Concrete structures are exposed to aggressive environmental conditions that lead to corrosion of the embedded reinforcement and pre-stressing steel. Consequently, the safety of concrete structures may be compromised, and this requires a significant budgets to repair and maintain critical infrastructure. Prediction of structural safety can lead to significant reductions in maintenance costs by maximizing the impact of investments. The aim of this paper is to establish a framework to assess the reliability of existing post-tensioned concrete bridges. A time-dependent reliability analysis of an existing post-tensioned involving the assessment of Ynys-y-Gwas bridge has been presented in this study. The main cause of failure of this bridge was corrosion of tendons, making it a relevant case study to evaluate the effect of corrosion on bridge safety. Uncertainties associated with material properties, geometry, loads and corrosion parameters are taken into account. The probabilistic models of the uncertainties are combined with a non-linear finite element analysis to study the effect of tendons pitting corrosion on the post-tensioned concrete bridge. The limit state function considered is flexural strength. The Monte-Carlo simulation (MCS) method is used to compute the statistical parameters of the resisting bending moment through a MATLAB code running ABAQUS. It was found that the reliability index for the first year of bridge service life is below the minimum value acceptable for structures. The study confirmed that this bridge was a high risk structure due to its design and location. The proposed framework can be used by engineers and researchers as a tool to support decision for segmental post-tensioned (PT) bridges maintenance since they need for a regular inspection due to their risk to corrosion.
This study attempts to provide an approach analysis for the news, depending on the bases and principles which conceptuality semiotic researchers of this field first of them «A. J. Gremas» for the theory of «narrative discourse analysis», to more clarify we tried to apply it on a published press- news, to concludes the most important steps and methods that are necessary to follows gain more understanding of the press- news.
The study focused on the identification of the natural relation between the organizational components, and the most important is the organizational structure, which not hid its effect on each function and operation of the organizational structure through commanding the individual craters and its forms according to the requirement of these function, also it has relation with an organic synthesis that between the dimensions of the organic synthesis and the practice side in the commission of Integrity.
The problem of the research pensioned in some questions about hypothesis and theoretical parts, in which they go a mention about the hypothesis questions is to use all the knowledge's in this atmosphere and th
... Show MoreThis study was conducted on a sample of commercial banks in Iraq, chosen according number of considerations for twenty banks, contained two public banks and eighteen private banks. &
... Show MoreThis study was conducted to study the cytogenetic effect of both alcoholic and water extracts of propolis on mice. Three different samples of propolis were collected from three different regions of Iraq (Najaf, Arbil and Baghdad) to be used in this study. The cytotoxic effect of two different doses of each extracted sample was measured by employing cytogenetic analysis which included (mitotic index (MI), chromosomal aberrations (CAs), micronucleus index (MN) and sperm abnormalities). Results showed that significant increase in MI and significant reduction in MN, CAs and sperm abnormalities percentage were seen after treatment with both alcoholic and water extract of the three samples when compared with negative control, and alcoholic extrac
... Show MoreThis research dealt with study of cladistics taxonomy of five species related to the genus Rumex L. and Polygonum L. from family polygonaceae in Iraq by using Mesquite software V.2.75. This research support strongly delimiting the species P. aviculare L. and P. lapathifolia L.as suggested in floras publication while R. dentatus L. is setted in single group whereas R. vesicarius L. and R. conglomeratus Murray were included in the same group. Also, this study involved characteristics of shape, dimensions, color, and ornamentation of seeds and fruits as the seed forms were ranging from lenticular to trigonous. In terms of size calculations, the seeds of R. vesicarius was recorded the higher range (4.0- 4.5) mm in length w
... Show MoreThe study of services in villages is one of the imperative matters that must be focused on, because it leads to increased attention, which reduces the differences between the countryside and the urban. The extent of its.
It is well known that community services need to be reached by a person, unlike the anchor services that reach people, here the population distribution plays an important and prominent role in signing these services, so the dispersed distribution pattern and the gathering pattern appeared in the distribution, thus an effect on the time and distance that the person walked to obtain The services are community-based. Therefore
... Show MoreThe main objectives of this study are to study the enhancement of the load-carrying capacity of Asymmetrical castellated beams with encasement the beams by Reactive Powder Concrete (RPC) and lacing reinforcement, the effect of the gap between top and bottom parts of Asymmetrical castellated steel beam at web post, and serviceability of the confined Asymmetrical castellated steel. This study presents two concentrated loads test results for four specimens Asymmetrical castellated beams section encasement by Reactive powder concrete (RPC) with laced reinforcement. The encasement of the Asymmetrical castellated steel beam consists of, flanges unstiffened element height was filled with RPC for each side and laced reinforced which are use
... Show MoreThere are many events which causes nonproductive time (NPT) in the drilling industry. The mostly effective in this NPT is pipe sticking event. A considerable amount of time and resources can be spent in efforts to free a stuck pipe. In addition, Unsuccessful fishing operations results in costly alternatives including side-tracking. The drilling in Khabaz oil field poses many operational challenges among of them stuck pipe , lost circulation, flow of salt water during drilling, and hole caving. Stuck pipe can be considered the quite difficult problem in Khabaz oil field due to associated incidents which lead to NPT activities.
Well Khabaz -34 was selected to study the problem of stuck pipe in this field. An analysis of stuck pipe event