320 research outputs found

    Simulation of an 1857-like Mw 7.9 San Andreas Fault Earthquake and the Response of Tall Steel Moment Frame Buildings in Southern California – A Prototype Study

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    In 1857, an earthquake of magnitude 7.9 occurred on the San Andreas fault, starting at Parkfield and rupturing in a southeasterly direction for more than 360 km. Such a unilateral rupture produces significant directivity toward the San Fernando and Los Angeles basins. The strong shaking in the basins due to this earthquake would have had significant long-period content (2-8 s), and the objective of this study is to quantify the impact of such an earthquake on two 18-story steel moment frame building models, hypothetically located at 636 sites on a 3.5 km grid in southern California. End-to-end simulations include modeling the source and rupture of a fault at one end, numerically propagating the seismic waves through the earth structure, simulating the damage to engineered structures and estimating the economic impact at the other end using high-performance computing. In this prototype study, we use an inferred finite source model of the magnitude 7.9, 2002 Denali fault earthquake in Alaska, and map it onto the San Andreas fault with the rupture originating at Parkfield and propagating southward over a distance of 290 km. Using the spectral element seismic wave propagation code, SPECFEM3D, we simulate an 1857-like earthquake on the San Andreas fault and compute ground motions at the 636 analysis sites. Using the nonlinear structural analysis program, FRAME3D, we subsequently analyze 3-D structural models of an existing tall steel building designed using the 1982 Uniform Building Code (UBC), as well as one designed according to the 1997 UBC, subjected to the computed ground motion at each of these sites. We summarize the performance of these structural models on contour maps of peak interstory drift. We then perform an economic loss analysis for the two buildings at each site, using the Matlab Damage and Loss Analysis (MDLA) toolbox developed to implement the PEER loss-estimation methodology. The toolbox includes damage prediction and repair cost estimation for structural and non-structural components and allows for the computation of the mean and variance of building repair costs conditional on engineering demand parameters (i.e. inter-story drift ratios and peak floor accelerations). Here, we modify it to treat steel-frame high-rises, including aspects such as mechanical, electrical and plumbing systems, traction elevators, and the possibility of irreparable structural damage. We then generate contour plots of conditional mean losses for the San Fernando and the Los Angeles basins for the pre-Northridge and modern code-designed buildings, allowing for comparison of the economic effects of the updated code for the scenario event. In principle, by simulating multiple seismic events, consistent with the probabilistic seismic hazard for a building site, the same basic approach could be used to quantify the uncertain losses from future earthquakes

    Interfacing Building Response with Human Behavior Under Seismic Events

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    The goal of this paper is to model the interaction of humans with their built environment during and immediately following a natural disaster. The study uses finite element simulations to evaluate the response of buildings under input ground motions and agent-based dynamic modeling to model the subsequent evacuation of building occupants in the study area immediately following the seismic event. The structural model directly captures building damage and collapse, as well as floor accelerations and displacements to determine nonstructural damage, injuries and fatalities. The goal of this research is to make connections between building damage and occupant injuries, with geographic automata as the information handler for the agent-based platform. This research demonstrates that human behavior and evacuation patterns can be evaluated in the context of realistic structural and nonstructural damage assessments, and that prior knowledge of evacuation patterns is critical for adequate preparedness of cities to severe earthquakes

    Interfacing Building Response with Human Behavior Under Seismic Events

    Get PDF
    The goal of this paper is to model the interaction of humans with their built environment during and immediately following a natural disaster. The study uses finite element simulations to evaluate the response of buildings under input ground motions and agent-based dynamic modeling to model the subsequent evacuation of building occupants in the study area immediately following the seismic event. The structural model directly captures building damage and collapse, as well as floor accelerations and displacements to determine nonstructural damage, injuries and fatalities. The goal of this research is to make connections between building damage and occupant injuries, with geographic automata as the information handler for the agent-based platform. This research demonstrates that human behavior and evacuation patterns can be evaluated in the context of realistic structural and nonstructural damage assessments, and that prior knowledge of evacuation patterns is critical for adequate preparedness of cities to severe earthquakes

