Damping capacity of a model steel structure

The damping capacities of seven model steel structures, each consisting of a heavy steel platform supported on four columns, have been determined from forced vibration tests. The vibrations were produced by an eccentric-mass vibration generator, and the amplitudes ranged from small displacements up to slightly greater than yield displacement. The tests were terminated at the higher amplitudes once fatigue cracks formed in any of the joint welds in the columns. For vibration amplitudes up to a critical amplitude slightly less than yield displacement, the damping factors of the structures were constant, independent of amplitude, and ranged between .15 and .25~ for different structures. At vibration amplitudes greater than the critical amplitude, the damping factors of the structures became functions of amplitude. For example, the damping factor of one test structure increased from .15 to 1.~ as the displacement amplitude increased from 1.1 to 1.4 inches. The last structure tested revealed that a few cycles of vibration at amplitudes greater than the critical amplitude would increase these values slightly. Finally, the results summarized above are compared with the results of: {i) experimental work conducted by Lazan; {ii) reversed loading tests conducted on cantilever beams of similar construction to those tested in the work described in this report; and (iii) experimental work conducted by Hanson

What Works for Aboriginal and Torres Strait Islander Men? A Systematic Review of the Literature

Aboriginal and Torres Strait Islander men experience significantly higher rates of suicide, trauma, alcohol related deaths and unemployment than other Australian men. Despite significant levels of government intervention, rates of family violence, unemployment and incarceration continue to increase in Aboriginal and Torres Strait Islander communities. As a subset of the Aboriginal and Torres Strait Islander population, there has been a lesser focus on how to meaningfully improve the wellbeing of Aboriginal and Torres Strait Islander men. This systematic review seeks to understand what interventions, programs and activities are successful in improving the wellbeing of Aboriginal and Torres Strait Islander men and thereby the wellbeing of their communities. A thorough search of the literature was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Fifteen studies met the inclusion criteria. Analysis of the programs, activities and interventions evaluated in these studies indicated two prominent themes that were successful in improving the wellbeing of Aboriginal and Torres Strait Islander men: strengthening identity and increasing social connection. The mechanisms contributing to these outcomes are discussed, as are implications for policy and future research

The dynamic behavior of steel frame and truss buildings

This report describes experimental and analytical studies of the dynamic behavior of the East Building of the University of California\u27s new Medical Center at San Francisco, California. It also describes experimental tests conducted on the East Building\u27s mechanical service tower and on an adjacent elevator tower. Experimental tests on the East Building were conducted in the summers of 1964 and 1965. Vibrations were produced by eccentric-masstype vibration generators. Frequency responses, time responses, and mode shapes were observed. In the summer 1964 tests, the first mode east-west had 2% of critical damping and the first mode north-south had 1.8%; the values of damping for the higher modes lay in the range 0.4% to 0.9% of critical In the summer 1965 tests, the damping capacity measurements were mostly in the range 5 to 10% of critical. The cause of this increase in damping capacity was investigated in the fall 1965 tests. The fall 1965 tests showed that although the East Building was designed as free-standing, it was dynamically coupled to its adjacent buildings The relatively large damping capacity of this coupled system has been attributed to the Coulomb damping provided by non-structural connections between buildings An analytical model of the East Building was formulated to provide behavior corresponding to the summer 1964 test results. A standard openframe- type model was found capable of representing the dynamic behavior of the real structure. The analytical model was subjected to the El Centro earthquake ground acceleration record in a digital computer analysis. With 5% critical damping in the first few modes, no members of the frame yielded, but when the intensity of the earthquake was increased by a factor of 1.3, some members did yield

Peat Bog Ecosystems: Weathering, Erosion and Mass Movement of Blanket Bog

When the protective living layer of the acrotelm of a peat bog is lost as a result of human activities, the catotelm peat beneath becomes subject to weathering and erosion. As much as 3 cm thickness can be lost in one year. More spectacular losses can occur if mass movement of the peat occurs because the stability of the peat on a hill-slope is compromised by the same factors as those which trigger erosion. With the recent reduction in human pressures on blanket bog landscapes, there is evidence of natural re-vegetation across many areas, although very extensive areas continue to erode. This briefing note is part of a series aimed at policy makers, practitioners and academics to help explain the ecological processes that underpin peatland function. Understanding the ecology of peatlands is essential when investigating the impacts of human activity on peatlands, interpreting research findings and planning the recovery of damaged peatlands

