scholarly journals Scenarios for Life Cycle Studies of Bridge Concrete Structure Maintenance

2020 ◽  
Vol 12 (22) ◽  
pp. 9557
Author(s):  
Hyunsik Kim ◽  
Sungho Tae ◽  
Yonghan Ahn ◽  
Jihwan Yang

The sustainability of structures during their construction and service life has become a widespread topic of interest. To ensure the sustainability of bridges, maintenance databases can be analyzed to determine the status changes and required maintenance of existing bridges. The results of this analysis can then be used to predict the environmental impacts and costs incurred during ongoing maintenance of new bridges to prepare accordingly for the future. To prepare for future events, this study utilizes the US National Bridge Inventory to analyze changes in the condition rating of bridge decks and substructures according to their service years, and suggests maintenance scenarios for the service life of bridge deck and substructure concrete by investigating the maintenance activities according to service years. The factors for applying the scenarios in Korea and conceptual equations for life cycle studies which apply the scenarios are discussed for further study in the life cycle assessment field of bridges.

Author(s):  
Joydeep Das ◽  
Arjun Sil

The reinforced concrete (RC) bridges deteriorate essentially due to strength loss induced by aging of the structure, extreme weathering conditions, and unplanned increased service loads. However, these load variations and aging factors equally could compromise structural reliability, and service life for continuous satisfactory operation of service bridges for future performance. A reasonable model of bridge strength and applied loads becomes the basis of accurate prediction of bridge functionality. Hence, time-dependent reliability approaches could be used efficiently to gain a reliable understanding of issues facing by the bridges in the study area for appropriate solutions. In this paper, the reliability of bridges under harsh conditions studied using time-variant and time-invariant reliability models in which both load and resistance considered as a time-dependent parameter. A combination of condition rating (CR) and time-dependent load employed to attain accurate insights about the degradation of structural resistance of the existing bridges. The result shows the significant impact of aging as well as traffic loads influence in the service life of both national highways (NH) and rural road service bridges. These observations might be used to adopt appropriate planning strategies as well as rational decisions to ensure the safety of the bridges for future operation.


2019 ◽  
Vol 9 (1) ◽  
pp. 63-75
Author(s):  
Azam Nabizadeh ◽  
Habib Tabatabai ◽  
Mohammad A. Tabatabai

AbstractBridge decks are a significant factor in the deterioration of bridges, and substantially affect long-term bridge maintenance decisions. In this study, conditional survival (reliability) analysis techniques are applied to bridge decks to evaluate the age at the end of service life using the National Bridge Inventory records. As bridge decks age, the probability of survival and the expected service life would change. The additional knowledge gained from the fact that a bridge deck has already survived a specific number of years alters (increases) the original probability of survival at subsequent years based on the conditional probability theory. The conditional expected service life of a bridge deck can be estimated using the original and conditional survival functions. The effects of average daily traffic and deck surface area are considered in the survival calculations. Using Wisconsin data, relationships are provided to calculate the probability of survival of bridge decks as well as expected service life at various ages. The concept of survival dividend is presented and the age when rapid deterioration begins is defined.


Author(s):  
Tadashi Kanno ◽  
Yasushi Kamihigashi ◽  
Hiromu Ishida

Rehabilitation cycle is being studied in relation to life-cycle costing based on the realization that making rehabilitation cost-effective would require minimizing the necessary investment. However, the progress of an actual structure’s deterioration cannot be predicted precisely without a collection of inspection data, and therefore, at present the rehabilitation cycle is merely calculated on the idealized progressive deterioration hypothesis. In this study, the optimal life cycle of reinforced concrete deck slabs is derived from the residual life determined through a series of fatigue experiments on deck slabs cut out from existing bridges and rehabilitated afterwards. As a result, precise and cost-effective rehabilitation planning was made possible.


