体内外预应力混合配索桥梁设计中分阶段预应力配置设计

体内外预应力筋混合配索的桥梁设计方案,可利用体内索承担悬臂浇注施工荷载,又可利用体外索承担二期恒载和使用阶段荷载，并可发挥体外预应力筋在使用阶段易于检测与更换的优点。但在预应力筋混合配索中,不同的配索方案会导致体内体外预应力的布置和用量存在差异,也决定桥梁的应力状态。本文以实际工程为背景,以体内索承担施工阶段荷载,体外索承担二期恒载和使用荷载为原则,完成了施工过程中的不同配索优化,重点介绍了不同体内预应力索的设置方案,以及相应的体外预应力索的设计,确定了最终的桥梁设计方案与桥梁应力状态。相关设计过程可为类似混合配索的预应力连续梁或连续刚构桥提供参考。

Stage-by-Stage Prestressing Arrangement Design in the Design of Bridges with Hybrid Internal and External Prestressing Tendons

In the design scheme of a bridge with external prestressing tendons and hybrid internal and external tendons, the internal tendons can bear the load in cantilever casting construction, the external tendons can bear the superimposed dead load and the service load, and the external prestressing tendons are easy to inspect and replace in the service stage. However, in the design of prestressing tendons and hybrid tendons, different tendon arrangement schemes will lead to differences in the layout and number of internal and external prestressing tendons and determine the stress state of the bridge. This paper optimized different tendons in an engineering project during the construction process based on the principle that the internal tendons bear the load in the construction stage while the external tendons bear the superimposed dead load and the service load, highlighted the arrangement schemes of different internal prestressing tendons and the corresponding design of external prestressing tendons, and determined the final bridge design scheme and bridge stress state. The relevant design process can provide references for similar prestressed con-tinuous girder or continuous rigid-frame bridges with hybrid tendons.