（1 湖南中大建设工程检测技术有限公司,长沙 410205； 2 湖南中加土木工程加固技术有限公司,长沙 410205；3湖南大学土木工程学院，长沙 410012；）

[摘要]某高速公路大型收费站收费大棚由弧线形主网架和椭圆壳形雨棚网架两部分组成，通过钢管混凝土柱-钢牛腿节点连接。该工程在使用过程中存在安全问题，为确保安全性，现场对网架结构进行详细检测。在现场检测的基础上，利用MIDAS/GEN有限元软件建立两个网架的桁架系计算模型，进行结构强度、整体变形和考虑初始缺陷的非线性屈曲分析。利用ABAQUS软件建立钢管混凝土柱-钢牛腿节点三维实体非线性有限元模型，由于受锈蚀及焊缝质量影响，牛腿部位出现承载力不足。两个网架的安全性鉴定等级综合评定均为C_su级，均不符合国家现行标准规范的要求。根据判定结果并结合实际情况，采用新增加强环和腹板的方式对钢管混凝土柱-钢牛腿节点进行加固处理，加固后钢牛腿的承载力得到显著提升，结构的安全状况得到改善。由于钢管对核心混凝土的约束作用增强，混凝土第三主应力出现轻微的提高，但未超过混凝土轴心抗压强度标准值。本文的研究成果可以为类似工程提供参考。

[关键词] 网架结构;检测鉴定;有限元;加固设计

中图分类号：TU356      文献标识码：A       文章编号：1002-848X（）

作者简介：李刚，硕士，工程师，Email :303857385@qq.com；谈忠坤，博士，高级工程师，一级注册结构工程师，Email :175336988@qq.com。

Evaluation and strengthening design for a large toll station grid structure

Li Gang ¹, Tan Zhongkun^1,2,3,Wang Youlin¹, Guo Qiwu¹ , Liang Bo¹, Tian Dailiang¹

(1 Hunan Zhong Da Construction Engineering Testing Technology Co.，Ltd.， Changsha 410205，China; 2 Hunan Zhong Jia Civil Engineering Strengthening Technology Co.，Ltd., Changsha 410205，China; 3School of Civil Engineering, Hunan University, Changsha 410012，China)

Abstract:A Large toll station grid structure on highway was composed of arc shaped main grid and ellipse shell shaped canopy structure and the two part of grid structures were connected by concrete-filled steel tubular stub columns and steel corbel(CFST-SC). Problems of structure were found in the process of using. In order to ensure the safety, a detailed inspection of the grid structure was done on site. On the basis of field tests, MIDAS/GEN was used to establish the finite truss model of two part of grid structures. Strength calculation, Deformation and Stability with original defects were discussed. ABAQUS was used to establish the 3D finite model to analyze the stress of CFST-SC. The capacity of corbel was low as the effects of corrosion and welding quality. Both of the two grid structures safety evaluation appraisal were C_su level, Which were not consistent with existing national standards requirements. According to the evaluation results and actual situation, CFST-SC was reinforced by adding stiffening ring and web. After reinforcement, the bearing capacity of steel corbel was greatly improved and the structural safety was increased. Due to the restriction effect from steel to concrete, the third principal stress of concrete was slightly improved but not exceed the standard value of concrete axial compressive strength.The conclusion of this paper could give recommendations for similar projects.

Keywords: grid structure; evaluation; finite ;strengthening design

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