不均匀积雪致大跨网架结构局部损伤分析  

Local Damages of Long-span Grid Structure Caused by Uneven Snow Cover

作　　者：刘晖[1,2] 黄昌昊 吉柏锋[1,2] LIU Hui;HUANG Changhao;JI Baifeng(School of Civil Engineering and Architecture,Wuhan University of Technology,Wuhan 430070,China;Hainan Institute of Wuhan University of Technology,Sanya 572025,China;China Construction Third Bureau Engineering Design Co.Ltd.,Wuhan 430070,China)

机构地区：[1]武汉理工大学土木工程与建筑学院,湖北武汉430070 [2]武汉理工大学海南研究院,海南三亚572025 [3]中建三局工程设计有限公司,湖北武汉430070

出　　处：《防灾减灾工程学报》2024年第1期99-108,共10页Journal of Disaster Prevention and Mitigation Engineering

基　　金：海南省自然科学基金(522CXTD517,522MS096,522RC879)资助。

摘　　要：网架结构管球连接处局部损伤是此类结构的重要安全隐患。在风致雪漂移引起的不均匀积雪荷载作用下,局部损伤会加剧,最终导致结构局部破坏。因此很有必要分析不均匀积雪荷载作用下带伤服役网架结构局部损伤劣化情况。采用CFD数值模拟技术,以一正放四角锥网架结构为研究背景,分析了在90°风向角、12 m/s风速下,持续降雪24 h中网架结构屋面不均匀积雪分布的变化情况,并建立可表征网架结构管球连接处存在裂纹损伤的多尺度模型,分析了网架结构节点存在不同裂纹尺寸局部损伤时,不均匀积雪致网架结构局部损伤劣化程度。结果表明:网架结构风致积雪不均匀程度非常显著,而且当网架结构管球连接处存在局部裂纹损伤时,在降雪中后期,有管球连接损伤的节点大多都出现了不同程度的裂纹扩展,节点为最不利分布的穿透型裂纹时,裂纹扩展最大为15.64 mm。说明在持续特大降雪这种极端荷载作用下,带伤服役网架结构局部损伤将进一步加剧,危及结构使用安全。Local damage of the pipe-ball joints in the grid structure poses a significant safety hazard.Such local damage will be aggravated under uneven snow cover caused by wind-induced snow drift-ing,eventually leading to partial structural failure.Therefore,it is necessary to analyze the degrada-tion of the structure with local damage under the action of uneven snow load.The CFD numerical sim-ulation technology is adopted to analyze the variation of uneven snow distribution on the roof of an or-thogonal quadrangular grid structure under the continuous snowfall for 24 hours at the 90°wind direc-tion and 12m/s wind speed.Then a multi-scale numerical model is established to characterize the crack damage at the pipe-ball joints of the grid structure,and the local damage deterioration degree of the grid structure caused by uneven snow cover is analyzed when there is local damage of different crack sizes at the joints of the grid structure.The results show that the uneven degree of the wind-in-duced snow cover on the grid structure is very significant,and when there are local crack damages at the pipe-ball joints of the grid structure,most of the joints with damage have different degrees of crack propagation in the middle and late stages of snowfall.The maximum crack propagation is 15.64 mm when the joint damage is the penetrating cracks with the most unfavorable distribution.It indicates that under the extreme load of continuous heavy snowfall,the local damages in the grid structure with ex-isting cracks will be further aggravated,endangering the service safety of the structure.

关 键 词：风致不均匀积雪 大跨网架结构 局部损伤 结构多尺度模型 

分 类 号：TU312.3[建筑科学—结构工程]