钢管混凝土拱桥施工监控与拱肋吊装计算

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发布时间：2021-12-03

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钢管混凝土拱桥拱肋节段吊装施工过程是一个复杂的过程，为了保证最终的
成桥线型和受力状态满足设计要求，对其采取施工阶段的监控是十分必要的。本
文以在建的江西省吉安市白鹭钢管混凝土拱桥为施工背景，制定施工监控方案。
在稳定性满足要求的前提下，对变形、应力（变）进行双控，且以变形控制为主，
严格控制各个控制截面的挠度和拱轴线的偏移，同时兼顾考虑应力（变）的发展
情况。
目前，钢管混凝土拱桥斜拉扣挂施工方法存在索力调整次数过多、施工工期
较长等一些不足。拱肋吊装施工中扣索一次性张拉的施工方法能够克服这些不
足，具有显著的优点。而该施工方法的关键所在是准确计算拱肋吊装阶段各拱段
控制点的预抬高值和扣索索力值。本文首先建立了吊装节段拱肋控制点预抬高值
和扣索索力值计算的三维有限元优化算法，该法采用有限元方法进行仿真计算，
将优化理论引入钢管混凝土吊装施工中，采用一阶分析方法进行反复迭代计算，
最终得到各吊装节段拱肋控制点预抬高值和扣索索力值。
为便于工程应用，考虑施工拱肋为弹性体，本文建立了拱肋各吊装节段控制
点的预抬高值和扣索索力值计算的简化工程算法，该法将拱段控制点的预抬高值
分为两部分进行力学分析：拱段刚体位移引起的控制点预抬高值和拱段弹性变形
产生的控制点预抬高值，最终的拱段控制点预抬高值为这两部分之和。
简化工程算法与三维有限元优化算法结果比较表明，简化工程算法是可行的。计
算结果还表明，拱肋弹性变形引起的拱肋控制点的预抬高值达到刚体产生的预抬
高值的量级，且这种差别势必随着拱桥跨度的增大而增大，所以拱肋为刚体的假
定将会带来一定不可忽略的误差。
具体应用时，简化工程算法和三维有限元优化算法可互为补充：可先用简化
工程算法进行拱段控制点预抬高值和索力的初步计算，条件许可时，再用三维有
限元优化算法进行详细分析计算，互为验证，确保拱段控制点预抬高值和索力的
计算的正确性。
关键词：钢管混凝土拱桥，一次性张拉，优化，预抬高值，施工监控
Construction Monitoring of CFST Arch Bridges and
Calculation during Erecting Steel Tubular Arch Rib
ABSTRACT
Since rib-hoisting of concrete-filled steel tubular (CFST) arch bridges is a very
complex process, construction monitoring is necessary to satisfy the requirements of
design strength and final bridge alignment. Based on the real situation of the Bailu
bridge that is under construction in Jian City, Jiangxi Province, the detailed
construction scheme is presented. is implemented to determine the rational
construction state of a concrete-filled steel tube arch bridge. On the condition that the
stability meet the requirement, both deformation and stresses (strains) are monitored
where the section deflections of steel tubular arch ribs and the deviation of the arch
axis line are key issues. At the same time, the development of stresses (strains) is
monitored.
There are several shortages on the construction method of cable erection with
diagonal fastening and connecting, for example, it requires to adjust the cable forces
over and over again, which increases the construction time. The one-off tension
method, however, can avoid those troubles and has many advantages. About, the
crucial issue of this construction method is to accurately determine the cable forces
and the prearranged heights in each phase of erecting arch ribs. In this thesis, a 3-D
finite element based optimization method is first established to calculate the cable
forces and the prearranged heights during erecting steel tubular arch rib. In this
method, the finite element technique is used to model the structure and the
optimization theory is applied to the proposed objective function. The cable forces
and the prearranged heights in each phase of erecting arch ribs are obtained by the
first order optimization method, and the actual construction process of arch rib
erection is simulated.
In order to facilitate the practical applications, a simplified engineering method is
then proposed in this thesis to calculate the prearranged heights in each phase of
erecting arch ribs. In this method, the arch rib is considered elastic and the
prearranged height is separated two parts: the displacement due to rigid body
movement and the displacement due to elastic deformation. The final prearranged
height of the arch rib is the sum of two parts. The results of the proposed simplified
engineering method have been compared with those obtained from the 3-D finite
element based optimization method. It is demonstrated that the simplified engineering
method is feasible. It can be also observed that, and the elastic deformation has the
same quantitative level as the displacement due to rigid body movement. Therefore,
the rigid body assumption of arch ribs will result in unaccepted error. It can be
anticipated that this error will be increased with the increase in the span length of
concrete-filled steel tubular arch bridges.
In practical applications, the proposed simplified engineering method and 3-D
finite element based optimization method can be used complementally. Firstly, the
prearranged heights in each phase of erecting arch ribs can be approximately
estimated by using the simplified engineering method, and then, the results can be
verified again by the more detailed 3-D finite element based optimization method. As
a result, the correct cable forces and prearranged heights in each phase of erecting
arch ribs can be obtained.
Key words ： concrete-filled steel tubular arch brid