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|Title:||Risk analysis of design-improvement alternatives to the Lindy Claiborne Boggs Lock and Dam|
|Authors:||BMA Engineering, Inc.|
United States. Army. Corps of Engineers. New England District.
Innovations for Navigation Projects Research Program (U.S.)
Ayyub, Bilal M.
Blair, Andrew Nyakaana.
Patev, Robert C.
Probabilistic risk assessment
Preliminary hazard analysis
Lindy C. Boggs Lock and Dam
|Publisher:||Information Technology Laboratory (U.S.)|
Engineer Research and Development Center (U.S.)
|Series/Report no.:||ERDC/ITL TR 02-1.|
Abstract: This report summarizes a review and assessment of the Preliminary Hazard Analysis (PHA) for lower lock approach sediment management improvements to the Lindy Claiborne Boggs Lock and Dam. The review assessed the probability of catastrophic failure during the construction and utilization phases of the lock-improvement alternatives. The Lindy C. Boggs Lock and Dam experiences large water-level fluctuations. To accommodate the large fluctuation of water levels, floating guide walls upstream and downstream of the lock were incorporated into the plans. To retain the riverside lock wall backfill, a concrete “T-wall” was constructed for a distance of 130 ft (40 m) perpendicular from the lock on the downstream end. Anticipating that sediment would deposit in the navigation channel underneath the downstream floating guide wall, provisions were included in the original plans in the form of an earthen dike and a composite “I-wall” (steel sheetpiling and concrete wall) on top of the dike. The I-wall was connected to the T-wall and continued 130 ft offset from and parallel to the floating guide wall for 1,100 ft (335 m). The purpose of the dike and I-wall was to divert the flow and sediment from the floating guide wall and the navigation channel, thus providing a slackwater lock approach channel. Nonetheless, an average of approximately 310,000 cu yd (237,000 cu m) of silt has been removed annually from the lower lock approach channel at Lindy C. Boggs Lock and Dam. Three alternative improvements are proposed to control this sedimentation: the provision of a new fixed guidewall with dike removal, the provision of a new fixed guidewall with retention of dike, and the barrier extension and use of concrete panels. The U.S. Army Engineer District, Vicksburg, has the requirement to determine the probability of catastrophic failure during the construction and utilization phases of the lock-improvement alternatives, including potential catastrophic damage occurring to the floating guidewall pontoons while they are being removed, transported to and from their temporary storage area, and reinstalled. Catastrophic damage is defined either as the sinking or destruction of any one or all of the pontoons or as sufficient damage occurring to any pontoon so as to require repair or replacement. The probability of this type damage occurring within the navigation channel or the lock chamber, thus shutting down the waterway to barge traffic until the sunken or destroyed pontoon can be removed from the navigation channel, is also required. The methodology used in this analysis covers key aspects of the PHA process. The proposed risk-based methodology begins with system definition and progresses to defining work tasks for the three alternatives. The tasks in every phase of each alternative are assessed for risk, examining associated initiating events, failure scenarios, consequences, and occurrence probability. Initiating events and failure scenarios are identified and enumerated. Information related to failure probability and consequences is not available from historical records, prediction methods, or literature review and is obtained by expert-opinion elicitation (see companion report entitled “Expert-Opinion Elicitation for the Risk Analysis of Design-Improvement Alternatives to the Lindy Claiborne Boggs Lock and Dam,” ERDC/ITL TR-02-2). The report findings are summarized using tables that include (for each location, system, or procedure) the hazard description, causal factors, hazard effect, initial risk, mitigating control, residual risk, and remarks. The results are provided in terms of initial risk ranking and hazard groups. The various risk-ranking categories are described and discussed.
|Rights:||Approved for public release; distribution is unlimited.|
|Appears in Collections:||Technical Report|