Composite reliability model for local scour around cylindrical bridge piers

Bridge scour is an extremely complex phenomenon because of the random characteristics of sediment laden flow in close proximity to piers and abutments. This occurrence leads to high uncertainties and unavoidable risk in bridge pier and abutment design. In this study, a composite reliability model is developed for the reliability assessment of bridge pier scour using static resistance - loading interference. Based on the physical interpretation of the phenomenon and a statistical analysis of the available information, the relative maximum scour depth (corresponding to the minimum required relative pier footing elevation) and the linear combination of the relative approach flow depth and flow Froude number are defined as the system resistance and external loading, respectively. By examining a set of laboratory and field data, a two-parameter bivariate lognormal distribution is found to represent the joint probability density function of resistance and loading. Reliability expressions are developed in terms of resistance. Use of the model is illustrated in a practical application in which a relationship is obtained between the reliability and safety factors under various return periods. This information is of importance in decision making.


Generalized reliability model for local scour around bridge piers of various shapes
Yanmaz, Ali Melih (2001-10-01)
Excessive local scour around piers and abutments is known as a major cause of bridge failure induced by hydraulic deficiencies. Complexity of the scouring phenomenon and high degrees of uncertainties in governing parameters lead to an unavoidable risk in bridge pier design. In this paper, a generalized reliability model based on static resistance-loading interference is developed for the assessment of reliability of bridge scour for various pier shapes. In the model, the relative maximum scour depth and the...
Dynamic Reliability in Bridge Pier Scouring
Yanmaz, Ali Melih (2002-09-01)
Many bridges crossing wide rivers fail due to excessive local scour around piers and abutments during heavy floods. Because of the random nature and complexity of the overall scouring phenomenon through the bridge opening, there exist uncertainties leading to an unavoidable risk in bridge foundation design. A reliability-based assessment of bridge pier scour is required to examine the relationship between safety factors and reliability, which are key parameters for decision making in design. Herein, a dynam...
Evaluation of Scour Risk at Foundations of River Bridges
Yanmaz, Ali Melih; Çalamak, Melih (2016-07-01)
River bridges are exposed to more inconvenient conditions due to the structure-flow interaction compared to bridges having no contact with flow. Therefore, one of the most important components of the bridge failure risk is the risk induced by soil-flow interaction. In this study, the uncertainties of the hydrological and hydraulic parameters affecting the scouring around bridge piers are examined using appropriate probability density functions. In the analyses, the uncertainties involved in the temporal var...
Numerical investigation of coherent structures forming around bridge piers sitting on an inclined surface
Hesap, Emre; Köken, Mete; Department of Civil Engineering (2021-11)
Coherent structures forming around the piers play an important role in the formation of scour hole. Detached Eddy Simulation is used in this study to investigate the three-dimensional coherent structures forming around bridge piers which sit on an inclined surface. Initiation of the scour process at flat bed conditions is investigated within the current study. Two cases are investigated one with the lower Reynolds number case which is typical for flume experiments whereas the larger Reynolds number case re...
Interaction between bridge abutment and piers concerning local scour
Akbulut, Ömer Faruk; Göğüş, Mustafa; Kökpınar, Mehmet Ali; Department of Civil Engineering (2020-8)
Flowing water usually causes transportation of loose non-cohesive materials, called sediment in literature, in natural open channels such as rivers and canals with a transportable material bed. This sediment transportation is observed in two different situations; deposition and erosion. Excessive erosion leads in scouring. Scouring can be classified in three groups; general, contraction and local scour. Scouring namely removal of bed material from bridge sites cau...
Citation Formats
A. M. Yanmaz, “Composite reliability model for local scour around cylindrical bridge piers,” CANADIAN JOURNAL OF CIVIL ENGINEERING, pp. 520–535, 2001, Accessed: 00, 2020. [Online]. Available: