Current Issue : January - March Volume : 2017 Issue Number : 1 Articles : 5 Articles
Real bridge structures are affected by environmental conditions.The environmental loads in time cause the degradation of concrete and reinforcement. The diagnostics of real state of existing bridges are very important due to actual degradation and corrosion. In the frame of research activities of Department of Structures and Bridges, Civil Engineering Faculty, University of Ã?â?¡Zilina, the real bridge structure was observed for a few years. It is girder reinforced concrete bridge near town of Ã?â?¡Zilina in Slovakia. The results of diagnostics which focused on reinforcement corrosion are presented. The paper deals with reinforcement corrosion and its influence on the moment resistance of the existing concrete structures....
Design of ACM life cycle is defined with respect to traffic load acting on the pavement and road class for a period of about 20\nyears. In practice, reconstruction is usually pending until the end of the life cycle after which the reconstruction takes place and the\noriginal materials are replaced by new materials. Life cycle of the pavement construction in road structure is significantly longer\nthan that of the ACM; it is therefore necessary to consider ACMfroma long termviewpoint, that is, exceeding their life expectancy.\nThis paper describes a methodology which consists of analytical calculations, experimentalmeasurements, and optimization of the\nACMlife cycle with the use of a rehabilitation action to provide new physical properties of pavement surfacing in different periods\nof the original life cycle. The aim is to attain maximal economic effectiveness, by minimizing financial costs for rehabilitation\nand maintenance and economic costs of road user. Presented method allows deriving optimal life cycle from various rehabilitation\nalternatives for particularACMwith the fact that all the necessary parameters are derived fromspecific experimentalmeasurements\nand calculations. The method is applicable to all types of ACM materials; however, for each material, it is necessary to carry out\nthe necessary measurements and tests. The article describes the methodology and case study results for a particular type of ACM\nmaterial....
The effects of crack width on chloride ingress and mechanical behavior of reinforced concrete (RC) specimens were experimentally\nstudied after exposure to 300 cycles of freeze-thaw and seawater immersion (75 times). Cracks were induced prior to exposure by an\neccentric compression load which was sustained until the end of the exposure period. The maximum cracks widths induced in the\nfour column specimens were 0, 0.06, 0.11, and 0.15 mm, respectively. Results show that when the crack width was less than 0.06 mm,\nthe effect of cracks on chloride ingress could be neglected. However, when the crack width was more than 0.11 mm, chloride ingress\nwas accelerated. Results of static loading tests show that both yield load and ultimate load of RC columns decreased as crack width\nincreased.When the crack width was 0.15 mm, yield load and ultimate load of RC column specimen decreased by 17.0% and 18.9%,\nrespectively, compared to a specimen without cracks. It was concluded that crack width significantly promoted local chloride ingress\nand mechanical performance degradation of RC structures in cold coastal regions or exposed to deicing salts....
Recent developments in earthquake engineering indicate that probabilistic seismic\nrisk analysis (PSRA) is becoming increasingly useful for the evaluation of structural\nperformance in accordance with building codes. In recent years, the field of seismic\nresistance design has been undergoing a critical shift in focus from strength to performance.\nHowever, current earthquake resistant design procedures do not relate\nbuilding performance to probability. A lack of sufficient empirical data has highlighted\ngaps in this research. This study integrated results from the analysis of\nstructural fragility and seismic hazard in Taiwan to perform PSRA to examine the\neffectiveness of building code in mitigating the risks associated with earthquakes.\nFactors taken into account included the effect of construction materials, building\nheight, and building age. The results of this study show that the probability of exceeding\ndamage associated with the CP level in buildings of light steel, pre-cast concrete,\nand masonry, exceeds 2%. These buildings fail to meet the performance objectives\noutlined in FEMA-273....
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