主跨215 m连续刚构桥施工监控关键技术研究

邱云

摘 要：为做好主跨215 m连续刚构桥的施工监控工作，采用远程无线定时自动采集系统，再结合工况应力增量累计法，实现了应力实测值与理论值较好的相符。同时采用正装计算法，用Midas Civil软件建立仿真计算模型，进行了参数敏感性分析，分析结果表明：施工监控采用的仿真计算模型应按实测容重进行施工过程累计挠度的计算;在混凝土龄期满7天再进行预应力张拉，有利于避免大跨径连续刚构桥的长期下挠。结合仿真计算和实测结果，温度修正的理论最大值可采用JTG D60—2015给出的日照温差分布模式，温度基数取水泥混凝土铺装对应的基数进行仿真计算。采用的立模标高確定方式和预拱度设置方式可供同类工程参考。

关键词：连续刚构桥;施工监控;预拱度;温度梯度;敏感性分析

中图分类号：U448.23      文献标识码：A       文章编号：1003-5168（2021）24-0065-05

Research on Construction Monitor and Control Technology of Continuous Rigid Frame Bridge with Main Span of 215 Meter

QIU Yun

（Foshan Road and Bridge Supervision Station Co.，Ltd.， Foshan Guangdong 528041）

Abstract：In order to achieve the construction monitor and control the continuous rigid frame bridge with main Span of 215 meter， the remote wireless automatic timing acquisition system combined with the working condition of stress increment cumulative method was adopted， and realized the stress measured values are better in conformity with the theoretical value. At the same time， the formal calculation method and Midas Civil software were used to establish a simulation calculation model， and the sensitivity analysis of parameters was carried out. The results show that the simulation calculation model used in construction monitoring should calculate the accumulated deflection in the construction process according to the measured bulk density， and the concrete should be prestressed until it has reached 7 days， the purpose of which is to avoid long-term deflection of long-span continuous rigid frame bridge. According to the simulation calculation and measured results， the theoretical maximum value of temperature correction can be obtained by using the distribution mode of temperature difference given by JTG D60-2015， and the temperature base corresponding to the cement concrete pavement can be used for simulation calculation. The determination method of the elevation and the setting method of the pre-arch can be used as reference for similar projects.

Keywords：continuous rigid frame bridge; construction monitoring and control; camber;temperature gradient; sensitivity analysis

为了确保采用挂篮悬臂浇筑的连续刚构桥施工过程中结构的安全和线形偏差等满足规范[1]要求，要进行施工监控。施工过程中，对结构安全和线形偏差产生影响的因素很多，这些影响因素的分析和控制方法引起了国内外学者和桥梁工程师的关注和重视。温度梯度作用对施工监控的标高观测存在较大影响，但由于地域差异等因素[2-8]，已有标准[9]没有给出温度梯度对结构变形测试的修正公式。跨径在80 m及以上的挂篮施工梁桥的成桥预拱度的设置一般按余弦曲线分配，但最大预拱度的取值还是没有形成较一致的标准[9，10]。应力测试误差的消除方法[11]，挠度分析和仿真模型参数调整方法[12]也有研究，也是未形成较一致的标准。本文在已有研究的基础上，结合实际工程，针对温度梯度对结构变形的影响、成桥预拱度的设置与应力测试误差消除的方法进行研究，为后续工程和研究提供参考。