基于B3模型的竖向构件差异变形分析

Differential Deformation Analysis of Vertical Member Based on B3 Model

为研究巨型框架伸臂核心筒结构中由收缩和徐变引起的巨柱和核心筒的竖向差异变形,基于B3收缩徐变模型,采用应变增量法进行MATLAB编程,模拟荷载逐层施加的实际施工过程。对某一巨型框架伸臂核心筒结构进行了研究,考虑施工过程、混凝土收缩和徐变影响,对高层混凝土结构构件在竖向荷载作用下的竖向变形进行了计算;计算构件在楼板施工前后巨柱和核心筒的弹性、非弹性缩短以及竖向差异变形;进行了差异缩短变形分析,采用逐层修正法进行补偿。结果表明:考虑重力荷载、混凝土收缩和徐变时,巨柱和钢筋混凝土筒由收缩和徐变产生的非弹性变形占总变形的50%以上,且该比例随时间呈增大趋势;巨柱和核心筒的收缩变形远小于徐变变形,收缩和徐变变形最终趋于一定值;楼板施工结束时竖向变形近似相等的构件,在楼板施工后一定时期的竖向差异变形很大;若顶层楼板施工结束时荷载全部施加完毕,则楼板施工后的最大竖向变形值出现在中间某一层;对于有具体要求的特殊结构,采用逐层修正法可降低差异变形在伸臂桁架中引起的附加内力。

In order to study the vertical differential deformation between super columns and corewalls due to shrinkage and creep in outrigger braced mega frame core-wall structure, 133 model was applied to revealing the shrinkage and creep behavior of a tall outrigger braced mega frame core-wall structure. Through building a MATLAB program, strain incremental method was used to simulate the virtual construction process of the building by applying load sequentially story by story. The vertical deformation under gravity load was studied by taking into account the construction process, shrinkage and creep of concrete. 13ased on the proposed method, the compensation, the vertical deformation and the differential deformation before and subsequent to casting of floor were estimated. Differential deformation compensation was analyzed and elevation compensation for each floor was also calculated. Results show that the inelastic deformation due to shrinkage and creep of core-walls and super-columns take up 50 percent of the total deformation. There is a tendency to increase with the development of shrinkage and creep. The shrinkage deformations of super-columns and core-walls are much smaller than the creep deformation, and the ultimate shrinkage and creep deformation tend to constant. The vertical deformations of members are approximately equal to the casting of floor while they are greatly different subsequent to the casting of floor. The maximum deformation subsequent to the casting of floor occurs some middle floor assuming that all loads have been applied after the top floor is casted. Compensation for each floor can significantly minimize the additional force of the outriggers caused by differential shortening for some special structures.