箱外体内预应力加固施工控制研究

Research on Tensioning Control of Bonded Prestressed Reinforcement Outside the Box Girder

某38+3×60+38 m变截面预应力连续箱梁桥多跨箱梁底板跨中存在横向裂缝,需通过增设箱外体内预应力束进行加固。本文主要通过预应力施工期锚下应力监控及关键截面混凝土应力监控,分析张拉过程中产生的实际预应力损失,同时对预应力张拉过程进行研究并提出控制措施,使完工后桥梁预应力状态满足设计要求。

A 38+3×60+38 m variable cross-section prestressed continuous Box-girder bridge has transverse cracks in the middle of the bottom plate on multi span,which needs to be reinforced by adding bonded prestress outside the box.This article mainly analyzes the actual prestress loss during the tensioning process by monitoring the stress under the anchor and the stress of the key section concrete during the prestressed construction period.Meanwhile,it researchs the prestress tensioning control and proposes control measures to ensure that the prestressed state of the bridge meets the design requirements after completion.