托架牛腿预埋区混凝土加固处理及应力分析

Analysis of Concrete Reinforcement Treatment and Stress in Pre-Embedded Area of Bracket Corbels

大跨度高墩悬灌梁桥施工过程中,需在桥梁墩身预埋托架,托架牛腿须具较大竖向承载力,而牛腿预埋常需切断墩身竖向主筋或对模板进行切割开孔,造成牛腿下方混凝土难以浇筑密实。牛腿受荷后,牛腿下缘混凝土易开裂,给墩身结构带来质量隐患及外观影响。本文结合常用钢棒预埋加固方法并基于数值软件对钢棒孔道周边混凝土真实受力状态进行分析,根据计算结果及工程实际针对性提出墩身施工时先预埋套管,套管外侧安装孔口周边加强螺旋筋,而后穿入钢棒的方案,避免了牛腿下缘混凝土开裂,施工效果良好,可为今后同类型施工提供借鉴。

In the construction process of a large-span high-pier cantilevered girder bridge,it is necessary to pre-embed brackets at the bridge piers,and the bracket corbels need to have a large vertical bearing capacity,and the pre-embedding of the corbels requires cutting off the vertical main reinforcement of the pier or cut the formwork for embedding,which makes it difficult to pour the concrete below the corbel tightly.After the corbel is loaded,the concrete at the lower edge of the corbel is easily cracked,which brings hidden damage to the quality and appearance influence on the pier structure.This paper analyzes the real stress state of the concrete around the steel rod hole based on the commonly used steel rod pre-embedding reinforcement method and numerical software,and according to the calculation results and the actual project,it is proposed that the casing should be embedded first during the construction,and the reinforcing spiral rib around the hole should be installed outside the casing,and then the steel rod should be inserted,which avoids the concrete cracking at the lower edge of the corbel,and a good construction effect is achieved.It can provide reference and guidance for the same type of construction methods in the future.