Preliminary Observations From Biaxial Testing Of A Two-Storey, Two-By-One Bay, Reinforced Concrete Slotted Beam Superassembly

Displacement incompatibility between reinforced concrete moment frames and precast flooring systems has been shown experimentally, and in historical earthquakes, to be an area of concern. Plastic hinge formation necessitates beam damage and the resulting elongation of the beam reduces the seating length of the floor, exacerbates the floor damage and induces unanticipated force distributions in the system. In severe cases this can lead to collapse. The slotted beam is a detail that protects the integrity of the floor diaphragm, respects the hierarchy of strengths intended by the designer and sustains less damage. The detail provides the same ductility and moment resistance as traditional details, whilst exhibiting improved structural performance. This is achieved with only a subtle change in the detailing and no increase in build cost. This paper briefly presents the development of the slotted beam in reinforced concrete. The design and construction of a large scale reinforced concrete slotted beam superassembly is described. The experimental method used to undertake biaxial quasi-static testing is introduced. Preliminary observations from the experiment are presented. It is shown that the reinforced concrete slotted beam is a viable replacement for the traditional monolithic detail. Extremely promising structural performance and significantly reduced damage compared to monolithic reinforced concrete details is presented.