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Fatigue behavior of composite dowels due to the interacting damage processes of steel and concrete

钢和混凝土相互作用损伤过程导致复合销钉的疲劳行为

基本信息

批准号：
287311725
负责人：
Professor Dr.-Ing. Markus Feldmann
金额：
--
依托单位：
Institut und Lehrstuhl für Stahlbau, Leichtmetallbau
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2016
资助国家：
德国
起止时间：
2015-12-31 至 2020-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/287311725?language=en
关键词：
Fatigue behavior composite dowels due

项目摘要

Composite dowels for steel-concrete-composite beams are either steel strips welded vertically to the top flange of steel beams or webs of single-flange-steel profiles that have upward open recesses for use in bridge construction. Here, fatigue processes of the steel, the concrete or a combination of both can lead to a premature fatigue failure of the composite dowel. The damage processes of the concrete result from a multiaxial stress state in the recesses, leading to a cyclical inelastic slip increase. The inelastic slip accumulates over the load cycles and remains constant in the connection, even after release of external loading. Crack initiation and crack propagation in the steel strip enhance the inelastic slip, significantly. The inelastic slip causes a reduction of composite action yielding an increase of local bending moments in the steel beam and the concrete slab as well as rearrangements of internal forces along the composite connection. In consequence, the hypothesis of an initially rigid connection between steel and concrete, which is assumed in bridge design, becomes invalid. The complex interactions between multiaxial concrete fatigue and steel fatigue as well as the rearrangement of internal forces were not yet the subject of research. In this project, the interacting damage processes of steel and concrete are analyzed by experimental and theoretical investigations in order to clarify and model the fatigue behavior of composite dowels.

用于钢-混凝土组合梁的组合销是垂直焊接到钢梁的顶部翼缘的钢带，或者是具有用于桥梁建设的向上开口凹部的单翼缘钢型材的腹板。在此，钢、混凝土或两者的组合的疲劳过程可导致复合销钉的过早疲劳失效。混凝土的损伤过程是由于凹槽内的多轴应力状态导致的循环非弹性滑移增加。非弹性滑移在载荷循环中累积，并且在连接中保持恒定，即使在外部载荷释放之后。钢带中的裂纹萌生和裂纹扩展显著地增强了非弹性滑移。非弹性滑移导致组合作用的减小，从而导致钢梁和混凝土板中局部弯矩的增加以及组合连接处沿着内力的重新排列。因此，在桥梁设计中假定的钢和混凝土之间的初始刚性连接的假设变得无效。多轴混凝土疲劳和钢筋疲劳之间的复杂相互作用以及内力的重新排列尚未成为研究的主题。本计画以实验与理论研究分析钢与混凝土之交互作用损伤过程，以阐明复合材料传力杆之疲劳行为并建立其模型。