围护结构保温对砌体房屋温度作用的影响与墙体裂缝控制措施

发布时间：2018-03-25 05:31

本文选题：温度场　切入点：温度作用　出处：《长沙理工大学》2014年硕士论文

【摘要】：砌体结构房屋的顶层墙体和屋盖之间的体积变形差受到相互约束引起墙体产生内力,当内力超过墙体破坏强度时会导致墙体开裂,从而影响结构的正常使用。体积变形主要由温度作用和砌体墙干燥收缩组成。首先,考虑房屋所处地区、朝向、颜色、保温形式等影响因素,利用傅里叶级数,将空气综合温度简化成谐波热作用和稳态温度作用叠加,采取变量分离法得到多层墙在谐波热作用下温度场的解析解求解方法。其次,将解析解所求的年温差和日温差进行组合,得到围护结构的温度荷载,再通过与砌体墙干燥收缩变形所产生的等效温度荷载组合,计算出墙体最大体积变形作用。第三,利用排架比拟法和有限元分析法,求出顶层墙体的内力,得到了剪力在墙体中的分布规律。排架法计算结果发现,墙体中剪力由中间窗间墙向最外端窗间墙呈递增的规律；有限元分析法计算结果表明,外端第二个窗间墙剪力最大,除最外端窗间墙受轴向拉力外,其于窗间墙受轴向压力。通过对内力值的数学回归,推导出砌体房屋顶层墙的温度作用简化计算公式。对比两种计算方法的优劣,有限元法求出的内力大小及分布情况的准确性更高。最后,利用温度内力简化计算公式和砌体结构抗剪强度公式,计算出顶层墙在不同工况作用下的最大伸缩缝间距和不设伸缩缝情况下的墙体最小配筋率或是否设置构造柱,据此提出了“放”和“抗”的裂缝控制措施。
[Abstract]:The volume deformation difference between the top floor wall and the roof of the masonry structure house is constrained mutually, which will cause the wall to crack when the internal force exceeds the failure strength of the wall. The volume deformation is mainly composed of temperature and dry shrinkage of masonry wall. First of all, considering the area, orientation, color, insulation form and other influencing factors of the building, the Fourier series is used. The synthetic air temperature is simplified as the superposition of harmonic thermal action and steady-state temperature action, and the analytical solution to the temperature field of multistory wall under harmonic heat action is obtained by using the variable separation method. Secondly, The annual temperature difference and the daily temperature difference obtained from the analytical solution are combined to obtain the temperature load of the enclosure structure. Then the maximum volume deformation of the wall is calculated by combining the equivalent temperature load with the equivalent temperature load caused by the dry shrinkage deformation of the masonry wall. The internal force of the top floor wall is obtained by using the method of frame analogy and finite element analysis, and the distribution law of shear force in the wall is obtained. The results of the calculation by the bent frame method show that the shear force in the wall increases from the middle window wall to the outermost window wall. The results of finite element analysis show that the shear force of the second window wall at the outer end is the largest, except that the wall between the outer end window is subjected to axial tension, and the wall between the windows is subjected to axial pressure. A simplified formula for calculating the temperature effect of the top wall of masonry building is derived. Comparing the advantages and disadvantages of the two methods, the accuracy of the internal force and the distribution of the internal force calculated by the finite element method is higher. Finally, By using the simplified formula of internal force of temperature and the formula of shear strength of masonry structure, the maximum expansion joint spacing of top wall under different working conditions and the minimum reinforcement ratio of wall without expansion joint or whether or not to install structural columns are calculated. Accordingly, the crack control measures of "release" and "resistance" are put forward.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU364

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