Full scale experiments of a steel portal frame building

While numerous full scale experimental programs have been conducted around the world over the past 50 years to investigate the behaviour of steel portal frame buildings, none have comprehensively investigated the behaviour of such buildings under wind uplift. Wind uplift loads often govern designs in the Australian environment and this became the subject of a recent research project at Queensland University of Technology (OUT). This paper describes the full scale experiments on a steel portal frame building subject to wind uplift, racking and gravity loads. The portal rafter and column members utilised hollow flange beam (HFB) sections [5-8] though the paper's findings on the theoretical and experimental building responses relate to conventional types of steel portal frame buildings.

Fire design rules for load bearing cold-formed steel frame walls exposed to realistic design fire curves

Light gauge Steel Frame (LSF) walls are extensively used in the building industry due to the many advantages they provide over other wall systems. Although LSF walls have been used widely, fire design of LSF walls is based on approximate prescriptive methods based on limited fire tests. Also these fire tests were conducted using the standard fire curve [1] and the applicability of available design rules to realistic design fire curves has not been verified. This paper investigates the accuracy of existing fire design rules in the current cold-formed steel standards and the modifications proposed by previous researchers. Of these the recently developed design rules by Gunalan and Mahendran [2] based on Eurocode 3 Part 1.3 [3] and AS/NZS 4600 [4] for standard fire exposure [1] were investigated in detail to determine their applicability to predict the axial compression strengths and fire resistance ratings of LSF walls exposed to realistic design fire curves. This paper also presents the fire performance results of LSF walls exposed to a range of realistic fire curves obtained using a finite element analysis based parametric study. The results from the parametric study were used to develop a simplified design method based on the critical hot flange temperature to predict the fire resistance ratings of LSF walls exposed to realistic fire curves. Finally, the stud failure times (fire resistance rating) obtained from the fire design rules and the simplified design method were compared with parametric study results for LSF walls lined with single and double plasterboards, and externally insulated with rock fibres under realistic fire curves.

Energy based time equivalent approach to determine the fire resistance ratings of light gauge steel frame walls exposed to realistic design fire curves

Structural fire safety has become one of the key considerations in the design and maintenance of the built infrastructure. Conventionally the fire resistance rating of load bearing Light gauge Steel Frame (LSF) walls is determined based on the standard time-temperature curve given in ISO 834. Recent research has shown that the true fire resistance of building elements exposed to building fires can be less than their fire resistance ratings determined based on standard fire tests. It is questionable whether the standard time-temperature curve truly represents the fuel loads in modern buildings. Therefore an equivalent fire severity approach has been used in the past to obtain fire resistance rating. This is based on the performance of a structural member exposed to a realistic design fire curve in comparison to that of standard fire time-temperature curve. This paper presents the details of research undertaken to develop an energy based time equivalent approach to obtain the fire resistance ratings of LSF walls exposed to realistic design fire curves with respect to standard fire exposure. This approach relates to the amount of energy transferred to the member. The proposed method was used to predict the fire resistance ratings of single and double layer plasterboard lined and externally insulated LSF walls. The predicted fire ratings were compared with the results from finite element analyses and fire design rules for three different wall configurations exposed to both rapid and prolonged fires. The comparison shows that the proposed energy method can be used to obtain the fire resistance ratings of LSF walls in the case of prolonged fires.

Refined Plastic Hinge Analysis of Steel Frame Structures Comprising Non-Compact Sections: I: Formulation

Application of "advanced analysis" methods suitable for non-linear analysis and design of steel frame structures permits direct and accurate determination of ultimate system strengths, without resort to simplified elastic methods of analysis and semi-empirical specification equations. However, the application of advanced analysis methods has previously been restricted to steel frames comprising only compact sections that are not influenced by the effects of local buckling. A concentrated plasticity formulation suitable for practical advanced analysis of steel frame structures comprising non-compact sections is presented in this paper. This formulation, referred to as the refined plastic hinge method, implicitly accounts for the effects of gradual cross-sectional yielding, longitudinal spread of plasticity, initial geometric imperfections, residual stresses, and local buckling.

