Retrofit of Aerodynamic Cable Instability on a Cable-Stayed Bridge: Case Study

Author(s):  
Niket M. Telang ◽  
Charles M. Minervino ◽  
Paul G. Norton

Elegantly poised over the Mobile River, the twin pylons and the semi-harped cable stays of the Cochrane Bridge subtly complement the vast and undulating landscape of the Mobile Bay as the bridge carries US Route 90 over the Mobile River in Alabama. In February 1998, light rain drizzled on the bridge, and a weather station nearby recorded wind speeds of about 48 km/h (30 mph). Under these seemingly mild weather conditions, the normally immobile cable stays started to vibrate, and within moments, these nascent vibrations reached amplitudes of more than 1.2 m (4 ft). Alarmed by this event, the Alabama Department of Transportation (ALDOT) took immediate action to ensure the continued safety and serviceability of the bridge. A team of consultants was selected by ALDOT to investigate mitigation measures for the large-amplitude cable-stay vibrations. The fast-tracked comprehensive program planned and implemented to inspect, test, document, and evaluate the effects of the large-amplitude vibrations and the recommendation of retrofit measures that would limit future occurrences of such cable-stay vibrations on the Cochrane Bridge are described in detail.

1998 ◽  
Vol 37 (1) ◽  
pp. 155-162
Author(s):  
Flemming Schlütter ◽  
Kjeld Schaarup-Jensen

Increased knowledge of the processes which govern the transport of solids in sewers is necessary in order to develop more reliable and applicable sediment transport models for sewer systems. Proper validation of these are essential. For that purpose thorough field measurements are imperative. This paper renders initial results obtained in an ongoing case study of a Danish combined sewer system in Frejlev, a small town southwest of Aalborg, Denmark. Field data are presented concerning estimation of the sediment transport during dry weather. Finally, considerations on how to approach numerical modelling is made based on numerical simulations using MOUSE TRAP (DHI 1993).


Impact ◽  
2020 ◽  
Vol 2020 (3) ◽  
pp. 26-28
Author(s):  
Tsukasa Ohba

Volcanology is an extremely important scientific discipline. Shedding light on how and why volcanoes erupt, how eruptions can be predicted and their impact on humans and the environment is crucial to public safety, economies and businesses. Understanding volcanoes means eruptions can be anticipated and at-risk communities can be forewarned, enabling them to implement mitigation measures. Professor Tsukasa Ohba is a scientist based at the Graduate School of International Resource Studies, Akita University, Japan, and specialises in volcanology and petrology. Ohba and his team are focusing on volcanic phenomena including: phreatic eruptions (a steam-driven eruption driven by the heat from magma interacting with water); lahar (volcanic mudflow); and monogenetic basalt eruptions (which consist of a group of small monogenetic volcanoes, each of which erupts only once). The researchers are working to understand the mechanisms of these phenomena using Petrology. Petrology is one of the traditional methods in volcanology but has not been applied to disastrous eruptions before. The teams research will contribute to volcanic hazard mitigation.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
K. Pugh ◽  
M. M. Stack

AbstractErosion rates of wind turbine blades are not constant, and they depend on many external factors including meteorological differences relating to global weather patterns. In order to track the degradation of the turbine blades, it is important to analyse the distribution and change in weather conditions across the country. This case study addresses rainfall in Western Europe using the UK and Ireland data to create a relationship between the erosion rate of wind turbine blades and rainfall for both countries. In order to match the appropriate erosion data to the meteorological data, 2 months of the annual rainfall were chosen, and the differences were analysed. The month of highest rain, January and month of least rain, May were selected for the study. The two variables were then combined with other data including hailstorm events and locations of wind turbine farms to create a general overview of erosion with relation to wind turbine blades.


Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1884
Author(s):  
Ana Juárez ◽  
Knut Alfredsen ◽  
Morten Stickler ◽  
Ana Adeva-Bustos ◽  
Rodrigo Suárez ◽  
...  

Floods are among the most damaging of natural disasters, and flood events are expected to increase in magnitude and frequency with the effects of climate change and changes in land use. As a consequence, much focus has been placed on the engineering of structural flood mitigation measures in rivers. Traditional flood protection measures, such as levees and dredging of the river channel, threaten floodplains and river ecosystems, but during the last decade, sustainable reconciliation of freshwater ecosystems has increased. However, we still find many areas where these traditional measures are proposed, and it is challenging to find tools for evaluation of different measures and quantification of the possible impacts. In this paper, we focus on the river Lærdal in Norway to (i) present the dilemma between traditional flood measures and maintaining river ecosystems and (ii) quantify the efficiency and impact of different solutions based on 2D hydraulic models, remote sensing data, economics, and landscape metrics. Our results show that flood measures may be in serious conflict with environmental protection and legislation to preserve biodiversity and key nature types.


Fire ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 11
Author(s):  
Charlotte Fafet ◽  
Erinë Mulolli Zajmi

Fires are among the most frequently recurring hazards affecting museums and cultural heritage sites. The fires of the National Museum of Brazil in 2018 and of Notre Dame de Paris in 2019 showed that the consequences of such events can be heavy and lead to irreversible heritage losses. In Kosovo, few studies were made about the risks that can affect cultural heritage sites. A project led by the NGO Kosovo Foundation for Cultural Heritage without Borders (CHwB Kosova) in 2018 explored the most prevalent risks for the cultural heritage sites of the country and highlighted fire as a predominant risk in Kosovo. In order to better understand it, vulnerability assessments were conducted in several museums in Kosovo. Data were collected through field visits in the different museums, in which interviews with staff members as well as observations were conducted. The aim of this paper is to present the main results of the fire vulnerability assessments conducted in Kosovo’s museums in 2018. An important aspect of this project is the approach to collect information in data-scarce environments. It is believed that the questionnaires used to lead interviews with museums’ staff members could help other practitioners to collect data in such contexts and evaluate more easily the risk of fire for the museums and their collections. In the context of Kosovo, one of the main findings is the identification and prioritisation of measures to ensure better protection of Kosovar museums. Structural mitigation measures such as alarm and fire suppression systems are not the only elements necessary to improve the resilience of Kosovar museums to fire. Indeed, the promotion of risk awareness, the training of staff members and the realisation of crisis simulation exercises are just as important in order to prevent and detect a fire, and above all, to respond quickly and accurately if a fire occurs.


2021 ◽  
Vol 11 (5) ◽  
pp. 2153
Author(s):  
Nadia Giuffrida ◽  
Maja Stojaković ◽  
Elen Twrdy ◽  
Matteo Ignaccolo

Container terminals are the main hubs of the global supply chain but, conversely, they play an important role in energy consumption, environmental pollution and even climate change due to carbon emissions. Assessing the environmental impact of this type of port terminal and choosing appropriate mitigation measures is essential to pursue the goals related to a clean environment and ensuring a good quality of life of the inhabitants of port cities. In this paper the authors present a Terminal Decision Support Tool (TDST) for the development of a container terminal that considers both operation efficiency and environmental impacts. The TDST provides environmental impact mitigation measures based on different levels of evolution of the port’s container traffic. An application of the TDST is conducted on the Port of Augusta (Italy), a port that is planning infrastructural interventions in coming years in order to gain a new role as a reference point for container traffic in the Mediterranean.


2021 ◽  
Vol 130 ◽  
pp. 103668
Author(s):  
Hamid Reza Moghaddasi ◽  
Mojtaba Azhari ◽  
Mohammad Mehdi Saadatpour ◽  
Saeid Sarrami-Foroushani

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