青藏高原连续刚构桥施工控制及温度效应研究
发布时间：2018-08-01 11:23
【摘要】：随着预应力技术的改进和桥梁施工技术的长足发展,桥梁的跨度不断增大,结构形式也日趋复杂，为了使得桥梁的线形、应力满足要求，桥梁施工过程的安全,大跨度桥梁的施工控制技术便应运而生,同时也伴随着对计算理论、混凝土收缩徐变、温度等因素对结构影响研究不断深化，桥梁建设时的控制精确度也越来越高。随着桥梁建设事业中连续梁桥广泛的应用，预应力混凝土连续刚构梁桥已经成为目前采用基础的桥梁结构，在施工过程中的施工控制的重要性就显得日益突出。本文以雅鲁藏布江三号特大桥为工程背景，采用Midas-Civil结构计算分析软件对该桥的施工过程进行模拟，计算得出本桥在各个施工阶段的挠度和内力，为大桥的监控提供理论数据，在施工的过程当中严格按照已经制定的监控方案，同时对施工各个阶段结构的受力、线形等数据进行实际量测，再通过实测值与理论值的对比、分析、寻找原因等，，对误差进行识别、预测以及最后的调整，并随着施工进度循环的过程，使桥梁结构的在施工过程中的实际状态最大程度的接近理论计算状态，不断循环上述步骤，最终确保大桥顺利合拢，并保证在施工过程中应力在控制范围内。 虽然大跨度预应力混凝土箱梁桥由于其所具有的颇多优点而应用广泛,但是随之也无法避免的出现了箱梁梁体开裂的问题，由于温度对桥梁的应力影响较大，特别是在西藏地区的温度变化快，温度较低的条件下，有必要对桥梁的抗裂能力是否满足当地气候条件进行分析预测。同时在冬季施工时，箱体内外养护温度差较大，在这种状态下便会产生拉应力，因此必须合理的控制箱体内外温度差以及拉应力值，以保证混凝土在预应力张拉之前的养护期间不开裂。本文分析温度变化对大跨度连续桥梁应力的影响，以拉日铁路雅鲁藏布江三号特大桥为例进行分析，采用Midas-Civil计算软件，计算箱型截面的大跨度桥梁成桥后，在日照作用下梁体的最大应力，分析最有可能产生裂缝的位置，进而提前采取必要的措施，采用Midas-FEA计算软件，分析在冬季施工养护期间,相对封闭箱型截面，在箱体内温度和高于外侧温度的实际状态下，分析单个浇筑块体的应力值，为冬季施工时养护温度的设定提供必要的参考依据。
[Abstract]:With the improvement of prestressed technology and the rapid development of bridge construction technology, the span of the bridge is increasing and the structure form is becoming more and more complicated. In order to make the bridge linear and stress meet the requirements, the construction process of the bridge is safe. The construction control technology of long-span bridge emerges as the times require. At the same time, the research on the influence of calculation theory, concrete shrinkage and creep, temperature and other factors on the structure is deepening, and the control accuracy of bridge construction is becoming higher and higher. With the wide application of continuous beam bridge in bridge construction, prestressed concrete continuous rigid frame beam bridge has become the bridge structure with foundation at present, and the importance of construction control in the construction process is becoming more and more prominent. In this paper, the construction process of the bridge is simulated by using Midas-Civil structure calculation and analysis software, and the deflection and internal force of the bridge in each construction stage are calculated, which provides theoretical data for the monitoring of the bridge, and takes the Yalu Zangbo River Bridge as the engineering background, and uses the software of Midas-Civil structure calculation and analysis to simulate the construction process of the bridge. In the course of construction, strictly according to the monitoring scheme that has been formulated, at the same time, the actual measurement of the structure force, line shape and other data in each stage of construction is carried out, and then through the comparison between the measured value and the theoretical value, the analysis is made to find out the reasons, etc. Identification, prediction and final adjustment of the errors, and with the progress of the construction cycle, the actual state of the bridge structure in the construction process is as close as possible to the theoretical calculation state, and the above steps are repeated. Finally, the bridge is closed smoothly and the stress is controlled during construction. Although the long-span prestressed concrete box girder bridge is widely used because of its many advantages, it is inevitable that the box girder body cracks, because the temperature has a great influence on the stress of the bridge. Especially under the conditions of rapid temperature change and low temperature in Tibet, it is necessary to analyze and predict whether the anti-cracking ability of the bridge meets the local climatic conditions. At the same time, during winter construction, the temperature difference between inside and outside of the box is large, and in this condition the tensile stress will be produced, so it is necessary to control the temperature difference and the tensile stress value of the inside and outside of the box reasonably. This ensures that the concrete does not crack during the curing period prior to the prestress tension. In this paper, the influence of temperature change on the stress of long-span continuous bridge is analyzed. Taking the Yalu Zangbo River No. 3 super bridge of the La-Ji railway as an example, the box section long-span bridge is calculated by using Midas-Civil software. Under the action of sunshine, the maximum stress of beam body is analyzed, the position where cracks are most likely to occur is analyzed, and the necessary measures are taken in advance, and the Midas-FEA calculation software is used to analyze the relative closed box section during the construction and maintenance period in winter. Under the actual condition of the temperature inside the box and the temperature higher than the outside, the stress value of a single pouring block is analyzed, which provides a necessary reference for the setting of maintenance temperature in winter construction.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U445.4;U448.23
