Tall concrete buildings subject to vertically moving fires: A case study approach

Fire in buildings can have a severe impact in terms of both human safety and potential economic loss. This is especially true in the case of fires of such severity that the building structure is damaged. Concrete buildings are traditionally regarded as safe in a fire situation as concrete is non-flammable and exhibits highly insulating material properties. The majority of current research relating to the impact of fire on structures examines other forms of construction. Research of concrete in fire is generally limited to investigation and testing of individual members in order to understand the often complex interactions exhibited by concrete as a material at high temperatures. This research seeks to redress the balance by using a systematic approach to examine effects of fire on a holistic concrete structure in simplified but realistic temperature exposures. The research utilises evidence and structural information from the Windsor Tower in Madrid, which suffered a major fire in February 2005 with partial collapse in some areas of the structure. The fire spread throughout the building, travelling both upwards and downwards. Computer modelling was used extensively. Computational Fluid Dynamics (CFD) analysis was used to explore likely fire temperature and duration in localised areas. Structural Finite Element Modelling (FEM) was used to develop a hierarchy of models, beginning with simple structural forms and progressing logically to more detailed structures. This produced a systematic and comprehensive analysis of the reaction of the structure to fire for comparison to the real, observable damage to the building and assessment of generic failure behaviours. The structural model produced was used with a number of variations in support condition, fire spread rate and extent, and fire protection. It was found that for a structure of this type, structural stiffness of the concrete floors was insufficient to compensate for the loss of strength in heated steel members where there was no alternative load redistribution path. It was also found that in the case where an alternative load path exists, but involves steel members which have previously heated during the multiple-floor spread of the fire, the rate of fire spread has a critical effect on the structural stability

In Situ U–Pb Monazite and Xenotime Geochronology of the Abra Polymetallic Deposit and Associated Sedimentary and Volcanic Rocks, Bangemall Supergroup, Western Australia

Abra is a major lead–silver–copper–gold deposit within the Bangemall Supergroup that has a total indicated and inferred resource estimate of 93 million tonnes at 4.0% lead and 10 g/t silver and 14 million tonnes at 0.6% copper and 0.5 g/t gold. The mineralization lies within the upper part of the locally defi ned Gap Well Formation, and in the lower part of the overlying West Creek Formation. These units correlate respectively with the Irregully and lower Kiangi Creek Formations of the Edmund Group.The Abra deposit is characterized by a funnel-shaped brecciated zone, interpreted as a breccia feeder-pipe, overlain by stratabound mineralization made up of the Red Zone, an underlying Black Zone, and a stringer (feeder) zone. The Red Zone is characterized by banded jaspilite, hematite, galena, pyrite, quartz, abundant barite, and siderite. The Black Zone consists of veins and rhythmically banded Pb, Zn, and minor Cu sulfi des, laminated and/or brecciated hematite, magnetite, Fe-rich carbonate, barite, and scheelite.In situ Sensitive high-resolution ion microprobe (SHRIMP) U–Pb geochronology of detrital zircon, monazite, and xenotime in sandstones from the Abra deposit yields a range of dates from c. 2450 Ma to c. 1675 Ma, consistent with results from previous detrital zircon studies. SHRIMP dating of hydrothermal monazite from the Abra deposit suggests that a mineralization event occurred at c. 1385 Ma. The presence of c. 1465 Ma metamorphic/hydrothermal monazite in sandstones from Abra indicates that the host rocks are older and therefore belong to the Edmund Group. SHRIMP geochronology of xenotime extracted from the Tangadee Rhyolite, which outcrops within the lower Kiangi Creek Formation close to the Abra deposit, yields two main age components corresponding to oscillatory-zoned cores and unzoned rims. The cores are interpreted as magmatic in origin and indicate a possible eruption age of c. 1235 Ma, whereas the rims are interpreted to record a later hydrothermal event at c. 1030 Ma. If this interpretation is correct, then the sedimentary succession containing the rhyolite is younger than the Edmund Group (1465 Ma), and may belong to the basal Collier Group (1070 Ma) although the geological setting does not support this

