【摘要】 基于预应力筋与混凝土共同承载的理念,在分析预应力模拟的等效荷载法和实体力筋降温法基础上,根据力筋应力计算式的物理意义,提出了一种模拟有效预应力的等效荷载-实体力筋降温法。首先建立预应力结构的无筋有限元模型,通过等效荷载法计算出无筋模型的混凝土弹性收缩,根据该弹性收缩量获得考虑混凝土弹性收缩的对应于有效预应力的等效降温值;再建立预应力结构的有筋模型,通过在有筋模型中对预应力筋单元施加该等效降温荷载实现有效预应力的准确模拟。该方法能在多种通用有限元软件中通过两步建模计算实现,可以正确模拟结构在有效预应力作用下的初始状态,避免传统实体力筋法施加降温模拟有效预应力不准确的缺点。该建模方法为模拟预应力混凝土结构张拉加载、后续加载的受力分析,提供了又一种有效的方法。多个算例验证了本方法的可行性和有效性。更多还原

【Abstract】 According to the idea of bearing load together by prestressing tendons and concrete structure,based on the method of equivalent load and method of temperature reduction on prestressing tendon for prestress simulation,a method of equivalent load and temperature reduction on prestressing tendons for prestress simulation is proposed based on the physical meaning of prestressing tendon stress calculation equation. First,the elastic shrinkage of concrete is calculated by equivalent load method with the established prestress FE model without tendon,the equivalent temperature reduction value corresponding to the effective prestress is obtained considering the elastic shrinkage of concrete. Second,the prestress structure model with tendon is built,the equivalent temperature reduction load is assigned on prestressing tendon in the model to achieve accurate simulation of the effective prestress. This method can be realized using 2-step modeling analysis in various general finite element softwares,it can properly simulate the initial state of the structure under the effective prestress to avoid the inaccurate effective prestress simulation in the traditional method of using solid prestressing tendon for temperature reduction. The modeling method provided an effective way to simulate the tensioning load and subsequent loading on prestressed concrete structure,and the feasibility and effectiveness of this method is verified by multiple examples.更多还原