Long-term deterioration effects on the buckling strength of metallic bridge girders

Bridges are an essential part of the transport infrastructure. A considerable number of these bridges are metallic, in many cases exceeding 100 years of age having suffered deterioration from environmental attack such as atmospheric corrosion. In order for infrastructural managers to make informed decision in terms of life-cycle cost perspective, reliable prediction of the remaining strength and service life of deteriorating bridges is essential. Deterioration models have been developed over the years to predict long-term material loss under different atmospheric conditions and environments. The aim of this paper is to quantify the effects of long-term deterioration, based on these models, on the remaining strength of metallic bridge girders, comprising of a number of plates. To obtain a useful insight into this problem, the finite element method is employed. In this paper, different plate elements, of varying slenderness and boundary conditions and representative of real bridge configurations, are analysed under different deterioration scenarios, brought about through material loss at different locations of the element. The effects of various parameters such as the degree/severity of material loss and the corrosion pattern (uniform versus non-uniform) on the buckling strength of the plates are quantified through both linear eigenvalue and non-linear analyses. The results of this study show that critical buckling strength of web panels may significantly drop at higher percentages of corrosion degradation and patterns, with the failure mode likely to change with increased deterioration. Differences between the critical buckling stresses obtained from the linear and non-linear analyses are presented

Performance of lightweight granulated glass concrete beams reinforced with basalt FRP bars

This paper presents an investigation into the flexural behaviour of basalt FRP reinforced concrete beams through experimental and analytical methods. To achieve the research objectives, four concrete beams reinforced with steel and four identical concrete beams reinforced with BFRP bars were tested under four-point bending. The main parameters examined under the tests are the type of concrete (lightweight foam glass concrete and normal concrete) and the type of longitudinal reinforcement bars (BFRP and steel). Test results are presented in terms of failure modes; deformation crack pattern and the ultimate moment of resistance are presented. The experimental results are analysed and compared to predictive models proposed by ACI 440.1R, 2006 and BS EN 1992, Eurocode 2, for deformations and ultimate flexural capacities of the steel and BFRP reinforced concrete beams. The experimental results indicated that the flexural capacity decreased for the beams reinforced with BFRP bars compared to that of a corresponding beam reinforced with steel bars. Both types of beams failed in the modes predicted. The prediction models underestimated the flexural capacity of BFRP reinforced concrete beams. The increase in foam glass aggregate content was observed to reduce the cracking load by almost 10-40% and 25-50% for steel and BFRP reinforced concrete beams, respectively. The flexural capacities of BFRP reinforced beams were underestimated by using equations stipulated in ACI 440.1R and Eurocode 2 codes of practice. © 2019 Growing Science Ltd. All rights reserved

Competing ideologies of Russia's civil society

Many analysts and public opinion makers in the West conflate the notions of Russia’s non-systemic liberal opposition and the country’s civil society. Indeed, despite garnering the support of a minority of Russia’s population, non-systemic liberal opposition represents a well-organized civic group with a clearly articulated agenda and the ability to take action. Yet, does Russia’s civil society end there? A closer look at the country’s politics shows that Russia has a substantial conservative-traditionalist faction that has also developed agenda for action and formulated opinions. This group is anti-liberal rather than illiberal ideologically and pro-strong state/pro a geopolitically independent Russia rather than pro-Kremlin politically. The interaction between liberal and conservative civic groups represents the battle of meanings, ideas, and ethics, and ultimately determines the future trajectory of Russia’s evolution. Thus, the analysis of Russia’s civil society must represent a rather more nuanced picture than a mere study of the liberal non-systemic opposition. This article will examine the complexity of Russia’s civil society scene with reference to the interplay between the liberal opposition and conservative majority factions. The paper will argue that such complexity stems from ideological value pluralism that falls far beyond the boundaries of the liberal consensus, often skewing our understanding of political practice in Russia