j.issn.1671-6833.2021.03.018]
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单箱多室宽幅箱梁桥施工剪力滞效应()

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《郑州大学学报(工学版)》[ISSN:1671-6833/CN:41-1339/T]

Title:: Shear Lag Effect of Wide Single Box Bridge with Multi-cell in Construction

Author(s):: Zhang Junfeng; Chen He; Yang Shounan; Li Rujian; Li Jie; Chen Huai;; School of Civil Engineering, Zhengzhou University;

Keywords:: wide box bridge; single box with multi-cell; construction stage; shear lag effect

摘要:: 为探究宽幅箱梁在悬臂浇筑施工过程中的剪力滞效应及随施工阶段的变化,以某单箱五室四跨连续梁桥为例对其施工过程进行了仿真模拟,分析了混凝土浇筑¸预应力钢束张拉以及合龙等单个施工步骤在关键截面顶底板正应力的横向分布特征结果表明:各种荷载作用下的截面正应力横向分布可视为截面“整体”剪力滞效应和各腹板自身“局部”剪力滞效应的叠加,且前者源于各腹板剪应力的横向分布不均截面上两种效应的权重与箱室数量¸悬臂长度以及荷载类型等因素有关:箱室数量越多,整体效应越明显混凝土浇筑和钢束张拉在根部截面所引起的剪力滞效应主要体现在顶板,并且随悬臂长度的增加,整体效应凸显而局部效应减弱另外,混凝土浇筑较钢束张拉所引起的整体效应更为明显。

Abstract:: Studies were initiated for the shear lag effect of the wide single box bridge with multi-cell during cantilever construction and its evolution in the construction. A single-box with five cells four-span continuous PC bridge was taken as an example, and the whole construction process was simulated numerically. Analyses were focused on the normal stresses in the roof and bottom plate of several critical sections, caused by concrete pouring, prestressing, closure and system transformation singly. The results showed that the transverse distributions of normal stresses could be regarded as the superposition of “global” shear lag effect of the whole section and “local” shear lag effect of each web, and the former origins from the shear stress difference in webs. Moreover, the proportions of the two effects were related to the cell number, cantilever length and load type. The global effect increased with the cell number. The shear lag effect caused by the concrete pouring and prestressing in the root section was remarkable in the roof but not the bottom plate, and the global effect increased with the cantilever length. Additionally, the global effect caused by the concrete pouring was more evident than that caused by prestressing.

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更新日期/Last Update: 2021-06-24