Adding paths to resilience and daily accounts to an already rich field of inquiry: A brief commentary on James Jackson's "Social structure and health disparities"

In absolute terms, there have been improvements in social resources for all racial and ethnic groups in the United States. The rise in education levels among blacks and Hispanics, for instance, suggests a lessening of the gap between classes, beginning in the later part of the 1960’s (Kao & Thompson, 2003). Yet the divide in income and to a lesser extent education between peoples who differ in gender, skin color and ethnic origin continues and in many ways is greater now than ever (Danziger & Gottschalk, 1997); (Gottschalk, 1997). The psychological distance between those high and those low in social-economic status continues unabated and threatens to undermine the capacity of communities to foster the positive architecture of hope, optimism and equal opportunity that holds us together as a nation...

Analysis of effects of axial shortening of steel columns in frame structure

Steel columns in frame structure always carry heavy upcoming compressive forces. As a consequence, axial shortening becomes a common phenomenon in a multistoried steel structure. A 100 storied steel structure is analyzed in SAP2000 to study the magnitude overall effects of column shortening. It was found from the study that the maximum axial shortening occurs at the columns of top storey of the steel structure and at the columns of bottom storey, the axial deformation is negligible. The increasing rate of axial shortening is significant at the initial levels. However, at the upper levels, the amount of axial shortening in steel columns differs insignificantly. In the selected rigid frame structure, the axial shortening of adjacent steel columns is found to influence significantly the differential shortening of the structure. The consequent effect of differential shortening leads to develop excessive stress in the corner joints which ultimately hamper the normal behavior of the structural systems. The results are discussed elaborately in the paper.

Genome-wide association study identifies eight loci associated with blood pressure

Elevated blood pressure is a common, heritable cause of cardiovascular disease worldwide. To date, identification of common genetic variants influencing blood pressure has proven challenging. We tested 2.5 million genotyped and imputed SNPs for association with systolic and diastolic blood pressure in 34,433 subjects of European ancestry from the Global BPgen consortium and followed up findings with direct genotyping (N 71,225 European ancestry, N 12,889 Indian Asian ancestry) and in silico comparison (CHARGE consortium, N = 29,136). We identified association between systolic or diastolic blood pressure and common variants in eight regions near the CYP17A1 (P = 7 × 10 24), CYP1A2 (P = 1 × 10 23), FGF5 (P = 1 × 10 21), SH2B3 (P = 3 × 10 18), MTHFR (P = 2 × 10 13), c10orf107 (P = 1 × 10 9), ZNF652 (P = 5 × 10 9) and PLCD3 (P = 1 × 10 8) genes. All variants associated with continuous blood pressure were associated with dichotomous hypertension. These associations between common variants and blood pressure and hypertension offer mechanistic insights into the regulation of blood pressure and may point to novel targets for interventions to prevent cardiovascular disease.

A frame-invariant scheme for the geometrically exact beam using rotation vector parametrization

While frame-invariant solutions for arbitrarily large rotational deformations have been reported through the orthogonal matrix parametrization, derivation of such solutions purely through a rotation vector parametrization, which uses only three parameters and provides a parsimonious storage of rotations, is novel and constitutes the subject of this paper. In particular, we employ interpolations of relative rotations and a new rotation vector update for a strain-objective finite element formulation in the material framework. We show that the update provides either the desired rotation vector or its complement. This rules out an additive interpolation of total rotation vectors at the nodes. Hence, interpolations of relative rotation vectors are used. Through numerical examples, we show that combining the proposed update with interpolations of relative rotations yields frame-invariant and path-independent numerical solutions. Advantages of the present approach vis-a-vis the updated Lagrangian formulation are also analyzed.

