Simultaneous effect of spatial variability of ground motion due to site conditions and SSI on the seismic response of multi-span viaducts

This work focuses on the effects of the spatial variability of the seismic motion due to site effects on the seismic response of multi-span viaducts on pile foundations. A methodology is proposed to include the effects of both soil-structure interaction and non-synchronous seismic actions in the nonlinear response of bridges. Then, some results of nonlinear dynamic analyses performed on a multi-span bridge founded on soft soil are presented. The deposit is characterized by an inclined layout of the bedrock and the seismic input is represented by a set of suitably selected real accelerograms. Comparisons with results obtained considering synchronous seismic motions demonstrate the influence of site effects on the response of long bridges

Seismic Response of Bridges Accounting for Soil-Structure Interaction effects and the Non-Synchronous Ground Motion due to 1D and 2D site analysis.

This work focuses on the effects of soil-structure interaction and the spatial variability of seismic motion due to site effects on the seismic response of a multi-span viaduct on pile foundations. In particular, site effects induced in a soft clay deposit by an inclined bedrock layout are evaluated through different models, characterised by an increasing level of accuracy, which allows determining the free-field motion that is adopted to perform soilstructure interaction analyses in the frame of the substructure approach. The seismic input is represented at the outcropping bedrock by a set of suitably selected and scaled real accelerograms. After a brief presentation of the adopted numerical procedure, analyses results are presented focusing on both site and structural response. Amplifications effects obtained from simplified linear equivalent 1D and nonlinear 2D site response models are compared, discussing the applicability of the simplified approach. Structural responses, obtained by considering the non-synchronous motion resulting from the local stratigraphic conditions, in conjunction with soil-structure interaction effects, are shown in terms of piers displacement and ductility demands. Furthermore, the role of soil structure interaction is clarified comparing results with those obtained from fixed base bridge models, proving that its contribution is more significant if the simplified model for site response is adopted

Engineering Reconnaissance following the October 2016 Central Italy Earthquakes. Version 2. Editors Paolo Zimmaro and Jonathan Stewart, Geotechnical Earthquake Engineering Reconnaissance GEER Association, Report No. GEER-050D

A team from the Geotechnical Extreme Events Reconnaissance (GEER) Association, supported by the National Science Foundation, has been mobilized to investigate geotechnical and geological aspects of the destructive earthquake sequence that occurred in Central Italy during a series of significant events October 26-30, 2016, which followed prior events August 24-29, 2016. GEER responded to the initial event sequence and reports resulting from that effort are published on the GEER web site. As before, GEER will operate in close collaboration with Italian engineers and scientists. GEER is also coordinating its reconnaissance activities to coincide with those of EERI, which will be led by Dr. Silvia Mazzoni. Giuseppe Lanzo, Professor at Sapienza University of Rome, and Jonathan P. Stewart, Professor and Chair of the Department of Civil and Environmental Engineering at UCLA, are the GEER team co-leaders. The US-based GEER team members participating in the investigation are Prof. Kevin Franke (Brigham Young University), Dr. Robert E. Kayen (US Geological Survey and UCLA), and Dr. Bret Lingwall (South Dakota School of Mines and Tech.). The GEER team is part of an international coordinated effort that involves cognizant Italian agencies (i.e. National Institute of Geophysics and Vulcanology, INGV; Rete dei Laboratori Universitari di Ingegneria Sismica, ReLuis; and European Centre for Training and Research in Earthquake Engineering, EUCENTRE Foundation and Italian Center for Seismic Microzonation and its Applications). Key Italian participants include: Prof. Luigi Di Sarno (ReLuis and University of Sannio), Profs. Sebastiano Foti and Filiberto Chiabrando (Politecnico di Torino), Dr. Fabrizio Galadini, Emanuela Falcucci, and Stefano Gori (INGV), Prof. Alessandro Pagliaroli (University of Chieti-Pescara), Dr. Giuseppe Scasserra and Prof. Filippo Santucci de Magistris (University of Molise), Prof. Francesco Silvestri (University of Napoli Federico II), Prof. Stefano Aversa (University of Napoli Parthenope) and MrDr. Paolo Tommasi (Consiglio Nazionale delle Ricerche, Rome). Also contributing to the GEER effort are researchers from New Zealand (Dr. Fernando Della Pasqua, GNS Science) and United Kingdom/Greece (team led by Prof. Anastasios Sextos, University of Bristol and Aristotle University of Thessaloniki). A full list of GEER team members will be compiled following deployment to the field. The GEER team assembled for this effort is multi-disciplinary, including geology, seismology, geotechnical engineering, structural engineering, and geomatics. Based on information gathered to date, field investigations for the GEER team and collaborators have focused on: (1) substantial surface fault rupture, apparently on the Mt. Vettore fault, (2) major rockfalls and landslides, including a large slide that dammed a river; and (3) building, bridge, and other infrastructure performance in villages and hamlets throughout the region, including many that had been well documented in reconnaissance following the 24-29 August event sequence. Earthquake engineering is an experience-driven field in which perishable data that can be used to advance our understanding should be systematically collected. The data collection will be performed using traditional mapping/observational methods and advanced imaging tools

Understanding Factors Associated With Psychomotor Subtypes of Delirium in Older Inpatients With Dementia

Objectives: Few studies have analyzed factors associated with delirium subtypes. In this study, we investigate factors associated with subtypes of delirium only in patients with dementia to provide insights on the possible prevention and treatments. Design: This is a cross-sectional study nested in the “Delirium Day” study, a nationwide Italian point-prevalence study. Setting and Participants: Older patients admitted to 205 acute and 92 rehabilitation hospital wards. Measures: Delirium was evaluated with the 4-AT and the motor subtypes with the Delirium Motor Subtype Scale. Dementia was defined by the presence of a documented diagnosis in the medical records and/or prescription of acetylcholinesterase inhibitors or memantine prior to admission. Results: Of the 1057 patients with dementia, 35% had delirium, with 25.6% hyperactive, 33.1% hypoactive, 34.5% mixed, and 6.7% nonmotor subtype. There were higher odds of having venous catheters in the hypoactive (OR 1.82, 95% CI 1.18-2.81) and mixed type of delirium (OR 2.23, CI 1.43-3.46), whereas higher odds of urinary catheters in the hypoactive (OR 2.91, CI 1.92-4.39), hyperactive (OR 1.99, CI 1.23-3.21), and mixed types of delirium (OR 2.05, CI 1.36-3.07). We found higher odds of antipsychotics both in the hyperactive (OR 2.87, CI 1.81-4.54) and mixed subtype (OR 1.84, CI 1.24-2.75), whereas higher odds of antibiotics was present only in the mixed subtype (OR 1.91, CI 1.26-2.87). Conclusions and Implications: In patients with dementia, the mixed delirium subtype is the most prevalent followed by the hypoactive, hyperactive, and nonmotor subtype. Motor subtypes of delirium may be triggered by clinical factors, including the use of venous and urinary catheters, and the use of antipsychotics. Future studies are necessary to provide further insights on the possible pathophysiology of delirium in patients with dementia and to address the optimization of the management of potential risk factors