Publication: Peramalan kedalaman keruk di sekitar pier menggunakan kaedah regresi teguh
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Date
2005-04-01
Authors
Mohamed, Ahmad Hakimi
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Abstract
Over the decades, excessive local scour around bridge piers have been the major contribution factors for bridges deficiencies and failures. Technological breakthroughs in modern engineering have provided efficient tools for construction experts and engineers in making statistical analysis, to find the best method to deal with this phenomenon. The analysis is crucial since it would provide the quantitative evaluations to designers, which would help them to model a structure that combined safety, balances and economics. There are many reasons why scour became a major concern in designing bridges. Bridges that
become inundated during floods have slightly pressurized flow that impacts bridge piers and creates an aggravated scour condition. Bridge failure mode which induced by scour is relatively complex since it involved a combination of factors such as the combined ejects of three dimensional river bed degradation, localize scour due to channel constriction at the bridge opening, and the accelerated flow and generation of vortices at the bridge opening which caused local scour around bridge piers and abutments. Due to the seriousness of the scour problem, bridge design will take into consideration all factors available. Equations
were developed by subject matter experts, to make forecasting to eliminate or minimize its impact on the structure. Unfortunately, the ever changing environmental phenomena have made those equations not suitable to be applied to all conditions. Studies by Simon & Senturk (1992) and Kafi & Alam (1995) have proposed various scour equation which have been developed in the literature. It is found that the precision and accuracy of laboratory based equations can improved if the coefficient and exponent of these equations were derived using field data. Apart from that, the equations are dependent to several factors;
flow criteria such as flow depth, flow velocity and vortex velocity, shape of the pier and size of sediment. Based on the suggestion by Kafi & Alam (1995), Ab.Ghani & Nalluri (1996), new equations were developed to predict pier scour using the available field data. In this study, analysis has been made by using S-PLUS with 3 method of analysis.