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

开发了一种具有系统送丝和回拉功能的新型焊接工艺，可以在结构低合金钢上自动组装单个或成组的锥形球头销。通过这种工艺和与高强度细颗粒混凝土的结合，可以生产出具有高比承载能力的非常细的复合截面，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-挠度行为尚未澄清。由于销钉具有不同的承载性能，因此，迄今为止，传统剪力连接件的结构模型和分析方法不能简单地转移。这是由于焊接工艺引起的尺寸效应、几何形状和材料性能。此外，混凝土和钢组合截面的特定比例以及新的承载荷载和跨度宽度方案导致对销连接延性的不同要求，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用于复合结构的销焊接工艺、调查力-挠度行为和开发描述具有销-剪力连接件的典型结构元件的机械行为的工程模型。

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.