Shake-table testing of two u-shaped RC walls: overview of the project Eries-ALL4waLL

Abstract

This paper summarises the project ERIES-ALL4wALL, “Smart ALLoys for WALLs: towards durable structures with long service lives and minimal seismic residual displacements”, which was funded through the Engineering Research Infrastructures for European Synergies (ERIES) Transnational Access program. The project advances the understanding of the seismic behaviour of reinforced concrete (RC) U-shaped core walls by investigating two factors that commonly contribute to poor structural response and limit post-earthquake serviceability, namely torsional effects and excessive residual displacements. The latter can be minimised through a mitigation principle that consists in replacing partially some of the longitudinal steel reinforcement at the wall base by smart alloy rebars. The project aims at demonstrating this technological innovation, contributing to ensure target performances for buildings with significantly longer service lives, which should be an aim for sustainable design and assessment. In scientific and technical terms, the project is concretized in three main fronts of research: (i) the shake-table testing of two large-scale U-shaped RC wall units in the National Laboratory for Civil Engineering (LNEC), in Lisbon – namely: one conventionally-reinforced unit, and a second one including the smart alloy rebars; (ii) the development of state-of-the-art and state-of-the-practice simulation models to estimate the response of the test units; (iii) the application of a set of novel instrumentation techniques, namely distributed fiber optic sensors along several reinforcing bars, video-based tracking measurements, an OptiTrack motion capture system, and extensive conventional instrumentation; in essence, it means these two units are the most extensively monitored walls so far tested in shake-table testing. The paper starts by addressing the project motivation, providing a global description, and listing its objectives. It then goes on to justify the sources of innovation and impact, as well as the articulation between the unique synergistic features of the assembled team of 15 user group members. It concludes with a description of the experimental programme, an overview of the employed numerical simulation techniques, and some leading results of the first wall unit tested. More complete and comparative results of the performance of both units, and of the associated blind prediction competition, will be unveiled during the conference presentation.