Summary After an earthquake, non‐negligible residual displacements may affect the serviceability of a base isolated structure, if the isolation system does not possess a good restoring capability. The permanent offset does not affect the performance unless the design is problematic for utilities, also considering possible concerns related to the maintenance of the devices. Starting from experimental and analytical results of previous studies, the restoring capability of Double Concave Friction Pendulum bearings is investigated in this paper. A simplified design suggestion for the estimation of maximum expected residual displacements for currently used friction pendulum systems is then validated. The study is based on controlled‐displacement and seismic input experiments, both performed under unidirectional motion. Several shaking table tests have been carried out on a three‐dimensional isolated specimen structure. The same sequence of seismic inputs was applied considering three different conditions of sliding surfaces corresponding to low, medium and high friction. The accumulation of residual displacements is also investigated by means of nonlinear dynamic analysis. Copyright © 2017 John Wiley & Sons, Ltd.

Themechanical properties of elastomers can change significantly due to air temperature variations. In particular, prolonged exposure to subzero temperatures can result in rubber crystallization, with a considerable increase in the shear stiffness of the material. As a result, the seismic response of structures with elastomeric isolators can be strongly influenced by air temperature. Current seismic codes, indeed, require an upper and lower bound analysis, using suitable modification factors, to account for the changes in the cyclic behavior of elastomeric isolators due to air temperature variations. In this study, the sensitivity of the cyclic behavior of elastomeric isolators to air temperature variations is investigated based on the experimental results of an extensive test program on six different elastomeric compounds for seismic isolators, characterized by a shear modulus ranging from 0.5 to 1.2MPa at 100% shear strain and 20◦C. The cyclic tests have been performed on small-size specimens, subjected to shear strain amplitudes and frequency of loading typical for elastomeric seismic isolators, at seven different air temperatures, ranging from 40 to−20◦C. The effects of rubber\ud crystallization due to prolonged exposure to low-temperatures have been also investigated. A finite element model for the evaluation of the temperature contour map inside a full-size\ud elastomeric isolator exposed to low air temperatures has been also developed. In the paper, the experimental outcomes are compared with the modification factors provided by the current\ud seismic codes to account for the temperature effects on the mechanical properties of elastomeric isolators

This article describes tests investigating a feasible source of passive damping for post-tensioned glue-laminated (glulam) timber structures. This innovative structural system adapts precast concrete PRESSS technology [Priestley et al., 1999] to engineered wood products combining the use of post-tensioned tendons with large timber members. Current testing is aimed at further improvement of the system through additional energy dissipation. Testing has favorably compared glue-laminated timber (not previously implemented in this way) with laminated veneer lumber (LVL) used in NewZealand. After initial benchmark testing with post-tensioning only, a simple, minimally invasive and replaceable type of hysteretic damper was added.

The personal experiences with a series of 57 conservatively treated extradural haematomas (EDH) are presented and the criteria for conservative management outlined. Main preconditions are absence of neurological deficit, close clinical supervision and repeated CT check-ups.

A wide experimental program on beam-column RC joints carried out in the framework of the DPC-Reluis Project (DPC: Department of Civil Protection, Reluis: Network of University Laboratories of Earthquake Engineering) is presented. All the experimental tests were performed at the Laboratory of Structures of the University of Basilicata, Potenza (Italy). The main objective of the experimental campaign is to study and compare the post-elastic behaviour of beam-column joints with different earthquake resistant design levels, indicating the role of some structural parameters such as the axial load value acting on the column, the beam dimensions, and the steel type, on the joint performances and failure mechanism. The analyses have mainly been devoted to improving the assessment procedures regarding existing buildings but also to verifying the prediction capability of the capacity models relevant to beam-column joints contained in literature and in the new seismic codes. Following a short description of the experimental methodologies used in other campaigns, the experimental program is presented, providing a detailed description of the specimens and of the testing set-up. This is followed by a report of the main results of the cyclic tests performed on the beam-column specimens which highlight the role played by axial load and seismic design level in determining the failure mechanism and the global response of the joints