．加固后构件的延性能力宜满足最低延性能力要求。本文提出以界限延性相对受压区高度来保证加固后构件的延性能力，并给出几种常用的粘贴FRP加固法的界限延性相对受压区高度的建议取值。在此基础上，研究了构件最大可加固空间与截面相对受压区高度、界限延性相对受压区高度之间的关系。更多还原

【Abstract】 To rehabilitate or strengthen bridges in service is a feasible way to deal with the contradiction between the decreasing bearing capacity and the increasing demand, which is consonant with the development strategy of traffic infrastructure in our country. This paper gives a study on the strengthening issue of concrete bridges, and the main contents are as follows:1. Based on comprehensive reading of related literature home and abroad, researches on bridges strengthening technology are reviewed.2. A trapezoidal non-isoparametric element is presented to promote the algorithm of numerical integration method, which can avoid the plenty integration calculations in traditional way through the analytic solution given by derivative constitution functions.3. The effects of relative compression height and preexist strain on strengthening efficiency are studied. A equivalent reduction coefficient is suggested to consider the decaying effects of prestress strands after strengthening, and the proper value is estimated through theoretic deduction and parameter analysis. Then an explicit method for calculating FRP volume of RC, PC girder strengthened with externally boned FRP is present.4. A new ductility index is proposed for members with complicated load-deformation curves such as PC girder, strengthened RC or PC girder with externally bonded FRP system, and the index can give the same evaluation crierion for those different systems.5. Strengthened members should be ductile. In this paper, a limit relative height is put forward to ensure the essential ductility, and the proper values are suggested for several usual strengthening cases such as externally bonded FRP sheet or plate for RC, PC girders. Moreover, the relationships of feasible capacity improvement verse relative compression height and the limit relative height for ductility are studied.更多还原