Partial Loss Of Support And Frame-Soil Interaction

An interaction analysis has been conducted to study the effects of a local loss of support beneath the beam footing of a two-bay plane frame. The results of the study indicate that the magnitude of increase in the bending moment and axial force in the structure due to the presence of a void are dependent, not only on the extent of support loss, but also on the relative stiffnesses between foundation beam and soil, and between superstructure and soil. The increase in bending moment even for a void span of 1/12 of the foundation beam length can become so significant as to exceed the safety provisions. The study shows that the effect of a void on the superstructure moments can be greatly minimized by a combination of rigid foundation and flexible superstructure.

"You must trust somebody" : Valtio, liberalismi ja sotatarviketeollisuus Britanniassa 1884-1905

Tutkielmassa on tarkasteltu Britannian sotilasviranomaisten ja maan sotatarviketeollisuuden välisiä suhteita vuosina 1884-1905. Kiihtyvän kilpavarustelun myötä Britannian sotilasbudjetit kasvoivat nopeasti, mikä johti maan sotatarviketeollisuuden saamien tilausten määrän nopeaan kasvuun samalla kun tuotteiden teknologinen kehitys oli nopeaa. Sotilasmenojen nopea kasvu antoi sotamateriaalihankinnoista vastaaville viranomaisille mahdollisuuden vaikuttaa yksityisen teollisuuden kehitykseen. Keskittämällä tilaukset vain luotettavina pitämilleen yrityksille viranomaiset loivat näiden kanssa puolivirallisia yhteistyösuhteita ja edistivät samalla voimakkaasti alan keskittymistä. Toisaalta muutamien suuryritysten hallitsemasta sotatarviketuotannosta muodostui yksi niistä harvoista teollisuuden aloista, joilla Britannian nopeasti kasvavat kilpailijat eivät pystyneet ohittamaan sitä enempää tuotteiden teknologisessa tasossa kuin markkinaosuuksien suuruudessakaan. Tiettyjen yritysten suosimisen taustalla ei ollut vain maanpuolustuksen kannalta rationaalinen pyrkimys hankkia riittävän laadukasta ja kehittynyttä sotamateriaalia, vaan asiaan vaikutti myös upseerien ja sotilasministeriöiden siviilivirkamiesten perinteiset aristokraattiset ajattelu- ja toimintamallit. Taloudellisen liberalismin hengessä tapahtuneet pyrkimykset uudistaa hankintamenettelyä vastaamaan enemmän vapaan kilpailun ja taloudellisuuden ihanteita jäivät yleensä tuloksettomiksi. Sotamateriaalihankintoihin liittyvä päätöksenteko vaati suurta asiantuntemusta, mikä johti sotaministeriön ja amiraliteetin virkamiesten vaikutusvallan kasvamiseen. Sotateollisuuden laajeneminen kytkeytyy läheisesti 1900-luvun alussa Britannian yhteiskunnallisessa elämässä tapahtuneeseen muutokseen, jota yleensä on luonnehdittu laissez fairen lopuksi. Jo 1880-luvulla alkaneella puuttumisellaan yksityisten sotateollisuusyritysten kehitykseen viranomaiset olivat alkaneet harjoittaa suunniteltua teollisuuspolitiikkaa, jonka tuloksena syntynyt puolivirallinen sotilasteollinen sektori oli aatteellisesti liberaaliin yhteiskuntaan soveltumaton ilmiö. Aseteollisuudessa Britannian valtio oli siten joutunut ensimmäisen kerran läheiseen vuorovaikutussuhteeseen modernien suuryritysten kanssa. Kytkentä, joka 1900-luvun kuluessa levisi yhä uusille aloille samalla kun valtion roolia talouselämässä alettiin vahvistaa. Tutkimuksen varsinaisen lähdemateriaalin muodostavat Britannian parlamentin pöytäkirjat ja sen komiteoiden raportit Niiden ohella on käytetty päätöksien tekemiseen osallistuneiden tai niihin vaikuttamiseen pyrkineiden poliitikkojen ja sotilaiden painettuja puheita, kirjekokoelmia, päiväkirjoja ja muistelmia sekä eräitä aikakauden historiaa koskevia dokumenttikokoelmia ja tilastojulkaisuja. Oleellista valaistusta asiaan tuovat osaltaan aikalaisten kirjoittamat teokset sekä lehdistö, joista kuvastuu ajalle ominainen ajattelutapa. Aihetta suoranaisesti koskevaa, tieteellisen tutkimusten kriteerit täyttävää aikaisempaa tutkimusta on vähän, mutta aihetta sivuavien tutkimusten määrä on erittäin suuri. Sotamateriaalihankintoja ja niiden taustalla olevia syitä voidaan tarkastella niin talous-, sota- aate-, kuin poliittisen historiankin näkökulmista, mutta yksinään mikään niistä ei ole riittävä tämän tutkimuksen kysymyksenasettelun kannalta. Siten tutkielmaa varten on perehdytty laajasti aikakautta koskevaan tutkimuskirjallisuuteen.

