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| Portfolio > Dam Engineering > Dam Engineering Project Detail
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Hickory Log Creek Dam
Location
Canton, Georgia
Client
City of Canton, Georgia (25%)
Cobb County-Marietta Water Authority (75%)
Services Provided
Alternatives Analysis
Geologic and Geotechnical Site Investigation
Geophysical Surveys
Hydrologic Analysis
RCC Gravity Dam Design
RCC Mix Laboratory Program
Project Overview
The Hickory Log Dam is a new 170-foot high dam approximately 1,000 feet long. The roller compacted concrete (RCC) dam will be the largest non-federal dam in Georgia. Schnabel’s site investigation included borings and geophysical surveys to verify subsurface conditions between boreholes. The design for the selected RCC gravity dam required consideration of the deeply weathered rock on both abutments, variable rock depths, unique valley topography with extensive rock outcroppings on one abutment, foundation seepage concerns due to weathered rock and a narrow ridge line on one abutment, water supply and quality issues, RCC facing systems, and design of a spillway with converging training walls.
In-situ field investigation included pressure meter testing of weathered rock and water pressure testing of the foundation rock. Laboratory testing included direct shear tests of the rock and rock/concrete interface to obtain the strength parameters for the stability analysis. Schnabel performed both a static and dynamic finite element analysis to evaluate the stability of the dam with different sections and at various loading conditions. Schnabel designed a two-line grout curtain and seepage control cutoffs and collection components based on data from the field program.
Schnabel completed a hydrologic analysis of the watershed for storms events ranging from the 2-year through the Probable Maximum Precipitation (PMP). Based on this analysis, the RCC dam design included a 250-foot long spillway consisting of a 110-foot section with 6-foot high crest gates, designed to pass the full Probable Maximum Flood (PMF) of 42,000 cfs. Due to topographic constraints, the spillway over the dam has to converge from 250 feet to 140 feet at the stilling basin. Schnabel, in conjunction with Utah State University, completed a 1:25 scaled model of the spillway and stilling basin to develop the appropriate rating curve and for optimizing sizing of the stilling basin.
An extensive RCC mix laboratory program was performed to optimize the cementitious materials and the aggregate gradation. Accelerated curing of RCC cylinders was utilized to estimate 360-day strengths.
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