Peat Bog Ecosystems: Burning

Fires occur naturally on bogs through lightning strikes, but for any given location this is a rare occurrence - perhaps once every 200 or 300 years. Current burning practice for grazing or to encourage grouse means that ground is burnt 10x more frequently than this, resulting in loss of natural peat bog biodiversity and peat-forming species. Full recovery may take considerably more than a century. This briefing note is part of a series aimed at policy makers, practitioners and academics to help explain the ecological processes that underpin peatland function. Understanding the ecology of peatlands is essential when investigating the impacts of human activity on peatlands, interpreting research findings and planning the recovery of damaged peatlands

Peat Bog Ecosystems: Grazing and Trampling

Bog vegetation is sensitive to trampling and thus is only able to sustain a combination of domestic and wild grazing stock at very low densities. Higher densities combine with impacts such as burning, drainage and atmospheric pollution to cause loss of the protective bog vegetation and development of erosion complexes. Trampling is also an issue for researchers repeatedly visiting monitoring locations, even if only once a year. This briefing note is part of a series aimed at policy makers, practitioners and academics to help explain the ecological processes that underpin peatland function. Understanding the ecology of peatlands is essential when investigating the impacts of human activity on peatlands, interpreting research findings and planning the recovery of damaged peatlands

Peat Bog Ecosystems: Domestic peat extraction

Small-scale peat extraction for fuel has probably been a feature of peat-dominated landscapes for many thousands of years. The cumulative scale and extent of this activity is often under-estimated, particularly in areas which are now remote parts of the landscape. A cut peat face acts as a one-sided drain and thus has a number of hydrological and morphological effects, including potentially the creation of weak zones within the peat which may trigger mass movement. This briefing note is part of a series aimed at policy makers, practitioners and academics to help explain the ecological processes that underpin peatland function. Understanding the ecology of peatlands is essential when investigating the impacts of human activity on peatlands, interpreting research findings and planning the recovery of damaged peatlands

Peat Bog Ecosystems: Tracks across peatlands

Tracks have been made across peatlands for as long as human society has existed. Un-made tracks (i.e. those created simply by regular use, with no construction involved) were probably first created by grazing animals and then presumably also used by early human communities. Finding these increasingly impassable with regular use, human societies began to construct 'corduroy roads' during Neolithic, Bronze and Iron Age times. These first constructed tracks were made from cut timbers(below). Across Europe, many examples of these corduroy roads have been found preserved in lowland bogs, perhaps most famously in the Somerset Levels and more recently at Hatfield Moors on the Humberhead Levels

Peat Bog Ecosystems: Structure, Form, State and Condition

This briefing note is part of a series aimed at policy makers, practitioners and academics to help explain the ecological processes that underpin peatland function. Understanding the ecology of peatlands is essential when investigating the impacts of human activity on peatlands, interpreting research findings and planning the recovery of damaged peatlands. This report considers the structure, form, state and condition of bogs/mires. It recommends use of the JNCC '-tope' system in describing peat areas, which encompasses vegetation, microtopography and overal site hydrology, rather than only on vegetation description

TURAS Multidisciplinary urban landscape design guidelines: Poplar HARCA - Carradale House

Transitioning Towards Urban Resilience and Sustainability (TURAS) is a European-wide research and development programme. The “TURAS” project aims to bring together urban communities, researchers, local authorities and SMEs to research, develop, demonstrate and disseminate transition strategies and scenarios to enable European cities and their rural interfaces to build vitally-needed resilience in the face of significant sustainability challenges. To ensure maximum impact, the TURAS project has developed an innovative twinning approach bringing together decision makers in local authorities with SMEs and academics to ensure meaningful results and real change are implemented over the duration of the project. Eleven local authorities or local development agencies are involved as partners in the project and they will orient research and development from the outset towards the priority sustainability and resilience challenges facing their cities. Nine leading academic research institutions and six SMEs will work with these cities helping them to reduce their urban ecological footprint through proposing new visions, feasibility strategies, spatial scenarios and guidance tools to help cities address these challenges. The specific challenges addressed in TURAS include: climate change adaptation and mitigation; natural resource shortage and unprecedented urban growth. Over the five year duration of the project, the feasibility of these new approaches will be tested in selected case study neighbourhoods. One of these potential neighbourhoods is the redevelopment of the Poplar HARCA housing estate site known as Aberfeldy Village in Bromley-by-Bow, East London (http://www.turas-cities.org/urban_regions/London/en/csa/51). The following report comprises guidelines on a multidisciplinary approach to landscape design for transitioning the Poplar HARCA estate into a new sustainable community