【作者】 张博；

【导师】 何沛祥；

【作者基本信息】 合肥工业大学 ， 结构工程， 2010， 硕士

【摘要】 防治火灾是长期而艰巨的任务。预应力钢筋混凝土结构是现代工程结构中一种新的结构形式,所以关于其温度场的研究也越来越有意义。在试验室中模拟难度较大,人力、财力消耗较多,危险性也比较高。本文针对预应力钢筋混凝土板在标准升温曲线作用下的温度-应力场进行有限元数值模拟研究。主要工作如下:(1)对国内外关于钢筋及混凝土热力学参数随温度变化的规律进行了归纳总结;以热传导基本方程为依据,详细介绍了高温条件下截面温度场的有限元方程推导过程,为温度场的数值模拟打下了理论基础。(2)通过前面数据确定了对流换热系数、辐射换热发射率系数、混凝土导热系数及比热的取值。然后进行预应力钢筋混凝土板的温度场分析和应力应变的数值模拟。按标准升温曲线模拟温度,通过应用ANSYS软件实现对预应力混凝土单向简支板的温度变化全过程分析。绘制了板截面上距受火面不同高度的升温曲线。再将有限元模拟值与试验结果比较,分析两者误差原因,及有限元模拟值的合理性。(3)火灾中,建筑物的构件除了要承受正常使用的荷载外,还承受温度应力。由于边界条件的限制,温度应力造成预应力混凝土构件发生变形,再内部产生较大内力。本文先通过数值计算方法介绍了板温度应力和挠曲微分方程。然后用有限元软件模拟温度场中预应力钢筋混凝土简支板的温度应力、板的变形、板的应变等。同时,分别对自定义预应力混凝土简支板在标准升温曲线下的变形进行了数值分析。经过计算可得,在正常荷载作用下预应力混凝土板的耐火性较好。更多还原

【Abstract】 It is a long term and arduous task to prevent and control fire. As reinforced prestressed concrete structure is a new kind of modern structural styles in structure engineering , its investigation in temperature field has become more and more significant . It is not only difficult to situate the fire field in the laboratory but also in a considerable risk as well as human and financial resources consuming. This thesis aims to demonstrate finite element numerical simulation study about temperature-stress field of reinforced prestressed concrete slabs under permanent loads when it is in high-temperature conditions .The primary tasks are as follows:(1)The laws of parameters about reinforcing steel and concrete along with temperature at home and abroad are summarized .The finite equations of section temperature field under fire are derived on the basis of the heat conduction fundamental equations in detail .The theoretical foundations of the temperature field software are laid firmly.(2)Based on the last data, the values of convection heat transfer coefficient, radiation emissivity coefficient, thermal conductivity and specific heat of concrete are determinate by a trial and error procedure. After deriving suitable parameters,the temperature field of reinforced prestressed concrete slabs has been analyzed : in addition to that,the ultimate be bearing capacity has been calculated. By simulating the scene of a fire temperature according the ISO standard temperature elevation curve. Temperature change analysis of prestressed concrete simple slab subjected to fire is carried out by using of ANSYS software. Different temperature curves that are apart from the fire surface have been presented in this thesis. Then error analysis has been done by comparing the finite element simulation value with the experimental observed value. The rationality of the finite element simulation value has been analyzed.(3)When the fire,besides its ability to sustain normal use loads,each component of building is also required to sustain extra temperature stress. As a result of border restrictions,the whole reinforced prestressed concrete structures will be deformed by the temperature stress in addition to that, a great internal force will be produced. In this thesis,temperature stress and differential deflection equation of the thin slab interior will be derived from numerical calculation; the finite element software has been used to simulated temperature stress and the deformation and strain of thin slab interior by the non-linear theory. Then besides, the nonlinear analyses were also done on the deflections of the prestressed concrete bonded simply supported slab respectively in ISO standard temperature rise conditions, and the results show that the prestressed concrete bonded simply supported slab has a good fire resistance under the normal design load level.更多还原