• Proceedings of the Korean Geotechical Society Conference
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• 2002.11a
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• pp.168-187
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• 2002

Scour is the physical or chemical attack of flowing water which excavates and carries away material from stream beds and banks. Especially, hydraulic structures such as bridge piers and abutments placed in the channel causes the changes of the flow pattern like acceleration, the formation of vortices, and scour around the structures. Channel scour, especially bridge pier scour is the leading cause of bridge failures. It is very important to apply appropriate methods for both of scour analysis and protection. In this paper, several methods world-widely used for bridge scour analysis and protection are introduced and compared.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.337-340
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• 2011

In this study, qualitative and quantitative evaluations are performed using the hydraulic analysis of fiber stone for bridge pier scour protection. We can consider that the effective scour protection should be suggested from the side of hydraulic stability, structure stability, and permissible tractive force. The perfect verification, however, on the fiber stone for bridge pier scour protection is not sufficient because of short literatures and experiments on the field study. The continuous research, therefore, will be needed to establish reliable verification using literatures investigation and the various experiments on the fiber stone for bridge pier scour protection.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.598-602
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• 2006

Local scour is associate with particular local types of vortex around bridge piers. This paper is method of protection local scour for the existing Busan City subway 3 Line bridge piers and Gupo large bridge piers. In order to take design of protection of local scour this bridge piers, We calculate the local scour hole of depth , scour width, riprap construction , filter construction by formulas. We had experimental hydraulic model test for this bridge piers in order to take proof for the calculation of local scour. We knew that the vortex intensifies the local flow velocities and acts to erode sediment from the scour hole and transport it downstream. As the result of hydraulic model test, we could suggest three types method of protection local scour this bridges. We knew that FHWA HEC-18(Richardson et al. 2001: Modified CSU) Formula is useful to checking calculation as application of field. One is pier protection using the sheet piles and riprap, the others are pier protection using the riprap with filter and to make renew Wall-caisson. The best method of protection for the existing Busan City subway 3 Line bridge piers and Gupo large bridge piers is pier protection using the sheet piles and riprap.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.2
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• pp.203-211
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• 2008

More recently, the massive marine bridges in a ship passage have been constructed on the sea. Therefore, the ship impact protection for the bridge-piers are installed to consider the possibility of vessel collision danger. Due to the ship impact protection, the pier-scour characteristics are changed in comparison with the condition without the ship impact protection (SIP). In this study, the physical modeling for the Incheon Sea-Crossing Bridge was performed to analyze the pier-scour characteristics with respect to the vessel collision protection. The rigid and movable bed tests were conducted to evaluate the flow pattern, scour depth, and scourhole with and without the ship impact protection. The experimental results for the maximum scour depth is increased 0.24 m in W1 pier at the same location and 2.4 m in W2+3+4 piers due to the SIP installation. Especially, the maximum scour depth in W2+3+4 piers was occurred around the SIP.

• Journal of the Korean Society of Safety
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• v.15 no.1
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• pp.126-131
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• 2000

This study based on the laboratory works, analyzes factors affecting local scour in order to understand various characteristics of the local scour surrounding bridge piers. Attached with scour protection device as a method for decreasing local scour, it carries out the laboratory experiments and calculates the scour depth. From the experiments attached with the scour protection devices, it seems possible to reduce the scour depth as the protecting plate, column and sacrificial piles are built in the same height with flume bed at pier or footing upstream interrupted falling-flow. And then it could reduce scour depth. The paper presents the following research results: First, the decreasing degree of scour depth is in order of protecting column, protecting plate, sacrificial piles and non-protecting facilities. However, it shows no meaningful difference between protecting column and protecting plate. Second, when $L_p/b$=0.5~1, the decreasing effect of scour depth reached the maximum of 40 percents.

• Journal of Korea Water Resources Association
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• v.31 no.3
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• pp.269-277
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• 1998

Laboratory flume experiments to investigate the characteristics of the flows and local scour around circular bridge pier in a curved channel are performed. In this study, the effect of a circular collar device for controlling the depth of scour is examined. The scour depth with a collar is about 40% of the scour depth without collar in the straight course of the flume while it is about 44% of the scour depth without collar at the location of 150' in the curved channel. As the results of experiments using the collar of which diameter is twice of pier, the reduction of scour depth is the most effective in a straight channel when the location of collar is 0.2h( h:depth) below the channel bottom. And, the reduction of scour depth is the most effective in a curved channel when the location of collar is 0.1h below the channel bottom.

• Journal of Korea Water Resources Association
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• v.41 no.8
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• pp.845-854
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• 2008

The old bridge of Woljeong-gyo, which has the fluvial history and culture, represents the ancient construction and civil engineering techniques. It is the oldest stone bridge in Korea and currently restored with its vicinities. In this study, the experimental model was used to analyze the hydraulic characteristics, the local pier-scour depth without scour protection, and the stability of riprap protection using the old grid type panels and stones for Woljeong-gyo of the study area. The water levels were increased around 30cm due to the restored bridge piers and foundations and the effects went up to 200m upstream. The maximum scour depth of 5.4m was measured and the scour protection tests were performed with the riprap size calculated using empirical equations and the existing scour protection range. The riprap of the existing scour protection in the upstream side was broken away, while the riprap of extended scour protection was very stable for the design flood condition of Woljeong-gyo area.

• Journal of Korean Society of Disaster and Security
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• v.11 no.2
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• pp.61-67
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• 2018

Scour protection methods can be categorized as two types: The first is to reduce the horseshoe and wake vortices which are the main reasons for local scour. Either small cylindrical structures or separated vertical deflectors can be placed in front of the pier or the horizontal deflector (or collar) can be attached to the pier like the spoiler to reduce the dynamics of vortical structures. The second is to employ the protection layer to keep the bed material in place, which is a common method with a merit of immediate effect by using block mat or tetrapod. This study examined the effect of scour reduction using the former method. The relationship between the reflector interval and reduction of scour was not clear. It is assumed that the width of the reflector is somewhat correlated with the reduction of the scour. As the KC numbers increases, the Effect of Scour reduction rate is shown to decrease. Also, Scour reduction rate showed a rapid change at $U_R=25$ or KC = 8.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09a
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• pp.4-5
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• 2005

• Journal of Korea Water Resources Association
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• v.33 no.6
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• pp.725-731
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• 2000

Experimental studies were conducted in a clear water condition to investigate the functioning of a sack gabion as a scour countermeasure at bridge piers. For different sizes of fill materials of sack gabions no difference was observed in the initial movement of sack gabions. Significant factors on the dislodging of sack gabions are approaching flow depth and velocity, pier width, and thickness and length of sack gabions. It was observed that the stability of the sack gabions is increased in a collective body of riprap stones than the placement of individual riprap stone. The length of a sack gabion has significant effect on its initial movement and the stability of a sack gabion was found to be increased by lengthening the length of gabions. The experimental results were used to derive formulas sizing gabions for scour protection at bridge piers. piers.