A strategy of quick hierarchization of road bridge maintenance activities

The control and maintenance of infrastructures is a crucial aspect for the sustainability and development of the economic and social activities of a country. The managing authorities, in order to preserve the efficiency and safety of the traffic flows, have to deal with a rather old infrastructure asset that is often in a non-optimal conservation state with an increasing degradation process induced by the increment of the traffic loads and by the environmental actions. The situation is exacerbated by the limited economic resources and reduced workforces at disposal with the consequence that an order of priority in the maintenance plain is anavoidable. This work provides a logical tool to define the hierarchy of the maintenance plain of the infrastructural heritage based on one hand on the structure state of conservation and on the other hand on the context in which the construction is integrated

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On the Tradeoff between Performance and Programmability for Software Defined WiFi Networks

Wireless Communications and Mobile Computing ◽

10.1155/2018/1083575 ◽

2018 ◽

Vol 2018 ◽

pp. 1-12 ◽

Cited By ~ 8

Author(s):

Tausif Zahid ◽

Xiaojun Hei ◽

Wenqing Cheng ◽

Adeel Ahmad ◽

Pasha Maruf

Keyword(s):

Performance Optimization ◽

Traffic Flows ◽

Network Access ◽

Performance Measurements ◽

Throughput Performance ◽

Wifi Networks ◽

Traffic Loads ◽

High Bandwidth ◽

Potential Benefits ◽

Sdn Controller

WiFi has become one of the major network access networks due to its simple technical implementation and high-bandwidth provisioning. In this paper, we studied software defined WiFi networks (SDWN) against traditional WiFi networks to understand the potential benefits, such as the ability of SDWN to effectively hide the handover delay between access points (AP) of the adoption of the SDWN architecture on WiFi networks and identify representative application scenarios where such SDWN approach could bring additional benefits. This study delineated the performance bottlenecks such as the throughput degradation by around 50% compared with the conventional WiFi networks. In addition, our study also shed some insights into performance optimization issues. All of the performance measurements were conducted on a network testbed consisting of a single basic service set (BSS) and an extended service set (ESS) managed by a single SDN controller deployed with various laboratory settings. Our evaluation included the throughput performance under different traffic loads with different number of nodes and packet sizes for both TCP and UDP traffic flows. Handover delays were measured during the roaming phase between different APs against the traditional WiFi networks. Our results have demonstrated the tradeoff between performance and programmability of software defined APs.

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Operation and maintenance of Osmangazi Bridge

IABSE Symposium, Guimarães 2019: Towards a Resilient Built Environment Risk and Asset Management ◽

10.2749/guimaraes.2019.1181 ◽

2019 ◽

Author(s):

Fatih Zeybek

Keyword(s):

Suspension Bridge ◽

Maintenance Strategy ◽

Operation And Maintenance ◽

Bridge Maintenance ◽

The World ◽

Inspection And Maintenance ◽

Maintenance Activities

Osmangazi Bridge is a suspension bridge with a 1550 meter main span is the fourth longest span bridge in the world.The routine maintenance of the bridge are done by the Operator GIIB and the heavy repairs by the Concessionaire (Otoyol A.Ş.) based on the recommendations of the Bridge EPC contractor.This paper summarizes the basics of the Osmangazi Bridge’s operation maintenance activities, which emphasizes to the Bridge maintenance strategy and the instructions to be applied for the operation and maintenance staff and subcontractors in order for them to undertake inspection and maintenance of the bridge. A summary of overall inspection and maintenance programs outlining the required anticipated tasks over the time is also given in the paper.

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Impact of Environmental Exposure Conditions on the Maintenance of Facades’ Claddings

Buildings ◽

10.3390/buildings11040138 ◽

2021 ◽

Vol 11 (4) ◽

pp. 138

Author(s):

Cláudia Ferreira ◽

Joana Barrelas ◽

Ana Silva ◽

Jorge de Brito ◽

Ilídio S. Dias ◽

...

