2,298 research outputs found
Centrifuge modeling of rocking-isolated inelastic RC bridge piers
Experimental proof is provided of an unconventional seismic design concept, which is based on deliberately underdesigning shallow foundations to promote intense rocking oscillations and thereby to dramatically improve the seismic resilience of structures. Termed rocking isolation, this new seismic design philosophy is investigated through a series of dynamic centrifuge experiments on properly scaled models of a modern reinforced concrete (RC) bridge pier. The experimental method reproduces the nonlinear and inelastic response of both the soil-footing interface and the structure. To this end, a novel scale model RC (1:50 scale) that simulates reasonably well the elastic response and the failure of prototype RC elements is utilized, along with realistic representation of the soil behavior in a geotechnical centrifuge. A variety of seismic ground motions are considered as excitations. They result in consistent demonstrably beneficial performance of the rocking-isolated pier in comparison with the one designed conventionally. Seismic demand is reduced in terms of both inertial load and deck drift. Furthermore, foundation uplifting has a self-centering potential, whereas soil yielding is shown to provide a particularly effective energy dissipation mechanism, exhibiting significant resistance to cumulative damage. Thanks to such mechanisms, the rocking pier survived, with no signs of structural distress, a deleterious sequence of seismic motions that caused collapse of the conventionally designed pier. © 2014 The Authors Earthquake Engineering & Structural Dynamics Published by John Wiley & Sons Ltd
Recommended from our members
Regional initiatives and the UN 2001 Conference: Building Mutual Support and Complementarity.
yesAs the agenda for the United Nations (UN) 2001 Conference on The Illicit Trade in Small Arms and Light Weapons in All Its Aspects takes shape, governments should begin to identify a set
of standards, mechanisms and specific agreements that will help consolidate, reinforce and
co-ordinate regional and national measures to address the problem of the proliferation and
misuse of small arms. An important element of this approach will be to build upon the wealth
of regional and national experiences and perspectives that illustrate the different contexts
in which efforts to combat the proliferation and misuse of small arms and light weapons have
occurred. At the same time, agreements reached at the UN 2001 Conference should be
substantial, establishing an agreed comprehensive `international action programmeÂż f o r
sustained global effort on this complex problem. However there remain issues and concerns
that are common to all regions: these should be identified and addressed internationally
within the context of the UN 2001 Conference.
This briefing, the second in the Biting the Bullet series, reviews some of the current regional
e fforts on small arms and light weapons. It identifies common approaches that have been used
in different regions to counter the proliferation and misuse of small arms and light weapons,
these include: law enforcement and crime control; supplier restraint and transparency; national
legislation and regulation of arms; and arms reduction and control. The briefing analyses
initiatives using these approaches that are moving forward in West Africa, Eastern and
Southern Africa, the European Union (EU), and the development of cooperation between
EU Member States and other countries and regional organizations, including Cambodia
and the Southern African Development Community. The briefing identifies the impact and
priorities of these initiatives, suggesting ways in which the UN 2001 Conference is both
relevant to the region and what the region can contribute to the outcomes of the Conference.
The briefing concludes with recommendations on the ways in which regional processes can be
reinforced and further developed by the international community, focusing especially on the
contribution of the UN 2001 Conference. Experience is showing that much of what happens
nationally and regionally needs reinforcement and further development with assistance from
the international community. The UN 2001 Conference comes at an important time for providing
the framework Âż through the international action programme Âż to develop, reinforce and
c o-ordinate these national and regional processes, through developing appropriate international
norms, standards, programmes and mechanisms. Using the illustration of combating illicit arms
trafficking, this briefing outlines some of the processes that could be taken forward through
the UN 2001 Conference which would build upon and strengthen national and regional eff o r t s .
The briefing contains an annex, which provides background information on many current
regional and international initiatives, including those in Africa, the Americas, Asia, Europe
and inter-regionally, such as the Organisation for Security and Co-operation in Europe and
the North Atlantic Treaty Organisation
Recommended from our members
Implementing the UN Action Programme for Combating the Illicit Trafficking in Small Arms and Light Weapons in All Its Aspects.
yesHistorically, UN conferences have been criticised for resulting more in compromises than in
commitments to real change, which is also a charge that has been levelled against the UN
Conference on the Illicit Trade in Small Arms and Light Weapons in All Its Aspects (UN Small
Arms Conference). The consensus-based approach adopted throughout the negotiations had
the advantage of binding all participating States to all aspects of the agreed Programme of
Action (PoA), but it also ensured that it would be difficult to achieve a sufficiently rigorous and
comprehensive agreement on all of the measures required to tackle the trafficking,
proliferation and misuse of small arms and light weapons (SALW). Therefore, in spite of the
efforts of many governments and NGOs, the UN Small Arms Conference did not agree
sufficiently robust agreements in several areas. Nonetheless, it was a valuable and productive
process. The resulting PoA includes a reasonably comprehensive set of key principles and
commitments, which provide a basis for taking forward action at national, regional and global
levels. The PoAwas agreed by all of the participating States, amounting to more than 100,
and each are politically bound to adopt and implement it.
