High temperature push-out tests on demountable shear connectors of steel-concrete composite beams

Abstract

[EN] There is no denying that there is a growing need for reusable systems in the construction industry. This is not only a by-product of the increasing demand of materials, but also a necessity to reduce greenhouse gas emissions associated to the manufacturing process of construction components. Reusable systems aim to solidify the transition from a linear economy model to a circular economy model, where the lifecycle of materials is extended overtime. However, there are several factors that might hinder the reusability of structural components, ranging from regular use over a time period to accidental situations, such as earthquakes and fires.

This experimental study focuses its efforts on the analysis of demountable shear connectors for composite structural systems under the influence of high temperatures that resemble a situation of fire. The main idea behind this experimental campaign is to combine a standard push-out test, where a specimen composed by a HEB-260 steel profile with reinforced concrete slabs connected to its flanges via high strength bolts is subjected to a vertical force by utilizing a hydraulic jack with a simultaneous thermal action.

The tests reproduce a previous experimental campaign performed at the University of Luxembourg (cylinder and coupler systems), but subjected to 4 different temperatures (20, 300, 500 and 600 °C). The loss of strength of the connectors with the temperature, the failure mode and the reusability after a situation of fire are discussed in the present study.