1984 ◽  
Vol 1 (1) ◽  
pp. 27-52
Author(s):  
Mahmud A. Faksh

I.Since the end of World War 11, approximately eighty new states havebeen established. Only two, Pakistan and Cyprus, have undergone theagony of dismemberment when Bangladesh broke off in 1973 and theTurkish Republic of Northern Cyprus was declared in 1983. The worldmay now be witnessing the possible breakup of yet a third state:Lebanon, whose disintegration has been accelerated since the June 1982Israeli invasion.Shortly after the invasion began, Henry Kissinger assessed itsconsequence for Lebanon’s future, concluding, “It is neither desirablenor possible to return to the status quo ante in Lebanon.” One possibleoutcome was that some Syrian and Israeli forces would remain in thenorthern and southern ends, respectively, and the central government’sauthority would ostensibly cover the rest of the country. Implicit in theKissinger diagnosis is the possibility of eventual partition.Though the gloomy assessment by the “wizard” of US. foreign policyshould by no means be construed as a portent of an official shift awayfrom the publicly stated US. support of “Lebanon’s sovereignty andterritorial integrity,” a shadow was cast on the country’s prospects.Subsequent developments have seemed to indicate that Lebanon’sdemise looms larger than at any time since the beginning of the civil warin 1975-76.For over a year and a half national fragmentation has proceededinexorably. What many people once could imagine only with difficulty,they now acknowledge: in reality, Lebanon is facing possible death. TheSouth (35 percent of the land area) is occupied by Israel; the North andthe Biqa’ (45 percent) are controlled by Syria; Kasrawan (15 percent) iscontrolled by the Christian Maronite forces (the Lebanese Front forces),which are not subject to the government’s authority. The rest of thecountry-beleaguered Beirut and environs-was until the February1984 breakdown under the government’s shaky control supported bysymbolic US., French, Italian, and British units. The Multi-NationalForce (MNF) was subject to increasing attacks by Muslim leftist factions,as witnessed in the October 23 bombing of the quarters of U.S.Marines and French troops. Thus, instead of keeping peace, the MNFbecame ,a partisan force trying to protect itself. The US. and Frenchforces in particular seemed to have outlived their usefulness as“peacekeepers.” Recurrent fighting in southern Beirut and in theadjacent Chouf mountains, that pitted Christian Maronites and armyunits against Shi‘ite and Druse Muslims constantly threatened theexistence of President Amin Gemayel’s government and consequently arenewal of the civil war. This situation culminated in February 1984 inthe resignation of the Shafiq al-Wazzan’s cabinet, the loss ofgovernment’s control of West Beirut to Muslim-leftist militias, and theimminent collapse of Amin Gemayel’s presidency ...


Author(s):  
Vyacheslav Falikman ◽  
◽  
Valentina Stepanova ◽  

В статье систематизированы основные критерии, необходимые для определения нормативных сроков эксплуатации бетонных и железобетонных конструкций, проведен анализ состояния отечественной и зарубежной нормативной базы в отношении требований к срокам службы железобетонных конструкций, рассмотрены основные нормативно-технические документы в области проектирования железобетонных конструкций зданий и сооружений по их жизнен-ному циклу. Описаны виды коррозионных повреждений железобетонных конструкций и определяющие их факторы, приведены согласованные на международном уровне модели долговечности для некоторых деградационных процессов. На основе проведенных работ подготовлены предложения по оценке коррозионного состояния эксплуатировавшихся железобетонных конструкций, их остаточной несущей способности, эксплуатационной пригодности, ожидаемого срока службы в заданных агрессивных условиях и методов определения нормативных сроков службы железобетонных конструкций. Даны предложения по разработке и актуализации ряда релевантных нормативных, технических и организационно-методических документов.


Author(s):  
Rosamond C. Rodman

Expanding beyond the text of the Bible, this chapter explores instead a piece of political scripture, namely the Second Amendment of the US Constitution. Over the last half-decade, the Second Amendment has come to enjoy the status of a kind of scripture-within-scripture. Vaulted to a much more prominent status than it had held in the first 150 years or so of its existence, and having undergone a remarkable shift in what most Americans think it means, the Second Amendment provides an opportunity to examine the linguistic, racial, and gendered modes by which these changes were effected, paying particular attention to the ways in which white children and white women were conscripted into the role of the masculine, frontier-defending US citizen.