Given that the UN Small Arms Conference was the first of its kind, its achievement in
generating political will and momentum for efforts to control SALW is important. Although
many of the commitments are weaker and less comprehensive than hoped for by many
governments and organisations, it is significant that the PoAcontains at least some important
commitments in all but two of the `coreÂż issue areas raised by States. The two exceptions
relate to transfers to non-State actors and to civilian trade, possession and use of SALW,
restrictions which were strongly opposed by the USA. Equally, human rights related issues
were noteworthy by their absence in the PoA.
Whilst the process of reaching agreement began with a far-reaching draft PoA in December
2000 (A/Conf.192/L.4), most of the comments that were tabled on this text during the second
Preparatory Committee in January 2001 came from countries that sought to weaken its
commitments. The subsequent draft (A/Conf.192/L.4/Rev.1) was therefore weaker, with the
result that progressive States faced an uphill task in seeking to strengthen its provisions.
The next draft PoA emerged at the UN Small Arms Conference itself in the form of a third draft
(A/Conf.192/L.5). Although still limited in a number of key areas Âż such as export criteria and
transparency Âż this document went further than L.4/Rev.1 in a number of respects and included
specific international commitments, including on brokering and tracing lines of supply. This,
however, proved too ambitious an agenda for a small group of States and in the end the document
that was adopted by consensus (A/Conf.192/L.5/Rev.1) represented a lower-level compromise.
Despite the difficulties of agreeing the consensus-based PoA, the process culminating in the
agreement was perhaps as important as the agreement itself. UN Small Arms Conference
represented the first time that all UN Member States had met to discuss the illicit trade in SALW
in all its aspects with a view to agreeing a comprehensive set of measures to address the
problem. Although many of the commitments contained in the PoAare couched in equivocal
language that will allow States to do as much or as little as they like, it is clear that the UN Small
Arms Conference has contributed to a much better understanding, amongst all stakeholders, of
the nature of the illicit trade in SALW and of the particular concerns and priorities of different
countries and sub-regions. It is also clear that although the Programme of Action provides a set
of minimum standards and commitments which all states should adopt, it also encourages
further action from all States willing to adopt more stringent commitments and stronger
programmes. There is a willingness among a number of States to build upon the PoAand take
more concrete and far-reaching measures at national, sub-regional, regional and international
levels, such as specific arrangements for tracing co-operation, or mechanisms to co-ordinate
e fforts to improve stockpile security or weapons destruction. This briefing provides a critical assessment of key provisions in the UN Small Arms
Conference PoA. Section 1 measures the overall outcomes of the conference against those
that the Biting the Bullet (BtB) project proposed as optimal conclusions, and suggests ways to
put the commitments contained in the PoA into practice. Section 2 assesses the
implementation and follow-up commitments contained in the PoA, and identifies ways of
promoting the implementation of Sections III and IV, as well as options for making the most of
the Biennial Meetings of States and the Review Conference in 2006. Section 3 examines
funding and resourcing possibilities for the PoA including identifying needs, mobilising
resources and matching needs with resources. The final section of the briefing focuses on the
way forward, and in particular on how implementation of the PoA could build on existing
regional initiatives and develop common international approaches to controlling SALW
proliferation, availability and misuse. It also examines how action to prevent and combat the
illicit trade in SALW in all its aspects can be taken forward at sub-regional and regional levels
in conjunction with all major stakeholders, including civil society, in the period leading up to
the first Review Conference
Spectrophotometric Studies of Dilute Aqueous Periodate Solutions
The solubility behavior of various sparingly soluble periodates was found to be anomalous as interpreted through the equilibrium constants for the dilute aqueous periodate system as reported in the literature. Thus it was necessary to investigate these equilibria as a possible reason for the anomaly. Reinterpretation of this solubility behavior in light of the results of this investigation will be reported at a later date
Teleological Essentialism
Placeholder essentialism is the view that there is a causal essence that holds category members together, though we may not know what the essence is. Sometimes the placeholder can be filled in by scientific essences, such as when we acquire scientific knowledge that the atomic weight of gold is 79. We challenge the view that placeholders are elaborated by scientific essences. On our view, if placeholders are elaborated, they are elaborated Aristotelian essences, a telos. Utilizing the same kinds of experiments used by traditional essentialistsâinvolving superficial change (study 1), transformation of insides (study 2), acquired traits (study 3) and inferences about offspring (study 4)âwe find support for the view that essences are elaborated by a telos. And we find evidence (study 5) that teleological essences may generate category judgments
- âŠ