高层混凝土框架—核心筒结构施工期安全性研究

发布时间：2018-08-08 16:19

【摘要】：据不完全统计资料表明,至少有三分之二以上的工程倒塌安全事故发生在施工阶段。要降低高层建筑混凝土结构施工期发生安全事故的概率,形成高层建筑混凝土结构施工期的安全控制体系,就必须建立在对高层建筑混凝土结构施工期性能研究的基础上。混凝土框架-核心筒结构作为一种重要的高层和超高层建筑结构形式近年来在我国得到越来越广泛的应用,同时伴随着施工期间安全事故的不断发生也给我国的工程界和学术界带来了极大的挑战。由于高层建筑混凝土结构施工期材料性能不稳定、施工荷载多而复杂、受力大而多变,具有混凝土结构性能随时间变化的时变特性,因此对高层建筑混凝土结构施工期的性能研究就显得更为复杂和困难。围绕施工期高层建筑混凝土结构的时变特性,本文对施工期高层建筑混凝土材料时变性能、混凝土结构与临时模板支撑体系的共同作用机理、高层建筑混凝土框架-核心筒结构施工全过程竖向构件受荷实测研究以及高层混凝土结构可靠度开展试验研究和理论分析。本文的主要内容包括:针对目前高层建筑混凝土的强度特点,对混凝土材料的抗压强度和弹性模量随标准养护龄期变化的时变特性进行了试验研究。通过对试验研究建立了混凝土抗压强度和弹性模量随龄期增长的函数关系并且采用非线性最小二乘算法给出了拟合方程的参数。根据高层建筑结构常用的HPC的材料特性,对不同强度等级、不同水胶比、不同粉煤灰掺入量和不同外加剂掺量混凝土材料的抗压强度和弹性模量随标准养护龄期变化的时变特性进行了试验研究。通过试验总结得到了水胶比、外加剂和粉煤灰掺入量对HPC时变性能的影响规律。以重庆中华新城工程为背景,针对现场支撑层数不同的实际施工情况,采用有限元软件建立的仿真计算模型模拟分析了时变结构体系的结构性能,并通过模拟分析结果给出了施工建议和控制措施。在实验室制作了2个两层单跨钢筋混凝土框架试验模型,在不同龄期对模型框架加载,分析施工周期、混凝土龄期等因素对施工期混凝土结构与临时模板支撑体系共同作用影响的试验研究,得到了当施加小于开裂荷载的荷载作用时施工期混凝土结构与临时模板支撑系统的共同作用规律。以中山国际金融中心工程为背景,采用合理的测试手段,针对高层建筑混凝土框架-核心筒结构不同强度等级混凝土竖向构件施工过程中的受荷变形进行现场监测,并对施工期高层建筑混凝土框架-核心筒结构竖向构件受荷变形的发展规律进行了归纳总结。以两层框架模型试验和重庆中华新城工程典型结构为背景,基于结构可靠性分析的动态模型,结合施工期混凝土结构特点、结构构件抗力及荷载效应的概率模型,运用蒙特卡罗随机算法,提出了以混凝土开裂和楼板冲切破坏为失效模式进行施工期混凝土结构的可靠度分析方法,并针对计算结果提出了施工期混凝土结构的施工建议。
[Abstract]:According to incomplete statistical data, at least 2/3 of the project collapse safety accidents occur in the construction stage. To reduce the probability of safety accidents in the construction period of the high-rise concrete structure and to form the safety control system for the construction period of the high-rise building concrete structure, it must be built on the construction of the concrete structure of the high-rise building. The concrete frame core tube structure, as an important high-rise and super high rise building structure, has been widely used in our country in recent years. At the same time, the continuous occurrence of safety accidents in construction has brought great challenges to the engineering and academic circles of our country. In the construction period of concrete, the material performance is unstable, the construction load is more complex and the force is large and changeable. It has the time-varying characteristics of the concrete structure performance with time. Therefore, it is more complicated and difficult to study the performance of the concrete structure during the construction period. In this paper, the time-varying performance of concrete materials in the construction period, the joint action mechanism of the concrete structure and the temporary formwork support system, the measured study on the loading of the vertical member in the whole process of the construction of the concrete frame core tube structure in the high building, as well as the experimental research and theoretical analysis of the reliability of the high-rise concrete structure, and the theoretical analysis in this paper. In view of the strength characteristics of the present high building concrete, the compressive strength and modulus of the concrete material are tested with the time-varying characteristics of the standard curing age. The function of the compressive strength and modulus of concrete with the increase of the age of the concrete is established and the nonlinear minimum 2 is adopted. The parameters of the fitting equation are given by the multiplicative algorithm. According to the material characteristics of the HPC used in the high-rise building structure, the experimental study on the time-varying characteristics of the compressive strength and modulus of concrete with different strength grade, different water binder ratio, different fly ash content and different admixture content of concrete with the standard curing age is carried out. The effect of water glue ratio, admixture and fly ash content on the time-varying performance of HPC is summarized. Based on the construction of Chongqing Zhonghua new town project, the structure performance of the time-varying structure system is simulated and analyzed by the simulation model established by finite element software. The construction proposal and control measures are given. 2 test models of two storey single span reinforced concrete frame are made in the laboratory. The experimental study on the effects of loading of the model frame on the model frame, the construction period, the age of concrete and other factors on the common effect of the concrete structure and the temporary formwork support system during the construction period is studied. The joint action law of concrete structure and temporary formwork support system during the construction period is less than the load of cracking load. Taking the Zhongshan international financial center project as the background, using reasonable test means, the loading deformation of the concrete frame core tube structure of the concrete frame core tube structure with different strength grade of the concrete vertical member during the construction process. The field monitoring is carried out, and the development law of the bearing deformation of the vertical member of the concrete frame core tube structure in the construction period is summarized. The dynamic model based on the structural reliability analysis is based on the two storey frame model test and the typical structure of the Chongqing Zhonghua new town project, and the concrete structure characteristics of the construction period are combined. By using the Monte Carlo stochastic algorithm, the reliability analysis method of concrete structure during construction period is put forward by Monte Carlo stochastic algorithm, and the construction proposal of concrete structure during construction period is put forward according to the calculation results.
【学位授予单位】：重庆大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TU973.17;TU974

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