项贻强 ,何百达.考虑疲劳损伤的栓钉式组合梁剩余承载力计算方法[J].湖南大学学报:自然科学版,2020,(9):33~39
考虑疲劳损伤的栓钉式组合梁剩余承载力计算方法
Calculation Method for Residual Bearing Capacity of Composite Beams with Studs Considering Fatigue Damage
  
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中文关键词:  钢-混组合梁  疲劳  承载力  累计损伤  初始缺陷  计算
英文关键词:steel-concrete composite beam  fatigue  bearing capacity  accumulative damage  initial defect  calculation
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作者单位
项贻强 ,何百达 (浙江大学 建筑工程学院浙江 杭州 310058) 
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中文摘要:
      为研究钢-混组合梁在疲劳荷载下剩余承载力退化规律,引入考虑栓钉初始缺陷的基于断裂力学的承载力退化模型及经典钢梁、混凝土板承载力退化模型,并通过考虑不同疲劳荷载后退化为非完全抗剪结构的剩余极限承载力计算模型,建立了组合梁在常幅疲劳荷载下的剩余承载力预测计算方法,通过典型5组试验梁疲劳试验数据的对比验证了所提出的预测方法的有效性,在此基础上对关键影响因素进行了参数分析.结果表明:本文提出的承载力计算方法具有较高的准确性,误差控制在8%以内;疲劳加载下,组合梁各构件强度以不同速率发生退化,栓钉最快,钢梁次之,混凝土板最慢,且加载前期组合梁承载力退化程度由钢梁主导,后期由栓钉连接件主导;承载力退化速率随着加载次数的增加而不断增加,前期增长较缓,基本呈线性分布,后期增加迅速,呈指数型分布,其后期承载力衰减占总衰减的比例可高达70%以上;栓钉间距(抗剪连接度)、栓钉初始缺陷、荷载幅值是控制疲劳承载力退化的重要因素,需在工程设计中加以控制以满足桥梁正常运营.
英文摘要:
      In order to study the degradation law of residual bearing capacity of steel-concrete composite beams under fatigue loading, the classical steel beam and concrete slab bearing capacity degradation model and the fracture mechanics-based bearing capacity degradation model considering the initial defect of studs were taken to study. By considering the residual ultimate bearing capacity calculation model after degrading into incompletely sheared structures under fatigue loading, a prediction calculation method for the residual bearing capacity of composite beams was established. The validity of the proposed prediction method was verified by comparing the fatigue test data of five typical test beams. On this basis,some parameter analyses of the key influencing factors were carried out. The results show that the calculation method of bearing capacity proposed in this paper has high accuracy and the error is within 8%. Under fatigue loading, the strength of each component of composite beam is degraded at different rates. The stud degrades the fastest, the steel beam is the second, and the concrete slab is the slowest. The degradation degree of the bearing capacity of the composite beam in the early stage of loading stage is dominated by the steel beam, and it is dominated by the studs in the later stage. The degradation rate of the bearing capacity increases with the increase of the loading times. The growth of the bearing capacity in the early stage is slow, basically in a linear distribution, and later it increases rapidly in an exponential manner. The ratio of later bearing capacity attenuation to total attenuation can be more than 70%. The stud spacing(degree of shear connection),initial stud defects, and load amplitude are important factors in controlling the degradation of fatigue capacity. They are necessary to be controlled in engineering design to satisfy the normal operation of the bridges.
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