Finding a third archetypal technical system in architectural phenomenology

Within the scope of phenomenology and in order to understand architecture, the role of the technical system is as important as those of the purpose of the building or its form. Mass construction and skeletal construction relate to the architectural theory concepts stereotomy and tectonics respectively, which are suitable for describing the fundamental structural and constructive form of architecture. These two systems became established as man built his first shelters and, so far, represented opposite sides of the building industry’s possibilities. The development of new construction techniques and the relationship between research and technology have a great impact on architecture, although new processing methods and materials may not necessarily cause genuine tectonic changes. The technical dimension of architecture is analysed in this work describing how technical elements are built from materials, and then organised in systems. First, the paper examines the division of technical systems in two categories (massive systems and skeletal systems); then it studies timber’s modern production technologies and subsequently the paper critically analyses how these influence the architectural form. The paper concludes that a third archetypal technical system can be perceived with the assembly of surface elements, joining both the multifunctional aspect of the massive systems and the flexibility of the skeletal systems, this third category being fundamental in phenomenological terms

Methods of Multivariable Earthquake Precursor Analysis and a Proposed Prototype Earthquake Early Warning System

Significant advances are being made in earthquake prediction theory; however, a reliable method for forecasting the occurrence of earthquakes from space and/or ground based technologies remains limited to no more than a few minutes before the event happens. Several claims of earthquake precursors have been put forward, such as ionospheric changes, electromagnetic effects, and ground heating, though the science behind these is far from complete and the successful application of these precursors is highly regionally variable. Existing and planned dedicated space missions for monitoring earthquake precursors are insufficient for resolving the precursor issue. Their performance does not satisfy the requirements of an earthquake early warning system in terms of spatial and temporal coverage. To achieve statistically significant validation of precursors for early warning delivery, precursor data must be obtained from simultaneous repeated monitoring of several precursors in focus regions over a long period of time and then integrated and processed. Data sources include historical data, data from ground-based units, airborne systems, and space-based systems. This paper describes methods of systematic evaluation of regionally specific, multivariable precursor data needed for the identification of the expected time, magnitude and the position of the epicentre. This data set forms the basis for a proposed operational early warning system developed at the International Space University and which is built in partnership with local and national governments as well as international organizations

Performance of concrete in fire: a review of the state of the art, with a case study of the windsor tower fire

This paper provides a “State of the Art” review on current research into the effects of fire exposures upon concrete. The principal influences of high temperature in concrete are loss of compressive strength and spalling, the forcible ejection of material from a member. Though a lot of information has been gathered on both phenomena, there remains a need for a broader understanding of the response of concrete structures to different heating regimes and the performance of complete concrete structures subjected to realistic fire exposures. There is a lack of information derived from large-scale tests on concrete buildings in natural fires. Besides undertaking further fire tests, lessons can also be learnt from real fires and the University of Edinburgh has embarked upon detailed studies of the serious fire in the Windsor Tower, Madrid. In order to properly characterise the fire and the performance of the structure a data-gathering exercise has been undertaken and computer modelling tools are being applied in order to obtain better insights into the structural response. There remains some uncertainty about the precise mechanism of fire spread, but an external route is likely, facilitated to some degree by the glazed curtain walling construction; lack of fire protection on the steelwork was the major reason for the subsequent partial collapse of the upper floors and the localised failure of a concrete portal frame can be attributed to the same reason

Safety and immunogenicity of boosting BCG vaccinated subjects with BCG: comparison with boosting with a new TB vaccine, MVA85A.

