Experimental seismic response of a resilient 3-storey post-tensioned timber framed building with dissipative braces

Abstract

With the increased number of multi-storey buildings in seismic areas, research efforts have been focused on developing earthquake resilient systems, such as low-damage techniques based on the combination of post-tensioning and dissipating devices. This paper describes the experimental study performed on a 3-storey post-tensioned timber framed (Pres-Lam) building equipped with energy dissipating systems. The testing project consisted of three phases adopting different configurations of the experimental model: (1) post-tensioning to beam-column joints only, (2) post-tensioning and dissipative rocking mechanisms and (3) post-tensioning and dissipative braces. The main objective of this paper is to experimentally investigate on the seismic response of a large-scale specimen with dissipative braces located in high seismic area, considering construction details similar to those adopted in practical applications. During the experimental campaign, the test frame was subjected to more than one hundred ground motions considering a set of seven spectra-compatible earthquakes at increasing intensity levels. The dissipating bracing system with external replaceable hysteretic dampers improves the seismic resilience of multi-storey Pres-Lam buildings, showing inter-storey drift comparable to those with rocking walls, with full recentring capability and without structural damages or post-tensioning losses through seismic tests.

Self-centering seismic-resistant structures: Historical overview and state-of-the-art

“…Di Cesare et al (2017) developed a similar idea using long, prefabricated laminated timber connected by PT steel tendons or bars. Subsequently, Di Cesare et al (2020) experimentally confirmed the seismic performance of a three-dimensional, three-story timber building designed using a combination of rocking timber beam–column joints and replaceable hysteretic dampers. Rocking timber wall panels that resembled post-tensioned rocking concrete walls were also proposed and experimentally studied (Ganey et al, 2017; Moroder et al, 2018; Newcombe et al, 2008; Sarti et al, 2016; among others).…”

Experimental estimation of energy dissipated by multistorey post-tensioned timber framed buildings with anti-seismic dissipative devices

“…At lower seismic intensities (up to 25% -SLE) no significant variations of drift between the three testing configurations were observed, because the hysteretic devices remained substantially elastic. At higher PGA levels the dissipative bracing systems of BF model a significant reduction of storey drift was observed, with a slightly increase of base shear, due to the stiffness of the bracing system [15]. In particular at 100% of PGA the drift reduced of about 30% than the DF configuration.…”

“…The experimental model was a 3-D, 3-storey, 2/3 scaled post-tensioned glulam timber frame characterized by single bays in both directions, with dimensions in plant of 4 m x 3 m and inter-storey height of 2 m [14][15]. The prototype model was designed according to European code [16] for office use at first and second floors (live load of Q = 3 kPa) and considering a rooftop garden load (Q = 2 kPa).…”

“…acceleration, post-tensioning, equivalent damping) and local key parameters of the devices (e.g. number of cycles of UFPs) please refer to [13][14][15], [21][22]. Fig.…”

“…In this paper the experimental estimation of energy dissipated by a post-tensioned timber frame building tested with different anti-seismic hysteretic devices has been presented, based on the area under the base shear-displacement curve performed during experimental tests. A multistorey post-tensioned timber frame specimen was tested at the structural Laboratory of University pf Basilicata, alternatively combining the bare frame with two different types of energy dissipation systems [14][15]. The seismic response in terms of the main global and local hysteretic behaviour has been discussed and the amount of hysteretic energy dissipated by the different damper devices and by the frame have been investigated considering different seismic inputs at increasing PGA level, from a Service Level Earthquake (SLE) to a Design Base Earthquake (DBE).…”