Seismic performance of fire damaged structures: preliminary analysis of a 14-story case study structure

Fires in residential buildings are one of the major and most frequent disasters affecting urban areas. Most fire-damaged buildings are repaired after the fire rather than demolished and replaced. In case of extreme fire events, the decision to repair the building usually involves extensive engineering investigation including materials testing and detailed damage assessment. However, these are often disregarded in case of small to medium size fires, where damage to structural elements may be less visible. In these cases, the repair process focuses on reinstating the aesthetic appearance of the building with limited consideration of how the strength of fireaffected structural elements may have been degraded. But what if the fire-affected building is sited in a seismic area? How will a fire-damaged building perform under seismic loading? The present paper presents an initial study that looks to help answer these questions. The paper evaluates the seismic performance of a typical high-rise reinforced concrete building in Istanbul (of tunnel-form construction), considering several fire damage scenarios. This region is considered for case study purposes due to its high seismic hazard and the high number of residential fires experienced every year (according to the data published by the Istanbul Fire Brigade). The case study structures are modelled in OpenSeesPY, with fire damage modelled considering deterioration in the material properties of the structural components under different scenarios of fire intensity and spread within the building. Nonlinear time history analyses are performed on the undamaged and fire-damaged structures to investigate the changes in the seismic response. The results highlight the increased seismic vulnerability of the fire-damaged structures and provide insights into which fire scenarios most affect the structure's seismic performance

Impact of corrosion deterioration on the seismic performance of steel frame structures

Steel structures designed before the introduction of modern seismic design codes may be characterised by high seismic vulnerability due to their reduced ductility capacity. Additionally, these structures may be affected by significant corrosion deterioration, as one of the major atmospheric degradation phenomena when built in corrosive environments. Corrosion deterioration leads to a thickness reduction of sections, reduced bearing capacity, stiffness degradation and loss of energy dissipation capacity. Thus, old-corroded steel structures located in seismically active regions could experience a reduction of their seismic performance, significantly increasing the failure probability under earthquake events. The present study investigates the effect of atmospheric corrosion deterioration on steel frames and uses a nonseismically designed three-storey moment-resisting frame for case-study purposes. Atmospheric corrosion models based on the recommendation of ISO 9224:2012 have been adopted considering a 50-years ageing time and modelled as uniform corrosion on steel members. A probabilistic seismic performance assessment of the pristine and ageing steel frames is performed through Incremental Dynamic Analyses (IDAs). IDAs are performed for a set of 43 ground motion records accounting for the influence of the earthquake input’s uncertainty (i.e., the record-to-record variability). The corrosion effects on the seismic performance are evaluated by monitoring both global and local engineering demand parameters (EDPs), allowing the development of seismic fragility functions at components- and system-level

Code-based seismic performance assessment of high-rise tunnel-form buildings in Turkey

Tunnel-form buildings are one of Turkey’s most common typologies for mass housing projects. They are known for their rapid construction process, relatively lower construction costs and shorter construction time. These structures are mainly composed of lightly reinforced thinsectioned shear walls, coupling beams and slabs and can reach up to 20 stories or even more in some cases. The design of these structures is typically based on force-based linear elastic procedures and relies on the behaviour factor and dominant vibration modes to estimate earthquake forces. Shear walls are designed and detailed according to frame and dual systems regulations. Moreover, the minimum reinforcements required by the code are usually sufficient since the shear wall area to floor area is high. In previous earthquakes, low- and mid-rise tunnelform buildings designed according to current standards exhibited high seismic performance. However, some drawbacks and limitations may characterise the design of taller structures. In this context, the present paper investigates the seismic performance of a 14-storey case study residential tunnel-form building located in Istanbul and considers two editions of the Turkish Building Seismic Code (i.e., the TBSC 2007 and 2018) for the performance assessment. A detailed non-linear finite element (FE) model was developed in OpenSeesPY to perform nonlinear time-history analyses considering a set of natural ground motion records. The numerical model considers the inelastic behaviour of the shear walls through fibre-based distributed plasticity elements aggregated with the bilinear shear response. The elastic response of the FE model was validated against the experimental results from ambient vibration monitoring. The comparative seismic performance assessment shows that the TBSC 2018 results in more severe damage estimation, hence highlighting potential drawbacks of buildings designed with previous standards

Impacto do desenvolvimento do agronegócio nas economias periféricas de Brasil e Paraguai

O artigo trata da inserção do Brasil e do Paraguai no contexto internacional na condição de países periféricos em função da dependência econômica da produção de commodities. A partir de revisão de literatura e de análise de relatórios econômicos, contextualiza-se o peso do setor agrícola no PIB de cada país e analisa-se o desempenho de ambos na atual dinâmica da globalização, aprofundando a discussão com as questões relativas ao embate centro-periferia. Por fim, verifica-se que Brasil e Paraguai são dependentes do cenário mundial, regido pelos países que controlam o capitalismo internacional, portanto na condição de periféricos e sem perspectivas de mudança

The politics of crustal faults issues and controversies around the San Ramón Fault in Chile

