Experimental investigation of the cyclic behaviour of unreinforced masonry spandrels

In unreinforced masonry (URM) walls the vertical piers are connected by horizontal spandrel elements. Numerical simulations have shown that spandrels influence significantly the global wall behaviour under seismic loading. Despite their importance, experimental data on the cyclic behaviour of these spandrels is very scarce. The lack of experimental data prevented in the past the validation of numerical and mechanical models regarding the cyclic behaviour of masonry spandrels. For this reason a research program was initiated in which the cyclic behaviour of masonry spandrels was investigated experimentally and numerically. Within this program different configurations of masonry spandrels were tested under quasi-static monotonic and cyclic loading. The spandrel configurations that were investigated included pure masonry spandrels and masonry spandrels which also comprise a reinforced concrete (RC) beam or slab. The latter represents spandrels in newer masonry buildings with RC slabs or RC ring beams while the former can be found in older masonry buildings. This paper presents preliminary results of the experimental program as well as some selected results of the accompanying numerical study

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

STR-843: CARACTÉRISATION DE LA MAÇONNERIE DE PIERRES POUR L’ÉVALUATION SISMIQUE DE BÂTIMENTS PATRIMONIAUX

L’évaluation de la résistance sismique des bâtiments patrimoniaux en maçonnerie de pierres non armée (MNA) est la première étape nécessaire à l’évaluation du risque sismique associé et l\u27élaboration d\u27une stratégie de réhabilitation optimale tout en conservant les caractéristiques de l\u27architecture d\u27origine. L’évaluation de la résistance latérale des murs en MNA est complexifiée par le fait qu’ils sont souvent composés de deux ou trois parois de matériaux aux propriétés variables, et leur résistance aux charges sismiques est compromise par la dégradation des joints de mortier. Dans l\u27Est du Canada, les caractéristiques des murs porteurs des bâtiments patrimoniaux, telles que leur composition, l’agencement des composantes et leurs matériaux, sont peu connues. De plus, les propriétés mécaniques de ses murs en MNA ont fait l’objet de très peu de recherches, rendant difficile la prédiction fiable de leur résistance sismique d’autant plus que les modèles actuels de prédiction de résistance latérale des murs en MNA nécessitent les valeurs de résistances à la compression et au cisaillement spécifiques au site. Cet article présente une évaluation expérimentale des paramètres de résistance à la compression et au cisaillement d’assemblages en maçonnerie de pierre calcaire et de mortier de ciment et chaux. On détaille le plan d’expérimentation, l’analyse et la discussion des résultats incluant : la résistance à la compression des mortiers de chaux et des blocs de pierre calcaire, le comportement force-déplacement en compression d’assemblage de maçonnerie, la résistance au cisaillement de joint et la résistance à la flexion du joint

ANALYTICAL DISPLACEMENT-BASED SEISMIC FRAGILITY ANALYSIS OF STONE MASONRY BUILDINGS

Abstract. In an effort to reduce seismic risks, the Geological Survey of Canada has recently taken important steps by initiating a project on quantitative assessment of earthquake related risks. One of the objectives of this project is to Ahmad Abo-El-Ezz, Marie-José Nollet, Miroslav Nastev 2 INTRODUCTION Majority of existing historic buildings in old urban centers in Eastern Canada are stone masonry structures and represent un-measurable architectural and cultural heritage. Historic stone masonry buildings were built to resist gravity loads only and generally offer poor resistance to lateral seismic loads. Damage occurred to stone masonry buildings from past earthquakes is attributed to inadequate structural integrity due to the lack of connection between stone masonry structural walls and wooden floors and roofs; and to ensuing inadequate structural resistance, which results into typical shear cracking and disintegration of stone walls and partial or total collapse of buildings The high seismic risks related to stone masonry buildings are even more increased due to their location in densely populated urban centers in a way that the consequences of failure of these structures tend to be severe with regards to human casualties, heritage damage and economic losses In an effort to reduce seismic risks, the Geological Survey of Canada has recently taken important steps by initiating a project on quantitative assessment of earthquake related risks. One of the objectives of this project is to study the seismic vulnerability of historic stone masonry buildings. The old historic center of Quebec City was selected as a typical study area. Seismic risk is often considered as the convolution of seismic hazard (expected ground motion at given location), exposure (demographics, buildings, essential facilities, utilities, etc.), and vulnerability (response of structures to earthquake impacts, generally defined by expected degree of damage under different levels of seismic loading). These three components are integrated to determine direct and indirect physical damage and losses. Fragility analysis is the key component in performance based seismic risk assessment. It provides the link between the two other components of the seismic risk assessment process, inventory and seismic hazard. The most widely used risk assessment tool in North America, Hazus-MH [3], seems to not adequately represent the response of stone masonry structures to earthquake loading. It considers only one structural class for unreinforced masonry buildings, URM, mainly covering brittle brick masonry structures. The European ELER tool The objective of this paper is to introduce a procedure for the development of displacement based fragility curves for typical stone masonry buildings in Old Quebec City and to present the generated results. It was first necessary to make an inventory of the existing masonry buildings and to include their special structural and material characteristics. At the end, a comparison is made with fragility curves implicit in Hazus and ELER seismic risk assessment tools in order to assess differences and the potential disparities they may exert on damage probability estimates

