连续刚构桥施工控制
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分类号
UDC
学号20000130
湖南大学-T3J}I t学位论文
大跨预应力混凝土连续刚构桥施工控
制研究及温度效应分析
究生姓名
119光芥
养单位湖南大学土木工程学院
研培
指导老师姓名、职称
方,志教授
业桥梁与隧道工程
大跨桥
梁施工控制
专方
科究
学研
论文·提交日期
2003
7月25日摘要
施工控制是施工技术的重要组成部分,在大跨径桥梁的施工中已成为不可缺少的关键环节。由于大跨径连续刚构桥采用悬臂施工,且跨径大、连续孔数多,有效地实施施工控制对桥梁施工过程中的结构安全、确保最终大桥的顺利合拢以及成桥状态的线形和受力情况符合设计要求是必不可少的。灰色预测控制系统理论是结合连续刚构桥的施工特点,根据灰色系统理论和现代预测控制理论而提出的一个施工控制系统,它是灰色系统理论和现代预测控制理论的有机结合。本文结合白水湘江大桥工程实例,运用灰色预测控制系统,对该桥在施工过程中各施工状态进行预测控制。施工控制结果表明,将灰色预测控制系统运用于大跨径连续刚构桥的施工控制,能够确保‘施工过程中的结构安全、成桥状态的
线形以及受力情况符合设计要求。
在箱梁应力中,日照温差引起的温度应力占了较为重要的一部分,而研究混凝·土桥梁温度效应的关键在于确定结构的温度场。本文通过白水湘江大桥主桥施工阶段和合拢后成桥阶段箱梁温度场及其温度效应的24小时连续观测,对连续刚构桥温度效i应进行了详细的分析,采用新西兰规范和我国铁路规范相结合的简化温度梯度模式,计算结果与实测值较为接近。
本文最后结合白水湘江大桥高温合拢的实际情况,通过对不同合拢温度的选取,对由此年温差产生的结构内力进行了比较分析,对连续刚构桥合拢温度的合理选取进行了初步的探讨,并提出了一项有效的施工措施以保证在高温条件下合拢结构安全。
关键词:预应力混凝土连续刚构桥;施工控制;灰色预测控制系统;温
度效应Construction
Long一span
Control and Temperature
PC Continuous Rigid Frame
Effect of
Bridge
ABSTRACT
丫
户/
As the important part of modern construction technology, construction control is playing a more and more important role in the successful erection of long一span bridges. Because the balancing cantilever segmental construction method has been widely applied in the building of long一span continuous rigid frame bridge, it is necessary to execute a construction control effectively to ensure the structural safety, successful closure of a
span and the ideal alignment of superstructure during and after erection of the bridge. In this thesis, a grey predictive control system for one construction control of long span pc continuous rigid frame bridge has been developed from the grey system theory and the modern predickive control
theory, and the system has been applied on the construction’control of
Baishui Bridge across Xiangjiang River in Qiyang that is a PC continuous
rigid frame bridge with two main spans of 120 meters to predict and control
all construction states. It has been proved that the application of Grey
predictive control system can ensure construction safety, make ideal
alignment of superstructure and the internal force of Baishui Bridge after
closing-join to meet the design requirement successfully.
The stress caused by sunshine is an important part of reaction of PC box
girder and it is crucial to have a certain temperature field to determine the
temperature effect of the PC box girder bridge. Based on the 24 hours
continuous observation on the temperature filed and the corresponding
effects of the Baishui Bridge during and after its construction, a simplified
temperature gradients pattern is put forward, the effect of temperature
difference on the PC continuous rigid frame bridge is thoroughly analyzed
on the base of the temperature gradient, and the calculating results agree
well with measured ones, which demonstrate the temperature gradient
0model presented here is feasible.
When Baishui Bridge is closed join at high air temperature, the internal
forces in the structure caused by the higher temperature difference are
analyzed, and a reasonable measurement has been put forward to ensure the
bridge closed successfully in the higher air temperature.
Keywords:PC continuous rigid frame bridge; Construction control;Grey
predictive control system; Temperature effect土箱梁桥的温度应力进行了深入的研究,取得了一系列重要成果。刘兴
法在文献〔29」中,系统论述了预应力混凝土箱梁桥的温度分布与温度应
力问题,建立了预应力混凝土箱梁桥的控制温度荷载及相应的温度应力
计算方法。他将箱梁桥温度场简化为二维温度场,按竖向和横向的一维
温度场计算再进行简单的叠加来计算温度应力,同时考虑了横向温度荷
载。该成果已被纳入铁路桥涵设计规范中〔12]。刘兴法在文献[[30〕中系统
论述了混凝土工程结构在自然环境中温度变化作用下的计算理论与方
法,对混凝土结构日照温度荷载、骤然降温荷载及相应的温度应力均进