本文编号：2157422
[Abstract]:With the improvement of prestressed technology and the rapid development of bridge construction technology, the span of the bridge is increasing and the structure form is becoming more and more complicated. In order to make the bridge linear and stress meet the requirements, the construction process of the bridge is safe. The construction control technology of long-span bridge emerges as the times require. At the same time, the research on the influence of calculation theory, concrete shrinkage and creep, temperature and other factors on the structure is deepening, and the control accuracy of bridge construction is becoming higher and higher. With the wide application of continuous beam bridge in bridge construction, prestressed concrete continuous rigid frame beam bridge has become the bridge structure with foundation at present, and the importance of construction control in the construction process is becoming more and more prominent. In this paper, the construction process of the bridge is simulated by using Midas-Civil structure calculation and analysis software, and the deflection and internal force of the bridge in each construction stage are calculated, which provides theoretical data for the monitoring of the bridge, and takes the Yalu Zangbo River Bridge as the engineering background, and uses the software of Midas-Civil structure calculation and analysis to simulate the construction process of the bridge. In the course of construction, strictly according to the monitoring scheme that has been formulated, at the same time, the actual measurement of the structure force, line shape and other data in each stage of construction is carried out, and then through the comparison between the measured value and the theoretical value, the analysis is made to find out the reasons, etc. Identification, prediction and final adjustment of the errors, and with the progress of the construction cycle, the actual state of the bridge structure in the construction process is as close as possible to the theoretical calculation state, and the above steps are repeated. Finally, the bridge is closed smoothly and the stress is controlled during construction. Although the long-span prestressed concrete box girder bridge is widely used because of its many advantages, it is inevitable that the box girder body cracks, because the temperature has a great influence on the stress of the bridge. Especially under the conditions of rapid temperature change and low temperature in Tibet, it is necessary to analyze and predict whether the anti-cracking ability of the bridge meets the local climatic conditions. At the same time, during winter construction, the temperature difference between inside and outside of the box is large, and in this condition the tensile stress will be produced, so it is necessary to control the temperature difference and the tensile stress value of the inside and outside of the box reasonably. This ensures that the concrete does not crack during the curing period prior to the prestress tension. In this paper, the influence of temperature change on the stress of long-span continuous bridge is analyzed. Taking the Yalu Zangbo River No. 3 super bridge of the La-Ji railway as an example, the box section long-span bridge is calculated by using Midas-Civil software. Under the action of sunshine, the maximum stress of beam body is analyzed, the position where cracks are most likely to occur is analyzed, and the necessary measures are taken in advance, and the Midas-FEA calculation software is used to analyze the relative closed box section during the construction and maintenance period in winter. Under the actual condition of the temperature inside the box and the temperature higher than the outside, the stress value of a single pouring block is analyzed, which provides a necessary reference for the setting of maintenance temperature in winter construction.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U445.4;U448.23
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本文编号：2157422
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