Scottish landform examples 45: Sgriob na Caillich: a landslide-sourced medial moraine on the Isle of Jura

ABSTRACT

Medial moraines deposited by former glaciers and ice sheets are rare in Scotland. The most prominent example is the Sgriob na Caillich moraine, which consists of two to four parallel belts of angular quartzite boulders that extend northwestwards for over 3.5?km from the SW flank of Beinn an Oir on the Isle of Jura. The boulder belts extend to within 300?m of the present coastline, where they are truncated by a low bluff and raised marine terrace. The source of the moraine coincides with bedrock gullies and cliffs that represent the scars of former rock-slope failure(s), indicating that the moraine debris was sourced by one or more rockfalls or rockslides onto the ice surface after Beinn an Oir had emerged from the thinning ice cover as a nunatak. Exposure dating of boulders on the moraine indicate that it formed at 16.6?±?0.8?ka, consistent with the timing of ice-sheet retreat in this sector. The alignment of the moraine indicates ice-margin retreat to the SE; as regional ice-sheet retreat across the adjacent offshore shelf was to the NE, this anomaly implies that a residual icefield became stranded on Jura during ice-sheet retreat.     

MODELLING OF RC BEAM-COLUMN JOINTS AND STRUCTURAL WALLS

The deformation of beam-column joints may contribute significantly to drift of reinforced concrete (RC) frames. In addition, failure may occur in the joints due to cumulative concrete crushing from applied beam and column moments, bond slip of embedded bars or shear failure as in the case of existing frames with nonductile detailing. When subjected to earthquake loading, failure in RC structural wall is similar to failure of frame joints as it may occur due to cumulative crushing from high flexural stresses, bond slip failure of lap splice, shear failure or a combination of various mechanisms of failure. It is important to include these behavioural characteristics in a simple model that can be used in the analysis of RC frames and RC walls to predict their response under earthquake loading and determine their failure modes.

Global macro models for the beam-column joint and for RC structural walls are developed. The proposed models represent shear and bond slip deformations as well as flexural deformations in the plastic hinge regions. The models are capable of idealising the potential failure mechanism due to crushing of concrete, bond slip or shear with allowance for the simultaneous progress in each mode. The model predictions are compared with available experimental data and good correlation is observed between analytical results and the test measurements.     

Natural and Unnatural Disasters: Responding with Respect for Indigenous Rights and Knowledges

A key challenge for contemporary democratic societies is how to respond to disasters in ways that foster just and sustainable outcomes that build resilience, respect human rights, and foster economic, social, and cultural well‐being in reasonable timeframes and at reasonable costs. In many places experiencing rapid environmental change, indigenous people continue to exercise some level of self‐governance and autonomy, but they also face the burden of rapid social change and hostile or ambiguous policy settings. Drawing largely on experience in northern Australia, this paper argues that state policies can compound and contribute to vulnerability of indigenous groups to both natural and policy‐driven disasters in many places. State‐sponsored programmes that fail to respect indigenous rights and fail to acknowledge the relevance of indigenous knowledge to both social and environmental recovery entrench patterns of racialised disadvantage and marginalisation and set in train future vulnerabilities and disasters. The paper advocates an approach to risk assessment, preparation, and recovery that prioritises partnerships based on recognition, respect, and explicit commitment to justice. The alternatives are to continue prioritising short‐term expediencies and opportunistic pursuit of integration, or subverting indigenous rights and the knowledge systems that underpin them. This paper argues such alternatives are not only unethical, but also ineffective.     

Partisanship,policy entrepreneurs and the market for ideas: what we can learn from policy failure

ABSTRACT

The Office of Living Victoria (OLV), was established in 2011 by the then Liberal-National Party Coalition Government. It was created in response to a water crisis and intended to revolutionise water management and delivery, challenging established authorities and practices consolidated under the previous Labor government in Victoria. There was a decidedly partisan motivation for its conception. The drive for new ideas and innovation created opportunities for policy entrepreneurs who won the competition against more conventional research advocacy, and determined the agenda of the new agency, in the process curbing an existing policy network. Yet within a short period, this initiative was mired in scandal, and ended in 2014 having failed to achieve its purposes. This article explores this instance of policy failure, assessing the policy trajectory of the OLV in relation to the concepts of partisanship, policy entrepreneurship, and policy networks.     