The seismicity of Chile is mainly controlled by large subduction zones in the Nazca and South American plates’ interface, ca. 150 km from the Chilean coast, which generated the wellknown Mw 9.5 Valdivia (1960) and Mw 8.8 Maule (2010) earthquakes. Besides large subduction events, less-studied crustal earthquakes can cause great destruction due to their shallow hypocentres. Local scientists have indeed paid increasing attention to crustal seismicity, especially after the recent Mw 7.0 Pichilemu (2010) and Mw 6.7 Pisagua (2014) shallow intraplate earthquakes. Although the San Ramón Fault (SRF) is one of the Chilean crustal faults with slower slip rate (ca. 0.3-0.4 mm/yr), it is by far the most popular in the media and amongst politicians. Running for ~30km along the foothills of Santiago, the capital of Chile, the SRF has recently been classified as active, becoming a ‘new’ hazard for nearly 2 million santiaguinos. Moreover, some researchers have estimated that the next occurrence of the up-to-Mw-7.5 earthquakes in the SRF, with an 8000-year recurrence, is geologically imminent (± 500 yr). In this article, we discuss the rise of a conflict around the SRF. The conflict stems from an official narrative about the hazard that the fault represents and the policy (re)actions to this knowledge. We focus on the tensions generated amongst stakeholders (academics, policymakers, privates, and civil society). The discussion includes the scientific disagreement amongst academics regarding the fault’s activity and seismogenic potential, and the political need for action as the SRF hazard becomes word-ofmouth and some stakeholders start demanding disaster risk mitigation. Touching upon disaster risk reduction and urban development issues, the conflict around the SRF unveils the challenges of seismic risk governance in the context of urban and crustal faults

L'impatto della pandemia Covid-19 sulle nuove strutture psichiatrico-forensi in Italia

After the closure of Psychiatric Hospitals (OPs), in 2012 the Italian Government decided to close the High Security Psychiatric Hospitals (OPGs). Law 81/2014 established that each region would provide smaller forensic psychiatry facilities, theREMS (Residence for the Execution of the Security Measures), to accommodate socially dangerous NGRI (Not Guilty by Reason of Insanity) offenders. The main characteristic of a REMS is that it is purely therapeutic and rehabilitative in naturewhile remaining a custodial safety measure. The COVID-19 pandemic undoubtedly tested the organization of these new Italian forensic psychiatry facilities whose practices were not yet fully established, forcing them to ensure patient safety during lockdown amidst the epidemic. The Chapter V Constitutional reform which assigned each region exclusive competence for health policies in its own territory, once the prerogative of the central government, was also put to the test. To assess the impact of the pandemic on the new forensic care system in Italy, we conducted a semi-structured interview with REMS health professionals from various regions with differing levels of contagion: the Poli REMS di Castiglione delle Stiviere; the REMS of Volterra; the REMS of Carovigno and the REMS of Pisticci. The interview assessed how the rehabilitation objectiveshad been met notwithstanding the serious operational limitations consequent to COVID-19 related decisions by the authorities.Dopo la chiusura degli Ospedali Psichiatrici (OP), nel 2012 il Governo Italiano ha deciso di chiudere gli Ospedali Psichiatrici Giudiziari, gli OPG. La legge 81/2014 stabiliva che ogni regione avrebbe dovuto prevedere l’istituzione di strutture psichiatrico-forensi più piccole, le REMS (Residenze per la Esecuzione delle Misure di Sicurezza), per accogliere gli autori di reatonon imputabili, socialmente pericolosi. La caratteristica principale delle REMS è quella di avere una natura prettamente terapeutica e riabilitativa pur rimanendo una misura di sicurezza detentiva. Non c’è dubbio che la pandemia COVID-19 abbia messo alla prova l’organizzazione delle nuove strutture psichiatrico-forensi italiane, con prassi ancora non del tutto consolidate, costringendo le REMS durante il lock-down ad adoperarsi per gestire l’epidemia, garantendo al tempo stesso la sicurezza dei pazienti. In questo contesto è stata messa alla prova anche la riforma del Capitolo V della Costituzione, che assegnava a ciascuna Regione la competenza esclusiva per le politiche sanitarie del proprio territorio, un tempo prerogativa del governo centrale. Alla luce di ciò, per valutare l’impatto della pandemia sul nuovo sistema di assistenza forense in Italia, abbiamo condotto un’intervista strutturata con gli operatori sanitari delle REMS di diverse regioni con diversi livelli di diffusione della malattia: la Poli REMS di Castiglione delle Stiviere; la REMS di Volterra; la REMS di Carovigno e la REMS di Pisticci. L’intervista ha valutato come gli obiettivi riabilitativi fossero stati garantiti nonostante i gravi limiti operativi conseguenti alle decisioni delle autorità determinate dal COVID-19

The value of latissimus dorsi flap with implant reconstruction for total mastectomy after conservative breast cancer surgery recurrence

The presence of previous RT following breast cancer conservative treatment and actual recurrence does not contraindicate breast reconstruction with implant. The use of latissimus dorsi flap together with breast implant provides a large muscle cover to the implant and ideally a low capsular contraction rate. The authors describe a large study in order to have a long follow-up in this group of patients demonstrating the very low capsular contraction rate despite the previous RT