Ricerc@Sapienza

This paper presents a new soil-foundation macro-element model to allow efficient and sufficiently accurate consideration of soil-foundation-structure interaction in structural analysis. The model makes use of two constitutive models, a plasticity model which models the soil inelastic deformation, and an elastic uplift model, which captures the geometric non-linearity during uplift of the foundation. Further considerations are made to allow the macro-element to be efficiently implemented in a particular non-linear finite element software (Ruaumoko3D).

This paper describes the blind prediction carried out to simulate the response of a thin reinforced concrete wall tested under uni-directional (in-plane) quasi-static reverse cyclic loading. The specimen was a singly reinforced T-shaped wall panel with a shear-span ratio of 3.7. The response of the test specimen was simulated prior to the release of test results using a finite element model which had already been verified for its capabilities in capturing different failure patterns of rectangular walls, particularly out-of-plane instability.

This paper focuses on the development of energy dissipaters for rocking precast systems. The energy dissipaters developed in this work are to be used externally, having the advantages of being easy to inspect and replace after an earthquake. The main parameters to take into account for the development of the energy dissipaters are the cyclic behavior, the strength, and the ductility. The cyclic behavior has to be stable from cycle to cycle. The developed dissipater has to respond with adequate strength.

An experimental investigation was conducted to evaluate both residual capacity and the damage of the concrete material in previously damaged RC columns. Three circular columns, each caged to provide low, medium, and high level of confinement, were axially loaded to failure. All damaged columns were then cut into three pieces, and two cored cylinders were taken from each piece. The first core was prepared and instrumented for compression, whereas the second was sliced into a number of 25-mm disks for permeability testing.

Instability failure (also referred to as out-of-plane instability) has been observed in several experimental studies conducted on seismic performance of rectangular structural walls under in-plane loading. Observation of this failure pattern in some well-confined modern walls during the 2010 Chile and the 2011 Christchurch earthquakes has raised concerns about the reliability of current design code provisions.

The seismic design of fasteners used to anchor nonstructural components (NSCs) to concrete structures constitutes a crucial task within the context of a modern performance-based philosophy, which accounts for all the components of a building. This is particularly relevant when the NSCs are required to withstand strong seismic events with minor damage. The present paper introduces a new generation of high-performance post-installed anchors incorporating supplemental damping-referred to as EQ-Rod-for reducing the acceleration suffered by NSCs.

This research demonstrates the efficacy of 2–4 viscous dampers in self-centering rocking structures with bi‑linear elastic response, which is distinctly different to conventional fixed‑base structures. This study assesses the relative impact of 2–4 devices versus typical viscous dampers and 1–3 viscous devices. Performance is assessed by maximum displacement, total base shear, and maximum acceleration, which are indicative of structural, foundation and contents demand. Simultaneous reductions of displacement, base-shear and acceleration are only available with the 2–4 damper.

With the increasing demand for multi-storey timber buildings in areas with high wind loads and high seismic activity, stiff lateral load resisting systems are becoming a crucial design component. Post-tensioned Pres-Lam mass timber lift shafts and stairwell core walls not only provide a strong and very stiff lateral load resisting system, but also damage limiting response in the case of a large seismic event. This paper describes the results of experimental tests on Cross-Laminated Timber (CLT) Pres-Lam core walls tested under bi-directional quasi-static seismic loading.

Since 2010, twelve post-tensioned timber (Pres-Lam) buildings have been constructed throughout the world. The technology relies on unbonded post-tensioning tendons to provide moment capacity to beam-column, wall-foundation, or column-foundation connections. Supplemental energy dissipation can be introduced by mild steel bars or replaceable damping devices when designing buildings for high seismic risk areas. Creep within the timber elements leads to losses in post-tensioning force over time.

How can we evaluate the cost-effectiveness of retrofit interventions aiming at reducing the seismic vulnerability of an existing building? What level of shaking intensity should the retrofitted building sustain? These are open questions affecting either the pre-earthquake prevention, the post-earthquake emergency and the reconstruction phases. The (mis)conception that the cost of retrofit interventions would increase linearly with the level of safety required in designing the intervention often discourages stakeholders to consider alternative retrofit options.