Investigation of the composite action between steel and concrete of innovative small-scale pin-shear-connectors

一种新型焊接工艺的发展，具有系统的送丝和回拉，允许在低合金钢结构上，单个或成组地自动组装具有锥形底座的球头销。通过这一工艺，并与高强度细粒混凝土相结合，可以生产出高比承载能力的非常精细的复合截面，为结构应用开辟了新的领域。然而，与新型销的剪切连接的力-挠度行为尚未明确。到目前为止，传统剪切连接件的结构模型和分析方法不能简单地转移，因为销钉表现出不同的承载行为。这是由于焊接过程引起的尺度效应以及几何形状和材料行为。此外，混凝土和钢组合截面的特定比例以及承载载荷和跨宽的新场景对销钉连接的延性提出了不同的要求，以实现截面和系统的最大承载能力。因此，本提案的目标包括开发复合材料结构的销钉焊接工艺，对力-挠曲行为的调查以及描述带有销钉剪切连接器的典型结构元件力学行为的工程模型的开发。

The development of a novel welding process with systematic wire-feed and pullback allows for the automatic assembly of ball-headed pins with a cone-shaped base on structural low alloyed steels, singular or in groups. By means of this process and the combination with high-strength fine-grained concrete very filigree composite sections of high specific load carrying capacities can be produced, opening new fields for structural application. However, the force-deflection behaviour of the shear connection with the novel pins is not clarified yet. The structural models and analysis methods of conventional shear connectors so far cannot simply be transferred, since the pins exhibit a different load-bearing behaviour. This is due to scale effects and both geometric shape and material behaviour induced by the welding process.Furthermore the specific ratios of concrete and steel composite sections as well as new scenarios of bearing loads and span widths cause different requirements regarding the ductility of the pin connection, in order to achieve maximum load carrying capacities of cross section and system. Objectives of this proposal therefore include the development of the pin welding process for composite construction, the investigation on the force-deflection behaviour and the development of engineering models describing the mechanical behaviour of typical structural elements with pin-shear-connectors.