OBJECTIVES: To investigate the safety and immunogenicity of a booster BCG vaccination delivered intradermally in healthy, BCG vaccinated subjects and to compare with a previous clinical trial where BCG vaccinated subjects were boosted with a new TB vaccine, MVA85A. DESIGN: Phase I open label observational trial, in the UK. Healthy, HIV-negative, BCG vaccinated adults were recruited and vaccinated with BCG. The primary outcome was safety; the secondary outcome was cellular immune responses to antigen 85, overlapping peptides of antigen 85A and tuberculin purified protein derivative (PPD) detected by ex vivo interferon-gamma (IFN-gamma) ELISpot assay and flow cytometry. RESULTS AND CONCLUSIONS: BCG revaccination (BCG-BCG) was well tolerated, and boosting of pre-existing PPD-specific T cell responses was observed. However, when these results were compared with data from a previous clinical trial, where BCG was boosted with MVA85A (BCG-MVA85A), MVA85A induced significantly higher levels (>2-fold) of antigen 85-specific CD4+ T cells (both antigen and peptide pool responses) than boosting with BCG, up to 52 weeks post-vaccination (p = 0.009). To identify antigen 85A-specific CD8+ T cells that were not detectable by ex vivo ELISpot and flow cytometry, dendritic cells (DC) were used to amplify CD8+ T cells from PBMC samples. We observed low, but detectable levels of antigen 85A-specific CD8+ T cells producing IFNgamma (1.5% of total CD8 population) in the BCG primed subjects after BCG boosting in 1 (20%) of 5 subjects. In contrast, in BCG-MVA85A vaccinated subjects, high levels of antigen 85A-specific CD8+ T cells (up to 14% total CD8 population) were observed after boosting with MVA85A, in 4 (50%) of 8 subjects evaluated. In conclusion, revaccination with BCG resulted in modest boosting of pre-existing immune responses to PPD and antigen 85, but vaccination with BCG-MVA85A induced a significantly higher response to antigen 85 and generated a higher frequency of antigen 85A-specific CD8+ T cells. TRIAL REGISTRATION: ClinicalTrials.gov NCT00654316 NCT00427830

Model-based analysis of a concrete building subjected to fire

Draft paper: to be presented at Advanced Research Workshop on Fire Computer Modelling, Santander, Spain, 19 October 2007A case study is presented of the Windsor Tower fire in Madrid, a mainly concrete-framed office block, which was involved in a major, multiple floor fire in February 2005. The performance of the structure is documented and examined using all available methods, including analysis of data on the fire and computer modelling of the fire and structure. Holistic structural performance during a fire is more complex than the effects of fire upon individual members which make up the structure. In concrete structures, fire conditions can have a variety of structural effects, both positive and negative, beyond the deterioration of the mechanical properties of the material. In order to properly understand the performance of concrete buildings, comprehensive models, which account for all relevant factors, are required. One of the key challenges is the limited data available from well-instrumented full-scale tests on whole concrete structures, compared to the large amount of data on the behaviour of individual concrete members and the large number of experiments carried out on steel and composite steel/concrete structures. Here, a systematic approach is adopted for modelling, building up from fundamental, but simplified, analyses. The fire conditions have been computed using simplified analyses and Computational Fluid Dynamic (CFD) modelling. Similarly, the thermal and mechanical response of the structure is assessed using simplified analyses and Finite Element Method (FEM) modelling. The CFD simulations provide the fire exposure histories of the structural members. The FEM calculations have examined the structural effects of changes to the concrete properties due to increased temperature. Extrapolation of results can examine redundancies within a building and their mobilisation to prevent collapse of the structure in the case of fire. The paper gives an introduction to the Windsor Tower structure, the fire itself and further details of the methods used in modelling the fire and structural response. Model sizing, structural properties and failure modes are discussed along with initial analysis

Socio-economic benefits of using space technologies to monitor and respond to earthquakes

Earthquakes represent a major hazard for populations around the world, causing frequent loss of life, human suffering and enormous damage to homes, other buildings and infrastructure. The Technology Resources for Earthquake Monitoring and Response (TREMOR) Team of 36 space professionals analysed this problem over the course of the International Space University Summer Session Program and published their recommendations in the form of a report. The TREMOR Team proposes a series of space- and ground-based systems to provide improved capability to manage earthquakes. The first proposed system is a prototype earthquake early-warning system that improves the existing knowledge of earthquake precursors and addresses the potential of these phenomena. Thus, the system will at first enable the definitive assessment of whether reliable earthquake early warning is possible through precursor monitoring. Should the answer be affirmative, the system itself would then form the basis of an operational earlywarning system. To achieve these goals, the authors propose a multi-variable approach in which the system will combine, integrate and process precursor data from space- and ground-based seismic monitoring systems (already existing and new proposed systems) and data from a variety of related sources (e.g. historical databases, space weather data, fault maps). The second proposed system, the prototype earthquake simulation and response system, coordinates the main components of the response phase to reduce the time delays of response operations, increase the level of precision in the data collected, facilitate communication amongst teams, enhance rescue and aid capabilities and so forth. It is based in part on an earthquake simulator that will provide pre-event (if early warning is proven feasible) and post-event damage assessment and detailed data of the affected areas to corresponding disaster management actors by means of a geographic information system (GIS) interface. This is coupled with proposed mobile satellite communication hubs to provide links between response teams. Business- and policy-based implementation strategies for these proposals, such as the establishment of a non-governmental organisation to develop and operate the systems, are included

Effect of vaccine dose on the safety and immunogenicity of a candidate TB vaccine, MVA85A, in BCG vaccinated UK adults.

