Analysis on the Influence of Ambient Temperature on Integral Lifting Construction Technology for High-Rise Connected Structure
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摘要: 施工过程是保证结构使用性能可靠、质量达标的重要阶段,并且伴随社会经济的发展,对施工质量要求也逐渐提高。环境温度是影响施工精度、保证施工质量的关键因素,其在铁路、桥梁等大跨超长结构中广受关注,但在建筑结构的施工阶段研究较少。随着建筑结构设计日益复杂,体量日益增大,环境温度对施工的影响也开始显现。针对高层连体结构中常用的整体提升施工技术,探讨了环境温度在连体拼装以及连体提升这两个重要施工阶段的影响:1)拼装阶段,连体结构受到下部拼装胎架、支撑架等措施的约束,使得其在温度作用下产生附加内力及变形,下部措施结构分别按极小水平约束与刚接两个极端条件考虑。2)提升阶段,连体结构无水平约束,水平方向可自由变形,因而会显著影响连体在高空与塔楼结构对接精度的影响。为此提出将温度变形与施工变形进行叠加,从而综合考虑温度对连体提升精度的影响。分析中,以有限元模拟为基础,通过线性拟合获取关键对接点变形与温度的关系,进一步计算温度与对接错口量关系,从而得到错口量最小时的温度差,以此温差指导提升施工的时间安排。最后,以杭州云门钢结构工程为例,分析了环境温度在该项目中的影响。拼装阶段若不考虑胎架的水平约束,环境温度对结构的附加应力小。反之则会引起较大的附加应力,甚至超过钢材的屈服应力,该计算结果是基于极端情况下的计算,即温差变化大,约束强,实际工程条件出现的概率低。因此,建议应力分析中应根据工程项目的真实环境、措施使用等情况,选择合理的温差和边界条件进行分析,从而判断温差对结构附加应力的影响。对于云门钢结构的提升阶段,分析结果表明,当提升时的环境温度低于拼装时27.6℃时,连体与塔楼错口量最低。由于该温差太大,不可能在真实环境中出现,由此可知,随着环境温度的降低,提升时的连体与塔楼错口量降低,从而有利于施工精度保证,因此建议应尽可能选择在清晨或傍晚进行合龙对接。Abstract: The construction process is an important stage to ensure the reliable performance of the structure and to meet the quality standards. With the development of social economy, the requirements for construction quality are gradually improved. Ambient temperature is the key factor which affects the construction accuracy and maintains the construction quality. It is widely concerned in long-span structures judge the influence of temperature difference on the additional stress of the structure. For the lifting stage of Yunmen steel structure, the analysis results show that when the ambient temperature at the time of lifting is 27. 6 ℃ lower than during assembly, the amount of misalignment between the connected structure and the tower is the lowest. The temperature difference is too large to occur in the real environment. It can be seen that with the decrease of the ambient temperature, the amount of misalignment between the connected structure and the tower during lifting decreases, which is conducive to the construction accuracy assurance. Therefore, it is recommended that the docking should be carried out early in the morning or late afternoon as much as possible. such as railways and bridges, but there is less research in the construction stage of building structures. With the increasing complexity of building structure design and the increasing structure dimension, the impact of ambient temperature on construction begins to appear. Therefore, based on the integral lifting technology, which is widely applied in high-rise connected structures, this paper discusses the influence of ambient temperature on the two important construction process, assembling and lifting stage. In the assembly stage, the connected structure is constrained by the tire frame and support frame, so that it produces additional internal forces and deformation under the action of temperature. The structure of the supporting measures are considered under two extreme conditions: minimal horizontal constraint and rigid connection. In the lifting stage, the connected structure has no horizontal constraint and can be freely deformed in the horizontal direction, which will significantly affect the influence of the connected structure docking accuracy with the tower structure at high altitude. In this paper, the temperature deformation and construction deformation are superimposed and it is proposed to comprehensively consider the influence of the temperature deformation and the construction deformation on the lifting accuracy of connected structure. In the specific analysis, based on the finite element simulation, the relationship between the deformation of the key linking point and the temperature is obtained by linear fitting. The relationship between the temperature and the amount of docking is further calculated, so as to obtain the temperature difference with the smallest misunderstanding. Therefor time schedule of the lifting construction with this temperature difference could be guided. After that, taking Hangzhou Yunmen steel structure project as an example, the influence of ambient temperature in the project was analyzed. If the horizontal constraint of the tire frame is not considered in the assembly stage, the additional stress of the ambient temperature on the structure is small. On the contrary, it will cause greater additional stress, even more than the yield stress of the steel. The calculation result is based on the calculation in extreme cases, which means the temperature difference changes greatly and the constraint is strong. The probability of actual engineering conditions is low. Therefore, it is suggested that in the stress analysis, reasonable temperature difference and boundary conditions should be selected for analysis according to the real environment of the project and the use of measures, so as to
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Key words:
- ambient temperature /
- integral lifting /
- high-rise connected structure /
- assembly stage /
- lifting stage
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