Abstract
In recent years, the growing need for reducing non-structural damage after earthquakes has stimulated a dedicated effort to develop innovative types of fasteners for anchoring non-structural components (NSCs) to reinforced concrete (RC) host-structures. To contribute to such need, and building on previous research, this paper presents the results of a series of uni-directional shake-table tests of simulated NSCs anchored to concrete via: (1) expansion, and (2) chemical anchors; post-installed into: (a) uncracked, and (b) cracked concrete. Considering different construction details, the experimental investigation focused on traditional anchorage systems, alternative solutions comprising mortar filling into the gap clearance, and a low-damage system relying on supplemental damping devices, capable of reducing the acceleration of the NSCs as well as the force of the anchorage during seismic shakings. The experimental tests provided significant evidence on the beneficial effects of a dissipative anchorage protecting both the non-structural component and the anchorage itself, even during strong earthquakes. Moreover, when construction details allow to close the fixture clearance with a mortar filling, this stiffer solution provide an additional reduction of NSCs seismic accelerations and forces. Therefore, suggestions for further improvements of the adopted low-damage solution are also proposed.
Highlights
Non-structural components (NSCs) and building contents are often attached to reinforced concrete (RC) buildings using post-installed anchors
The three key variables of the system response monitored during the experiments were: (1) the acceleration of the driving mass (DMA) representing the NSCs; (2) the anchorage force Ffast and (3) the hysteretic behavior of the fastener, relative to the concrete block
The efficacy of the EQ-Rod prototypes in improving the seismic response of the system was determined by their capability of reducing the acceleration and force demands on the driving mass (NSC) and the anchorage, respectively, when compared to the same demand recorded using the traditional anchorage and the alternative solution
Summary
Non-structural components (NSCs) and building contents are often attached to reinforced concrete (RC) buildings using post-installed anchors (fasteners). Following a performance-based seismic design approach and with the aim to improve fastening techniques, a comprehensive experimental and numerical campaign was carried out at the University of Canterbury in 2008–2009 to develop a new generation of post-installed anchors, referred to as EQ-Rod (Earthquake Resistant fastener), able to resist the demands produced by severe seismic events, and capable of reducing the damage to the NSCs they fix (Pampanin et al 2008; Quintana Gallo et al 2018) This type of fastener relies upon the use of supplemental damping, either viscous and/or hysteretic, added in series and/or in parallel to a traditional fastener, and represents a first generation of low-damage system for this type of anchorage (Fig. 1). The most relevant features, results, and highlights of the whole experimental campaign are presented
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