Experimental study on the active continuity of HCS structural floors using Iron-based Shape-Memory Alloy rebars

Abstract

[eng] Despite the relatively recent introduction of Iron-based Shape-Memory Alloys (Fe-SMA) into structural engineering, more than 150 real applications have been performed to date in Central Europe, especially in retrofitting projects. Thanks to the Shape-Memory Effect, a prestrained and correctly anchored Fe-SMA bar can generate recovery stresses when heated up to 160 °C (activation) or more, and then cooled down. This paper presents research results about using Fe-SMA reinforcing bars as active (prestressed) continuity reinforcement in the hogging bending moment region of Hollow Core Slabs structural floors (HCS-sf). An experimental campaign was designed and carried out on eight HCS-sf specimens, four with concrete topping and four without, and two different slab heights. Using the HCS-sf specimens with the activated Fe-SMA bars resulted in better behaviour in the Service Limit State, which preliminarily proved the effectiveness of the proposed methodology for the specimens with concrete topping, although construction problems arose with the specimens without concrete topping.