Author(s):  
Patrick Sze-lok Leung ◽  
Anthony Carty

Okinawa is now considered as Japanese territory, without challenge from most world powers. However, this is debatable from a historical viewpoint. The Ryukyu Kingdom which dominated the islands was integrated into Japan in 1879. The transformation is seen by Wang Hui as a process of modernization. This chapter argues the issue from an international law perspective. It shows that Ryukyu was an independent State as demonstrated by the 1854 Ryukyu–US Treaty, although it sent regular tributes to China. The Japanese integration by coercion is not justifiable. The people of Ryukyu were willing to continue being a tributary State rather than part of Japan. Britain, as the greatest colonial power, did not object. China and the US attempted to intervene in this affair, but no treaty has so far been concluded. Therefore, the status of Ryukyu/Okinawa remains unresolved and may need to be revisited, while putting the history context into consideration.


Pathogens ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1073
Author(s):  
Juan-Carlos Saiz

West Nile virus (WNV) is a widely distributed enveloped flavivirus transmitted by mosquitoes, which main hosts are birds. The virus sporadically infects equids and humans with serious economic and health consequences, as infected individuals can develop a severe neuroinvasive disease that can even lead to death. Nowadays, no WNV-specific therapy is available and vaccines are only licensed for use in horses but not for humans. While several methodologies for WNV vaccine development have been successfully applied and have contributed to significantly reducing its incidence in horses in the US, none have progressed to phase III clinical trials in humans. This review addresses the status of WNV vaccines for horses, birds, and humans, summarizing and discussing the challenges they face for their clinical advance and their introduction to the market.


Author(s):  
Steven Nolan ◽  
Marco Rossini ◽  
Chase Knight ◽  
Antonio Nanni

AbstractWithin the last century, coastal structures for infrastructure applications have traditionally been constructed with timber, structural steel, and/or steel-reinforced/prestressed concrete. Given asset owners’ desires for increased service-life; reduced maintenance, repair and rehabilitation; liability; resilience; and sustainability, it has become clear that traditional construction materials cannot reliably meet these challenges without periodic and costly intervention. Fiber-Reinforced Polymer (FRP) composites have been successfully utilized for durable bridge applications for several decades, demonstrating their ability to provide reduced maintenance costs, extend service life, and significantly increase design durability. This paper explores a representative sample of these applications, related specifically to internal reinforcement for concrete structures in both passive (RC) and pre-tensioned (PC) applications, and contrasts them with the time-dependent effect and cost of corrosion in transportation infrastructure. Recent development of authoritative design guidelines within the US and international engineering communities is summarized and a examples of RC/PC verses FRP-RC/PC presented to show the sustainable (economic and environmental) advantage of composite structures in the coastal environment.


Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 565
Author(s):  
Changbo Liu ◽  
Zhendong Qian ◽  
Yang Liao ◽  
Haisheng Ren

This study aims to evaluate the economy of a steel bridge deck pavement scheme (SBDPS) using a comprehensive life-cycle cost (LCC) analysis approach. The SBDPS are divided into the “epoxy asphalt concrete system”(EA system) and“ Gussasphalt concrete system”(GA system) according to the difference in the material in the lower layer of the SBDPS. A targeted LCC checklist, including manager cost and user cost was proposed, and a Markov-based approach was applied to establish a life-cycle performance model with clear probability characteristics for SBDPS. Representative traffic conditions were designed using a uniform design method, and the LCC of SBDPS under representative traffic conditions and different credibility (construction quality as a random factor) was compared. The reliability of the LCC analysis approach was verified based on the uncertainty analysis method. Based on an expert-scoring approach, a user cost weight was obtained to ensure it is considered reasonably in the LCC analysis. Compared with the cumulative traffic volume, the cumulative equivalent single axle loads (CESAL) have a closer relationship with the LCC. The GA system has better LCC when the CESAL is less, while the EA system is just the opposite. The breaking point of CESAL for the LCC of the EA system and the GA system is 15 million times. The LCC analysis of SBDPS should consider the influence of random factors such as construction quality. The comprehensive LCC analysis approach in this paper can provide suggestions for bridge-management departments to make a reasonable selection on SBDPS.


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