Vulnerability Assessment of Seismic Induced Out-of-Plane Failure of Unreinforced Masonry Wall Buildings

Damage to unreinforced masonry (URM) buildings from earthquake shaking is often caused by out-of-plane failure of walls. This is particularly relevant to the majority of URM buildings in Eastern Canada that were constructed prior to the introduction of seismic design prescriptions. Seismic vulnerability assessment of this type of failure is therefore an essential step towards seismic risk mitigation. This paper presents a simplified procedure for seismic vulnerability assessment of out-of-plane failure of URM wall buildings. The procedure includes the development of an equivalent single degree of freedom model of the wall with a characteristic force-deformation capacity curve. The capacity curve is convolved with displacement response spectrum to predict the displacement demand. The predicted displacement demand is compared to displacement thresholds criteria corresponding to the initiation of each damage state. The procedure is applied to an inventory of URM buildings in Montreal and the corresponding probability of out-of-plane damage is evaluated.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Analyse de la vulnérabilité sismique hors-plan des bâtiments de maçonnerie de pierre de l’Est canadien : Application aux bâtis du Vieux-Québec et du Vieux-Montréal

Les courbes de fragilité se révèlent être un outil performant pour l’évaluation de la vulnérabilité sismique de bâtiments construits en maçonnerie de pierre tels que ceux qu’on retrouve dans les quartiers historiques des villes de l’Est canadien. Cependant, la plupart ne considèrent pas les possibilités d’effondrement dans la direction hors-plan. Ce mode de rupture peut s’avérer critique pour des éléments tels que les cheminées, les murs coupe-feu ou les murs de façades. La présente étude porte sur l'évaluation de la vulnérabilité sismique de bâtiments en maçonnerie de pierre sensibles à la rupture hors-plan. Un modèle de capacité hors-plan faisant apparaître des degrés de dommage en terme de déplacement et une méthode de calcul des déplacements dans la direction hors-plan tenant compte de l’effet de filtre du bâtiment dans la direction du plan ont été développés. Les courbes de fragilité obtenues permettent d’estimer la probabilité de dommage pour différents scénarios sismiques.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Earthquake Magnitude and Shaking Intensity Dependent Fragility Functions for Rapid Risk Assessment of Buildings

An integrated web application, referred to as ER2 for rapid risk evaluator, is under development for a user-friendly seismic risk assessment by the non-expert public safety community. The assessment of likely negative consequences is based on pre-populated databases of seismic, building inventory and vulnerability parameters. To further accelerate the computation for near real-time analyses, implicit building fragility curves were developed as functions of the magnitude and the intensity of the seismic shaking defined with a single intensity measure, input spectral acceleration at 1.0 s implicitly considering the epicentral distance and local soil conditions. Damage probabilities were compared with those obtained with the standard fragility functions explicitly considering epicentral distances and local site classes in addition to the earthquake magnitudes and respective intensity of the seismic shaking. Different seismic scenarios were considered first for 53 building classes common in Eastern Canada, and then a reduced number of 24 combined building classes was proposed. Comparison of results indicate that the damage predictions with implicit fragility functions for short (M ≤ 5.5) and medium strong motion duration (5.5 < M ≤ 7.5) show low variation with distance and soil class, with average error of less than 3.6%

FireLossRate: An R package to estimate the loss rate of residential structures affected by wildfires at the Wildland Urban Interface

To inform proactive management actions supporting community resilience to wildfires, we developed a new software package called FireLossRate. This package in R helps the user to compute wildfire impacts on residential structures at the Wildland Urban Interface (WUI). The package integrates spatial information about exposed structures, empirical equations that estimate the loss rate of structures affected by wildfires as a function of fireline intensity and distance from fire edge with fire growth modeling outputs from fire simulation software and burn probability models. FireLossRate helps to quantify and produce spatially explicit data on structural exposure and loss for single and multiple fires. The package automates post hoc analyses on simulations that include single or multiple wildfires and enables result mapping when combined with other packages available in R. In this paper, we describe the functionality of the FireLossRate package and introduce users to the interpretation of impact indicators of wildfires at the WUI. FireLossRate is available for download at https://github.com/LFCFireLab/FireLossRate. • FireLossRate allows the computation of wildfire impacts indicators on residential structures at the Wildland Urban Interface in support of community fire risk management