PURPOSE: A non-randomised, open-label, Phase I safety and immunogenicity dose-finding study to assess the safety and immunogenicity of the candidate TB vaccine Modified Vaccinia virus Ankara expressing Antigen 85A (MVA85A) from Mycobacterium tuberculosis (MTB) in healthy adult volunteers previously vaccinated with BCG. METHODS: Healthy BCG-vaccinated volunteers were vaccinated with either 1×10(7) or 1×10(8)PFU of MVA85A. All adverse events were documented and antigen specific T cell responses were measured using an ex vivo IFN-γ ELISPOT assay. Safety and immunogenicity were compared between the 2 dose groups and with a previous trial in which a dose of 5×10(7)PFU MVA85A had been administered. RESULTS: There were no serious adverse events recorded following administration of either 1×10(7) or 1×10(8)PFU of MVA85A. Systemic adverse events were more frequently reported following administration of 1×10(8)PFU of MVA85A when compared to either 5×10(7) or 1×10(7)PFU of MVA85A but were mild or moderate in severity and resolved completely within 7 days of immunisation. Antigen specific T cell responses as measured by the IFN-γ ELISPOT were significantly higher following immunisation in adults receiving 1×10(8)PFU compared to the 5×10(7) and 1×10(7) doses. Additionally, a broader range of Ag85A epitopes are detected following 1×10(8)PFU of MVA85A. CONCLUSION: A higher dose of 1×10(8)PFU of MVA85A is well-tolerated, increases the frequency of IFN-γ secreting T cells detected following immunisation and broadens the range of Ag85A epitopes detected

Non-compliance with clinical guidelines increases the risk of complications after primary total hip and knee joint replacement surgery

Background Total hip and total knee replacement (THR/TKR) are common and effective surgeries to reduce the pain and disability associated with arthritis but are associated with small but significant risks of preventable complications such as surgical site infection (SSI) and venous-thrombo-embolism (VTE). This study aims to determine the degree to which hospital care was compliant with clinical guidelines for the prevention of SSI and VTE after THR/TKR; and whether non-compliant prophylaxis is associated with increased risk of complications. Methods and findings A prospective multi-centre cohort study was undertaken in consenting adults with osteoarthritis undergoing elective primary TKR/THR at one of 19 high-volume Australian public or private hospitals. Data were collected prior to surgery and for one-year post-surgery. Four adjusted logistic regression analyses were undertaken to explore associations between binary non-compliance and the risk of surgical complications: (1) composite (simultaneous) non-compliance with both (VTE and antibiotic) guidelines and composite complications [all-cause mortality, VTE, readmission/reoperation for joint-related reasons (one-year) and non-joint-related reasons (35-days)], (2) VTE non-compliance and VTE outcomes, (3) antibiotic non-compliance and any SSI, and (4) antibiotic non-compliance and deep SSI. Data were analysed for 1875 participants. Guideline non-compliance rates were high: 65% (VTE), 87% (antibiotics) and 95% (composite guideline). Composite non-compliance was not associated with composite complication (12.8% vs 8.3%, adjusted odds ratio [AOR] = 1.41, 95%CI 0.68–3.45, p = 0.40). Non-compliance with VTE guidelines was associated with VTE outcomes (5% vs 2.4%, AOR = 2.83, 95%CI 1.59–5.28,p < 0.001). Non-compliance with antibiotic guidelines was associated with any SSI (14.8% vs 6.1%, AOR = 1.98, 95%CI 1.17–3.62,p = 0.02) but not deep infection (3.7% vs 1.2%,AOR = 2.39, 95%CI 0.85–10.00, p = 0.15). Conclusions We found high rates of clinical variation and statistically significant associations between non-compliance with VTE and antibiotic guidelines and increased risk of VTE and SSI, respectively. Complications after THR/TKR surgery may be decreased by improving compliance with clinical guidelines