Long-Term Experiments of Composite Steel-Concrete Beams

Abstract

This paper presents three sets of full-scale experiments aimed at the evaluation of the long-term behaviour of composite steel concrete beams designed with partial shear connection formed by a steel joist and a solid or composite concrete slab. All specimens were designed in accordance with Australian guidelines. In the first set of experiments three full scale simply-supported composite beams with solid concrete slabs having identical spans and cross sections were prepared and tested. The three beams were cast simultaneously in order to enable comparisons with respect to pouring and loading conditions. The second set of experiments was similar to the first one while using a composite slab instead of a solid one. The third set included the long-term testing of a two span continuous composite beam. A web side plate connection was placed at the internal support to reflect typical Australian detailing practice of flooring systems in which such a joint is usually adopted between secondary and primary beams. For this purpose, the supported solid concrete slab was continuous over the connection. The sustained load was applied by means of concrete blocks placed along the whole member length. The long-term response of these composite members was monitored by measuring the changes in deflections, curvature, strain and slip occurring over time. For each set of experiment, standard tests were carried out on concrete, steel and shear connectors to determine their material properties.