Keyword(s):

Environmental Exposure ◽

Degradation Process ◽

Building Envelope ◽

Decision Makers ◽

Exposure Condition ◽

Environmental Actions ◽

Tiling Systems ◽

Building Components ◽

Maintenance Requirements ◽

Over Time

Façades, as the most external building envelope component, are subject to different ex-ternal environmental loads, such as: Temperature, precipitation, damp, and wind. Therefore, the contribution of environmental actions to the occurrence of defects in façades claddings is an important subject of study since these actions strongly affect the degradation process and natural ageing of these components during their service life. In this study, a methodology to support decision-makers in the process of selecting a façade cladding system and the maintenance strategy to implement is presented and discussed. This methodology covers the performance of four façade claddings (ceramic tiling systems (CTS), natural stone claddings (NSC), external thermal insulation composite systems (ETICS), and architectural concrete façades (ACF)) over time, according to three environmental exposure variables (exposure to damp, distance from the sea, and orientation). The databases were established based on the diagnosis of the degradation condition of these claddings in-service conditions, in Portugal. The results reveal that the environmental exposure variables have a significant impact on maintenance requirements and costs. For all the categories of the environmental exposure condition variables, under all scenarios, ETICS is the least favorable constructive solution while CTS is the most advantageous solution. Furthermore, the results show that properly implemented maintenance activities enhance the performance level of building components, which positively affects their degradation behavior over time.

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Monitoring of the Great Belt Bridge hanger vibrations and expansion joint movements using Digital Image Correlation

IABSE Conference, Copenhagen 2018: Engineering the Past, to Meet the Needs of the Future ◽

10.2749/copenhagen.2018.409 ◽

2018 ◽

Author(s):

Jan Winkler ◽

Chris Hendy

Keyword(s):

Digital Image Correlation ◽

Digital Image ◽

Suspension Bridge ◽

Image Correlation ◽

Civil Infrastructure ◽

Expansion Joint ◽

Bridge Maintenance ◽

Infrastructure System ◽

Maintenance Activities ◽

Great Belt

Civil infrastructure system owners are often faced with an increasingly impossible set of management challenges. Informed decisions on timely intervention for effective bridge maintenance activities rely on good quality, accurate and reliable asset condition data. Digital image correlation (DIC) is a noncontact photogrammetry technique that can be used for monitoring by imaging a bridge component periodically and computing strain and deformation from images without traffic disruption. This paper describes the use of DIC for the monitoring of the Great Belt Bridge wind‐induced hanger vibrations and temperature‐induced movements of the expansion joint. Both DIC measurements provided previously unavailable data and informed next steps with respect to the maintenance strategy. To the authors knowledge these are one of the first such vision‐based structural health monitoring campaigns carried out on a suspension bridge.

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Techniques For The Preparation of Tissue Samples Containing Injectable Polymer Microcapsules

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100120242 ◽

1985 ◽

Vol 43 ◽

pp. 710-711

Author(s):

G.E. Visscher ◽

R. L. Robison ◽

G. J. Argentieri

Keyword(s):

Drug Delivery ◽

Drug Delivery Systems ◽

Gastrocnemius Muscle ◽

Degradation Process ◽

Delivery Systems ◽

Tissue Reaction ◽

Electron Microscopic ◽

Tissue Samples ◽

Injectable Polymer ◽

Microscopic Techniques

The use of various bioerodable polymers as drug delivery systems has gained considerable interest in recent years. Among some of the shapes used as delivery systems are films, rods and microcapsules. The work presented here will deal with the techniques we have utilized for the analysis of the tissue reaction to and actual biodegradation of injectable microcapsules. This work has utilized light microscopic (LM), transmission (TEM) and scanning (SEM) electron microscopic techniques. The design of our studies has utilized methodology that would; 1. best characterize the actual degradation process without artifacts introduced by fixation procedures and 2. allow for reproducible results.In our studies, the gastrocnemius muscle of the rat was chosen as the injection site. Prior to the injection of microcapsules the skin above the sites was shaved and tattooed for later recognition and recovery. 1.0 cc syringes were loaded with the desired quantity of microcapsules and the vehicle (0.5% hydroxypropylmethycellulose) drawn up. The syringes were agitated to suspend the microcapsules in the injection vehicle.

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