【作者】 何军；

【导师】 符锌砂； 戴晓鹏；

【作者基本信息】 华南理工大学 ， 交通运输工程（专业学位）， 2017， 硕士

【摘要】 本文以广州市某桥为工程背景,结合该桥从2006年至2015年的线形观测数据,对混凝土收缩徐变计算模式进行综合评价。依托工程背景,建立其有限元模型,对跨中顶推、边跨压重、边支座主动沉降、张拉备用钢束等挠度控制措施进行分析计算;提出体外预应力技术的思路控制主梁长期挠度,并进行试设计。本文的主要工作和结论为:(1)在该桥桥面上设置主梁线形观测点,定期观测主梁线形变化,依据理论计算及实测数据,得到主梁跨中挠度随环境温度变化关系。(2)主梁成桥运营后对主梁线形进行了8次观测,得到线形随时间变化关系,考虑温度因素,根据实测主梁跨中挠度随环境温度变化关系换算主梁线形,得到截至2015年主梁跨中累计挠度值。(3)使用MIDAS/CIVIL建立桥梁杆系模型,根据设计图纸划分施工阶段,选取计算参数及各阶段荷载。(4)综合已有研究成果,对预应力损失、混凝土收缩徐变原因进行分析,结合工程实例,对各计算方法进行参数分析,选择合适计算参数。(5)对混凝土收缩徐变机理进行分析,列举出多种混凝土收缩徐变计算方法,结合桥梁长期挠度实测数据对各计算模式进行分析发现《公路钢筋混凝土及预应力混凝土桥涵设计规范》(JTG D62-2004)所计算模式与实测值吻合较好。(6)对荷载平衡法、顶推法、压重法、支座主动沉降法、张拉备用钢束法、体外预应力法进行分析计算选择合适地挠度控制方法。更多还原

【Abstract】 A bridge in Guang Zhou was taken as the actual background combined with elevation observation data from 2006 to open to 2015 in this paper to conduct a comprehensive evaluation of the concrete shrinkage and creep calculation model.Taking the bridge as the engineering background,the construction control measures such as: push load in the middle span,side span pressure,active settlement of side support of continuous rigid frame bridge were analyzed and calculated.According to the finite element model of this bridge,control effect of long-term deflection of bridge girder was analyzed,the initial design of long-term deflection method with external prestressed treatment was carried out.The main work and conclusions of this paper were listed as follows:(1)Taking a bridge in Guang Zhou as the engineering background,the long-term observation points of the main girder was set and the elevation of the main girder is observed regularly and the relationship between the middle span and ambient temperature was established by theoretical calculation and measured data.(2)The relationship between elevation curve and time was obtained by 8 observations,consider the temperature factor the main girder span deflection was converted by ambient temperature and the cumulative deflection value of the main beam is measured by the time of 2015.(3)The finite element model of the bridge was built by MIDAS / CIVIL and the construction phase was divided according to the design drawings the calculation parameters and calculate the load value of each stage were selected.(4)Based on the analysis of existing research results,the causes of prestress loss,shrinkage and creep of concrete are analyzed.Combined with the bridge,the parameters of the calculation method were analyzed and the appropriate calculation parameters were selected.(5)The shrinkage and creep mechanism of concrete were analyzed,and various kinds of the calculation methods of shrinkage and creep of precast concrete were listed.Combined with the measured data of long-term deflection of the bridge,the calculation methods are analyzed.According to the analysis results,JTG D62-2004 specification calculation model was the most close to the measured value.(6)The method of load balance method,push method,pressure reduction method,bearing active sedimentation method,tension reserve steel bars method and external prestress method are carried out and the appropriate deflection control method was selected by analysis and calculation.更多还原