Fire resistance of light gauge steel frame wall systems lined with gypsum plasterboards

Light gauge steel frame (LSF) wall systems are increasingly used in residential and commercial buildings as load bearing and non-load bearing elements. Conventionally, the fire resistance ratings of such building elements are determined using approximate prescriptive methods based on limited standard fire tests. However, recent studies have shown that in some instances real building fire time-temperature curves could be more severe than the standard fire curve, in terms of maximum temperature and rate of temperature rise. This has caused problems for safe evacuation and rescue activities, and in some instances has also lead to the collapse of buildings earlier than the prescribed fire resistance. Therefore a detailed research study into the performance of LSF wall systems under both standard fire and realistic fire conditions was undertaken using full scale fire tests to understand the fire performance of different LSF wall configurations. Both load bearing and non-load bearing full scale fire tests were performed on LSF walls configurations which included single layer, double layer, externally insulated wall panels made up of different steel sections and thicknesses of gypsum plasterboards. The non-load bearing fire test results were utilized to understand the factors affecting the fire resistance of LSF walls, while loading bearing fire test results led to development of simplified methods to predict the fire resistance ratings of load bearing LSF walls exposed to both standard and realistic design fires. This paper presents the results of full scale experimental study and highlights the effects of standard and realistic fire conditions on fire performance of LSF walls.

Retinal photography screening programs to prevent vision loss from diabetic retinopathy in rural and urban Australia: A review

Purpose This review assessed the effectiveness of diabetic retinopathy (DR) screening programs, using retinal photography in Australian urban and rural settings, and considered implications for public health strategy and policy. Methods An electronic search of MEDLINE, PubMed, and Embase for studies published between 1 January 1996 and the 30 June 2013 was undertaken. Key search terms were “diabetic retinopathy,” “screening,” “retinal photography” and “Australia.” Results Twelve peer-reviewed publications were identified. The 14 DR screening programs identified from the 12 publications were successfully undertaken in urban, rural and remote communities across Australia. Locations included a pathology collection center, and Indigenous primary health care and Aboriginal community controlled organizations. Each intervention using retinal photography was highly effective at increasing the number of people who underwent screening for DR. The review identified that prior to commencement of the screening programs a median of 48% (range 16–85%) of those screened had not undergone a retinal examination within the recommended time frame (every year for Indigenous people and every 2 years for non-Indigenous people in Australia). A median of 16% (range 0–45%) of study participants had evidence of DR. Conclusions This review has shown there have been many pilot and demonstration projects in rural and urban Australia that confirm the effectiveness of retinal photography-based screening for DR

Obverse side of tombstone of Jeanette Molling (possibly Arthur Molling); Strangriede Cemetery; Hannover Cemeteries Tombs

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Tombstone of Arthur Molling; Strangriede Cemetery (R 26.05); Hannover Cemeteries Tombs

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