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

Climate change effects on buckling strength of steel plate elements.

This research is aim at investigating Climate Change effects on buckling strength of steel plate elements. Climate change is the consequence of global warming as a result of the increase of greenhouse gases in the atmosphere due to both natural and anthropogenic reasons. This can lead to changes in environmental and atmospheric pollution parameters which may affect the deterioration rate of engineering materials and infrastructural systems. A review of the state-of-the art dose-response function, which are capable of linking atmospheric pollutants concentrations and environmental variables with long-term deterioration, was carried out to quantify the potential impact of climate change on material corrosion loss of carbon steel. The corrosion loss was then linked with the long-term buckling strength of steel plate elements to produce long-term performance models. A full mapping of corrosion loss from 0%-90% section thickness loss under compressive and shear loads was undertaken using both linear and non-linear buckling finite element analyses through ABAQUS in order to find out the impact of the effect of section thickness loss on the buckling strength of steel plate elements used in plate girder bridges. A total of 522 three-dimensional finite elements models of realistic plate elements were analysed under different corrosion intensities and patterns, the latter including uniform and non-uniform corrosion as well as pitting corrosion. The dose-response functions were then utilised to predict long-term corrosion under different climate scenarios. The damage assessment by the well-known ISO model was compared to that of two other models, Klinesmith et al. (2007) and Kallias et al. (2016). From the damage assessment using the dose-response functions it was discovered that the ISO model tends to underestimate the corrosion loss while the Klinesmith and Kallias models were found to result in comparable predictions for corrosion loss over time. The buckling FE results were normalised and plotted in terms of reduction factor curves which can offer a quick way for estimating the buckling strength loss over time, for different corrosion scenarios. These curves can offer useful support to infrastructure owners and managers to assess the implications of corrosion on plate elements and plan effective maintenance strategies throughout the life cycle of assets in the face of challenging climate change uncertainties and financial constraints

Climate change effects on buckling strength of steel plate elements.

This research is aim at investigating Climate Change effects on buckling strength of steel plate elements. Climate change is the consequence of global warming as a result of the increase of greenhouse gases in the atmosphere due to both natural and anthropogenic reasons. This can lead to changes in environmental and atmospheric pollution parameters which may affect the deterioration rate of engineering materials and infrastructural systems. A review of the state-of-the art dose-response function, which are capable of linking atmospheric pollutants concentrations and environmental variables with long-term deterioration, was carried out to quantify the potential impact of climate change on material corrosion loss of carbon steel. The corrosion loss was then linked with the long-term buckling strength of steel plate elements to produce long-term performance models. A full mapping of corrosion loss from 0%-90% section thickness loss under compressive and shear loads was undertaken using both linear and non-linear buckling finite element analyses through ABAQUS in order to find out the impact of the effect of section thickness loss on the buckling strength of steel plate elements used in plate girder bridges. A total of 522 three-dimensional finite elements models of realistic plate elements were analysed under different corrosion intensities and patterns, the latter including uniform and non-uniform corrosion as well as pitting corrosion. The dose-response functions were then utilised to predict long-term corrosion under different climate scenarios. The damage assessment by the well-known ISO model was compared to that of two other models, Klinesmith et al. (2007) and Kallias et al. (2016). From the damage assessment using the dose-response functions it was discovered that the ISO model tends to underestimate the corrosion loss while the Klinesmith and Kallias models were found to result in comparable predictions for corrosion loss over time. The buckling FE results were normalised and plotted in terms of reduction factor curves which can offer a quick way for estimating the buckling strength loss over time, for different corrosion scenarios. These curves can offer useful support to infrastructure owners and managers to assess the implications of corrosion on plate elements and plan effective maintenance strategies throughout the life cycle of assets in the face of challenging climate change uncertainties and financial constraints