This article presents the results and analysis of Acoustic Emission (AE) as recorded in a reinforced concrete (RC) slab supported by four steel columns and subjected to earthquake-type dynamic loading on a shake table. Fifteen seismic simulations were conducted using an accelerogram registered during the Campano-Lucano earthquake (Italy, 1980). The peak acceleration applied to the shake table was increased until the slab reinforcement was on the brink of yielding and slippage of the bars within the concrete occurred. This limit state is commonly associated with low-to-moderate intensity earthquakes in earthquake-prone regions. The evolution of damage to the slab was monitored in terms of AE energy and the history of plastic strain energy was calculated from the acceleration and displacement measurements. A good correlation was found between the energy dissipated by the concrete through plastic deformations and the AE energy associated with concrete cracking and friction. On this basis, a tentative formula is proposed for predicting the level of damage to RC slabs, based on the AE energy recorded by sensors located near the region of expected damage concentration under lateral loads.

This paper offers a detailed, quantitative and exhaustive experimental comparison in terms of mechanical properties of three different layouts of carbon composite materials (CFRP) used to strengthen existing old timber beams highly affected by diverse natural defects and biological attacks, testing the use of pultruded laminate attached on the tension side of the element (LR), CFRP fabrics totally U-shape wrapping the timber element (UR), and the combined use of both reinforcement solutions (UR-P). Moreover, unidirectional and bidirectional fabrics were considered and compared. Timber elements used for the experimental program were extracted from a recent rehabilitation of the roof of the current Faculty of Law building, University of Granada (Spain), catalogued as a historical edifice. Experimental results from bending tests show that in all cases reinforcement provides a clear improvement in terms of bending capacity and stiffness as compared with the control specimens (without reinforcement). However, improvements in terms of ductility differ considerably depending on the kind of layout.