The trials and travails of the Islamic State in Pakistan

While Pakistan is in many ways an ideal location for transnational terrorist groups due to state weakness, Islamic State has had difficulty making headway in the country. In this article, the authors argue that Islamic State’s failures in Pakistan are due to competition from other groups. Drawing on the terrorist competition literature and interviews with Pakistani counterterrorism officials, the authors find that the presence of other groups in Pakistan meant there was little demand for what Islamic State offered. Islamic State relied on splinter groups and defectors for recruitment, which alienated mainstream groups and harmed the group’s capacity. Islamic State’s competition problems were exacerbated by its internationalist ideology, which was at odds with that of many groups in Pakistan, and allowed opposing groups to present themselves as reasonable alternatives to other actors. Despite Islamic State’s lack of success, it and its allies have still engaged in extreme violence in Pakistan as a result of attempts to outbid other groups. This article has implications for fighting terrorism in Pakistan and more generally.     

李续宾败亡三河之役的主要原因新议——与洪均先生商榷

李续宾败亡三河之役的深层原因，不在于“抢掠与放纵”而“严重地削弱了湘军战斗力”，而主要体现在这四个方面：一是天京事变后太平天国新的领导核心的确立，太平军战斗力由此增强；二是李续宾湘军战线拉得过长，兵力分散，很难发挥集中优势兵力敢打敢拼、攻坚克强的特长；三是湖广总督官文配合不力，赵克彰等部湘军临阵脱逃，致使李续宾部湘军陷入孤军作战的绝境；四是李续宾求胜心切，意气用事，听不进他人建议，未能及时采取战略转移的措施。     

MOMENT RESISTING WELDED CONNECTIONS: AN EXTENSIVE REVIEW OF DESIGN PRACTICE AND EXPERIMENTAL RESEARCH IN USA,JAPAN AND EUROPE

Welded connections, widely used in seismic moment resisting frames (MRFs) in USA, Japan and Europe, have been extensively investigated during the 1990s in order to improve their performance under severe earthquakes. In order to correctly evaluate the results of experimental research on welded connections, the differences among the American, Japanese and European current practices in designing the frame structural systems and in detailing the beam-to-column connections should be firstly appraised. In this paper, the major aspects characterising the USA, Japan and Europe design practice in moment resisting welded connections are reported, the differences are underlined and the main issues recently addressed in experimental research are reviewed. Among the several parameters which affect the connection performance, attention is focused on the effect of the beam cross-section size. Thus conclusions are drawn in terms of plastic rotation capacity as dependant on the beam size.     

A SUMMARY OF RESULTS OF SIMULATED SEISMIC LOAD TESTS ON REINFORCED CONCRETE BEAM-COLUMN JOINTS,BEAMS AND COLUMNS WITH SUBSTANDARD REINFORCING DETAILS

The results of some simulated seismic load tests on reinforced concrete one-way interior and exterior beam-column joints with substandard reinforcing details typical of buildings constructed in New Zealand before the 1970s are described. The tests were conducted using both deformed and plain round longitudinal reinforcement. The interior beam-column joint cores lacked transverse reinforcement and the longitudinal bars passing through the joint core were poorly anchored. The exterior beam-column joint units contained very little transverse reinforcement in the members and in the joint core. In one exterior beam-column joint unit the beam bar hooks were not bent into the joint core. That is, the hooks at the ends of the top bars were bent up and the hooks at the ends of the bottom bars were bent down. This anchorage detail was common in many older buildings constructed before the 1970s. In the other exterior beam-column joint unit the hooks at the ends of the bars were bent into the joint core as in current practice. The improvement in performance of the joint with beam bars anchored according to current practice is demonstrated. In addition, tests were conducted on interior joints with lap splices in the beam longitudinal reinforcement bars near the column face. The tests were conducted using both deformed and plain round longitudinal reinforcement. Tests were also conducted on columns with plain round bar longitudinal reinforcement and inadequate transverse reinforcement.

The reinforcing details were close to identical to those in an existing seven storey reinforced concrete building that was designed and built in New Zealand in the late 1950s.

The test results give an indication of the performance of beam-column joints and members with the above now out-of-date reinforcing details.

The test results reported are a summary of results reported in a number of publications written since 1994.     

DUCTILITY AND LOAD CARRYING CAPACITY PREDICTION OF STEEL BEAM-TO-COLUMN CONNECTIONS UNDER CYCLIC REVERSAL LOADING

Abstract

The economy and reliability of steel-framed buildings in seismic areas depend basically on the hysteretic behaviour of its individual components, such as members and joints. With reference to the latter, despite the recent semi-continuous frame approach (which appears generally very convenient for the design of low- and medium-rise steel buildings), the present state of knowledge does not allow for a complete understanding of the behaviour and the low-cycle fatigue life of beam-to-column connections under dynamic loads.

This paper presents a criterion for the definition of the low-cycle fatigue strength of steel connections, and proposes two approaches for the design of steel frames in seismic zones via the assessment of the fatigue damage, which is evaluated alternatively on the basis of either the ductility or of the load carrying capacity.