A Comparative Study on the Efficiency of Reliability Methods for the Probabilistic Analysis of Local Scour at a Bridge Pier in Clay-Sand-Mixed Sediments

In this work, the performance of reliability methods for the probabilistic analysis of local scour at a bridge pier is investigated. The reliability of bridge pier scour is one of the important issues for the risk assessment and safety evaluation of bridges. Typically, the depth prediction of bridge pier scour is estimated using deterministic equations, which do not consider the uncertainties related to scour parameters. To consider these uncertainties, a reliability analysis of bridge pier scour is required. In the recent years, a number of efficient reliability methods have been proposed for the reliability-based assessment of engineering problems based on simulation, such as Monte Carlo simulation (MCS), subset simulation (SS), importance sampling (IS), directional simulation (DS), and line sampling (LS). However, no general guideline recommending the most appropriate reliability method for the safety assessment of bridge pier scour has yet been proposed. For this purpose, we carried out a comparative study of the five efficient reliability methods so as to originate general guidelines for the probabilistic assessment of bridge pier scour. In addition, a sensitivity analysis was also carried out to find the effect of individual random variables on the reliability of bridge pier scour.

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A comparative study of solo and hybrid data driven models for predicting bridge pier scour depth

Marine Georesources and Geotechnology ◽

10.1080/1064119x.2020.1735589 ◽

2020 ◽

pp. 1-11

Author(s):

Kourosh Qaderi ◽

Fahime Javadi ◽

Mohamad Reza Madadi ◽

Mohammad Mehdi Ahmadi

Keyword(s):

Comparative Study ◽

Bridge Pier ◽

Data Driven ◽

Scour Depth ◽

Pier Scour ◽

Hybrid Data ◽

Bridge Pier Scour

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Gene-expression programming to predict pier scour depth using laboratory data

Journal of Hydroinformatics ◽

10.2166/hydro.2011.008 ◽

2011 ◽

Vol 14 (3) ◽

pp. 628-645 ◽

Cited By ~ 25

Author(s):

Mujahid Khan ◽

H. Md. Azamathulla ◽

M. Tufail

Keyword(s):

Gene Expression ◽

Gene Expression Programming ◽

Laboratory Data ◽

Bridge Pier ◽

Scour Depth ◽

Bridge Scour ◽

Regression Equations ◽

Pier Scour ◽

Depth Prediction ◽

Bridge Pier Scour

Prediction of bridge pier scour depth is essential for safe and economical bridge design. Keeping in mind the complex nature of bridge scour phenomenon, there is a need to properly address the methods and techniques used to predict bridge pier scour. Up to the present, extensive research has been carried out for pier scour depth prediction. Different modeling techniques have been applied to achieve better prediction. This paper presents a new soft computing technique called gene-expression programming (GEP) for pier scour depth prediction using laboratory data. A functional relationship has been established using GEP and its performance is compared with other artificial intelligence (AI)-based techniques such as artificial neural networks (ANNs) and conventional regression-based techniques. Laboratory data containing 529 datasets was divided into calibration and validation sets. The performance of GEP was found to be highly satisfactory and encouraging when compared to regression equations but was slightly inferior to ANN. This slightly inferior performance of GEP compared to ANN is offset by its capability to provide compact and explicit mathematical expression for bridge scour. This advantage of GEP over ANN is the main motivation for this work. The resulting GEP models will add to the existing literature of AI-based inductive models for bridge scour modeling.

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Mathematical Modeling of Local Scour at Slender and Wide Bridge Piers

Journal of Fluids ◽

10.1155/2016/4835253 ◽

2016 ◽

Vol 2016 ◽

pp. 1-19 ◽

Cited By ~ 7

Author(s):

Youssef I. Hafez

Keyword(s):

Local Scour ◽

Bridge Pier ◽

Angle Of Repose ◽

Bridge Piers ◽

Bridge Scour ◽

Pier Scour ◽

Bed Scour ◽

Bed Material ◽

Bridge Pier Scour ◽

Mitigation Methods

Most existing equations for predicting local scour at bridge piers suffer from overprediction of the scour depths which results in higher foundation costs. To tackle this problem, a mathematical model for predicting bridge pier scour is developed herein based on an energy balance theory. The present study equation was compared to commonly used bridge scour equations using scour field data in USA. The developed equation has several advantages among which we have the following: it adds to the understanding of the physics of bridge pier scour, is valid for slender and wide piers, does not suffer from overprediction of scour depths, addresses clear water and live bed scour, and includes the effects of various characteristics of the bed material such as specific gravity (or density), porosity, size, and angle of repose. In addition, the developed equation accounts for the debris effect and aids in the design of scour mitigation methods such as collars, side bars, slots, and pier protective piles.

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