预应力碳纤维布加固混凝土梁预应力长期损失的增量微分法

为深入了解预应力碳纤维布加固钢筋混凝土梁的预应力长期损失,采用随时间变化的换算弹性模量方法,建立了考虑混凝土收缩徐变、胶层徐变及钢筋混凝土梁与碳纤维布界面滑移的预应力长期损失增量微分模型,得到了给定边界条件和荷载形式下的预应力长期损失闭合解。为验证该方法的有效性,对相关学者的试验梁进行了长期预应力损失的计算。计算结果表明,所建立的微分增量模型可以用来预测预应力碳纤维布加固钢筋混凝土梁的预应力长期损失。

Incremental differential model for long-term prestress losses ofreinforced concrete beams strengthened with prestressed CFRP sheets

In order to investigate the long-term prestress losses of reinforced concrete (RC ) beams strengthened with prestressed carbon fiber reinforced polymer (CFRP)sheets,an incremental differential model is presented in this paper by using the conversion elastic modulus method.In this model,the creep and shrinkage of concrete,creep of adhesive layer and interfacial slip at the concrete-to-CFRP interface are all considered.The closed-form solution for long-term prestress loss is obtained by given boundary conditions and load patterns.The effectiveness of proposed model is validated by being compared with experimental results of the relative researchers’test beams in term of long-term prestress losses.The calculated results show that the proposed model can be used for predicting the long-term prestress losses of reinforced concrete beams strengthened with prestressed CFRP sheets.