    Multi-technical approach for the characterization of polychrome decorative surfaces at Spanish Mission Churches in Nueva Vizcaya (Chihuahua, Mexico)

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    An interdisciplinary and multi-institutional group of science and art conservation specialists has provided new insight into the painting materials used in the polychrome walls and wooden ceilings in four seventeenth century Spanish colonial churches of Nueva Vizcaya (Chihuahua, Mexico). A multi-analytical study of the decorative surfaces was performed in situ using spectroscopic approaches (XRF, FORS), False Colour Infrared Reflectography–IRFC, as well as micro sampling (ATR-FTIR, LM, GC/MS). A survey of natural resources and study (ATR-FTIR, LM) was carried out to elucidate the natural occurrence of a select number of materials in the surrounding areas of the churches. The present paper presents a multi-analytical study and characterization of green, red-orange and black colour pigments and binders selected from the decorative surfaces. The aim of this study is to highlight relationships between local materials and those from the original polychrome ceilings, in order to understand the material and technological influences that converged in the Spanish colonial architecture of northern Mexico

    Relationships between quality of life and family function in caregiver

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    <p>Abstract</p> <p>Background</p> <p>There are caregivers who see their quality of life (QoL) impaired due to the demands of their caregiving tasks, while others manage to adapt and overcome the crises successfully. The influence of the family function in the main caregiver's situation has not been the subject of much evaluation. The aim of this study is to analyse the relationship between the functionality of the family and the QoL of caregivers of dependent relatives.</p> <p>Methods</p> <p>We conducted a cross-sectional study including 153 caregivers. Setting: Two health centers in the city of Salamanca(Spain). Caregiver variables analysed: demographic characteristics, care recipient features; family functionality (Family APGAR-Q) and QoL (Ruiz-Baca-Q) perceived by the caregiver. Five multiple regressions are performed considering global QoL and each of the four QoL dimensions as dependent variables. The Canonical Correspondence Analysis (CCA) was used to study the influence of the family function questionnaire on QoL.</p> <p>Results</p> <p>Family function is the only one of the variables evaluated that presented an association both with global QoL and with each of the four individual dimensions (p < 0.05). Using the CCA, we found that the physical and mental well-being dimensions are the ones which present a closer relationship with family functionality, while social support is the quality dimension that is least influenced by the Family APGAR-Q.</p> <p>Conclusion</p> <p>We find an association between family functionality and the caregiver's QoL. This relation holds for both the global measure of QoL and each of its four individual dimensions.</p

    Drug-resistant tuberculosis patient care journeys in South Africa: A pilot study using routine laboratory data

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    hirteen districts in Eastern Cape (EC), KwaZulu-Natal (KZN) and Western Cape (WC) Provinces, South Africa. OBJECTIVE: To pilot a methodology for describing and visualising healthcare journeys among drug-resistant tuberculosis (DR-TB) patients using routine laboratory records. DESIGN: Laboratory records were obtained for 195 patients with laboratory-detected rifampicin-resistant TB (RR-TB) during July-September 2016. Health facility visits identified from these data were plotted to visualise patient healthcare journeys. Data were verified by facility visits. RESULTS: In the 9 months after the index RR-TB sample was collected, patients visited a mean of 2.3 health facilities (95% CI 2.1-2.6), with 9% visiting ≥4 facilities. The median distance travelled by patients from rural areas (116 km, interquartile range [IQR] 50-290) was greater than for urban patients (51 km, IQR 9-140). A median of 21% of patient's time was spent under the care of primary healthcare facilities: this was respectively 6%, 37% and 39% in KZN, EC and WC. Journey patterns were generally similar within districts. Some reflected a semi-centralised model of care where patients were referred to regional hospitals; other journeys showed greater involvement of primary care
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