【作者】 索清辉；

【导师】 赵世春；

【作者基本信息】 西南交通大学 ， 结构工程， 2002， 硕士

【摘要】 由于预应力混凝土的应用越来越广，预应力在不同的结构形式中出现，由于建筑功能的要求，结构的局部跨度较大，要求采用预应力形式，非预应力部分对预应力建立的影响成为设计中需要考虑的问题。文中建立了三榀局部采用预应力的框架，讨论了非预应力框架对预应力建立的影响，以及由于非预应力框架部分与预应力长期损失相互作用对预应力的影响。为了研究，框架中预应力梁的截面尺寸、预应力筋的配筋率、形状和张拉控制应力都相同。文中应用了有限元程序ANSYS对框架进行了模拟，建模中，混凝土采用程序中的DP材料。计算过程如下： 建立框架的结构模型，将预应力作用按等效荷载加在结构上，这一过程模拟张拉预应力钢筋后，施加外荷载前，结构处于的状态。 计算出预应力的长期损失即混凝土的收、缩徐变以及钢筋松弛引起的预应力损失，分别算出预应力损失随时间的变化在张拉后1、60、180天的有效预应力值，将有效预应力作用按等效荷载加在框架上，并且将框架在正常使用状态的恒、活荷载加上。分三个荷载步模拟框架正常使用状态。 通过分析和计算，可以得出以下结论： (1)框架的约束对预应力建立的影响在设计中是应该考虑的。尤其当约束作用较大时，会造成较大的预应力损失。 (2)可以利用框架计算中的D值法近似的估计预应力的损失。 (3)随时间的发展，每个结构的预应力度有递减的趋势，随约束刚度的增大，结构的预应力度递减的趋势增大。更多还原

【Abstract】 With the development of the prostressod concrete, it can he used in different building structure. For the requirement of architectural function,the partial span of structure is large, prestressed concrete must be used.More attention should be payed to the consequence of reinforced concrete to prestress when designing. This paper discussed the consequence of the constrain of reinforced concreteN creep and contraction of concrete and relaxation of reinforcing steel to prestress of three frame constructions. For discussing the area of cross section ., the ratio of reinforcing steel and the shape of prestressed re in forcement are all same. Finite-element program ANSYS was used to simulating the frames.DP material was used for concrete in simulating. The procedure of calculating is as follows:Establish the model of frame, the prestress was applied to frame as equivalent load which simulated the state of frame before the load applied on it.Calculated the loss of prestress with development of time. Apply the effective pro-stress of 3> 60 and 180 days after prestressing.Then apply the load on the frame simulating the structure in three load step.After analysing and calculating,the paper drew the conculsions as follows:The reinforced concret part of structure can lead the loss of prestress,the loss will increase with increasing of stiffness of constraint.The loss of prestross can bo calcualated approximately.With the development of time,the prestress decrease;With the increase of stiffness of constraint, the tendency of the decrease of prestress increases.更多还原